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RAIMON GUITART RAQUEL CLAVERO RAFAEL MATEO MANUEL MÁÑEZ 《Journal of environmental science and health. Part. B》2013,48(5):753-760
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) residue levels were determined in 53 unhatched eggs from greater roseus flamingos (Phoenicopterus ruber). Eggs were collected in 1996 from the National Park of Doñana (Guadalquivir marshes, Southwest Spain), immediately after one breeding colony abandoned the nesting site due to predator attacks. The main metabolite of p,p′-DDT, p,p′-DDE, was the OCP residue found at higher concentrations, with a geometric mean of 721 ng/g wet weight. Residues of other pesticides, including some hexachlorocyclohexane isomers, hexachlorobenzene, aldrin, heptachlor, and heptachlor-epoxide, were detected at much lower concentrations. The sum of PCBs was 528 ng/g, with PCB congeners #187 and #153 being the most prominent in eggs. The pattern observed in these compounds of industrial origin corresponded more to Aroclor 1260 than to any other commercial mixture. Levels of organochlorine residues indicate a medium degree of exposure, and they are not considered of any concern for the flamingo population. In particular, neither p,p′-DDE nor PCB levels were found to be correlated with the eggshell thickness. 相似文献
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MIGUEL DELIBES‐MATEOS MIGUEL DELIBES PABLO FERRERAS RAFAEL VILLAFUERTE 《Conservation biology》2008,22(5):1106-1117
Abstract: The Mediterranean Basin is a global hotspot of biodiversity. Hotspots are said to be experiencing a major loss of habitat, but an added risk could be the decline of some species having a special role in ecological relationships of the system. We reviewed the role of European rabbits (Oryctolagus cuniculus) as a keystone species in the Iberian Peninsula portion of the Mediterranean hotspot. Rabbits conspicuously alter plant species composition and vegetation structure through grazing and seed dispersal, which creates open areas and preserves plant species diversity. Moreover, rabbit latrines have a demonstrable effect on soil fertility and plant growth and provide new feeding resources for many invertebrate species. Rabbit burrows provide nest sites and shelter for vertebrates and invertebrates. In addition, rabbits serve as prey for a number of predators, including the critically endangered Iberian lynx (Lynx pardinus) and Spanish Imperial Eagle (Aquila adalberti). Thus, the Mediterranean ecosystem of the Iberian Peninsula should be termed “the rabbit's ecosystem.” To our knowledge, this is the first empirical support for existence of a multifunctional keystone species in a global hotspot of biodiversity. Rabbit populations have declined drastically on the Iberian Peninsula, with potential cascading effects and serious ecological and economic consequences. From this perspective, rabbit recovery is one of the biggest challenges for conservation of the Mediterranean Basin hotspot. 相似文献
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VIRGINIA GALLEGOS PÉRULA RAFAEL M. NAVARRO CERRILLO PILAR FERNÁNDEZ REBOLLOo GEMADEL VALLE MURILLO 《Environmental management》2003,31(1):0086-0099
The objective of this study was to examine postfire regeneration of tree, shrub, and dwarf shrub species, in relation to levels
of damage in four planted pine forests (Pinus pinea, Pinus pinaster) in Andalusia. A prefire vegetation map was used for detailing species composition, vertical structure, and density and another
for detailing the extent and intensity of fire damage. Between 3 and 7 years after the fires, an inventory was made of the
vegetation in each area, using the step-point method. The information thus obtained was used to determine the amount of cover
in the dwarf/shrub and tree layers, the frequency of species in each of the layers, floristic richness, and diversity (Shannon
index). The botanical composition of the dwarf and shrub layer was analyzed using TWINSPAN. Variables were poorly correlated
with level of fire damage, which suggests that the forests in this study followed the autosuccession model. Because of the
artificial origin or seminatural condition, regeneration of the dominant tree species is poor, and it seems unlikely that
forests will recover to their prefire state. Therefore action is recommended to restore these ecosystems. 相似文献
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Abstract: Amazonia is a highly threatened rainforest that encompasses a major proportion of Earth's biological diversity. Our main goal was to establish conservation priorities for Amazonia's areas of endemism on the basis of measures of evolutionary distinctiveness. We considered two previously identified sets of areas of endemism. The first set consisted of eight large areas used traditionally in biogeographical studies: Belém, Tapajós, Xingu, Guiana, Rondônia, Imeri, Inambari, and Napo. The second set consisted of 16 smaller areas that were subdivisions of the larger areas. We assembled a data set of 50 phylogenies that represented 16 orders and 1715 distributional records. We identified priority conservation areas for the areas of endemism according to node‐based metrics of evolutionary distinctiveness. We contrasted these results with priority areas identified on the basis of raw species richness and species endemicity. For the larger areas, we identified Guiana and Inambari as the first‐ and second‐most important areas for conservation. The remaining areas in this first group scored half (e.g., Napo) or less than Guiana and Inambari on all indices. For the smaller areas, a subdivision of Guiana (i.e., Guyana and the Brazilian states of Roraima and Amazonas) was at the top of the ranking and was followed by a subdivision of Inambari (i.e., northwestern portion of Amazonas) and then another subdivision of Guiana (i.e., Suriname, French Guiana, and the Brazilian state of Amapá). The distinctiveness‐based rankings of the priority of areas correlated directly with those derived from species richness and species endemicity. Current conservation strategies in Amazonia, although they rely on many other criteria apart from phylogeny, are focusing on the most important areas for conservation we identified here. 相似文献
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RAFAEL BARRIENTOS JUAN CARLOS ALONSO CARLOS PONCE CARLOS PALACÍN 《Conservation biology》2011,25(5):893-903
Abstract: Collisions of birds with power transmission and distribution lines have been documented for many species, and cause millions of casualties worldwide. Attempts to reduce mortality from such collisions include placing bird flight diverters (i.e., wire markers in the form of, e.g., spirals, swivels, plates, or spheres) on static and some electrified wires to increase their visibility. Although studies of the effectiveness of such devices have yielded contradictory results, the implementation of flight diverters is increasing rapidly. We reviewed the results of studies in which transmission or distribution wires were marked and conducted a meta‐analysis to examine the effectiveness of flight diverters in reducing bird mortality. We included in our meta‐analysis all studies in which researchers searched for carcasses of birds killed by a collision with wires. In those studies that also included data on flight frequency, we examined 8 covariates of effectiveness: source of data, study design, alternate design (if marked and unmarked spans were alternated in the same line), periodicity of searches for carcasses, width of the search transect, and number of species, lines, and stretches of wire searched. The presence of flight diverters was associated with a decrease in bird collisions. At unmarked lines, there were 0.21 deaths/1000 birds (n =339,830) that flew among lines or over lines. At marked lines, the mortality rate was 78% lower (n =1,060,746). Only the number of species studied had a significant influence on effect size; this was larger in studies that addressed more species. When comparing mortality at marked and unmarked lines, we recommend use of the same time intervals and habitats and standardizing the periodicity of carcass searches. 相似文献
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