Four desert waters: Setting arid zone wetland conservation priorities through understanding patterns of endemism

Long-lasting surface water in arid-lands provide oases for aquatic biota, but their values as biological refugia have rarely been assessed. This study identified and mapped permanent natural wetlands across the Eastern Lake Eyre Basin in Australia and classified them into four types: riverine waterholes, rockholes, discharge springs and outcrop springs. Waterholes are the most widespread and numerous source of lasting water, while springs and rockholes are confined to relatively discrete clusters. The characteristics of each wetland type are summarised, and their biological values compared by examining various scales of endemism for vascular plant, fish and mollusc species. Discharge springs contain an exceptional concentration of endemic species across all three lifeforms at a range of scales. Waterholes are critical drought refugia for native fish species that also utilise a vast network of ephemeral streams during and after floods. Rockholes and outcrop springs do not contain any known specialised endemics, although the latter have disjunct populations of some plants and fish. The existing knowledge of antiquity, connectivity and habitat differentiation of the wetland types is compiled and their role in determining biological endemism is discussed. Exotic fish are a major conservation issue, the recovery of the discharge springs should be paramount, and the intact network of permanent waterholes should be preserved. A focus on endemism, combined with an understanding of the biogeographical processes underlying the observed patterns provides an effective and systematic approach to setting priorities for regional biodiversity conservation.     

Factoring species, non-species values and threats into biodiversity prioritisation across the ecoregions of Africa and its islands

Biodiversity in Africa, Madagascar and smaller surrounding islands is both globally extraordinary and increasingly threatened. However, to date no analyses have effectively integrated species values (e.g., richness, endemism) ‘non-species’ values (e.g., migrations, intact assemblages), and threats into a single assessment of conservation priorities. We present such an analysis for the 119 ecoregions of Africa, Madagascar and smaller islands. Biodiversity is not evenly distributed across Africa and patterns vary somewhat among taxonomic groups. Analyses of most vertebrates (i.e., birds, mammals, amphibians) tend to identify one set of priority ecoregions, while plants, reptiles, and invertebrates highlight additional areas. ‘Non-species’ biological values are not correlated with species measures and thus indicate another set of ecoregions. Combining species and non-species values is therefore crucial for assembling a comprehensive portfolio of conservation priorities across Africa. Threats to biodiversity are also unevenly distributed across Africa. We calculate a synthetic threat index using remaining habitat, habitat block size, degree of habitat fragmentation, coverage within protected areas, human population density, and the extinction risk of species. This threat index is positively correlated with all three measures of biological value (i.e., richness, endemism, non-species values), indicating that threats tend to be focused on the region’s most important areas for biodiversity. Integrating biological values with threats allows identification of two distinct sets of ecoregion priority. First, highly imperilled ecoregions with many narrow endemic species that require focused actions to prevent the loss of further habitat leading to the extinction of narrowly distributed endemics. Second, less threatened ecoregions that require maintenance of large and well-connected habitats that will support large-scale habitat processes and associated area-demanding species. By bringing these data together we can be much more confident that our set of conservation recommendations serves the needs of biodiversity across Africa, and that the contribution of different agencies to achieving African conservation can be firmly measured against these priorities.     

Endemism and evolutionary history in conflict over Madagascar’s freshwater conservation priorities

Regional-scale biodiversity indicators provide important criteria for the selection of protected areas in conservation, but their application is often hindered by a lack of taxonomic knowledge. Moreover, different indicators include different types of information, sometimes leading to divergent conservation priorities. Madagascar tops the world list of biodiversity hotspots and much conservation effort has been directed toward its threatened plants and vertebrates. In contrast, its highly diverse freshwater invertebrate fauna has received comparatively little conservation attention. We conducted an inventory of Malagasy adephagan water beetles (Coleoptera, Dytiscidae, Noteridae, Gyrinidae, Haliplidae) using a combined morphological and molecular approach. In total, 2043 beetles from 153 sites were sequenced for cytochrome oxidase subunit I (cox1), and species delimitation was carried out using the coalescent-based GMYC model. Phylogenetic relationships of the resulting entities were established using cox1 combined with partial 16S rRNA and 28S rRNA sequences. Ten national parks were assessed for their species richness, phylogenetic diversity (PD) and endemism. We were particularly interested in the contribution of endemic species to PD. Congruence between molecular and taxonomic identifications was high (91%), with 69% of sampled species endemic to Madagascar. Interestingly, we found that PD at a site was negatively correlated to the proportion of endemic species, most likely because endemics are the result of recent radiations with relatively little branch-length contribution to the measure of PD. This suggests that ranking sites for conservation priority based solely on PD potentially disfavor endemic species by underrating areas where the evolutionary process is most active.     

