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1.
The geographic position of Lebanon in the Mediterranean basin at the transition of two major landmasses, Eurasia and Africa, has contributed to its high plant diversity and makes its flora particularly interesting to study. This paper contributes to the plant DNA C-value database of native Lebanese taxa. These data should reinforce biodiversity evaluation, systematic and evolution studies involving processes of speciation such as polyploidisation. C-values have been estimated by flow cytometry using propidium iodide as intercalary fluorochrome stain. Each sample comprised at least five individuals. Where possible, several populations were measured for each species. This study presents C-values for 225 taxa belonging to 55 families and 141 genera. C-values are novel for 193 taxa including 126 plants endemic to the Eastern Mediterranean region. These are the first values for 50 genera. In this panel, genome size ranged from 1C = 0.28 pg in Hypericum thymifolium to 54.69 pg in Fritillaria alfredae. The life growth form and life cycle type are analysed according to the genome size class. Cases of polyploidy are reported for some species usually considered as only diploid. Examination of C-value variation through flow cytometry constitutes a powerful tool to screen taxonomic heterogeneity, opening further investigations.  相似文献   

2.
As mountains have been hypothesized as harboring important Quaternary refugia for plants, one would expect high within-population genetic variation and low or moderate among-population differentiation for those species occurring there. We selected Kirengeshoma koreana and Parasenecio pseudotaimingasa, endemic to mountains of Korea to test the scenario that the main mountain ranges of the Peninsula would also have acted as refugia. We undertook a population genetic analysis using 15 and 12 putative allozyme loci of K. koreana and P. pseudotaimingasa, respectively. We found contrasting levels of genetic diversity in the two species; extremely low within-population genetic variation and high among-population divergence in K. koreana and high within-population genetic variation and moderate among-population divergence in P. pseudotaimingasa. We can conclude that, whereas Korean mountains would have provided large refugial areas (i.e., ‘macrorefugia’) for P. pseudotaimingasa, K. koreana would have endured the Quaternary climate oscillations in small, isolated populations (i.e., ‘microrefugia’). Given the lack of genetic diversity and the extremely low number of populations and individuals of K. koreana, a comprehensive conservation program is urgently needed for this rare and critically endangered species.  相似文献   

3.
Background and Aims Myrcia section Aulomyrcia includes ∼120 species that are endemic to the Neotropics and disjunctly distributed in the moist Amazon and Atlantic coastal forests of Brazil. This paper presents the first comprehensive phylogenetic study of this group and this phylogeny is used as a basis to evaluate recent classification systems and to test alternative hypotheses associated with the history of this clade.Methods Fifty-three taxa were sampled out of the 120 species currently recognized, plus 40 outgroup taxa, for one nuclear marker (ribosomal internal transcribed spacer) and four plastid markers (psbA-trnH, trnL-trnF, trnQ-rpS16 and ndhF). The relationships were reconstructed based on Bayesian and maximum likelihood analyses. Additionally, a likelihood approach, ‘geographic state speciation and extinction’, was used to estimate region- dependent rates of speciation, extinction and dispersal, comparing historically climatic stable areas (refugia) and unstable areas.Key Results Maximum likelihood and Bayesian inferences indicate that Myrcia and Marlierea are polyphyletic, and the internal groupings recovered are characterized by combinations of morphological characters. Phylogenetic relationships support a link between Amazonian and north-eastern species and between north-eastern and south-eastern species. Lower extinction rates within glacial refugia suggest that these areas were important in maintaining diversity in the Atlantic forest biodiversity hotspot.Conclusions This study provides a robust phylogenetic framework to address important ecological questions for Myrcia s.l. within an evolutionary context, and supports the need to unite taxonomically the two traditional genera Myrcia and Marlierea in an expanded Myrcia s.l. Furthermore, this study offers valuable insights into the diversification of plant species in the highly impacted Atlantic forest of South America; evidence is presented that the lowest extinction rates are found inside refugia and that range expansion from unstable areas contributes to the highest levels of plant diversity in the Bahian refugium.  相似文献   

