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Tropical and Temperate: Evolutionary History of Páramo Flora
Abstract
Biogeography of the tropical alpine flora of South and Central America, the páramo flora, has been studied by dividing genera
into tropical, temperate, and cosmopolitan chorological flora elements. Published molecular phylogenies of páramo genera are
reviewed to summarize knowledge about evolutionary history of the páramo flora and to assess congruence between chorological
and phylogenetic approaches. Molecular phylogenies suggest that both the tropical and temperate regions have been important
source areas for evolution of the páramo flora. Conclusions derived from chorological patterns regarding origin of genera
in páramo are mostly supported by phylogenetic data. Nevertheless, in Chuquiraga, Halenia, Huperzia, and Perezia the chorological scenario is rejected, and in Chusquea-Neurolepis, Elaphoglossum, Gunnera, Halenia, Jamesonia-Eriosorus, and Lasiocephalus independent colonization events from one or several source areas are suggested. Tropical and temperate genera contributed
equally to modern species richness of the páramo flora. Among temperate genera, the northern hemisphere genera gave rise to
more species in páramo than did genera from the southern hemisphere. So far, no unequivocal evidence has been provided for
migration of páramo genera to the temperate zones.
KeywordsAndes–Austral-Antarctic–Biogeography–Diversity–Holarctic–Plant migration–Tropical alpine
... The long Andean cordillera provided a pathway for ample latitudinal migrations of alpine species, especially during cold periods in the Pleistocene, when mountain forests retreated (Hooghiemstra et al. 2006;Sklenář et al. 2014;Nürk et al. 2020). Besides endemic taxa evolved in the cold tropics (e.g. the Espeletinae tribe), many other groups have migrated and colonized from the tropical lowlands and from temperate latitudes, including species/genera with holarctic, austral antarctic and wide temperate origins (Cleef 1979;Van der Hammen and Cleef 1986;Sklenář et al. 2011). ...
... Regarding biogeographic aspects, previous research has mainly focused on the historical and evolutionary phytogeography of the tropical Andean flora (Simpson andTodzia 1990, Young et al. 2002;Sklenář et al. 2011). Recently, Cuesta et al. (2020) evaluated the thermal niche traits of plant species and biogeographic groups in GLORIA summits of the tropical Andes. ...
... Thirteen growth forms were recorded: erect shrubs, prostrate shrubs, cushions, turf grasses, disperse grasses, tussock grasses, ferns, erect herbs, prostrate herbs, acaulescent rosettes, basal rosettes, caulescent rosettes and succulents (Appendix 2). We also assigned each recorded species to the biogeographical origin of its genus following Sklenář et al. (2011). Seven biogeographical origins were recorded: austral antarctic, cosmopolitan, holarctic, neotropical, páramo endemic, wide temperate and wide tropical (Appendix 2). ...
Tropical alpine ecosystems exhibit outstanding plant diversity and endemism while
being particularly sensitive to the impacts of climate change. Although understanding spatiotemporal changes in plant species composition, richness and community structure along tropical alpine altitudinal gradients is of primary importance, both the functional and historical/biogeographic dimensions of vegetation diversity remain largely unexplored. We used Generalized Linear Models and multivariate analyses to assess changes in species, growth forms, and biogeographic groups richness and abundance, in response to habitat variables along an elevation gradient in seven summits (3800 to 4600 m asl) in the Venezuelan Andes, studied using the standardized approach of the GLORIA-Andes monitoring network. The habitat variables assessed were soil temperature (-10 cm), soil organic matter, slope inclination, and substrate cover. We found 113 species, representing 72 genera, 32 families, 13 growth forms, and seven biogeographic origins, that included 25% of endemic elements. We observed richer vegetation, both in terms of species and growth forms, in summits with higher soil temperatures and higher SOM content, as well as higher biogeographic origin richness with increasing soil temperatures. The presence of holarctic elements increased toward higher elevations, while the occurrence of austral antarctic elements increased toward lower elevations. Our results indicate that biogeographic and functional approaches to vegetation diversity capture well the effect of abiotic filtering on community structuring in these tropical alpine environments. These findings constitute an important baseline for monitoring vegetation dynamics linked to climate change in the Venezuelan Andes by highlighting the functional and historical perspective on vegetation analyses, in contrast with more traditional approaches, based only on taxonomic species diversity.
... Another potential driver of primary succession specific to the páramos is their location at a biogeographic crossroad between temperate, tropical and endemic trends. Indeed, in this region, taxa may originate from temperate environments (Holarctic species from the North and Austral-Antarctic species from the South) or from tropical environments, including originating in the tropical páramo itself (Sklenář et al. 2011;Anthelme and Peyre 2020). The biogeographic origin of taxa has been observed to influence their elevational distribution in the páramo with, e.g., Holarctic genera becoming more abundant and páramo endemics becoming less abundant at higher elevations (Sklenář & Balslev 2007). ...
... The biogeographic origin of taxa has been observed to influence their elevational distribution in the páramo with, e.g., Holarctic genera becoming more abundant and páramo endemics becoming less abundant at higher elevations (Sklenář & Balslev 2007). Taxa of temperate origin may be preadapted to alpine environments, which would make them potentially more efficient for colonizing recently deglacierized terrains than their tropical counterparts, which first diversified in warm, moist environments (Sklenář et al. 2011;Gehrke 2018;Peyre et al. in press; but see Nürk et al. 2018). From this viewpoint, we might expect a deficit in species of tropical biogeographic origin during early primary succession. ...
... Species were grouped into CU as soon as they had a dense, hemispheric shape, providing a singular microenvironment. Species were also grouped into biogeographical origins -temperate, tropical and cosmopolite-following the classification of Sklenář et al. (2011) at the genus level, which means each species was grouped into the biogeographical origin of its genus. This was done to test to what extent the biogeographic origin of species conditions their establishment success during primary succession (Supplementary Material 4). ...
Early plant primary succession in recently deglacierized terrains is a good indicator of the species losses and gains that affect novel alpine plant communities migrating under the pressure of climate warming. In the tropical alpine -páramo- region of the northern Andes, home to the world's greatest alpine phyto-diversity, forced primary succession will condition the conservation of many species. Using a post-glacial chronosequence between the little ice age and present below the Conejeras glacier (Colombia) as a space-for-time substitution approach, we sought to determine how time since deglacierization affects the composition, the biogeographic origin and the growth form distribution of novel tropical alpine plant communities. Using an array of multivariate techniques and the Dirichlet model, we assessed relationships among plant communities and with environmental factors. Communities established in less than 169 years lacked a number of characteristic and endemic species usually found in the national park Los Nevados, such as Calamagrostis effusa, Senecio isabelis and Espeletia hartwegiana. Moreover, these communities have been colonized by non-native species, e.g., Rumex acetosella. Upright shrubs and large tussock grasses, characteristic of the alpine tropics, established slowly because they required highly organic, slow-developing soils. Taxa of tropical biogeographic origin were under-represented early after deglacierization in comparison with temperate taxa. These results suggest the existence of a strong climatic debt for some native species, tropical growth forms and taxa of tropical origin, which may translate into significant taxonomic and functional losses whereas the few observed gains concern the establishment of non-native species.
... Another potential driver of primary succession specific to the páramos is their location at a biogeographic crossroad between temperate, tropical and endemic trends. Indeed, in this region, taxa may originate from temperate environments (Holarctic species from the North and Austral-Antarctic species from the South) or from tropical environments, including originating in the tropical páramo itself (Sklenář et al. 2011;Anthelme and Peyre 2020). The biogeographic origin of taxa has been observed to influence their elevational distribution in the páramo with, e.g., Holarctic genera becoming more abundant and páramo endemics becoming less abundant at higher elevations (Sklenář & Balslev 2007). ...
... The biogeographic origin of taxa has been observed to influence their elevational distribution in the páramo with, e.g., Holarctic genera becoming more abundant and páramo endemics becoming less abundant at higher elevations (Sklenář & Balslev 2007). Taxa of temperate origin may be preadapted to alpine environments, which would make them potentially more efficient for colonizing recently deglacierized terrains than their tropical counterparts, which first diversified in warm, moist environments (Sklenář et al. 2011;Gehrke 2018;Peyre et al. in press; but see Nürk et al. 2018). From this viewpoint, we might expect a deficit in species of tropical biogeographic origin during early primary succession. ...
... Species were grouped into CU as soon as they had a dense, hemispheric shape, providing a singular microenvironment. Species were also grouped into biogeographical origins -temperate, tropical and cosmopolite-following the classification of Sklenář et al. (2011) at the genus level, which means each species was grouped into the biogeographical origin of its genus. This was done to test to what extent the biogeographic origin of species conditions their establishment success during primary succession (Supplementary Material 4). ...
Early plant primary succession in recently deglacierized terrains is a good indicator of the species losses and gains that affect novel alpine plant communities migrating under the pressure of climate warming. In the tropical alpine-páramo-region of the northern Andes, home to the world's greatest alpine phytodiversity, forced primary succession will condition the conservation of many species. Using post-glacial chronosequence between the little ice age and present below the Conejeras glacier (Colombia) as a space-for-time substitution approach, we sought to determine how time since deglacierization affects the composition, the biogeographic origin and the growth form distribution of novel tropical alpine plant communities. Using an array of multivariate techniques and the Dirichlet model, we assessed relationships among plant communities and with environmental factors. Communities established in less than 169 years lacked a number of characteristic and endemic species usually found in the national park Los Nevados, such as Calamagrostis effusa, Senecio isabelis and Espeletia hartwegiana. Moreover, these communities have been colonized by non-native species, e.g., Rumex acetosella. Upright shrubs and large tussock grasses, characteristic of the alpine tropics, established slowly because they required highly organic, slow-developing soils. Taxa of tropical biogeographic origin were under-represented early after deglacierization in comparison with temperate taxa. These results suggest the existence of a strong climatic debt for some native species, tropical growth forms and taxa of tropical origin, which may translate into significant taxonomic and functional losses whereas the few observed gains concern the establishment of non-native species.
... We used these pieces of information to select 11 species in Chamrousse ( Figure 9) and 12 species in Pico de Orizaba ( Figure 10). Below we describe each of the 23 species sampled (Figure 9 and 10), including taxonomic, morphological, ecological data (Straw 1962, Cházaro Basáñez 1992, Lauber, Wagner et al. 2018) and biogeographical data (Rzedowski 2001, Sklenář, Dušková et al. 2011 ...
... Another unique characteristic of the (sub)alpine tropics is that many locations contain species of Holarctic biogeographic origin in addition to species that originated in the tropics (Sklenář, Dušková et al. 2011). Therefore, despite belonging to the same growth form, two species of different biogeographic origins may display different adaptations to cold and drought (Sklenář, Kučerová et al. 2012). ...
... jorullense, D. jorullensis and S. roseus). See Figure 10 (material & methods) and Table S1 (Annexes) contains detailed description of each of the 11 sampled species, including taxonomic, morphological, ecological data (Straw 1962, Cházaro Basáñez 1992 and biogeographical data (Rzedowski 2001, Sklenář, Dušková et al. 2011. ...
Alpine regions are home to a high level of biodiversity that is particularly sensitive to global change because it is adapted to extreme environments. The future of alpine plant species in the face of the effects of global warming has been the subject of a growing body of work over the last two decades, allowing increasingly credible future distribution scenarios to be proposed. This is not the case in the tropical alpine regions, which are understudied. The objective of my thesis was to compare variations in functional traits and strategies of alpine species in a tropical site (Mexico, 11 species) and a temperate site (France, 12 species) and to estimate to what extent these variations are similar. I tested two hypotheses: (H1) that all species considered converge towards more resource conservation at higher elevations due to increasing constraints and (H2) that the climatic differences between the two sites generate different ecological niches between the two sites. My data collection was carried out along two 1000m-elevation gradients, each centred on the treeline. The traits measured were specific leaf area (SLA), leaf dry matter content (LDMC), leaf thickness, leaf area and individual height. I also used Grime's strategies as a synthetic indicator of strategy changes along the gradients. My results show that both groups of species converge towards more resource conservation at higher elevations (more conservative traits, more stress-tolerant species). A second striking result is that, on average, tropical species are less stressed (sensu Grime) and develop higher SLA in tropical sites than in temperate sites. These variations are correlated with a higher mean annual soil temperature in the tropical site than in the temperate site. There is thus a similarity in the responses of alpine plants along elevation gradients, whatever the latitude considered. In contrast, the fact that tropical species are on average more resource-acquisitive than temperate species indicates a wider ecological niche, which may be due to higher temperatures, a longer growing season and the absence of seasonal snow cover. These observations show that it is not sufficient to make scenarios for the future of alpine tropical biodiversity with data from temperate alpine regions only and that retrieving more data in the tropics is crucial.
... Studies of endemic floras of high altitudes of the Northern and Central Andes are of great importance to understand the evolution of one of the most diverse mountain ecosystems in the world in terms of species richness and endemism, the Páramo (Luteyn and Balslev 1992;Luteyn 1999;Sklenář et al. 2011Sklenář et al. , 2014Madriñán et al. 2013;Hughes and Atchison 2015). Páramo habitats, characterized by tussock grasses, large rosette plants, shrubs with evergreen, coriaceous and sclerophyllous leaves, and cushions are found in the tropical Andes from 3000 to 4500 m (Luteyn et al. 1999). ...
... They emerged by the end of the north-Andean orogeny ca. 3-5 Mya (van der Hammen and Cleef 1986;Graham 2009), and despite its recent age, the Páramo flora is especially rich in various groups, e.g., Asteraceae in general, Valeriana, Gentianella, Lupinus (von Hagen and Kadereit 2001;Briceño and Morillo 2002;Bell and Donoghue 2005;Hughes and Eastwood 2006;Sklenář et al. 2011). Many authors pointed out the important contribution of both temperate areas of the Americas as well as Neotropics as main sources in colonizing the Páramo (see Sklenář et al. 2011 for a summary). ...
... 3-5 Mya (van der Hammen and Cleef 1986;Graham 2009), and despite its recent age, the Páramo flora is especially rich in various groups, e.g., Asteraceae in general, Valeriana, Gentianella, Lupinus (von Hagen and Kadereit 2001;Briceño and Morillo 2002;Bell and Donoghue 2005;Hughes and Eastwood 2006;Sklenář et al. 2011). Many authors pointed out the important contribution of both temperate areas of the Americas as well as Neotropics as main sources in colonizing the Páramo (see Sklenář et al. 2011 for a summary). In recent years, many studies have focused on the evolution of plant groups from the Páramo, which have been very useful to understand the colonization of these environments (Bell and Donoghue 2005;Hughes and Eastwood 2006;Jabaily and Sytsma 2013). ...
