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1.
Mexico is considered an exceptional biogeographic area with a varied endemic flora, however spatial phylogenetic measures of biodiversity have not yet been estimated to understand how its flora assembled to form the current vegetation. Patterns of species richness, endemism, phylogenetic diversity, phylogenetic endemism and centers of neo‐ and paleo‐endemism were determined to examine differences and congruence among these measures, and their implications for conservation. Of 24 360 vascular plant species 10 235 (42%) are endemic. Areas of endemism and phylogenetic endemism were associated with dry forests in zones of topographic complexity in mountain systems, in deserts, and in isolated xeric vegetation. Every single locality where seasonally tropical dry forests have been reported in Mexico was identified as an area of endemism. Significant phylogenetic diversity was the most restricted and occurred in the Trans‐Mexican Volcanic Belt and in the Sierra de Chiapas. Notably, the highest degree of phylogenetic clustering comprising neo‐, paleo‐, and super‐endemism was identified in southernmost Mexico. Most vascular plant lineages diverged in the Miocene (5–20 mya) when arid environments expanded across the world. The location of Mexico between two very large landmasses and the fact that more than fifty percent of its surface is arid favored the establishment of tropical lineages adapted to extreme seasonality and aridity. These lineages were able to migrate from both North and South America across Central America presumably during the Miocene and to diversify, illustrating the signature of the flora of Mexico of areas of endemism with a mixture of neo‐ and paleo‐endemism.  相似文献   

2.
The flora of China is well known for its high diversity and endemism. Identifying centers of endemism and designating conservation priorities are essential goals for biodiversity studies.However, there is no comprehensive study from a rigorous phylogenetic perspective to understand patterns of diversity and endemism and to guide biodiversity conservation in China. We conducted a spatial phylogenetic analysis of the Chinese angiosperm flora at the generic level to identify centers of neo-and pale...  相似文献   

3.
The Western Ghats (WG) mountain chain in peninsular India is a global biodiversity hotspot, one in which patterns of phylogenetic diversity and endemism remain to be documented across taxa. We used a well‐characterized community of ancient soil predatory arthropods from the WG to understand diversity gradients, identify hotspots of endemism and conservation importance, and highlight poorly studied areas with unique biodiversity. We compiled an occurrence dataset for 19 species of scolopendrid centipedes, which was used to predict areas of habitat suitability using bioclimatic and geomorphological variables in Maxent. We used predicted distributions and a time‐calibrated species phylogeny to calculate taxonomic and phylogenetic indices of diversity, endemism, and turnover. We observed a decreasing latitudinal gradient in taxonomic and phylogenetic diversity in the WG, which supports expectations from the latitudinal diversity gradient. The southern WG had the highest phylogenetic diversity and endemism, and was represented by lineages with long branch lengths as observed from relative phylogenetic diversity/endemism. These results indicate the persistence of lineages over evolutionary time in the southern WG and are consistent with predictions from the southern WG refuge hypothesis. The northern WG, despite having low phylogenetic diversity, had high values of phylogenetic endemism represented by distinct lineages as inferred from relative phylogenetic endemism. The distinct endemic lineages in this subregion might be adapted to life in lateritic plateaus characterized by poor soil conditions and high seasonality. Sites across an important biogeographic break, the Palghat Gap, broadly grouped separately in comparisons of species turnover along the WG. The southern WG and Nilgiris, adjoining the Palghat Gap, harbor unique centipede communities, where the causal role of climate or dispersal barriers in shaping diversity remains to be investigated. Our results highlight the need to use phylogeny and distribution data while assessing diversity and endemism patterns in the WG.  相似文献   