4.
In temperate mountains, fens have been reported as relict habitats subject to geographical fragmentation and broad climatic gradients, but few studies have analyzed the influence of these factors on plant diversity. Here we investigate the effect of isolation on the vegetation diversity of rich fens (Caricion davallianae) in the mountains of the Iberian Peninsula, the distribution limit of these habitats in south-western Europe. We used plot-based vegetation data from the Pyrenees and the Cantabrian mountain range to evaluate their regional species-pool, occurrence of specialists, beta-diversity and the effect of geo-climatic variables on their species-richness and species-composition. We found a lower ratio of rare specialists in the Pyrenees than in the Cantabrian range, but similar estimates in the species pools, total species-richness per plot and beta-diversity. The isolation of the two mountain regions resulted in different species assemblages best predicted by summer precipitation and bedrock types, showing region-based differences in the response of vegetation and plant specialists to the environment. The tighter correlation between local climate and diversity estimates in the Cantabrian range suggests relict character of rich fens in that region, where climatic conditions have restricted local distribution of formerly more widely distributed specialists. Although there is no relevant evidence of vegetation impoverishment in that region, historical isolation has probably resulted in the existence of fragmentary plant communities. We conclude that fen vegetation may experience long-time persistence in climatically sub-optimal mountain refugia, but related plant specialists may be sensitive to climatic changes and subject to the extinction of local populations.  相似文献   

5.
Mountain systems throughout the globe are characterized by high levels of species richness and species endemism. Biodiversity, however, is not distributed evenly with altitude, but often declines from mid to high altitudes. Conversely, endemic species may be over‐represented at high altitudes. Upward elevational range shifts of mountain species have been reported in response to ongoing changes in climate, yet the reports are dominated by studies on woody species and mountains at high latitudes. We investigated spatial and temporal changes in the mountain biodiversity in the subtropical island of Taiwan, based on historical survey and resurvey data during the period 1906–2006. We found that upper altitudinal limits of mountain plant distributions have risen by ca 3.6 m yr?1 during the last century, in parallel with rising temperatures in the region. Although species, genus, and family richness decline with altitude, ca 55% of species at the highest altitudes are endemic to the island. Given the steep decline in land area with increasing elevation, these high altitude areas are disproportionately important for plant biodiversity when richness and endemism are standardized by available land area. We argue that the distributional shift that we report, in combination with the altitudinal distribution of plant diversity, is likely to pose a major threat to high mountain species of this highly biodiverse island, a threat that is becoming increasingly evident for high mountain plants throughout the globe.  相似文献   

6.
Study of the geographical variation of yellow-floweredTeucrium sect.Polium species using morphological, chemical, and cytological analyses shows that the group of North African taxa is both differentiated from the European group and homogeneous with it. It displays stable vegetative and floral characters that are common to all the taxa. The essential differences concern the indumentum structure and the habit of the plants. The diversity of environments has enhanced the expression of successive radiations of the group. The first doubtless originated in the Betic-Rif zone and in particular in the southeastern part of the Iberian Peninsula. These radiations probably first gave the groupT. aureum, now endemic in the Ibero-Provençal mountains. The species then became better differentiated in North Africa. Differentiation took place in the mountain ranges (Rif, Atlas, and Hoggar) and some Mediterranean islands (off the eastern coast of Tunisia) for the current species with narrow endemism and in desert regions (steppes and the Sahara) for those with wider endemism.  相似文献   

7.
The three sections of this paper report on i) new species, ii) new records for the Flora Zambesiaca region and for Mozambique and iii) expansion of distributions of species previously thought to be endemic to particular mountains. Specimens have been collected from three mountains in north-central Mozambique visited during a collecting programme from 2006 to 2008 investigating the conservation value of the biodiversity of currently unprotected areas. Three new species: Crotalaria namuliensis, Isoglossa namuliensis and Helixanthera schizocalyx are described. Five taxa not previously recorded from the Flora Zambesiaca region are here recorded as new records for the region and 31 taxa are listed from Mozambique for the first time, including five taxa previously thought to be Malawi mountain endemics. The number of range extensions recorded from these Mozambican mountains is evidence of the paucity of specimens collected from this part of Mozambique and shows the need for continued collection in order to clarify the distributions of this region’s rarest species.  相似文献   

