A global strategy to conserve biodiversity must aim to protect representative examples of all of the world's ecosystems, as well as those areas that contain exceptional concentrations of species and ...endemics. Although lacking the richness of tropical forests, deserts, tropical lakes, and subpolar seas all contain distinct species, communities, and ecological phenomena. We analyzed global patterns of biodiversity to identify a set of the Earth's terrestrial, freshwater, and marine ecoregions that harbor exceptional biodiversity and are representative of its ecosystems. We placed each of the Earth's ecoregions within a system of 30 biomes and biogeographic realms to facilitate a representation analysis. Biodiversity features were compared among ecoregions to assess their irreplaceability or distinctiveness. These features included species richness, endemic species, unusual higher taxa, unusual ecological or evolutionary phenomena, and the global rarity of habitats. This process yielded 238 ecoregions-the Global 200-comprised of 142 terrestrial, 53 freshwater, and 43 marine priority ecoregions. Effective conservation in this set of ecoregions would help conserve the most outstanding and representative habitats for biodiversity on this planet.
Aims We present the first global map of vascular plant species richness by ecoregion and compare these results with the published literature on global priorities for plant conservation. In so doing, ...we assess the state of floristic knowledge across ecoregions as described in floras, checklists, and other published documents and pinpoint geographical gaps in our understanding of the global vascular plant flora. Finally, we explore the relationships between plant species richness by ecoregion and our knowledge of the flora, and between plant richness and the human footprint - a spatially explicit measure of the loss and degradation of natural habitats and ecosystems as a result of human activities. Location Global. Methods Richness estimates for the 867 terrestrial ecoregions of the world were derived from published richness data of c. 1800 geographical units. We applied one of four methods to assess richness, depending on data quality. These included collation and interpretation of published data, use of species-area curves to extrapolate richness, use of taxon-based data, and estimates derived from other ecoregions within the same biome. Results The highest estimate of plant species richness is in the Borneo lowlands ecoregion (10,000 species) followed by nine ecoregions located in Central and South America with ≥ 8000 species; all are found within the Tropical and Subtropical Moist Broadleaf Forests biome. Among the 51 ecoregions with ≥ 5000 species, only five are located in temperate regions. For 43% of the 867 ecoregions, data quality was considered good or moderate. Among biomes, adequate data are especially lacking for flooded grasslands and flooded savannas. We found a significant correlation between species richness and data quality for only a few biomes, and, in all of these cases, our results indicated that species-rich ecoregions are better studied than those poor in vascular plants. Similarly, only in a few biomes did we find significant correlations between species richness and the human footprint, all of which were positive. Main conclusions The work presented here sets the stage for comparisons of degree of concordance of plant species richness with plant endemism and vertebrate species richness: important analyses for a comprehensive global biodiversity strategy. We suggest: (1) that current global plant conservation strategies be reviewed to check if they cover the most outstanding examples of regions from each of the world's major biomes, even if these examples are species-poor compared with other biomes; (2) that flooded grasslands and flooded savannas should become a global priority in collecting and compiling richness data for vascular plants; and (3) that future studies which rely upon species-area calculations do not use a uniform parameter value but instead use values derived separately for subregions.
Understanding patterns of biodiversity distribution is essential to conservation strategies, but severe data constraints make surrogate measures necessary. For this reason, many studies have tested ...the performance of terrestrial vertebrates as surrogates for overall species diversity, but these tests have typically been limited to a single taxon or region. Here we show that global patterns of richness are highly correlated among amphibians, reptiles, birds and mammals, as are endemism patterns. Furthermore, we demonstrate that although the correlation between global richness and endemism is low, aggregate regions selected for high levels of endemism capture significantly more species than expected by chance. Although areas high in endemism have long been targeted for the protection of narrow-ranging species, our findings provide evidence that endemism is also a useful surrogate for the conservation of all terrestrial vertebrates.
Large mammals often play critical roles within ecosystems by affecting either prey populations or the structure and species composition of surrounding vegetation. However, large mammals are highly ...vulnerable to extirpation by humans and consequently, severe contractions of species ranges result in intact large mammal faunas becoming increasingly rare. We compared historical (AD 1500) range maps of large mammals with their current distributions to determine which areas today retain complete assemblages of large mammals. We estimate that less than 21% of the earth's terrestrial surface still contains all of the large (>20 kg) mammals it once held, with the proportion varying between 68% in Australasia to only 1% in Indomalaya. Although the presence of large mammals offers no guarantee of the presence of all smaller animals, their absence represents an ecologically based measurement of human impacts on biodiversity. Given the ecological importance of large mammals and their vulnerability to extinction, better protection and extension of sites containing complete assemblages of large mammals is urgently needed.