Páramo, the most species-rich tropical mountain ecosystem, is relatively well-researched in terms of the diversity and evolutionary sources of its flora, yet we know very little about the diversification within this environment. This study aims to unravel the evolutionary history of Oritrophium, an endemic genus of alpine habitats in North and South America, with a disjunct and bi-modal distribution of its species diversity. We aim to disentangle the center of origin and radiation of the genus, and mechanisms structuring its genetic diversity at inter-and intra-specific level. We sampled 19 species (85% from the total) and extended the sampling at population level for the two widely distributed species, O. limnophilum and O. peruvianum, comprising 19 and 24 populations, respectively. Using nuclear ribosomal internal transcribed spacer (ITS) and trnL-trnF chloroplast DNA region, we reconstructed dated phylogenies to test the monophyly of the genus and unravel possible historical forces underlying its diversification. We also performed an ancestral area estimation to reconstruct the biogeographic history of the genus. At the population level, we constructed haplotype networks and run spatial analyses of molecular variance to explore possible mechanisms that operate on structuring the diversity at intraspecific level. Oritrophium resulted polyphyletic, with two species being closely related to Erigeron and three other species ambiguously related to Erigeron, Diplostephium, Linochilus, and/or Hinterhubera. The remaining 14 species formed a clade, Oritrophium s.s., that likely originated during the Early Pliocene in the Andes of northwestern Bolivia to southern Ecuador, the center of the genus' diversity. The group likely diversified with the emergence of the Páramo during the Late Pliocene and further dispersed mainly from South-to-North in the Pleistocene. This migration involved both, long-distance dispersal from the Central Andes to Mexico and gradual migration of the species along the Andes. Accordingly, Oritrophium s.s. appears as the first record of a long-distance dispersal from the Páramo of South America to North America. The dispersal pattern within South America was mirrored by the intraspecific population diversity and structure of the investigated species.
... Although the studied ecosystems are separated by only a short elevational range (500 m), this difference plays a determining role in species composition and diversity [16]. Several historical and ecological factors have likely acted synergistically to produce the observed differences in diversity [87][88][89][90][91]. Differences in plant species composition are likely related to biogeographical events, such as plant dispersal events that occurred during the late Pleistocene [91,92], the subsequent geographic isolation, and the prevalence of cold, seasonal climatic conditions in the Paramo, in contrast with the milder climate (i.e., warmer, misty, and less seasonal) prevailing in the Montane Forest [93]. ...
... Although the studied ecosystems are separated by only a short elevational range (500 m), this difference plays a determining role in species composition and diversity [16]. Several historical and ecological factors have likely acted synergistically to produce the observed differences in diversity [87][88][89][90][91]. Differences in plant species composition are likely related to biogeographical events, such as plant dispersal events that occurred during the late Pleistocene [91,92], the subsequent geographic isolation, and the prevalence of cold, seasonal climatic conditions in the Paramo, in contrast with the milder climate (i.e., warmer, misty, and less seasonal) prevailing in the Montane Forest [93]. This has resulted in a unique Paramo vegetation that differs notably from the adjacent Montane Forest [16]. ...
Many plant species in high montane ecosystems rely on animal pollination for sexual reproduction, however, our understanding of plant-pollinator interactions in tropical montane habitats is still limited. We compared species diversity and composition of blooming plants and floral visitors, and the structure of plant-floral visitor networks between the Montane Forest and Paramo ecosystems in Costa Rica. We also studied the influence of seasonality on species composition and interaction structure. Given the severe climatic conditions experienced by organisms in habitats above treeline, we expected lower plant and insect richness, as well as less specialized and smaller pollination networks in the Paramo than in Montane Forest where climatic conditions are milder and understory plants are better protected. Accordingly, we found that blooming plants and floral visitor species richness was higher in the Montane Forest than in the Paramo, and in both ecosystems species richness of blooming plants and floral visitors was higher in the rainy season than in the dry season. Interaction networks in the Paramo were smaller and more nested, with lower levels of specialization and modularity than those in the Montane Forest, but there were no seasonal differences within either ecosystem. Beta diversity analyses indicate that differences between ecosystems are likely explained by species turnover, whereas within the Montane Forest differences between seasons are more likely explained by the rewiring of interactions. Results indicate that the decrease in species diversity with elevation affects network structure, increasing nestedness and reducing specialization and modularity.
... Our results show differences in species composition and diversity of plants between two adjacent ecosystems at tropical high elevations. Local and regional environmental traits, and historical events likely act synergistically to produce the differences observed (Simpson, 1975;Hooghiemstra et al., 1992;Islebe, Hooghiemstra & Van der Borg, 1995;Islebe, Hooghiemstra & Van't Veer, 1996;Sklenář, Dušková & Balslev, 2011;Barrantes, 2009). In comparison to the adjacent Montane Forest, the Paramo has a lower richness of flowering species. ...
... Consequently, temporal turnover (beta diversity) of blooming plants also differed between ecosystems and such differences are likely related to the uniqueness of the Costa Rican Paramo vegetation (Cleef & Chaverri, 1992). The evolution of a unique vegetation in the Costa Rican Paramo, which differs notably from the adjacent Montane Forest, could be the result of several factors: (a) the plant dispersal events that occurred during the late Pleistocene (Simpson & Neff, 1992;Sklenář, Dušková & Balslev, 2011;Londoño, Cleef & Madriñán, 2014), (b) the geographic isolation when climate changed after the Pleistocene, and (c) the prevalence of cold climatic conditions at the summit of the Talamanca Mountain range. Vicariance driven by the climate shifts after the Pleistocene in conjunction with topographic isolation, has shaped the evolution of several plant clades within the Andean cordilleras (Simpson, 1975;Luebert & Weigend, 2014). ...
The Costa Rican Paramo is a unique ecosystem with high levels of endemism that is geographically isolated from the Andean Paramos. Paramo ecosystems occur above Montane Forests, below the permanent snow level, and their vegetation differs notably from that of adjacent Montane Forests. We compared the composition and beta diversity of blooming plant species using phenological data from functional plant groups ( i.e. , insect-visited, bird-visited and insect + bird-visited plants) between a Paramo and a Montane Forest site in Costa Rica and analyzed seasonal changes in blooming plant diversity between the rainy and dry seasons. Species richness was higher in the Montane Forest for all plant categories, except for insect-visited plants, which was higher in the Paramo. Beta diversity and blooming plant composition differed between both ecosystems and seasons. Differences in species richness and beta diversity between Paramo and the adjacent Montane Forest are likely the result of dispersal events that occurred during the last glacial period and subsequent isolation, as climate turned to tropical conditions after the Pleistocene, and to stressful abiotic conditions in the Paramo ecosystem that limit species establishment. Differences in blooming plant composition between both ecosystems and seasons are likely attributed to differential effects of climatic cues triggering the flowering events in each ecosystem, but phylogenetic conservatism cannot be discarded. Analyses of species composition and richness based on flowering phenology data are useful to evaluate potential floral resources for floral visitors (insects and birds) and how these resources change spatially and temporarily in endangered ecosystems such as the Paramo.
... Aragoa Kunth is the genus with approximately 19 species endemic to the alpine páramo biome in the northern Andes of Colombia and Venezuela. The species of Aragoa are shrubs and small trees up to 5-8 m tall, with needle-like or scale-bar leaves and reduced axillar racemose inflorescences bearing actinomophic flowers with four white petals [1][2][3][4][5]. Aragoa was been considered as a member of Scrophulariaceae until the polyphyly of this family was strongly confirmed by molecular phylogenetic data. ...
... As the rayless species of Plantaginaceae occur in very contrasting habitats ranging from springs, bogs, and tidal zones, to arid and alpine biomes, showing a variety of life forms from annual herbs to shrubs and small trees, the loss of rays is hard to explain in terms of their functional or adaptive value [42]. Although the position of rayless woody taxa (Aragoa, some Plantago and Veronica) on phylogenetic trees [6,43] strongly suggest their origin from herbaceous ancestors, the consideration of the raylessness as anatomical evidence for derived woodiness in these particular genera ( [5] following [44]) is highly questionable, at least for the Plantaginaceae. ...
Aragoa is a shrubby genus endemic to páramo in the northern Andes representing the sister group to Plantago and Limosella. Stem and leaf structure of Aragoa corrugatifolia were studied to clarify the evolutionary pathways and ecological significance of their anatomical traits. Aragoa and Plantago share a non-fascicular primary vascular system, rayless wood and secondary phloem, and anomocytic stomata. Aragoa is distinctive from most Plantaginaceae in the presence of cortical aerenchyma and of helical thickenings in vessels. Its procambium emerges in the primary meristem ring as a continuous cylinder. The view on the ring meristem and procambial strands as developmental stages in the formation of a primary vascular system is not relevant for Aragoa, and probably for other Plantaginaceae. The raylessness is synapomorphic for the crown clade of Plantaginaceae comprising Aragoa, Littorella, Plantago, Veronica, Picrorhiza, Wulfenia, and Veronicastrum. The loss of rays is thought to be predetermined by procambium rather than by the vascular cambium. The extremely narrow vessels with helical thickenings are presumably adaptive to hydric and thermic conditions of páramo. Cortical aerenchyma is thought to be a response to the local hypoxia caused by the water retained by ericoid leaves. Trichomes on juvenile leaves are expected to be the traits of considerable taxonomic importance.
... Another unique characteristic of the (sub)alpine tropics is that many locations contain species of Holarctic biogeographic origin in addition to species that originated in the tropics (Sklenář et al. 2011). Therefore, despite belonging to the same growth form, two species of different biogeographic origins may display different adaptations to cold and drought (Sklenář et al. 2012). ...
... jorullense, D. jorullensis and S. roseus). Supplementary Table S1 contains detailed description of each of the 11 sampled species, including taxonomic, morphological, ecological data (Cházaro Basáñez 1992;Straw 1962) and biogeographical data (Rzedowski 2001;Sklenář et al. 2011). ...
With the aim to explore how plants acclimate to elevation changes in the understudied (sub)alpine tropics we tested two hypotheses along a 1000-m elevation gradient in Mexico: (H1) due to a severe increase in abiotic constraints at higher elevations, the functional traits of the plant species will converge toward more resource conservation, and (H2) the specific growth forms and biogeographic origins present in the (sub)alpine tropics may influence the interspecific trait variation along the gradient. We measured five aboveground functional traits: specific leaf area (SLA), leaf dry-matter content (LDMC), leaf thickness, leaf area and plant height, of 11 species representing four growth forms: rosette, tussock grass, shrub and tree the soil microclimate. Microclimatic data revealed a steep decrease in soil water content at higher elevations. Across all species and all individuals, SLA, plant height and leaf area decreased with elevation, whereas LDMC and leaf thickness increased, all of which revealing adjustments towards resource conservation in line with H1. Consistently with H2, the functional traits of the growth forms that were characteristic of tropical alpine regions (tussock grasses and erect shrubs) were less sensitive to changes in elevation compared to more generalist growth forms such as forbs. In addition, within the growth form “rosette” the functional traits of species of tropical biogeographic origin changed with elevation, whereas those of Holarctic origin did not. Our data indicate a convergence of plant traits toward improved resource conservation at higher elevations, which may be influenced partially by the growth form and the biogeographical origin of plant species.
... Most of the biogeographic studies dealing with the Páramo province have been largely qualitative (e.g., Balslev & Luteyn, 1992;Cleef, 1978Cleef, , 1981Cuatrecasas, 1986;Hernández et al., 1992;Madriñán et al., 2013;Monasterio, 1986;Morales et al., 2007;Rangel, 2000;Sklenár et al., 2011;van der Hammen & Cleef, 1986;Vuilleumier & Monasterio, 1986). In the last years, some authors have analyzed quantitatively this province and produced biogeographic regionalizations (Díaz-Acevedo et al., 2020;Jiménez-Rivillas et al., 2018;Londoño et al., 2014;Miranda-Esquivel et al., 2004). ...
... Under this criterion, the Páramo province is restricted to Colombia, western Venezuela, Ecuador, and northern Peru (Morrone, 2014(Morrone, , 2015(Morrone, , 2018aJiménez-Rivillas et al., 2018). Some authors (e.g., Díaz-Acevedo et al., 2020;Londoño et al., 2014;Sklenár et al., 2011) consider the Páramo biome, which encompasses other physonomically similar areas from Costa Rica, Panama, and Peru. These areas, although vegetationally similar, harbor different endemic taxa. ...
Some recent contributions to the biogeographic regionalization of the Páramo province are reviewed and compared. As a result, a consensus regionalization is proposed, recognizing 6 subprovinces and 11 districts: Páramos del Norte subprovince (Sierra Nevada district), Cordillera de Mérida Páramo subprovince (Venezuelan Páramo district), Páramos de la Cordillera Oriental subprovince (Páramos de Boyacá and Los Picachos districts), Cordillera Central-Occidental subprovince (Paramillo del Sinú, Santa Inés-Sonsón, Main Central Cordillera and Páramo de los Farallones de Cali districts), Northern Ecuador subprovince (Northern Ecuadorian Páramo district), and Central-Southern Ecuador subprovince (Central Ecuadorian Páramo and Southern Ecuadorian Páramo districts).
... The early Pliocene composition of the páramo (4.7-4.2 Ma) has a clear neotropical signature with Jamesonia/Eriosorus, Huperzia, and Polylepis/Acaena having immigrated to the páramo from lower elevation habitats of the neotropics and subsequently adapted to new environmental conditions (Sklenár et al., 2011). In contrast, the taxa which appear in the record after 3.75 Ma predominantly immigrated to the area from other floristic realms: Sisyrinchium originally occurred in temperate and cool regions of both hemispheres, and Orthrosanthus had a south temperate distribution (Sklenár et al., 2011). ...
... Ma) has a clear neotropical signature with Jamesonia/Eriosorus, Huperzia, and Polylepis/Acaena having immigrated to the páramo from lower elevation habitats of the neotropics and subsequently adapted to new environmental conditions (Sklenár et al., 2011). In contrast, the taxa which appear in the record after 3.75 Ma predominantly immigrated to the area from other floristic realms: Sisyrinchium originally occurred in temperate and cool regions of both hemispheres, and Orthrosanthus had a south temperate distribution (Sklenár et al., 2011). This suggests that the high-elevation ecosystem was first colonized by taxa from proximate habitats of the neotropics, and thereafter, with the progressive formation of the Isthmus of Panama, taxa from more distant locations gradually arrived. ...
The Piacenzian (3.60–2.58 Ma) covers the last stage of the Neogene just before the Earth's climate turned from relatively stable warm conditions to the cooler climate with high amplitude glacial‐interglacial oscillations of the Pleistocene. Even during this period early fluctuations towards cooler conditions occurred, and sea surface temperature (SST) reconstructions show stepwise increasing gradients. The zonal Pacific SST gradient which indicates the strength of the Walker circulation appears to have increased in two steps starting in the Piacenzian. We investigated vegetation and climate change in western equatorial South America under the influence of the Walker circulation and to detect signs for the onset of cooling in the tropics. We studied vegetation changes in western Ecuador using palynological analysis of 88 sediment samples from marine Ocean Drilling Program Site 1239 dated between 3.9 and 2.7 Ma. A general trend towards more open vegetation is observed. The climate changes towards cooler conditions, which is manifested by a lowering of the forest line from 3.3 Ma on. The increase of Amaranthaceae pollen after 3.1 Ma suggests drier conditions along the coast. A comparison with mid‐Piacenzian warm period (mPWP) modeling shows that data and models agree regarding a drier coastal climate during the mPWP. The isochronous occurrence of environmental changes in the presented record, that is, cooling and coastal drying, with the first major pulse of ice‐rafted debris and cooling temperatures in the Northern Hemisphere (between 3.28 and 3.31 Ma) suggests that these changes might have been a precursor of the intensification of the Northern Hemisphere glaciation.