4.
Factors driving the spatial configuration of centres of endemism have long been a topic of broad interest and debate. Due to different eco-evolutionary processes, these highly biodiverse areas may harbour different amounts of ancient and recently diverged organisms (paleo- and neo-endemism, respectively). Patterns of endemism still need to be measured at distinct phylogenetic levels for most clades and, consequently, little is known about the distribution, the age and the causes of such patterns. Here we tested for the presence of centres with high phylogenetic endemism (PE) in the highly diverse Neotropical snakes, testing the age of these patterns (paleo- or neo-endemism), and the presence of PE centres with distinct phylogenetic composition. We then tested whether PE is predicted by topography, by climate (seasonality, stability, buffering and relictualness), or biome size. We found that most areas of high PE for Neotropical snakes present a combination of both ancient and recently diverged diversity, which is distributed mostly in the Caribbean region, Central America, the Andes, the Atlantic Forest and on scattered highlands in central Brazil. Turnover of lineages is higher across Central America, resulting in more phylogenetically distinct PE centres compared to South America, which presents a more phylogenetically uniform snake fauna. Finally, we found that elevational range (topographic roughness) is the main predictor of PE, especially for paleo-endemism, whereas low paleo-endemism levels coincide with areas of high climatic seasonality. Our study highlights the importance of mountain systems to both ancient and recent narrowly distributed diversity. Mountains are both museums and cradles of snake diversity in the Neotropics, which has important implications for conservation in this region.  相似文献   

5.
We present a new, broadly applicable measure of the spatial restriction of phylogenetic diversity, termed phylogenetic endemism (PE). PE combines the widely used phylogenetic diversity and weighted endemism measures to identify areas where substantial components of phylogenetic diversity are restricted. Such areas are likely to be of considerable importance for conservation. PE has a number of desirable properties not combined in previous approaches. It assesses endemism consistently, independent of taxonomic status or level, and independent of previously defined political or biological regions. The results can be directly compared between areas because they are based on equivalent spatial units. PE builds on previous phylogenetic analyses of endemism, but provides a more general solution for mapping endemism of lineages. We illustrate the broad applicability of PE using examples of Australian organisms having contrasting life histories: pea-flowered shrubs of the genus Daviesia (Fabaceae) and the Australian species of the Australo-Papuan tree frog radiation within the family Hylidae.  相似文献   

6.
The karst landform in southern China is renowned for its high levels of species diversity and endemism. Globally, karst ecosystems are under threat from unsustainable anthropogenic disturbance and climate changes and are among the most threatened ecosystems worldwide. In this study, we used the typical karst endemic genus in southern China, Primulina Hance, as a model to identify areas within the karst landform with high diversity and to investigate congruence between phylogenetic and species‐based measures of diversity. Using phylogenetic information and species distribution data, we measured geographical patterns of diversity with four metrics: species richness (SR), corrected weighted endemism (CWE), phylogenetic diversity (PD), and phylogenetic endemism (PE). Our results revealed a high spatial congruence among SR, PD, and PE, with hotspot areas identified in the Nanling Mountains (i.e., north Guangdong and northeast Guangxi) and southeast Yungui Plateau (i.e., north and southwest Guangxi), whereas the hotspots of CWE are comparatively uniform throughout the geographic extent. The categorical analysis of neo‐ and paleoendemism identified a pattern of mixed neo‐ and paleoendemism in numerous grid cells, suggesting that karst areas in southern China have acted as both “museums” and “cradles” of plant evolution. Conservation gap analysis of hotspots revealed that the majority of prioritized hotspots (>90%) of the genus are outside of protected areas, therefore indicating the limited effectiveness of national nature reserves for the karst flora. Overall, our results suggest that the karst flora merits more conservation attention and SR can be an effective surrogate to capture PD in conservation planning.  相似文献   

7.
Identifying geographical areas with the greatest representation of the tree of life is an important goal for the management and conservation of biodiversity. While there are methods available for using a single phylogenetic tree to assess spatial patterns of biodiversity, there has been limited exploration of how separate phylogenies from multiple taxonomic groups can be used jointly to map diversity and endemism. Here, we demonstrate how to apply different phylogenetic approaches to assess biodiversity across multiple taxonomic groups. We map spatial patterns of phylogenetic diversity/endemism to identify concordant areas with the greatest representation of biodiversity across multiple taxa and demonstrate the approach by applying it to the Murray–Darling basin region of southeastern Australia. The areas with significant centers of phylogenetic diversity and endemism were distributed differently for the five taxonomic groups studied (plant genera, fish, tree frogs, acacias, and eucalypts); no strong shared patterns across all five groups emerged. However, congruence was apparent between some groups in some parts of the basin. The northern region of the basin emerges from the analysis as a priority area for future conservation initiatives focused on eucalypts and tree frogs. The southern region is particularly important for conservation of the evolutionary heritage of plants and fishes.  相似文献   

