Habitat fragmentation reduces genetic diversity and connectivity among toad populations in the Brazilian Atlantic Coastal Forest
Habitat fragmentation reduces genetic diversity and connectivity among toad populations in the Brazilian Atlantic Coastal Forest
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DOI：
10.1016/j.biocon.2008.11.016
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发表时间：
2009-08-01
影响因子：
5.9
通讯作者：
Zamudio, Kelly R.
中科院分区：
文献类型：
--
作者：
Dixo, Marianna;Metzger, Jean Paul;Zamudio, Kelly R.
热带雨林正变得越来越支离破碎，了解支离破碎的遗传后果对于保护热带雨林的动植物至关重要。我们研究了巴西大西洋海岸森林特有的一种鹦鹉Rhinella ornata的种群，并比较了被隔离或通过走廊与大型林区相连的中小型森林片段的遗传多样性。F-ST法测量的遗传分化与研究地点之间的地理距离无关，片段的大小也没有显著改变遗传连通性的模式。然而，群体遗传多样性与片段大小呈正相关，因此最小片段的单倍型多样性最低，这可能是由于群体大小的减少所致。对种群间遗传不连续性的空间分析表明，在连续森林中，中小片段之间的基因流动障碍比例高于种群之间的障碍。我们的结果强调，即使是具有相对较高扩散能力的物种，随着时间的推移，也可能遭受碎片化的负面遗传影响，可能导致种群适合度降低和局部灭绝的情况。(C)2008爱思唯尔有限公司。保留所有权利。
Tropical rainforests are becoming increasingly fragmented and understanding the genetic consequences of fragmentation is crucial for conservation of their flora and fauna. We examined populations of the toad Rhinella ornata, a species endemic to Atlantic Coastal Forest in Brazil, and compared genetic diversity among small and medium forest fragments that were either isolated or connected to large forest areas by corridors. Genetic differentiation, as measured by F-ST, was not related to geographic distance among study sites and the size of the fragments did not significantly alter patterns of genetic connectivity. However, population genetic diversity was positively related to fragment size, thus haplotype diversity was lowest in the smallest fragments, likely due to decreases in population sizes. Spatial analyses of genetic discontinuities among groups of populations showed a higher proportion of barriers to gene flow among small and medium fragments than between populations in continuous forest. Our results underscore that even species with relatively high dispersal capacities may, over time, suffer the negative genetic effects of fragmentation, possibly leading to reduced fitness of population and cases of localized extinction. (C) 2008 Elsevier Ltd. All rights reserved.