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Where are the glacial refugia in Europe? Evidence from Pteridophytes
Abstract
In this paper we demonstrate that, by investigating polyploid complexes inAsplenium, it is possible to locate the areas in Europe that are southern glacial refugia, and are likely to have been so since the beginning of the Pleistocene during the consecutive cold and warm periods in Europe. Identification and conservation of these specific areas that serve as safe havens for plants, and perhaps animals, is of paramount importance for the maintenance of European biodiversity because Man's activities are resulting in an ever-increasing loss of natural habitats and putting diversity at risk. The genusAspleniumin Europe comprises some 50 taxa: half of these are diploid while the other half are polyploids derived from the diploids. All aspleniums in Europe are (small) rock ferns with high substrate specificity. Today, most of mainland Europe, Scandinavia and the British Isles has been colonized by polyploidAspleniumspecies, while the diploids that gave rise to these polyploids are distributed around (and more or less confined to) the Mediterranean Basin. In the tetraploids genetic variation is partitioned mostly between sites, whereas diploids show a high degree of genetic variation both within and between sites. The tetraploid taxa seem capable of single spore colonization via intragametophytic selfing, but the diploid taxa appear to be predominantly outbreeding. For most diploids at least two gametophytes, produced by different spores, have to be present to achieve fertilization and subsequent sporophyte formation for the successful colonization of a new site. This results in a slower rate of colonization. The formation of auto- and allopolyploid taxa from diploid communities appears to have been a recurrent and common feature in Europe. Minority cytotype exclusion is likely to prevent the establishment of tetraploids within the diploid communities, but spores from tetraploids can establish populations outside the diploid communities. The differences between colonization abilities of tetraploid and ancestral diploid taxa, resulting from their different breeding systems, has prevented the merging and mingling of their ranges and led to the establishment of contact/hybrid zones. This has resulted in the restriction of diploid populations to ancient glacial refugia and the colonization of the rest of Europe by polyploids. Mapping the current distribution of these diploid communities and comparing the genetic diversity within and between outbreeding diploidAspleniumtaxa allows us to define the area, age and historical biogeography of these refugia and to assess their importance for present day genetic and species diversity in Europe.
... Studies discussing the present European pattern of genetic variability and diversity advised South-North postglacial colonization routes for the species (Grivet andPetit 2003, Schmitt 2007). Likewise, the European members of the cosmopolitan Asplenium genus proved to exhibit this postglacial phylogeographic pattern (Viane 1993, Vogel et al. 1999b). The xerophytic small rock fern, Asplenium ceterach ssp. ...
... javorkeanum, the diploid cytotype of the polyploid complex (Vida 1965). During the Pleistocene, multiple parallel polyploidisation occurred in the fragmented refugial diploid populations from where the range expansion of the polyploid populations set out (Vogel et al. 1999b, Soltis and Soltis 1999). The geographical distribution of the two subspecies overlaps, since their habitat requirements and substrate specificity are the same. ...
... The presence of two chloroplast haplotypes in the tetraploids, that are widespread across Europe, infer that the polyploid postglacial colonization occured from at least two independent sources (Trewick et al. 2002). The ability of single spore colonization increases the effectiveness of habitat invasion (Vogel et al. 1999b). The number of colonization steps (founder spores, non-endemic on St. George Hill, located at random positions) is crucial for the genetic variability of a new population The surveyed tetraploid population on St. George Hill is described to possess only TR haplotype. ...
We studied the intrapopulational genetic structure of a small rock fern subspecies Asplenium ceterach ssp. ceterach living in a fragmented habitat. The level and distribution of genetic variation are primarily affected by the colonization events, the reproductive properties of the species, and the short-distance (leptokurtic) dispersal of spores. These biological processes are at the same time strongly influenced by the geomorphological heterogeneity of the habitat. The individuals' genetic variation was detected as multilocus RAPD profile. The spatially constrained portion of genetic variance within subpopulations was studied by means of variograms, i.e., the average genetic dissimilarity between the pairs of organisms against the separation distance. The range of reduced dissimilarity was 11-13 m. Mantel test proved that subpopulations are isolated by distance. The connected local population patches may create a metapopulation structure. This study also surveyed the adequacy of RAPD products to detect the low level of genetic variation of a polyploid plant population.
... Higher ploidy level implies better colonization ability, because species of higher ploidy level have fixed heterozygosity. Fixed heterozygosity reduces the negative consequences of inbreeding depression (Lande and Schemske, 1985) resulting in greater selfing ability (e.g.Flinn, 2006;Masuyama and Watano,1990;Suter et al., 2000;Vogel et al., 1999). As a result, species with higher ploidy level are, in contrast to the diploid species, capable of single spore colonization of a habitat (Trewick et al., 2002;Vogel et al., 1999). ...
... Fixed heterozygosity reduces the negative consequences of inbreeding depression (Lande and Schemske, 1985) resulting in greater selfing ability (e.g.Flinn, 2006;Masuyama and Watano,1990;Suter et al., 2000;Vogel et al., 1999). As a result, species with higher ploidy level are, in contrast to the diploid species, capable of single spore colonization of a habitat (Trewick et al., 2002;Vogel et al., 1999). Thus, we predict that tetraploid A. adulterinum should be a better colonist than diploid A. cuneifolium (Hejný and Slavík, 1980;Vogel et al., 1999) and should consequently show a lower degree of dispersal limitation. ...
... As a result, species with higher ploidy level are, in contrast to the diploid species, capable of single spore colonization of a habitat (Trewick et al., 2002;Vogel et al., 1999). Thus, we predict that tetraploid A. adulterinum should be a better colonist than diploid A. cuneifolium (Hejný and Slavík, 1980;Vogel et al., 1999) and should consequently show a lower degree of dispersal limitation. Both of the studied species are considered as endangered; A. adulterinum is even listed in NATURA 2000, i.e. it is among the species highly protected in Europe (web1). ...
Species distribution in the landscape is limited either by 1. diaspore production, dispersal and establishment abilities or 2. by availability of suitable habitats; 3. or by a combination of both factors. The relative importance of these factors is species-dependent and has mainly been studied for seed plants. We studied the importance of habitat and dispersal limitation for distribution of two rare fern species, Asplenium adulterinum and Asplenium cuneifolium, restricted to serpentine rocks, using analysis of their distribution on a regional scale (several kilometers). Within the model region, all 98 serpentine rocks were mapped. We used data on abiotic characteristics and on the presence of all vascular plant species on the rocks to predict which of the rocks were suitable for the two Asplenium species. Suitable habitats were positively defined mainly by the presence of appropriate microhabitats and the height of the highest rock, which represents the size of space with lowered concurrence. Other determinants of habitat suitability differed between species. Neither species occupied all suitable localities, indicating dispersal limitation. Locality isolation significantly affected one of the species but not the other. Overall, the results suggest that both fern species have suitable but unoccupied localities in the region and demonstrates that ferns, similar to seed plants, are limited by their dispersal ability in the landscape.
... Sipliv is reported from Northern Europe. It is a circumpolar taxon growing in tundra and alpine meadows (Blockeel 2006) and is believed to have a chromosome number of 2n = 90 (Sorsa 1962;Valentine and Moore 1993;Blockeel 2006). Furthermore, several other taxa were recently reported from Northern Europe such as H. continentalis Testo, A. Haines & A. V. Gilman (Testo et al. 2016), H. europaea Björk, and H. acicularis Björk (Björk 2020). ...
... They have not been clearly given for any of these taxa mentioned above, except H. selago, which was the only one to have its chromosomes validly counted, but ploidy has not been reported. In contrast to this condition, in the several European floras (Valentine and Moore 1993;Blockeel 2006) a lower chromosome count was assumed for H. arctica (2n = 90) and a higher chromosome count for H. selago (2n = 264), but it is not supported by primary data. Although the cytotype variation we found may theoretically be related to different numbers of chromosomes, sampling will need to be extended to northern regions (Vejvodová et al. in progress) to determine the actual distribution, morphology and relationships of the various types and their relationship to Huperzia taxa stated in Europe. ...
Polyploidization is pivotal in plant speciation, affecting adaptability, ecological tolerance and specific geographical distribution patterns. While cytotype diversity has been extensively studied in angiosperms and ferns, knowledge in homosporous lycophytes remains very limited. Our study addresses this gap, focusing on the homosporous lycophyte Huperzia selago in Central Europe. The genome size of 1330 individuals from 208 populations were assessed via flow cytometry, revealing five distinct cytotypes (2 x , 3 x , 4 x , 5 x , 6 x ). Challenging chromosome counting using gemmae roots yielded average counts of 140 (2 x ), 204 (3 x ), and 262 (4 x ) chromosomes. The hexaploid genome size (29 pg) approached the upper limits reported for lycophytes. Tetraploids were the most abundant (72.7%), while triploids (21.3%) were less common, while the remaining cytotypes comprised less than 5% of the dataset. Geographical separation of cytotypes was not observed. However, uncommon cytotypes were associated with the Alps and triploids also occured in the highest parts of Western Carpathians. Around 27.3% of populations exhibited multiple cytotypes. Except for atypical diploids, spore abortion differed between even (21.8%) and odd ploidies (65.2%). Microcharacter (stoma, spore) proportions did not linearly correspond with increasing ploidy levels. The high ploidy-level diversity and cytotype coexistence in Central European H. selago match the well documented patterns in ferns and angiosperms. These findings provide valuable insights into lycophyte polyploidy, underscoring the necessity for broader geographical sampling and application of molecular studies to elucidate phylogenetic relationships and taxonomic classifications within the genus Huperzia .
... In Europe, a lauroid-type flora originated and developed with the herbaceous layer composed mainly of ferns [4][5][6][7][8]. The gradual (sub)tropical climate deterioration during Tertiary, especially from the mid-Miocene onwards, together with Pleistocene glaciations, caused the decline of this flora, which contracted to the south and west of Europe, where the climate remained suitable (e.g., [6,[9][10][11][12]). Moreover, during the Pleistocene glacial maxima, many temperate species not only found refugia at lower latitudes but also persisted in refugia at higher latitudes close to, or even within, the limits of the ice sheets [13,14]. ...
... Our findings suggest the Cantabrian Cornice as a main refugium for V. speciosa during the Pliocene, in addition to the Pleistocene refugium traditionally accepted for ferns and other plants [10,25,31,102,103]. This area harbours an endemic haplotype and the highest haplotype diversity (for ptDNA; Figure 2A,B; Table 1), evidencing long-term occupation [24] and demographic stability ( Figure 4A). ...
Fern phylogeographic studies have mostly focused on the influence of the Pleistocene climate on fern distributions and the prevalence of long-distance dispersal. The effect of pre-Pleisto-cene events on the distributions of fern species is largely unexplored. Here, we elucidate a hypothetical scenario for the evolutionary history of Vandenboschia speciosa, hypothesised to be of Tertiary palaeotropical flora with a peculiar perennial gametophyte. We sequenced 40 populations across the species range in one plastid region and two variants of the nuclear gapCp gene and conducted time-calibrated phylogenetic, phylogeographical, and species distribution modelling analyses. Van-denboschia speciosa is an allopolyploid and had a Tertiary origin. Late Miocene aridification possibly caused the long persistence in independent refugia on the Eurosiberian Atlantic and Mediterranean coasts, with the independent evolution of gene pools resulting in two evolutionary units. The Can-tabrian Cornice, a major refugium, could also be a secondary contact zone during Quaternary glacial cycles. Central European populations resulted from multiple post-glacial, long-distance dispersals. Vandenboschia speciosa reached Macaronesia during the Pliocene-Pleistocene, with a phylogeograph-ical link between the Canary Islands, Madeira, and southern Iberia, and between the Azores and northwestern Europe. Our results support the idea that the geological and climate events of the Late Miocene/Early Pliocene shifted Tertiary fern distribution patterns in Europe.
... Vogel et al. 1999. The importance of parts of southern Europe as refuges reflect that climate changes here have been small relative to the available topographic relief (Vogel et al. 1999), allowing plants to track suitable climatic conditions by migrating across small geographic distances. Secondly, reflecting its refugial importance southern Europe also harbours the majority of restricted-range species as well as most of the genetic diversity within the more widespread species (Vogel et al. 1999, Petit et al. 2003, also cf. ...
