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1.
Abstract

This study was conducted to identify areas of endemism for Acantholimon species using parsimony analysis of endemicity (PAE) and to detect endemic species richness of the genus in the region. The results obtained from the two methods used in this study were used in determining the priorities for the conservation of Acantholimon species in Iran. The distribution database of 62 endemic species belonging to this genus was formed by 1250 georeferenced observations in Iran. The study area was divided into 1?×1? grids of operative geographical units (OGUs) and the species?×?area matrix including presence/absence data was created. The endemic species richness was calculated using circular neighborhood with a radius of 50?km in 10?×?10?km2 raster cells using DIVA-GIS software. The results of PAE analysis have shown four areas of endemism (AOEs) in Iran. AOE1: including Alborz and Zagros mountains, the mountains of central Iran. AOE2 and AOE3 are located in Khorassan subregion and AOE4 contains parts of western Iran. The map of endemic species richness indicated that the highest number of endemic species occurs in central Alborz region as well as Kerman, Chahar-Mahal and Bakhtiari, and Isfahan provinces.  相似文献   

2.
Aim Floristic blocks and areas of endemism resulting from a parsimony analysis of endemicity (PAE) using raw floristic data versus data generated from distributional modelling for 130 species in the genus Senecio Tourn. ex L. distributed in the Mediterranean‐type climate area of Central Chile were compared, and the results were used to identify conservation priorities for the flora of the region. Location Central Chile, between 30° and 38° S. Methods Using herbarium records, a species × area matrix consisting of presence/absence data was constructed from a 0.5° × 0.5° grid. Distributional modelling techniques incorporating vegetation formations, elevation and the contagion index were used to interpolate floristic composition of poorly known areas. Parsimony analysis of endemicity was used to identify floristic blocks and areas of endemism. Results Using the number of most parsimonious trees as an index, distributional modelling greatly optimized the results of the PAE analysis. Three floristic blocks and four areas of endemism were suggested based on the PAE results using potential distribution data not incorporating the contagion index, while four blocks and two areas of endemism were suggested from the PAE results using potential distribution data incorporating the contagion index. Floristic blocks for the northern coast, southern Andes, and northern/central Andes were found, with some blocks showing divisions within them representing distinct geographic subunits. Major breaks between and within floristic blocks were identified at 32.5°–33° S and 34.5°–35° S. Main conclusions The floristic blocks identified with the distributional modelling and PAE correspond well to results from some previous studies and support hypothesized biogeographic divisions within Central Chile. The results were similar to those obtained from parallel analysis of the entire tree flora of Central Chile. The vegetative formation‐based distributional modelling produced robust and reproducible results when used along with PAE, especially when the contagion index was incorporated, and is a useful technique for area classification. The results demonstrate the utility of Senecio as an indicator genus for biogeography and conservation in southern South America.  相似文献   

3.
Aim We present a biogeographical analysis of the areas of endemism and areas of diversification in the Muscidae. This analysis searched for geographical patterns in the Muscidae to reconstruct elements of the evolutionary biogeographical history of this insect family. Location Andean and Neotropical regions. Method We constructed a geographic database of 728 species from the literature and museum specimens. Areas of endemism were established by parsimony analysis of endemicity (PAE) based on grids of two different sizes: 5° (550 × 550 km) and 2° (220 × 220 km). Areas of diversification were delimited by track analysis that also included phylogenetic information. This process was independently applied to 11 genera. For each genus, we plotted generalized tracks generated by sister species on a map. When these generalized tracks supported inter‐generic nodes they were manually contoured and inferred to be areas of diversification for the Muscidae. Results Thirteen endemic areas were found using the 5° grid, and eight endemic areas resulted from the 2° grid. Ten areas were in agreement with previous studies, and 11 were new. Amazonian and Atlantic areas of diversification agreed with previous areas for the genus Polietina, and new areas of diversification were found in Panama and in central Chile. Main conclusions Six spatial patterns in the Muscidae were identified: (1) areas of endemism in both Pampa and Puna provinces were established with species whose distributions had not previously been analysed; (2) a new area of endemism was established in extreme southern South America, in Tierra del Fuego; (3) two new areas of diversification, which include Panama and central Chile, were identified; (4) a spatial association was identified between the separation of Chiloe Island from the continent and the diversification in Andean species; (5) a north–south track axis and latitudinal node intervals were identified, interpreted as spatial responses to glaciation or glacial retreat in the Andes; and (6) a spatial coincidence of areas of endemism, of diversification and high species richness in the Muscidae was discovered. The analysis of a complete database and the recognition of areas of diversification are extremely important in elucidating novel biogeographical patterns, which will in turn contribute to a better understanding of the geographical patterns of evolution in the Muscidae.  相似文献   

