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【6h】Forest loss and fragmentation in southern Bahia, Brazil: Implications for the extinction risk of golden-headed lion tamarins (Leontopithecus chrysomelas).

机译巴西巴伊亚州南部的森林流失和破碎化:对金头狮子ta猴(Leontopithecus chrysomelas)灭绝风险的影响。

【摘要】Golden-headed lion tamarins (GHLTs; Leontopithecus chrysomelas ) are Endangered arboreal primates endemic to the Atlantic Forest of Brazil, where continuing loss of forest and its connectivity are major threats. The objectives of my research were to assess the vulnerability of GHLTs to habitat loss, fragmentation, and threats related to small population size in the context of past, current, and future trends in range-wide forest cover in Brazil's Atlantic Forest. I did this by conducting a supervised classification of Landsat 5TM remotely-sensed imagery to define past and current forest cover in the region, analyzing connectivity patterns in a graph theoretical framework, projecting recent deforestation patterns into the future using a multi-layer perceptron neural network, and modeling GHLT metapopulaton viability using population viability analysis. I found that forest cover has declined throughout the range of the species by 13% over the last 20 years, and only one habitat patch is large enough on its own to support a genetically viable GHLT population able to recover from extrinsic threats such as fire and disease. Functional landscape connectivity, which is important for population persistence, acquisition of resources, and maintenance of genetic diversity, is low at the distance and movement cost thresholds likely associated with this arboreal species that is rarely seen in non-forest matrix. The majority of remaining forest cover throughout the species' range is found in patches that are either (1) too small to support even a single group of GHLTs or (2) found at low elevations, in areas of high human population density, or in close proximity to previously cleared areas--conditions that are associated with past deforestation patterns and that make current habitat vulnerable to loss. Finally, I found that many of the known GHLT populations have a moderate to high risk of local extinction even over short time scales and assuming no further forest loss, and their presence may represent extinction debt. Continued deforestation will accelerate population declines and local extinction events. The results of my dissertation research suggest that GHLTs and their habitat face significant threats and low viability in the future because of both ultimate and proximate drivers of extinction.

【摘要机译】金头狮子绢毛猴(GHLTs; Leontopithecus chrysomelas)是巴西大西洋森林特有的濒临灭绝的树栖灵长类动物,该国森林的持续丧失及其连通性是主要威胁。我研究的目的是在过去,现在和将来在巴西大西洋森林覆盖范围内的趋势的背景下,评估GHLT对栖息地丧失,破碎和与小规模人口相关的威胁的脆弱性。为此,我对Landsat 5TM遥感影像进行了监督分类,以定义该地区过去和当前的森林覆盖率,在图形理论框架中分析连通性模式,并使用多层感知器神经网络将最近的毁林模式投影到未来,并使用种群生存力分析对GHLT metapopulaton生存力进行建模。我发现在过去20年中,整个物种的森林覆盖率都下降了13%,而且只有一个栖息地斑块足够大,足以支持遗传上可行的GHLT种群,这些种群能够从火和疾病。功能性景观连通性对于人口的持久性,资源获取和遗传多样性的维持很重要,但在距离和移动成本的门槛很低的情况下,这种可能的连通性在非森林矩阵中很少见,与这种树栖物种有关。在整个物种范围内,大部分剩余的森林覆盖面积都位于以下区域:(1)面积太小,甚至无法支持一组GHLT;或者(2)在海拔低,人口密度高的地区或与先前砍伐的区域非常接近-与过去的森林砍伐模式相关的条件,使当前的栖息地容易遭受损失。最后,我发现,许多已知的GHLT种群即使在较短的时间范围内,也假设没有进一步的森林损失,都具有中度到高度的局部灭绝风险,而且它们的存在可能意味着灭绝债务。持续的森林砍伐将加速人口下降和局部灭绝事件。我的论文研究结果表明,由于灭绝的最终和近来的灭绝因素,GHLTs及其栖息地在未来面临着巨大的威胁和低生存力。

【作者】Zeigler, Sara L.;

【作者单位】University of Maryland, College Park.;

【年(卷),期】2010(),

【年度】2010

【页码】149 p.

【总页数】149

【原文格式】PDF

【正文语种】eng

【中图分类】;

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