... The high-elevation tropical Andean páramo ecosystem is characterized by rich plant diversity and endemism (Madriñán et al. 2013;Sklenar et al. 2011). Additionally, páramos are hotspots for ecosystems services, including providing water reservoirs, carbon sequestration, irrigation, and rural livelihood improvement (Madriñán et al. 2013). ...
... The genus Puya (Bromeliaceae) comprises conspicuous rosettes widely distributed on the páramos from Costa Rica to northern Argentina and Chile (Sklenar et al. 2011). P. hamata is a rosette that forms locally clumped populations in humid páramos between 3300 and 3700 m asl in Colombia, Ecuador and Peru (Miller and Silander 1991;Schmidt Jabaily and Sytsma 2013). ...
Ecological interactions play a fundamental role in determining the genetic structure of plant species in time and space. The demography of the Andean Puya hamata has been linked to fire regimes and hummingbird behaviour, which might modify the plant’s population genetic structure. Naturally, poor dispersal results in patches of genetically related plants, a pattern intensified further by burning which promotes seedling germination around parent plants. Later, when these plants flower, large patches are attractive to territorial hummingbirds which prevent visits by traplining hummingbird species, carrying pollen from likely unrelated plants. To explore this hypothesis, a genetic study of P. hamata using microsatellite markers was conducted with (i) isolated and grouped adults in two size categories of patches, and (ii) seeds collected from the same patches and isolated individuals. Isolated individual plants presented a higher observed heterozygosity with close to zero inbreeding. Adult plants from large patches showed a lower observed heterozygosity and higher inbreeding than plants from other spatial contexts. Seed genetic structure displayed a gradient of diversity: lower at patch centres but higher at patch edges, in small patches, and for isolated infructescences. The spatial context of these plants, especially the contrast between large patch centres and other situations, determines the genetic diversity of their seeds via hummingbird foraging behaviour. Territorial hummingbirds restrict gene flow in and out of large patches, but traplining hummingbirds maintain genetic diversity among isolated plants, small patches, and plants at the edges of large patches. Our study illustrates the need to consider interactions between land use, plants, and their pollinators when considering genetic diversity at the landscape scale.
... Limited to elevations above 3,000 m, páramo is patchily distributed among the many higher peaks and volcanos in the range. Páramo contains a high number of endemic species, which are mostly are restricted to small elevational ranges (above 2,800 m; Luteyn, 1999;Sklenář, Dušková & Balslev, 2011;Madriñán, Cortés & Richardson, 2013;Sklenář, Hedberg & Cleef, 2014). Habitat loss due to various anthropogenic impacts is a major concern for the conservation of this ecosystem (Hofstede et al., 2002), but little consensus has emerged on the effects of habitat isolation on diversification of this region's biota. ...
... The Pallatanga fault, a prominent NE-SW strike-slip fault crossing the western cordillera (Baize et al., 2015), may also affect lineage dispersal. The most prominent geographic divide considered in this study was the split of the Ecuadorian Andes into east and west cordilleras, associated with limits of distribution in several vertebrate and plant species (Chaves et al., 2007;Guayasamin et al., 2010;Sklenář, Dušková & Balslev, 2011). ...
Background:
Páramo is a tropical alpine ecosystem present in the northern Andes. Its patchy distribution imposes limits and barriers to specialist inhabitants. We aim to assess the effects of this habitat distribution on divergence across two independently flightless ground beetle lineages, in the genera Dyscolus and Dercylus.
Methods:
One nuclear and one mitochondrial gene from 110 individuals from 10 sites across the two lineages were sequenced and analyzed using a combination of phylogenetics, population genetic analyses, and niche modeling methods.
Results:
The two lineages show different degrees of population subdivision. Low levels of gene flow were found in Dyscolus alpinus, where one dominant haplotype is found in four out of the six populations analyzed for both molecular markers. However, complete population isolation was revealed in species of the genus Dercylus, where high levels of differentiation exist at species and population level for both genes. Maximum entropy models of species in the Dercylus lineage show overlapping distributions. Still, species distributions appear to be restricted to small areas across the Andes.
Conclusion:
Even though both beetle lineages are flightless, the dispersal ability of each beetle lineage appears to influence the genetic diversity across fragmented páramo populations, where Dyscolus alpinus appears to be a better disperser than species in the genus Dercylus.
... Los hábitats de alta elevación, como páramos y punas, se encuentran a lo largo de la cadena de los Andes desde Venezuela hasta Bolivia. Son hábitats ricos en especies de plantas (como el frailejón), así como en mamíferos (como el oso de anteojos), lagartos, aves, e insectos polinizadores (Sklenař et al., 2011). Los lagos de la puna soportan hasta 58 especies de peces nativos (Vila et al., 2007), así como importantes ensamblajes de insectos y microrganismos (Costello et al., 2009;Schmidt et al., 2009). ...
... Los hábitats de alta elevación, como páramos y punas, se encuentran a lo largo de la cadena de los Andes desde Venezuela hasta Bolivia. Son hábitats ricos en especies de plantas (como el frailejón), así como en mamíferos (como el oso de anteojos), lagartos, aves, e insectos polinizadores (Sklenař et al., 2011). Los lagos de la puna soportan hasta 58 especies de peces nativos (Vila et al., 2007), así como importantes ensamblajes de insectos y microrganismos (Costello et al., 2009;Schmidt et al., 2009). ...
La región de América Latina y el Caribe (ALC) es especialmente rica en biodiversidad. Con cerca del 16% de la superficie terrestre alberga el 50% de la diversidad biológica del planeta. Además, es una región privilegiada en oferta hídrica, con cerca de la tercera parte del potencial mundial. Esta biodiversidad sustenta a los ecosistemas naturales que proveen servicios de aprovisionamiento, regulación y culturales fundamentales para el bienestar de la sociedad. Sin embargo, estos ecosistemas se encuentran bajo amenaza debido, principalmente, a la transformación de hábitats, la contaminación, el cambio climático, las invasiones biológicas y la sobreexplotación. A la vez, los sistemas de gobernanza, el desarrollo económico y tecnológico, las tendencias demográficas, y fallas en las políticas tienden a agravar estas presiones. Desde el punto de vista económico, estos impactos se asocian a tres fallas de mercado: problemas de derechos de propiedad, externalidades y problemas de información. Este documento presenta una caracterización de la biodiversidad en ALC, destacando su estado actual, importancia y amenazas; adicionalmente, presenta un conjunto de políticas que han sido diseñadas y aplicadas para contribuir a la conservación de la biodiversidad y a su uso sostenible, con énfasis en tres sectores claves: turismo, pesca y agua. Un segundo documento complementa esta información con un análisis del valor económico de la biodiversidad en la región.
... The tropical Andes constitute one of the most important areas of endemism on a global scale, but at the same time, one of the most threatened and least studied (Myers et al. 2000;Orme et al. 2005;Godoy-Bürki et al. 2014). The southern part of the central Andes is located in the centre of the arid diagonal of South America, and its flora has been less studied than that of the more humid regions, such as the southern Andes (Kier et al. 2005;Sklenář et al. 2011) and the northern Andes (Arroyo et al. 1999(Arroyo et al. , 2004Rodríguez-Cabral et al. 2008). ...
The South American central Andes have a great richness of Asteraceae, where the genus Stevia (Eupatorieae, Piqueriinae) is also especially diverse. The taxonomy of Stevia species in the southern part of the central Andes pose a challenge because of the unclear delimitation among the species and overlap of morphological characters. Two species complexes were identified for the region comprising north Argentina and southern Bolivia. In this study, our objectives were to employ morphometric analyses to assess the delimitation of taxa within the Stevia alpina Griseb. and Stevia chamaedrys Griseb. complexes. We aimed to identify informative morphological characters and gain insight into the identity of species in each group. To accom plish this, we utilised cluster analysis, principal-component analysis, non-metric multidimensional scaling and univariate analyses to evaluate 37 morphological traits. In total, 200 specimens were examined, covering the entire geographic distribution of each species complex. We found support for the recognition of nine species: Stevia alpina, S. breviaristata Hook. & Arn., S. chamaedrys, S. mandonii Sch.Bip., S. mercedensis Hieron., S. minor Griseb., S. potrerensis Hieron., S. procumbens Hieron. and S. vaga Griseb. A new combination and status is proposed for S. tarijensis Hieron., incorporating it as a variety of S. mandonii, and S. centinelae Cabrera and S. crassicephala Cabrera are merged as synonyms under the name S. alpina. Two neotypes are designated for the names S. mercedensis and S. potrerensis.
... Endemism is slightly higher while species turnover is lower in the Afroalpine than in the Páramo (Sklenář et al., 2014). Previous research comparing tropical alpine regions has focused on current area size, isolation, and source areas of colonization to explain the differences between the Páramo and the Afroalpine (Sklenář et al., 2011(Sklenář et al., , 2014Gehrke & Linder, 2014;Gehrke, 2018). The larger area and lower degree of isolation found in the Páramo compared to the Afroalpine have been used to explain the higher species diversity of the Páramo. ...
Habitat stability is important for maintaining biodiversity by preventing species extinction, but this stability is being challenged by climate change. The tropical alpine ecosystem is currently one of the ecosystems most threatened by global warming, and the flora close to the permanent snow line is at high risk of extinction. The tropical alpine ecosystem, found in South and Central America, Malesia and Papuasia, Africa, and Hawaii, is of relatively young evolutionary age, and it has been exposed to changing climates since its origin, particularly during the Pleistocene. Estimating habitat loss and gain between the Last Glacial Maximum (LGM) and the present allows us to relate current biodiversity to past changes in climate and habitat stability. In order to do so, (i) we developed a unifying climate‐based delimitation of tropical alpine regions across continents, and (ii) we used this delimitation to assess the degree of habitat stability, that is, the overlap of suitable areas between the LGM and the present, in different tropical alpine regions. Finally, we discuss the link between habitat stability and tropical alpine plant diversity. Our climate‐based delimitation approach can be easily applied to other ecosystems using our developed code, facilitating macro‐comparative studies of habitat dynamics through time.
... These clades may have subsequently dispersed south along the already-formed Andean chain. The contribution of the northern-temperate flora to the current composition of high-elevation Andean ecosystems has been discussed by several previous studies (Sklenář et al., 2011;Simpson, 1975;Bacon et al., 2018). Notably, the plant genus Lupinus (Fabaceae) arrived to the Andes from North America and then radiated, demonstrating extremely high rates of speciation and morphological change over a very short time period (1.18-1.76 ...
Geological events such as mountain uplift affect how, when, and where species diversify, but measuring those effects is a longstanding challenge. Andean orogeny impacted the evolution of regional biota by creating barriers to gene flow, opening new habitats, and changing local climate. Bomarea (Alstroemeriaceae) are tropical plants with (often) small, isolated ranges; in total, Bomarea species occur from central Mexico to central Chile. This genus appears to have evolved rapidly and quite recently, and rapid radiations are often challenging to resolve with traditional phylogenetic inference. In this study, we apply phylogenomics—with hundreds of loci, gene-tree-based data curation, and a multispecies-coalescent approach—to infer the phylogeny of Bomarea. We used this phylogeny to untangle the potential drivers of diversification and biogeographic history. In particular, we test if Andean orogeny contributed to the diversification of Bomarea. We find that Bomarea originated in the central Andes during the mid-Miocene, then spread north, following the trajectory of mountain uplift. Furthermore, Andean lineages diversified faster than non-Andean relatives. Bomarea thus demonstrates that—at least in some cases—geological change rather than environmental stability has driven high species diversity in a tropical biodiversity hotspot. These results also demonstrate the utility (and danger) of genome-scale data for making macroevolutionary inferences.
... In general, the 16 bofedales of the Chimborazo Fauna Production Reserve present a similar number of species. with a total of (63 vascular, 12 bryophytes, and 4 pteridophytes) and 1 lichen, belonging to 64 genera and 35 families; a pattern typical of Andean paramos that are characterized by a floristic diversity richer in species than that of any other tropicalalpine ecosystem [60][61][62]. ...
The bofedales are high Andean ecosystems of great socioeconomic and ecological importance. The Chimborazo Fauna Production Reserve has 15 bofedales in its jurisdiction, located in the provinces of Chimborazo, Bolívar, and Tungurahua. The objective of this study was to establish the relationship between plant species composition and the physicochemical characteristics of water and soil. To determine the floristic composition, destructive sampling of species was applied, and three sampling points of 1 m2 were established every 100 m per wetland. At each sampling point, physical-chemical variables were recorded in situ and in the laboratory for water and soil. The floristic analysis identified 78 riparian species of riparian plants (63 vascular, 12 bryophytes, 4 pteridophytes) and 1 lichen. In the aquatic environment, seven vascular plants, recognized as macrophytes, were recorded. The results show great heterogeneity in the soil, water, and vegetation characters because they respond to a mineralization gradient (as indicated by the high values of electrical conductivity and dissolved ions). Additionally, it was observed that the total amount of soluble solids that characterizes the Los Hieleros wetland (W11) is independent of hardness and chemical oxygen demand, which correlate with each other and, in turn, better describe the Pachancho wetland (W12). The highest degree of turbidity corresponds to the Cóndor Samana (W9) and Portal Andino (W10) wetlands. The Culebrillas (W6), Puente Ayora ANI (W14), and Pampas Salasacas (W1) wetlands are characterized by the presence of dissolved oxygen, so it is assumed that these are the wetlands with the best water quality. Consequently, it is imperative to double efforts to describe the ecology and status of these high Andean wetlands in order to promote their conservation.
... Antennaria and Erigeron) whereas those that are apomictic in the Southern Hemisphere have mostly Austral-Antarctic southern temperate distributions (e.g. Acaena ovalifolia and Cortaderia sericantha; Sklenář et al. 2011). The regional differences in the proportion of apomicts between the alpine floras become more apparent (and significant) when only the typical apomictic families are considered. ...
Apomictic plants mostly occur at higher latitudes and higher elevations, where they tend to occupy deglaciated areas. By analysing samples of the alpine floras of different latitudinal zones of the Americas (Argentina, Bolivia, Ecuador, USA), we investigated whether the proportion of gametophytic apomixis is comparable between the temperate alpine zones of the Northern Hemisphere and the Southern Hemisphere and whether the proportion of apomictic species increases from the alpine tropics towards the temperate alpine zone.
