Thermal heterogeneity mediates the effects of pulsed subsidies across a landscape
Thermal heterogeneity mediates the effects of pulsed subsidies across a landscape
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DOI：
10.1890/09-0790.1
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发表时间：
2010-05-01
期刊：
影响因子：
4.8
通讯作者：
Quinn, Thomas P.
中科院分区：
文献类型：
--
作者：
Armstrong, Jonathan B.;Schindler, Daniel E.;Quinn, Thomas P.
空间和时间的异质性相互作用，使个体的觅食率比假设栖息地条件的空间和时间维度独立运作的模型预期的更具变化性。例如，营养资源脉冲产生的猎物过剩的时间补丁，但很少有人知道如何在栖息地条件的空间异质性介导的消费者利用这些高品质的觅食机会的能力。我们研究了水温的空间变化如何调节青少年银鲑利用溯河产卵的红鲑产生的鸡蛋的季节性脉冲补贴的潜力。美国阿拉斯加州西南部伍德河流域的溪流夏季平均温度为3.6摄氏度至14.5摄氏度。青少年coho季节性鸡蛋补贴的到来之前的增长呈正相关，流之间的水温。结合现场饮食样本的原位实验揭示了鸡蛋消费的大小阈值;由于较小个体的张口限制，只有长于70 mm的个体才能消费鸡蛋。生物能量学模拟表明，水温调节年龄0银鲑是否可以成长到足够大，超过鸡蛋消费的大小阈值。食用鸡蛋的银鲑的能量配给是不食用鸡蛋的鱼的五倍，导致水温对其综合季节性生长的正反馈。在整个景观中，水温的异质性介导了个体和种群对季节性可用资源脉冲的响应。我们的研究表明，与仅基于生理学的预测相比，生态机制，如基于大小的觅食不对称性，可以放大气候变化的影响。
Spatial and temporal heterogeneity interact to make the foraging rates of individuals more variable than expected from models assuming that spatial and temporal dimensions of habitat conditions operate independently. For example, trophic resource pulses produce temporal patches of prey superabundance, yet little is known about how spatial heterogeneity in habitat conditions mediates the ability of consumers to exploit these high-quality foraging opportunities. We studied how spatial variation in water temperature regulates the potential for juvenile coho salmon to exploit a seasonal pulsed subsidy of eggs produced by anadromous sockeye salmon. Streams within the Wood River watershed, southwestern Alaska, USA, ranged in mean summer temperature from 3.6 degrees to 14.5 degrees C. Growth of juvenile coho prior to the arrival of the seasonal egg subsidy was positively related to water temperature among streams. An in situ experiment combined with field samples of diets revealed a size threshold for egg consumption; only individuals longer than similar to 70 mm could consume eggs due to gape limitation of smaller individuals. A bioenergetics simulation demonstrated that water temperature regulated whether age-0 coho salmon could grow large enough to exceed the size threshold for egg consumption. Coho salmon that consumed eggs had energy rations that were five times higher than fish that did not consume eggs, resulting in a positive feedback of water temperature on their integrated seasonal growth. Across this landscape, heterogeneity in water temperature mediates individual- and population-level responses to seasonally available resource pulses. Our study illustrates that ecological mechanisms, such as size-based foraging asymmetries, can magnify the effects of climate change compared to predictions based on physiology alone.