8.
Cladistic biogeography of the Mexican transition zone   总被引:6,自引:2,他引:4  
Biogeographic relationships among nine montane areas of endemism across the transition zone between North and South America are analysed cladistically based on phylogenetic hypotheses of thirty‐three resident monophyletic taxa of insects, fish, reptiles, and plants. Areas of endemism include the Arizona mountains (AZ), Sonoran Desert (SD), Sierra Madre Occidental (OCC), southern Sierra Madre Occidental (SOC), Sierra Madre Oriental (ORI), Sierra Transvolcanica (TRAN), Sierra Madre del Sur (SUR), Chiapan‐Guatemalan Highlands (CGH), and Talamancan Cordillera (TC). Area relationships are summarized using Brooks Parsimony Analysis and Assumption 0, with the former resulting in more defensible biogeographic hypotheses. Areas of endemism are dividable into two monophyletic groups; a northern group including AZ, SD, OCC, and ORI, and a southern group consisting of TC, CGH, TRAN, SUR, and the isolated southern regions of the Sierra Madre Occidental (SOC). The northern set of areas are characterized by recent, probably Pleistocene, isolation and prevalent widespread species, whereas the southerly areas probably diverged after Pliocene closure of the Panamanian isthmus. The southern areas are redundantly represented on many of the taxon‐area cladograms by endemic species, indicative of much higher levels of endemism in the Sierra Transvolcanica and further south. Use of a general area cladogram in such a transition zone permits explicit exploration of biogeographic patterns and establishes a predictive framework for taxonomy and conservation prioritization.  相似文献   

9.
Analyses of richness and endemism of Cyatheales (tree ferns) in tropical America were performed and evidence of a diversity gradient is presented. For this, the occurrence ranges of 239 species were plotted into a 5° × 5° grid-cell map and then analyzed using species richness and endemism indices. Here we show that species richness and endemism are not distributed randomly over the landscape, but do aggregate into defined regions of high diversity in tropical America: the northern Andes, lower Central America, upper Central America and Mexico, the Guyana Highlands, southeastern Brazil, and the Antilles. These distributional patterns are congruent with the geographical distribution of cloud forest, which in turn is determined by topography, high humidity, and persistent cloud immersion. The mountain regions of tropical America, especially the cloud forests, harbour most of the species of American Cyatheales and have high levels of habitat loss and climatic fragility. Conservation policies for Cyatheales are centred on the local use and trade of many tree fern species, but none such policies focus on cloud forest habitat loss. This makes tree ferns a critically endangered group of plants. In the face of the current environmental crisis and global climate change, the presence of Cyatheales in these regions sounds the alarm on their conservation priorities.  相似文献   

10.
Aim To use the method of parsimony analysis of endemism to identify areas of endemism for passerine birds in the Atlantic Forest, South America, and to compare the locations of these areas with areas previously identified for birds as well as other taxa. Location The Atlantic Forest, eastern South America. Methods We analysed a matrix composed of the presence (1) or absence (0) of 140 endemic species in 24 quadrats of 1 × 1 degree distributed along the Atlantic Forest to find the most parsimonious area cladogram. Results Fourteen most parsimonious cladograms were found and then summarized in a single consensus tree. Four areas of endemism were identified: Pernambuco, Central Bahia, Coastal Bahia, and Serra do Mar. Main conclusions Avian areas of endemism in the Atlantic Forest have significant generality, as they are highly nonrandom and congruent with those of other groups of organisms. A first hypothesis about the historical relationships among the four areas of avian endemism in the Atlantic Forest is delineated. There is a basal dichotomy among areas of endemism in the Atlantic Forest, with Pernambuco forming a northern cluster and Coastal Bahia, Central Bahia and Serra do Mar comprising a southern cluster. Within the southern cluster, Central Bahia and Serra do Mar are more closely related to each other than to Coastal Bahia.  相似文献   

