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Composition and Origins of the World's Tropicalpine Floras
Abstract
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
... These plants are characterized by the predominance of small thick leaves with abundant trichomes which favour water accumulation (Llambí et al., 2012). Páramo soils are capable of regulating water flow from precipitation and snow melting from the glaciers (Mena et al., 2000), allowing their permanent use for irrigation, hydropower generation, and agricultural production (Smith and Cleef, 1988;Hofstede et al., 2014;Malagón and Pulido, 2000). Due to the great accumulation of organic matter in soils favoured by the cold and humid climate as well as by the low atmospheric pressure (Buytaert et al., 2006b), the páramo ecosystem is considered as a globally important reservoir of organic carbon and a natural mitigator of climate change (Winckell et al., 1991;Hofstede et al., 2014;Mena et al., 2000). ...
... In terms of altitudinal range, páramo ecosystems located at the centre and north of the country are generally found above the 3,500 m.a.s.l., whereas páramo ecosystems located at the south (Azuay and Loja provinces) are found at 2,800/3,000 m.a.s.l. (Hofstede et al., 2014;Smith and Cleef, 1988). ...
... The Andean páramo ecosystems are considered to have the richest tropical mountain flora in the world (Smith and Cleef, 1988). This vegetation is characterized by a high degree of endemism in terms of species and genera (Sklenar and Ramsay, 2001). ...
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.
... The Western East African Mountain Cluster (comprising the Virungas and Ruwenzoris) has 339 species, and the Northern East African Mountain Cluster (comprising the Imatong and the Ethiopian highlands) has 306 species. Floristically, the West African Mountain Cluster is sufficiently distinct from the remainder of the Afro-alpine to be considered its own sub-region within the Afro-alpine Linder, 2014, confirming Smith andCleef, 1988). Hedberg (1964) suggested that the Ethiopian component (most of Gehrke and Linder's, 2014 Northern East African Mountain Cluster) should be its own subgroup due to the absence of Dendrosenecio and most shrubby Alchemilla, and the unique presence of Primula and Rosa, although these differences are not enough to statistically alter Gehrke and Linder's (2014) analysis (further fieldwork, aligned with phylogenetically weighted approaches and standardized field methods in the generally poorly explored Ethiopian Highlands, may change this however). ...
... However, based on Maitland's (1932) descriptions of alpine communities and more recent work by Cheek et al. (1996), two species (Helichrysum mannii and Pentameris pictigluma var. mannii) would qualify as true Afro-alpine endemics from Mount Cameroon, apparently being confined to elevations above 3600 m. Smith and Cleef (1988), for example used 2985 m as the lower limit for data from Mount Cameroon for their global tropical alpine analysis. Mount Meru also deserves mention in that-although Gehrke and Linder (2014) consider it to have no Afro-alpine endemics-Afro-alpine-associated endemics certainly occur there (Knox, 2005). ...
... When compared in a species-area relationship to other tropical alpine regions in the world (i.e., the Páramo, the highlands of New Guinea, and Oceania; Gehrke and Linder, 2014;Costin et al., 1979;Pickering et al., 2008;Sklenář et al., 2011;Royen, 1979; Fig. 8), the Afro-alpine Zone is relatively species-poor (for flowering plants) and the Páramo is the most species diverse (Smith and Cleef, 1988;Sklenář et al., 2011). Gehrke and Linder (2014) note that even when accounting for area (i.e., richness) the Afro-alpine is still species-poor (Smith and Cleef, 1988). ...
The Afro-alpine Zone is a fragmented vegetation type that occurs above 3200 m elevation on 14 scattered mountains and covers some 4525 km2 in tropical Africa. Defined by the strong diurnal climate of “summer every day and winter every night,” the Afro-alpine Zone is typified by a unique flora characterized by Giant Groundsel and Giant Lobelia species. The Afro-alpine Zone is mostly concentrated in the eastern region of the continent, with a single western occurrence on Mount Cameroon. It is estimated that the Afro-alpine region harbors between 515 and 521 species of flowering plants, 52 fern species, and > 277 moss species, with endemism levels around 35% for flowering plants and 30% for mosses. This represents moderate diversity and richness compared to other tropical alpine areas such as the Páramos of the South American Andes and the highlands of New Guinea. Typical plant communities in the Afro-alpine are tussock- and shrub-dominated grasslands and alpine bogs or fens, in which are embedded communities of Giant Lobelias and particularly Giant Groundsels. Biogeographically, the evolution of Afro-alpine diversity appears to be driven by age, size, and the geographical proximity of the mountains to each other, similar to the processes described by the General Dynamic Model for oceanic islands but overall much more complex. Due to the difficulty of exploration in some of these mountains and the limitation and biases of the available literature, there is work to be done in terms of finalizing data on the Afro-alpine biotic composition and determining its underlying biogeographic history. Understanding these processes may provide important insights on the conservation of these unique habitats, which are especially threatened by immediate human activities (e.g., overuse of fire) and anthropogenic-driven climatic change.
... Plants adapted to high elevations generally cannot survive at low elevations and vice versa. Alpine-like climate regions in general and those of the Tropics in particular, are therefore considered akin to isolated oceanic islands (Smith and Cleef 1988). ...
... Tropical alpine-like areas are defined as regions located above the natural high-altitude treeline, that is the upper limit of tall upright, woody life forms, within 23°26'N, 23°26'S (Smith and Young 1987;Smith and Cleef 1988;Smith 1994;Rundel et al. 1994;Körner 2003, Nagy andGrabherr 2009). Mountains, especially those in the Tropics, show distinct changes in life conditions with elevation and the rise of isotherms as one moves towards the equator. ...
... Several studies have assessed the origin of plant lineages in one or more tropical alpinelike regions, mostly summarising their data by genus (Engler 1879(Engler , 1892Hedberg 1965;Smith 1975;Smith and Cleef 1988;Beaman and Beaman 1990;Nagy and Grabherr 2009;Sklenář et al. 2011Sklenář et al. , 2014 and more rarely using phylogenetic evidence (Sklenář et al. 2011). Most studies reflect a strong notion of (broad) climatic niche conservatism within genera. ...
Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The analysis presented here shows that the importance of in situ speciation in tropical alpine-like areas has been underestimated. Additionally and contrary to widely held opinion, the impact of dispersal from other regions with alpine-like environments is relatively minor compared to that of immigration from other biomes with a temperate (but not alpine-like) climate. This suggests that establishment in tropical alpine-like regions is favoured by preadaptation to a temperate, especially aseasonal, freezing regime such as the cool temperate climate regions in the Tropics. Furthermore, emigration out of an alpine-like environment is generally rare, suggesting that alpine-like environments – at least tropical ones – are species sinks.
... Endemism is remarkably high, 80% at the species level for vascular plants (Hedberg 1957;Gehrke and Linder 2014) and 64% for mosses (Spence and Pocs 1988). In spite of the high degree of fragmentation, the mountain floras have many species in common and show close relationships with remote temperate regions in the northern and southern hemispheres (Hedberg 1951(Hedberg , 1970Smith and Cleef 1988;Gehrke and Linder 2009). It has been suggested that the isolation among these mountain floras may be stronger than that among oceanic islands, where ocean currents may play a role as an interconnecting dispersal agent (Hedberg 1970). ...
... How the sky island biotas evolved and how similarities among mountain systems were established and maintained over time have been intensely discussed in the literature (Hedberg 1951(Hedberg , 1957(Hedberg , 1970Smith and Cleef 1988; Harmsen et al. 1991;Gottelli et al. 2004;Koch et al. 2006;Ehrich et al. 2007;Umer et al. 2007;Popp et al. 2008;Gehrke and Linder 2009, 2011Sklenář et al. 2014). The proportion of shared species generally correlates with the geographic distance among the mountains (Gehrke and Linder 2014;Sklenář et al. 2014). ...
... The proportion of shared species generally correlates with the geographic distance among the mountains (Gehrke and Linder 2014;Sklenář et al. 2014). The more geographically isolated the mountains are, the more endemic taxa they harbour and the poorer they are in species number (Smith and Cleef 1988;Harmsen et al. 1991;Gehrke and Linder 2014). Colonization patterns thus seem to be closely associated with geographic distance. ...
The tropical alpine ecosystem in eastern Africa is highly fragmented among biological ‘sky islands’, where populations of frost-tolerant organisms are isolated from each other by a ‘sea’ of tropical lowlands. One-third of the species in the afroalpine flora are exclusively alpine, but the other species can to varying degrees extend into grasslands and open forests of lower vegetation belts. A long-debated question is whether colonization of the alpine zone of these mountains and subsequent intermountain gene flow entirely depend on long-distance dispersal across unsuitable habitats, or whether suitable habitats shifted far enough downslope under past colder climates to form bridges enabling gradual migration. Here we address this question using a classification tree model. We mapped the extent of the current alpine habitat and projected it to the last glacial maximum (LGM) climate to assess whether gradual migration was possible for exclusively alpine taxa during this glacial period, and thus potentially also during earlier Pleistocene glaciations. Next, we modelled landcover under current and LGM climates to assess whether grassland and open forests could have served as migration corridors for alpine taxa that today extend into lower vegetation belts. We estimated that the LGM treeline was about 1000 m lower and the alpine habitat was about eight times larger than that today. At the LGM, we found that most of the currently fragmented alpine habitat of the Ethiopian highlands was interconnected except across the Great Rift Valley, whereas the solitary mountains of East/Central Africa remained isolated for exclusively alpine species. However, for drought-tolerant alpine species that today extend below the treeline, gradual migration through habitat corridors may have been possible among mountains during the dry glacial periods, and possibly also under the current climate before agriculture transformed the low-lying landscapes.