The reproductive systems of 196 species and 275 individuals were determined by a flow-cytometric seed screening of 999 seeds. Phylogenetic logistic regression was used to evaluate differences in the proportion of apomictic species in samples of regional alpine floras.
The apomictic embryo:endosperm ratio was determined for 33 species (two pseudogamous species and 31 species with autonomous apomixis) belonging to 28 genera of 13 families. The probability of a species being apomictic did not significantly differ between the regions. The highest probability of a species being apomictic was estimated for the northern temperate zone (29.6%), followed by the tropical zone (12.5%), and the southern temperate zone (11.9%).
Our results show that asexual plant reproduction by apomixis is not restricted to the alpine zone of the Northern Hemisphere and its representation in alpine floras of the Southern Hemisphere, including the alpine tropics, has been substantially underestimated.
... This speciation was caused by the retraction and dispersion of the genera during periods of isolation (Simpson and Todzia, 1990). The composition of páramo's original flora is neotropical and characterized by species coming from temperate areas of both hemispheres with a greater contribution from the northern hemisphere (Sklenář et al., 2011). Volcanism also played an important role in the formation, population and distribution of ecosystems in the Andes (Sklenář et al., 2010;Salamanca, 1992). ...
The Ecuadorian páramo ecosystems play an important role in providing the local population with drinking water, irrigation, hydropower generation, carbon storage, and agricultural production. In Ecuador, páramo vegetation has suffered significant degradation and loss due to land use change. This has had a major impact on the capability of the ecosystems to resist or adapt to external pressures such as climate change. This research aims to understand the effects of climate change on the Ecuadorian páramo ecosystems and the potential consequences on the ecosystem services they provide. This study applies state-of-the-art techniques to evaluate: a) the impact of climate change on the climatic niche distribution of the páramo ecosystems based on future greenhouse gas concentration scenarios; b) the amount of carbon stored in both soil and vegetation for key types of páramo ecosystems; and c) the future exposure of the Ecuadorian páramos to land use pressures, considering climate as a determining factor for increases or decreases in the farming frontier. The research show that in 30 (2050) to 50 (2070) years, páramo ecosystems with isolated or restricted distribution could suffer significant niche contraction (>60%) or niche extinction (100%), while ecosystems with a broad distribution seem less vulnerable (<60%). The carbon (C) estimates show that C in soils could vary from 87.7 to 278.9 ton C/ha, while in vegetation could range from 5.3 to 8.9 ton C/ha in grassland and shrubland vegetation, and 96.3±32.4 ton C/ha in forest. Soil C stock is influenced by altitude and climatic conditions such as precipitation and temperature. The farming frontier could increase in 23% (2050) to 35% (2070) towards and within the páramo areas, most of them occurring in areas without protection (16%-21%). This study reveals considerable challenges for the future of the Ecuadorian páramo, highlighting the need to implement adaptation strategies in these natural areas.
... Because of their relevance to the water cycle, páramo ecosystems have been widely studied (Hofstede, 2003;Sarmiento et al., 2013;Sklenar et al., 2010;van der Hammen & Cleef, 1986). The Andean páramos comprise a large variety of lakes, peat bogs, and wet grasslands where the soil can be up to several meters thick (Buytaert et al., 2006). ...
The Colombian Andean Mountains include the headwaters of the main basins of the country. However, the isotope composition of water in these high mountain ecosystems has been poorly studied. In this study, we analysed the first set of stable isotope data collected along a wide elevation range (2600–4950 m a.s.l.) in the Central Andes of Colombia. The stable isotope composition of stream water and precipitation was determined for a period between 2017 and 2018 in the Upper Claro River basin. The driving factors influencing the spatial and temporal variability of δ ² H, δ ¹⁸ O, and d‐excess were identified, and compared with daily air temperature and precipitation data from seven meteorological stations. The local regression line was described by δ ² H = 8.2 δ ¹⁸ O + 12.3, R ² = 0.98. The δ ² H and δ ¹⁸ O values showed more depletion in heavy isotopes, and the d‐excess values were more negative during the rainy season. An altitude effect of −0.11‰/100 m and −0.18‰/100 m was estimated for stream water and precipitation δ ¹⁸ O values, respectively, with the latter showing non‐linear behaviour. The dataset was compared with Colombian stations of the Global Network of Isotopes in Precipitation database, and a back‐trajectory analysis of air masses was conducted and compared with the d‐excess values. The δ ¹⁸ O weighted mean values changed with respect to the position in the Central Andes, indicating contrasting altitude effects depending on the moisture sources. The most positive d‐excess values were attributed to moisture recycling enhanced by local ecosystem conditions and the origin of precipitation from the Amazon basin, which change during the year and across the northern Andes. The results showed a high level of variation because of differences in elevation, seasonality, and atmospheric circulation patterns during the year. This study contributes to knowledge of spatial and temporal isotope composition data in the northern Andes, delineation of water supply basins, and to the definition of ecosystem boundaries in the high mountains of Colombia.
... High-elevation habitats in the Americas are thus suitable for examining latitudinal TTB patterns in plants. The American Cordilleras enabled exchanges of plant lineages across latitudes and numerous migrations occurred from higher latitudes to the tropics once the equatorial Andes reached sufficient elevation in the Plio/Pleistocene (Sklenář et al., 2011;van der Hammen & Cleef, 1986). The lineages migrating into the alpine tropics from thermally seasonal latitudes are often believed to be physiologically preadapted, particularly considering their temperature niche (Donoghue, 2008;Gehrke, 2018), although this assumption has been rarely tested (Nürk et al., 2018). ...
Aim
Tolerance of species to extreme temperatures largely determines their distribution and vulnerability to climate change. We examined thermal tolerance in tropical and temperate alpine plants, testing the hypotheses that: (a) temperate plants are resistant to more extreme temperatures and have an overall wider thermal tolerance breadth (TTB); (b) TTB in temperate plants is wider than TTB in tropical plants during the entire growing season; (c) resistance to frost and heat varies during the season in temperate plants but not in tropical plants; (d) TTB of a species predicts its latitudinal range.
Location
Tropical (Ecuador, Bolivia) and temperate (USA, Austria) mountains.
Time period
Four periods of the growing season (2014, 2016–2019).
Major taxa
Ninety‐six vascular plant species.
Methods
We employed the electrolyte leakage method to estimate the temperature resistance, that is, the temperature at which 50% tissue injury (Lt50) occurs in leaves. We used phylogenetic linear mixed‐effect models in a Bayesian framework to test for differences between the plant groups.
Results
Temperate and tropical plants do not differ in their temperature resistance. The four hypotheses are rejected since: (a) temperate plants do not have significantly wider overall TTB compared to tropical plants, (b) TTB of temperate plants is wider than TTB of tropical plants only at the end of the temperate summer, (c) seasonal acclimation is observed in both plant groups, (d) the latitudinal range of the plants is not related to TTB.
Main conclusions
The lack of TTB differences between temperate and tropical alpine plants is consistent with trends observed in ectothermic animals, which suggests a general latitudinal pattern in high‐elevation poikilotherm organisms. Limited acclimation capacity to cope with long freezing exposures restricts the occurrence of tropical alpine species to thermally aseasonal environments making them particularly vulnerable to climate change.
... In the Apiaceae, the evolution of pentaploid endosperm (5n) may have facilitated the colonization of alpine habitats following the environmental changes that took place at the turn of the Miocene and Pleistocene (Simpson and Todzia 1990;Testolin et al. 2021), and that enabled members of the genus Azorella to become some of the most dominant species of alpine vegetation in the Andes. The South American genus Gunnera shares with Azorella a partially similar history of colonizing South America (Sklenář et al. 2011;Nicolas and Plunkett 2012;Fernández et al. 2017a) and shares the same Penaeatype embryo sac (Virkki 1962;Wilkinson and Wanntorp 2007), supporting the idea of convergence towards higher endosperm ploidy in harsh environments. ...
About 80% of angiosperms form a monosporic Polygonum-type embryo sac, whereas in the remaining species, eleven other types of embryo sac are found. Evidence as to the type of embryo sac is lacking for many plant species, and the role of higher-ploidy endosperm is unknown. In contrast to the rest of the Apiaceae, where a Polygonum-type embryo sac (3n endosperm) has been reported, the few species of the Azorelloideae studied to form a Drusa-type embryo sac (3n endosperm) or a Penaea-type embryo sac (5n endosperm). This variation within Azorelloideae makes this subfamily, and its genus Azorella in particular, a good candidate for studying the evolutionary importance of the embryo sac and endosperm in diversification. We studied the variation in the type of embryo sac and the ploidy level of the endosperm in Andean-Patagonian Azorella and closely related Pozoa on a sample of 101 individuals from 31 populations of 21 species. We employed flow cytometric seed screening and calibrated the results of ploidy level estimation against embryological observations. In addition, we examined the genome size variation of the species sampled. All species of Azorella formed Penaea-type embryo sacs and a pentaploid endosperm, whereas one species of Pozoa formed triploid and the other tetraploid endosperms. Variations in the type of embryo sac and endosperm ploidy have probably shaped the evolution of the different lineages of Azorelloideae in the southern Andes. A Penaea-type embryo sac, which represents a likely synapomorphy of Azorella, is a feature of underestimated significance in the evolution of angiosperms.
... Lupinus and Pentacalia (40). Such large in situ species radiations are virtually absent from the afroalpine 233 flora, probably reflecting the much smaller spatial extent and greater fragmentation of the tropical alpine 234 habitat in Africa. ...
Significance
Resilience is required to withstand or mitigate the effect of human-induced climate change. Today whole ecosystems are affected by climate change, but our understanding of their evolution and natural response is limited, often restricted to individual populations or species. The enigmatic flora on the tops of the African sky islands is isolated and unique, showing striking adaptations to the harsh tropical alpine conditions. Here we analyze genome data from a large fraction of afroalpine plants and show that this remarkable flora has a dynamic history with frequent colonizations and extinctions, most likely caused by previous natural climate changes during the ice-age cycles. The flora will be particularly vulnerable to human-induced climate warming, reducing alpine habitat into successively smaller areas.
... In the Apiaceae, the evolution of pentaploid endosperm (5n) may have facilitated the colonization of alpine habitats following the environmental changes that took place at the turn of the Miocene and Pleistocene (Simpson and Todzia 1990;Testolin et al. 2021), and that enabled members of the genus Azorella to become some of the most dominant species of alpine vegetation in the Andes. The South American genus Gunnera shares with Azorella a partially similar history of colonizing South America (Sklenář et al. 2011;Nicolas and Plunkett 2012;Fernández et al. 2017a) and shares the same Penaeatype embryo sac (Virkki 1962;Wilkinson and Wanntorp 2007), supporting the idea of convergence towards higher endosperm ploidy in harsh environments. ...
About 80% of angiosperms form a monosporic Polygonum -type embryo sac whereas in the remaining species eleven other types of embryo sac are found. Evidence as to the type of embryo sac is lacking for many plant species, and the role of higher-ploidy endosperm is unknown. In contrast to the rest of the Apiaceae, where a Polygonum -type embryo sac (3n endosperm) has been reported, the few species of the Azorelloideae studied form a Drusa- type embryo sac (3n endosperm) or a Penaea -type embryo sac (5n endosperm). This variation within Azorelloideae makes this subfamily, and its genus Azorella in particular, a good candidate for studying the evolutionary importance of the embryo sac and endosperm in diversification. We studied the variation in the type of embryo sac and the ploidy level of the endosperm in Andean-Patagonian Azorella and closely related Pozoa on a sample of 101 individuals from 31 populations of 21 species. We employed flow cytometric seed screening and calibrated the results of ploidy level estimation against embryological observations. In addition, we examined the genome size variation of the species sampled. All species of Azorella formed Penaea -type embryo sacs and a pentaploid endosperm whereas one species of Pozoa formed triploid and the other tetraploid endosperms. Variations in the type of embryo sac and endosperm ploidy have probably shaped the evolution of the different lineages of Azorelloideae in the southern Andes. A Penaea -type embryo sac, which represents a likely synapomorphy of Azorella , is a feature of underestimated significance in the evolution of angiosperms.
... The páramo of the northern Andes is one of the most diverse tropical alpine floras in the world (Sklenář et al. 2011;Madriñán et al. 2013). Extensive paleoenvironmental research has shown that the páramo underwent dynamic elevational shifts during the Pleistocene climate fluctuations (e.g., van der Hammen and Cleef 1986;Hooghiemstra and van der Hammen 2004;Groot et al. 2011;Flantua and Hooghiemstra 2018;Flantua et al. 2019). ...
The role of Pleistocene climate change in shaping patterns of genetic and species diversity has been widely demonstrated. However, tropical mountains remain less explored. In the northern Andes, distributional shifts of the vegetation during the Pleistocene are believed to have promoted plant diversification. In this regard, the role of gene flow and geographic isolation has been intensively debated. Here, we use a population genetic approach, microsatellite markers, and Bayesian statistics to assess the impact of Pleistocene climate change on intraspecific patterns of gene flow and genetic variation, and on the demographic history of the populations. We study Lupinus microphyllus, which belongs to a clade of Andean Lupinus species that has emerged as a model group in studies of plant diversification. We detect signatures of historical gene flow and negligible contemporary gene flow between populations. We find very low within-population genetic diversity and signals of an ancient decline in population size that may be lasting until today. We conclude that, in spite of periods of increased connectivity and gene flow, intraspecific genetic differentiation is mainly driven by periods of geographic isolation, restricted gene flow, and genetic drift. The intraspecific genetic pattern of high-elevation Andean plant species has been also shaped by local environmental factors, such as volcanic activity or glacier coverage, and by species-specific traits, such as the reproductive and dispersal strategies.
... The family Asteraceae is one of the youngest and most speciesrich families among the angiosperms and accounts for a large diversity within tropical alpine ecosystems (Sklenář et al., 2011;Panero and Crozier, 2016). WGD events and hybridization are common for many members of the Asteraceae (Smissen et al., 2011;Galbany-Casals et al., 2014;Barker et al., 2016;Huang et al., 2016;Zhang et al., 2021). ...
A major challenge in phylogenetics and -genomics is to resolve young rapidly radiating groups. The fast succession of species increases the probability of incomplete lineage sorting (ILS), and different topologies of the gene trees are expected, leading to gene tree discordance, i.e., not all gene trees represent the species tree. Phylogenetic discordance is common in phylogenomic datasets, and apart from ILS, additional sources include hybridization, whole-genome duplication, and methodological artifacts. Despite a high degree of gene tree discordance, species trees are often well supported and the sources of discordance are not further addressed in phylogenomic studies, which can eventually lead to incorrect phylogenetic hypotheses, especially in rapidly radiating groups. We chose the high-Andean Asteraceae genus Loricaria to shed light on the potential sources of phylogenetic discordance and generated a phylogenetic hypothesis. By accounting for paralogy during gene tree inference, we generated a species tree based on hundreds of nuclear loci, using Hyb-Seq, and a plastome phylogeny obtained from off-target reads during target enrichment. We observed a high degree of gene tree discordance, which we found implausible at first sight, because the genus did not show evidence of hybridization in previous studies. We used various phylogenomic analyses (trees and networks) as well as the D-statistics to test for ILS and hybridization, which we developed into a workflow on how to tackle phylogenetic discordance in recent radiations. We found strong evidence for ILS and hybridization within the genus Loricaria. Low genetic differentiation was evident between species located in different Andean cordilleras, which could be indicative of substantial introgression between populations, promoted during Pleistocene glaciations, when alpine habitats shifted creating opportunities for secondary contact and hybridization.