Commonness and rarity in plants with special reference to the Sheffield flora part IV: A European context with particular reference to endemism

With respect to reasons for commonness and rarity, an attempt is made to compare the flora of the Sheffield region with that of Europe as a whole. Land use appears to exert a critical effect on species abundance in both floras. However, European endemics, a grouping poorly represented in the Sheffield region and indeed in N Europe, form a very different class of rare species. Unlike the rare species of the Sheffield region, which are particularly associated with primitive families (sensu Sporne, 1980), European endemics tend to be found in advanced families, the very families with the greatest proportion of common species. Thus, while the main factors controlling abundance in N Europe appear to be essentially similar to those operating in the Sheffield region, additional processes related to endemism must be taken into account in S Europe. Implications of these results for conservation policy are reviewed.     

Regional priority setting for rare species based on a method combining three criteria

We propose a method to establish regional-level priorities for plant species that is based on three criteria. These involve two main criteria associated with species rarity, (a) small range size and thus regional responsibility and (b) low population numbers and thus local rarity, and a third criteria associated with habitat vulnerability to distinguish species currently threatened by human activities. Application of the method shows how the three criteria can be objectively and readily quantified (using a system of equal numbers of ranks) and combined into a hierarchy of priorities. We show how this can be done by using regional responsibility as a first order priority followed successively by local rarity and habitat vulnerability. Since the criteria are closely associated with rarity, this method is easily understandable for decision makers. We illustrate the application of the method to plants (a species rich group) at two regional scales where the objectives are different. If adapted to the availability of different types of data, the three criteria could be used to produce comparable lists in different countries and regions.     

Grouping and prioritization of vascular plant species for conservation: combining natural rarity and management need

National and International Red Lists and Legal Acts specify species with conservation needs, mainly on the basis of personal experiences. For effective conservation we need scientifically justified prioritization and grouping of these species. We propose a new combined approach where species are grouped according to the similar activities needed for their conservation. We used the national list of vascular plant species with conservation need for Estonia (301 species), and linked these species to eight qualitative conservation characteristics, four reflecting natural causes of rarity (restricted global distribution; restricted local distribution within a country; always small populations; very rare habitat type), and four connected with nature management (species needing the management of semi-natural grasslands; species needing local disturbances like forest fires; species needing traditional extensive agriculture; species which may be threatened by collecting). Only one positive association occurred among the characteristics - between restricted local distribution and small size of populations. Thus, natural causes of rarity and management aspects are not overlapping, and both should be used in conservation activities. Species grouping by different conservation characteristics allows one to focus on species groups with similar conservation needs instead of individual species. Prioritization of species with conservation needs can be based on the number of conservation characteristics that are associated with a particular species. Our prioritization did not correlate with the categories of the national Red Data Book, but a positive association was found with legal protection categories. The legislation, however, covers only the natural causes of rarity. We propose a new combined approach for plant species’ conservation planning that starts by considering human induced rarity and progresses through to natural rarity causes.     

Importance of cryptic species for identifying ‘representative’ units of biodiversity for freshwater conservation

Nested systems of biodiversity classification are commonly used for designating protected area networks in terrestrial and marine realms. Whilst terrestrial-style protected areas are largely inappropriate for freshwater systems, the concepts of ‘representative’ biodiversity and ‘complementarity’ can be borrowed for freshwater conservation. Cryptic species are commonly found in freshwater macroinvertebrates and fish, and most have restricted distributions relative to the described conglomerate ‘species’. This indicates that ‘representative’ and therefore ‘complementary’ units of freshwater biodiversity may be smaller than previously appreciated. Using recently detected cryptic species in atyid shrimps from eastern Australia (Atyidae: Paratya australiensis, Caridina mccullochi and C. indistinca), we tested predictions about regional patterns of cryptic assemblage structure, endemism and Phylogenetic Diversity (PD) at the river scale, and discussed their implications for freshwater conservation. Patterns of distribution in these cryptic shrimp species largely corresponded with published distributional patterns of cryptic species in several freshwater fish in eastern Australia, and indicated the presence of four putative ecoregions within a previously recognised freshwater fish province (Eastern Province). However, some rivers had pronounced cryptic endemism, suggesting that rivers may not be ‘representative’ of one another’s biodiversity even within ecoregions. PD and endemism were largely correlated with one another, as endemics typically co-occurred with widespread species at the river scale. This study indicates that cryptic species can contribute to defining patterns of biodiversity at nested spatial scales that may be important for freshwater conservation.     