... El páramo es uno de los ecosistemas de montaña con más alta biodiversidad en el mundo (Luteyn, 1999;Muellner-Riehl et al., 2019;Smith y Cleef, 1988) y presenta altos niveles de especiación (Madriñán et al., 2013). Esta alta diversidad puede ser explicada por factores bióticos y abióticos (Pouchon et al., 2018, Perrigo et al., 2020Muellner-Riehl et al., 2019;Guayasamín et al., 2021). ...
... La información recopilada en esta publicación ratifica lo espectacular que es el páramo. Su biodiversidad es alta y tiene más especies que cualquier otro bioma de alta montaña en el mundo(Smith y Cleef, 1988). Sin embargo, el mayor valor de la biodiversidad paramera no está en la riqueza de especies sino en su singularidad, es decir, en el gran número de especies que solamente ocurren allí (las endémicas), una diversidad de ecosistemas y una cantidad de formas de vida que coexisten en un espacio relativamente limitado.Según el análisis de flora incluido en el Capítulo 4, se estima una cantidad de 1735 especies de plantas vasculares en los páramos ecuatorianos. ...
Páramo es un concepto complejo: un ecosistema, un bioma, un paisaje, un área geográfica, una zona de vida, un espacio de producción e inclusive un estado del clima. También es un territorio en disputa y un elemento fundamental de la cultura y la historia. Los páramos ecuatorianos han experimentado un constante cambio durante las últimas décadas. Su paisaje, su extensión, su vegetación, su fauna y su población se han visto alterados y con ellos la percepción que se tiene de los páramos.Este libro es una exploración para entender cómo y por qué el páramo ha cambiado, y cuáles son las consecuencias de este cambio. Creemos que parte de la riqueza del libro está precisamente en presentar no solo conocimientos, sino posiciones, todo lo cual enriquece las discusiones y las perspectivas.
... The adjective ''alpine,'' for example, has become a standard term to describe the high-elevation ecosystems that occupy the higher reaches of mountains, above the climatic tree line. Similarly, ''tropical alpine,'' is used to describe the ecosystems and vegetation that characterize the highelevation landscape of the Northern Andes and other tropical mountains (Hedberg and Hedberg 1979;Smith and Cleef 1988;Christmann and Oliveras 2020). However, this generalized use of ''alpine'' could result in 2 unintended outcomes. ...
... An emblematic example in the wet tropical Andes is the caulescent rosette (genus Espeletia) and tussock-grass-dominated p aramo ( Figure 1). This environment is considered ''tropical alpine'' in scientific literature, just like its dryer southern extension (puna) and its African equivalent on Mount Kenya and Mount Kilimanjaro (Hedberg and Hedberg 1981;Smith and Cleef 1988). However, although these environments fit the basic characteristics of an ''alpine'' life zone, we suggest that the indiscriminate use of this term for such a wide array of ecosystems can be misleading. ...
... Arabis L. by LDD from Asia, Assefa et al. 2007; Hypericum L. from Europe, Meseguer et al. 2013; Lychnis L. from Eurasia, Popp et al. 2008; Erica L. from Europe, Pirie et al. 2019). Colonization from the South since the Pliocene has also been shown for some taxa (Senecio, Kandziora et al. 2017; Stoebe L., Bergh and Linder 2009), but Smith and Cleef (1988) concluded that in general the southern element is poorly developed in the Afroalpine region. ...
... However, to our knowledge, stepping-stone migration from Eurasia to Australasia via Southeast Asian high mountains has so far not been shown for any temperate plant lineage. Also, New Guinea, as the last step of migration into Australasia, has an alpine flora of predominantly Southern Hemispheric origin (Smith and Cleef 1988), illustrating a weaker floristic connection of its alpine flora to the North than to the South. ...
Colobanthus (23 species) and Sagina (30–33 species) together are sister to Facchinia. Whereas Facchinia is distributed in western Eurasia, Colobanthus is almost exclusively distributed in the Southern Hemisphere, and Sagina is distributed in both hemispheres with the highest species diversity in western Eurasia. We examined: 1. Whether Sagina and Colobanthus are monophyletic sister genera, 2. Where the two genera originated and how many times dispersal between hemispheres occurred, and 3. Which colonization routes between hemispheres were taken. We reconstructed the phylogeny of Colobanthus and Sagina using nuclear ribosomal internal transcribed spacer (ITS) and two plastid spacers (cpDNA) of altogether 158 ingroup samples of 45 species, and performed molecular dating and ancestral area reconstructions. Sagina and Colobanthus were confirmed as monophyletic sister genera. Biogeographical reconstructions based on ITS and cpDNA showed that Sagina reached the Southern Hemisphere in Australasia or in Africa. For Colobanthus, patterns were less clear and less well-supported: ITS showed Australasia as the region of entry, but cpDNA implied that the Southern Hemisphere may have been entered in America. The extant distributions and the biogeographical histories of Colobanthus and Sagina show both similarities and dissimilarities. This illustrates that biogeographical histories, even of closely related and ecologically very similar lineages, can be highly idiosyncratic.
... 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.
... In the tropical Andes and Central America, a group of ecosystems known as páramo (Hofstede and Llambí, 2020)are situated above the tree line (at ∼3000 m a.s.l.) and below the glaciers (where these are present; at ∼5000 m a.s.l.). Páramo landscapes are molded by volcanic and glacial and periglacial activity (Luteyn, 1992;Smith and Cleef, 1988), as well as by human activity (White, 2013). Given the high elevation location and biophysical characteristics of páramo, its water resources support and regulate the water supply for domestic, industrial, agricultural, and recreational use, as well as for hydropower energy generation (Buytaert et al., 2006a;Célleri and Feyen, 2009). ...
Interdisciplinary knowledge is necessary to achieve sustainable management of natural resources. However, research is still often developed in an exclusively disciplinary manner, hampering the capacity to holistically address environmental issues. This study focuses on páramo, a group of high-elevation ecosystems situated around ∼3000 to ∼5000 m a.s.l. in the Andes from western Venezuela and northern Colombia through Ecuador down to northern Peru, and in the highlands of Panama and Costa Rica in Central America. Páramo is a social-ecological system that has been inhabited and shaped by human activity since ∼10,000 years BP. This system is highly valued for the water-related ecosystem services provided to millions of people because it forms the headwaters of major rivers in the Andean-Amazon region, including the Amazon River. We present a multidisciplinary assessment of peer-reviewed research on the abiotic (physical and chemical), biotic (ecological and ecophysiological), and social-political aspects and elements of páramo water resources. A total of 147 publications were evaluated through a systematic literature review process. We found that thematically 58, 19, and 23 % of the analyzed studies are related to the abiotic, biotic, and social-political aspects of páramo water resources, respectively. Geographically, most publications were developed in Ecuador (71 % of the synthesized publications). From 2010 onwards, the understanding of hydrological processes including precipitation and fog dynamics, evapotranspiration, soil water transport, and runoff generation improved, particularly for the humid páramo of southern Ecuador. Investigations on the chemical quality of water generated by páramo are rare, providing little empirical support to the widespread belief that páramo environments generate water of high quality. Most ecological studies examined the coupling between páramo terrestrial and aquatic environments, but few directly assessed in-stream metabolic and nutrient cycling processes. Studies focused on the connection between ecophysiological and ecohydrological processes influencing páramo water balance are still scarce and mainly related to the dominant vegetation in the Andean páramo, i.e., tussock grass (pajonal). Social-political studies addressed páramo governance and the implementation and significance of water funds and payment for hydrological services. Studies directly addressing water use, access, and governance in páramo communities remain limited. Importantly, we found only a few interdisciplinary studies combining methodologies from at least two disciplines of different nature despite their value in supporting decision-making. We expect this multidisciplinary synthesis to become a milestone to foster interdisciplinary and transdisciplinary dialogue among individuals and entities involved in and committed to the sustainable management of páramo natural resources. Finally, we also highlight key frontiers in páramo water resources research, which in our view need to be addressed in the coming years/decades to achieve this goal.
