Endemicity Analysis Research Articles

Patterns of Species Richness and Its Endemism of Beetles in the Beijing–Tianjin–Hebei Region of China

The Beijing–Tianjin–Hebei region lies between the Mongolia-Xinjiang Zoogeographic Region and the Central China Zoogeographic Region in China, harboring relatively rich biodiversity. This study specifically examined the species diversity, richness and endemic areas of beetles in this area. By analyzing 5965 detailed distribution records of 2047 beetle species in the Beijing–Tianjin–Hebei region, the species richness maps were created with a grid size of 0.5°. Additionally, two methods, parsimony analysis of endemism (PAE) and endemicity analysis (EA) were applied to detect areas of endemism (AOEs) with different grid sizes (0.1°, 0.25° and 0.5°), resulting in the identification of three AOEs in the southern mountainous areas of the Taihang Mountains, Yanshan Mountains, and Xiaowutai Mountains. It also verified that AOEs are consistent with the hypothesis that endemic areas are predominantly located in mountain ranges, as proposed by previous related studies. These findings highlight the importance of complex topography and stable climate in shaping AOEs and conserving biodiversity.

Areas of Endemism and Biogeographic Regionalization of the Iberian Peninsula Based on Ants (Hymenoptera: Formicidae)

Based on the distribution of 275 species of ants native to the Iberian Peninsula (IP), we identified areas of endemism (AE) within its geographical limits and present a biogeographic regionalization using two complementary methods and two types of operational geographical units. For endemicity analysis (EA), we used a 100 km2 grid cell, and for parsimony analysis of endemicity (PAE), we used hydrological basins as natural units. The EA revealed twelve areas of endemism that were grouped into five consensus areas. These are the Northeastern area, South plateau, Guadalquivir Valley, Baetic System, and Iberian Peninsula (whole). PAE resulted in a cladogram that classified hydrological basins into at least two successively nested subsets: an Atlantic group that is more related to northern European fauna and an Iberian subset that is well supported by synapomorphies. The Iberian subset was differentiated into four main areas: (a) a Northeastern area formed by the Pyrenees and the Catalan Coastal Range, (b) a mainland area containing the Central System and Guadiana and Tajo valleys, (c) a Southern area consisting of the Guadalquivir Valley and the Baetic System, and (d) a Northern coastal area. The results showed congruence between the two methods since many of the synapomorphies are shared among the diagnostic and IP endemic species of the EA. Both EA and PAE showed the relevance of the heterogeneous peninsular orography that combines mountainous regions with valleys and plateaus, which have acted as historical barriers or corridors. The presence of numerous endemic species, particularly in the southern third of the IP, suggests that several Iberian refuges for ants originated during glacial periods. These areas constitute priority sites for the conservation of ants in particular and biodiversity in general on the IP and allow further research about the processes that generated these distributional patterns.

Areas of Endemism of Plants in the South-Central and Southwestern Nearctic Region

The history and connections of the flora of south-central/southwestern (SC/SW) North America have been studied and summarized in biogeographic regionalization. However, some studies show contrasting delineations of the SC/SW North American provinces that could be better determined using quantitative methods. We aimed to find spatial patterns of a set of plants in the SC/SW United States by conducting endemicity analysis (EA) on different scales. We first built a dataset with 81,965 specimen point records of 400 species from 174 genera and 61 families of angiosperms and two genera of gymnosperms using digitized specimen data from iDigBio. We then performed EA at four different scales to identify the areas of endemism (AoEs).
 We obtained 28 AoEs with different cell sizes by selecting each AoE under the grid size that yielded the highest number of high-scoring species. The study region split into two significant centers of accumulation of nested or partially overlapping AoEs: the SW and SC consensus areas. In these parts of the Nearctic region, many genera/clades, among those in the dataset, showed a geographic split into western and eastern clades. The split corresponded to an environmental and physical barrier known as Cochise Filter Barrier. The Sonora–Mojave arid center, parts of South Texas, and the Chihuahuan Desert harbor basally branching taxa of several genera and even families, based on the observations of some species, which allowed identification of the AoEs.