Plant endemism and natural protected areas in the peninsula of Baja California, Mexico

The Peninsula of Baja California, Mexico has long been recognized as a hotspot for plant richness and endemism. However, its extraordinary diversity is not adequately protected by the existing protected areas. We analyzed the distribution of the endemic vascular flora of the peninsula, and its presence or absence in protected areas. We also identified regions with greater numbers of endemic species not currently under protected status. The families Asteraceae, Cactaceae, and Fabaceae alone contain 40% of the endemic species. All the peninsular species within the Begoniaceae, Thymeliaceae, Araliaceae and Hippocastanaceae are endemic. Of the total number of endemic taxa in the region, 76.4% are present within protected areas. The endemic genera Adenothamnus, Carterothamnus, Faxonia, and Ornithostaphylos are entirely absent from protected areas. Of the 567 endemics found in protected areas 75 represent varieties or subspecies Of the 175 not found in protected areas 21 are varieties or subspecies. A gap analysis identified that the areas with the highest number of unprotected endemic species are in the Mediterranean-type ecosystems of the north-west part of the peninsula and in the deciduous dry tropical communities of the cape region at the southernmost tip of Baja California. Our findings suggest that it is necessary to create several protected areas along the peninsula for the successful conservation of rare and endemic taxa These new areas should encompass a latitudinal gradient of biogeographical units (including Mediterranean communities and montane habitats of the Sierras) along the peninsula.     

Distribution patterns, range size and niche breadth of Austrian endemic plants

Endemic species are not a uniform group in terms of range size, habitat preferences, and ecological plasticity. Based on a recent inventory of endemic vascular plant species in Austria, we analysed distribution patterns, altitudinal distribution and habitat preferences of endemic species and analysed the correlation of range size and niche breadth. The inventory includes 103 vascular plant taxa (species and subspecies) endemic to Austria.Grid cells (cell size ca. 35 km²) with highest taxon numbers (max. 25 taxa) are limited to the Northeastern Calcareous Alps, whereas highest numbers of acidophilous endemics occur in the easternmost high-mountain chains of the Central Alps. The majority of endemics (61 taxa; 59.2%) are found on calcareous bedrock, 6 taxa (5.8%) on intermediate substrates, and 29 (28.2%) on siliceous bedrock. The range size of endemic vascular plant taxa is strongly skewed towards very narrow distributions – 45 taxa are restricted to <20 grid cells. Average range sizes differ markedly between endemics of different broad habitat types, endemics of habitats with limited and patchy distribution (serpentine vegetation, dry grassland) having the smallest ranges.The altitudinal distribution of endemic plant taxa peaks at high altitudes, in the subalpine and lower alpine altitude belt. Below the tree line, endemics predominantly colonize extra- and azonal dry or wet habitats, whereas above the tree line, zonal alpine grassland and azonal vegetation types (scree, rocks, snowbeds) are equally essential to the endemic flora. Niche breadth of endemics is positively, however moderately, correlated with range size. This correlation is stronger for the altitudinal distribution than for the number of habitats colonized.The distribution patterns and ecology of endemics differ considerably from overall biodiversity patterns and must be addressed appropriately in conservation strategies. Small niche-breadths and the specific habitat requirements of endemics of very localized distribution render these taxa highly vulnerable to climate change.     

