Since about 1600, 486 animal species have been recorded extinct. This represents about 0.04 of all animal species so far described. In the same period, 600 plant species are known to have disappeared, about 0.25 of the total. These figures are much smaller than those of the Permian/Triassic and Cretaceous/Tertiary mass extinctions. One might therefore conclude that at present life on earth is at comparatively little risk of extinction. However, there is a growing body of data to show that the converse is true.
Resource Type: Journal PapersGeographical range is considered a good predictor of the levels of isozyme variation in plants. Widespread species, often consisting of historically larger and more continuous populations, maintain higher polymorphism and are less affected by drift, which tends to erode genetic variation in more geographically restricted species. However, widespread species occurring in small and disjunct populations may not fit this pattern. In this study we examined genetic variation in Pilgerodendron uviferum, a conifer endemic to temperate forests of southern South America.
Resource Type: Journal PapersThis synthesis focuses on estimates of biodiversity change as projected for the 21st century by models or extrapolations based on experiments and observed trends. The term “biodiversity” is used in a broad sense as it is defined in the Convention on Biological Diversity to mean the abundance and distributions of and interactions between genotypes, species, communities, ecosystems and biomes. This synthesis pays particular attention to the interactions between biodiversity and ecosystem services and to critical “tipping points” that could lead to large, rapid and potentially irreversible changes. Comparisons between models are used to estimate the range of projections and to identify sources of uncertainty. Experiments and observed trends are used to check the plausibility of these projections. In addition we have identified possible actions at the local, national and international levels that can be taken to conserve biodiversity. We have called on a wide range of scientists to participate in this synthesis, with the objective to provide decision makers with messages that reflect the consensus of the scientific community and that will aid in the development of policy and management strategies that are ambitious, forward looking and proactive.
Resource Type: ReportsThere is an urgent need to evaluate the status of groups of species for conservation purposes. A species' status is indicated by both its distribution and abundance, and the rate at which these components are changing. This information is scarce for many tropical forest species. We produced four measures of status based on locality and habitat data for 25 partridges and pheasants of Southeast Asia.
Resource Type: Journal PapersStipitate hydnoid ('tooth') fungi are considered to be threatened throughout much of central and northern Europe. In response to concern about the status of these fungi in the UK, a Biodiversity Action Plan has been developed for 14 species in this group. As a first step towards implementation of this plan, a number of surveys have been initiated, to determine the current status and distribution of hydnoid fungi. An overview of the results of these surveys is described. A series of distribution maps are presented, based on a compilation of early records and the results of a recent field survey in Scottish coniferous forests. The difficulties of interpreting early records are discussed, with particular reference to the taxonomie confusion that has surrounded this group of fungi. Although available data provide little evidence for decline of hydnoid fungi, a number of species display very restricted distributions within Scotland. The recent discovery of several species new to Britain emphasises the need for further field surveys to define the current status of these fungi with greater accuracy.
Resource Type: Journal PapersThe third edition of Global Biodiversity Outlook (GBO-3) summarizes the latest data on status and trends of biodiversity and draws conclusions for the future strategy of the Convention. GBO-3 is based on a range of information sources, including National Reports, biodiversity indicators information, scientific literature, and a study assessing biodiversity scenarios for the future.
Resource Type: ReportsRuff breeding populations have declined widely and in all habitats across temperate Eurasia. Of an estimated population of 2.2-2.8 million birds, 98% are now confined to habitats in the Arctic tundra.
The emerging picture is that the population has shifted northwards and eastwards and has retreated from the wet grassland habitats formerly occupied along the southern edges of its range. It is suggested that the causes are probably of a global nature and may be linked with climate change. It is unclear whether the total population has declined or only shifted north and east. More co-ordinated and systematic monitoring of breeding and wintering populations will be necessary before a full understanding of these changes can be reached.
Resource Type: Journal PapersThe effects of Pleistocene glaciations on the genetic characteristics of the most austral conifer in the world, Pilgerodendron uviferum, were analysed with specific reference to the hypothesis that the species persisted locally in ice-free areas in temperate South America.
Results indicated that Pilgerodendron populations are highly monomorphic, probably reflecting past population bottlenecks and reduced gene flow. Southernmost populations tend to be the least genetically variable and were therefore probably more affected by glacial activity than northern ones. Populations located outside ice limits seem to have been isolated during the glacial period. The presence of centres of genetic diversity, together with the lack of a significant correlation between genetic and geographical distances and the absence of geographical patterns of allelic frequencies at most analysed alleles, may indicate that Pilgerodendron did not advance southward after the last glaciation from a unique northern refugium, but spread from several surviving populations in ice-free areas in Patagonia instead.
Resource Type: Journal PapersSpoon-billed Sandpiper Eurynorhynchus pygmeus is classed as globally Vulnerable, based on the only available population estimate, made in 1977, of 2,000-2,800 pairs. Surveys for breeding Spoon-billed Sandpipers were carried out in summer 2000 on the Anadyr estuary coast, the Chukotka autonomous region, Russia. Although six new breeding sites were found, only 16-17 breeding males/pairs were recorded on the northern coast of the Anadyr estuary and five males/pairs on the southern coast and more southerly lagoons. These numbers were much lower than expected, and the species was not recorded in several apparently suitable areas.
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