... The importance of parts of southern Europe as refuges reflect that climate changes here have been small relative to the available topographic relief (Vogel et al. 1999), allowing plants to track suitable climatic conditions by migrating across small geographic distances. Secondly, reflecting its refugial importance southern Europe also harbours the majority of restricted-range species as well as most of the genetic diversity within the more widespread species (Vogel et al. 1999, Petit et al. 2003, also cf. Bakkenes et al. 2002. ...
... In a European context, these events are expected to have had a considerable influence on current species genetic structure and suspected to play a role in the speciation process (Pirounakis et al. 1998; Santucci et al. 1998). Populations may well have been isolated in refugia for many thousands of years during the most recent glacial period, and then expanded northwards following each climate amelioration (Hewitt 1999; Vogel et al. 1999). It is widely accepted that refugia in the ice age could have been in any of three areas in the southern Europe: Iberia, Italy and the far southeast, suggesting three possible post-glacial colonization routes (Hewitt 1999; Figure 1). ...
... It is widely accepted that refugia in the ice age could have been in any of three areas in the southern Europe: Iberia, Italy and the far southeast, suggesting three possible post-glacial colonization routes (Hewitt 1999; Figure 1). Diversity in post-glacial colonization has been suggested by genetic studies on species from a range of taxonomic groups from plants (Nordal and Jonsell 1998; Vogel et al. 1999; Sinclair et al. 1999) to vertebrates (Taberlet et al. 1998; Jaarola et al. 1999; Nesbø et al. 1999). Both idiosyncratic and concordant phylogeographic patterns across genes and taxa have been reported and each has relevance for conservation efforts (Avise 2000). ...
We argue that insect species conservation at large scales should take account of the distribution of genetic diversity among populations. Maintenance of genetic diversity may be vital in retaining a species'' adaptive capacity and evolutionary potential. We illustrate the concept using the example of the large copper butterfly Lycaena dispar in Europe. This species has become extinct in parts of its range and is declining rapidly in others, whilst conversely, increasing in many areas. The latter has recently reduced its conservation status. Mitochondrial DNA analysis is used to construct a phylogeography from a preliminary sample set obtained from across Europe. A cytochrome b fragment of 402 base pairs was sequenced and 10 haplotypes were found. Relatedness among populations suggest that those from northern and central Europe are closely related and probably form one evolutionary significant unit (ESU) reflecting post-glacial colonization from southeast Europe. In contrast, the sample from Italy is divergent and should be considered a separate ESU. Our results, combined with ecological data, suggest that conservation action for this species should be targeted on specific regions and populations.
... Vogel et al. 1999. The importance of parts of southern Europe as refuges reflect that climate changes here have been small relative to the available topographic relief (Vogel et al. 1999), allowing plants to track suitable climatic conditions by migrating across small geographic distances. Secondly, reflecting its refugial importance southern Europe also harbours the majority of restricted-range species as well as most of the genetic diversity within the more widespread species (Vogel et al. 1999, Petit et al. 2003, also cf. ...
... The importance of parts of southern Europe as refuges reflect that climate changes here have been small relative to the available topographic relief (Vogel et al. 1999), allowing plants to track suitable climatic conditions by migrating across small geographic distances. Secondly, reflecting its refugial importance southern Europe also harbours the majority of restricted-range species as well as most of the genetic diversity within the more widespread species (Vogel et al. 1999, Petit et al. 2003, also cf. Bakkenes et al. 2002. ...
The aim of this study is to evaluate the possible consequences of climate change on a representative sample of forest herbs in Europe. A fuzzy climatic envelope was used to predict the location of suitable climatic conditions under two climatic change scenarios. Expected consequences in terms of lost and gained range size and shift in distribution for 26 forest herbs were estimated. These results were combined in an Index of Predicted Range Change for each species. Finally, the effects of habitat fragmentation for potential dispersal routes were evaluated and options for management on a European scale are discussed.
Generally, a good agreement of the estimated suitability under the present climate and the observed current distribution was observed. However, species vary a lot in the degree to which they occupy the presently climatically suitable areas in Europe. Many species are absent from large areas with suitable climate and thus could be said to have poor range‐filling capacity.
A general change in location (range centroid) of the total suitable area was observed: The total suitable area will on average move strongly northwards and moderately eastwards under the relatively mild B1 scenario and more strongly so under the A2 scenario. The required average minimum migration rate per year to track the potential range shift is 2.1 km under the B1 scenario and 3.9 km under the A2 scenario.
Moderate losses in the total suitable area in Europe are predicted for most species under both scenarios. However, the predicted changes are very variable, with one species ( Actaea erythrocarpa ) experiencing total range elimination in Europe (A2 scenario) while the total suitable area is predicted to show large increases for other species. The species that are predicted to experience the greatest proportional losses in their climatically suitable area within their presently realised range tend to have northern or eastern range centroids.
The Index of Predicted Range Change roughly divides the species studied in four groups: One species face a high risk of extinction; eight species are expected to experience moderate to severe threat of extinction; 11 species are not considered at risk and, finally, six species may actually benefit from global warming.
An analysis of potential migration routes shows the importance of maintaining and, if possible, improving the network of forest throughout Europe to make migration possible. It is also suggested to closely monitor the status of boreal and subalpine species that are most threatened by global warming. Finally it is recommended that special concern should be given to increased protection and restoration of forest habitats in southern montane areas for their crucial long‐term importance for the maintenance of European plant diversity.
... 11,000 species; [1]), there is a comparative lack of data on population genetics and phylogeography for this important group [2]. Numerous ferns are considered lineages of Tertiary origin, especially those from the Mediterranean region [3,4], which constituted the main component of the herbaceous layer of the European lauroid forest [5][6][7] and survived the Quaternary glaciations in well-characterized glacial refugia, such as the Iberian Peninsula, Italy, the Balkans, and Greece [8]. The evolutionary history of C. macrocarpa remains unknown. ...
The tree fern Culcita macrocarpa, a threatened Iberian–Macaronesian endemism, represents the sole European species of the order Cyatheales. Considered a Tertiary relict of European Palaeotropical flora, its evolutionary history and genetic diversity, potentially influenced by presumed high clonal propagation, remain largely unknown. This study elucidates the phylogeographic history of C. macrocarpa, assessing the impact of vegetative reproduction on population dynamics and genetic variability. We provide genetic data from eight newly identified nuclear microsatellite loci and one plastid DNA region for 17 populations spanning the species’ range, together with species distribution modeling data. Microsatellites reveal pervasive clonality in C. macrocarpa, which has varied among populations. We assess the impact of clonality on genetic diversity and evaluate how estimates of intra-population genetic diversity indices and genetic structuring are affected by the chosen definition of “individual” (focusing exclusively on genetically distinct individuals, genets, as opposed to considering all independent clonal replicates, ramets). We identify two main population groups, one in the northern Iberian Peninsula and the other in the Macaronesian archipelagos and southern Iberian Peninsula. Within each group, we found relict populations (in the Azores and the Cantabrian Cornice) as well as recent originated populations. This population structure suggests colonization dynamics in which recent populations originated from one or a few genets of relict populations and became established through intra-gametophytic self-fertilization and vegetative expansion. DAPC analysis facilitated the identification of alleles that most significantly contributed to the observed population structure. The current Andalusian populations appear to have originated from colonization events from the Azores and the Cantabrian Cornice. Our findings suggest that C. macrocarpa persisted through the Last Glacial Maximum in two refugia: the Azores and the Cantabrian Cornice. Colonization into new areas occurred presumably from these refuges, generating two large population groups with structured genetic diversity. This study underscores the significance of clonality in establishing new populations and shaping genetic structure.
... Both hypotheses are supported by the fact that diploids have only been found in Central Europe at one small site in the central Alps. We could speculate that the diploids survived in very limited population number whereas tetraploids were more successful and became widespread after last glacial maximum, as in some examples of ferns(Vogel et al. 1999).Distinguishing of cytotypes via spores and stomataIn ferns, the spore and stoma size are usually correlated with ploidy level(Ekrt et al. 2021). In angiosperms a similar trend is known with pollen and stomata (e.g.,McGoey et al. 2014). ...
Polyploidization is pivotal in plant speciation, enhancing adaptability, ecological tolerance and specific geographical distribution pattern. While cytotype diversity is extensively studied in angiosperms and ferns, knowledge in homosporous lycophytes remains very limited. This study addresses this gap, focusing on the homosporous lycophyte Huperzia selago in Central Europe. Employing flow cytometry, we assessed genome size in 1330 H. selago individuals from 208 populations identifying five distinctive cytotypes (2 x , 3 x , 4 x , 5 x , 6 x ). Challenging chromosome counting on somatic gemmae roots was applied for the three lowest cytotypes yielded average counts of 140, 204, and 262 chromosomes, respectively. Geographical separation of cytotypes was not observed. Tetraploids were most widespread (72.7%), while triploids (21.3%) were rare, and extremely rare are cytotypes 2 x , 5 x , 6x constituted less than 5% of the dataset. Uncommon cytotypes were associated with the Alps and triploids occurs also in the highest parts of Western Carpathians. Hexaploid genome size (29 pg) approached upper limits reported in lycophytes. Around 27.3% of populations exhibited mixed cytotypes. Except for atypical diploids, spore abortion differed between even and odd ploidies, approximately 21.8% and 65.2%, respectively. Microcharacter sizes (stoma, spore) did not linearly correspond with increasing ploidy levels. The high ploidy-level diversity and cytotype coexistence in Central European Huperzia selago match the well documented patterns in ferns and angiosperms. These findings provide valuable insights into lycophyte polyploidy, underscoring the necessity for broader geographical sampling and applicance of molecular studies to elucidate phylogenetic relationships and taxonomic classifications within the genus Huperzia .
... Numerous ferns are considered lineages of Tertiary origin, especially most of the Mediterranean region [16,17], which were the main component of the herbaceous layer of the European lauroid forest [18][19][20]. The climate deterioration during the Tertiary, especially from the mid-Miocene onwards, together with Pleistocene glaciations, caused the decline of this flora, whose representatives survived in refugia present along the European Atlantic coast and Macaronesia [15,[21][22][23][24][25][26]. The hypothesis of relictualism has been tested recently for 18 representative angiosperms of the Macaronesian laurel forest, using fossil data, ancestral area reconstruction, and molecular dating [27]. ...
Macaronesia has been considered a refuge region of the formerly widespread subtropical lauroid flora that lived in Southern Europe during the Tertiary. The study of relict angiosperms has shown that Macaronesian relict taxa preserve genetic variation and revealed general patterns of colonization and dispersal. However, information on the conservation of genetic diversity and range dynamics rapidly diminishes when referring to pteridophytes, despite their dominance of the herbaceous stratum in the European tropical palaeoflora. Here we aim to elucidate the pattern of genetic diversity and phylogeography of Diplazium caudatum, a hypothesized species of the Tertiary Palaeotropical flora and currently with its populations restricted across Macaronesia and disjunctly in the Sierras de Algeciras (Andalusia, southern Iberian Peninsula). We analysed 12 populations across the species range using eight microsatellite loci, sequences of a region of plastid DNA, and carry out species-distribution modelling analyses. Our dating results confirm the Tertiary origin of this species. The Macaronesian archipelagos served as a refuge during at least the Quaternary glacial cycles, where populations of D. caudatum preserved higher levels of genetic variation than mainland populations. Our data suggest the disappearance of the species in the continent and the subsequent recolonization from Macaronesia. The results of the AMOVA analysis and the indices of clonal diversity and linkage disequilibrium suggest that D. caudatum is a species in which inter-gametophytic outcrossing predominates, and that in the Andalusian populations there was a shift in mating system toward increased inbreeding and/or clonality. The model that best explains the genetic diversity distribution pattern observed in Macaronesia is, the initial and recurrent colonization between islands and archipelagos and the relatively recent diversification of restricted area lineages, probably due to the decrease of favorable habitats and competition with lineages previously established. This study extends to ferns the concept of Macaronesia archipelagos as refugia for genetic variation.
... In Russia, Dmitry Litvinov (1890Litvinov ( , 1902 applied the concept of glacial refugia for the explanation of the presence of the southern steppe and limestone floras over riverbanks, which were studied by several renown botanists including the author of the symbiogenesis concept of evolution Boris Kozo-Polyansky (Agafonov et al., 2021). Several recent works established the trends of migration of species that support the glacial refugia patterns in different systematic groups (Hewitt, 1999;Vogel et al., 1999;Kyrkjeeide et al., 2014;Roberts and Hamann, 2015), while other works challenge the view that, during glacial maxima, organisms migrated south out of their ranges to search favourable climates (Rowe et al., 2004). It is now quite evident that there was a large variation in both the size of refugia and the duration during which species are confined to them which resulted in high variability concerning the evolution of refugia species and their genetic diversity (Stewart et al., 2010). ...