Micro-hotspot determination and buffer zone value for Odonata in a globally significant biosphere reserve

Reserves are frequently constrained in design and size by various financial, social or political factors. Maintenance of existing reserves must therefore rely on strategic management practices, and prioritization of conservation activities within them. Identification of global and regional hotspots have been effective for prioritizing conservation activities. Yet, identification of micro-hotspots, or overlapping areas of endemic and rare species that are under threat at the landscape scale, have largely been ignored. From a reserve management point of view, knowledge of critical micro-hotspots within a reserve, are focal points for directing cost effective, conservation initiatives, especially removal of invasive alien plants which are a major threat to biodiversity.Using diversity patterns of dragonfly assemblages, many endemic and threatened, within a biosphere reserve located in the core of a global biodiversity hotspot, we investigated the concept of micro-hotspots. As biosphere reserves contain zones with varying degrees of anthropogenic impact, we also investigated the value of buffer and transition zones for complementing the dragonfly fauna of the reserve core. We found a distinct micro-hotspot within the protected core zone which shows concordance for both endemism and species richness. We conclude that focused conservation actions to remove invasive alien plants within this micro-hotspot would help insure its continued integrity. Furthermore, while there is greater habitat degradation within the buffer and transition zones, they support many additional species, but not those necessarily endemic or threatened. The complementary value of buffer and transition zones therefore lies in increasing habitat heterogeneity and species richness of the whole reserve.     

Multiple diversity measures to identify complementary conservation areas for the Baja California peninsular cacti

The Baja California Peninsula is home to 85 species of cacti, of which 54 are endemic, highlighting its importance as a cactus diverse region within Mexico. Many species are under threat due to collection pressure and habitat loss, but ensuring maximal protection of cacti species requires a better understanding of diversity patterns. We assessed species richness, endemism, and phylogenetic and morphological diversity using herbarium records and a molecular phylogeny for 82 species of cacti found in the peninsula. The four diversity measures were estimated for the existing nature reserve network and for 314 hexagrids of 726 km². Using the hexagrid data, we surveyed our results for areas that best complement the current protected cacti diversity in the Baja California Peninsula. Currently, the natural reserve network in Baja shelters an important amount of the cacti diversity (74% of the species, 85.9% of the phylogenetic diversity, 76% of endemics and all the growth forms). While species richness produced several solutions to complement the diversity protected, by identifying priority species (endemic species with high contribution to overall PD) one best solution is reported. Three areas (San Matías, Magdalena and Margarita Islands and El Triunfo), selected using species richness, PD and endemism, best complement the diversity currently protected, increasing species richness to 89%, PD to 94% and endemism to 89%, and should be considered in future conservation plans. Two of these areas could be included within nature reserves already established.     

A large-scale conservation perspective considering endemic fishes of the North American plains

Regions with unique habitats often harbor endemic taxa associated with temporally stable habitats. We identified such habitats that sustain endemic fishes in the plains of North America. We also summarized threats to their conservation and identified remnant habitats that still harbor endemic fishes (refuges) based on post-1989 surveys. Major springs, smaller, spring-fed streams, larger rivers, and euryhaline habitats were associated with a total of 49 endemics. Endemism was attributable to climatic refugia associated with each habitat type and dispersal limitation among major river drainages and springs. Forty-one endemic fishes (84%) were declining or extinct. Dewatering, habitat fragmentation, and habitat degradation were main causes of declines, often present together. Pollution and non-native species were also threats in many cases. Evidence for 53 existing refuges was found. We considered 34 refuges to be “high-quality” because they harbored three or more endemics. Twenty of these (those with available data) maintained consistent streamflow regimes for at least 50 years up to 2009. Case studies suggest high stream length, more natural flow regimes, and fewer direct human impacts are features of high-quality refuges, but extinction thresholds are unquantified and extinction debts of refuges are unknown. Limited information on past extinctions suggests drought, a natural feature of the plains, combines with other threats to eliminate remnant endemic populations. Long-term conservation planning requires identification, protection, and restoration of high-quality refuges to reduce extinction risk, especially during future drought periods. Planning should be integrated with regional water resource planning, given scarcity of water in the region.     