4.
Aim  The study aimed to identify areas of endemism for aphids in the Qinghai-Tibetan Plateau and the Himalayas (QTPH), and to test congruence between patterns of endemism and patterns of overall species richness identified in a previous study.
Location  The QTPH.
Methods  A distribution data base of 326 endemic aphids in the QTPH was compiled. The study area was divided into a grid of 2°× 2° operative geographical units. Parsimony analysis of endemicity (PAE) was used to identify areas of endemism, and the diversity patterns of endemic species were then mapped using GIS.
Results  We identified 326 endemic species belonging to 138 genera within Adelgidae and 14 subfamilies of Aphididae. Five areas of endemism were found using PAE analysis: the eastern Himalayas, the western Himalayas, north-western Yunnan, southern Tibet and the eastern QTPH. Maps of patterns of endemism identified four major centres for endemic aphids, namely the western Himalayas, the eastern Himalayas (or Sikkim-Assam Himalayas), north-western Hengduan Mountains and the mountains of southern Gansu Province, and three minor centres, southern Tibet, south-eastern Tibet and the eastern Qinghai Province in the north-eastern QTPH.
Main conclusions  Our study identifies major centres of aphid endemism. Furthermore, there is a noticeable congruence between patterns of endemism and patterns of species richness. The patterns of endemism were most likely influenced by the recent uplift of the QTPH.  相似文献   

5.
Endemic taxa are those restricted to a specific area, and could bedefined as the exclusive biodiversity of a region. An area of endemismcontains taxa found nowhere else and could be catalogued as irreplaceable and of highpriority for conservation. proposed the parsimony analysis of endemicity (PAE) as a tool to detect areas ofendemism. PAE, a method of historical biogeography, is analogous to cladisticmethods used in phylogenetics analysis, and unites areas (taxa in cladistics)based on their shared species (characters in cladistics) according to the mostparsimonious solution. In this paper we determined with PAE, prioritary areasfor conservation on the basis of concentrations of endemic species in the aridregion of Antofagasta, northern Chile, and compared the results with theirrepresentation in the current Chilean National Parks and Reserves System. Wefound two areas suggested as priorities, one located in the north Andean zone ofthe region, and another at the coast. The area with the higher biodiversity andconcentration of endemics was that located at the coast. However, coastalecosystems are currently under-represented in the Chilean National Parks andReserves System. The establishment of a new protected area in the coastal zoneof the region of Antofagasta is currently under consideration, coinciding withthe area suggested with PAE as priority. This new area would not only allowconserving species with evident problems of conservation, but also preserving anarea where higher levels of endemism exist.  相似文献   

6.
Indigenous palm species of Peru are listed with data on their distribution patterns, ecology, frequency, density in the ecosystems, and conservation status. Peruvian palm flora includes 140 native species in 34 genera with the following distribution patterns: strictly Andean (17), Andean and Subandean (3), strictly Subandean (19), Subandean and Amazonian (20), strictly Amazonian (78), Amazonian and South peripheral (2), South peripheral (1). About 43% of the species occur at very low or low frequency in the country and about 9% are insufficiently known in situ for their conservation status to be defined. There are no Extinct species. Sixteen of the 17 strictly Andean palms are threatened species; 3 of them are Endangered, while only 5 strictly Subandean, 3 Subandean-Amazonian, and 4 strictly Amazonian palms are in these categories.  相似文献   