Pinpointing and preventing imminent extinctions Ricketts, T.H; Dinerstein, E; Boucher, T ...
Proceedings of the National Academy of Sciences - PNAS,
12/2005, Letnik:
102, Številka:
51
Journal Article
Recenzirano
Odprti dostop
Slowing rates of global biodiversity loss requires preventing species extinctions. Here we pinpoint centers of imminent extinction, where highly threatened species are confined to single sites. ...Within five globally assessed taxa (i.e., mammals, birds, selected reptiles, amphibians, and conifers), we find 794 such species, three times the number recorded as having gone extinct since 1500. These species occur in 595 sites, concentrated in tropical forests, on islands, and in mountainous areas. Their taxonomic and geographical distribution differs significantly from that of historical extinctions, indicating an expansion of the current extinction episode beyond sensitive species and places toward the planet's most biodiverse mainland regions. Only one-third of the sites are legally protected, and most are surrounded by intense human development. These sites represent clear opportunities for urgent conservation action to prevent species loss.
Funding for conservation action to preserve vanishing species is limited, so finances have to be targeted at areas that are richest in biodiversity. The representation approach to biodiversity ...conservation, in which examples of all ecosystem and habitat types are preserved, is promoted. The Global 200 ecoregions represent terrestrial, freshwater, and marine major habitat types in each biogeographic realm. A detailed list of these regions summarized their approximate location and current conservation status. The boundaries of these regions are derived from intensive regional analyses of biodiversity patterns. Each ecoregion is rated in one of four categories of biological distinctiveness as well. Island ecoregions are projected to experience a wave of extinctions in the next 20 yr because of their fragility, sensitivity to competition from introduced species, and endemicity. The Global 200 list is an effective strategy for targeting biodiversity units and promoting ecosystem-level representation on a global scale, because it broadens the focus from species diversity to habitat diversity, ecological processes, evolutionary phenomena, and adaptations.
The world's forests are crucially important for both biodiversity conservation and climate mitigation. New forest status and forest change spatial layers using remotely sensed data have ...revolutionised forest monitoring globally, and provide fine-scale deforestation alerts that can be actioned in near-real time. However, existing products are restricted to representing tree cover and do not reflect the considerable spatial variation in the biological importance of forests. Here we link modelled biodiversity values to remotely sensed data on tree cover to develop global maps of forest biodiversity significance (based on the rarity-weighted richness of forest mammal, bird, amphibian and conifer species) and forest biodiversity intactness (based on the modelled relationship between anthropogenic pressures and community intactness). The strengths and weaknesses of these products for policy and local decision-making are reviewed and we map out future improvements and developments that are needed to enhance their usefulness.
In an unprecedented response to the rapid decline in wild tiger populations, the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg Declaration in November 2010, pledging ...to double the wild tiger population. We conducted a landscape analysis of tiger habitat to determine if a recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes can potentially support >10,000 tigers, almost thrice the current estimate. However, most core reserves where tigers breed are small and land‐use change in rapidly developing Asia threatens to increase reserve and population isolation. Maintaining population viability and resilience will depend upon a landscape approach to manage tigers as metapopulations. Thus, both site‐level protection and landscape‐scale interventions to secure habitat corridors are simultaneous imperatives. Co‐benefits, such as payment schemes for carbon and other ecosystem services, should be employed as strategies to mainstream landscape conservation in tiger habitat into development processes.
Ambitious biodiversity goals to protect 30% or more of the Earth’s surface by 2030 (30x30) require strategic near-term targets. To define areas that must be protected to prevent the most likely and ...imminent extinctions, we propose Conservation Imperatives—16,825 unprotected sites spanning ~164 Mha of the terrestrial realm that harbor rare and threatened species. We estimate that protecting the Conservation Imperatives would cost approximately US$169 billion (90% probability: US$146—US$228 billion). Globally, 38% of the 16,825 sites are either adjacent to or within 2.5 km of an existing protected area, potentially reducing land acquisition and management costs. These sites should be prioritized for conservation action over the next 5 years as part of a broader strategy to expand the global protected area network. The expansion of global protected areas between 2018 and 2023 incorporated only 7% of sites harboring range-limited and threatened species, highlighting a renewed urgency to conserve these habitats. Permanently protecting only 0.74% of land found in the tropics, where Conservation Imperatives are concentrated, could prevent the majority of predicted near-term extinctions once adequately resourced. We estimate this cost to be from US$29 billion to US$46 billion per year over the next 5 years. Multiple approaches will be required to meet long-term protection goals: providing rights and titles to Indigenous Peoples and Local Communities (IPLCs) conserving traditional lands, government designation of new protected areas on federal and state lands, and land purchase or long-term leasing of privately held lands.
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