8.
Aim We analyse patterns of biodiversity in the spring snail genus Bythinella, a group of highly isolated and stenotopic freshwater species. We aim to test: (1) whether there are European areas of increased diversity (i.e. ‘hotspots’), (2) whether the potential hotspots inferred show qualitative differences in biodiversity characteristics such as endemicity, distinctiveness of taxa, age of lineages or degree of fragmentation, and (3) whether these hotspots match the Pleistocene refugia of Bythinella spp. Location Europe, Asia Minor. Methods The analyses are based on genetic data from 717 Bythinella specimens sampled at 194 sites. We used haplotypes as operational units in all analyses. To test hypothesis 1, mean pairwise genetic distances between Bythinella populations within each 1° × 1° geographical grid cell sampled in Europe were calculated. Within individual mountain ranges, grid cells with high diversity were grouped with neighbouring ones and hotspots were identified based on pre‐defined criteria. Then, to test hypothesis 2, different biodiversity indices of these regions were calculated and compared. Finally, to test hypothesis 3, the spatial distribution of the identified hotspots was compared with the known Pleistocene refugia of Bythinella spp. Results Five areas showed increased levels of genetic diversity: the Massif Central/Pyrenees, the western and eastern Alps, and the western and eastern Carpathians. These regions showed qualitative differences in biodiversity, with the eastern Carpathians holding the highest number of (endemic) haplotypes, the oldest and most distinct lineages and the highest degree of fragmentation. Only three of the five detected hotspots matched previously identified Pleistocene refugia for Bythinella spp. Main conclusions The genetic diversity of Bythinella spp. is not randomly distributed throughout Europe. Some of the hotspots we identify coincide with those found in other freshwater taxa; others have not previously been reported. Thus, spring organisms may reflect a unique evolutionary history that is distinct from lentic and lotic taxa. Our findings may be useful for conservation purposes even though the species‐level taxonomy of the genus is still under discussion.  相似文献   

9.
Precise information on spatial patterns of species richness and endemic species distribution is important for effective species conservation. In the Caucasus Ecoregion such information is virtually non-existent for invertebrate taxa. Using occurrence data from a large database we calculated species distribution models with the GARP algorithm for 471 spider species to visualize the diversity distribution of spider species in this region. Overall species diversity was highest in mountain forests of the North Caucasus, east-central Georgia, the southern slopes of the eastern Great Caucasus and south-east Azerbaijan. A regression tree analysis Chi squared automatic interaction detector method revealed the mean temperature of the driest quarter and precipitation parameters to be the main environmental factors shaping these patterns. Diversity of endemic species was correlated with overall species diversity but hotspots of endemic species (10+ percent of all species) exists in high-mountain areas, suggesting post-glacial speciation events in the high mountains as the main sources of high endemism in Caucasus. Further information on the spatial distribution of species diversity of invertebrate taxa in the Caucasus Ecoregion is needed to improve conservation efforts in this biodiversity hotspot.  相似文献   

10.
Refugia play a critical role in preserving species unable to move or adapt to cope with environmental change. The role of refugia as ‘museums of diversity’ means these environments have a high conservation priority. Less well known, however, is the role that isolated and fragmented refugia can play in the generation of new diversity. Here, we examined the diversification and evolutionary history of a community of endemic invertebrates that inhabit Australian desert spring refugia. We compared the phylogenies of seven endemic groups (Haloniscus and Phreatomerus isopods, chiltoniid amphipods, Ngarawa ostracods, Trochidrobia and Fonscochlea snails and Gymnochthebius beetles) from these springs and examine the rates and timing of diversification and reconstructed the phylogeographic history of each taxon. Despite major life‐history differences among these taxa, they demonstrate remarkable similarities in their evolutionary histories. All groups have multiple lineages that extend back to a time before the formation of present‐day deserts, and significant geographic‐based diversification since adapting to a refugial habitat. The results provide further evidence that refugia act as museums of biodiversity, preserving lineages that would have otherwise gone extinct. However, we also observed that isolation in refugia corresponds with significant diversification, leading to a recently evolved, novel endemic fauna, supporting the idea that fragmented refugia provide ideal conditions for the generation of future biodiversity hotspots.  相似文献   