... The relative frequency indicates the relationship of the absolute records of a species and gel number togsuch of records of all species in this altitudinal range presents Calamagrostis intermediate 17.78%, very similar to(35) in which it is observed that the most important species at 3,800-4,000 m.a.s.l. is Calamagrostis intermedia with 19.41%, because it has the highest values in relative frequency with 5.19%.With respect to the height of 3440 meters above sea level it can be observed that the Rosaceae family has a high percentage followed by the Asteraceae family, According to studies conducted by Smith & Cleef,(37), in the altitudinal range of 3400 to 3500 meters above sea level the most representative families are Rosaceae, Asteraceae and Geraniaceae. According to Ramírez(38) andCaranqui et al. (39), confirms the dominance of the family Asteraceae in genus and species. ...
The ecosystems of the páramos are home to a high number of endemic species that are the result of extraordinary events of radiation, diversification and geographical isolation, the presence or absence of some plant species of the páramo are due to the adaptation to physical or environmental variables, the natural grasslands enjoy characteristics that make them unique and of great ethnobotanical importance, since they provide very appreciable ecosystem services, therefore, the floristic diversity to different strata in the natural grasslands of the Ichubamba Yasepan protected area was analyzed. For this two different altitudes ranging from 3440 m.a.s.l. to 3840masl were taken.To collect data from the floristic inventory, part of the proposed methodology of the GLORIA Research Project was applied, in which 5x5 m quadrants were implanted randomly at every 400 m of altitude and subquadrants of 1x1 m. In each quadrant, samples of the plant species that were found in the study area were collected, which were taken to the ESPOC herbariumfor the respective taxonomic identification and quantification of floristic diversity. A database was elaborated and the analysis of principal components was applied and it was carried out by the estimation method thatc entraliza the variables by subtracting from each value the mean of the variable to which it belongs, the Biplot type was also used: Normalized main row (RMP- Biplot) and Cluster K-means. Therefore, we worked with the free software Multbiplot.The results obtained showed at the height of 3840 m.s.n.m 16 families and 23 species were registered, the species that presents the highest numerical value with respect to DR%, FR% and IVI is Calamagrotis intermedia. At the height of 3440 m.a.s.l. they registered 11 families and 19 species, the species that presents the highest numerical value in DR%, FR% and IVI is Lachemilla orbiculata, with greater dominance. According to the Simpson dominance index at 3840 m.a.s.l. it has a high diversity and the Shannon index showed that there is a medium diversity. It is concluded according to the Simpson dominance index at the height of 3440 m.a.s.l. has a high diversity and the Shannon index indicates that there is a medium diversity. According to Sorensen shows that the two altitudinal ranges studied is similar and finally for the analysis of the main components plant species of stratum 3840 m.a.s.l. They have high values in terms of coverage which indicates that the vegetation cover of the stratum with a height of 3840 meters above sea level is more abundant and more diverse for axis 1 represents 61.13% of the analysis and axis 2 represents 28.63%.
... In the tropical Andes and Central America, a group of ecosystems known as páramo (Hofstede and Llambí, 2020)are situated above the tree line (at ∼3000 m a.s.l.) and below the glaciers (where these are present; at ∼5000 m a.s.l.). Páramo landscapes are molded by volcanic and glacial and periglacial activity (Luteyn, 1992;Smith and Cleef, 1988), as well as by human activity (White, 2013). Given the high elevation location and biophysical characteristics of páramo, its water resources support and regulate the water supply for domestic, industrial, agricultural, and recreational use, as well as for hydropower energy generation (Buytaert et al., 2006a;Célleri and Feyen, 2009). ...
Interdisciplinary knowledge is necessary to achieve sustainable management of natural resources. However, research is still often developed in an exclusively disciplinary manner, hampering the capacity to holistically address environmental issues. This study focuses on páramo, a group of high-elevation ecosystems situated around ∼3000 to ∼5000 m a.s.l. in the Andes from western Venezuela and northern Colombia through Ecuador down to northern Peru, and in the highlands of Panama and Costa Rica in Central America. Páramo is a social-ecological system that has been inhabited and shaped by human activity since ∼10,000 years BP. This system is highly valued for the water-related ecosystem services provided to millions of people because it forms the headwaters of major rivers in the Andean-Amazon region, including the Amazon River. We present a multidisciplinary assessment of peer-reviewed research on the abiotic (physical and chemical), biotic (ecological and ecophysiological), and social-political aspects and elements of páramo water resources. A total of 147 publications were evaluated through a systematic literature review process. We found that thematically 58, 19, and 23 % of the analyzed studies are related to the abiotic, biotic, and social-political aspects of páramo water resources, respectively. Geographically, most publications were developed in Ecuador (71 % of the synthesized publications). From 2010 onwards, the understanding of hydrological processes including precipitation and fog dynamics, evapotranspiration, soil water transport, and runoff generation improved, particularly for the humid páramo of southern Ecuador. Investigations on the chemical quality of water generated by páramo are rare, providing little empirical support to the widespread belief that páramo environments generate water of high quality. Most ecological studies examined the coupling between páramo terrestrial and aquatic environments, but few directly assessed in-stream metabolic and nutrient cycling processes. Studies focused on the connection between ecophysiological and ecohydrological processes influencing páramo water balance are still scarce and mainly related to the dominant vegetation in the Andean páramo, i.e., tussock grass (pajonal). Social-political studies addressed water governance and the implementation and significance of water funds and payment for hydrological services. Studies directly addressing water use, access, and governance in páramo communities remain limited. Importantly, we found only a few interdisciplinary studies combining methodologies from at least two disciplines of different nature despite their value in supporting decision-making. We expect this multidisciplinary synthesis to become a milestone to foster interdisciplinary and transdisciplinary dialogue among individuals and entities involved in and committed to the sustainable management of páramo natural resources. Finally, we also highlight key frontiers in páramo water resources research, which in our view need to be addressed in the coming years/decades to achieve this goal.
... Rocky outcrops are generally recognized as one of the hotspot centers of diversity and endemism in the world (Smith & Cleef, 1988; Barthlott et al., 1993;Alves & Kolbek, 1994). These environments usually contain a series of severe conditions such as high UV exposure, diurnal thermal variations, constant winds, high evaporation and transpiration, low water retention and discontinuous soils that mostly provide suitable microenvironments for plant species adapted to such extreme ecosystems (Porembski & Barthlott, 2000;Scarano, 2002). ...
Abstract
Question: Rocky outcrops generally restrict recruitment and survival of plant species due to their environmental conditions including low soil moisture, nutrient shortages and microclimate harshness. Under such severe conditions, nurse plants may play critical roles to preserve plant biodiversity. Although, the nurses’ effects on plant biodiversity are fully understood in different major biomes, the relative effects of abiotic factors and nurse plants as important factors have rarely been studied in the rocky outcrops, and compared to their surrounding rangelands. Therefore, we sought to assess the effects of two dominant shrub species (Artemisia aucheri Boiss. and Prunus pseudoprostrata Pojark) on all biodiversity components including taxonomic, functional and phylogenetic diversity across some environmental gradients such as precipitation and soil gradients in rocky outcrops and their surrounding rangelands.
Location: The study was conducted in six sites located in rocky outcrops and their surrounding rangelands across precipitation gradient (160-910 mm) and under different soil fertility levels in northern Iran.
Methods: We established 80 1m2 (1m x 1m) plots in each site with respect to presence the nurse shrubs, and measured biodiversity components within the plots using Rao Q entropies (q0, q1 and q2) and mean pairwise distance (MPD) indices. Relative interaction index (RII) was also calculated to quantify the interaction type and intensity. Finally, variation partitioning analysis was performed to determine relative importance of biotic interactions and abiotic factors such as precipitation, EC and phosphorus on structuring biodiversity components.
Results: Plant-plant interactions and abiotic factors consistently influenced different components of biodiversity in rocky outcrops and their surrounding rangelands. However, nurse shrubs showed stronger effects on plant biodiversity than abiotic factors by providing suitable microenvironments to harbor less tolerant plant species under the severe conditions of outcrops. In addition, microhabitats beneath nurse shrubs significantly responded to soil electrical conductivity (EC) and precipitation gradients, with a decrease in competition intensity under intermediate levels of the gradients. In contrast, nurse shrubs negatively affected different components of biodiversity, with a decrease in biodiversity under intermediate levels of environmental gradients in surrounding rangelands.
Conclusions: Our findings show critical roles of nurse shrubs to maintain plant biodiversity in rocky outcrops depending on their growth form and biodiversity component considered. In this case, nurse shrubs could reduce double environmental filtering consistent with establishing functional paradox trade-off to support a wide range of plant species with functionally divergent relatedness.
... Tropical Montane Cloud Forests (TMCFs) comprise ~2.5% of global tropical forest area (Bubb et al., 2004), and harbour a disproportionately large number of the world's plant species and endemisms (Bubb et al., 2004;Gentry, 1992). Additionally, they possess a unique flora, comprising distinct biogeographical groups from warm-adapted tropical and cool-adapted temperate origins (Raven & Axelrod, 1974;Smith & Cleef, 1988). World-wide, TMCFs have been considered one of the most vulnerable ecosystems to climate change because of their restricted distribution to the top of tropical mountains and their specific climatic envelope, which is associated with frequent cloud immersion (Bruijnzeel, 2001;Hamilton, 1995). ...