Freshwater crabs and the biodiversity crisis: Importance, threats, status, and conservation challenges

Freshwater ecosystems in the tropics host a diverse endemic fauna including freshwater crabs, but the rapid loss and deterioration of habitat means that many species are now under imminent threat. Studies on freshwater fish and amphibians suggest a third to half of the species in some tropical freshwaters is either extinct or endangered, but the status of the freshwater crabs is not known. Freshwater crabs, with 1280 species, represent one-fifth of all the World’s brachyurans. We therefore undertook a comprehensive IUCN Red List assessment of the freshwater crabs, which was the first time that such a study had been attempted on a global scale for any group of freshwater invertebrates. The conservation status of all known species from the Americas, Africa, Europe, Asia, and Australasia revealed unexpectedly high threat levels. Here we show that about one-sixth of all freshwater crab species have an elevated risk of extinction, only one-third are not at-risk, and although none are actually extinct, almost half are too poorly known to assess. Out of 122 countries that have populations of freshwater crabs, 43 have species in need of protection. The majority of threatened species are restricted-range semi-terrestrial endemics living in habitats subjected to deforestation, alteration of drainage patterns, and pollution. This is illustrated with a case study of one such species found in Singapore. This underlines the need to prioritize and develop conservation measures before species decline to levels from which they cannot recover. The proportion of freshwater crabs threatened with extinction is equal to that of reef-building corals, and exceeds that of all other groups that have been assessed except for amphibians. These results represent a baseline that can be used to design strategies to save the World’s threatened freshwater crab species.     

Distribution and protected area coverage of endemic taxa in West Africa’s Biafran forests and highlands

The forests and highlands along the southern portion of the Nigeria-Cameroon border and on the island of Bioko have long been recognized as being biologically diverse. This region (referred to as the Biafran forests and highlands) is a center of endemism for a wide variety of taxa including, but not limited to, primates, anuran amphibians, birds, freshwater fish, butterflies, dragonflies, and trees. Though these groups have diverse distributions, conservation efforts have to date largely been focused on lowland areas. We conducted a GIS-based analysis of point locality records for three groups characterized by high endemism (primates, anuran amphibians, birds) in order to examine both their spatial and altitudinal distribution throughout the study area. We also evaluated the distribution of existing and potential protected areas relative to highland areas and the distribution of endemics. Our analysis suggests that the existing protected area system provides poor coverage of montane habitats and their associated endemic taxa. Complementarity analysis suggests that, if the protected area network were expanded to include a small number of highland sites, coverage of endemic taxa could be significantly improved. Many of these important highland sites are currently under intense pressure from habitat loss and hunting. If the full range of biodiversity present in the Biafran forests and highlands is to be preserved, new protected areas should be gazetted that take the varied distributions of the regions endemic taxa into account.     

A method for siting parks and reserves with special reference to Columbia and Ecuador

Many tropical countries contain large numbers of species with small geographical ranges, here, for convenience, termed endemics. South America, for example, harbours 440 endemic land birds having ranges of less than 50 000 km². These comprise about a quarter of the terrestrial avifauna of the continent. Such species are exceptionally vulnerable to deforestation and their preservation will require siting future parks or reserves in just the right places. Using Colombia and Ecuador as an illustration, we describe a simple procedure for locating areas of concentrated endemism that would be optimal for future protection. Unfortunately, there is little correspondence between the points of maximal endemism and the locations of existing and projected reserves in the two countries. The advantages and limitations of using satellite photos for habitat evaluation in centres of endemism are also discussed.     

Patterns of rarity and taxonomic group size in plants

The objective of this research is to examine the extent to which phylogenetic and geographical drivers of rarity may interact to help us better predict distributions of rare taxa. This information is useful to conservation biologists when considering plans for the effective capture of biological diversity within reserve systems. We use 33 floras, distributed globally among five biomes, to assess pattern of rarity across taxonomic group size for plants. We show that small plant families (1-10 taxa) contain consistently fewer rare taxa than expected, while rare plants are proportionately over-represented in large plant families (>100 taxa). We also examine the distribution of species within families. The degree to which species are inequitably distributed among families varied systematically across floristic biomes. Mediterranean floras, in particular, are characterized by a greater than expected fraction of their species pool concentrated within large families, suggesting a high propensity for rarity simply by virtue of having a higher proportion of their constituent taxa within groups with a high likelihood of rarity. Finally, an analysis of a suite of floras using a common system of identifying rarity shows that the fraction of species within floras that are rare is predicted both by flora size and by a general metric (the Gini coefficient) of inequality among family sizes. Together, these patterns suggest a high degree of predictability in the distribution of rarity in plants that may reflect underlying natural speciation and extinction processes.     