... 22 species, excluding Lesquerella taxa) in montane and higher elevation regions have a vast and complex genomic history, reflected by polyploidy (Rollins 1993 and references therein), neopolyploidization events, and variable genome sizes (Fuentes-Soriano 2010;Hohmann et al. 2015). Perhaps the genomic events may have conferred higher adaptability and increased tolerance to these environments, thus facilitating species radiation (Jordon-Thaden and Koch 2008;Sklen ar et al. 2011;Karl and Koch 2013). Further molecular data and more complete sampling of species of Physaria s. s. with n 5 4, 5 (ca. ...
Physarieae is a small tribe of herbaceous annual and woody perennial mustards that are mostly endemic to North America, with its members including a large amount of variation in floral, fruit, and chromosomal variation. Building on a previous study of Physarieae based on morphology and ndhF plastid DNA, we reconstructed the evolutionary history of the tribe using new sequence data from two nuclear markers, and compared the new topologies against previously published cpDNA-based phylogenetic hypotheses. The novel analyses included ca. 420 new sequences of ITS and LUMINIDEPENDENS ( LD ) markers for 39 and 47 species, respectively, with sampling accounting for all seven genera of Physarieae, including nomenclatural type species, and 11 outgroup taxa. Maximum parsimony, maximum likelihood, and Bayesian analyses showed that these additional markers were largely consistent with the previous ndhF data that supported the monophyly of Physarieae and resolved two major clades within the tribe, i.e., DDNLS ( Dithyrea , Dimorphocarpa , Nerisyrenia , Lyrocarpa , and Synthlipsis )and PP ( Paysonia and Physaria ). New analyses also increased internal resolution for some closely related species and lineages within both clades. The monophyly of Dithyrea and the sister relationship of Paysonia to Physaria was consistent in all trees, with the sister relationship of Nerisyrenia to Lyrocarpa supported by ndhF and ITS, and the positions of Dimorphocarpa and Synthlipsis shifted within the DDNLS Clade depending on the employed data set. Finally, using the strong, new phylogenetic framework of combined cpDNA + nDNA data, we discussed standing hypotheses of trichome evolution in the tribe suggested by ndhF .
... One way this may have occurred is through 'mountainhopping' (Knox & Palmer, 1995, 1998Sklenář et al., 2014), whereby colonizers could have sequentially colonized adjacent mountains, leading to island-like diversification. Although evidence of this has been found in species occupying highelevation páramo environments (Raven, 1963;Hughes & Eastwood, 2006;Moore & Donoghue, 2007;Bone et al., 2011;Sklenář et al., 2011;Luebert & Weigend, 2014), few studies have tested this hypothesis in lineages that occupy lower elevational bands in the Andes, which are presumably less insular (Kelly et al., 1994). ...
Recent studies have demonstrated that ecological processes that shape community structure and dynamics change along environmental gradients. However, much less is known about how the emergence of the gradients themselves shape the evolution of species that underlie community assembly. In this study, we address how the creation of novel environments leads to community assembly via two nonmutually exclusive processes: immigration and ecological sorting of pre‐adapted clades (ISPC), and recent adaptive diversification (RAD). We study these processes in the context of the elevational gradient created by the uplift of the Central Andes.
We develop a novel approach and method based on the decomposition of species turnover into within‐ and among‐clade components, where clades correspond to lineages that originated before mountain uplift. Effects of ISPC and RAD can be inferred from how components of turnover change with elevation. We test our approach using data from over 500 Andean forest plots.
We found that species turnover between communities at different elevations is dominated by the replacement of clades that originated before the uplift of the Central Andes.
Our results suggest that immigration and sorting of clades pre‐adapted to montane habitats is the primary mechanism shaping tree communities across elevations.
... Landscape change is recognized as a major driver of lineage diversification (Hoorn et al., 2013). In the Neotropics, the most species-rich region in the world, the uplift of the Andean cordillera not only contributed directly and indirectly to the assembly of the terrestrial biota (Janzen, 1967;Kattan et al., 2004;Antonelli et al., 2009;Antonelli & Sanmart ın, 2011;Sklen a r et al., 2011;Smith et al., 2014;Hoorn et al., 2018;Quintero & Jetz, 2018), but also impacted the evolution of riverine organisms by shifting the physical locations of watersheds (Albert et al., 2006(Albert et al., , 2020Albert & Crampton, 2010;Picq et al., 2014;Tagliacollo et al., 2015;Ruokolainen et al., 2019). Andean uplift played a major role in the diversification of terrestrial plants in the Neotropics (Hughes & Eastwood, 2006;Madriñ an et al., 2013;N€ urk et al., 2013;Lagomarsino et al., 2016;P erez-Escobar et al., 2017;Richardson et al., 2018;Testo et al., 2019). ...
Northern South America is a geologically dynamic and species‐rich region. Fossil and stratigraphic data show that mountain uplift in the tropical Andes reconfigured river drainages. These landscape changes shaped the evolution of the flora in the region, yet the impacts on aquatic taxa have been overlooked.
We explore the role of landscape change on the evolution of plants living strictly in rivers across drainage basins in northern South America by conducting population structure, phylogenetic inference, and divergence‐dating analyses for two species in the genus Marathrum (Podostemaceae).
Mountain uplift and drainage basin formation isolated populations of M. utile and M. foeniculaceum in northern South America and created barriers to gene flow across river drainages. Sympatric species hybridize and the hybrids show the phenotype of one parental line. We propose that the pattern of divergence of populations reflects the formation of river drainages, which was not complete until < 4.1 million yr ago (Ma).
Our study provides a clear picture of the role of landscape change on the evolution of plants living strictly in rivers in northern South America. By shifting the focus to aquatic taxa, we provide a novel perspective on the processes shaping the evolution of the Neotropical flora.
... Consequently, Holarctic alpine vegetation shares many species with the Arctic (Billings, 1974) and has major links with Afrotropical alpine species (Linder, 2014;Carbutt & Edwards, 2015). In contrast, a large part of Neotropical alpine plants originated locally through migration and adaptation of Neotropical lowland species (Sklenář et al., 2011), some of which also contributed to Afrotropical lineages (Linder, 2014). Finally, the functional similarity of the Neotropics and Australasia probably derived from both migration (Raven & Axelrod, 1972) and convergent evolu- ...
Questions
What are the functional trade‐offs of vascular plant species in global alpine ecosystems? How is functional variation related to vegetation zones, climatic groups and biogeographic realms? What is the relative contribution of macroclimate and evolutionary history in shaping the functional variation of alpine plant communities?
Location
Global.
Methods
We compiled a data set of alpine vegetation with 5,532 geo‐referenced plots, 1,933 species and six plant functional traits. We used principal component analysis to quantify functional trade‐offs among species and trait probability density to assess the functional dissimilarity of alpine vegetation in different vegetation zones, climatic groups and biogeographic realms. We used multiple regression on distance matrices to model community functional dissimilarity against environmental and phylogenetic dissimilarity, controlling for geographic distance.
Results
The first two PCA axes explained 66% of the species’ functional variation and were related to the leaf and stem economic spectra, respectively. Trait probability density was largely independent of vegetation zone and macroclimate but differed across biogeographic realms. The same pattern emerged for both species pool and community levels. The effects of environmental and phylogenetic dissimilarities on community functional dissimilarity had similar magnitude, while the effect of geographic distance was negligible.
Conclusions
Plant species in alpine areas reflect the global variation of plant function, but with a predominant role of resource use strategies. Current macroclimate exerts a limited effect on alpine vegetation, mostly acting at the community level in combination with evolutionary history. Global alpine vegetation is functionally unrelated to the vegetation zones in which it is embedded, exhibiting strong functional convergence across regions.
... mollis (Fig. 4, habit). Some studies demonstrate that the evolution of some shrub lineages to subshrubs may occur as an in situ adaptation to high-elevation climate conditions, as in different groups that occur on the Andean páramo (Sklenář et al., 2011), but this needs further investigation. This apparently also occurred in other clades in core Melastomateae, such as Heterocentron and allies and Monochaetum and allies. ...
In the past decade, several phylogenetic studies based on molecular data have been generated and changed our view on the evolutionary history and classification of Melastomataceae. Nonetheless, given the size of the family, some groups are still under-sampled and poorly understood, such as the clade formed by Brachyotum and allies in Melastomateae, including three genera, Andesanthus, Brachyotum and Chaetogastra. The principal objective of this work was to further test the relationships in this clade by increasing taxon and locus sampling and by including morphological character reconstructions. In this study, we included nuclear (nrITS, nrETS and waxy) and plastid sequences (accD-psaI, psbK-psbL, trnS-trnG) from 129 species and 29 genera of Melastomataceae, corresponding to c. 46.5% of the species belonging to the clade, and that were used to build phylogenetic hypotheses. We also estimated the evolution of 23 morphological characters through ancestral state reconstruction and the elevational ranges of the species. Our results recovered two major clades: (1) Brachyotum, with species traditionally recognized in Brachyotum, but also including a few species traditionally recognized in Tibouchina; and (2) Chaetogastra, with most species traditionally recognized in Tibouchina, mainly from Tibouchina sections Pseudopterolepis, Diotanthera, Simplicicaules and Purpurella. Andesanthus was placed as sister to Brachyotum and allies in previous phylogenetic analyses; however, in this study it has been recovered as sister to the clades formed by Heterocentron and allies, Monochaetum and allies, and Brachyotum and allies. Four morphological characters can be useful to distinguish genera and clades among Brachyotum and allies: habit; flower position; the angle formed by the petals in relation to the hypanthium; and stamen arrangement. We also find that species in the Brachyotum clade occur at higher elevations (1500–4700 m) than Chaetogastra spp. (sea level to c. 3200 m, but more common at lower elevations, c. 600 to 1800 m). Based on all this evidence we propose the maintenance of Brachyotum as a genus segregated from the recently reinstated Chaetogastra. This work is a contribution to the systematics of Melastomateae, with an improvement in the resolution of the trees in relation to previous phylogenetic analyses, indicating that subclades have a strong relationship with geographical distribution.
... [Asteraceae] (Sklenář et al., 2011;Kolář et al., 2016), and Senecio L. ...
PREMISE: Events of accelerated species diversification represent one of Earth’s most celebrated evolutionary outcomes. Northern Andean high-elevation ecosystems, or páramos, host some plant lineages that have experienced the fastest diversification rates, likely triggered by ecological opportunities created by mountain uplifts, local climate shifts, and key trait innovations. However, the mechanisms behind rapid speciation into
the new adaptive zone provided by these opportunities have long remained unclear. METHODS: We address this issue by studying the Venezuelan clade of Espeletia, a species rich group of páramo-endemics showing a dazzling ecological and morphological diversity. We performed several comparative analyses to study both lineage and trait diversification, using an updated molecular phylogeny of this plant group. RESULTS: We showed that sets of either vegetative or reproductive traits have conjointly diversified in Espeletia along different vegetation belts, leading to adaptive syndromes. Diversification in vegetative traits occurred earlier than in reproductive ones. The rate of species and morphological diversification showed a tendency to slow down over time, probably due to diversity dependence. We also found that closely related species exhibit significantly more overlap in their geographic distributions than distantly related taxa, suggesting that most events of ecological divergence occurred at close geographic proximity within páramos. CONCLUSIONS: These results provide compelling support for a scenario of small-scale ecological divergence along multiple ecological niche dimensions, possibly driven by competitive interactions between species, and acting sequentially over time in a leapfrog pattern.
... General dynamic model of oceanic island biogeography (GDM) and ATT 2 (i.e., (2018) and references therein; Wijninga (1996). In the páramos of the Northern Andes, for example, the early species-poor páramo (the "proto-páramo"; Hooghiemstra, 1984;Van der Hammen & Cleef, 1986;Van der Hammen et al., 1973) was later enriched by the numerous immigrating genera from Neotropical and temperate zones (Cleef, 1979;Sklenář, Dušková, & Balslev, 2011;Wallace, 1880). Present-day páramo endemism, therefore, consists of a mix of taxa originating from páramo ancestors and more recent immigrants, both of which contributed to endemism through evolutionary radiations during the Pleistocene (Morrone, 2018;Nürk et al., 2020). ...
Aim
Mountains and islands are both well known for their high endemism. To explain this similarity, parallels have been drawn between the insularity of “true islands” (land surrounded by water) and the isolation of habitats within mountains (so‐called “mountain islands”). However, parallels rarely go much beyond the observation that mountaintops are isolated from one another, as are true islands. Here, we challenge the analogy between mountains and true islands by re‐evaluating the literature, focusing on isolation (the prime mechanism underlying species endemism by restricting gene flow) from a dynamic perspective over space and time.
Framework
We base our conceptualization of “isolation” on the arguments that no biological system is completely isolated; instead, isolation has multiple spatial and temporal dimensions relating to biological and environmental processes. We distinguish four key dimensions of isolation: (a) environmental difference from surroundings; (b) geographical distance to equivalent environment [points (a) and (b) are combined as “snapshot isolation”]; (c) continuity of isolation in space and time; and (d) total time over which isolation has been present [points (c) and (d) are combined as “isolation history”]. We evaluate the importance of each dimension in different types of mountains and true islands, demonstrating that substantial differences exist in the nature of isolation between and within each type. In particular, different types differ in their initial isolation and in the dynamic trajectories they follow, with distinct phases of varying isolation that interact with species traits over time to form present‐day patterns of endemism.
Conclusions
Our spatio‐temporal definition of isolation suggests that the analogy between true islands and mountain islands masks important variation of isolation over long time‐scales. Our understanding of endemism in isolated systems can be greatly enriched if the dynamic spatio‐temporal dimensions of isolation enter models as explanatory variables and if these models account for the trajectories of the history of a system.
... In these regions, grasslands were predominant under cooler and drier glacial weather conditions in both high and lowlands (Behling et al., 2004), while during the Pleistocene, savannahs expanded both north and south of the equator, covering large portions of the current grasslands (Behling and Hooghiemstra, 2001;Behling, 2002). Grassland flora is frequently found in periodically cold climates, since a lack of tolerance to the cold limits the presence of other, non-adapted taxa (Donoghue, 2008;Sklenár et al., 2011). Consequently, cooler climatic conditions foster the occurrence of many specialized plant species (Bredenkamp et al., 2002). ...
