A reduction in forest area should result in a reduction of its number of species and, moreover, do so in a characteristic way according to the familiar species-area relationship. Brooks, Pimm & Collar (1997) applied this formula to the losses in forest area in the Philippines and Indonesia. Independently derived totals of the number of endemic bird species that are threatened with extinction broadly agree with these predicted losses. In some cases, however, predicted losses overestimate or underestimate the actual numbers of threatened species.Resource Type: Journal Papers
Small local hunting communities in Siberia are very distant from any governmental control. Hunted waterbird species, including globally and regionally threatened species, rely for their well-being on the self regulation of remote hunting communities. Interviewed hunters showed a profound knowledge of Baikal Teal, its population status, and the causes of their past decline. Whether the knowledge is shared by other communities in the region and beyond in Northern Siberia needs verification.
A table is provided of 122 bird species with restricted breeding distributions and for which Nepal may hold significant populations. Habitat threats and population changes are detailed for 33 species for which Nepal may be especially important. The vital importance of Nepal's forests to Nepal's avifauna is emphasised.Resource Type: Journal Papers
This study demonstrates the utility of carbon isotope discrimination in describing genetic adaptation to arid environments, although it is probably most useful in detecting differentiation when the strategy of the species under investigation is to increase water use efficiency, rather than drought-avoidance. The results suggest that populations on the eastern and western sides of the Andes should be treated as separate management units for the purposes of conserving the genetic resource of this species.Resource Type: Journal Papers
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 Papers
The 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 Papers
We made a complete survey of all the extant populations in Djibouti and to collect samples for genetic analysis with a view conserving the palm for the future.
Our survey revealed that there were a total of 314 adults, 20 juveniles, 134 rosettes, 210 small rosettes (more than 6 leaves) and 465 seedlings (<3 leaves) living in the Bankouale area of Djibouti. These are distributed unequally amongst three valley systems. 65% of the adults, 85% of the juveniles, 75% of the rosettes, 76% of the small rosettes, and 93 % of the seedlings were found in the Bankouale valley.
The number of environmental variables used during modelling could affect the outcome, but we found no correlation between these and our estimates of extinction risk in global samples. Although further investigation is needed, it is unlikely to result in substantially reduced estimates of extinction. Anthropogenic climate change seems set to generate very large numbers of species-level extinctions.Resource Type: Journal Papers
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