11.
Mountain regions are centers of biodiversity endemism at a global scale but the role of arid‐zone mountain ranges in shaping biodiversity patterns is poorly understood. Focusing on three guilds of taxa from a desert upland refugium in Australia, we sought to determine: (a) the relative extent to which climate, terrain or geological substrate predict endemism, and (b) whether patterns of endemism are complimentary across broad taxonomic guilds. We mapped regional endemism for plants, land snails, and vertebrates using combined Species Distribution Models (SDMs) for all endemic taxa (n = 82). We then modelled predictors of endemism using Generalised Additive Models (GAMs) and geology, terrain, and climate variables. We tested for the presence of inter‐ and intraguild hotspots of endemism. Many individual plant and land snail taxa were tightly linked with geology, corresponding to small distributions. Conversely, most vertebrate taxa were not constrained to specific geological substrates and occurred over larger areas. However, across all three guilds climate was the strongest predictor of regional endemism, particularly for plants wherein discrete hotspots of endemism were buffered from extreme summer temperatures. Land snail and vertebrate endemism peaked in areas with highest precipitation in the driest times of the year. Hotspots of endemism within each guild poorly predicted endemism in other guilds. We found an overarching signal that climatic gradients play a dominant role in the persistence of endemic taxa in an arid‐zone mountain range system. An association with higher rainfall and cooler temperatures indicates that continuing trends toward hotter and drier climates may lead to range contractions in this, and potentially other, arid‐zone mountain biotas. Contrasting patterns of endemism across guilds highlight the need to couple comprehensive regional planning for the protection of climate refugia, with targeted management of more localized and habitat specialist taxa.  相似文献   

12.
We determined the environmental correlates of vascular plant biodiversity in the Baetic‐Rifan region, a plant biodiversity hotspot in the western Mediterranean. A catalog of the whole flora of Andalusia and northern Morocco, the region that includes most of the Baetic‐Rifan complex, was compiled using recent comprehensive floristic catalogs. Hierarchical cluster analysis (HCA) and detrended correspondence analysis (DCA) of the different ecoregions of Andalusia and northern Morocco were conducted to determine their floristic affinities. Diversity patterns were studied further by focusing on regional endemic taxa. Endemic and nonendemic alpha diversities were regressed to several environmental variables. Finally, semi‐partial regressions on distance matrices were conducted to extract the respective contributions of climatic, altitudinal, lithological, and geographical distance matrices to beta diversity in endemic and nonendemic taxa. We found that West Rifan plant assemblages had more similarities with Andalusian ecoregions than with other nearby northern Morocco ecoregions. The endemic alpha diversity was explained relatively well by the environmental variables related to summer drought and extreme temperature values. Of all the variables, geographical distance contributed by far the most to spatial turnover in species diversity in the Baetic‐Rifan hotspot. In the Baetic range, climate was the most significant driver of nonendemic species beta diversity, while lithology and climate were the main drivers of endemic beta diversity. Despite the fact that Andalusia and northern Morocco are presently separated by the Atlantic Ocean and the Mediterranean Sea, the Baetic and Rifan mountain ranges have many floristic similarities – especially in their western ranges – due to past migration of species across the Strait of Gibraltar. Climatic variables could be shaping the spatial distribution of endemic species richness throughout the Baetic‐Rifan hotspot. Determinants of spatial turnover in biodiversity in the Baetic‐Rifan hotspot vary in importance between endemic and nonendemic species.  相似文献   