Phylogenetic niche conservatism can be investigated at multiple scales on an explicit geographical context. Haplotype-based comparative analyses of lineages occupying the same region, and thus subjected to similar environmental factors, allow decoupling shared evolutionary and ecological patterns, as well as multiple dimensions of adaptive diversification. Here we aimed to assess the role of environmental drivers on diversification of subtropical grassland, based on haplotypic diversity of two plant genera. We sampled two closely related and co-distributed grassland plant genera, Petunia and Calibrachoa, across their entire distribution area. Eigenvectors extracted from pairwise distances based on chloroplast DNA haplotypes were used to fit Phylogenetic Signal-Representation (PSR) curves to estimate evolutionary patterns in 19 bioclimatic variables and altitude. The PSR curves showed that altitude, precipitation, and temperature variables changed at different rates with haplotype differentiation. Altitude and temperature traits evolved under conditions closer to a neutral dynamics, whereas precipitation traits differentiated following more complex models. Our results indicated that the diversification in the two genera was more limited by precipitation conditions. Based on these novel findings, we suggest that future studies should test the possible impact of precipitation variables on the process of ecological differentiation in these genera.
... These estimates are contemporary with the environment they live in, since the Andes reached its current elevation during the Pleistocene [1]. The increase in elevation created suitable conditions for the development of high elevation species [59], which are thought to have evolved from closely related lineages from the lowland tropical areas, as well as from lineages from temperate regions [9,60,61]. Studies of plant lineages from páramo also show accelerated rates of diversification during this period of time [9]. ...
The ant-loving beetle genus Panabachia Park 1942 is a poorly studied beetle lineage from the new world tropics. We recently collected Panabachia from several previously unrecorded locations in the páramo biome of the high Ecuadorian Andes, with males exhibiting great morphological variation in the distribution of the foveae and depressions in the pronotum, as well as aspects of the male genitalia. Here, we employ phylogenetic and species delimitation methods with mitochondrial (COI) and nuclear protein-coding (wingless) gene sequences to examine the concordance of morphological characters and geography with hypothesized species boundaries. Three methods of species delimitation (bPTP, GMYC and Stacey) were used to estimate the number of species, and divergence times between putative species using molecular clock calibration. Phylogenetic analysis revealed two parallel radiations, and species delimitation analyses suggest there are between 17 and 22 putative species. Based on clade support and concordance across species delimitation methods we hypothesize 17 distinct clusters, with allopatric speciation consistent with most geographic patterns. Additionally, a widespread species appears to be present in northern páramo sites, and some sister species sympatry may indicate other diversification processes have operated on certain lineages of Panabachia. Divergence time estimates suggest that Panabachia originated in the Miocene, but most species analyzed diverged during the Pliocene and Pleistocene (5.3-0.11 Mya), contemporaneous with the evolution of páramo plant species.
... In this region, the Andean Cordillera strongly influenced evolutionary processes in both highland and lowland flora (Antonelli et al., 2009). Although the highland plateaus in southern Brazil are lower than the highest altitudes in the Andean Cordillera, an Andean origin is attributed to several plant groups inhabiting the Brazilian highland grasslands (Safford, 1999;Sklenář et al., https://doi.org/10.1016/j.ympev.2019.106614 Received 10 July 2019; Received in revised form 9 September 2019; Accepted 9 September 2019 2011; Iganci et al., 2013); moreover, some of the Andean biomes and the niches from the SHG have similar temperature and humidity conditions (Safford, 1999). ...
Calibrachoa is a charismatic South American genus of Solanaceae, closely related to Petunia, which encompasses approximately 30 species. Studies that were based solely on plastid molecular markers indicated the monophyly of the genus and distributed its species in two subgenera; to date no phylogeny has included a broad morphological variants and nuclear markers. Here, we present a phylogenetic analysis based on eight plastid and eight nuclear markers that cover the most extensive geographic distribution for the genus. We use this phylogeny to infer the biogeographic history of the genus and to understand the primary drivers for species diversification. Our results yield a fully supported tree where monophyly is confirmed to genus and subgenera. The species of Stimomphis subgenus that were previously considered uncertain, here emerge in four highly supported clades. The hypothesis of niche conservatism is confirmed, and adaptive radiation explains the species diversification. The lowlands are the most likely ancestral area of the genus, subgenera, and two clades of Stimomphis subgenus. Our results constitute an excellent starting point for further evolutionary and taxonomic studies and explain several uncertain evolutionary relationships in the group and the evolution of their distribution.
Decades of empirical research have revealed how the geological history of our planet shaped plant evolution by establishing well‐known patterns (e.g., how mountain uplift resulted in high rates of diversification and replicate radiations in montane plant taxa). This follows a traditional approach where botanical data are interpreted in light of geological events. In this synthesis, I instead describe how by integrating natural history, phylogenetics, and population genetics, botanical research can be applied alongside geology and paleontology to inform our understanding of past geological and climatic processes. This conceptual shift aligns with the goals of the emerging field of geogenomics. In the neotropics, plant geogenomics is a powerful tool for the reciprocal exploration of two long standing questions in biology and geology: how the dynamic landscape of the region came to be and how it shaped the evolution of the richest flora. Current challenges that are specific to analytical approaches for plant geogenomics are discussed. I describe the scale at which various geological questions can be addressed from biological data and what makes some groups of plants excellent model systems for geogenomics research. Although plant geogenomics is discussed with reference to the neotropics, the recommendations given here for approaches to plant geogenomics can and should be expanded to exploring long‐standing questions on how the earth evolved with the use of plant DNA.
Past studies in plant phylogenetics have shed light on how the geological history of our planet shaped plant evolution by establishing well-known patterns (e.g., how mountain uplift resulted in high rates of diversification and replicate radiations in montane plant taxa). Under this approach, information is transferred from geology to botany, by interpreting data in light of geological processes. In this synthesis, I propose a conceptual shift in this traditional approach to specifically transfer information from botany to geology. This conceptual shift follows the goals of the emerging field of geogenomics and emphasizes that plant phylogenetics can go beyond investigating patterns in light of landscape change, to reduce the inherent uncertainty in models of paleotopography, river system structure, and land connections through time. Current challenges that are specific to analytical approaches for plant geogenomics are discussed. I describe the scale at which various geological questions can be addressed from biological data, and what makes some groups of plants excellent model systems for geogenomics research. This synthesis highlights the critical role of classical botanical knowledge in identifying good study systems to unveil long-standing questions on how the earth evolved with the use of plant DNA.
The regions around the polar caps and elevation high enough to produce very cold, sometimes snow and ice-rich conditions, are the coldest corners on our planet. They support relatively species-poor vegetation adapted to seasonal alternation of cold and less cold periods or diurnal alternation of cold nights and hot days. The biomes occurring under such conditions are called tundra (tree-less, moss- and lichen-rich dwarf shrublands and sedgelands) when found beyond the climatic tree line separating vegetation zones. In the case of high mountains, similar biomes occur above the timberline (tree line), separating the alpine belt from the rest of the vegetation on a mountain range. Walter’s zonobiome system recognised only one zonobiome, encompassing all these cold regions—the zonobiome IX (Tundra). The Global Hierarchical Biome System (GHBS) separates the Arctic (A1) and Antarctic (A4) zonobiomes (by splitting Walter’s zonobiome IX) and assigns the respective alpine temperate biomes to the respective zonobiomes A1 and A4. The global biome position of the subtropical and tropical alpine biomes has been confusing. The GHBS presents a novel solution by recognising these biomes at the zonobiome level (the zonobiome A2, Subtropical Alpine Zone and the zonobiome A3, Tropical Alpine Zone), characterised by macroclimatic dynamics of the climatic systems affecting the Tropics and Subtropics. Abandoning the orobiome concept of Walter’s system assisted in developing the new scheme of classification of the alpine biome. The tree line is the crucial climatic and ecological threshold separating the world of the alpine biomes from the rest of the planet’s vegetation. Its position is under the control of many climatic and disturbance factors, modified by the mass-elevation effect (MEE) in many instances. This chapter revisits the MEE phenomenon and suggests new interpretations and ideas to understand the physical nature of the MEE, the influence of exposure and wind shadowing by surrounding mountains on the MEE, the effect of the cloud-belt formation and its relation to the soil nutrient status, nutrient cycling, and carbon residence, and finally the effect of the distance from the sea on the MEE.KeywordsAlpine biomesAntarcticaArctic biomeDiurnal temperature dynamicsOromediterranean biomeTundraMass elevation effectOro-complexOrobiomePáramoPolar desertPunaTree lineVegetation belt
Aim
The Andean paramo is the most biodiverse high-mountain region on Earth and past glaciation dynamics during the Quaternary are greatly responsible for its plant diversification. Here, we aim at identifying potential climatic refugia since the Last Glacial Maximum (LGM) in the paramo, according to plant family, biogeographic origin, and life-form.
Location
The paramo region in the Northern Andes
Methods
We built species distribution models for 664 plant species to generate range maps under current and LGM conditions, using five General Circulation Models (GCMs). For each species and GCM, we identified potential (suitable) and potential active (likely still occupied) refugia where both current and LGM range maps overlap. We stacked and averaged the resulting refugia maps across species and GCMs to generate consensus maps for all species, plant families, biogeographic origins and life-forms. All maps were corrected for potential confounding effect due to species richness.
Results
We found refugia to be chiefly located in the southern and central paramos of Ecuador and Peru, especially towards the paramo ecotone with lower-elevation forests. However, we found additional specific patterns according to plant family, biogeographic origin and life-form. For instance, endemics showed refugia concentrated in the northern paramos.
Main conclusions
Our findings suggest that large and connected paramo areas, but also the transitional Amotape-Huancabamba zone with the Central Andes, are primordial areas for plant species refugia since the LGM. This study therefore enriches our understanding on paramo evolution and calls for future research on plant responses to future climate change.
Complex geological events such as mountain uplift affect how, when, and where species originate and go extinct, but measuring those effects is a longstanding challenge. The Andes arose through a series of complex geological processes over the past c. 100 million years, impacting the evolution of regional biota by creating barriers to gene flow, opening up new habitats, and changing local climate patterns. Bomarea are tropical geophytes with ranges extending from central Mexico to central Chile. Of the roughly 120 species of Bomarea, most are found in the Andes, and previous work has suggested that Bomarea diversified rapidly and recently, corresponding with the uplift of the Andes. While many Bomarea species occur over small, isolated ranges, Bomarea edulis occurs significantly beyond the ranges of any other Bomarea species (from central Mexico to northern Argentina) and is thought to have potentially human-mediated dispersal, due to its status as a pre-Columbian food plant. To untangle the potential drivers of diversification and biogeographic history in Bomarea, we used a target-capture approach to sequence nuclear loci of 174 accessions of 124 species, including 16 outgroup species from across the family (Alstroemeriaceae). We included 43 individuals of B. edulis from across its range to assess species monophyly and identify infraspecific phylogeographic patterns. We model biogeographic range evolution in Bomarea and test if Andean orogeny has impacted its diversification. We find that Bomarea originated in the central Andes during the mid-Miocene, then spread north, following the trajectory of major mountain uplift events. Most observed speciation events occurred during the Pleistocene, while global climate cooled and oscillated and the northern Andes achieved their current form. Furthermore, we find that Andean lineages diversified faster than their non-Andean relatives. These results demonstrate a clear macroevolutionary signal of Andean orogeny on this neotropical radiation.
Simple Summary: Two species of Andean-endemic fireflies are herein revised, and their evolutionary relationships addressed for the first time. We show that despite their similarities, these two species are distantly related. We provide original reports of these species interacting with Andean-en-demic flowers for the first time, and we propose that their similarities are due to participation in mimicry rings. Abstract: South America is likely the cradle of several New World firefly lineages but remains largely understudied. Despite several advances in firefly systematics in the Neotropical region, the Andean region has been largely unstudied for over a century. The Colombian Páramos are a critically threatened biodiversity hotspot that houses several endemic species, including the firefly ge-nus Pseudolychnuris, with two species-P. vittata and P. suturalis. Here, by analyzing the phyloge-netic relationships of Pseudolychnuris, we found that this genus is polyphyletic. Pseudolychnuris vit-tata and P. suturalis were found to be distantly related despite the striking similarity in outline and color pattern of males and females. We redescribe Pseudolychnuris and its type species P. vittata. Moreover, we revalidate Alychnus Kirsch, 1865 stat. rev. to accommodate A. suturalis comb. nov., also redescribed here. We provide updated distribution maps and report field observations for both monotypic genera. Since adults visit flowers and interact with pollen and nectar, Pseudolychnuris and Alychnus may be occasional pollinators of Andean-endemic plants, a phenomenon previously neglected. Our findings reveal an interesting case of convergence between Pseudolychnuris and Alychnus-probably associated with life in the Páramos-and shed light on character evolution in the Photinini lineage of fireflies.
La compréhension des mécanismes évolutifs et écologiques à l’origine des patrons globaux de Biodiversité est une question centrale dans les domaines de l’Écologie et de l’Évolution. Les phylogénies, représentations des liens évolutifs entre les lignées du monde vivant, constituent le socle incontournable permettant d’identifier les processus à l’origine de ces patrons. Cette thèse présente les travaux de recherche que j’ai entrepris sur l’évolution de la diversité de papillons de la famille des Saturniidae Boisduval 1837 (Lepidoptera : Bombycoidea). Cette famille, particulièrement diversifiée biologiquement et morphologiquement, comprend près de 3500 espèces distribuées sur l’ensemble des continents. A l’aide d’approches phylogénomiques, j’ai inféré les relations phylogénétiques entre tous les genres décrits – à partir desquelles j’introduis une nouvelle classification des Saturniidae - et j’ai proposé une phylogénie incluant toutes les espèces du genre Néotropical Copaxa. J’ai également conçu un pipeline phylogénomique permettant la génération de mégaphylogénies – phylogénies datées de plus de mille feuilles dont la complétion est >50% des espèces – que j’ai appliqué sur un jeu de données combinant des éléments ultraconservés du génome et des codes-barres ADN pour générer une phylogénie représentant entre 88 et 100% des espèces connues des Saturniidae. Les phylogénies ainsi inférées ont ensuite été utiliser afin d’examiner les dynamiques spatio-temporelles de la diversification des Saturniidae. Dans leur ensemble, les résultats obtenus au cours de ma thèse démontrent l’importance des facteurs biotiques dans la diversification spatiale et temporelle de la famille. J’ai notamment identifié que la capacité de tisser des cocons pleins et denses ainsi qu’un fort degré de polyphagie ont été les clés du succès biogéographique des Saturniidae et que l’hétérogénéité des taux de diversification au sein de la famille s’explique par l’évolution de traits en lien avec la stratégie dite de « capital breeding » de ces papillons : augmentation de la taille et de la polyphagie. J’ai également inféré que la niche climatique des Copaxa, héritée d’un ancêtre distribué dans la région Holarctique, avait façonné leur patron de diversification au sein de la région Néotropicale : la majorité des espèces volent dans les zones montagneuses, aux climats proches de ceux des zones tempérées, et les deux colonisations indépendantes de la chaine andine ont impliqué des shifts positifs des taux de diversification (évènements de dispersification). Dans leur ensemble, ces résultats représentent une avancée majeure dans la compréhension de la phylogénie et de l’évolution des Saturniidae, des Lépidoptères et plus généralement constituent un ensemble de supports permettant de mieux comprendre les processus évolutifs qui ont généré l’incroyable diversité des insectes.