Valery Taliev (1872–1932) was one of the first natural scientists who investigated the importance of anthropogenic factors in the evolution and geographic distribution of higher plants. He outlined major parameters of the origin and spreading of weed plants, of the flora of riverbanks, and proposed a direct role of man in changing the balance between forests and steppes. In his evolutionary views, Taliev emphasized the significance of parallel series of changes and of the directed evolution in several groups of higher plants as well as of geographic heterogeneity of plant species.
... Studies on rock-dwelling populations of rock ferns (Schneller & Holderegger 1996, Vogel et al. 1999, Suter et al. 2000 attributed their population structure to multiple events of single-spore colonization via intra-gametophytic selfing, promoted by its long-distance dispersion capacity (Perrie & Brownsey 2007, De Groot et al. 2012, Bauret et al. 2017. In this context, the low gene flow registered between populations of angiosperms from different inselbergs (Barbará et al. 2007, Palma-Silva et al. 2011 pointed that each inselberg might host genetically isolated populations (de Paula et al. 2016, Hmeljievski et al. 2017. ...
Serpocaulon demissum is herein proposed as a new combination based on the study of the type specimens and protologue of Goniophlebium demissum, as well as the comparison with its sympatric and morphologically similar species, S. catharinae and S. vacillans, two widespread species from the Atlantic Forest. Serpocaulon demissum is similar to these species by the presence of patent rhizomes scales and pinnatisect laminae, but differs from them by its thick amylaceous rhizomes, larger rhizome scales, and spores without folded perine. This taxon represents an endemic species from the Brazilian inselbergs. A re-description that includes a lectotype designation, line drawings, SEM pictures of the spores, pictures of the plant in the field, information of the novel habitat and rhizome stores, distribution map, and the conservation status of the species is presented.
... Τα δασικά είδη της Ευρώπης έχουν επιβιώσει έντονες κλιματικές αλλαγές στο παρελθόν, μέσα από συνεχείς μετακινήσεις, που άφησαν έντονο το αποτύπωμά τους στη γενετική ποικιλότητα των σημερινών πληθυσμών (Papageorgiou et al. 2014).(Grivet & Petit 2002, Ferris et al. 1999), ενώ η πλειοψηφία της ποικιλότητας θα παρέμενε στο φυσικό περιβάλλον του καταφυγίου (Vogel et al. 1999).Tsiripidis & Athanassiadis 2003). Κατά την τελευταία παγετώδη περίοδο, η οξιά βρήκε καταφύγιο στο νότο όπως έκαναν και άλλα taxa, αλλά φαίνεται ότι δεν ήταν ικανό να επιβιώσει στα καταφύγια της Ιβηρικής, ως συνέπεια, όλο το δυτικό μέρος της γεωγραφικής κατανομής αποικήθηκε από τα Βαλκάνια (Demesure et al. 1996). ...
Η λεπτή ισορροπία ανάμεσα στην εξερχόμενη και στην εισερχόμενη ηλιακή
ακτινοβολία προσδιορίζει το παγκόσμιο κλίμα. Οποιαδήποτε μεταβολή οδηγεί σε
αλλαγή του κλίματος. Οι βασικότεροι παράγοντες είναι η ηλιακή ακτινοβολία, η
ατμοσφαιρική σύσταση, οι αλλαγές στη χρήση γης. Η συχνότητα ακραίων
φαινομένων οδήγησε τους επιστήμονες στη χρήση μοντέλων και δεικτών για την
παρατήρηση των κλιματικών μεταβολών που οφείλονται σε αυξομειώσεις
σημαντικών παραμέτρων.
Σε αυτήν την εργασία θα γίνει αρχικά αναφορά στα σημαντικότερα μαθηματικά
μοντέλα ατμοσφαιρικής ρύπανσης και διασποράς (Gauss, Euler, Αριθμητικά, Φυσικά,
Στατιστικά, Εμπειρικά) και σε δείκτες ποιότητας αέρα. Επιπλέον θα δοθεί ιδιαίτερη
σημασία στη χρησιμότητα των παγκόσμιων και τοπικών κλιματικών μοντέλων ως
εργαλεία προσομοίωσης του κλίματος στα σενάρια κλιματικής αλλαγής καθώς και
στις σημαντικότερες αλλαγές που θα προκύψουν στην Ελλάδα έως το 2100 από την
εφαρμογή των μοντέλων αυτών στη δημόσια υγεία. Ένα άλλο σημαντικό μέρος αυτής
της εργασίας αφορά στη χρήση Υπολογιστικής Νοημοσύνης για την διερεύνηση του
προβλήματος. Συγκεκριμένα, θα γίνει σύνδεση των μετεωρολογικών παραμέτρων με
φαινόμενα ατμοσφαιρικής ρύπανσης και με περιόδους έντονης ξηρασίας και
υγρασίας με τη βοήθεια Ασαφών Γνωστικών Χαρτών (Fuzzy Cognitive Maps). Με
αυτό τον τρόπο θα δημιουργηθούν σενάρια που θα υποδηλώνουν τις συσχετίσεις,
θετικές ή αρνητικές, ανάμεσα στις συνδέσεις των παραμέτρων με τα φαινόμενα
ρύπανσης και ξηρασίας.
Στο Τμήμα Δασολογίας και Διαχείρισης Περιβάλλοντος και Φυσικών Πόρων του
Δημοκρίτειου Πανεπιστημίου Θράκης έχει γίνει στο πρόσφατο παρελθόν μια
ερευνητική προσπάθεια με τη Χρήση Συστημάτων Ασαφούς Άλγεβρας-Νόησης και
Γεωγραφικών Συστημάτων Πληροφοριών, για την μοντελοποίηση του προβλήματος
της ξηρασίας στην Κύπρο τα τελευταία 30 έτη (Παπακωνσταντίνου κ.ά. 2010).
Η καινοτομία της έρευνας που παρουσιάζεται σε αυτήν την εργασία είναι η χρήση
Χαρτών Ασαφούς Νόησης (Fuzzy Cognitive Maps) προς το ευρύτερο πρόβλημα της
κλιματικής αλλαγής και των συνεπειών του.
... The members of this clade are lumped together historically under pteridophytes and "fern and fern allies" (Smith et al., 2006). A revised classification for extant ferns bySmith et al. (2006)These ferns emerged from the aquatic environment and later became dominant in the tropical lowland and wetland forests and have been important component of terrestrial vegetation since the Late Devonian (Odland et al., 1995;Vogel et al., 1999;Lehmann et al., 2002;DiMichele and Phillips, 2002). Presently, majority of fern species are often found in tropical regions (Poulsen and Nielsen, 1995). ...
Our natural ecosystems continuously suffer as we gear towards modernization. Anthropogenic activities do not only increase the rate of species extinction but also reduce the planet’s sustainability. However, such activities are inevitable since food production is the utmost priority for man’s survival. Efforts have been made to slow down the Earth’s destruction by discerning ways by which food production is optimized while resource consumption is minimized. Scientists and researchers are trying very hard to understand the eco-physiological importance of all living things particularly those that are seemingly valueless organisms. This project was able to discover possibly novel microorganisms that are found in plants that are often ignored and treated as rubbish and with no apparent economic value.
Root symbiotic fungi isolated from the epiphytic fern, Drynaria quercifolia were found to exhibit growth promoting potentials and drought-stress adaptive mechanisms which are speculated to help their host survive hostile epiphytic habitats. When tested in vitro, these fungal symbionts were found to produce phytohormones and antioxidants. The isolates were also found to perform phosphate solubilisation reduce the production of stress hormone, ethylene. More importantly, these microorganisms significantly improved the agronomic traits of rice even when exposed to drought conditions. With such enticing traits, it can be concluded that the, apparently valueless, epiphytic ferns, Drynaria quercifolia, harbor fungal symbionts with potential agricultural impact. In the advent of climate change that causes apparent aggravation of drought conditions in many parts of the globe, coupled with increased pressure in food production, this project could seems to potentially help the agricultural sector in a sustainable and eco-friendly way.
================================================================================================ HOW TO CITE: Aban, J. L. (2017). Taxonomic diversity, potential growth promoting capacity and ecophysiological drought stress-adaptive mechanisms of root symbiotic fungi (RSF) from Drynaria quercifolia L. and their effects on rice (Oryza sativa L.). Ph.D. Dissertation. Saint Louis University, Baguio City, Philippines. pp 1-59. doi: 10.13140/RG.2.2.14055.65442/2.
... As a continental island, Sardinia would have been further protected by marine buffering of climatic oscillations (Cronk, 1997;Médail & Diadema, 2009). There is evidence that it served as a glacial refugium for temperate species (Médail & Diadema, 2009;Vogel, Rumsey, Schneller, Barrett, & Gibby, 1999). However, even within refugia, it is likely that glacial oscillations influenced species distribution and fragmentation by a differential effect on environmental niches and habitats (Cimmaruta, Lucente, & Nascetti, 2015;Gómez & Lunt, 2007;Provan & Bennett, 2008). ...
The identification of historic and contemporary barriers to dispersal is central to the conservation of endangered amphibians, but may be hindered by their complex life history and elusive nature. The complementary information generated by mitochondrial (mtDNA) and microsatellite markers generates a valuable tool in elucidating population structure and the impact of habitat fragmentation. We applied this approach to the study of an endangered montane newt, Euproctus platycephalus. Endemic to the Mediterranean island of Sardinia, it is threatened by anthropogenic activity, disease, and climate change. We have demonstrated a clear hierarchy of structure across genetically divergent and spatially distinct subpopulations. Divergence between three main mountain regions dominated genetic partitioning with both markers. Mitochondrial phylogeography revealed a deep division dating to ca. 1 million years ago (Mya), isolating the northern region, and further differentiation between the central and southern regions ca. 0.5 Mya, suggesting an association with Pleistocene severe glacial oscillations. Our findings are consistent with a model of southward range expansion during glacial periods, with postglacial range retraction to montane habitat and subsequent genetic isolation. Microsatellite markers revealed further strong population structure, demonstrating significant divergence within the central region, and partial differentiation within the south. The northern population showed reduced genetic diversity. Discordance between mitochondrial and microsatellite markers at this scale indicated a further complexity of population structure, in keeping with male-biased dispersal and female philopatry. Our study underscores the need to elucidate cryptic population structure in the ecology and conservation strategies for endangered island-restricted amphibians, especially in the context of disease and climate change.
... The recent distribution of H. pastinacifolia represents only a slightly increased range in the southern part and two fragmented locations in the northern part of that distribution , separated by forest and restricted to steep overhangs (Fig. 6). As many narrow endemics found south of the Alps did not spread after the end of the glaciations and remained within refugia (Vogel et al., 1999 ), this seems to be the case for H. pastinacifolia as well. It can be additionally explained by poor seed dispersal. ...
Hladnikia pastinacifolia Rchb., a narrow endemic, has an extremely restricted distribution in Trnovski gozd (Slovenia), despite the presence of many sites with suitable habitats. We compared the morphological traits of plants from different populations and habitats. The overall pattern showed that the smallest plants, with low fruit number, are found on Caven (locus classicus or type locality); the largest individuals, with high fruit number, grow in the Golobnica gorge. As judged by plant size and seed set, the optimal habitats are screes. We used RAPD markers to estimate genetic variation between and within populations, as well as between and within the northern and the southern parts of the distribution area. Hladnikia showed only a low level of RAPD variability. AMOVA partitioned the majority of genetic diversity within selected populations. The low genetic differentiation between populations and their genetic depauperation indicates survival in situ, since the Trnovski gozd plateau most likely was a nunatak region in the southern Prealps during Pleistocene glaciations. Later range expansion of extant populations was limited by poor seed dispersal. We also analyzed the cpDNA trnL-F intergenic spacer to check whether the sequence is useful for studying the phylogenetic relationships of Hladnikia within the family Apiaceae (Umbelliferae). Our results support the assertion that H. pastinacifolia is an old taxon.