13.
BackgroundThe world is undergoing exceptional biodiversity loss. Most conservation efforts target biodiversity hotspots at large scales. Such approach overlooks small-sized local hotspots, which may be rich in endemic and highly threatened species. We explore the importance of mountain rock pools (gueltas) as local biodiversity hotspots in the Sahara-Sahel. Specifically, we considered how many vertebrates (total and endemics) use gueltas, what factors predict species richness, and which gueltas are of most priority for conservation. We expected to provide management recommendations, improve local biodiversity conservation, and simultaneously contribute with a framework for future enhancement of local communities’ economy. The identification of local hotspots of biodiversity is important for revaluating global conservation priorities.Conclusion/SignificanceGueltas are crucial for local biodiversity conservation and human activities. They require urgent management plans in Mauritania’s mountains. They could provide refugia under climate change being important for long-term conservation of Sahara-Sahel biodiversity. Given their disproportional importance in relation to their size, they are local hotspots of biodiversity deserving global attention.  相似文献   

14.
Mediterranean mountain ranges harbour highly endemic biota in islandlike habitats. Their topographic diversity offered the opportunity for mountain species to persist in refugial areas during episodes of major climatic change. We investigate the role of Quaternary climatic oscillations in shaping the demographic history and distribution ranges in the spider Harpactocrates ravastellus, endemic to the Pyrenees. Gene trees and multispecies coalescent analyses on mitochondrial and nuclear DNA sequences unveiled two distinct lineages with a hybrid zone around the northwestern area of the Catalan Pyrenees. The lineages were further supported by morphological differences. Climatic niche‐based species distribution models (SDMs) identified two lowland refugia at the western and eastern extremes of the mountain range, which would suggest secondary contact following postglacial expansion of populations from both refugia. Neutrality test and approximate Bayesian computation (ABC) analyses indicated that several local populations underwent severe bottlenecks followed by population expansions, which in combination with the deep population differentiation provided evidence for population survival during glacial periods in microrefugia across the mountain range, in addition to the main Atlantic and Mediterranean (western and eastern) refugia. This study sheds light on the complexities of Quaternary climatic oscillations in building up genetic diversity and local endemicity in the southern Europe mountain ranges.  相似文献   

15.
Summary This study demonstrates the impact of natural factors and human activities on biodiversity at gene level on a keystone Mediterranean forest ecosystem species. We monitored the within and among population gene diversity of Cedrus libani, a forest tree species of the Eastern Mediterranean mountains. We used paternally inherited chloroplast microsatellites (57 haplotypes) and bi-parentally inherited isozymes (12 loci) to estimate allelic richness, heterozygosity, and differentiation in 18 natural and 1 planted populations from Turkey and Lebanon. We showed that there is a phylogeographic structure in C. libani, and that forests from Lebanon and Turkey constitute two genetically isolated groups which probably arose from distinct refugia after the last Quaternary glacial cycle. We found extensive gene flow and relatively low differentiation in Turkey, as well as little evidence of genetic drift within populations. However, one population we analyzed, which was planted more than 20 centuries ago, and is isolated from core populations in Turkey, demonstrated extremely low genetic diversity and deserves high conservation priority. In contrast, we found low gene flow, high differentiation and severe cases of genetic drift in Lebanon. As forests there are the remnants of millennia-long extensive deforestation, all deserve high conservation priority.  相似文献   

16.
Orophilous species are often unable to escape the consequences of climate change because mountains are surrounded by unsuitable habitats. Among them, several endemic species belonging to the genus Erebia Dalman (Lepidoptera, Nymphalidae, Satyrinae) can be considered as key species to assess the risk of biodiversity loss of mountain habitats. The aim of this paper is to measure changes that have occurred in the altitudinal distribution of Erebia cassioides on the Pollino Massif (Southern Italy) during the last 37 years. Sixteen sites sampled in 1975 have been resampled after about three decades (2004, 2012). In 1975 56 % of the sampled population inhabited sites above and 44 % sites below the treeline, while in 2004 and 2012 99 % of the population were observed above the treeline. Furthermore, we observed an uphill shift of 180 m in the barycentre altitude of the species distribution and an unexpected increased density of the population above the treeline which led to a range reduction coupled to population increase of E. cassioides. This pattern contrasts with the usually observed one that couples habitat reduction to population decreasing. The reason for the observed pattern is unclear, but the implication for conservation strategies could be important if confirmed for other species. In fact, during coming decades local extinctions as a consequence of climate change might be fewer and more delayed than expected, and relict populations of cold adapted species could be preserved for a longer time span within optimal habitat refugia.  相似文献   