Exploring the Species Richness Pattern and Areas of Endemism of Tenebrionidae (Coleoptera) in Xinjiang, China

Species richness and areas of endemicity (AOE) are the basis of biogeography, which is of great significance for understanding the evolution of species and making conservation plans. The present study aimed to investigate the species richness pattern and AOEs of Tenebrionidae in Xinjiang, China. We collected information on the geographical distribution of 556 species from several sources and obtained 2226 distribution records for the analyses. The AOEs were detected using the parsimony analysis of endemicity (PAE) and endemicity analysis (EA) at 0.5°, 1°, and 1.5° grid sizes, respectively. A total of six AOEs were found, including three mountain ranges (Altai Mountains, Tianshan Mountains, and Kunlun Mountains) and one basin (Junggar Basin), which was largely congruent with the species richness pattern. The results indicated that the complex terrain and stable climate in the mountainous area played an important role in the formation of tenebrionid species diversity and their endemic areas in Xinjiang.

Assessing the Diversity and Distribution Pattern of the Speciose Genus Lycocerus (Coleoptera: Cantharidae) by the Global-Scale Data

Species richness patterns and endemism on the large-scale play a significant role in biogeography and biodiversity conservation. This study aimed to explore the diversity centers and endemic areas of a large cantharid genus Lycocerus, so as to test whether the hypothesis of montane and island systems biodiversity in previous studies was supported. In this study, a comprehensive species’ geographical database on the global scale consisting of 4,227 records for 324 Lycocerus species was compiled and analyzed. Species richness pattern was mapped into a grid-based map with a spatial resolution of 1° × 1° fishnet. An unbalanced pattern was identified, and it showed that the centers of species richness of Lycocerus were situated in Eastern Himalayas, Hengduan Mountains, Eastern Sichuan Mountains, Taiwan, and Japan. Further analyses based on two approaches, including parsimony analysis of endemicity (PAE) and endemicity analysis (EA), were applied to detect areas of endemism (AOEs) at three different grid sizes (1°, 1.5°, and 2°). Finally, a total of nine AOEs were detected, including five montane areas (Himalayan areas, Hengduan Mountains, South edge of China, Eastern China Mountains, and Eastern Sichuan Mountains), three islands (Taiwan Island, Japan, and Korean Peninsula), and one plateau (Shan Plateau), which were generally consistent with the species richness pattern. The results verify that montane and island systems have an essential role in promoting the formation of diversity centers and AOEs because of their complex topography, varied habitat and geological events.

Areas of endemism of two biogeographic provinces in central Mexico based on their endemic Asteraceae: a conservation proposal

The Transmexican Volcanic Belt (TVB) and the Balsas Basin (BB), situated in central Mexico, stand out for their species richness and endemism. Documenting patterns of distribution of endemism is relevant, since species restricted to an area may become sensitive to the modification of their environment. The aim of this study was to identify areas of endemism within the TVB and the BB based on a set of species of Asteraceae endemic to these provinces. A Parsimony Analysis of Endemicity (PAE) and an Endemicity Analysis (EA) were carried out from a database with 901 records, using 30’ latitude and longitude grid-cells, and hydrological sub-basins as units. Based on 148 endemic species, between 1 and 8 areas of endemism were identified in both biogeographic provinces. In particular, the TVB concentrates 79 endemic Asteraceae, which represent 53.3% of the total analyzed species. The areas of endemism identified are irreplaceable zones and stand out as important sites for the conservation of local endemism, which is an extremely important criterion for the definition of priority areas for conservation.

Two centuries of distribution data: detection of areas of endemism for the Brazilian angiosperms.

Brazil has high levels of biodiversity and has received strong criticism for the increasing country-wide deforestation that threatens it. Although a significant percentage of land area in Brazil is protected, the areas are insufficient and unevenly distributed. Many studies have contributed to the biogeographical knowledge of Brazilian flora, but no endemicity analysis (EA) has been conducted including all endemic angiosperms. We investigated the spatial component, drawing on a huge and taxonomically diverse dataset based on 827016 records collected over the last two centuries. We conducted an EA for 15034 species from 173 families using an optimality criterion with 2° and 3° grid sizes, in order to search for distributional concordance, to identify the biogeographical units and discuss the implications for conservation. Six analyses were run for basal angiosperms, monocots and eudicots. The EA recovered 66 consensus areas (CAs). The concordance of CAs enabled the identification of five best-supported areas of endemism--three in the Atlantic and Parana Forest and two areas in the Cerrado province--supported by species of 120 families. The age of divergence for some genera that contributed significantly to the identification of areas recovered in the Cerrado coincides with the recent, <10Ma, estimated age of that province. By contrast, the areas in the Atlantic and Parana Forest are supported by genera with earlier diversification >30Ma, supporting an ancient origin. Most areas in the Atlantic Forest are partially superimposed with the limits of the protected areas, however, big gaps were identified in the Cerrado. Protecting Brazilian biomes was at the heart of Brazil's environmental policy. Regrettably, this scenario has radically changed based on misleading divergences in conservation policy. Areas of endemism are pivotal for biodiversity conservation due to the common evolutionary history shared by their endemic taxa. Thus, we hope that these congruent patterns of endemism support the establishment of biodiversity priorities.