... This phenomenon in these P. coridon populations is most probably the result of their marginal position, especially as genetic impoverishment is commonly observed as a consequence of range expansion (e.g. Highton and Webster 1976;Cwynar and MacDonald 1987;Konnert and Bergmann 1995;Soltis et al. 1997;Bernatchez and Wilson 1998;Vogel et al. 1999;Hundertmark et al. 2002;Hassel et al. 2005;Brito 2007;Taylor and Keller 2007;see Ibrahim et al. (1996) for theoretical background). ...
As a consequence of postglacial range expansion, hybrid zones evolved where different genetic lineages met. In this study, we analysed the Chalk-hill Blue Polyommatus coridon all along the contact zone of two expansive lineages. This zone stretches from the sandy areas of north-eastern Germany, along the mountain ranges of the German-Czech border and throughout the eastern Alps. We studied allozymes (19 loci) of 38 populations (1542 individuals) and compared these data sets against 15 populations of the western and 15 populations of the eastern lineages and found different degrees of hybridization. Thus, the calcareous regions of Thuringia and Sachsen-Anhalt were mostly colonized by the western lineage. The middle mountain ranges between Bavaria and Bohemia represented a strong barrier blocking further expansion and thus completely impeding hybridization in this region. More intense hybridization was detected in the populations of the eastern Alps, especially in the north-eastern part, where the Danube most probably acted as an expansion corridor for both lineages followed by intensive hybridization. In the south-eastern Alps, hybrid populations were mostly detected in the easternmost parts and along the larger river valley of Drava and Mur; pure western populations dominated in the other areas of this region. These results show that the degree of hybridization along a contact zone is correlated with the ecological demands of a species and the regional physical geographic circumstances. This finding was proved for the Chalk-hill Blue in our study but is also the most likely scenario in most animal and plant species.
... The Macaronesian archipelagoes (Azores, Canary Islands and Madeira) are traditionally regarded as outstanding refugia for relict Tertiary lineages (Engler 1879, Axelrod 1975, Bramwell 1976, Sunding 1979, Rodríguez-Sánchez et al. 2009). However, mesic areas within the Mediterranean basin have also enabled long-term survival of some species in several glacial refugia (Vogel et al. 1999, Thompson 2005, Mejías et al. 2007), as have also some Atlantic areas in the Iberian Peninsula (Sunding 1979Sunding , Désamoré et al. 2011). The south-west of the Iberian Peninsula constitutes one of the main glacial refugia for the European fauna and flora (Hewitt 2000). ...
2011: Phylogeographic relationships between the mosses Exsertotheca intermedia from Macaronesian islands and Neck-era baetica from southern glacial refugia of the Iberian Peninsula. — Ann. Bot. Fennici 48: 133–141. The phylogeographic relationships between the Macaronesian islands and southern glacial refugia of the Iberian Peninsula was studied using molecular markers and two mosses as model species: Exsertotheca intermedia from Macaronesia and the recently described Neckera baetica from the Iberian Peninsula. The new combination Exser-totheca baetica (Guerra) Draper, González-Mancebo, O. Werner, J. Patiño & Ros is proposed for the latter. The genus Neckera has recently undergone considerable systematic and taxonomic changes, but our results show that the European species N. cephalonica and N. pumila belong in Neckera s. stricto.
... The rapid migration process itself presumably further supported the development of a short-lived, mobile ''colonizer'' phenotype within the northward advancing populations (Bennett 1986, Brubaker 1986, Clark 1998). In contrast, the geographical distribution of the south Iberian F. alnus probably shifted vertically rather than horizontally during transi-tions between glacial and interglacial periods (Bennett et al. 1991, Vogel et al. 1999), and the absolute distances covered by the migrating populations were much smaller than these covered by their northern conspecifics. Therefore it may be assumed that selection on genet mobility was less pronounced in the Iberian populations while selection on competitive capacity was higher (Hampe and Bairlein 1999b). ...
Many European tree species survived Pleistocene glaciations in Mediterranean refugia and rapidly recolonized temperate Europe afterwards. Inter- and postglacial migration processes are assumed to have catalized evolutionary optimizations of dispersal-related traits, but up to now empirical evidence is lacking in vertebrate-dispersed plants. We investigated if south Iberian glacial relict and central European “colonizer” populations of the bird-dispersed tree Frangula alnus have experienced differentiations of dispersal-related traits which increase the mobility of northern populations. A comparison of lifetime reproductive strategy, disperser guilds, ripening phenology, and fruit design revealed considerable differences. Compared to south Iberian conspecifics, central European plants were considerably smaller and experienced a highly accelerated generation turnover. In south Iberian populations seed dispersal was carried out almost completely by resident birds which occurred in constant abundances throughout the ripening season. In contrast, central European seeds were dispersed by migrants whose abundances changed considerably during the ripening season. Several bird species were involved in both study areas but rendered different importance for seed dispersal. The fruit ripening pattern was highly asynchronous throughout the ripening season in south Iberia, while central European trees showed a complex ripening sequence which resulted in a significant correlation between fruit abundance and changing disperser availability. Central European fruits were smaller and showed a considerably smaller seed load than south Iberian fruits, thus presumably being more attractive for their small-sized main dispersers (Sylvia warblers). Chemical analyses revealed significant differences in contents of water, glucose, fructose, proteins, ash. and phenolic compounds. The extensive differentiation of dispersal-related traits in F. alnus suggests that even weak selective pressures by frugivores may induce evolutionary adjustments of dispersal traits over large time scales. We suggest that the differences we observe today evolved during the species' distribution shifts in the Quaternary.
... It is difficult to establish the specific locations of "refuge" areas, this problem existing for other areas of Europe (Vogel et al. 1999). The coasts have always been suggested because on the Iberian Peninsula these were not affected by the glaciations (Garcia Anton et al. 1990; Costa Tenorio et al. 1997). ...
The Italian and Balkan peninsulas have been places traditionally highlighted as Pleistocene glacial refuges. The Iberian Peninsula,
however, has been a focus of controversy between geobotanists and palaeobotanists as a result of its exclusion from this category
on different occasions. In the current paper, we synthesise geological, molecular, palaeobotanical and geobotanical data that
show the importance of the Iberian Peninsula in the Western Mediterranean as a refugium area. The presence of Aesculus aff. hippocastanum L. at the Iberian site at Cal Guardiola (Tarrasa, Barcelona, NE Spain) in the Lower–Middle Pleistocene transition helps to
consolidate the remarkable role of the Iberian Peninsula in the survival of tertiary species during the Pleistocene. The palaeodistribution
of the genus in Europe highlights a model of area abandonment for a widely-distributed species in the Miocene and Pliocene,
leading to a diminished and fragmentary presence in the Pleistocene and Holocene on the southern Mediterranean peninsulas.
Aesculus fossils are not uncommon within the series of Tertiary taxa. Many appear in the Pliocene and suffer a radical impoverishment
in the Lower–Middle Pleistocene transition. Nonetheless some of these tertiary taxa persisted throughout the Pleistocene and
Holocene up to the present in the Iberian Peninsula. Locating these refuge areas on the Peninsula is not an easy task, although
areas characterised by a sustained level of humidity must have played an predominant role.
... In the case of ferns, altitude range could also reflect the existence of rocky cliffs and inaccessible slopes favouring the establishment of many rupestrian fern species. The importance of Plant Ecol (2008) 198:149–167 163 the maximum-altitude topographic variable reflects the relevance of the role played by mid and higher mountains (above 1.500 m), which acted as refugia throughout Pleistocene climate cycles for northern and central European species (Vogel et al. 1999). As with all vascular flora (Lobo et al. 2001), Pausas and Sáez (2000) found that north-eastern Iberian diversity correlated positively with maximum altitude (i.e. ...
This article delineates the compositional regions present in the Iberian–Balearic fern flora and compares these regions to
previously proposed biogeographic units. It also assesses the extent to which environmental variables could explain the regions
and the fern species richness gradients found within them. A combination of 40 previously published and new maps were used
to compile the distribution of 123 pteridophytes on a 50×50km UTM grid. Cluster analysis of the resulting 257 squares was
used to classify 10 regions based on fern species assemblages. Discriminant function analysis identified the environmental
variables that best explained these fern composition regions. Using generalized linear models; the number of species in each
square was regressed against topography, climate, geology, environmental diversity, land use and spatial variables within
each region. Two main latitudinal pteridophyte zones can be recognized in the Iberian Peninsula. These two zones are longitudinally
subdivided into two sub zones. The 10 regions established significantly differ both in species richness and influential environmental
variables. Climatic variables discriminate the most among regions, followed by topography, heterogeneity and geology. Pteridophyte
richness varies, with richer areas being located along the coast and the main mountain ranges and the poorest areas being
in the central plateaus and some north eastern and south western river basins. Species richness variation in Iberia is positively
correlated with altitude range, precipitation, maximum altitude and area with siliceous soils. It is negatively correlated
with the total annual days of sun, however. The fact that species richness is explained by different variables within each
of the 10 regions indicates that the specific factors determining the spatial distribution of species richness vary from region
to region. Some coastal regions are poorly explained by the model, and display a negative correlation with the selected causal
factors. This finding suggests that persistent historic effects might play a local role in determining species assemblages
in these regions.
... Leaf material was ground in a Tris-HCl (pH 7.5) extraction buffer (Soltis et al. 1983), and proteins were fractionated on 12.5% hydrolyzed potato starch gels under standard procedures (Wendel & Weeden 1989;Vogel et al. 1999). The following enzyme systems where resolved using the lithium borate electrode and gel buffer system 8 ofSoltis et al. (1983) ...
Arabis alpina is a widespread plant of European arctic and alpine environments and belongs to the same family as Arabidopsis thaliana. It grows in all major mountain ranges within the Italian glacial refugia and populations were sampled over a 1300 km transect from Sicily to the Alps. Diversity was studied in nuclear and chloroplast genome markers, combining phylogeographical and population genetic approaches. Alpine populations had significantly lower levels of nuclear genetic variation compared to those in the Italian Peninsula, and this is associated with a pronounced change in within-population inbreeding. Alpine populations were significantly inbred (F(IS) = 0.553), possibly reflecting a change to the self-incompatibility system during leading edge colonization. The Italian Peninsula populations were approaching Hardy-Weinberg equilibrium (outbreeding, F(IS) = 0.076) and genetic variation was highly structured, consistent with independent local 'refugia within refugia' and the fragmentation of an established population by Quaternary climate oscillations. There is very little evidence of genetic exchange between the Alps and the Italian Peninsula main distribution ranges. The Alps functioned as a glacial sink for A. alpina, while the Italian Peninsula remains a distinct and separate long-term refugium. Comparative analysis indicated that inbreeding populations probably recolonized the Alps twice: (i) during a recent postglacial colonization of the western Alps from a Maritime Alps refugium; and (ii) separately into the central Alps from a source outside the sampling range. The pronounced geographical structure and inbreeding discontinuities are significant for the future development of A. alpina as a model species.
Southern European peninsulas have repeatedly played notable roles as refuges in the natural history of flora during periods of glaciation. Euonymus latifolius (Celastraceae) is a relict species from the last Würmian glaciation in the Iberian Peninsula. It still lives with isolated populations in favourable, cool mountainous microhabitats, being an extremely rare, critically endangered species. These Iberian populations are often high-priority targets for conservation due to their long-term persistence and unique evolutionary trajectory. Previously, it has not been feasible to promote significant programmes for reintroduction and/or population reinforcement of this singular plant species due to the great difficulties of conventional propagation. In this study, we analysed the effects of temperature, light and gibberellic acid (GA3) on the germination responses of E. latifolius to develop an effective protocol for seed germination as a main outcome. The results are coherent with the climatic temperature conditions recorded broadly in the Iberian Peninsula in the past and in the current refuge locations for the taxon. The germination responses of E. latifolius are compatible with those of seeds with intermediate physiological dormancy. In particular, the seeds required a 10-week warm period (20/7°C + 15/4°C) followed by 20 weeks of cold period (5 + 1.5°C) to break dormancy and achieve germination values over 90%. GA3 also promoted germination (80%). Therefore, we developed the first effective protocol for promoting E. latifolius seed germination and, thus, sexual propagation, to facilitate urgent ex situ actions in the current climate change context.
Knowledge of relationships between phylogenetic structure of a biological assemblage and ecological factors that drive the variation of phylogenetic structure among regions is crucial for understanding the causes of variation in taxonomic composition and richness among regions, but this knowledge is lacking for the global flora of ferns. Here, we fill this critical knowledge gap.
