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Marine macroalgal biodiversity hotspots: why is there high species richness and endemism in southern Australian marine benthic flora? 总被引:1,自引:0,他引:1
Julie A. Phillips 《Biodiversity and Conservation》2001,10(9):1555-1577
The southern Australian marine macroalgal flora has the highest levels of species richness and endemism of any regional macroalgal flora in the world. Analyses of species composition and distributions for the southern Australian flora have identified four different floristic elements, namely the southern Australian endemic element, the widely distributed temperate element, the tropical element and a cold water element. Within the southern Australian endemic element, four species distribution patterns are apparent, thought to largely result from the Jurassic to Oligocene fragmentation of East Gondwana, the subsequent migration of Tethyan ancestors from the west Australian coast and the later invasion of high latitude Pacific species. Climatic deterioration from the late Eocene to the present is thought responsible for the replacement of the previous tropical south coast flora by an endemic temperate flora which has subsequently diversified in response to fluctuating environmental conditions, abundant rocky substrata and substantial habitat heterogeneity. High levels of endemism are attributed to Australia's long isolation and maintained, as is the high species richness, by the lack of recent mass extinction events. The warm water Leeuwin Current has had profound influence in the region since the Eocene, flowing to disperse macroalgal species onto the south coast as well as ameliorating the local environment. It is now evident that the high species richness and endemism we now observe in the southern Australian marine macroalgal flora can be attributed to a complex interaction of biogeographical, ecological and phylogenetic processes over the last 160 million years. 相似文献
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Lantoniaina Andriamampianina Claire Kremen Dick Vane-Wright David Lees Vincent Razafimahatratra 《Journal of Insect Conservation》2000,4(2):109-128
Distributional ranges of 17 genera and 172 species of Malagasy tiger beetles (Coleoptera, Cicindelidae) have been compiled to determine patterns of species richness and endemism. These patterns reveal large sampling gaps, and potential priority areas for conservation action. Northern and south-western parts of the island are richer in genera, whereas eastern and especially northern parts of the rainforest show higher species richness, due to extensive radiations within the genera Pogonostoma and Physodeutera. A set of 23 areas are identified in this study as priority foci for tiger beetle conservation, and six general regions are bioinventory priorities. 相似文献
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Aim To assemble a continental‐scale data set of all available anuran records and investigate trends in endemism and species richness for the Anura. Location Continental Australia. Methods 97,338 records were assembled, covering 75% of the continent. A neighbourhood analysis was applied to recorded locations for each species to measure richness and endemism for each half‐degree grid square (c. 50 km) in the continent. This analysis was performed for all anurans, and also for each of the three main anuran families found in Australia. A Monte Carlo simulation was used to test a null hypothesis that observed centres of endemism could result simply from an unstructured overlapping of species ranges of different sizes. Results Eleven main centres of anuran endemism were identified, the most important being the Wet Tropics and the south‐west near Bunbury‐Augusta and near Walpole. With the exception of south‐western Australia, all of the identified significant endemic centres are in the northern half of the continent. The regions identified as significant for endemism differed from those identified for species richness and are more localized. Species richness is greatest in the Wet Tropics and the Border Ranges. High species richness also occurs in several areas not previously identified along the east and northern coasts. Main conclusions Weighted endemism provides a new approach for determining significant areas for anuran conservation in Australia and areas can be identified that could be targeted for beneficial conservation gains. Patterns in endemism were found to vary markedly between the three main anuran families, and south‐eastern Australia was found to be far less significant than indicated by previous studies. The need for further survey work in inland Australia is highlighted and several priority areas suggested. Our results for species richness remain broadly consistent with trends previously observed for the Australian Anura. 相似文献
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Phylogenetic reassessment and biogeography of the Ectateus generic group (Coleoptera: Tenebrionidae: Platynotina) 下载免费PDF全文