Areas of endemism of land planarians (Platyhelminthes: Tricladida) in the Southern Atlantic Forest.

Areas of endemism (AoE) are the main study units in analytical biogeographic methods, and are often defined as an area with two or more endemic species living in them, presenting substantial congruence among their range limits. We explored the distribution of land planarians (Geoplanidae, Platyhelminthes) across the southern region of the Brazilian Atlantic forest (from the state of Rio de Janeiro, to the state of Rio Grande do Sul) utilizing DaSilva's et al. (2015) protocol. We used two methods, Endemicity Analysis (EA), and Geographical Interpolation of Endemism (GIE). We identified nine AoE of terrestrial flatworms in the Southern Atlantic forest. Performance of the methodologies is discussed. These AoE of land planarians can be explained through vicariance events combined with their physiological and ecological own limitations. Interestingly, these AoE are congruent with fine-scale approaches such as that with harvestmen. Most land planarians have revealed to present a very small distributional range evidencing their potential as a good model for fine-scale studies of AoE.

Distribution of the xeric clade species of Pitcairnioideae (Bromeliaceae) in South America: a perspective based on areas of endemism

AbstractAimThe main goals were to assess the distributional concordance among taxa of the xeric clade of Pitcairnioideae (Bromeliaceae) to establish biogeographical units (i.e. endemic areas), and to use the results to identify conservation priorities.LocationGeographical data were analysed between parallels −1° and −47° S and meridians 35°6′ and 80°1′ W, which includes the Andean region, the Chacoan subregion and the South American Transition Zone, and three global hotspots (Atlantic Forest, Cerrado and Tropical Andes).MethodsTwo methods were employed, parsimony analysis of endemicity (PAE) and endemicity analysis (EA), to search for the biogeographical congruence between endemic areas for 220 species. Two grid cell sizes (2° and 3°) and three criteria were employed to delimit the areas of endemism.ResultsThe results of the PAE demonstrated eight candidate areas of endemism when applying a grid cell size of 2° and six areas of endemism with 3°. The EA optimization method, using a grid size of 2°, recovered six (consensus 75%) and four (consensus 5%) areas, and a size of 3° recovered eight (consensus 75%) and three (consensus 5%) areas. Based on consistent results of the three combined criteria and the congruence of areas of endemism, we delimited three biogeographical areas of endemism for the clade in the Chacoan subregion of South America. The following areas in Brazil were delimited: (1) south‐eastern Minas Gerais, (2) north‐eastern Minas Gerais, and (3) north‐eastern Goiás.Main conclusionsEndemic species with congruent occurrence patterns were identified to propose primary biogeographical homologies and to highlight areas that should be prioritized for conservation of species in the xeric clade of Pitcairnioideae. Furthermore, we suggest that evolutionary and historical processes (adaptive radiation; glacial and interglacial period in the Quaternary), as well as ecological factors, could have induced the high diversification rates for this clade in South America.

Comparison between Parsimony Analysis of Endemicity (PAE), Endemicity Analysis (EA), and an alternative coding of Three-Distribution Statements based on hypothetical distributions

Areas of endemism are identified by a variety of methods, none of which is universally accepted. Performance of each method depends upon the variables chosen. Here, we compare Parsimony Analysis of Endemicity (PAE), Endemicity Analysis (EA), and a new coding method that we propose, Three-Distribution Statements (3DS). We rate performance based on the ability to identify hypothetical predefined patterns that represent non-conflicting, nested, and overlapping areas of endemism. Additionally, we also compared properties commonly used in analyses, such as shape and size of the area and the number of taxa involved. We found that 3DS has the best performance in retrieving predefined areas. EA is the only method that resolved a completely overlapping pattern, but it also found spurious patterns. Resolution with PAE always had intermediate precision and efficiency and so is not the best option for analysis of endemism. We recommend the use of 3DS together with EA as the best available option for hypothesizing areas of endemism.

