Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA, USA.
Glob Chang Biol. 2013 Sep;19(9):2688-97. doi: 10.1111/gcb.12228. Epub 2013 Jul 15.
Few studies have quantitatively projected changes in demography in response to climate change, yet doing so can provide important insights into the processes that may lead to population declines and changes in species distributions. Using a long-term mark-recapture data set, we examined the influence of multiple direct and indirect effects of weather on adult and juvenile survival for a population of Song Sparrows (Melospiza melodia) in California. We found evidence for a positive, direct effect of winter temperature on adult survival, and a positive, indirect effect of prior rainy season precipitation on juvenile survival, which was consistent with an effect of precipitation on food availability during the breeding season. We used these relationships, and climate projections of significantly warmer and slightly drier winter weather by the year 2100, to project a significant increase in mean adult survival (12-17%) and a slight decrease in mean juvenile survival (4-6%) under the B1 and A2 climate change scenarios. Together with results from previous studies on seasonal fecundity and postfledging survival in this population, we integrated these results in a population model and projected increases in the population growth rate under both climate change scenarios. Our results underscore the importance of considering multiple, direct, and indirect effects of weather throughout the annual cycle, as well as differences in the responses of each life stage to climate change. Projecting demographic responses to climate change can identify not only how populations will be affected by climate change but also indicate the demographic process(es) and specific mechanisms that may be responsible. This information can, in turn, inform climate change adaptation plans, help prioritize future research, and identify where limited conservation resources will be most effectively and efficiently spent.
很少有研究定量预测气候变化对人口结构的影响，但这样做可以深入了解可能导致人口减少和物种分布变化的过程。本研究使用长期的标记-重捕数据集，考察了天气对加利福尼亚州歌雀（Melospiza melodia）成体和幼体存活率的直接和间接影响。结果表明，冬季温度对成体存活率有正向的直接影响，前一个雨季降水对幼体存活率有正向的间接影响，这与降水对繁殖季节食物供应的影响一致。我们利用这些关系以及到 2100 年冬季显著变暖、略微干燥的气候预测数据，预测在 B1 和 A2 气候变化情景下，平均成体存活率（12-17%）显著增加，平均幼体存活率（4-6%）略有下降。结合本研究中对该种群季节性繁殖力和离巢后存活率的先前研究结果，我们将这些结果整合到一个种群模型中，并预测在两种气候变化情景下种群增长率的增加。研究结果强调了在整个年周期内考虑天气的多种直接和间接影响以及每个生命阶段对气候变化响应的差异的重要性。预测气候变化对人口结构的影响不仅可以确定气候变化将如何影响种群，还可以指示可能负责的人口过程和特定机制。这些信息反过来可以为气候变化适应计划提供信息，帮助确定未来研究的优先事项，并确定有限的保护资源将在哪里最有效和高效地使用。