7.
Aim The study aimed to establish areas of endemism and distribution patterns for Neotropical species of the genus Piper in the Neotropical and Andean regions by means of parsimony analysis of endemicity (PAE) and track‐compatibility analysis. Location The study area includes the Neotropical region and the Northern Andean region (Páramo‐Punan subregion). Methods We used distribution information from herbarium specimens and recent monographic revisions for 1152 species of Piper from the Neotropics. First, a PAE was attempted in order to delimit the areas of endemism. Second, we performed a track‐compatibility analysis to establish distribution patterns for Neotropical species of Piper. Terminology for grouping Piper is based on recent phylogenetic analyses. Results The PAE yielded 104 small endemic areas for the genus Piper, 80 of which are in the Caribbean, Amazonian and Paranensis subregions of the Neotropical region, and 24 in the Páramo‐Punan subregion of the Andean region. Track‐compatibility analysis revealed 26 generalized tracks, one in the Páramo‐Punan subregion (Andean region), 19 in the Neotropical region, and six connecting the Andean and Neotropical regions. Both the generalized tracks and endemic areas indicate that distribution of Piper species is restricted to forest areas in the Andes, Amazonia, Chocó, Central America, the Guayana Shield and the Brazilian Atlantic coast. Main conclusions Piper should not be considered an Andean‐centred group as it represents two large species components with distributions centred in the Amazonian and Andean regions. Furthermore, areas of greater species richness and/or endemism are restricted to lowland habitats belonging to the Neotropical region. The distribution patterns of Neotropical species of Piper could be explained by recent events in the Neotropical region, as is the case for the track connecting Chocó and Central America, where most of the species rich groups of the genus are found. Two kinds of event could explain the biogeography of a large part of the Piper taxa with Andean–Amazonian distribution: pre‐Andean and post‐Andean events.  相似文献   

8.
9.
Historical biogeography of South American freshwater fishes   总被引:4,自引:0,他引:4  
Aim To investigate biogeographical patterns of the obligate freshwater fish order Characiformes. Location South America. Methods Parsimony analysis of endemicity, likelihood analysis of congruent geographical distribution, and partition Bremer support were used. Results Areas of endemism are deduced from parsimony analysis of endemicity, and putative dispersal routes from a separate analysis of discordant patterns of distribution. Main conclusions Our results demonstrate the occurrence of 11 major areas of endemism and support a preferential eastern–western differentiation of the characiforms in the Amazonian region, contrasting with the southern–northern differentiation of terrestrial organisms. The areas of endemism identified seem to be deeply influenced by the distribution of the emerged land during the 100‐m marine highstand that occurred during the late Miocene and allow us to hypothesize the existence of eight aquatic freshwater refuges at that time. The raw distribution of non‐endemic species supports nine patterns of species distribution across the 11 areas of endemism, two of which support a southern–northern differentiation in the eastern part of the Amazon. This result shows that the main channel of the Amazon limited dispersal between tributaries from each bank of the river. The levels of endemism further demonstrate that the aquatic freshwater refuges promoted allopatric speciation and later allowed the colonization of the lowlands. By contrast, the biogeographical pattern found in the western part of the Amazon is identified as a result of the Miocene Andean foreland dynamic and the uplift of the palaeoarches that promoted allopatric divergence across several sedimentary basins by the establishment of disconnected floodplains. The assessment of conflicting species distributions also shows the presence of seven putative dispersal routes between the Amazon, Orinoco and Paraná rivers. Our findings suggest that, rather than there being a single predominant process, the establishment of the modern South American freshwater fish biotas is the result of an interaction between marine incursions, uplift of the palaeoarches, and historical connections allowing cross‐drainage dispersal.  相似文献   

10.
Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical classifications for Colombian páramos have been based on subjective assessments of species distributions. However, a detailed floristic analysis highlighting affinities between páramo regions in Colombia has not yet been proposed. The aim of this study is to provide an analytical scenario for the patterns of regional plant diversity in a hierarchical framework based on the biogeographical history of the páramos, based on 30 localities of the Colombian páramos. Parsimony analysis of endemicity (PAE) and Jaccard similarity indices were applied to a presence/absence data matrix of páramo angiosperm species. Altitudinal distribution of species was used to determine the percentage of the páramo flora endemic to this ecosystem. Genera are shared among páramos, whereas species composition is highly endemic. 86% of the páramo angiosperm plant species is endemic to this ecosystem. The Colombian Páramo areas can be grouped using PAE into five biogeographical units, based on angiosperm species composition. These are: (1) Páramos de la Cordillera Oriental; (2) Páramos de la Cordillera Central and Macizo Colombiano; (3) Páramos de Antioquia; (4) Páramos del Norte; (5) Páramos de la Cordillera Occidental.  相似文献   