17.
Northwest Africa is a major hotspot of plant biodiversity, but very little is known about the Quaternary range dynamics of plant species in this region. Here we investigate the range-wide population structure and phylogeography of Atlas cedar (Cedrus atlantica), an emblematic forest tree endemic to Morocco and Algeria. We genotyped 261 individuals from 11 populations using AFLP markers. Data were analyzed using both conventional F(ST)-based techniques and Bayesian clustering. Overall population differentiation was high (F(ST) = 0.25). Two major groups of populations were identified, one distributed through the Rif and Middle Atlas mountains in Morocco and the other through the Algerian Tell Atlas and Aurès mountains as well as the Middle Atlas. Combined molecular and fossil data indicate that C. atlantica survived the Last Glacial Maximum in at least three disjunct refugia along the coast of the Mediterranean Sea, whereas the Middle Atlas, today the core of the species range, has been colonized relatively recently (<10000 yr BP). The colonization history of individual populations has left clear imprints in their present-day diversity, which may vary greatly even between nearby stands. Our study illustrates how integrating different data sources and analytical approaches can help elucidate complex range dynamics that would otherwise remain undeciphered.  相似文献   

18.
Conserving biodiversity on mountains holds particular challenges, with topographic species beta diversity being high. In turn, conserving mountain biodiversity in the heart of a biodiversity hotspot, with intense urbanization on its lower slopes, poses further challenges. We investigate here an iconic mountain at the southern tip of Africa, which is under multiple human pressures, while receiving much conservation attention. We sought here some general principles to guide conservation management of this and other similar mountains. Our focal organisms were surface-active invertebrates, as they are abundant, diverse, and environmentally sensitive at point localities. We show that vegetation structure and elevation were the most important environmental variables determining this diversity. Type of fynbos vegetation, proximity of forest to a river, aspect, and abundance of the alien Argentine ant Linepithema humile, had no significant influence. Suburban woodland species richness and abundance had a non-significant difference to that of natural forest. Fynbos had high species beta diversity of invertebrates, suggesting that large areas of this dominant vegetation type should be conserved. However, many specialist and highly local endemic species were in forest, highlighting the irreplaceability of forest habitats. Such a mountain, with its complex topography, requires total protection, as there is no room for loss of any part of the mountain. We emphasize that, while the upper slope and summit are well protected, the lower slopes are in need of urgent attention, a situation which mirrors that in Europe.  相似文献   

19.
The flora of California, a global biodiversity hotspot, includes 2387 endemic plant taxa. With anticipated climate change, we project that up to 66% will experience >80% reductions in range size within a century. These results are comparable with other studies of fewer species or just samples of a region's endemics. Projected reductions depend on the magnitude of future emissions and on the ability of species to disperse from their current locations. California's varied terrain could cause species to move in very different directions, breaking up present-day floras. However, our projections also identify regions where species undergoing severe range reductions may persist. Protecting these potential future refugia and facilitating species dispersal will be essential to maintain biodiversity in the face of climate change.  相似文献   

20.
As the mountains in temperate regions have been hypothesized as refugia for boreal and temperate plants during the Last Glacial Maximum, one would expect high within-population genetic variation and low or moderate among-population differentiation for those species occurring there. We selected Forsythia ovata and Forsythia saxatilis, endemic to limestone mountains of Korea, to test the scenario that limestone ranges would also have acted as refugia. We undertook a population genetic analysis using 14 putative allozyme loci of the two species and the widely cultivated Forsythia koreana. We found relatively high levels of genetic diversity and low to moderate among-population differentiation in F. ovata and F. saxatilis, which are consistent with the proposed scenario. Allozyme data revealed that F. ovata and F. saxatilis are likely conspecific. As many populations of F. ovata and F. saxatilis have experienced dramatic decreases in their size, a comprehensive conservation program is urgently needed.  相似文献   

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