Moss Wynne E, McDevitt-Galles Travis, Muths Erin, Bobzien Steven, Purificato Jessica, Johnson Pieter T J
University of Colorado, Department of Ecology & Evolutionary Biology, Boulder, CO.
Conservation Science Partners, Inc. Fort Collins, CO.
Biol Conserv. 2021 Nov;263. doi: 10.1016/j.biocon.2021.109352. Epub 2021 Oct 2.
The increasing frequency and severity of drought may exacerbate ongoing global amphibian declines. However, interactions between drought and coincident stressors, coupled with high interannual variability in amphibian abundances, can mask the extent and underlying mechanisms of drought impacts. We synthesized a decade (2009 - 2019) of regional-scale amphibian monitoring data (2273 surveys, 233 ponds, and seven species) from across California's Bay Area and used dynamic occupancy modeling to estimate trends and drivers of species occupancy. An extreme drought during the study period resulted in substantial habitat loss, with 51% of ponds drying in the worst year of drought, compared to <20% in pre-drought years. Nearly every species exhibited reduced breeding activity during the drought, with the occupancy of some species (American bullfrogs and California newts) declining by >25%. Invasive fishes and bullfrogs were also associated with reduced amphibian occupancy, and these taxa were locally extirpated from numerous sites during drought, without subsequent recovery-suggesting that drought may present an opportunity to remove invaders. Despite a historic, multi-year drought, native amphibians rebounded quickly to pre-drought occupancy levels, demonstrating evidence of resilience. Permanent waterbodies supported higher persistence of native species during drought years than did temporary waterbodies, and we therefore highlight the value of hydroperiod diversity in promoting amphibian stability.
干旱发生频率和严重程度的不断增加，可能会加剧全球两栖动物持续减少的趋势。然而，干旱与同时存在的应激源之间的相互作用，再加上两栖动物数量的年际变化较大，可能会掩盖干旱影响的程度和潜在机制。我们综合了加利福尼亚湾区十年（2009 - 2019年）的区域尺度两栖动物监测数据（2273次调查、233个池塘和7个物种），并使用动态占有率模型来估计物种占有率的趋势和驱动因素。研究期间的一场极端干旱导致了大量栖息地丧失，在干旱最严重的年份，51%的池塘干涸，而干旱前的年份这一比例不到20%。几乎每个物种在干旱期间的繁殖活动都有所减少，一些物种（美国牛蛙和加州蝾螈）的占有率下降了25%以上。入侵鱼类和牛蛙也与两栖动物占有率的降低有关，在干旱期间，这些类群在许多地点被局部灭绝，且没有随后的恢复——这表明干旱可能为清除入侵者提供了机会。尽管经历了一场历史性的多年干旱，本地两栖动物迅速反弹至干旱前的占有率水平，显示出恢复力的证据。在干旱年份，永久性水体比临时性水体更能支持本地物种的持续存在，因此我们强调水文周期多样性在促进两栖动物稳定性方面的价值。