Tropical montane cloud forests (TMCF) have unique climatic conditions, which allow the coexistence of plant lineages with different phytogeographical origins from tropical versus temperate climates. Future climate projections suggest TMCFs will be subjected to increasing drought stress due to fog uplift and higher temperatures, possibly leading to tree mortality and local extinctions, and consequently changes in forest composition and functioning. Characterizing community functional composition, trade‐offs among traits and the drivers of community assembly is of utmost importance to improve our capacity to predict the response of montane plant communities to forecast climate change.
Here, we aimed to test whether species from different phytogeographical origins (i.e. tropical – evergreen × deciduous − and temperate) differ in drought vulnerability and how the coexistence of these groups change the hydraulic composition of TMCFs. We used a framework based on measurements of key hydraulic traits (i.e. xylem embolism resistance, hydraulic safety margin, stomata control, turgor loss point, minimum water potential) of 16 dominant species (>70% of the forest basal area) within a TMCF in the Atlantic Rain Forest Domain in southeast Brazil. We used community‐weighted means to model whether removing each species group would change the community hydraulic functional composition.
Temperate, tropical deciduous and tropical evergreen groups differ in their hydraulic functioning and these differences explain forest functional composition and taxa dominance. Temperate and tropical deciduous taxa were consistently more vulnerable hydraulically (i.e. lower safety margins and embolism resistance). The coexistence of different phytogeographical lineages is a key determinant of TMCF hydraulic composition. We also used models including phylogeny to evaluate the variation of hydraulic traits across phytogeographical groups, and the results suggest some niche conservatism associated with plant hydraulic functioning.
Our results provide evidence of the importance of species phytogeographical origin on TMCF functioning, and niche conservatism in the evolution of hydraulic traits. The higher drought vulnerability observed in temperate group might be a mechanistic explanation for the restriction of temperate taxa distribution to wetter places during past colder and drier climate. Thus, we suggest hydraulic functional traits may be useful to predict future dynamics of TMCFs under changing climatic conditions.
... The lowermost, montane forest belt is followed by an ericaceous belt that precedes the afro-alpine belt (Hedberg 1969(Hedberg , 1970. The majority of the afro-alpine taxa have their congeners in temperate and alpine regions elsewhere in the world (Smith and Cleef 1988;Assefa et al. 2007;Devos et al. 2010;Gehrke et al. 2016;Gizaw et al. 2016a;Kandziora et al. 2016), but some of them have their closest relatives in adjacent areas at lower elevations (Galbany-Casals et al. 2014;Nürk et al. 2015). The afro-alpine flora comprises some 77% endemic vascular plant species (Hedberg 1961;Gehrke and Linder 2014), which may be particularly vulnerable toward habitat destruction and climate change (Brochmann et al. 2021). ...
Alpine plant radiations are common across all major mountain systems of the world, and have been regarded as the main explanation for the species diversity found within these areas. To study the mechanisms behind the origin of this diversity, it is necessary to determine phylogenetic relationships and species boundaries in radiating alpine groups. The genus Dendrosenecio (Asteraceae) is an iconic example of a tropical-alpine plant radiation in the East African high mountains. To this date, limited sampling of molecular markers has resulted in insufficient phylogenetic resolution and infrageneric classification, hindering a comprehensive understanding of the drivers of diversification. Here, we used Hyb-Seq and the Compositae1061 probe set to generate targeted nuclear and off-target plastid DNA data for 42 samples representing all currently accepted 11 species. We combined coalescent methods and paralogy analysis to infer phylogenetic relationships, estimate divergence times and evaluate species boundaries. Lineage differentiation in Dendrosenecio seems to have occurred between the Late Miocene and the Pleistocene, starting when the first high elevation habitats became available in East Africa. We retrieved four major clades corresponding to four geographically distant mountain groups, testifying the importance of allopatric speciation in the early diversification of the group. Cytonuclear discordance suggested the occurrence of historical hybridization following occasional long-distance dispersal between mountain groups. The species delimitation analysis favored 10 species, but only five were fully supported, suggesting that population-level studies addressing processes such as ecological speciation and hybridization after secondary contact are needed to determine the current diversity found in the genus.
... Trait adjustments toward improved resource conservation (shorter plants with greater LDMC and thicker leaves) occurred in tropical rosettes, whereas the traits of Holarctic rosettes varied little along the elevation gradient. Our interpretation is that the biogeographic origin of the tropical rosettes from warm, tropical environments, where productivity is a priority and not tolerance to abiotic stress, results in a poorer evolutive adaptation to cold (Donoghue 2008;Smith and Cleef 1988). This translates into higher aboveground trait variation in tropical rosettes than in Holarctic rosettes, which are preadapted to cold environments (Sklenář et al. 2012). ...
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.
... The páramos are the largest extension of tropical alpine ecosystems, forming a discontinuous belt throughout the northern Andes, with outliers in Panama and Costa Rica. The páramo has the most diverse mountain flora in the world (Smith & Cleef, 1988), and these grasslands sustain ecological processes, carbon storage, and supply water for millions of people, agriculture and industry at lower latitudes (Buytaert et al., 2011). ...
Questions
Fire suppression policies have been widely adopted in the páramo grasslands of the northern Andes to protect their biodiversity and ecosystem services. Páramos have been regularly burned for many years, and it is not clear how páramo vegetation will respond to significant changes in their fire regimes. This study investigates differences in plant growth form composition, light levels and soil temperatures in páramo plots representing a range of recovery times since the last fire.
Location
Reserva Ecológica El Ángel and La Bretaña Nature Reserve, Carchi, Northern Ecuador.
Methods
We assessed the frequency of ten páramo growth forms, vegetation height, soil temperature, and light intensity in fifteen fire sites with historical records of fire (<1–15 years since fire), and one recently unburned site (at least 40 years since fire). A chronosequence of sites was used to assess potential changes in plant community composition in post‐fire succession of páramo.
Results
The recovery of páramo vegetation after fire comprised three phases: initial recruitment with high growth form diversity, followed by reduced diversity, light and soil temperatures in dense tussock vegetation, and ultimately canopy height stratification with a return of diversity. All but one of the plant growth forms were represented in each of the three phases, and the changes reflected differences in relative abundance.
Conclusions
Post‐fire páramo succession is characterised by clear shifts in the relative abundance of plant growth forms, ending with (co‐)dominance of upright shrubs. The long‐term consequences of such shifts for biodiversity and ecosystem function, given the widespread adoption of fire suppression policies in the páramo, need careful, evidence‐based consideration.
... The páramos are the largest extension of tropical alpine ecosystems, forming a discontinuous 42 belt throughout the northern Andes, with outliers in Panama and Costa Rica. The páramo has 43 the most diverse mountain flora in the world (Smith and Cleef 1988), and these grasslands 44 sustain ecological processes, carbon storage, and supply water for millions of people, 45 agriculture and industry at lower latitudes (Buytaert et al. 2011). 46 Fires are the most significant human impact in the páramos ( Ramsay 57 2001). ...
Questions
Fire suppression policies have been widely adopted in the páramo grasslands of the northern Andes to protect their biodiversity and ecosystem services. Páramos have been regularly burned for many years, and it is not clear how páramo vegetation will respond to significant changes in their fire regimes. This study investigates differences in plant growth form composition, light levels and soil temperatures in páramo plots representing a range of recovery times since the last fire.
Location
Reserva Ecológica El Ángel and La Bretaña Nature Reserve, Carchi, Northern Ecuador.
Methods
We assessed the frequency of ten páramo growth forms, vegetation height, soil temperature, and light intensity in fifteen fire sites with historical records of fire (<1 – 15 years since fire), and one recently unburned site (at least 40 years since fire). A chronosquence of sites was used to assess potential changes in plant community composition in post-fire succession of páramo.
Results
The recovery of páramo vegetation after fire comprised three phases: initial recruitment with high growth form diversity, followed by reduced diversity, light and soil temperatures in dense tussock vegetation, and ultimately canopy height stratification with a return of diversity. All but one plant growth forms were represented in each of the three phases, and the changes reflected differences in relative abundance.
Conclusions
Post-fire páramo succession is characterized by clear shifts in the relative abundance of plant growth forms, ending with (co-)dominance of upright shrubs. The long-term consequences of such shifts for biodiversity and ecosystem function, given the widespread adoption of fire suppression policies in the páramo need careful, evidence-based consideration.
... Los páramos son ecosistemas que se reconocen por su alta diversidad (Smith & Cleef, 1988;Sklenár, Hedberg & Cleef, 2014), comparados con otros ecosistemas similares en el mundo. Son propios del Neotrópico y se ubican en la parte alta de las montañas entre la franja de bosque andino y la parte más baja de las nieves (Rangel-Ch, 2000;Hofstede, Segarra, & Mena, 2003;Llambí & Cuesta, 2014). ...