Marcin Jan Kamiński 《Zoological Journal of the Linnean Society》2015,175(1):73-106
Owing to the reinterpretation of its morphological synapomorphies, the taxonomic composition of the Ectateus generic group had been ambiguous. The present study scrutinized all existing taxonomic concepts of the group based on a cladistic analysis of the adult morphology of all of the Afrotropical platynotoid Platynotina genera. The phylogenetic relationships were reconstructed using parsimony and Bayesian inference. The results show that all previous taxonomic concepts of the Ectateus generic group concerned paraphyletic entities. The cladistic analysis revealed the following synapomorphies for the taxon: (1) presence of basal indentations of the pronotal disc, (2) ratio of prothorax width to its maximal height > 6.0, and (3) ratio of maximal height of the prothorax to total height < 0.3. Moreover, phylogenetic studies revealed the existence of the Upembarus generic group, a sister‐taxon group to the Ectateus generic group, within the Afrotropical platynotoid Platynotina. Autapomorphic and synapomorphic character mapping show that several taxonomic and nomenclatural changes are needed to consider the particular generic‐level entities traditionally assigned to Afrotropical platynotoid Platynotina as monophyletic lineages. The following taxonomic and nomenclatural adjustments are made in this paper: P teroselinus gen. nov. is erected to accommodate a single species that was previously assigned to Zidalus: Pteroselinus insularis comb. nov. Additionally, the following synonymies are proposed: Anchophthalmops (= Platykochius syn. nov. ), Angolositus (= Aberlencus syn. nov. , = Platymedvedevia syn. nov. ), Glyptopteryx (= Microselinus syn. nov. , = Quadrideres syn. nov. , = Synquadrideres syn. nov. ). In addition, Kochogaster is lowered in rank and is treated as one of the subgenera of Anchophthalmus. Moreover, Pseudoselinus is treated as a subgenus of Upembarus. An identification key to all Afrotropical platynotoid Platynotina genera and subgenera is presented. Zoogeographical analyses revealed the following dispersal barriers for the Ectateus generic group: (1) the Sahara (northern barrier); (2) the dry ecosystems of Botswana, Namibia, and South Africa (southern barrier); and (3) the Congolian rainforests (internal distributional gap). The ancestor of the taxon probably originated in East African ecoregions that predominantly contained wattletrees (acacias) and Commiphora Jacq. Moreover, past climate changes seem to have had a great impact on the observed generic distribution. © 2015 The Linnean Society of London 相似文献
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Jorge M. Lobo Jean-Pierre Lumaret† Pierre Jay-Robert† 《Global Ecology and Biogeography》2002,11(4):265-277
Aim To predict French Scarabaeidae dung beetle species richness distribution, and to determine the possible underlying causal factors. Location The entire French territory has been studied by dividing it into 301 grid cells of 0.72 × 0.36 degrees. Method Species richness distribution was predicted using generalized linear models to relate the number of species with spatial, topographic and climate variables in grid squares previously identified as well sampled (n = 66). The predictive function includes the curvilinear relationship between variables, interaction terms and the significant third‐degree polynomial terms of latitude and longitude. The final model was validated by a jack‐knife procedure. The underlying causal factors were investigated by partial regression analysis, decomposing the variation in species richness among spatial, topographic and climate type variables. Results The final model accounts for 86.2% of total deviance, with a mean jack‐knife predictive error of 17.7%. The species richness map obtained highlights the Mediterranean as the region richest in species, and the less well‐explored south‐western region as also being species‐rich. The largest fraction of variability (38%) in the number of species is accounted for by the combined effect of the three groups of explanatory variables. The spatially structured climate component explains 21% of variation, while the pure climate and pure spatial components explain 14% and 11%, respectively. The effect of topography was negligible. Conclusions Delimiting the adequately inventoried areas and elaborating forecasting models using simple environmental variables can rapidly produce an estimate of the species richness distribution. Scarabaeidae species richness distribution seems to be mainly influenced by temperature. Minimum mean temperature is the most influential variable on a local scale, while maximum and mean temperature are the most important spatially structured variables. We suggest that species richness variation is mainly conditioned by the failure of many species to go beyond determined temperature range limits. 相似文献