11.
We analyze the relationship between palm species diversity and diversity of palm use in two areas (Amazonian Ecuador; Yucatan Peninsula) of equivalent size but with contrasting characteristics in palm species diversity and morphology, and in the phylogenetic composition of palm flora. The areas also differ in their cultural and socioeconomic contexts. Palm use diversity is significantly higher in the Ecuadorian Amazon than in the Yucatan Peninsula and the lower species diversity of palms in the Yucatan Peninsula is not matched by a more intensive use of the fewer species found there. The taxonomic composition of the palm flora is a poor predictor of extent of use and morphological characteristics of palm species affect usefulness only in the Ecuadorian Amazon. The Yucatecans’ more limited reliance on forest products might explain the observed patterns. Ornamental palm use is an indicator of a general change in plant use patterns associated with tourism and macro-economic development in the Yucatan Peninsula. We find a positive relationship between ecosystem plant diversity and plant use diversity, but socioeconomic factors such as market integration strongly influence the use of local biodiversity. Palms represent a diverse and important natural resource that deserves further investigation to secure its sustainable management and conservation in the two studied sites, regardless of their degree of market integration.  相似文献   

12.
Herbivorous animals face shortages of different minerals in different geographic areas. In the Amazon Basin, sodium is often limiting, driving herbivores to seek supplemental sources. In the lowlands of the western Amazon Basin, parrots commonly consume sodium‐rich soils at clay licks but lick use varies widely among species, and to date, parrots in the region have not been reported consuming other supplemental sodium sources. We document 11 species of psittacines consuming sodium‐rich leaves and trunks of Attalea butyracea palms growing on sodium‐rich soils in lowland Peru. Consumed palms had more sodium and less potassium than uneaten A. butyracea palms and other palm species in the area. Among A. butyracea palm parts, sodium and Na:K ratios were highest in trunks (consumed by parrots in 94% of the 387 foraging bouts recorded) and lowest in leaves (consumed in only 14% of foraging bouts). The low potassium and high Na:K ratio suggest that birds may be seeking not just any sodium sources, but those low in potassium, as potassium is known to exacerbate dietary sodium shortages. Use of the palms and species’ abundance in the study area were not correlated. Instead, parrot species that consumed palms the most were those that use relatively few traditional soil clay licks. This finding suggests that parrot species in the region have fundamental differences in preferred strategies for obtaining supplemental sodium and may help explain documented interspecific differences in geophagy.  相似文献   

13.
North western Argentina, the southernmost portion of the tropical Andes, contains one of the main areas of endemism within the Southern Cone, as well as one of the main diversity hotspots of the country. Historically its reserve area systems have been located in the richest ecoregion of the area; the Southern Andean Yungas. We evaluated the effectiveness of the current protected areas in preserving the endemic flora of the region. The distributions of 505 endemic species were either modeled or included as observed data to determine endemism hotspots in each ecoregion. The endemic species were mainly found in arid ecoregions such as the High Monte and the Central Andean Puna, as well as in the transition zones between these regions and the Southern Andean Yungas. We found that more than 1/3 of the endemic species are unprotected in their entire ranges by the current system, while nearly half of the species are protected in only 5 % of their distribution ranges. New priority areas were chosen to increase the effectiveness based on the irreplaceability concept. We show that adding 251 new cells of 100 km2 each would improve the protection values and convert the system to effective. The present paper highlights that priorities set on the basis of species richness may not successfully conserve areas of high plant endemism. However, zoologist would have to realize similar assessments in the endemic fauna in order to find the optimal designed of protected areas system to conserve both the endemic flora and fauna in the Southern Central Andes.  相似文献   