Composition and structure of the forest-páramo transition in the Guantiva-La Rusia corridor (Colombia). The altitudinal forest-paramo transition area, in its lower limit is characterized by the transition through the high Andean forest to high and low forest bushes, and is upper limit to the turnover between the low shrubs to herbaceous. Samplings were carried out in three localities of the Guantiva-La Rusia complex in the Western flank, through a 100 m 2 parcels for the forest coverage and 50 m 2 for the shrub and the herbaceous coverages, with an altitudinal difference of 100 m between altitudinal areas. We recorded 70 families, distributed in 157 genera and 302 species. The Asteraceae family were the most diverse with 16 genera and 39 species; likewise, Miconia was the most diverse with 14 species. Diversity indexes revealed that the most dominant in species composition were the herbaceous areas; regarding to diversity, the Onzaga-Susacon forest is 1.9 and 1.3 times more diverse than Belen and Duitama respectively. This research allowed identifying the transitional area through the transformation of the vascular flora physiognomy and diversity in the altitudinal gradient Western flank complex, that transition area is in Duitama between 3 394-3 516 m, in Belen 3 411-3 649 m and in Onzaga-Susacon 3 300-3 390 m.
... Los páramos son ecosistemas que se reconocen por su alta diversidad (Smith & Cleef, 1988;Sklenár, Hedberg & Cleef, 2014), comparados con otros ecosistemas similares en el mundo. Son propios del Neotrópico y se ubican en la parte alta de las montañas entre la franja de bosque andino y la parte más baja de las nieves (Rangel-Ch, 2000;Hofstede, Segarra, & Mena, 2003;Llambí & Cuesta, 2014). ...
Composition and structure of the forest-páramo transition in the Guantiva-La Rusia corridor (Colombia). The altitudinal forest-paramo transition area, in its lower limit is characterized by the transition through the high Andean forest to high and low forest bushes, and is upper limit to the turnover between the low shrubs to herbaceous. Samplings were carried out in three localities of the Guantiva-La Rusia complex in the Western flank, through a 100 m 2 parcels for the forest coverage and 50 m 2 for the shrub and the herbaceous coverages, with an altitudinal difference of 100 m between altitudinal areas. We recorded 70 families, distributed in 157 genera and 302 species. The Asteraceae family were the most diverse with 16 genera and 39 species; likewise, Miconia was the most diverse with 14 species. Diversity indexes revealed that the most dominant in species composition were the herbaceous areas; regarding to diversity, the Onzaga-Susacon forest is 1.9 and 1.3 times more diverse than Belen and Duitama respectively. This research allowed identifying the transitional area through the transformation of the vascular flora physiognomy and diversity in the altitudinal gradient Western flank complex, that transition area is in Duitama between 3 394-3 516 m, in Belen 3 411-3 649 m and in Onzaga-Susacon 3 300-3 390 m.
... Los páramos son ecosistemas que se reconocen por su alta diversidad (Smith & Cleef, 1988;Sklenár, Hedberg & Cleef, 2014), comparados con otros ecosistemas similares en el mundo. Son propios del Neotrópico y se ubican en la parte alta de las montañas entre la franja de bosque andino y la parte más baja de las nieves (Rangel-Ch, 2000;Hofstede, Segarra, & Mena, 2003;Llambí & Cuesta, 2014). ...
La franja de transición altitudinal bosque-páramo, en su límite inferior se caracteriza por el cambio de bosque altoandino a arbustales de portes alto y bajo, y en su límite superior al recambio entre arbustal de bajo porte a herbazal; se realizaron muestreos en tres localidades del flanco occidental del complejo de páramos Guantiva – La Rusia, mediante parcelas de 100 m2 para la cobertura de bosque y 50 m2 para arbustal y herbazal, con una diferencia altitudinal de 100 m aproximadamente entre las estaciones. Se encontraron 70 familias, distribuidas en 157 géneros y 302 especies, siendo Asteraceae la familia más diversa con 16 géneros y 39 especies, a su vez, Miconia el género más diverso con 14 especies. Los índices de diversidad revelaron que las estaciones de herbazales, para las tres localidades fueron las más dominantes; en cuanto a la diversidad el bosque de Onzaga-Susacón registra 1.9 y 1.3 veces, más diversidad que Belén y Duitama respectivamente. El presente estudio permitió identificar la franja de transición a partir del cambio en la fisionomía y diversidad de la flora vascular en el gradiente altitudinal del flanco occidental del complejo, dicha franja se ubica en Duitama entre los 3 394 y 3 516 m de altitud, en Belén entre los 3 411 y 3 649 m y en Onzaga-Susacón entre los 3 300 y 3 390 m.
... The Neotropical alpine ecosystem of the "páramo" provides several ecosystem services like water regulation and supply, carbon storage and biodiversity conservation [1,2]. Furthermore, the páramo ecosystem hosts the richest high mountain flora in the world [3], and the fastest average net diversification rates of all 'hotspots' or areas featuring exceptional concentrations of endemic species that are experiencing exceptional loss of habitat [4,5]. According to Hofstede et al. [2], 1,524 species of vascular plants have been registered in the páramo of Ecuador, from which approximately 628 are endemic (15% of Ecuadorian endemic plants). ...
During the 1980s, reforestation programs using exotic species (Pinus spp.) were established in the páramo ecosystem of Ecuador. The aims of this study were: (1) to compare the natural regeneration between pine plantations (Pi) and natural grassland (NG) across an elevational gradient and (2) to identify the attributes of Pi and soil properties that were influencing herbaceous and woody plant composition and their plant cover. In total, six independent Pinus patula (Schltdl. & Cham. plantations (two per each elevation) were selected and distributed in an elevational range (3200-3400, 3400-3600, 3600-3800 m a.s.l.). Adjacent to Pi, plots in NG were established for recording natural regeneration. Both, namely the attributes and the soil samples, were measured in Pi. The results showed that natural regeneration differs significantly between both types of vegetation. As expected, NG holds more plant diversity than Pi; the elevational range showed a clear tendency that there was more herbaceous richness when elevation range increases, while the opposite was found for woody species. Moreover, attributes of Pi influenced herbaceous and woody vegetation, when saturated hydraulic conductivity (Ksat) in the soil, basal area (BA) and canopy density (CD) increased, herbaceous species richness and its cover decreseased; and when Ksat and the acidity in the soil increased, woody plants richness and its cover decreased. The plantations have facilitated the establishment of shade tolerant species. More studies are needed to evaluate if removal with adequate management of pine plantations can improve the restoration and conservation of the native vegetation of the páramo ecosystem.
... This has resulted in a high level of endemism and remarkable plant diversity. It is well documented that this tropical alpine zone is the richest in terms of plant diversity among all alpine landscapes in the world ( Smith and Cleef, 1988;Cuesta et al., 2017). The páramo also exhibits an outstanding functional plant diversity ( ), reflected in a wide range of plant growth-forms including giant rosettes, sclerophyllous shrubs, tussock grasses, nongraminoid herbs, cushion plants and acaulescent rosettes (Hedberg and Hedberg, 1979;Ramsay and Oxley, 1997). ...
... According to Smith and Cleef (1988), the flora above the tree line in tropical mountains is mostly of extra-tropical origin. Subularia and Sagina are of holarctic origin (northern temperate geoelements sensu Hedberg 1986). ...
The wetland vegetation of the Afro-(sub)alpine belt, which is dominated by tussock grassland, has embedded in it ericaceous shrubs, Helichrysum cushions and Carex bogs, which constitute small microhabitats with annuals. A synopsis of these annual turfs is presented in a constancy table, based upon the available plot data (168 relevés), sampled on the tops of the high volcanoes of East Africa (3500–4500 m altitude). The results are compared with similar vegetation types in the Ethiopian Highlands, Drakensberg Mts. and Marion Island (South Africa). Subularia monticola and Crassula granvikii characterize this vegetation type, together with vicarious species from the genera Limosella, Crassula, Sagina, Isolepis and Ranunculus. These short-living herbs regenerate and establish on open patches, created in the perennial turf by cryo- and bioturbation, by needle ice and frost-heaving, and they colonize the shores of oligotrophic lakes with fluctuating water levels, germinating under water (tenagophytes). Geocarpy is an important adaptation to soil movement in the cryoro-tropical thermoclimate. The Afro-tropical Subularia communities share some floristic and ecological characteristics with boreal and subarctic littoral vegetation (Littorellion with Subularia aquatica) and with the Crassuletalia peduncularis-venezuelensis in the oro-tropical belt of the Andes.
... The páramo is the tropical high-elevation ecosystem found between the upper forest-line at ca. 3000-3500 m and the permanent snow-line at ca. 5000 m, occupying an area of about 35,000 km 2 along the Andes of Venezuela, Colombia, Ecuador and Northern Peru, with some outliers in Panama and Costa Rica. Páramos are extraordinarily diverse, hosting a total of 4696 plant species, about 10-20% of the Andean flora (Rangel-Churio 2000), and much more than any other tropical high-elevation flora (Smith and Cleef 1988;Sklenář et al. 2011). Yet páramos are affected by steadily rising intensive human activities such as agricultural practices and mining, as well as by pressures with more diffuse impacts such as tourism, extraction of valuable plants and biological invasions (Sarmiento et al. 2017). ...