Analysis of the distribution of endemic and rare arthropods in high endemism areas of Algarve-South Portugal

The study of several arthropod groups in high endemism areas (HEA) of Algarve, the Southernmost province of Portugal, has revealed endemic species and species not yet recorded for the Portuguese fauna. The list includes 3 species of Isopoda endemic to Algarve, to Portugal or to the Iberian Peninsula, 2 species new to Portugal and 2 species new to the Iberian Peninsula; 2 species of Pseudoscorpiones not yet cited to Portugal; 11 species of Pauropoda new to Portugal, including one new species probably endemic; 15 species of Collembola endemic to the Portuguese or to the Iberian Peninsula faunas (Gama et al. 1997) and 37 species and 5 subspecies of Staphylinidae endemic to Algarve.With the exception of Collembola, which have been studied by us, the remaining groups have been submitted for study to several specialists.These findings heighten the biological richness of these areas of high endemism in terms of conservation of biological diversity. The authors draw attention to the necessity to preserve or restore the biological value of these areas, encouraging the adoption of protective measures and the creation of research programmes that include the implementation of taxonomic studies and co-operation between taxonomists and ecologists in order to preserve the biodiversity of these areas.     

Avian conservation priorities in a top-ranked biodiversity hotspot

Rio de Janeiro state in Brazil has one of the most diverse and most endangered avifaunas in the continental Americas. Many of these endangered birds are endemic to the Atlantic Forest biodiversity hotspot, and some even endemic to Rio de Janeiro itself. As with all other forested hotspots, little original forest remains. Much of that is outside formal protected areas and faces the risk of deforestation. These factors create special circumstances for setting conservation priorities — ones common to hotspots in general — but typically not to many conservation priority setting exercises.We mapped the distribution of the remaining habitat for the 189 birds in Rio de Janeiro state that are officially endangered and/or endemic to the Atlantic Forest. Using those habitat maps, we calculated the amount of habitat currently within protected areas for each species. We then prioritized all non-protected parts of the state for their avian conservation value and their potential contribution to a comprehensive protected area system. This analysis identified 10% of the remaining unprotected part of the state as the highest priority for avian conservation. We further highlight specific locations where conservation actions could create a more comprehensive protected area system for the avifauna of Rio de Janeiro state.     

Cryptic genetic diversity in “widespread” Southeast Asian bird species suggests that Philippine avian endemism is gravely underestimated

Mistakenly classifying morphologically cryptic endemic species as populations of widespread species potentially interferes with the conservation of biodiversity because undetected endemics that are imperilled may lack appropriate protection. It also impedes the reconstruction of the evolutionary history of a taxon by obscuring the number and distributional limits of species. Here, we present genetic and phylogenetic evidence corroborated by morphology that Philippine populations of seven widespread, non-migratory passerine birds might represent unrecognized, distinct species. An extrapolation based on this finding suggests that the proportion of endemic bird species in the Philippines could be much higher than currently estimated. This high degree of cryptic diversity in a well-studied, volant taxon implies that large numbers of unrecognized species can be expected in less thoroughly studied groups. We predict that genetic investigations of insular populations of widespread species will frequently reveal unrecognized island endemics, and because of the vulnerability of island habitats and their biota, these taxa may be particularly susceptible to extinction.     

The biodiversity of the Albertine Rift

The Albertine Rift is one of the most important regions for conservation in Africa. It contains more vertebrate species than any other region on the continent and contains more endemic species of vertebrate than any other region on mainland Africa. This paper compiles all currently known species distribution information for plants, endemic butterfly species and four vertebrate taxa from the Albertine Rift. The literature on fish species richness and endemism is also reviewed to assess the importance of the larger lakes in the Rift for conservation. We use data from 38 protected and unprotected areas to prioritise sites within the Albertine Rift for conservation based upon their numbers of endemic and globally threatened species. Virunga and Kahuzi Biega National Parks and Itombwe Massif in Democratic Republic of Congo, Bwindi Impenetrable and Kibale National Parks in Uganda, and Nyungwe National Park in Rwanda rank highest in terms of numbers of both endemic and globally threatened species. Six conservation landscapes are described that include most of these sites and it is argued that a focus on these landscapes may be a more holistic method to ensure the safety of the priority areas of the Albertine Rift.