11.
Using complementary metrics to evaluate phylogenetic diversity can facilitate the delimitation of floristic units and conservation priority areas. In this study, we describe the spatial patterns of phylogenetic alpha and beta diversity, phylogenetic endemism, and evolutionary distinctiveness of the hyperdiverse Ecuador Amazon forests and define priority areas for conservation. We established a network of 62 one‐hectare plots in terra firme forests of Ecuadorian Amazon. In these plots, we tagged, collected, and identified every single adult tree with dbh ≥10 cm. These data were combined with a regional community phylogenetic tree to calculate different phylogenetic diversity (PD) metrics in order to create spatial models. We used Loess regression to estimate the spatial variation of taxonomic and phylogenetic beta diversity as well as phylogenetic endemism and evolutionary distinctiveness. We found evidence for the definition of three floristic districts in the Ecuadorian Amazon, supported by both taxonomic and phylogenetic diversity data. Areas with high levels of phylogenetic endemism and evolutionary distinctiveness in Ecuadorian Amazon forests are unprotected. Furthermore, these areas are severely threatened by proposed plans of oil and mining extraction at large scales and should be prioritized in conservation planning for this region.  相似文献   

12.
Geospatial patterns in the distribution of regional biodiversity reflect the composite processes that underpin evolution: speciation, dispersal and extinction. The spatial distribution and phylogeny of a globally widespread and species rich bird family (Rallidae) were used to help assess the role of large‐scale biogeographical processes in diversity and diversification. Here, we examine how different geostatistical diversity metrics enhance our understanding of species distribution by linking occurrence records of rail species to corresponding species level phylogeny. Tropical regions and temperate zones contained a large proportion of rail species richness and phylogenetic diversity whilst small islands in Australian, Oceanian and Oriental regions held the highest weighted and phylogenetic endemism. Our results suggest that habitat connectivity and dispersal were important ecological features in rail evolution and distribution. Spatial isolation was a significant driver of diversification where islands in Oceania were centres of neo‐endemism with recent multiple and independent speciation events and could be considered as nurseries of biodiversity. Palaeo‐endemism was mostly associated with older stable regions, so despite extensive long distance range shifting these areas retain their own ancient and distinct character. Madagascar was the major area of palaeo‐endemism associated with the oldest rail lineages and could be considered a museum of rail diversity. This implies a mixture of processes determine the current distribution and diversity of rail clades with some areas dominated by recent ‘in situ’ speciation while others harbour old diversity with ecological traits that have stood the test of time.  相似文献   

13.
Since the 19th Century, two regions have been recognized for North American mammals, which overlap in Mexico. The Nearctic region corresponds to the northern areas and the Neotropical region corresponds to the southern ones. There are no recent regionalizations for these regions under the criterion of endemism. In the present study, we integrate two methods to regionalize North America, using species distribution models of mammals: endemicity analysis (EA) and parsimony analysis of endemicity (PAE). EA was used to obtain areas of endemism and PAE was used to hierarchize them. We found 76 consensus areas from 329 sets classified in 146 cladograms, and the strict consensus cladogram shows a basal polytomy with 14 areas and 16 clades. The final regionalization recognizes two regions (Nearctic and Neotropical) and a transition zone (Mexican Transition Zone), six subregions (Canadian, Alleghanian, Californian‐Rocky Mountain, Pacific Central America, Mexican Gulf‐Central America, and Central America), two dominions (Californian and Rocky Mountain), and 23 provinces. Our analysis show that North America is probably more complex than previously assumed. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 485–499.  相似文献   

