Stenseth Nils Chr, Durant Joël M, Fowler Mike S, Matthysen Erik, Adriaensen Frank, Jonzén Niclas, Chan Kung-Sik, Liu Hai, De Laet Jenny, Sheldon Ben C, Visser Marcel E, Dhondt André A
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066, Blindern, Oslo 0316, Norway
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066, Blindern, Oslo 0316, Norway.
Proc Biol Sci. 2015 May 22;282(1807):20141958. doi: 10.1098/rspb.2014.1958.
Climate change is expected to have profound ecological effects, yet shifts in competitive abilities among species are rarely studied in this context. Blue tits (Cyanistes caeruleus) and great tits (Parus major) compete for food and roosting sites, yet coexist across much of their range. Climate change might thus change the competitive relationships and coexistence between these two species. Analysing four of the highest-quality, long-term datasets available on these species across Europe, we extend the textbook example of coexistence between competing species to include the dynamic effects of long-term climate variation. Using threshold time-series statistical modelling, we demonstrate that long-term climate variation affects species demography through different influences on density-dependent and density-independent processes. The competitive interaction between blue tits and great tits has shifted in one of the studied sites, creating conditions that alter the relative equilibrium densities between the two species, potentially disrupting long-term coexistence. Our analyses show that long-term climate change can, but does not always, generate local differences in the equilibrium conditions of spatially structured species assemblages. We demonstrate how long-term data can be used to better understand whether (and how), for instance, climate change might change the relationships between coexisting species. However, the studied populations are rather robust against competitive exclusion.
气候变化预计会产生深远的生态影响，然而在这种背景下，物种间竞争能力的变化却很少被研究。蓝山雀（Cyanistes caeruleus）和大山雀（Parus major）会争夺食物和栖息位点，但在它们分布范围的大部分地区共存。因此，气候变化可能会改变这两个物种之间的竞争关系和共存状态。通过分析欧洲范围内关于这些物种的四个质量最高的长期数据集，我们将竞争物种共存的教科书式案例进行了扩展，以纳入长期气候变化的动态影响。使用阈值时间序列统计模型，我们证明长期气候变化通过对密度依赖和密度独立过程的不同影响来影响物种种群统计学。在其中一个研究地点，蓝山雀和大山雀之间的竞争相互作用已经发生了变化，创造出了改变这两个物种相对平衡密度的条件，有可能破坏长期共存状态。我们的分析表明，长期气候变化能够，但并非总是会，在空间结构物种组合的平衡条件上产生局部差异。我们展示了如何利用长期数据来更好地理解例如气候变化是否（以及如何）可能改变共存物种之间的关系。然而，所研究的种群对竞争排斥具有相当的抗性。
