Deforestation, host community structure, and amphibian disease risk
Deforestation, host community structure, and amphibian disease risk
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DOI：
10.1016/j.baae.2015.08.004
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发表时间：
2016-02-01
影响因子：
3.8
通讯作者：
Zamudio, Kelly R.
中科院分区：
文献类型：
--
作者：
Guilherme Becker, C.;Rodriguez, David;Zamudio, Kelly R.
栖息地的干扰和壶菌的出现(Bd)与两栖动物的加速衰退有关。森林砍伐可以通过非生物和生物机制，包括当地小气候的变化和物种的相互作用，直接改变两栖动物的群落结构。反过来，两栖动物群落属性的变化可能会影响Bd的传播动态，从而对生物多样性的持久性也有间接的作用。在这里，我们测试了森林砍伐是否通过改变两栖动物群落结构，包括物种丰富度、群落组成、总宿主密度和宿主生物量来影响Bd感染。我们在美国和巴西调查了22个温带和热带两栖动物群落，跨越森林砍伐的梯度，我们实验地将每个两栖动物群落的一个有代表性的亚样本暴露在受控小气候下的中附体中标准化的Bd游动孢子负载中。我们发现，当小气候保持不变时，通常在原始地点发现的密度较高的温带两栖动物群落显示出更高的Bd负荷。相比之下，在原始森林中发现的热带两栖动物群落在没有可变小气候的情况下携带较低的Bd感染负荷，这可能是由于它们的宿主物种组成。之前在热带社区中宿主对病原体的暴露也在确定感染负荷方面发挥了重要作用；我们发现在野外和实验室观察到的Bd感染负荷之间存在负相关。我们的结果强调，砍伐森林可以对疾病风险产生级联生物效应，量化宿主社区属性对Bd感染的净贡献将有助于我们确定疾病的具体驱动因素，并为保护战略提供参考。
Habitat disturbances and the emergence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) are linked to accelerated amphibian declines. Deforestation can directly alter amphibian community structure through abiotic and biotic mechanisms including shifts in local microclimates and species interactions. Changes in amphibian community attributes, in turn, potentially impact Bd transmission dynamics, and thus also have an indirect role in biodiversity persistence. Here, we tested whether deforestation influences Bd infections through shifts in amphibian community structure, including species richness, community composition, total host density, and host biomass. We surveyed 22 temperate and tropical amphibian communities across gradients of deforestation in the U.S. and Brazil, and we experimentally exposed a representative subsample of each amphibian community to standardized Bd zoospore loads in mesocosms under controlled microclimate. We found that denser temperate amphibian communities commonly found at pristine sites showed higher Bd loads when microclimates were held constant. In contrast, tropical amphibian communities found at pristine forest sites carried lower Bd infection loads in the absence of variable microclimates, likely due to their host species composition. Previous host exposure to the pathogen in tropical communities also played an important role in determining infection loads; we identified a negative association between Bd infection loads observed in the wild and in the laboratory. Our results highlight that deforestation can have cascading biotic effects on disease risk, and that quantifying the net contribution of host community attributes to Bd infections will help us identify specific drivers of disease and inform conservation strategies.