14.
North America is a large continent with extensive climatic, geological, soil, and biological diversity. As biota faces threat from habitat destruction and climate change, making a quantitative assessment of biodiversity becomes critically important. Rapid digitization of plant specimen records and accumulation of DNA sequence data enable a much‐needed broad synthesis of species occurrences with phylogenetic data. In this study, the first such synthesis of a flora from such a large and diverse part of the world is attempted, all seed plants from the North American continent (here defined to include Canada, United States, and Mexico), with a focus on examining phylogenetic diversity and endemism. We collected digitized plant specimen records and chose a coarse grain for analysis, recognizing that this grain is currently necessary for reasonable completeness per sampling unit. We found that raw richness and endemism patterns largely support previous hypotheses of biodiversity hotspots. The application of phylogenetic metrics and a randomization test revealed novel results, including a significant phylogenetic clustering across the continent, a striking east–west geographical difference in the distribution of branch lengths, and the discovery of centers of neo‐ and paleoendemism in Mexico, the southwestern USA, and the southeastern USA. Finally, our examination of phylogenetic beta diversity provides a new approach to compare centers of endemism. We discuss the empirical challenges of working at the continental scale and the need for more sampling across large parts of the continent, for both DNA data for terminal taxa and spatial data for poorly understood regions, to confirm and extend these results.  相似文献   

15.
Phenotypic and genetic variation are present in all species, but lineages differ in how variation is partitioned among populations. Examining phenotypic clustering and genetic structure within a phylogeographic framework can clarify which biological processes have contributed to extant biodiversity in a given lineage. Here, we investigate genetic and phenotypic variation among populations and subspecies within a Neotropical songbird complex, the White‐collared Seedeater (Sporophila torqueola) of Central America and Mexico. We combine measurements of morphology and plumage patterning with thousands of nuclear loci derived from ultraconserved elements (UCEs) and mitochondrial DNA to evaluate population differentiation. We find deep levels of molecular divergence between two S. torqueola lineages that are phenotypically diagnosable: One corresponds to S. t. torqueola along the Pacific coast of Mexico, and the other includes S. t. morelleti and S. t. sharpei from the Gulf Coast of Mexico and Central America. Surprisingly, these two lineages are strongly differentiated in both nuclear and mitochondrial markers, and each is more closely related to other Sporophila species than to one another. We infer low levels of gene flow between these two groups based on demographic models, suggesting multiple independent evolutionary lineages within S. torqueola have been obscured by coarse‐scale similarity in plumage patterning. These findings improve our understanding of the biogeographic history of this lineage, which includes multiple dispersal events out of South America and across the Isthmus of Tehuantepec into Mesoamerica. Finally, the phenotypic and genetic distinctiveness of the range‐restricted S. t. torqueola highlights the Pacific Coast of Mexico as an important region of endemism and conservation priority.  相似文献   

16.
We illustrate the use of Faith's 'Phylogenetic Diversity' measure to compare the phylogeographic structure of two bird species with patterns of avian endemism across six mountains in Cameroon and Equatorial Guinea. The Mountain Greenbul and Cameroon Blue-headed Sunbird showed phylogeographic patterns that together defined three biogeographic regions: Bioko, Mt. Cameroon, and the northern mountains of Cameroon. In contrast, the distributions of endemic species were largely a function of geographical distance, with close mountains sharing more endemic species than distant mountains. Moreover, for both species, populations on Mt. Cameroon were distinctive with respect to the ecologically relevant character bill size. Our results, while preliminary, illustrate the utility of a comparative approach for identifying geographical regions that harbour evolutionarily distinct populations and caution against using only the distributional patterns of endemics to prioritize regions for conservation. Results show that patterns of endemism may not be concordant with patterns of phylogenetic diversity nor morphological variation in a character important in fitness. While incorporation of additional species from unrelated taxa will be necessary to draw definitive conclusions about evolutionarily distinct regions, our preliminary results suggest a conservation approach for the Afromontane region of the Gulf of Guinea that would: (i) emphasize protection of both Bioko and Mt. Cameroon, thereby maximizing preservation of within-species phylogenetic and morphologic diversity; (ii) emphasize protection within the northern mountains to further conserve intraspecific phylogenetic diversity and maximize protection of endemic species.  相似文献   

