Search results for "Danger"
showing 10 items of 264 documents
RAPD differentiation between Borderea pyrenaica and B. chouardii (Dioscoreaceae), two relict endangered taxa
2001
As currently circumscribed, the genus Borderea Mieg. comprises two narrowly distributed European taxa, Borderea pyrenaica (Bub.) Mieg. and B. chouardii (Gaussen) Heslot. An accumulation of facts such as that both species share a very close overall morphology, that only a single population of Borderea chouardii is known, and that they live in contrasting environments has led some authors to suggest that B. chouardii is a mere ecotype of the more widespread B. pyrenaica. We tested this hypothesis using RAPD markers in four populations of Borderea, three of them identified as B. pyrenaica and the other one representing the only known population of B. chouardii. Eleven out of twenty assayed pri…
Spatial analysis of lanner falcon habitat preferences: Implications for agro-ecosystems management at landscape scale and raptor conservation
2014
Abstract Sicily hosts the largest European population of the endangered lanner falcon, a poorly known species which needs conservation planning based on habitat preferences. A distribution model on 10 × 10 km cells of Sicily was described using Generalized Linear Models and variation partitioning methods. This modelling approach extracted explanatory factors, pure and joint effects of greatest influence from subsets of variables controlled for multi-collinearity and spatial autocorrelation. Analytical cartography used the environmental favourability function to assess habitat preferences, and the insecurity index estimated the degree to which lanner falcon occupancy is represented in the Na…
Genetic differentiation and structure of Hippocrepis valentina (Leguminosae) populations
2000
We present an analysis of isozyme variability in natural populations of the plant species Hippocrepis valentina (Leguminosae), which is endemic to the eastern Mediterranean coast of Spain and currently has endangered species status. Our results, obtained by starch-gel electrophoresis of 15 loci, show normal levels of variability for species with similar biology. The comparison with the patterns of genetic variability of two closely related species, H. balearica and H. grosii, confirms the taxonomic status of H. valentina as a proper species, independent of H. balearica, as previously suggested. The analysis of population subdivision shows that substantial variation among populations is pres…
Reproductive biology and conservation implications of three endangered snapdragon species (Antirrhinum, Plantaginaceae)
2009
About 32% of Antirrhinum species are considered to be endangered; however, no field studies have focused on their reproductive biology. In this work, several aspects of the reproductive biology (flowering phenology, floral biology, breeding system) and potential limits on seed quantity and quality (pollen limitation, inbreeding depression) were studied in natural populations of three endangered species of the genus (Antirrhinum charidemi, Antirrhinum subbaeticum, Antirrhinum valentinum). Results disclose that all three species need insect visitors for seed production since fruit set after autonomous self-pollination was lower than under hand cross-pollination. A. charidemi and A. valentinum…
Distribution, ecology and conservation status of Dionysia involucrata Zaprjag., an endangered endemic of Hissar Mts (Tajikistan, Middle Asia)
2014
<em>Dionysia involucrata</em> Zaprjag. (Primulaceae) is known as critically endangered endemic species of Hissar Mountains in Tajikistan. It is reported from few localities mainly in Varzob River valley and its tributaries. The species inhabits steep or overhanging faces of granite rocks in narrow river gorges. During the research all known populations of <em>D. involucrata</em> were examined in respect of the habitat conditions and species composition of vegetation plots. We analyzed the population extent of the species in its range in Tajikistan and the main threats in order to assess its conservation status. The detrended correspondence analysis was performed on a…
A newCentaureaspecies (Asteraceae) from Mt Sakar, South-eastern Bulgaria
2013
A new species of Centaurea, C. sakarensis, known from a single locality north-east of the village of Lessovo on Mt Sakar, is described and illustrated. It belongs to C. sect. Acrolophus, and its morphologically closest relative is C. cariensis Boiss., a Turkish endemic from western and south-western Anatolia. The new species is currently known from a single population of about 1000 individuals, growing on open stony calcareous places, at 475 m a.s.l., and should be classified as Critically Endangered, (B1ab[i, ii, iii]+2ab [i, ii, iii]).
Comparative analysis of biological and ecological differentiation of Anemone palmata L. (Ranunculaceae) in the western Mediterranean (France and Spai…
2002
The western Mediterranean geophyte Anemone palmata L. is one of the most endangered angiosperm taxa in France. The biological and ecological characteristics of French populations are contrasted with those of populations from near the centre of the species distribution in east Spain. A Correspondence Analysis discriminates the French and Spanish populations according to substrate and the composition of the plant communities where they grow. The karyological study reveals that east Spanish plants are autotetraploid, whilst the French are all diploid. In addition, morphological differences were registered, Spanish plants generally being more vigorous. French populations consist mostly of senil…
Habitat Preferences for Territory Selection by the Endangered Eastern Iberian Reed BuntingEmberiza Schoeniclus witherbyi
2014
Summary. Given the 80% decline of the eastern Iberian reed bunting Emberiza schoeniclus witherbyi breeding population in recent decades, our aim was to identify the habitat components selected during territory establishment and to characterise the vegetation features that are positively or negatively selected at the territory scale. GLMM were used to explain the occurrence of territories in 11 wetlands. Fourteen variables with four vegetation dominance categories were analysed with respect to habitat composition, while occupancy of seven vegetation classes and 12 reed structural parameters were analysed with respect to habitat structure. The proportion of reed-cattails (Typha) measured by t…