Background: Páramos are the high-elevation ecosystems of the humid tropical Andes, characterised by the presence of giant rosettes of the Espeletiinae subtribe (Asteraceae). Forecasted climate change is likely to reduce the extent of the area climatically suitable/occupied currently by Espeletiinae and their elevation distribution patterns.
Aims: The aim of this study was to estimate the potential impacts of forecasted climate change on the geographic distribution (extent of area and elevation distribution patterns) of 28 species of Espeletiinae that have been recorded in the Cordillera de Mérida, Venezuela.
Methods: Six bioclimatic variables, downscaled to a 90 m × 90 m cell size, were used to construct species distribution models (SDM) for the 28 species to model their current and likely future distribution (2070) by using two general circulation models and four representative concentration pathways (RCP).
Results: Nine species were estimated to have potential distribution over less than 1000 km² and five over less than 500 km², in current climatic conditions. Fifteen and eight species had elevation spans narrower than 1000 m and 500 m, respectively. No significant differences in modelled areas or spans were detected between north, central and south sections of the Cordillera de Mérida. Mean ± SE future reduction in the extent of area climatically suitable were estimated between 51.3% ± 6.3% (RCP2.6) and 78.1% ± 5.3% (RCP8.5), coupled with upward range retreat of between 277.8 m ± 27.4 m (RCP2.6) and 762.5 m ± 59.8 m (RCP8.5).
Conclusions: Our study predicts large reductions in modelled area and important upward shifts in the distribution of Venezuelan Espeletiinae by 2070 compared to their current distribution.
... The mountain tops of the tropics harbour ecosystems with similar climatic and ecological conditions; namely, the tropical-Alpine ecosystem in south-eastern Asia (Hnatjuk 1978;Smith and Cleef 1988), the Afro-Alpine belt in tropical Africa (Hedberg 1964(Hedberg , 1970, and the Jalca and Páramo in the Neotropics (Weber 1959;Troll 1968;Luteyn 1999). Their vegetation shows a similar physiognomy, with characteristic plants with giant caulescent rosettes, and includes several representatives of the same families, such as, for example, Poaceae, Asteraceae and Ericaceae (Hedberg 1970;Balslev and de Vries 1991;Smith 1994). ...
We identified biogeographical districts in the Páramo biogeographic province, in the north-western Andes of Colombia, Ecuador and Venezuela, including the Sierra Nevada de Santa Marta in Colombia, above 3000 m ASL. We applied a parsimony analysis of endemicity (PAE) to 8418 distributional data of 4644 vertebrate and angiosperm species, distributed in the north-western Andes and the Sierra Nevada de Santa Marta. Areas analysed were selected according to the hypotheses of several authors.Weobtained a single most parsimonious cladogram, which shows 10 groups of areas (southern Ecuadorian, central Ecuadorian, northern Ecuadorian, Venezuelan, Los Picachos, Sierra Nevada, Santa Inés-Sonsón, Paramillo del Sinú, Cordillera Oriental and Quindío) and a single isolated area (Farallones de Cali). We propose that these areas conform 11 biogeographical districts. The biogeographical districts obtained adjust to the ‘cordilleran pattern’, where páramos of each cordillera are linked together. This study supports the hypothesis
that during different glacial periods, páramos of these cordilleras were connected and, subsequently, separated during interglacial periods.
... Los procesos geológicos que formaron los Andes dieron origen a nuevos ecosistemas, entre ellos el páramo. El páramo es uno de los ecosistemas de alta montaña más rico en vegetación del mundo con una gran biodiversidad y endemismo (Smith y Cleef, 1988). Por su alta diversidad biológica y su importancia biogeográfica, evolutiva, ecológica y económica, el páramo es un ecosistema único y muchas especies que se han adaptado a él no se encuentran en ningún otro lugar (Sklenar et al., 2005). ...
Relaciones filogenéticas de Lachemilla (Focke) Rydb. (Rosaceae) inferidas a partir de secuencias de ADN nuclear y cloroplástico, con énfasis en las especies del norte de Sudamérica. Disertación previa a la obtención del título de Licenciado en Ciencias Biológicas
... Páramo ecosystems provide several ecological functions and environmental services such as the regulation of hydrology, protection from erosion, carbon storage and its function as a biological corridor for many species of flora and fauna (Hofstede et al. 2003, Buytaert et al. 2006. Furthermore, páramos host the richest high mountain flora of the world (Smith and Cleef 1988), being considered as a hotspot within a hotspot (Myers et al. 2000) with a high endemicity and with the fastest diversification rates of all hotspots (Madriñán et al. 2013). In these páramos, climatic factors, orography, age of the substrate, land use or dispersal have an influence on the diversity patterns (Acosta-Solís 1984, Luteyn 1992, Sklenář et al. 2010. ...
Altitudinal gradients involve macroclimatic changes that can affect the diversity of several organisms. We tested the effects of elevation and small-scale variables on the diversity and composition of terricolous communities (lichens and bryophytes) in five páramos in southern Ecuador. The altitudinal range considered (from 2700 to 4000 m a.s.l.) is associated with changes in rainfall, temperature and irradiance. At each páramo, forty 40 x 40 cm2 sample plots were randomly selected in similar areas of vegetation (grass páramo) and conservation status. The presence/absence and cover of lichens and bryophytes were recorded in 200 sample plots. A total of 90 species (46 lichens and 44 bryophytes) were identified. Our results showed that total species richness, lichen and bryophyte richness, Simpson's inverse and Shannon's index were related to elevation and slope. Nevertheless, the response to elevation was dependent on the organism considered. Thus, meanwhile lichens had their maximum richness at the highest elevation (3930 m a.s.l.), bryophytes had a maximum peak at middle elevation (3300 m a.s.l.). Species composition also differed significantly among the five páramos, especially in bryophytes. We conclude that differences in the elevation of these páramos and small-scale variables such as slope significantly affect the diversity and composition of terricolous communities.
... En diferentes ecorregiones del mundo se ha reconocido que los afloramientos rocosos constituyen hábitats particularmente importantes desde el punto de vista de conservación de la biodiversidad por la riqueza de sus endemismos, la presencia de especies raras y su valor como refugio de especies amenazadas (Wardle, 1971(Wardle, , 1991Rogers & Walter, 2002;Burke et al., 2003;Hunter, 2003;de Lange et al., 2004;Wiser & Buxton, 2009;Esgario et al., 2009;Sadler & Bradfield, 2010). El conocimiento de las especies que allí crecen seguidos de estudios sobre su autoecología son prerrequisitos para poder generar acciones serias de conservación (Smith & Cleef, 1988;Barthlott et al., 1993;Alves & Kolbek, 1994;Porembski et al., 1994;Giuletti et al., 1997;Michelangeli, 2000). ...
En las montañas del centro de Argentina, con una intensa fragmentación y reemplazos dela vegetación natural, los afloramientos rocosos constituyen hábitats importantes para la conservaciónde la biodiversidad, como refugios de especies endémicas y raras. En este trabajo se exploró lavariación composicional local de la vegetación en afloramientos de mármoles cálcicos y dolomíticosde las sierras de Córdoba y se compararon las asociaciones entre diferentes tipologías geoquímicas yla composición florística en un gradiente altitudinal. Se relevaron cuatro afloramientos adyacentes detipologías geoquímicas diferentes localizados en diferentes posiciones en un gradiente de altitud desde1000 hasta 1800 msm, estimándose abundancia-cobertura de todas las plantas vasculares en 216censos. Los atributos composicionales estructurales de la vegetación revelaron diferencias significativasentre litologías similares en diferentes estratos altitudinales y entre diferentes litologías para un mismoestrato altitudinal. La composición florística local está relacionada con la tipología geoquímica de losafloramientos y la altitud se sobrepone a ese patrón. Se establecieron relaciones entre la presencia dediferentes especies vegetales y tipologías de rocas calcíticas y dolomíticas de manera independiente asu posición en el gradiente de altitud. Se confirma la importancia de estas variables en la estructuracióndel hábitat y filtrado abiótico de especies y la importancia de su conocimiento para establecer prioridadesen su conservación.
... Fuente: Fotografía tomada por Lizeth Manuela Avellaneda- Torres, 2008 Los páramos forman un corredor interrumpido entre la cordillera de Mérida en Venezuela hasta la depresión de Huancabamba en el norte del Perú, con dos complejos más separados, los páramos en Costa Rica y la Sierra Nevada de Santa Marta, y con una continuidad en el sur, la jalca peruana. (Smith y Cleef 1988, Hofstede 2008. De los 35.303 km 2 de páramo (igual a la superficie de Bélgica), la mayor extensión la tiene Colombia, con 14.434 km 2 , seguida por Ecuador con 12.602 km 2 , Perú con 4.200 km 2 , Venezuela con 2.630 km 2 y Costa Rica con sólo 80 km (Hofstede 2003). ...