Evaluación de AE y PAE para identificar trazos generalizados, a partir de las serpientes del estado de Hidalgo, México

One of the most important concepts in Panbiogeography is the generalized track, which represents an ancestral biota fragmented by geological events that can be recovered through several methods, including Parsimony analysis of endemicity (PAE) and endemicity analysis (EA). PAE has been frequently used to identify generalized tracks, while EA is primarily designed to find areas of endemicity, but has been recently proposed for identifying generalized tracks as well. In this study we evaluated these methods to find generalized tracks using the distribution of the 84 snake species of Hidalgo. PAE found one generalized track from three individual tracks (Agkistrodon taylori, Crotalus totonacus and Pliocercus elapoides), supported by 89 % of Bootstrap, and EA identified two generalized tracks, with endemicity index values of 2.71-2.96 and 2.84-3.09, respectively. Those areas were transformed to generalized tracks. The first generalized track was retrieved from three individual tracks (Micrurus bernadi, Rhadinaea marcellae and R. quinquelineata), and the second was recovered from two individual tracks (Geophis mutitorques and Thamnophis sumichrasti). These generalized tracks can be considered a unique distribution pattern, because they resembled each other and agreed in shape. When comparing both methods, we noted that both are useful for identifying generalized tracks, and although they can be used independently, we suggest their complementary use. Nevertheless, to obtain accurate results, it is useful to consider theoretical bases of both methods, along with an appropriate choice of the size of the area. Results using small-grid size in EA are ideal for searching biogeographical patterns within geopolitical limits. Furthermore, they can be used for conservation proposals at state level where endemic species become irreplaceable, and where losing them would imply the extinction of unique lineages.

Areas of endemism of the North American species of Tigridieae (Iridaceae)

The tribe Tigridieae (Iridoideae: Iridaceae) is a New World group with centres of diversity in Mexico and Andean South America. North America harbours 67 of the 172 species recognised within the tribe, 54 being endemic. Our aims were to identify areas of endemism of the North American Tigridieae using endemicity analysis (EA) and to infer their relationships using parsimony analysis of endemicity (PAE). A data matrix with 2769 geographical records of Tigridieae was analysed. The EA allowed to identify six consensus areas of endemism in Mexico. The PAE resulted in one cladogram with four clades and the following five biotic components: northern Mexico, western Mexico, central Mexico, southern Mexico and central–southern Mexico. The richness analysis of these areas of endemism indicated that the greatest concentration of species is located in central Mexico, with 14 species in one grid-cell. Grid-cells with 12 species each were identified in low western Mexico, high western Mexico, southern Mexico and central–southern Mexico. This last area is characterised by the greatest endemism, including nine species. The formation of the Transmexican Volcanic Belt seems to have been a key element to explain the diversification of North American Tigridieae.

Areas of endemism in the Southwestern Atlantic Ocean based on the distribution of benthic hydroids (Cnidaria: Hydrozoa).

Geographic distributions of 130 species of benthic hydroids were used to infer areas of endemism in the Southwestern Atlantic Ocean (SWAO, between 22°S and 55°S). Endemicity Analysis (EA) was carried out with the software NDM VNDM, using a 2° x 2° grid with different values of F (F = 0.5 and F = 1.0) for inferred presence. Hypothesized areas of endemism (16 with F = 0.5 and 13 with F = 1.0) formed three generalized patterns: (1) Tropical, (2) Subtropical, and (3) disjunctions along Tropical and Subtropical areas. Areas of endemism estimated here were compared with provinces, ecoregions and areas of endemism previously defined (but not based on algorithmic analysis) in the literature. Ecological and historical aspects that are potentially relevant for the SWAO realm were contrasted, related and discussed to areas of endemism. This is the first study to apply NDM VNDM to the marine realm and one of the few that focuses on the SWAO.

Parsimony analysis of endemicity and analysis of endemicity: A fair comparison

Parsimony Analysis of Endemicity (PAE) has been compared with other methods regarding its performance to identify areas of endemism. It is frequently compared with the Analysis of Endemicity (AE), which seems to perform better than PAE to identify these areas. Here I compare PAE and AE considering the sympatric taxa diagnosed as endemic, being as strictly close as possible to sympatry, and using previously published data of Sciobius (Coleoptera: Curculionidae). AE identified more candidate areas of endemism than PAE, but the number of highly restricted endemic taxa to these areas was insufficient to support them as areas of endemism. Considering strictly sympatry (homopatry), PAE performed better than AE; however, both methods may identify areas with some grade of sympatry, but the recognition of which areas constitute real areas of endemism in the strict sense depends on the interpretation of the researcher.