We divided the globe into 392 geographic units on land, collated species lists of ferns for each geographic unit, and used different phylogenetic metrics (tip‐ vs basal‐weighted) reflecting different evolutionary depths to quantify phylogenetic structure. We then related taxonomic and phylogenetic structure metrics to six climatic variables for ferns as a whole and for two groups of ferns (old clades vs polypods) reflecting different evolutionary histories across the globe and within each continental region.
We found that when old clades and polypods were considered separately, temperature‐related variables explained more variation in these metrics than did precipitation‐related variables in both groups. When analyses were conducted for continental regions separately, this pattern holds in most cases.
Climate extremes have a stronger relationship with phylogenetic structure of ferns than does climate seasonality. Climatic variables explained more variation in phylogenetic structure at deeper evolutionary depths.
Bryophytes generally have broad geographical ranges that suggest high dispersal ability. The aim of this study was to test hypotheses about dispersal limitation, as indicated by isolation by distance, in four spore-producing species of the moss genus Sphagnum (Sphagnum carolinianum, Sphagnum missouricum, Sphagnum macrophyllum and Sphagnum pylaesii) and to assess whether plants in the southern USA harbour high levels of unique alleles and/or other indicators of exceptional genetic diversity. Isolation by distance was detected in all four species, but regional patterns of genetic structure were very species specific. Northern and southern genotype groups were detected in S. carolinianum and S. missouricum, but in S. pylaesii plants from the Adirondack Mountains of New York were genetically distinct from others to the north and south. One species, S. macrophyllum, exhibited differentiation between northern and southern genetic groups that appeared to reflect more ancient phylogenetic diversification.
Ferns and lycophytes are plants with great diversity in tropical and subtropical regions, mainly in rain forests. In Brazil, the biome with the largest number of ferns and lycophytes species is the Atlantic Forest. However, studies on the distribution patterns of these species throughout the biome few and specific some regions. To reduce this knowledge gap, our work investigated the key areas of richness and endemism for species of ferns and lycophytes occurring in the Brazilian Atlantic Forest and assesses the effectiveness of protected areas for protecting this biodiversity. We registered 939 species, distributed among 39 families and 140 genera. We established four regions (centres) with a high number of species designated as: Bahia, Espinhaço/Caparaó, Serras do Mar/Mantiqueira and Southern centres. For endemism, we identified six relevant areas, all within the proposed richness centres. We found that 73.4% of the species occur within protection areas. The percentages of endemic and threatened species occurring within the limits of these areas correspond to 65.5% and 50.66%, respectively. The patterns of richness and endemism are directly related to the topographic and climatic characteristics that make up the environmental heterogeneity of the Brazilian Atlantic Forest.
Asplenium flabellifolium Cav. is a cytologically variable Australian and New Zealand fern. Here, we sequence chloroplast trnL-trnF and rps4-trnS from samples throughout its range to provide the first phylogeographic investigation of a fern common in both countries. Twenty-three haplotypes were detected, which formed six haplogroups in a network. Australian specimens were placed in all haplogroups. The placement of New Zealand haplotypes in five of the haplogroups suggests that this species has dispersed across the Tasman Sea at least five times. Sexually reproducing plants of lower ploidy, detected only in south-eastern Australia, contained haplotypes from the two haplogroups that are successive sisters to the remaining diversity in the phylogeny. This likely suggests that A. flabellifolium was originally a sexually reproducing species in south-eastern Australia and spread to the rest of its distribution where apomictic plants dominate. More than one haplogroup was detected in several areas across its distribution, suggesting that these areas were colonised several times. Other areas harboured several haplotypes from a single haplogroup or haplogroups not recovered elsewhere, indicating possible long-term persistence in these areas. Haplotypes and morphological features were not found to be exclusive to either breeding system or ploidy and no taxonomic revision is proposed.
Ferns reproduce through small and usually haploid spores. The general paradigm states that whereas species produce good shaped spores, hybrids are sterile and form aborted spores. Apomictic fern species represent an unusual case, and it is believed that they produce an unbalanced spore spectrum. Until now, no comprehensive comparison of sexual and apomictic taxa using extensive spore fitness data has been published. Based on a representative data set of 109 plants from 23 fern taxa, we accomplished the first robust analysis of spore fitness using spore abortion index (SAI), the ratio of aborted to all examined spores. One thousand spores were analyzed for each plant. Focusing mainly on two major European fern taxa (Asplenium, Dryopteris), we compared this trait for different fern reproductive types (sexual/apomicts/hybrids) and ploidy levels (diploid versus polyploid). Our results confirmed the general assumption that shows higher SAI for apomictic taxa (18%) when compared to sexual taxa (3%). Furthermore, hybrids are characterized by having almost all spores aborted (99.8%) with the notable exception of pentaploid Dryopteris × critica (93.1%), the hybrid between sexual and apomictic taxa. We found no significant difference in SAI between sexual taxa of various ploidy levels or between sexual taxa of genera Dryopteris and Asplenium. Additionally, we carried out an optimization of the SAI method, outlying important guidelines for the use of this method in the future.
Mediterranean plant biodiversity and human impact : macro and micro-regional approaches
The human role appears to be central in the future of the Mediterranean environment, because its impact and management choices are responsible for the persistence of this high biodiversity. With 10 regional hotspots and 50 plant biodiversity refuge areas, the Mediterranean region is threatened by the quickness and the severity of the current and forecasted environmental changes. At a finer scale, the Maritime Alps regional hotspot constitutes the most important endemic center of the whole Alps region, but it has been subjected to drastic environmental transformations for the last decades. The comparisons between the distribution of refuges and human threats exhibit similar spatial patterns, both at the Mediterranean region scale and, to a lesser extend, at the Maritime Alps hotspot. Refuge areas constitute some of the most threatened territories due to a higher than average demographic pressure. Thus, facing the increasing threats on the Mediterranean biodiversity, it's essential to quickly undertake an integrative conservation framework at the Mediterranean scale which a prioritization toward refuge areas.
Examples of androdioecy, the coexistence of males and hermaphrodites, was unknown when the subject was last reviewed about two decades ago. Since then, several examples have been discovered in both plants and animals, and we are now in a position to reappraise theoretical work on the subject. Whereas early ideas were framed largely in terms of the invasion of males into hermaphroditic populations, all of the clearest examples of androdioecy now known appear to have evolved from dioecy. There are strong indications that this has occurred repeatedly as a result of the selection of self-fertile hermaphroditism for reproductive assurance during colonization. Male frequencies in these species are highly variable, self-fertilization in hermaphrodites is delayed, and mating opportunities appear to depend strongly on population density. Results from theoretical work on the evolution and maintenance of androdioecy in single populations and in metapopulations are summarized, and several case studies of androdioecious plants and animals are reviewed.
Understanding what factors generate geographic variation in species richness is a fundamental goal of ecology and biogeography. Water and energy are considered as the major environmental factors influencing large-scale patterns of species richness, but their roles vary among taxa and regions. Pteridophytes are an ideal group of organisms for examining the relationship between species richness and their environment because the distribution of pteridophytes is usually in equilibrium with contemporary climate to a greater degree than those of seed plants and most terrestrial vertebrates partly due to the lightness of their spores, which is highly capable of long-distance dispersal by wind, and partly due to their single-spore reproduction strategy. Using correlation and regression analyses and structural equation modeling technique, we examine the relationship of pteridophyte species richness in 151 localities from across China with environmental factors representing energy, water, and energy–water balance. We found that pteridophyte species richness is correlated to water availability more strongly than to ambient energy. Furthermore, we found that of all environmental variables considered, energy–water balance has played the most important role in regulating pteridophyte species richness gradients in China.
Variations in Earth's orbit with periods of 10–100 thousand years (kyr) (Milankovitch oscillations) have led to recurrent and rapid climatic shifts throughout Earth's history. These cause changes in the geographical distributions of clades, which we term orbitally forced range dynamics (ORD). The magnitude of ORD varies geographically, e.g., with latitude. Climatic shifts cause extinction, splitting, and merging of gene pools and clades. They select among individuals and clades for traits enhancing the ability to survive in situ and to establish new populations. There is also nonadaptive sorting caused by the large geographical variation in ORD, as only gene pools that are in the right place when climate shifts survive. ORD lead to sorting at many levels of genealogic inclusiveness. Clades that have survived climatic shifts during at least one entire period of the longest significant Milankovitch oscillations (100 kyr), we name β-clades. The products of more recent cladogenesis are α-clades, which are always nested within a β-clade. We conclude that ORD may promote α-clade formation but curb rates of β-clade formation. In areas with little ORD, where gene pools persist without going extinct or merging, clade splits and divergence may accumulate leading to high rates of β-clade formation and β-anagenesis (evolutionary change persisting >100 kyr). High ORD should lead to low numbers of β-clades, β-clades with low levels of spatial genetic divergence, little geographical subdivision and large ranges, organisms with high vagility and low specialization, high proportions of β-clades formed by polyploidization, and little β-anagenesis. We predict global and interregional geographic patterns in these variables caused by differential ORD. Thus, ORD potentially explains a wide array of patterns, suggesting ORD as a fundamental factor in evolution. The vulnerability of biotas to many human activities should vary with the magnitude of ORD.
The molecular population structure of 20 populations of the subalpine plant Gentiana pannonica was studied by use of amplified fragment length polymorphism (AFLP) and sequencing of non-coding regions of plastid DNA. Of the populations sampled, 18 were native (11 were from the Eastern Alps, which is the distribution centre of the species, and seven were from the Bohemian Forest, which is on the margin of the distribution range), and two were from the Giant Mts and of unclear status. No plastid DNA polymorphisms were found within the entire 6,185 bp investigated. The AFLP data revealed grouping of populations at the regional level. However, differentiation at the regional level (10.3 %) and at the interpopulation level (14.2 %) was low. Even though current populations are isolated and contain small numbers of individuals, the within-population variation (75.511 %) was high. Genetic variation was higher for alpine populations than for Bohemian Forest populations, probably because of fundamental differences in historical changes in population size between these regions. Within-population variation was intermediate for populations in the Giant Mts. The results indicate the possibility of a large distribution of species in the unglaciated areas of Central Europe, irrespective of altitude, during the late Pleistocene and early Holocene. Our results do not confirm that G. pannonica was introduced in the Giant Mts, and native status in the Giant Mts is possible.
Aim The range of the subalpine species Hypochaeris uniflora covers the Alps, Carpathians and Sudetes Mountains. Whilst the genetic structure and post-glacial history of many high-mountain plant taxa of the Alps is relatively well documented, the Carpathian populations have often been neglected in phylogeographical studies. The aim of the present study is to compare the genetic variation of the species in two major European mountain systems – the Alps and the Carpathians.
Location Alps and Carpathians.
Methods The genetic variation of 77 populations, each consisting of three plants, was studied using amplified fragment length polymorphism (AFLP).
Results Neighbour joining and principal coordinate analyses revealed three well-supported phylogeographical groups of populations corresponding to three disjunct geographical regions – the Alps and the western and south-eastern Carpathians. Moreover, two further clusters could be distinguished within the latter mountain range, one consisting of populations from the eastern Carpathians and the second consisting of populations from the southern Carpathians. Populations from the Apuseni Mountains had an intermediate position between the eastern and southern Carpathians. The genetic clustering of populations into four groups was also supported by an analysis of molecular variance, which showed that most genetic variation (almost 46%) was found among these four groups. By far the highest within-population variation was found in the eastern Carpathians, followed by populations from the southern and western Carpathians. Generally, the populations from the Alps were considerably less variable and displayed substantially fewer region-diagnostic markers than those from the south-eastern Carpathians. Although no clear geographical structure was found within the Alps, based on neighbour joining or principal coordinate analyses, some trends were obvious: populations from the easternmost part were genetically more variable and, together with those from the south-western part, exhibited a higher proportion of rare AFLP fragments than populations in other areas. Moreover, the total number of AFLP fragments per population, the percentage of polymorphic loci and the proportion of rare AFLP fragments significantly decreased from east to west.
Main conclusions Deep infraspecific phylogeographical gaps between the populations from the Alps and the western and south-eastern Carpathians suggest the survival of H. uniflora in three separate refugia during the last glaciation. Our AFLP data provide molecular evidence for a long-term geographical disjunction between the eastern and western Carpathians, previously suggested from the floristic composition at the end of 19th century. It is likely that Alpine populations survived the Last Glacial in the eastern part of the Alps, from where they rapidly colonized the rest of the Alps after the ice sheet retreated. Multiple founder effects may explain a gradual loss of genetic variation during westward colonization of the Alps.
