School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Seattle, Washington, 98105, USA.
Fisheries Resource Assessment and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd East, Seattle, Washington, 98112, USA.
Ecology. 2017 Sep;98(9):2333-2342. doi: 10.1002/ecy.1944. Epub 2017 Aug 2.
Climate change is rapidly altering many aquatic systems, and life history traits and physiological diversity create differences in organism responses. In addition, habitat diversity may be expressed on small spatial scales, and it is therefore necessary to account for variation among both species and locations when evaluating climate impacts on biological communities. Here, we investigated the effects of temperature and spatial heterogeneity on long-term community composition in a large boreal lake. We used a five-decade time series of water temperature and relative abundance of fish species captured in the littoral zone throughout the summer at 10 discrete locations around the lake. We applied a spatial dynamic factor analysis (SDFA) model to this time series, which estimates the sensitivity of each species to changing water temperature while accounting for spatiotemporal variation. This analysis described the trend in community composition at each sampling location in the lake, given their different trends in temperature over time. The SDFA indicated different magnitude and direction of species responses to temperature; some species increased while others decreased in abundance. The model also identified five unique trends in species abundance across sites and time, indicating residual dynamics in abundance after accounting for temperature effects. Thus, different regions in the lake have experienced different trajectories in community change associated with different rates of temperature change. These results highlight the importance of considering habitat heterogeneity in explaining and predicting future species abundances, and our model provides a means of visualizing spatially-explicit temporal variation in species' dynamics.
气候变化正在迅速改变许多水生系统，而生活史特征和生理多样性则导致了生物对环境变化的响应存在差异。此外，栖息地多样性可能在小的空间尺度上表现出来，因此在评估气候对生物群落的影响时，有必要考虑物种和地点的变化。在这里，我们研究了温度和空间异质性对大型北方湖泊长期群落组成的影响。我们使用了 50 年来水温的时间序列和在夏季从湖岸 10 个离散位置捕获的鱼类物种的相对丰度，这些位置全年都有记录。我们将空间动态因子分析（SDFA）模型应用于该时间序列，该模型估计了每个物种对不断变化的水温的敏感性，同时考虑了时空变化。该分析描述了给定不同时间水温趋势的湖泊中每个采样点的群落组成趋势。SDFA 表明了物种对温度的响应的不同幅度和方向；一些物种的丰度增加，而另一些则减少。该模型还在不同地点和时间确定了五个独特的物种丰度趋势，这表明在考虑了温度影响后，丰度仍然存在动态变化。因此，不同地区的湖泊经历了与不同的温度变化速率相关的不同的群落变化轨迹。这些结果强调了考虑栖息地异质性在解释和预测未来物种丰度方面的重要性，我们的模型提供了一种可视化物种动态时空变化的方法。