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The distribution of tropical plant and animal diversity is still poorly documented, especially at spatial resolutions of practical use for conservation. In the present study, we evaluated the level to which geographical incomplete data availability of species occurrence affects the perception of biodiversity patterns (species richness and endemism) among pteridophytes in Bolivia. We used a data base of Bolivian pteridophytes (27,501 records), divided it into three time periods (1900–70, up to 1990 and up to 2006), and created grid-files at 15'-resolution for species richness and endemism. For each of these biodiversity properties we estimated the species richness (Chao 2) and the index of sampling completeness (C index) per grid, and then all these variables at both species richness and endemism were correlated. Patterns of richness were fairly consistent along all periods; the richest areas were placed along the humid-montane forest, even though they were strongly influenced by collecting intensity. Endemism had a lower degree of correlation with collecting intensity, but varied much more strongly through time than species richness. According to the C index, which gives the ratio between estimated (by Chao 2) and recorded values of species richness and endemism, both biodiversity properties tended to be undersampled in the richest grid cells. Inter-temporal correlations showed sharper differences of correlations for endemism than species richness. Consequently, already in 1970, botanists had a correct idea of the spatial distribution of pteridophyte richness in Bolivia (even though the magnitude was grossly underestimated). In contrast, patterns of endemism, which are of high conservation importance, may not even today be reliably known. 相似文献
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The coincidence of rarity and richness and the potential signature of history in centres of endemism 总被引:4,自引:0,他引:4
We investigate the relative importance of stochastic and environmental/topographic effects on the occurrence of avian centres of endemism, evaluating their potential historical importance for broad‐scale patterns in species richness across Sub‐Saharan Africa. Because species‐rich areas are more likely to be centres of endemism by chance alone, we test two null models: Model 1 calculates expected patterns of endemism using a random draw from the occurrence records of the continental assemblage, whereas Model 2 additionally implements the potential role of geometric constraints. Since Model 1 yields better quantitative predictions we use it to identify centres of endemism controlled for richness. Altitudinal range and low seasonality emerge as core environmental predictors for these areas, which contain unusually high species richness compared to other parts of sub‐Saharan Africa, even when controlled for environmental differences. This result supports the idea that centres of endemism may represent areas of special evolutionary history, probably as centres of diversification. 相似文献
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Measuring and mapping endemism and species richness: a new methodological approach and its application on the flora of Africa 总被引:5,自引:5,他引:0
The adjustment of an existing index which combines endemism and species richness (Williams 1993) is proposed so that it requires markedly less data on the study area and its flora or fauna than was necessary with the conventional calculation method. Using this adjusted method, the resulting scores are calculated and mapped for the seed plant flora of the 20 African regions as delineated by White (1983). We argue that this index, here referred to as a measure of endemism richness, can be regarded as the specific contribution of an area to global biodiversity. We demonstrate that at a given sampling scale it shows a linear relation with area. We further demonstrate that, within certain limits, this linearity can also be observed in many cases when sampling scales vary which makes the comparison of differently sized geographic units easier than is the case for species richness. The two most important advantages over species richness are that this index is more suitable to measure both the conservation value of an area and the negative impact of invaders. The latter quality is due to the fact that it yields scores which usually do not rise substantially but can rather be expected to drop in many cases when an area is invaded by alien species. 相似文献
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D. K. Bharti Gregory D. Edgecombe K. Praveen Karanth Jahnavi Joshi 《Ecology and evolution》2021,11(23):16499
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