Isozymes were used to study genetic variation in the clonal ferns Culcita macrocarpa and Woodwardia radicans in the northwestern Iberian Peninsula, their northern distributional limit. Despite their high chromosome numbers, both species
were isozymic diploids. In C. macrocarpa all 18 resolved loci were monomorphic, with the same allele in all ramets from all populations. In W. radicans only two of the 16 interpreted loci were polymorphic, with two alleles per locus; ramet-level genotypes showed Hardy-Weinberg
equilibrium, indicating an intergametophytic mating system; the number of genets distinguished was 1–3 per population; and
among-population variation was low (F
ST
= 0.231), suggesting effective gene flow (i.e. spore exchange). More generally, the very low (W. radicans, H
T
= 0.012) or zero (C. macrocarpa) genetic diversity detected in the present study may be due to genetic drift associated with the reduction of populations
in the last glaciation, and to founder effects in the subsequent Holocene expansion.
Acer opalus subsp. granatense is an endemic endangered tree with a wide but fragmented distribution in the Mediterranean mountains. The persistence of its small populations often depends on just a few adults, and consequently is highly vulnerable to factors limiting recruitment. In this paper, we examined the regeneration status of this maple in 16 populations throughout its whole geographical distribution in the Iberian Peninsula. Age and size structures were analysed as indicators of the viability of the species. Additionally, we studied the effects of herbivory by ungulates and the role of shrubs as nurse plants in maple regeneration dynamic. Our results show that A. opalus subsp. granatense has active recruitment throughout its range in the Iberian Peninsula. Shrubs served as the main microsites for recruitment, not only for early establishment but also for long-term survival. However, ungulates heavily damaged maple saplings in all locations and microhabitats. A direct consequence of herbivory is the uncoupling of age and size structures, saplings becoming older but not higher, possibly affecting population turnover in the long term. We suggest that the conservation of the small populations of Acer opalus subsp. granatense heavily depends on the control of herbivory pressure throughout the maple distribution area.
Climatic oscillations in the Quaternary have played a major role in changing the geographical distribution of plant species. Recent molecular work has provided new insights into the location of glacial refugia and routes of postglacial expansion. A comparative analysis shows that phylogeographic patterns in Europe appear to be less congruent than in North America. The change of geographical distribution has also provided opportunities for speciation through isolation, and hybridization after secondary contact. However, a complete understanding of the significance of the Quaternary climatic changes for plant speciation requires further research into the estimation of reliable and accurate divergence times.
Recent generalisations about polyploidy in plants have been largely based on studies of angiosperms. A compelling group to compare with angiosperms is ferns, because of their high polyploidy. The bi-parental inheritance of nuclear DNA sequence markers makes them advantageous for investigating polyploid complexes, but few such markers have been available for ferns. We have used DNA sequences from the low-copy nuclear LFY locus to study an Asplenium polyploid complex. The New Zealand species of this Austral group comprise seven tetraploids and eight octoploids. LFY sequences indicate that allopolyploidy is much more predominant than previously thought, being implicated in the origins of seven of the octoploids. One of the tetraploids has had a central role, being a progenitor for five of the octoploids. All of the octoploids appear to have relatively recent origins, with the dynamic environmental conditions of the Pleistocene possibly playing a role in their formation and/or establishment.
Allozyme analyses of the hermaphroditic slugs Arion (Carinarion) fasciatus, A. (C.) circumscriptus and A. (C.) silvaticus have suggested that the three species in North America and north-west Europe predominantly reproduce uniparentally, most probably by selfing. We used allozyme electrophoresis to investigate the population genetic structure of these species throughout a larger part of their native European distribution. Our results show that the previously reported "species" specific allozyme markers are no longer valid if populations from central Europe are investigated, and A. fasciatus and A. silvaticus appear to be "paraphyletic" taxa. In contrast to the general belief that selfing organisms show low gene diversities, the high selfing rates in N-NE European Carinarion do not necessarily result in low gene diversities. Moreover, our data suggest a geographical pattern in the prevalence of outcrossing, at least in A. fasciatus, with selfing in N-NE Europe and a mixed breeding system (i.e. selfing and outcrossing) in central Europe. Possible scenarios for the disjunct distribution of breeding systems in Carinarion are discussed.
This paper describes our investigation of genetic variation and clonal structure of the Mediterranean moss Pleurochaete squarrosa (Brid.) Lindb. (Pottiaceae), using inter-simple sequence repeat (ISSR) molecular markers and trnL(UAA) (intron of plastid gene for Leu tRNA) sequence, choosing different sampling strategies and scales on 16 European populations. Moreover, the intercontinental distribution of two trnL haplotypes, previously found over a large area and including 24 populations in three continents, was also investigated. Despite the prevalent asexual reproduction, P. squarrosa shows a high level of genetic diversity. Some site features seem to affect the clonal structure at the local scale, influencing the relocation of detached fragments and the level of intermingling, but they do not substantially affect genetic diversity. The peculiar vegetative reproduction coupled with somatic mutation could partly account for the genetic variation detected. Genetic distances highlight geographic isolation and limited gene flow among populations. We found only two trnL haplotypes in Europe due to length polymorphism, but, over an intercontinental scale, only non-delete trnL was found in Africa and the USA. ISSR analysis within each population detected a higher genetic distance between the samples with different trnL haplotypes, suggesting the presence of two different genetic lineages within this species, geographically overlapping in the Mediterranean Basin.
Chloroplast DNA sequences were obtained from 331 Asplenium ceterach plants representing 143 populations from throughout the range of the complex in Europe, plus outlying sites in North Africa and the near East. We identified nine distinct haplotypes from a 900 bp fragment of trnL-trnF gene. Tetraploid populations were encountered throughout Europe and further afield, whereas diploid populations were scarcer and predominated in the Pannonian-Balkan region. Hexaploids were encountered only in southern Mediterranean populations. Four haplotypes were found among diploid populations of the Pannonian-Balkans indicating that this region formed a northern Pleistocene refugium. A separate polyploid complex centred on Greece, comprises diploid, tetraploid and hexaploid populations with two endemic haplotypes and suggests long-term persistence of populations in the southern Mediterranean. Three chloroplast DNA (cpDNA) haplotypes were common among tetraploids in Spain and Italy, with diversity reducing northwards suggesting expansion from the south after the Pleistocene. Our cpDNA and ploidy data indicate at least six independent origins of polyploids.
Sequences of chloroplast DNA (cpDNA) atpB–rbcL intergenic spacers of individuals of a tree fern species, Alsophila spinulosa, collected from ten relict populations distributed in the Hainan and Guangdong provinces, and the Guangxi Zhuang region in southern China, were determined. Sequence length varied from 724 bp to 731 bp, showing length polymorphism, and base composition was with high A+T content between 63.17% and 63.95%. Sequences were neutral in terms of evolution (Tajima’s criterion D=−1.01899, P>0.10 and Fu and Li’s test D*=−1.39008, P>0.10; F*=−1.49775, P>0.10). A total of 19 haplotypes were identified based on nucleotide variation. High levels of haplotype diversity (h=0.744) and nucleotide diversity (D
ij=0.01130) were detected in A. spinulosa, probably associated with its long evolutionary history, which has allowed the accumulation of genetic variation within lineages. Both the minimum spanning network and neighbor-joining trees generated for haplotypes demonstrated that current populations of A. spinulosa existing in Hainan, Guangdong, and Guangxi were subdivided into two geographical groups. An analysis of molecular variance indicated that most of the genetic variation (93.49%, P<0.001) was partitioned among regions. Wright’s isolation by distance model was not supported across extant populations. Reduced gene flow by the Qiongzhou Strait and inbreeding may result in the geographical subdivision between the Hainan and Guangdong + Guangxi populations (F
ST=0.95, Nm=0.03). Within each region, the star-like pattern of phylogeography of haplotypes implied a population expansion process during evolutionary history. Gene genealogies together with coalescent theory provided significant information for uncovering phylogeography of A. spinulosa.
Host-race evolution is a prime candidate for sympatric speciation because host shifts must take place in the presence of both hosts. However, the geographic context in which the shift takes place may have strong allopatric or peripatric components if the primary host within a localized area is scarce or even goes extinct. Inference of the relative importance of the geographic mode of speciation may be gained from phylogeographic imprints. Here, we investigate the phylogeography of host races of the tephritid fly Tephritis conura from sympatric, parapatric and allopatric populations of Cirsium heterophyllum and Cirsium oleraceum (Asteraceae) in Europe, for addressing the age and direction, and the geographic context of host-race formation. Haplotype networks of the host races differed significantly in molecular diversity and topology. However, host-race haplotypes were nested within the same network, with a central haplotype H1 being the most common haplotype in both host races. C. heterophyllum flies were genetically more diverse and substructured than flies from C. oleraceum, suggesting that the latter is the derived race. The phylogeographic imprint indicates either that C. heterophyllum flies colonized C. oleraceum during range expansion or that heterophyllum flies went extinct in an area where oleraceum flies persisted (followed by re-immigration). These imprints are in concordance with peripatric diversification, probably in the European Alps and related to the last ice age, where the host-race diversification was largely completed before the postglacial range expansion on C. oleraceum to current areas of sympatry and parapatry with C. heterophyllum.
In order to contribute to the debate about southern glacial refugia used by temperate species and more northern refugia used by boreal or cold-temperate species, we examined the phylogeography of a widespread snake species (Vipera berus) inhabiting Europe up to the Arctic Circle. The analysis of the mitochondrial DNA (mtDNA) sequence variation in 1043 bp of the cytochrome b gene and in 918 bp of the noncoding control region was performed with phylogenetic approaches. Our results suggest that both the duplicated control region and cytochrome b evolve at a similar rate in this species. Phylogenetic analysis showed that V. berus is divided into three major mitochondrial lineages, probably resulting from an Italian, a Balkan and a Northern (from France to Russia) refugial area in Eastern Europe, near the Carpathian Mountains. In addition, the Northern clade presents an important substructure, suggesting two sequential colonization events in Europe. First, the continent was colonized from the three main refugial areas mentioned above during the Lower-Mid Pleistocene. Second, recolonization of most of Europe most likely originated from several refugia located outside of the Mediterranean peninsulas (Carpathian region, east of the Carpathians, France and possibly Hungary) during the Mid-Late Pleistocene, while populations within the Italian and Balkan Peninsulas fluctuated only slightly in distribution range, with larger lowland populations during glacial times and with refugial mountain populations during interglacials, as in the present time. The phylogeographical structure revealed in our study suggests complex recolonization dynamics of the European continent by V. berus, characterized by latitudinal as well as altitudinal range shifts, driven by both climatic changes and competition with related species.
A study of the variation in pattern and frequency of constitutive heterochromatin and nucleolar organizing regions of the X chromosomes of male Chorthippus parallelus grasshoppers in 25 populations within the Iberian peninsula requires us to revise our interpretation of the biogeography and evolutionary history of this species. Hybridization between the subspecies Cp erythropus and Cp parallelus, previously only known from populations in the Pyrenean cols, is shown to extend at least 400 km further into north-west Spain. A novel X-chromosome variant is described that appears to be close to fixation in 18 populations, mainly from the centre and south of Spain. Our findings indicate a possible independent origin for each of three distinct, nonderivative X variants present in Spain: the northern Cp erythropus and Cp parallelus variants, and a central-southern Cp erythropus variant. The first two are distinguished by interstitial and distal C bands, respectively, whereas the central-southern form has neither. This central-southern form is probably the current representative of the ancestral Iberian X variant. The pattern of variation supports the hypotheses of multiple refugia for Iberian populations and that more hybrid zones exist between these chromosomal variants.
The common name “pteridophyte” has been applied to plants composing four divisions (Bold et al., 1986): Psilotophyta, Microphyllophyta, Arthrophyta, and Pteridophyta. Most pteridophytes are homosporous, producing one type of spore that germinates to produce a potentially bisexual gametophyte. The homosporous pteridophytes are the whisk ferns, Psilotum and Tmesipteris (Psilotophyta); the lycopods, Lycopodium sensu lato and Phylloglossum (class Aglossopsida of the Microphyllophyta); the horsetails and scouring rushes, Equisetum (Arthrophyta); and most families of ferns (Pteridophyta). These are ancient lineages, some of which are regarded as living fossils (Bold et al., 1986). The lycopods, for example, can be traced back in the fossil record to the lower Devonian.