... The páramo flora is extremely diverse and considered the richest high mountain flora of the world (Smith & Cleef 1988, Luteyn 1999. Unfortunately, its lichen communities are relatively poorly studied (Sipman 2002a). ...
Ecological studies of five páramos in Azuay and Loja provinces recorded one lichen species new to South America (Bryoria nitidula), five new to Ecuador (Cladonia halei, C. melanopoda, C. merochlorophaea, C. subreticulata, Diploschistes diacapsis), two new to mainland Ecuador (Cladonia grayi, C. pyxidata), and 20 new provincial records. Brief morphological descriptions, with remarks on distribution and ecology, are provided.
... These groups were composed of different plant community assemblages, probably as a result of past geological-biogeographical events Balslev 2005, Sklenář et al. 2014), and current environmental conditions (Jørgensen et al. 2011, Kessler et al. 2011). The differences in plant community composition and abundances between high Andean summits investigated in this study supports previous findings that compared the Puna and Páramo regions (Simpson 1983, Sklenář et al. 2011, Smith and Cleef 1988). However, the high level of community dissimilarity identified between summits could also have been influenced by the limited numbers of study sites together with a relatively low surface area sampled on each summit. ...
The high tropical Andes host one of the richest alpine floras of the world, with exceptionally high levels of endemism and turnover rates. Yet, little is known about the patterns and processes that structure altitudinal and latitudinal variation in plant community diversity. Herein we present the first continental-scale comparative study of plant community diversity on summits of the tropical Andes. Data were obtained from 792 permanent vegetation plots (1 m²) within 50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220 and 5498 m a.s.l. We analyzed the plant community data to assess: 1) differences in species abundance patterns in summits across the region, 2) the role of geographic distance in explaining floristic similarity and 3) the importance of altitudinal and latitudinal environmental gradients in explaining plant community composition and richness. On the basis of species abundance patterns, our summit communities were separated into two major groups: Puna and Páramo. Floristic similarity declined with increasing geographic distance between study-sites, the correlation being stronger in the more insular Páramo than in the Puna (corresponding to higher species turnover rates within the Páramo). Ordination analysis (CCA) showed that precipitation, maximum temperature and rock cover were the strongest predictors of community similarity across all summits. Generalized linear model (GLM) quasi-Poisson regression indicated that across all summits species richness increased with maximum air temperature and above-ground necromass and decreased on summits where scree was the dominant substrate. Our results point to different environmental variables as key factors for explaining vertical and latitudinal species turnover and species richness patterns on high Andean summits, offering a powerful tool to detect contrasting latitudinal and altitudinal effects of climate change across the tropical Andes. Ecography
... stem rosettes, tussock grasses, and cushion plants) occur in tropical alpine ecosystems around the globe (Smith and Cleef 1988, Luteyn 1992, Hofstede et al. 2003. ...
Overview of the ecology, biodiversity and conservation of the Paramo ecosystem in the highlands of Costa Rica
... According to Smith and Cleef (1988), the flora above the tree line in tropical mountains is mostly of extra-tropical origin. Subularia and Sagina are of holarctic origin (northern temperate geoelements sensu Hedberg 1986). ...
... It exhibits a wide range of life forms and ecological preferences, and is distributed across all major biomes with its primary centers of diversity in southern Africa and South America (Pelser et al. 2007, Nordenstam et al. 2009). The genus is particularly rich in species and endemics along the highlands of the northern Andes (Smith & Cleef 1988, Sklenář et al. 2011, which are known as the páramo (Cuatrecasas 1968). A new delimitation of the genus based on molecular data (Pelser et al. 2007) includes the Andean genera Lasiocephalus Willdenow ex Schlechtendal (1818: 308), Aetheolaena Cassini (1827: 453), and Culcitium Bonpland in Humboldt & Bonpland (1808: 1). ...
Senecio sangayensis, a putative endemic species from the eastern Ecuadorian Cordillera, is described as a new species. It is chiefly distinguished by its habit, striking racemiform synflorescence composed of dense cymose-corymbs subtended by triangular-ovate bracts, and life-history strategy. This new species is known from the páramo of the Sangay National Park. Its IUCN conservation status is preliminarily assessed as Endangered (EN).
Rock outcrops are unique habitats in terms of their geological and ecological specializations, soil availability, water season-ality, and environmental extremes. These habitats have attracted the attention of many researchers worldwide in the last few decades. Indian rock outcrops spread throughout the country with more concentration in the Western Ghats region, supporting many endemic and unique habitat specialist species. Despite Indian outcrops having become hotspots for novel species discoveries in recent times, ecological studies on them are still in their infancy. In the present review, we discuss studies, research gaps, and the scope for future investigations on Indian outcrops. We also compare outcrop studies across the world with the Indian systems in order to understand their uniqueness and peculiarities. Literature and observations revealed the presence of 390 taxa on rock outcrops of the Western Ghats with various adaptive traits such as desiccation tolerance, suc-culence, carnivory, and geophytism, a trend common to most of the tropical outcrops. The dominance of Poaceae endemics, large extents of monocotyledonous mats, and underrepresentation of succulence are unique features of Indian rock outcrops. In the light of various disturbances, faced by Indian outcrops, further studies that would lay a foundation on which conservation strategies can be formulated are want of time.
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.
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.
New fossil remains were found in Neogene and quaternary sedimentary sequences exposed in Alpa Corral and río San Bartolomé localities (Rio Cuarto Department, Córdoba, Argentina). They were assigned to Nopachtus cabrerai (Xenarthra, Cingulata, Glyptodontidae), Notiomastodon platensis (Proboscidea, Gomphotheriidae) and cf. Trigodon gaudryi (Notoungulata, Toxodontidae), and traces of the Scoyenia ichnofacies, as Taenidium barretti, were identified. Based on these findings, we conclude that: 1, the species Nopachtus cabrerai and cf. Trigodon gaudryi are registered for the first time in the Sierras Pampeanas region and support (along with the rest of the known taxa) a clear faunistic similarity to the Pampean region; 2, the beginning of the Neogene sedimentation in the Alpa Corral area (Las Barrancas river and San Bartolome river) would have started during the early Pliocene (Montehermosan Age); 3, the paleoenvironment would have been a fluvial system, with meandering canals interspersed with paleosols developed in floodplains with overflow deposits or abandoned meanders; 4, the paleontological and sedimentary record suggests a well-marked diachronism (from west-southwest to east-northeast) between the beginning of the Neogene sedimentation in the southern sector of San Alberto valley (late Miocene [Huayquerian Age]), the Alpa Corral region (early Pliocene [Monthermosan Age), and Río La Cruz valley (late Pliocene [Chapadmalalan Age]).
Montane ecosystems around the world are found from the equator to the poles and occupy approximately one fifth of the surface of continents and islands (Ives et al. 1997). In South America, the Andes, as the longest ridge in America, extends over approximately 1.5 million km², running from 11° N to 23° S, with altitudes up to 6000 masl. The tropical part runs mainly from Venezuela through Colombia, Ecuador, and Peru, comprising area of approximately 35,824 km² (Cuesta et al. 2009). Main ecosystems in these environments are the glaciers, páramos, and montane forests, including cloud forests; however, montane forests cover most of the region, whereas páramos are insular formations around the highest peaks (Smith and Cleef 1988).
The Archaeological Complex and Stone Forest named Shamana, located in Shulgón locality, Salpo district, Otuzco province, La Libertad region, Peru is made up of various remains of pre-Hispanic stone-edged constructions, including housing, spaces like squares, terraces, access control and protection walls, among other elements that chronologically relate to the Early Intermediate and Late Intermediate periods. Also, to the east, there are the Frailones or Frailes that constitute the stone forest where we can observe various stone or litomorphic forms. It is said that ancient Peruvians learned to live with nature and that different species of plants and animals were used in different aspects of their daily lives. The archaeological reconnaissance was made by surface observations. The existing plant communities in the area were determined, indicating their biotypes and floristic and faunal components. The biological study was based on botanical collections and direct field observations of both flora and fauna, made in ten visits to Shamana with irregular periodicity in 2018. The following plant communities were defined: A) Scrublands, B) Rocks and stony areas. In flora there were registered 120 species, 101 genera and 40 families; distributed in five species of ferns, one species of gymnosperm (Ephedra americana), and the rest angiosperms. There were 19 endemic species, the majority being of Least Concern (LC). In fauna, two endemics species of reptiles (Stenocercus latebrosus and S. melanopygus), 42 species of birds and one species of mammal (Lagidium viscacia) were recorded, all categorized as of Minor Concern (LC). Two species of birds are endemic: Metallura phoebe and Leptasthenura pileata.
Premise:
At the intersection of ecology and evolutionary biology, community phylogenetics can provide insights into overarching biodiversity patterns, particularly in remote and understudied ecosystems. To understand community assembly of the high alpine flora in the Sawtooth National Forest, USA, we analyzed phylogenetic structure within and between nine summit communities.