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The genus ErulipusFairmaire, 1903 (previously in the subfamily Tenebrioninae, tribe Helopini), after the study of the type species (Erulipus fruhstorferiFairmaire, 1903), is transferred to the genus AinuLewis, 1894 (subfamily Stenochiinae, the tribe Cnodalonini) as a subgenus. Consequently, two new combinations are established: Ainu (Erulipus) fruhstorferi (Fairmaire, 1903), comb. nov. and Ainu (s. str.) multicolor (Pic, 1927), comb. nov. The syntypes of Erulipus fruhstorferi and Erulipus multicolorPic, 1927 are studied and the new synonym is proposed: Erulipus fruhstorferi?=?Ainu grandisRen and Yuan, 2005, syn. nov. Two new species are described from China: Ainu linwenxini Nabozhenko & Ren, sp. nov. (Taiwan) and Ainu basifemoratum Nabozhenko & Ren, sp. nov. (Yunnan). Both the new species are closely related to A. sichuanumRen and Yuan, 2015. 相似文献
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《Journal of Asia》2020,23(2):516-528
The genus Laena Dejean, 1821 belongs to the subfamily Lagriinae, tribe Laenini. Four new species of this genus are described and illustrated from Sichuan under the following name: Laena ceratina Wei & Ren, sp. nov., Laena edentata Zhao & Ren, sp. nov. (from Sichuan and Qinghai), Laena latitarsia Wei & Ren, sp. nov. (from Sichuan and Yunnan) and Laena sufflofemora Wei & Ren, sp. nov.. A key to the known Laena species from Sichuan is provided. www.zoobank.org/urn:urn:lsid:zoobank.org:pub:8DBFD10F-F968-400C-846B-1C23E8DEC177. 相似文献
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Prediction of butterfly diversity hotspots in Belgium: a comparison of statistically focused and land use-focused models 总被引:1,自引:0,他引:1
Dirk Maes Marius Gilbert Nicolas Titeux Philippe Goffart Roger L. H. Dennis 《Journal of Biogeography》2003,30(12):1907-1920
Aim We evaluate differences between and the applicability of three linear predictive models to determine butterfly hotspots in Belgium for nature conservation purposes. Location The study is carried out in Belgium for records located to Universal Transverse Mercator (UTM) grid cells of 5 × 5 km. Methods We first determine the relationship between factors correlated to butterfly diversity by means of modified t‐tests and principal components analysis; subsequently, we predict hotspots using linear models based on land use, climate and topographical variables of well‐surveyed UTM grid cells (n = 197). The well‐surveyed squares are divided into a training set and an evaluation set to test the model predictions. We apply three different models: (1) a ‘statistically focused’ model where variables are entered in descending order of statistical significance, (2) a ‘land use‐focused’ model where land use variables known to be related to butterfly diversity are forced into the model and (3) a ‘hybrid’ model where the variables of the ‘land use‐focused model’ are entered first and subsequently complemented by the remaining variables entered in descending order of statistical significance. Results A principal components analyses reveals that climate, and to a large extent, land use are locked into topography, and that topography and climate are the variables most strongly correlated with butterfly diversity in Belgium. In the statistically focused model, biogeographical region alone explains 65% of the variability; other variables entering the statistically focused model are the area of coniferous and deciduous woodland, elevation and the number of frost days; the statistically focused model explains 77% of the variability in the training set and 66% in the evaluation set. In the land use‐focused model, biogeographical region, deciduous and mixed woodland, natural grassland, heathland and bog, woodland edge, urban and agricultural area and biotope diversity are forced into the model; the land use‐focused model explains 68% of the variability in the training set and 57% in the evaluation set. In the hybrid model, all variables from the land use‐focused model are entered first and the covariates elevation, number of frost days and natural grassland area are added on statistical grounds; the hybrid model explains 78% of the variability in the training set and 67% in the evaluation set. Applying the different models to determine butterfly diversity hotspots resulted in the delimitation of spatially different areas. Main conclusions The best predictions of butterfly diversity in Belgium are obtained by the hybrid model in which land use variables relevant to butterfly richness are entered first after which climatic and topographic variables were added on strictly statistical grounds. The land use‐focused model does not predict butterfly diversity in a satisfactory manner. When using predictive models to determine butterfly diversity, conservation biologists need to be aware of the consequences of applying such models. Although, in conservation biology, land use‐focused models are preferable to statistically focused models, one should always check whether the applied model makes sense on the ground. Predictive models can target mapping efforts towards potentially species‐rich sites and permits the incorporation of un‐surveyed sites into nature conservancy policies. Species richness distribution maps produced by predictive modelling should therefore be used as pro‐active conservation tools. 相似文献
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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