17.
18.
Aim The Southern African orchid flora is taxonomically well known, but the biogeographical and diversity patterns have not yet been analysed. In particular, we want to establish whether (a) it is, like the Southern African flora in general, more diverse than would be expected from its latitude and area; (b) it is an African flora, or whether it contains palaeoendemic relicts of a Gondwanan orchid flora; (c) the diversity and endemism in the orchid flora is concentrated in particular biomes and habitat types; and (d) the patterns of endemism in the flora can be accounted for by current environmental parameters, or whether we need to invoke historical explanations. Location Southern Africa. Methods We used the recent floristic account of the Southern African orchids, in conjunction with a data base of over 14,642 herbarium records, to assign the species and subspecies of Southern African orchids to biomes, habitats, and clades. We explored the relationship between the number and endemism of entities (species, subspecies and varieties) and the biomes and habitats. We compared the richness of this flora with that of 31 other regions from all continents and latitudes, to establish whether the Southern African orchid flora is richer or poorer than expected. We assigned the Southern African orchid species to 16 monophyletic clades and mapped the global distribution of these clades to establish the continental affinities of the flora. Main conclusions The Southern African orchid flora is not any more diverse than could be expected from its latitude or area, while the two tropical African floras included were less diverse than expected. Latitude is an excellent predictor of regional orchid species richness; this might indicate that available habitat is more important for orchid diversity than gross area available, since latitude is probably correlated with the extent of suitable habitat. The Southern African orchid flora is clearly an African flora, since all clades are also found in tropical Africa, while many of them are absent from the Americas or Asia. Conversely, while most African orchid clades are also found in Southern Africa, both the Americas and Asia contain many clades absent from Africa. The distribution of orchid entities among the biomes in Southern Africa is very uneven, with two of the seven biomes totally devoid of orchids. Habitats and biomes that have no equivalent in tropical Africa are high in endemism, and habitats and biomes which are also well developed in tropical Africa are low in endemism. Endemism appears largely explained in terms of modern habitats. However, two patterns (the high endemism in the Succulent Karoo and the lack of endemism in the southern Cape among epiphytic orchids) may also be explained in terms of Quaternary climatic changes.  相似文献   

19.
Phylogeographic endemism, the degree to which the history of recently evolved lineages is spatially restricted, reflects fundamental evolutionary processes such as cryptic divergence, adaptation and biological responses to environmental heterogeneity. Attempts to explain the extraordinary diversity of the tropics, which often includes deep phylogeographic structure, frequently invoke interactions of climate variability across space, time and topography. To evaluate historical versus contemporary drivers of phylogeographic endemism in a tropical system, we analyse the effects of current and past climatic variation on the genetic diversity of 25 vertebrates in the Brazilian Atlantic rainforest. We identify two divergent bioclimatic domains within the forest and high turnover around the Rio Doce. Independent modelling of these domains demonstrates that endemism patterns are subject to different climatic drivers. Past climate dynamics, specifically areas of relative stability, predict phylogeographic endemism in the north. Conversely, contemporary climatic heterogeneity better explains endemism in the south. These results accord with recent speleothem and fossil pollen studies, suggesting that climatic variability through the last 250 kyr impacted the northern and the southern forests differently. Incorporating sub-regional differences in climate dynamics will enhance our ability to understand those processes shaping high phylogeographic and species endemism, in the Neotropics and beyond.  相似文献   

20.
Abstract Identification of biodiversity hotspots is essential to conservation strategies aimed at minimizing the possibility of losing half of the world's species in the next 50 years. The aims of the present study were: (i) to locate and designate zones of endemism in the temperate forest of South America; and (ii) to compare the distribution of these areas with the distribution of existing protected areas in this habitat type. Endemism areas were determined by using parsimonious analysis of endemism, which identified zones of endemism on the basis of sets of endemic species that were restricted to two or more study areas. We used distribution information for five unrelated taxa (ferns, trees, reptiles, birds and mammals) to provide more reliable results and patterns than would work with only a single taxon or related taxa. The northern part of this region has high endemism for all of the taxa considered in this study. We demonstrate that although the temperate forest of South America has more than 30% of its area under some type of protection, correlation between protected areas and the areas of endemism is remarkably low. In fact, less than 10% of protected areas are situated in areas that have the greatest value for conservation (i.e. high endemism). Under the current strategy, biodiversity within South America's temperate forest is in danger despite the large amount of protected area for this forest type.  相似文献   

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