The models of Lande and Schemske predict that among species in which the selfing rate is largely under genetic control and not subject to tremendous environmental variation, the distribution of selfing rates should be bimodal. When this prediction was tested empirically using data from the literature for species of angiosperms and gymnosperms, the distribution of outcrossing rates for all species was clearly bimodal. To provide another empirical test of the prediction, we analyzed mating-system data for 20 species of Pteridophyta (ferns). Homosporous ferns and their allies are unique among vascular plants because three types of mating are possible: intragametophytic selfing (selfing of an individual gametophyte); intergametophytic selfing (analogous to selfing in seed plants); and intergametophytic crossing (analogous to outcrossing in seed plants). The distribution of intragametophytic selfing rates among species of homosporous ferns is clearly uneven. Most species of homosporous ferns would be classified as extreme outcrossers. In contrast, a few species are nearly exclusively inbreeding. In only a few populations of Dryopteris expansa and Hemionitis palmata and a single population of Blechnum spicant do we see convincing evidence of a mixed mating system. The uneven distribution of selfing rates we observed for homosporous ferns, coupled with a corresponding bimodality of the magnitude of genetic load, strongly supports the model.
In order to gain insight into the causes of parapatric diploid and tetraploid distributions in Plantago media chloroplast DNA (cpDNA) restriction site polymorphism was studied in 36 European populations. Parapatric distributions are often explained by adaptive differences between cytotypes to an underlying heterogeneity in environmental factors. Alternatively, such distribution patterns may be explained nonadaptively, through frequency-dependant production of hybrids with low fitness. However, nonadaptive explanations have been neglected in polyploid literature. In this study nine chloroplast haplotypes were found. Their phylogeny suggests that tetraploids arose at least three times from diploids. In general, related haplotypes were also geographically clustered, although there were some marked geographical discontinuities. In the Pyrenees, diploids and tetraploids carried diverged haplotypes throughout their parapatric ranges. At the contact zone the level of cpDNA introgression in a mixed diploid-tetraploid population was low. It is discussed that the cpDNA phylogeography supports the nonadaptive hypothesis that parapatric cytotype distributions may be explained by postPleistocene range expansions followed by mutual minority cytotype exclusion, due to hybrid unfitness.
Abstract Previous studies on the sequence of the gametangium formation in homosporous fern gametophytes (Masuyama, 1975a, b) suggested that diploid and polyploid taxa may favor gametophytic crossing and gametophytic selfing, respectively. In this view, intraspecific polyploids of three fern species (Phegopteris decursive-pinnata, Lepisorus thunbergianus and Pteris dispar) have been investigated for the amount of genetic load or the rate of gametophytic selfing. As expected, a marked contrast of mating systems is found between diploids and tetraploids; the former predominantly undergo gametophytic crossing and the latter predominantly undergo gametophytic selfing. It seems likely that diploid homosporous pteridophytes favor gametophytic crossing with some exceptions favoring gametophytic selfing as a derived condition, whereas polyploid homosporous pteridophytes favor gametophytic selfing predominantly.
It has been revealed that gametophytes of diploid plants of Phegopteris decursive-pinnata have a low capability for intragametophytic selfing (Masuyama, 1979). In the present study, intergametophytic mating tests were conducted for the self-sterile gametophytes of four diploids to demonstrate the genetic factors responsible for such a low capability for selfing. The results of the tests indicated that the gametophytes carried two or more kinds of recessive embryonic lethal factors which were non-allelic with each other and that the occurrence frequency of the gametophytes with an identical recessive lethal factor was 13% to 27% in the gametophyte families of these four diploids The karyological study of a diploid sporophyte suggested not the tetraploid but the diploid constitution of somatic chromosomes. Based on these data, the diploid inheritance of two or three special deleterious genes with a synergistic interaction responsible for the embryonic lethality was hypothesized to elucidate the self-sterility in the diploids of this species.
This research aims to investígate the reciproca! influence, either positive or negative, between the geographical distribution and the speciation by hybridization followed by chromosome doubling in Pteridophyta, and particularly to ascertain whether the formation of a species by this process happens only once and in a single place, or can occur many times and in different localities; in short, it aims to find out whether the origin of the allotetraploid species of Pteridophytes is monotopic only or can be also polytopic. The research has been carried out on seven allotetraploid species from the Mediterranean Region of the genera Cheilanthes, Asplenium and Phyllitopsis. The formation from their diploid parents is descríbed in detail and illustrated by diagrams. Likewise, their geographical distríbution and that of their diploid parents is established and shown by maps. On the basis of this information a carefull comparison of the ranges of the parents and of the pertinent allotetraploid species derived from them is made. It has allowed us to establish where the ranges of the diploid parents are coincident or contiguous, and whether the hybrid between them and the allotetraploid which originated from it by chromosome doubling, occur there. This comparison has given fruitfull indications on the área or áreas in whichthe formation of the allotetraploid species took place, and on the presumable time in which it occur red, and in some cases why two allied diploid species did not give rise to genetically possible allotetraploids. This research has shown that a polytopic origin in Asplenium adiantumnigrum and A. lepidum is probable, in Cheilanthes tinaei and Ch. guanchica is reliable, and in Asplenium balearicum is certain. Thus, the conclusion is reached that in the Pteridophyta the génesis of the allotetraploid species by hybridization followed by chromosome doubling, which happened in the past at the moment of their first formation, is a process which can occur again more than once in the course of time and can come about even in places other than that which was its first centre of origin.
Little is known about the mode of transmission of chloroplasts in ferns, despite the importance of such knowledge for molecular phylogenetic and biosystematic studies. Andersson-Kötto (1930, 1931) inferred from crossing experiments that chloroplasts are inherited biparentally in Asplenium scolopendrium L. Here we present evidence from artificial hybridisation that demonstrates maternal inheritance of chloroplast DNA in the genus Asplenium (Aspleniaceae, Pteridophyta) using length variation in a non-coding spacer (trnLUAA-trnFGAA) in the chloroplast DNA.
Les affinités entre cytotypes diploïde et tétraploïde d' Asplenium ruta-muraria L. ont été étudiées par l'observation cytologique de l'hybride triploïde et d'un autotétraploïde produit par aposporie. Le triploïde est caractérisé par une fréquence élevée de trivalents et la méiose est très irrégulière chez l'autotétraploïde artificiel. En conclusion, la subsp. ruta-muraria doit être un autotétraploïde dérivé de croisements intraspécifiques, mais elle n'a pas été formée à partir de la forme diploïde par un simple doublement du nombre chromosomique. L'homologie entre ses génomes est plus grande que chez A. trichomanes et A. septentrionale. /// The relationships between diploid and tetraploid cytotypes of Asplenium ruta-muraria L. have been studied by cytological observation of the triploid hybrid between them and of an autotetraploid induced by apospory. The triploid was characterized by a high trivalent frequency and the induced autotetraploid showed a very irregular meiosis. It was concluded that subsp. ruta-muraria is an autotetraploid derived from intraspecific crossing but was not formed by a simple chromosome doubling from a diploid cytotype. The homology between its genomes is higher than for A. trichomanes and A. septentrionale.
An attempt is made to investigate the nature of cold-stage distributions for those forest trees which today extend to northern Europe. Evidence is taken from the pollen record of the present and earlier interglacials, a model of past climate, modern tree distributions, and physiography of southern Europe. The trees occupied mid-altitude sites in the mountains of southern Europe, especially in the western Balkans and Italy during the last cold stage. These areas would have had a suitable climate, and it is argued that the trees could easily have survived there at densities low enough to escape detection in the pollen record. Most taxa which spread north at the beginning of an interglacial become extinct in the northern part of their ranges, and do not retreat south at the end of the interglacial. The survival of these trees in southern Europe through a warm stage may be at least as important for long-term Quaternary survival in Europe as survival during a cold stage.
Solitary plants of Asplenium platyneuron occur disjunctively on recently produced coal spoils in southern Iowa. They are assumed to have been produced by self-fertilization of isolated gametophytes and therefore highly homozygous. Cultures of isolated and paired gametophytes originating from these solitary sporophytes produced second-generation sporophytes with 89 and 93% success, respectively, indicating a low genetic load as expected. The failure of gametophytes from coal-spoil plants to produce sporophytes with even greater success may result from homoeologous chromosome pairing and recombination at meiosis which allows production of variable spores and expression of genetic load from plants produced by self-fertilization of single gametophytes. Cultures of isolated and paired gametophytes originating from sporophytes in populations central to the species' range produced second-generation sporophytes with 83 and 90% success, respectively, indicating a significantly greater genetic load in populations but still a relatively low genetic load for the species. Through low genetic load, regularity of sporophyte production from isolated gametophytes, and ability of such plants to release variability through homoeologous chromosome pairing, Asplenium platyneuron is remarkably adapted for, and successful in, colonizing distant habitats through long-range spore dispersal.
This study describes the population structure of Norway spruce (Picea abies) as revealed by protein polymorphisms and morphological variation. Electrophoretically detectable genetic variability was examined at 22 protein loci in 70 populations from the natural range of the species in Europe. Like other conifers, Norway spruce exhibits a relatively large amount of genetic variability and little differentiation among populations. Sixteen polymorphic loci (73%) segregate for a total of 51 alleles, and average heterozygosity per population is 0.115. Approximately 5% of the total genetic diversity is explained by differences between populations (GST = 0.052), and Nei's standard genetic distance is less than 0.04 in all cases. We suggest that the population structure largely reflects relatively recent historical events related to the last glaciation and that Norway spruce is still in a process of adaptation and differentiation. There is a clear geographic pattern in the variation of allele frequencies. A major part of the allelefrequency variation can be accounted for by a few synthetic variables (principal components), and 80% of the variation of the first principal component is "explained" by latitude and longitude. The central European populations are consistently depauperate of genetic variability, most likely as an effect of severe restrictions of population size during the last glaciation. The pattern of differentiation at protein loci is very similar to that observed for seven morphological traits examined. This similarity suggests that the same evolutionary forces have acted upon both sets of characters.
CLIMAP (1981, “Seasonal Reconstruction of the Earth's Surface at the Last Glacial Maximum,” Geological Society of America Map and Chart Series MC-36) boundary conditions were used as inputs to the GISS general circulation model, and the last glacial maximum (LGM) climate was simulated for six model years. The simulation was compared with snow line depression and pollen-inferred temperature data at low latitudes, specifically for Hawaii, Colombia, East Africa, and New Guinea. The model does not produced as much cooling at low latitudes as is implied by the terrestrial evidence. An alternative experiment in which the CLIMAP sea-surface temperatures were uniformly lowered by 2°C produces a better fit to the land data although in Hawaii model temperatures are still too warm. The relatively warm CLIMAP tropical sea-surface temperatures also provide for only a slight decrease in the hydrologic cycle in the model, in contrast to both evidence of LGM tropical aridity and the results of the experiment with colder ocean temperatures. With the CLIMAP sea-surface temperatures, the LGM global annual mean surface air temperature is 3.6°C colder than at present; if the ocean temperatures were allowed to cool in conformity with the model's radiation balance, the LGM simulation would be 5°–6°C colder than today, and in better agreement with the tropical land evidence.
The Quaternary cold periods in Europe are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in both animals and plants. The phylogeographies of 10 taxa, including mammals (Ursus arctos, Sorex spp., Crocidura suaveolens, Arvicola spp.), amphibians (Triturus spp.), arthropods (Chorthippus parallelus), and plants (Abies alba, Picea abies, Fagus sylvatica, Quercus spp.), were analysed to elucidate general trends across Europe. Only a small degree of congruence was found amongst the phylogeographies of the 10 taxa, but the likely postglacial colonization routes exhibit some similarities. A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier. The comparison of colonization routes highlighted four main suture-zones where lineages from the different refugia meet. Some of the intraspecific genetic distances among lineages indicated a prequaternary divergence that cannot be connected to any particular cold period, but are probably related mainly to the date of arrival of each taxon in the European continent. As a consequence, molecular genetics so far appears to be of limited use in dating Quaternary events.
