Nowhere to hide: impact of a temperature-sensitive amphibian pathogen along an elevation gradient in the temperate zone
Nowhere to hide: impact of a temperature-sensitive amphibian pathogen along an elevation gradient in the temperate zone
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DOI：
10.1890/es11-00028.1
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发表时间：
2011-08-01
期刊：
影响因子：
2.7
通讯作者：
Maurer, Jeff R.
中科院分区：
文献类型：
--
作者：
Knapp, Roland A.;Briggs, Cheryl J.;Maurer, Jeff R.
两栖动物正在从世界各地的栖息地迅速消失，这些减少的主要原因是两栖动物壶菌（Batrachochytrium dendrobaerum）（“Bd”）。Bd的生长速率强烈依赖于温度，在温度远超出Bd具有高生长速率的包络线的区域，两栖动物可能会受到Bd影响的庇护。这种可能性在炎热的气候中得到了大量的经验支持，但在寒冷的气候中基本上没有得到检验。我们在约塞米蒂国家公园进行了一项为期五年的研究，研究Bd对海拔/温度梯度上下降的内华达州黄腿蛙（Rana sierleg）的影响。（2）详细描述了Bd感染强度、蛙种群数量和蛙种群持续性的季节变化规律;（3）青蛙易位实验，感染R.将来自单一源湖的细水雾沿海拔梯度沿着引入五个湖中的每一个。我们预测感染强度应该随着海拔的升高而降低（即，降低温度），因此青蛙的存活率，种群规模和种群持久性应随海拔升高而增加。调查结果表明，蛙种群数量随海拔升高而增加，但Bd感染强度和蛙种群持续性与海拔无关。季节性温度变化很大，但没有显着影响Bd感染强度。转座试验结果表明，Bd感染强度和转座后蛙的存活率与水温无关。因此，与广泛接受的范式相反，寒冷的环境应该强烈限制Bd对两栖动物的影响，我们发现即使在最高海拔也很少或根本没有这种限制的证据。因此，在温带山地生态系统中，高海拔不太可能为两栖动物提供Bd的避难所。
Amphibians are rapidly disappearing from habitats around the world and a major cause of these declines is the amphibian chytrid fungus, Batrachochytrium dendrobatidis ("Bd"). The growth rate of Bd is strongly temperature-dependent, and in areas where temperatures are well outside the envelope in which Bd has high growth rates, amphibians may be afforded a refuge from the effects of Bd. This possibility has received considerable empirical support in hot climates, but remains largely untested in cold climates. We conducted a five-year study of the impact of Bd on the declining Sierra Nevada yellow-legged frog (Rana sierrae) across an elevation/temperature gradient in Yosemite National Park using three approaches: (1) resurveys of all 285 R. sierrae populations to describe the landscape-scale patterns of Bd infection intensity, frog population size, and frog population persistence; (2) detailed description of seasonal patterns in temperatures and corresponding Bd infection intensities on R. sierrae; and (3) a frog translocation experiment in which infected R. sierrae from a single source lake were introduced into each of five lakes along an elevation gradient. We predicted that infection intensity should decrease with increasing elevation (i.e., decreasing temperature), and consequently frog survival, population size, and population persistence should increase with elevation. Results from resurveys indicated that frog population size increased with elevation but Bd infection intensity and frog population persistence were unrelated to elevation. Seasonal temperatures varied widely but had no significant effect on Bd infection intensity. Results from the translocation experiment indicated that Bd infection intensity and frog survival following translocation were also unrelated to water temperature. Therefore, contrary to the widely-accepted paradigm that cold environments should strongly limit effects of Bd on amphibians, we found little or no evidence of such limitation at even the highest elevations. Therefore, in temperate montane ecosystems it is unlikely that high elevations will provide amphibians with a refuge from Bd.