Several studies have demonstrated the contribution of northern immigrants to the flora of the tropical Andes – the world’s “hottest” biodiversity hotspot. However, much less is known about the biogeographic history and diversification of Andean groups with southern origins, although it has been suggested that northern and southern groups have contributed roughly equally to the high Andean (i.e. páramo) flora. Here we infer the evolutionary history of the southern hemisphere plant genus Gunnera , a lineage with a rich fossil history and an important ecological role as an early colonising species characteristic of wet, montane environments . Our results show striking contrasts in species diversification, where some species may have persisted for some 90 million years, whereas others date to less than 2 Ma since origination. The outstanding longevity of the group is likely linked to a high degree of niche conservatism across its highly disjunct range, whereby Gunnera tracks damp and boggy soils in cool habitats. Colonisation of the northern Andes is related to Quaternary climate change, with subsequent rapid diversification appearing to be driven by their ability to take advantage of environmental opportunities. This study demonstrates the composite origin of a mega-diverse biota.
Several studies have demonstrated the contribution of northern immigrants to the flora of the tropical Andes – the world’s “hottest” biodiversity hotspot. However, much less is known about the biogeographic history and diversification of Andean groups with southern origins, although it has been suggested that northern and southern groups have contributed roughly equally to the high Andean (i.e. páramo) flora. Here we infer the evolutionary history of the southern hemisphere plant genus Gunnera , a lineage with a rich fossil history and an important ecological role as an early colonising species characteristic of wet, montane environments . Our results show striking contrasts in species diversification, where some species may have persisted for some 90 million years, whereas others date to less than 2 Ma since origination. The outstanding longevity of the group is likely linked to a high degree of niche conservatism across its highly disjunct range, whereby Gunnera tracks damp and boggy soils in cool habitats. Colonisation of the northern Andes is related to Quaternary climate change, with subsequent rapid diversification appearing to be driven by their ability to take advantage of environmental opportunities. This study demonstrates the composite origin of a mega-diverse biota.
The paramo is a unique and severely threatened ecosystem scattered in the high northern
Andes of South America. However, several further, extra-Andean paramos exist, of which a particular case is situated on the active volcano Sumaco, in the northwestern Amazon Basin of Ecuador. We have set an elevational gradient of 600 m (3200–3800 m a.s.l.) and sampled a total of 21 vegetation plots, using the phytosociological method. All vascular plants encountered were typified by their taxonomy, life form and phytogeographic origin. In order to determine if plots may be ensembled into vegetation units and understand what the main environmental factors shaping this pattern are, a non-metric multidimensional scaling (NMDS) analysis was performed. In addition, species turnover was quantified in order to appreciate the quantity and sort of species which are responsible for the similarity or dissimilarity between vegetation units. Therefore, a SIMPER similarity percentage analysis was conducted. We encountered 68 plant species belonging to 54 genera and 31 families, of which three are Ecuadorian endemics. The most frequent life forms were erect herbs, rosette and tussocks, whereas the least were cushions. At genus level, 44% of the Sumaco paramo flora was of tropical origin, followed by temperate (33%) and finally cosmopolitan (22%). The neotropical montane element was the most represented with 15 species, followed by the Austral-Antarctic with ten, wide temperate with another ten and cosmopolitan with seven. Regarding vegetation, four floristically distinct groups were segregated being lower gradient (3250–3500 m a.s.l.) and high altitude (3500–3800 m a.s.l.)
Neotropical montane Compositae range from ephemerals to 20 m tall trees and are found in nearly all habitats from forests to paramo and puna. There are a total of 303 genera and 3424 species. In the Andes, the tribal distributions of the Compositae fall into one of the following four groups: 1) tribes that have important centers of distribution in the Andes and are found wholly or primarily in the Western Hemisphere, including the Heliantheae, Eupatorieae, Mutisieae, Liabeae, and Barnadesieae; 2) tribes that are well represented in the Andes and have specialized elements there but are common in both the Eastern and Western hemispheres, including the Senecioneae, Astereae, and Vernonieae; 3) tribes represented by a few species but whose distribution is primarily nearctic or in the Eastern Hemisphere or both, including the Gnaphalieae, Plucheeae, and Lactuceae; and 4) the remaining tribes. Some tribes and genera in the first two groups originated in the Andes and dispersed elsewhere, whereas other taxa originated elsewhere in the Western Hemisphere and radiated extensively into the Andes. -from Authors
A revision of the genus Chuquiraga (Compositae-Mutisieae). The genus Chuqui- raga as here treated comprises 19 species of xerophyllous bushes of South America; the history and systematic relationships within the genus and with other genera,and the morphology, geographical distribution and economic importance of the species are discussed. The taxonon)ic treatment includes a description of the genus, keys to the sections, series and species, and a list of excluded names. All the taxa are described and illustrated and distribution maps are given. In many cases, nomenclatural problems, intraspecific variability and affinities between the species are also analyzed.In this revision a new infrageneric classification is proposed, the genus being divided into two sections: Acanthophylla nov. sect., and Sect. Chuquiraga with two series-Parviflorae nov. ser. and Ser. Chuquiraga. Other taxonomical novelties are:Two new subspecies are describéd {Ch. spinosa Less, subsp. australis and subsp. huamanpinta) and three changes of status are proposed {Ch. spinosa subsp. rotundifolia (Weddell) nov. stat., Ch. ulicina subsp. acicularis (Don) nov. stat. and Ch. erinacea subsp. hystrix (Don) nov. stat.). The name Ch. parviflora (Gris.) Hieron., which had been reduced to synonymy of Ch. opppsi- tifolia Don, is rehabilitated, and the morphological and geographical differences between both species are discussed. A new epithet is proposed {Ch. morenonis (O. Ktze) nov. stat.) for Ch. argentea (Speg.) Speg., name invalidated by an earlier homonym. The name Ch. spinosa (Ruiz et Pav.) Don, erroneously used to designate the taxon here described as Ch. spinosa Less, subsp. huamanpinta, is excluded form the genus. The following names are reduced to synonymy for the first time: Ch. erinacea f. pulvinata Cabrera; Ch. incana Phil.; Ch. insignis var. armata Weddell; Ch. johnstonii Tovar; var. lancifolia (H. et B.) Koster; Ch. kingii Ball; Ch. oppositifolia var. macrantha Gay; Ch. oppositi- folia valr. macrocephala Weddell; Ch. pseudoruscifolia Muschler; Ch. revoluta Field et Gardn; Ch. ulicina var. incana (Phil.) Johnston.
Aragoa is a genus endemic to the páramos of Colombia and Venezuela. The systematic position of the genus has been controversial because of its peculiar morphological features, although many authors have placed it in Scrophulariaceae. Because of this and the fact that the delimitation of Scrophulariaceae and allied families has recently changed, a molecular analysis is used here to investigate the phylogenetic position of the genus. Both rbcL and ITS sequences show that Aragoa is sister to Plantago, in a clade including also Veronica, Hemiphragma and Digitalis. These results put in doubt previous hypotheses about the biogeography of this páramo genus and indicate that more phylogenetic analyses are necessary to study the history of the páramo biota.
Two new species from the family Asteraceae, tribe Astereae, were collected during botanical investigations in the Ecuadorian Andes. Oritrophium llanganatense Sklenář & H. Robinson and Floscaldasia azorelloides Sklenář & H. Robinson are here described and illustrated. Oritrophium llanganatense is distinct from other species of the genus by a combination of abaxially lanate leaves with outer phyllaries narrowly ovate to oblong. Floscaldasia azorelloides differs from the other species of the genus by its three-lobed leaves. The two species inhabit the upper superpáramo and are restricted to remote areas of the Ecuadorian Eastern Cordillera. /// Dos nuevas especies de la familia Asteraceae, tribu Astereae, se colectaron durante investigaciones botánicas en el superpáramo del Ecuador. Las dos especies, Oritrophium llanganatense Sklenář & H. Robinson y Floscaldasia azorelloides Sklenář & H. Robinson, se describen e ilustran. Oritrophium llanganatense difiere de las otras especies del género por tener hojas lanosas abaxiadamente y brácteas exteriores ovadas a oblongas. Floscaldasia azorelloides difiere de las otras especies del género por tener las hojas trilobadas. Las especies se encuentran en el superpáramo alto en áreas remotas de la Cordillera Oriental del Ecuador.
A preliminary synthesis of diversification patterns of alpine plants in the Mediterranean region of Europe is presented based on seven plant groups displaying morphological differentiation and infraspecific taxa. Both previous and new phylogenetic results from ITS sequences and fingerprinting data suggest different colonization routes and modes of speciation in Androsace vitaliana (recent differentiation in the Iberian Peninsula), Anthyllis montana (west-to-east colonization and differentiation in Europe), Arenaria tetraquetra (colonization and differentiation from SE Iberian mountains to the Pyrenees; increasing number of chromosome complements), Saxifraga oppositifolia (colonization from the arctic to the Iberian Peninsula), Saxifraga pentadactylis (differentiation in Mediterranean and Eurosiberian mountains by geographic isolation), and Soldanella alpina (differentiation and colonization from northern Iberia to the Alps, and then to the Pyrenees and the Balkan Peninsula). Relative static diversification of Juniperus communis var. saxatilis in Europe, based on identity of chloroplast trnL-F sequences, is also described. Most morphological variation, expressed by number of subspecies recognized in previous taxonomic treatments of the seven plant groups, appears to have occurred during the Pleistocene (< 1.75 Myr). Recurrent change of Quaternary climatic conditions in the Mediterranean Basin, coupled with geographic characteristics, life cycle, dispersal mechanisms, and pre-Holocene genetic structure are not convincing factors to account for all the observed diversification. Additionally, stochastic processes are also considered for evaluating present-day distributions and processes of speciation.
El género Aragoa (Scrophulariaceae), endémico del páramo y subpáramo de Colombia y Venezuela, contaba con escasas colecciones hasta mediados de este siglo y carecía de una revisión reciente. Como resultado del estudio de las nuevas colecciones se observó una notable falta de trabajo descriptivo, que se tradujo al final de la presente revisión en la descripción de 14 nuevos táxones y otros nuevos aportes que a continuación se relacionan.
En la filotaxis de las plántulas de Aragoa se detectó un cambio de patrón de foliación, inicialmente opuesto-decusado, que por pérdida de sincronía se transforma en esparcido, y un aumento rápido del número de ortósticos helicoidalmente ascendentes en los ejes jóvenes. Se detectaron fenómenos de prolificación de ejes florales, que dan como resultado la aparición de ramas cortas, alternas, en la axila de brácteas estériles. Se establecieron cinco tipos básicos de sección transversal en la hoja, carácter de gran relevancia en la diagnosis de las especies. Se consideraron seis tipos de corolas, en función de la longitud y forma del tubo, así como de la de la distribución del indumento. El número de semillas, su tamaño y la anchura de su ala también suministraron información taxonómicamente relevante. Se efectuaron estudios concretos en morfología de semillas, palinología y cariología, que suministraron interesante información sobre el género; así, los caracteres polínicos, señalados como importantes para la separación del género en una tribu autónoma, revelaron diferencias discretas a nivel de especie. Se hizo el primer recuento cromosómico en una especie de este género (A. abietina) y se obtuvo un número somático de 2n = c. 52.
En relación con la polinización, se detectó proterandria en el género y se delimitaron tres tipos de corolas, que son visitadas preferentemente por dípteros y ápidos. En lo referente a hibridación, especiación y tendencias evolutivas, se plantea una hipótesis de introgresión y de especiación hibridógena reticulada en la historia y diversificación del género, tomando como base las estimaciones sobre la distribución espacial de los híbridos en el medio, valores de fertilidad polínica y la presencia de caracteres morfológicos cruzados o desviantes en cada grupo. Se esbozaron las posibles tendencias evolutivas basándose en argumentos morfológicos y biogeográficos; dentro de la sección Aragoa, son considerados los grupos abietina y lycopodioides como los más primitivos.
Se hizo un seguimiento histórico de la ubicación taxonómica de este género atípico y se aportan nuevos datos sobre la relación de Aragoa con otros géneros y tribus de la familia Scrophulariaceae, en especial con los de afinidad ausrral-antártica de la tribu Veroniceae.
En cuanto al tratamiento taxonómico, y como resultado del estudio morfológico llevado a cabo, se subdivide Aragoa en dos subgéneros, uno de ellos con dos secciones, para lo cual se describen A. subgén. Luteoaragoa y A. sect. Ciliatae. Se delimitan dentro de la sección Aragoa tres grupos de especies que se relacionan por grupos de caracteres y que podrían representar tres líneas evolutivas independientes. Fueron descritas 11 especies, tres subespecies y cuatro híbridos. Se presentan claves para los subgéneros, secciones, especies y subespecies y los mapas de distribución de las diferentes especies. Se hace una clasificación de los sistemas de páramos de Colombia y Venezuela, que comprende cuatro unidades básicas y varias subunidades, de acuerdo con los patrones de distribución observados en Aragoa y en algunos otros géneros de los páramos. Se considera que Aragoa tiene un centro principal de diversidad y dos centros secundarios (dos de ellos en la Cordillera Oriental colombiana); se indican además las posibles vías de radiación y diversificación en el norte de los Andes.
Páramo vegetation was quantitatively surveyed in 192 samples on altitudinal gradients in twelve sites in Ecuador. Thirty-one communities were identified, comprising 348 vascular plant taxa (voucher specimens deposited at Kew and QCA, Quito). These communities could be assigned to eight general types of páramo vegetation located between the upper forest limit and the snow-line: Shrubby Sub-páramo, High Altitude Dwarfshrub Páramo, Tussock Páramo, Bamboo Páramo, Espeletia Páramo, Cushion Páramo, Rainshadow Desert Páramo and High Altitude Desert Páramo. Community types were more closely related to altitude than to other variables such as burning, trampling, grazing and pH.
The species were assigned to ten defined growth form categories. The distributions of these categories in 192 páramo vegetation samples were described. Twelve growth form communities were identified. Field temperature measurements of plant parts demonstrated that some plants maintained day and night temperatures several degrees Celsius above ambient levels.
The effect of fire on cyclical and successional processes within páramo vegetation were described. Two experimental páramo fires reached temperatures in excess of 400°C in the upper tussock canopy, while the tussock bases were mostly below 65°C. In a quantitative study, the majority of plant-by-plant replacements soon after a páramo fire did not depart from those expected by chance, though some trends were observed
and described.
Field trials in Central Ecuador provided net aboveground grassland community productivity estimates for five sites. Estimates ranged from 1,359 g m-2 y-1 at 3,100 m to 512 g m-2 y-1 at 3,950 m.