Twenty-nine populations of three closely related taxa, Asplenium lepidum, A. haussknecktii and A. samarkandense, have been raised together in cultivation. There is considerable inter-population variation, and the ranges of variation of the three species overlap. Cytogenetic investigation of artificial hybrids has shown that the three taxa are all allotetraploid and that they share the same diploid parents, A. aegaeum and A. ruta-muraria subsp. dolomiticum. Analysis of F1 and F2 hybrids between different populations indicates high inter-fertility.The aggregate is re-defined as a single polymorphic species (A. lepidum) consisting of two subspecies (subsp. lepidum and subsp. haussknechtii) distinguished primarily by gland and sporangial characters. A. samarkandense is reduced to a variety of subsp. haussknechtii. It is suggested that the two subspecies have had separate geographical origins from different morphological variants of the same diploid parents, but the polymorphic nature of the aggregate is principally due to divergent evolution in small populations isolated on limestone mountains in southern Europe and western Asia.
In EuropeAthyrium filix-femina has a constant chromosome number (2n = 80) and is sexual. The normal type of reproduction is intergametophytic crossing. In the gametophyte phase there is a hormone system which induces dark germination of spores and antheridium formation. Sporophytes originating from single prothalli show that a genetic load is present in all population examined. It appears not to be a simple allelic load but a complicated balanced system. Morphological variability can be interpreted as the expression of the genetic heterogeneity of populations. There are no crossing barriers, not even between insular populations hundreds of kilometers apart.
An important element of the biogeography of species is the geographic aspects of speciation. The geography of species has a role in the processes of speciation which have a reciprocal role in species geography.
The homosporous ferns provide an especially favorable group for biogeographic studies because nearly all species have an equivalent capacity for dispersal and migration. Species ranges are based on the ecology of the environment, rather than on animal vectors of dispersal or pollination. However, with allowance for these differences, the processes of geographic speciation are basically the same in ferns and other vascular plants, although often on a broader geographic scale in the ferns.
Speciation most frequently produces a new species with a small range, which can rapidly expand to occupy the geography of the environment to which the species is adapted. The members of a closely related speciesgroup retain their morphological and geographic relations for a relatively short time. With speciation, changes in distribution, and extinction, the original relations of the species and the biogeographical history of the group will be lost.
High regional species diversity occurs in the wet mountainous regions of the tropics, where there is greatest ecological diversity and maximal opportunities for speciation and persistence.
The conditions for the establishment of a tetraploid in a diploid population were investigated by means of a deterministic model, on the assumption that the diploid cytotype produces some 2n gametes.
If the fertility and viability of both cytotypes were the same and the initial population was diploid, then a mixed population would occur if the production of 2n gametes was below 17.16%. The tetraploid excluded the diploid above this limit. By modifying the fertility and the viability of the polyploid this threshold varied, dropping to 10% when one of the two parameters was twice that of the diploid, and falling to as low as 6% if both fertility and viability were double that of the diploid.
The conditions for the establishment of a polyploid are therefore quite restrictive under the assumptions of this model. In nature, such processes would probably allow the spread of the polyploid only if the immigration of polyploids considerably enhanced the frequency of tetraploids, or if genetical or environmental changes, or chance processes in small populations caused a substantial increase in the frequency of 2n gametes produced by the diploid.
Thesis (M.S.)--University of Vermont, 1994. Includes bibliographical references (leaves 42-44).
Thesis (Ph. D.)--University of Cambridge, 1995.
A noncoding nuclear DNA marker sequence (Cpn1-1) was used to investigate subdivision in the grasshopper Chorthippus parallelus and deduce postglacial expansion patterns across its species range in Europe. Investigation of the spatial distribution of 71 Cpn1-1 haplotypes and estimation of levels of genetic differentiation (KST values) between populations and geographic regions provided evidence for subdivision of C. parallelus into at least five major geographic regions and indicated that the French form of C. parallelus originated after range expansion from a Balkan refugium. Further evidence for subdivision of C. parallelus between Italy and northern Europe suggests that the Alps may have formed a significant barrier to gene flow in this grasshopper.
Refugial differentiation and routes of postglacial migration are major determinants of the patterns of geographical variation we see in natural populations today. We used patterns of chloroplast DNA (cpDNA) variation to investigate the postglacial colonization history of the European oak species Quercus robur and Q. petraea. By sequencing two cpDNA segments using universal primers, we revealed four polymorphic sites which identify four cytotypes with characteristic geographical distributions. Of these, the principal eastern, central and western cytotypes divide the range into three longitudinal zones, each extending from the south to the north of Europe. This corroborates the idea that the postglacial colonization started from three distinct southerly refugia. The fourth cytotype, restricted to East Anglia, was probably derived from the western type postglacially. As a special problem, we addressed the controversial origin of Q. robur at its northern limits in south-western Finland, where it currently occupies a narrow coastal zone disjunct from the remaining oak range. Using a PCR-RFLP assay that discriminates the eastern cytotype, a contact zone of two cytotypes was identified in the region of the Salpausselkä ridges. This suggests that the marginal northern occurrence was independently colonized both from the east and from the west, across the Baltic Sea.
Prodromo alla flora della regione Apuana. I. Lycopodiaceae—Leguminosae
- E Ferrarini
- Marchetti
Ferrarini E, Marchetti D. 1994. Prodromo alla flora della regione Apuana. I. Lycopodiaceae—Leguminosae. La Spezia: Accademia Lunigianese di Scienze Giovanni Capellini.
The ferns and allies of the Far West Himalaya: Some additions and corrections
- Cr Fraser-Jenkins
Fraser-Jenkins CR. 1992. The ferns and allies of the Far West Himalaya: Some additions and corrections. Botanica Helvetica 102: 143–157.
Verbreitungsatlas der Farn-und Blü Kä. Klagenfurt: Naturwissenschaftlicher Verein fü Kä. Hedrick PW. 1987. Genetic load and the mating system in homosporous ferns
- H Hartl
- G Kniely
- Leute Gh
- H Niklfeld
- Perko
Hartl H, Kniely G, Leute GH, Niklfeld H, Perko M. 1992. Verbreitungsatlas der Farn-und Blü Kä. Klagenfurt: Naturwissenschaftlicher Verein fü Kä. Hedrick PW. 1987. Genetic load and the mating system in homosporous ferns. Evolution 41: 1282–1289.
Atlas florae Europaeae. 1. Pteridophyta. Helsinki: University of Helsinki Press. Jermy AC. 1984. Origin and distribution of Pteridophytes in the Mediterranean area
- Jalas J Suominen
Jalas J, Suominen J. (Eds.), 1972. Atlas florae Europaeae. 1. Pteridophyta. Helsinki: University of Helsinki Press. Jermy AC. 1984. Origin and distribution of Pteridophytes in the Mediterranean area. Webbia 38: 397–416.
Neue Angaben zur Pteridophytenflora Osteuropas
- S Jeßen
Jeßen S. 1991. Neue Angaben zur Pteridophytenflora Osteuropas. Farnblä 23: 14–47.
The genetics and reproductive biology of ferns The experimental biology of ferns
- Ej Klekowski
Klekowski EJ. 1979. The genetics and reproductive biology of ferns. In: Dyer AD, ed. The experimental biology of ferns. London: Academic Press, 133–170.
Die Farnpflanzen oder Gefässbü (Pteridophyta). Dr L. Rabenhorst's Kryptogamen-Flora von Deutschland, Oesterreich und der Schweiz
- C Luerssen
Luerssen C. 1889. Die Farnpflanzen oder Gefässbü (Pteridophyta). Dr L. Rabenhorst's Kryptogamen-Flora von Deutschland, Oesterreich und der Schweiz. 2nd edition, Vol.
Manton I. 1950. Problems of cytology and evolution in the Pteridophyta
- Leipzig
- Verlag
- Kummer
Leipzig: Verlag Kummer. Manton I. 1950. Problems of cytology and evolution in the Pteridophyta. Cambridge: Cambridge University Press. Marchetti D. 1992. Le pteridofite indigene della regione apuana. Annali Accademia Lunigianese di Scienze 60–61: 399–434.
Asplenium ruta-muraria L. subsp. dolomiticum Lovis & Reichstein, die Dolomiten-Mauerraute – neu fü O ¨ sterreich
- H Melzer
Melzer H. 1987. Asplenium ruta-muraria L. subsp. dolomiticum Lovis & Reichstein, die Dolomiten-Mauerraute – neu fü O ¨ sterreich. Linzer biologische Beiträ 19: 295–297.
Bromus racemosus Huds. die Wald-Trespe, ein neues Gras in der Flora Kä und weitere bemerkenswerte Pflanzenfunde
- H Melzer
Melzer H. 1990. Bromus racemosus Huds. die Wald-Trespe, ein neues Gras in der Flora Kä und weitere bemerkenswerte Pflanzenfunde. Carinthia II 180: 469–477.
Neues zur Flora von Friaul-Julisch Venetien, Slowenien und Kroatien
- H Melzer
- Bregant
Melzer H, Bregant E. 1989. Neues zur Flora von Friaul-Julisch Venetien, Slowenien und Kroatien. Gortania 11: 161–176.
Asplenium adulterinum Milde subsp. presolanense subsp. nova, Aspleniaceae, Pteridophyta)
- Rasbach F H Mokry
Mokry F, Rasbach H, Reichstein T. 1986. Asplenium adulterinum Milde subsp. presolanense subsp. nova, Aspleniaceae, Pteridophyta). Botanica Helvetica 96: 7–18.
The ferns of Britain and Ireland. Cambridge: Cambridge University Press. Pichi-Sermolli REG. 1979. A survey of the pteridological flora of the Mediterranean Region
- Cn Page
Page CN. 1997. The ferns of Britain and Ireland. Cambridge: Cambridge University Press. Pichi-Sermolli REG. 1979. A survey of the pteridological flora of the Mediterranean Region. Webbia 34: 175–242.
Atlas e ´cologique des fougères et plantes allié Illustration et ré des Pteridophytes de France. Paris, Lechevalier. Reichstein T. 1981. Hybrids in European Aspleniaceae (Pteridophyta)
- R Prelli
- M Boudrie
Prelli R, Boudrie M. 1992. Atlas e ´cologique des fougères et plantes allié. Illustration et ré des Pteridophytes de France. Paris, Lechevalier. Reichstein T. 1981. Hybrids in European Aspleniaceae (Pteridophyta). Botanica Helvetica 91: 89–139.
Untersuchungen an einheimischen Farnen, insbesondere der Dryopteris filix-mas Gruppe
- Jj Schneller
Schneller JJ. 1975. Untersuchungen an einheimischen Farnen, insbesondere der Dryopteris filix-mas Gruppe.
Colonization events and genetic variability within populations of Asplenium ruta-muraria L
- Schneller Jj
- R Holderegger
Schneller JJ, Holderegger R. 1996. Colonization events and genetic variability within populations of Asplenium ruta-muraria L. In: Camus JM, Gibby M, Johns RJ, eds. Pteridology in Perspective. Kew: Royal Botanic Gardens, 571–580.
Autö Untersuchungen an der Mauerraute (Asplenium ruta-muraria L.)
- B Suter
- Schneller
- Jj
Suter B, Schneller JJ. 1986. Autö Untersuchungen an der Mauerraute (Asplenium ruta-muraria L.). Farnblä 14: 1–14.
A non-coding region of chloroplast DNA as a tool to investigate reticulate evolution in European Asplenium
- Russell Jc Vogel
- Barrett Ja Sj
- Gibby
Vogel JC, Russell SJ, Barrett JA, Gibby M. 1996. A non-coding region of chloroplast DNA as a tool to investigate reticulate evolution in European Asplenium. In: Camus JM, Gibby M, Johns RJ, eds. Pteridology in Perspective. Kew: Royal Botanic Gardens, 313–329.
The origin, status and distribution of Asplenium presolanense stat.nov. (Aspleniaceae, Pteridophyta) Botanica Helvetica 108 in press Late Quaternary ice age climates of tropical Australasia: in-terpretations and reconstructions
- Jc Vogel
- Fj
- Schneller
- Russell Sj Jj
- Holmes
- Barrett Ja Js
- Gibby
- Pj Webster
- Streten
- Na
Vogel JC, Rumsey FJ, Schneller JJ, Russell SJ, Holmes JS, Barrett JA, Gibby M. 1998b. The origin, status and distribution of Asplenium presolanense stat.nov. (Aspleniaceae, Pteridophyta). Botanica Helvetica 108 in press. Webster PJ, Streten NA. 1978. Late Quaternary ice age climates of tropical Australasia: in-terpretations and reconstructions. Quaternary Research 10: 279–309.