Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Environment, Ecology, and Energy Program, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Glob Chang Biol. 2022 Feb;28(3):770-781. doi: 10.1111/gcb.15967. Epub 2021 Nov 8.
Anthropogenic change has altered the composition and function of ecological communities across the globe. As a result, there is a need for studies examining observed community compositional change and determining whether and how anthropogenic change drivers may be influencing that turnover. In particular, it is also important to determine to what extent community turnover is idiosyncratic or if turnover can be explained by predictable responses across species based on traits or niche characteristics. Here, we measured turnover in avian communities across North America from 1990 to 2016 in the Breeding Bird Survey using an ordination method, and modeled turnover as a function of land use and climate change drivers from local to regional scales. We also examined how turnover may be attributed to species groups, including foraging guilds, trophic groups, migratory distance, and breeding biomes. We found that at local scales, land use change explained a greater proportion of variance in turnover than climate change variables, while as scale increased, trends in temperature explained a greater proportion of variance in turnover. We also found across the study region, turnover could be attributed to one of a handful of species undergoing strong expansions or strong declines over the study time period. We did not observe consistent patterns in compositional change in any trait groups we examined except for those that included previously identified highly influential species. Our results have two important implications: First, the relative importance of different anthropogenic change drivers may vary with scale, which should be considered in studies' modeling impacts of global change on biodiversity. Second, in North American avian communities, individual species undergoing large shifts in population may drive signals in compositional change, and composite community turnover metrics should be carefully selected as a result.
人为因素的改变已经改变了全球生态群落的组成和功能。因此，需要研究观察到的群落组成变化，并确定人为变化驱动因素是否以及如何影响这种变化。特别是，确定群落变化在多大程度上是特殊的，或者变化是否可以根据物种的特征或生态位特征，通过可预测的反应来解释，这一点也很重要。在这里，我们使用排序方法，在 1990 年至 2016 年的繁殖鸟类调查中测量了北美的鸟类群落的周转率，并将周转率建模为当地到区域尺度的土地利用和气候变化驱动因素的函数。我们还研究了周转率可能归因于哪些物种组，包括觅食群体、营养级群体、迁徙距离和繁殖生物群系。我们发现，在当地尺度上，土地利用变化比气候变化变量解释了更多的周转率变化，而随着尺度的增加，温度趋势解释了更多的周转率变化。我们还发现，在整个研究区域，周转率可能归因于研究期间经历强烈扩张或强烈下降的少数几种物种之一。除了那些包括以前确定的高度有影响力的物种的特征组外，我们没有观察到任何特征组的组成变化中有一致的模式。我们的研究结果有两个重要的意义：第一，不同人为变化驱动因素的相对重要性可能因尺度而异，这在研究全球变化对生物多样性的影响时应加以考虑。第二，在北美的鸟类群落中，个体物种的种群可能会发生大的变化，从而驱动组成变化的信号，因此应该仔细选择综合群落周转率指标。