In greenhouse experiments, tussock grasses from Calamagrosth spp. at three altitudes in the páramo were grown in a diallel design under two watering regimes. In both regimes, the grass from the lower altitude yielded more and had a higher relative yield than that from the higher altitude. RYTs in the wettest treatment lay between 1.2 and 2.5, those of the drier treatments were not greater than 1.0.
In the Neotropics, the Ericaceae are an Andean-centered family, adapted to moist, open, cool montane environments. Overall species richness increases nearer the Equator, with the highest species numbers concentrated in Colombia and Ecuador between 1000 m and 3000 m. There are 46 genera (70% endemic) and about 800 species (ca. 94% endemic) of Ericaceae native to the Neotropics. Five biogeographical regions are recognized for the neotropical Ericaceae, with the greatest species diversity found in the Andes of northwestern South America. Following Pliocene/Pleistocene mountain-building and climatic events, neotropical Ericaceae underwent dynamic speciation and extensive adaptive radiation due to their ecological and life-form plasticity, colonization abilities, adaptation to epiphytic habits, and coevolution with hummingbirds. Given high diversity and singularity within neotropical Ericaceae, along with high levels of habitat alteration, protection of Andean montane ecosystems should become a priority for the conservation of Ericaceae in the Neotropics.
Some scientists have suggested that the Huancabamba Depression in northern Peru—i.e., the partial interruption of the Andean chain by the Rio Chamaya drainage system—represents a major biogeographical barrier to montane taxa. Others have suggested that the Amotape-Huancabamba Zone in the Andes of northern Peru and the extreme south of Ecuador is an area of particular biological diversity and possibly a phytogeographical zone in its own right.
The phytogeography of this area is investigated here with data mainly from the Loasaceae, supplemented by data on other plant and animal groups and by some new data fromPassiflora L. (Passifloraceae) andRibes L. (Grossulariaceae). The Huancabamba Depression itself does not seem to have been a major dispersal barrier for these groups. However, a phytogeographical zone—the Amotape-Huancabamba Zone—between the Río Jubones system in Ecuador and the Río Chamaya system in Peru can be recognized from the available data. This zone seems to be home to numerous endemic species and species groups and has a high level of diversity (6–8 times as high as adjacent areas to the north and to the south in the groups studied). The species of this area show narrow endemicity and often strikingly aberrant morphological characters, compared with representatives of the same groups from other areas.
The overlap between northern and southern groups in the area, the mosaic nature of its habitats (geology, geography, and climate), and a varied geological history (habitat fragmentation, secondary contact) seem to be the three most important factors contributing to these patterns of diversification. At least some phylogenetically old taxa appear to have survived in the Amotape-Huancabamba Zone. The region thus seems to be home to a high number of both neoendemics and paleoendemics.
In both the afroalpine flora, inhabiting the highest vegetation belt of the high East African mountains, and the paramo flora in South America, the dominant plants belong to five life forms (giant rosette plants, tussock grasses, acaulescent rosette plants, cushion plants, and sclerophyllous shrubs), which have evolved through progressive adaptation to the tropical-alpine climate with "summer every day and winter every night'. In both areas there has been differentiation into vicarious taxa under the influence of geographical isolation. There are, however, important differences in the extent of diversification, because the afroalpine flora consists of distinctly isolated enclaves, widely separated from other mountains both northwards and southwards, whereas the paramo flora has a more continuous distribution along the Andean ranges. -from Author
Some 150 indigenous vascular plant genera were recognized in the paramo of the Cordillera de Talamanca, Costa Rica. Seven geographic flora elements were distinguished: paramo (with 4% of the genera), neotropical-montane (25%), wide tropical (7%), holarctic (15%), austral-antarctic (14%), wide temperate (24%), and cosmopolitan (11%). This subdivision was compared with those of the Colombian paramos. The larger proportion of the temperate component in Costa Rica may be attributed to a more northern geographical position of the country. Otherwise, the Talamanca paramo flora shares c95% of its vascular genera with the Andes. -from Authors
Approximately 185 species of Lycopodiaceae are known to occur in the Neotropics: ca. 150 belong in the genus Huperzia, ca. 8 in Lycopodium, and ca. 25 in Lycopodiella. The species are enumerated according to assumed relationship, with information of the most important synonyms, a summary of their distribution, comments on their morphology and variability, and reference to selected illustrations. Species delimitation is problematic throughout the family. This is due to the simple morphology and the plasticity of the characters. Morphogenesis seems unstable in many species and may be strongly affected by environmental factors. Most characters are variable within a species, e.g., stem thickness, number of leaf orthostichies, leaf crowding, leaf direction, development of teeth on leaf margins, color, degree of heterophyllous differentiation. Often the diagnostic features of closely related species are without apparent adaptive significance. Hybridization is believed to occur rather freely, but the putative hybrids often have normally developed spores. Three new combinations, Huperzia tubulosa (Maxon) B. Oslashllg., Huperzia watsoniana (Maxon) B. Oslashllg., and Lycopodiella torta (L. Underw. & F. Lloyd) B. Oslashllg., are proposed.
Morphological and distributional data are presented for Hedyotis serpyllacea, native to Guatemala and southern Mexico. The species is transferred to Arcytophyllum, extending the range of the genus northward from Costa Rica, Panama, and South America.
Palynological studies in the Northern Andes have shown a gradual upheaval of the Cordillera during the Late Pliocene and the creation of the high montane environment. A long sequence of glacial and interglacial periods has been recorded from the Pleistocene. The successive appearance of new taxa, by evolutionary adaptation from the local neotropical flora and from elements immigrated from the holarctic and austral-antartic floral regions, can be followed step by step. For the Last Glacial to Holocene sequence the contemporaneity of the changes of temperature with those recorded from the northern temperate latitudes could be proved by 14 C dating During the coldest part of the Last Glacial the tree line descended to c. 2000 m altitude, i.e. 1200-1500 m lower than where it lies today. During the period from c. 21,000 to c. 13,000 B.P. the climate was, moreover much drier. Even taking the greater aridity into account, the lowering of the temperature during the coldest part of the Last Glacial may have been 6-7⚬ C or more. The lowering of the temperature in the tropical lowlands during glacial times may have been c. 3⚬ C. The temperature gradient must, therefore, have been steeper than it is today. In the coastal lowlands of Guyana and Surinam glacial-interglacial eustatic movements of sea level have been recorded. Pollen diagrams show in this area a considerable extension of savannas during glacial periods with low sea levels. In the inland savannas of the Llanos Orientales of Colombia and the Rupununi savanna of Guyana, several periods of grass-savanna and of savanna-woodland alternate during the Late Pleistocene and the Holocene; lower and higher lake levels corroborate the conclusions that these are caused by changes in the effective precipitation. One of the driest periods in the Rupununi seems to correspond to the time immediately before c. 13,000 B.P. Pollen data a series of samples from Rondonia, in the southern part of the Amazon basin, have shown that in that area grass-savannas replaced the tropical forest during a certain interval of Pleistocene age. From the above it appears that in considerable parts of the South American tropics a much drier climate prevailed during certain parts of the Pleistocene. A major dry period seems to have occurred during the later part of the Last Glacial, when the glaciers in the northern latitudes and in the Andes were reaching their maximum extension. These changes of climate and vegetation are of considerable importance for the explanation of speciation patterns and the recent distribution of plant and animal taxa.
Questa è la seconda parte della flora sinottica Prima Flora Colombiana. Essa segue il medesimo modello della prima parte (Burseraceae in Webbia 12: 375–441, 1957) ma per le Malpighiaceae le chiavi delle specie sono di tipo dicotonico. Corne nelle Burseraceae vengono dati i sinonimi, la distribuzione basata sulle raccolte, osservazioni tassonomiche, nomi vernacolari ed usi; vengono anche aggiunte considerazioni circa le proprietà narcotiche di alcune specie di Malpighiaceae (per esempio yagé, caapi).
This paper presents a perspective of how phylogenetic and phylogeographic hypotheses, based on nuclear DNA sequence variation (ITS) or amplified fragment length polymorphisms (AFLPs), can provide insights into the origin and evolution of the European high mountain flora. We focus on a diversity of unrelated herbaceous plant taxa that are broadly co-distributed across the European Alpine System, representing different taxonomic levels, and having either Mediterranean or Asian affinities (i.e., Anthyllis montana, Pritzelago alpina, Globularia vs. Soldanella, and Primula sect. Auricula). Our observations highlight that all taxa investigated began to diversify at the beginning of the Pleistocene or well within this period. Some of those taxa apparently followed different routes and modes of immigration, thereby colonizing the European high mountains only once (either from the East or the West) or repeatedly (from the Mediterranean Basin). Our observations further suggest that several high mountain taxa originated from lowland forms. While supporting earlier views, such a trend has generally been associated with pre-Quaternary rather than Pleistocene events. While several concordant patterns of (large-scale) spatial genetic differentiation are identified across taxa, such similarities may have arisen at either clearly different or roughly similar times. Finally, most speciation events likely occurred in allopatry, though more comprehensive studies are required to evaluate the relative importance of non-allopatric modes of speciation in the study area. We conclude that one major challenge to future evolutionary studies in European mountain plants is the accurate and reliable reconstruction of the tempo and mode of speciation across Quaternary time scales.
The generic composition of 10 tropicalpine floras is reviewed. Most genera in each flora have distributions extending to at least one temperate zone, and between 1/3 and 1/2 grow in both temperate zones. A northern element is most important on African mountains, and a southern element on Malesian mountains. South American tropicalpine floras are the largest, and have the largest endemic element. All tropicalpine environments are probably geologically young (the Andes perhaps to the least extent), their floras mainly deriving, by immigration over long distances, from cool-adapted temperate zone floras. Intra-regional variations are largely explicable in terms of mountain locations, and definition of the floras being compared. -Authors
The alpine enclaves of the high East African mountains provide a number of geographically and ecologically isolated temperate islands, inhabited by an afroalpine flora which is poor in species and peculiarly adapted to the extreme diurnal climate. Phytogeographically this afroalpine flora is of complex derivation. Its high degree of endemism indicates that its enclaves have long been isolated from each other and from other temperate areas. The high mountams harboring it have evidently stood isolated from each other since their origin, and Pleistocene climatic changes cannot have enabled direct contacts between the different alpine enclaves. Intermountain migration has probably occurred by independent long-distance dispersal. The frequency of apparent adaptations to different vectors is given in table 1. Establishment of newly dispersed afroalpine plants has necessitated climatic preadaptation and may have been facilitated by the occurrence of open habitats with weak competition. The vicarious plant communities occurring on the mountains appear to have been synthesized on each mountain separately after independent long-distance dispersal of the constituent species. The distribution of afroalpine plant communities seems to depend mainly on edaphic differences, and below the foreground of the glaciers there are few signs of regular successions.
Background: The genus Draba (Brassicaceae) has an arctic-alpine and montane distribution, and contains 355 accepted
species that encompass a broad range of ploidy levels.
Aims: We aimed (1) to explore the relationship between ploidy level and species richness throughout the geographical
distribution of Draba, and (2) to estimate rates of speciation and polyploidisation in the genus.
Methods: Species and their ploidy levels, obtained from Floras, herbaria and checklists, were mapped and analysed with
ArcView 9.1. Speciation and polyploidisation rates were calculated.
Results: We found that: (1) areas of high species richness have a high number of polyploid species; (2) diploid and
polyploid distributions overlap; (3) aneuploids, and uneven and lower polyploid levels (≤ 6x) are strongly associated with
the North American Cordillera; (4) species with high ploidy levels (> 10x) occur mainly in the Circum-North Region; and
(5) Draba has high rates of speciation and polyploidisation compared to other herbaceous plants.
Conclusions: Draba is a young polyploid complex as indicated from the geographical overlap of diploids and polyploids.
The North American Cordillera Region is characterised by recent speciation and radiation events, while the Circum-North
Region is characterised by both high levels of species migration and high ploidy levels. Regions of high species richness
and polyploidy are those most affected by past glaciation (i.e. mountainous and arctic regions). High rates of speciation and
polyploidy support the hypothesis that speciation in the genus has accelerated, and it is hypothesised that frequent glaciation
cycles during the Pleistocene were a cause of this acceleration.
Anatomy of leaf, stem, and root of more than 100 species in subtribe Dendrobiinae (Orchidaceae) was studied with the light microscope to provide a comparative anatomical treatment of these organs, to serve as an independent source of evidence that might be taxonomically important, and to recommend such reinterpretations of existing classifications as are suggested by a phylogenetic assessment of data. We based our classification on that of Rudolf Schlechter as the most complete and widely accepted today. We found that the anatomy of plants in subtribe Dendrobiinae reflects a high degree of morphological diversity, and many of the anatomical characters appear to be homoplasous. When these anatomical data are used to interpret the systematic relationships among the genera, they indicate thatDendrobiumis not monophyletic and thatCadetiaandPseuderiaare apparently nested within the structure ofDendrobiumwhen sectionGrastidiumis chosen as a functional outgroup. Lack of resolution in the strict consensus tree illustrates the difficulty of determining the phylogenetic relationships of many of Schlechter's sections using anatomical characters. Nevertheless, we recommend that his sectional classification, with appropriate modifications based on available data, be retained for the present, pending a more detailed understanding of the phylogeny of Dendrobiinae based on morphology, micromorphology, anatomy, and DNA studies.
This introduction contains a short history of the study of the Quaternary of Colombia during the last fifteen years, and the history (and some results) of the present project, that started in 1967. The Department of Palynology of the University of Amsterdam carries out this project with grants from the Netherlands Foundation for the Advancement of Tropical Research (WOTRO), with close collaboration of other Dutch institutes and of the following Colombian institutions: Instituto Nacional de Investigaciones Geológico-Mineras (Ingeominas), Instituto de Ciencias Naturales of the Universidad Nacional (Bogotá) and the Instituto Colombiano de Antropología. A bibliography on or of interest to the Quaternary of Colombia is added.
Models of abundances of species per genus were tested against data from samples representing the major vegetation zones of the high Andes (paramo, puna, austral alpine). Abundance models (broken stick, log normal, geometric series, and log series) were used to assess alternative hypotheses. Potential sources of genera now present in the sample areas were compared, and coefficients of similarity were computed between these samples and between each of them and two North American high-elevation floras. Propagule types in the Andean samples were also scored to see if methods of fruit dispersal differed. All areas fit the geometric series model if abundance plots of ranked genera were compared, but results were heavily influenced by the large number of genera represented by only one species. Both the puna and austral alpine samples fit the log series models, indicating that the habitats of these areas are relatively uniform and that arrival of propagules was random over time. The lack of a fit of the Colombian data to the log series or log normal models is due primarily to a large number of species-rich genera relative to other areas. Findings support the hypothesis that there has been a pronounced level of autochthonous speciation in the Colombian Andes relative to other areas, though similarities in climate can be as important as distance in determining the composition of some Andean floras. -from Authors