Methods:
We used high-throughput sequencing to supplement existing data and infer a nearly completely sampled community phylogeny of the alpine vascular flora. We calculated mean nearest taxon distance (MNTD) and mean pairwise distance (MPD) to quantify phylogenetic divergence within summits, and assessed whether maximum elevation explains phylogenetic structure. To evaluate similarities between summits, we quantified phylogenetic turnover, taking into consideration microhabitats (talus vs. meadows).
Results:
We found different patterns of community phylogenetic structure within the six most species-rich orders, but across all vascular plants phylogenetic structure was largely not different from random. There was a significant negative correlation between elevation and tree-wide phylogenetic diversity (MPD) within summits: overdispersion degraded as elevation increased. Between summits, we found high phylogenetic turnover driven by greater niche heterogeneity on summits with alpine meadows.
Conclusions:
Our results provide further evidence that stochastic processes may also play an important role in the assembly of vascular plant communities in high alpine habitats at regional scales. However, order-specific patterns suggest that adaptations are still important for assembly of specific sectors of the plant tree of life. Further studies quantifying functional diversity will be important in disentangling the interplay of eco-evolutionary processes that likely shape broad community phylogenetic patterns in extreme environments.
PREMISE OF THE STUDY: At the intersection of ecology and evolutionary biology, community phylogenetics can provide insights into overarching biodiversity patterns, particularly in remote and understudied ecosystems. To understand community assembly of the high-alpine flora of the Sawtooth National Forest, USA, we analyzed phylogenetic structure within and between nine summit communities.
METHODS: We used high-throughput sequencing to supplement existing data and infer a nearly completely sampled community phylogeny of the alpine vascular flora. We calculated mean nearest taxon distance (MNTD) and mean pairwise distance (MPD) to quantify phylogenetic divergence within summits, and assed how maximum elevation explains phylogenetic structure. To evaluate similarities between summits we quantified phylogenetic turnover, taking into consideration micro-habitats (talus vs. meadows).
KEY RESULTS: We found different patterns of community phylogenetic structure within the six most species-rich orders, but across all vascular plants phylogenetic structure was largely no different from random. There was a significant negative correlation between elevation and tree-wide phylogenetic diversity (MPD) within summits: significant overdispersion degraded as elevation increased. Between summits we found high phylogenetic turnover, which was driven by greater niche heterogeneity on summits with alpine meadows.
CONCLUSIONS: This study provides further evidence that stochastic processes shape the assembly of vascular plant communities in the high-alpine at regional scales. However, order-specific patterns suggest adaptations may be important for assembly of specific sectors of the plant tree of life. Further studies quantifying functional diversity will be important to disentangle the interplay of eco-evolutionary processes that likely shape broad community phylogenetic patterns in extreme environments.
The páramo ecosystem has the highest rate of diversification across plant lineages on earth, of which the genus Espeletia (Asteraceae) is a prime example. The current distribution and molecular phylogeny of Espeletia suggest the influence of Andean geography and past climatic fluctuations on the diversification of this genus. However, molecular markers have failed to reveal subtle biogeographical trends in Espeletia diversification, and metabolomic evidence for allopatric segregation in plants has never been reported. Here, we present for the first time a metabolomics approach based on liquid chromatography-mass spectrometry for revealing subtle biogeographical trends in Espeletia diversification. We demonstrate that Espeletia lineages can be distinguished by means of different metabolic fingerprints correlated to the country of origin on a global scale and to the páramo massif on a regional scale. Distinctive patterns in the accumulation of secondary metabolites according to the main diversification centers of Espeletia are also identified and a comprehensive phytochemical characterization is reported. These findings demonstrate that a variation in the metabolic fingerprints of Espeletia lineages followed the biogeography of this genus, suggesting that our untargeted metabolomics approach can be potentially used as a model to understand the biogeographic history of additional plant groups in the páramo ecosystem
p>Se decribe la flora y la vegetación de pasiajes basálticos de la Sierra de Los Cóndores, Córdoba, Argentina. La vegetación se estudió según criterios de la escuela de Braun-Blanquet; la matriz de 98 inventarios × 272 spp. fue clasificada a través del método ISOPAM. El análisis discrimina tres comunidades correspondientes respectivamente a las tres geoformas relevadas en estos paisajes: Islas rocosas (inselbergs), la Matriz Natural que rodea a las Islas y la Matriz Agrícola que circunda al complejo de paisajes basálticos. Las tres comunidades difieren en su composición florística: las Islas rocosas son los sitios menos perturbados, más ricos en especies, con mayor diversidad, mayor número de especies endémicas y su fisonomía está dominada por formas arbustivas. En el otro extremo, la Matriz Agrícola es la más pobre en especies, la de menor diversidad y endemicidad, y predominan las hierbas perennes y anuales. Las Islas rocosas y la Matriz Natural registran bajos números de especies exóticas en su composición, mientras cerca del 50% de la flora de la matriz agrícola se compone de especies adventicias. Los resultados de este estudio revelan la importancia de las islas rocosas basálticas para la
conservación del patrimonio natural de la provincia de Córdoba.</p
Heterogenity of the vegetation of basaltic environments in central Argentina. The flora and the vegetation of basaltic outcrops of Los Cóndores Mountains, central Argentina, are described. Plant communities were sampled following the Braun-Blanquet methods. The 98 relevés * 272 species matrix was classified through the ISOPAM method. The classification discriminated three main communities occurring in the three different substrates explored in this landscape: Rocky Islands (inselbergs), a Natural Matrix surrounding the Islands and an Agricultural Matrix, surrounding the whole basaltic area. The three communities differed in composition and physiognomy: the Islands were the less disturbed sites, reporting the highest plant species richness and diversity as well as the higher number of endemics, and the lowest number of exotic species. In the other extreme of the disturbance gradient, the Agricultural Matrix showed the opposite patterns and is dominated by annual and perennial herbs, mainly weeds. While the number of aliens is low in the Islands and in the Natural Matrix, almost 50% of the species are exotic in the Agricultural Matrix. The results of this study reveal that the basaltic inselbergs are relevant sites for the conservation of the natural heritage.
The genus Delphinium (Ranunculaceae) consists of ca. 300 species and has a mainly holarctic distribution. Few species have been described from high-altitude areas in West and East Tropical Africa, where the environmental conditions are mostly temperate-like. We aim to clarify the taxonomy of these afro-montane Delphinium species and to understand their evolutionary history in terms of their floral morphology and their phylogenetic and biogeographic relationships. Based on herbarium specimens, we analyze flower shape variation, map the geographic distribution of the morphologically defined taxa and reconstruct the molecular phylogeny of the group. Our quantitative analyses of flower shapes indicate that three species can be defined based on floral morphological traits, hence confirming the latest taxonomic treatment of the group where D. dasycaulon, D. leroyi and D. macrocentrum were described. The examination of herbarium specimens indicates that these three species are almost parapatric. However, their respective monophyly is not supported by molecular data. Considering their relatively young age, the non-monophyly of each of the three morphospecies could be due to incomplete lineage sorting and/or hybridization events. Alternatively, the transition to the D. leroyi floral morph could be the result of evolutionary convergence in the two main groups of afro-montane Delphinium driven by similar pollinators in different sky islands of the East African Rift System. We hypothesize that the main branches of the East African Rift System, as physical barriers to dispersal, may have prevented genetic exchange among geographic clusters.
Premise of the study:
Floras of continental habitat islands, like those of islands, originate mostly through colonization, which can be followed by in situ speciation. We here address the question of the relative importance of colonization and in situ diversification in the high-altitude areas of the eastern African high mountains, the tropical Afroalpine Region, using the most species-rich genus in the region, Senecio, as an example.
Methods:
We expanded earlier Senecioneae phylogenies by adding more tropical African species and analyzed our phylogenetic tree biogeographically.
Key results:
Senecio contains at least five clades with tropical African species, all of them containing tropical afroalpine species. Between four to 14 independent colonization events into the tropical Afroalpine most likely from montane regions in southern Africa were found. Additionally, relationships of tropical afroalpine species to Palearctic and South American taxa were identified. Although some in situ diversification occurred in Senecio in the tropical Afroalpine, the resulting number of species per clade is never higher than seven.
Conclusion:
Like other genera, Senecio colonized the tropical Afroalpine several times independently. Comparison with Mt. Kinabalu, a small tropical alpine-like region in Southeast Asia, and alpine-like regions in the Andes implies that rates of in situ speciation might be linked to area size.
Composition and origins of the world's tropicalpine floras CLEEF* Department of Geography and Planning The Netherlands ABSTRACT. The generic composition of ten tropicalpine floras was
- J M B Smith
Composition and origins of the world's tropicalpine floras J. M. B. SMITH and A. M. CLEEF* Department of Geography and Planning, University of New England, Armidale, N.S.W. 2351, Australia, and *Hugo de Vries-Laboratorium, Universiteit der Amsterdam, Kruislaan 318, 1098 SM, Amsterdam, The Netherlands ABSTRACT. The generic composition of ten tropicalpine floras was