14.
We used palm knowledge to understand the interaction between people and the rainforests and the factors that influence this dynamic process. We interviewed 278 informants in 12 villages in the Pastaza and Madidi areas of the western Amazon basin. Together they used 38 different palm species for 38 different uses in six use-categories (food, construction, utensils, ritual, medicine, commercial). Euterpe precatoria, Iriartea deltoidea, and Oenocarpus bataua were best known and were mentioned as useful by 76–72% of the informants in the 12 villages. There was a great variation in number of uses and in how widespread the uses were and five of the 38 useful palms were mentioned by only one informant. Among the socioeconomic factors analyzed, the residence village influenced the informants’ knowledge of palms and their uses more than any other factor. Length of education, prosperity and for how long the informant had lived in the village were also positively correlated to how many palms and palm uses were known. Gender differences in informants’ knowledge of palm uses were not observed in our data. We suggest, that the high importance of forest products to the livelihood of the villagers, the great variation in the knowledge they possess, and the fact that the differences between villages is so great, are important elements to consider when developing management plans for the sustainable use of the rainforest resources in the western Amazon.  相似文献   

15.
Distributional patterns of Valeriana species from southern South America were analyzed. We prepared a database with the records of 40 species from Argentina and Chile south of 33°S, obtained from herbarium specimens, published taxonomic studies and field trips. We undertook a track analysis and a parsimony analysis of endemicity (PAE), the latter with 134 grid cells of 1.5° latitude by 1.5° longitude. Three generalized tracks and one node were obtained, and three areas of endemism were identified. These general patterns of distribution in Valeriana were used to infer possible vicariance and dispersal events that might have shaped them. We identified a center of diversification in Central Chile and the Argentinean province of Neuquén. It represents a complex area that is related to both the Central Chilean and Subantarctic subregions.  相似文献   

16.
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   

17.
Aim In this study we evaluate patterns of endemism for benthic polychaete species along the southeastern Pacific coast of Chile. Our goals were (1) to describe latitudinal gradients of endemism and identify areas of high endemism, (2) to evaluate the effect of biogeographical limits on endemism patterns, and (3) to evaluate indirectly the role played by evolutionary dynamics on patterns of endemism. Location South‐eastern Pacific coast of Chile, ranging from Arica (18° S) to Cape Horn (56° S). Methods We used a list of 178 species of endemic, shallow benthic polychaetes to evaluate patterns of endemism. Parsimony analysis of endemicity (PAE) and the endemism index (EI) were used to evaluate hierarchical relationships of endemism between different latitudinal bands, and to identify areas with high degrees of endemism and differences in endemism. We evaluated the effect of biogeographical limits on endemic polychaete fauna by testing for the existence of geometric constraints (mid‐domain effect). The role of evolutionary dynamics on latitudinal patterns of endemism was evaluated with nestedness analysis (NA) using the temperature index. Results The PAE analysis indicated two large, separate areas of endemism: (1) the northern area between 18° S and 38° S, and (2) the southern area between 39° S and 56° S. The endemism index showed a maximum value (32 species) around 39°–41° S. Species‐richness curves of each 3° band of latitude showed a clear mid‐domain effect (69%), but the two maximum points of species richness at mid‐latitudes (36° S to 38° S and 39° S to 41° S) did not correspond to the mid‐domain peak in species richness, presenting a greater number of species than expected by the mid‐domain effect. The nestedness analysis showed that the number of genera reaches a maximum of 70 at mid‐latitudes (36°–41° S), decreasing towards both the northern and southern areas. The spatial distribution of the entire data set of endemic species showed a nested pattern (T° = 24.5°, P < 0.0001). Main conclusions Our results strongly support the existence of a latitudinal gradient of endemism for benthic polychaete species along the Chilean coast. The shape of this gradient is clearly non‐linear, with a marked peak of endemism occurring at mid‐latitudes (36°–41° S, endemism hotspot), which also corresponds to a peak in species richness. Furthermore, this hotspot is the midpoint separating two distinct areas of endemism to the north and south. We suggest that the observed pattern of endemism for benthic polychaete taxa of the Chilean coast can be explained by a combination of geometric constraints and historical mechanisms, such as the processes that affected the Chilean coast during the Neogene (e.g. ENSO, oxygen minimum zone, glaciations).  相似文献   