Parsimony analysis of endemicity (PAE) revisited

AbstractSeveral methods have been proposed for use in identifying and classifying areas of endemism. Parsimony analysis of endemicity (PAE) is the most widely used. It constructs cladograms based on the cladistic analysis of presence–absence data matrices of species and supraspecific taxa. Several authors have criticizedPAE, usually because they have misunderstood its theoretical basis. A summary of the procedure is presented here, along with a discussion of the interpretation ofPAEcladograms. Some critics deny any place in evolutionary biogeography for non‐phylogenetic approaches, but I believe evolutionary biogeography is a pluralistic discipline, wherePAEhas a place despite lacking a strictly phylogenetic perspective, and thus can be applied as the first step in an analysis. Other authors criticize the use ofPAEas a cladistic biogeographical method, although their arguments may be circular because they refer to biogeographical analyses based on phylogenetic hypotheses. Finally, the use ofPAEfor identifying areas of endemism has been criticized because an optimality criterion is used a posteriori to select areas of endemism found by what have been considered as less appropriate means, and endemicity analysis (EA) has proved to be more efficient thanPAEfor identifying areas of endemism. Over the last few decadesPAEhas been used extensively to identify areas of endemism and to determine their relationships, playing a relevant role in evolutionary biogeography.

Biogeographic regions of North American mammals based on endemism

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.

Endemicity analysis, parsimony and biotic elements: a formal comparison using hypothetical distributions.

There is as yet no general agreement regarding the most appropriate solution to the problem of identifying areas of endemism, not even in particular cases. In this study, we compared Endemicity Analysis (EA), Parsimony Analysis of Endemicity (PAE), and Biotic Elements Analysis (BE) based on their ability to identify hypothetical predefined patterns that represent nested, overlapping, and disjoint areas of endemism supported by species with different degrees of sympatry. We found that PAE performs poorly when applied to patterns that either overlap with each other or are supported by species with imperfect sympatry. BE exhibits a counterintuitive sensitivity to the degree of congruence among the distributions of endemic species, being unable to recognize areas of endemism supported by perfectly sympatric species. In contrast, in all cases examined we found that EA results in a high proportion of correctly identified distributional patterns. In addition to highlighting the strengths and limitations of these approaches, our results show how different methods can lead to seemingly conflicting conclusions and caution about the possibility of identifying distributional patterns that are merely methodological artefacts. © The Willi Hennig Society 2012.

Areas of endemism of the Patagonian steppe: an approach based on insect distributional patterns using endemicity analysis

AbstractAims To delimit areas of endemism in the Patagonian steppe using endemicity analysis (EA), which evaluates areas of endemism by means of an endemicity index, and to compare the resulting endemic areas with those proposed for the Patagonian steppe by previous authors.Location The Patagonian steppe, a region of South America found approximately below parallel 36° S to the east of the Andes Mountains.Methods Distributional data for 159 species of insects collected in the Patagonian steppe, and consisting of 1317 georeferenced samples were used to identify areas of endemism. A data grid of presence and absence (with cells of 1° × 1°) was constructed. Initially, two different types of EA were performed, seeking areas defined by ‘four or more’ species. A first analysis was performed without taking into consideration those quadrats where no species had been recorded (empty quadrats), which in many cases meant a discontinuous distribution. The second analysis was performed assuming a continuous distribution for each species. A third analysis, assuming continuous distributions, was performed using ‘three or more’ as the number of species necessary for an area to be identified as an endemic area.Results In the first two analyses, EA recognized the same five areas of endemism: western Patagonia, south‐western Payunia, northern Suabandean, southern Subandean and Austral Patagonia. The results of the third analysis allowed the identification of three more areas of endemism: northern Payunia, Chubutian and Santacrucian.Main conclusions We identified five areas of endemism for the Patagonian steppe, some of which have been defined in previous contributions. These areas are: Western Patagonia, Payunia and Subandean Patagonia (which can be divided into septentrional and meridional), Central Patagonia (Chubutence and Santacrucense) and Austral Patagonia.