Search results for "Critically endangered"
showing 10 items of 32 documents
Conservation priorities for harlequin frogs (Atelopus spp.) of Peru
2005
Populations of harlequin frogs Atelopus are declining throughout their geographical range. In Peru six of the 11 nominally described species are Critically Endangered, and there are at least 17 undescribed additional forms (all representing apparently distinct species), the conservation status of which is unknown. Most Atelopus taxa in Peru have relatively small geographical ranges, some known only from single populations, and have only a limited chance of survival. Conservation will require: (1) improvement of the faunistic and taxonomic knowledge of the genus, (2) field surveys, including in remote areas, (3) assessment of all species and populations for chytridiomycosis and research on t…
Czerwona lista porostów zagrożonych na Śląsku Opolskim i Górnym Śląsku [Red List of threatened lichens in Opole Silesia and Upper Silesia]
2014
The thirth regional list of threatened and allied fungi is presented. The list is a result of investigation studies in Opole Silesia and Upper Silesia in S Poland. The status of threat to the lichen and allied fungi species used has been determined according to the IUCN Red List Categories in version 3. l (2001). The data obtained were compared with historical ones. While assigning given lichen species to suitable categories of threat the geographic criterium of their occurrence ranges was accepted because most source data from the study area concerns the distribution and frequency of species. The Red List includes 536 taxa of lichens, lichenicolous and saprobic fungi, which constitute 72.9…
Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora
1998
ABSTRACT Cytisus aeolicus Guss, is an endemic plant restricted to the isles of Vulcano, Stromboli and Alicudi in the Aeolian archipelago. All known populations were assayed for genetic variability using enzyme polymorphism. Allozyme variation at 16 loci coding for 10 enzyme systems was examined. The great majority of loci turned out to be monomorphic or fixed heterozygous. The observed genetic depauperation is indicative of historical factors, such as the bottleneck effect associated with migration, and the founder effect in population re-establishment. The low genetic diversity is largely partitioned within rather than among populations, indicating that extant populations have not been est…
A report on the conservation status of segetal weeds in Tajikistan
2014
Summary Intensification of agriculture has significantly diminished the populations of segetal weeds worldwide in recent decades. Remarkable changes to the entire flora and vegetation of man-made habitats are being observed in agroecosystems. The present study analyses, for the first time, the threat status of segetal weeds in Tajikistan. A group of 871 weed species were evaluated against IUCN criteria. The assessment of threat status revealed that 214 weed taxa have to be regarded as threatened in Tajikistan, including 18 endemic and four subendemic plants. Five species have been classified as extinct, 27 as critically endangered, 27 as endangered, 39 as vulnerable, 34 as near threatened a…
Characterization of 10 trinucleotide microsatellite loci in the Critically Endangered Pyrenean yam Borderea chouardii (Dioscoreaceae)
2003
The low levels of allozymic variability found in the Critically Endangered Borderea chouardii prompted us to develop microsatellite markers to assess the genetic variability and population structure for the adequate conservation management of this species. A (CTT) n enriched partial genomic library was constructed. Ten polymorphic microsatellite loci were isolated from it, rendering 51 alleles in 47 individuals analysed. The allelic pattern observed for all of the loci with more than two alleles suggests that B. chouardii is tetraploid.
On the verge of extinction: genetics of the critically endangered Iberian plant species, Borderea chouardii (Dioscoreaceae) and implications for cons…
2005
Borderea chouardii is a relictual and dioecious, strictly sexually reproducing, long-living geophyte of the Dioscoreaceae family. Previous biological and demographic studies have indicated the existence of a uniformly distributed panmictic population of this taxon at the southernmost Spanish pre-Pyrenean mountain ranges where it occurs in rather inaccessible crevices of a single limestone cliff. However, individuals of B. chouardii are spatially subdivided into two subpopulations located, respectively, on the upper and lower parts of the cliff, and vertically separated 150 m. Because of its extreme rarity, B. chouardii was the first Iberian taxon to have a specific conservation plan and has…
Development of microsatellite markers for the critically endangered Limonium dufourii (Girard) Kuntze (Plumbaginaceae)
2002
Limonium dufourii is an endemic plant from the eastern Mediterranean coast of Spain with a triploid chromosome number and apomictic reproduction. We have isolated and characterized 13 polymorphic microsatellite loci from an enriched library in order to investigate its population genetic structure. Simple sequence repeat (SSR) loci were screened in 120 individuals from the six extant populations of this species. They show an average of 5.76 alleles per locus, ranging from 2 to 18, with seven loci exhibiting heterozygosities larger than 0.60. Three loci present one single allele in each individual, whereas one locus presents three alleles in every individual analysed.
Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)
2007
14 páginas, 5 figuras, 2 tablas.
Reproductive conflict delays the recovery of an endangered social species
2008
1. Evolutionary theory predicts that individuals, in order to increase their relative fitness, can evolve behaviours that are detrimental for the group or population. This mismatch is particularly visible in social organisms. Despite its potential to affect the population dynamics of social animals, this principle has not yet been applied to real-life conservation. 2. Social group structure has been argued to stabilize population dynamics due to the buffering effects of nonreproducing subordinates. However, competition for breeding positions in such species can also interfere with the reproduction of breeding pairs. 3. Seychelles magpie robins, Copsychus sechellarum, live in social groups w…
Living on the edge: assessing the extinction risk of critically endangered Bonelli’s eagle in Italy
2012
Background: The population of Bonelli’s eagle (Aquila fasciata) has declined drastically throughout its European range due to habitat degradation and unnatural elevated mortality. There are less than 1500 breeding pairs accounted for in Europe, and the species is currently catalogued as Critically Endangered in Italy, where the 22 territories of Sicily, represent nearly 95% of the entire Italian population. However, despite national and European conservation concerns, the species currently lacks a specific conservation plan, and no previous attempts to estimate the risk of extinction have been made. Methodology/Principal Findings: We incorporated the most updated demographic information ava…