18.
Field work and data from herbaria collections (2686 records) representing 283 taxa (265 species and 18 infraspecific taxa) of Bromeliaceae occurring at Minas Gerais state, southeastern Brazil, were analyzed in order to obtain distribution and diversity information, and to determine IUCN (The World Conservation Union) conservation status for each taxon. A map containing 1° × 1° grid cells was used to identify priority areas for new research collections, areas of high species diversity, and Bromeliaceae conservation status. A clear decrease in Bromeliaceae diversity is observed between the eastern and the western portions of Minas Gerais, and low floristic similarities were found between neighboring grid cells. The rocky mountains of Cadeia do Espinhaço are considered the most important area for Bromeliaceae endemics. From the 283 taxa of Bromeliaceae that occur at Minas Gerais, 118 (42%) are considered threatened, and 124 taxa (44% of the total) do not occur inside any protected area. The region of the Quadrilátero Ferrífero in the southern portion of the Cadeia do Espinhaço is the most threatened, and urgent strategies for conservation of this rich Bromeliaceae flora are needed. Northeastern Minas Gerais, particularly the rocky outcrops or inselbergs located in the Jequitinhonha and Mucuri rivers drainage basins need additional collection efforts and conservation actions focused on these saxicolous taxa.  相似文献   

19.
海南岛野生兰科植物多样性及其保护区域的优先性   总被引:11,自引:0,他引:11       下载免费PDF全文
兰科是显花植物中的一个大类群,世界约有800属25 000种,全世界所有野生兰科植物均被列入《濒危野生动植物物种国际贸易公约》的保护范围,是植物保护中的“旗舰”类群。中国是野生兰科植物最重要的多样性中心之一,约有171属1 247种。作为中国的典型热带地区,海南岛具有丰富的野生兰科植物资源。该文系统地收集和整理了海南岛野生兰科植物资源信息,以海南岛19个行政县为基本分布区,构建海南岛野生兰科植物数据库,采用特有性简约分析(Parsimony analysis of endemicity)和互补分析(Complementarity analysis)两种方法,探讨海南岛野生兰科植物多样性保护的最低保护区组合和区域保护优先序问题。结果表明:海南岛约分布有野生兰科植物77属202种(30个中国特有种),其多样性保护的关键区域为南部和西南部地区;基于物种相似性,两个区域被建议作为优先保护区域:一个是以保亭、三亚和陵水为代表的区域,另一个区域以昌江和乐东为代表;基于互补性原理,最低保护区组合为10个分布区,按照其保护优先序依次排列为保亭、三亚、五指山、陵水、白沙、乐东、琼中、东方、昌江和琼山等地,其中陵水、保亭、琼中、乐东、三亚和五指山等6个分布区就包含了30个特有科在内。我们认为,基于海南岛野生兰科植物建立优先保护区域,利用有限的资源达到最优的保护,是一个较为合理、科学和高效的保护策略。  相似文献   

20.
Abstract Aim Parsimony analysis of endemicity (PAE) is a biogeographical method that uses a parsimony algorithm to obtain an area cladogram, based on taxa inhabiting the study areas. We compare its performance at different geographical units (½° and 1° quadrats, ecoregions and biogeographical provinces) to analyse distributional patterns of Mexican terrestrial mammals, in order to assess the importance of the size of area units. Location The area analysed corresponds to Mexico. Methods Parsimony analyses were based on 56,859 collection records, corresponding to 703 genera, species and subspecies. Four data matrices were constructed for: (1) 716 quadrats of ½° latitude × ½° longitude, (2) 230 quadrats of 1° latitude × 1° longitude, (3) forty‐five ecoregions and (4) fourteen biogeographical provinces. Results For the ½° quadrat matrix, we obtained six cladograms of 17,138 steps. For the 1° quadrat matrix, we obtained five cladograms (strict consensus with 9394 steps). For the matrix of ecoregions, we obtained twelve cladograms (strict consensus cladogram with 3009 steps). For the provinces, we obtained a single cladogram with 1603 steps. Main conclusions The best results were obtained with natural areas instead of quadrats. There seems to exist a trend to decrease the absolute number of steps and an increase in the absolute and relative number of synapomorphies as the size of the area units decreases, although this does not necessarily occur for the number of cladograms.  相似文献   

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