Shifts in phenological mean and synchrony interact to shape competitive outcomes
Shifts in phenological mean and synchrony interact to shape competitive outcomes
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DOI：
10.1002/ecy.2826
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发表时间：
2019-08-14
期刊：
影响因子：
4.8
通讯作者：
Rudolf, Volker H. W.
中科院分区：
文献类型：
--
作者：
Carter, Shannon K.;Rudolf, Volker H. W.
气候变化引起的物候变化是普遍存在的，并有可能通过改变物种相互作用的时间来破坏自然群落。第一个和/或平均物候日期的变化是有据可查的，但最近的研究表明，同步性的变化（围绕这些指标的个体差异）可能同样常见。然而，我们知道很少这两种类型的物候变化如何相互作用，影响物种的相互作用和社区。在这里，我们实验操纵孵化物候的两个竞争物种的幼虫两栖动物，以解决这个概念的差距。具体来说，我们操纵的相对平均孵化时间（早期，相同，或相对于竞争对手晚）和人口同步（高，中，或低水平的平均值周围的变化）在一个完整的3 × 3析因设计，以衡量独立和相互作用的影响，物候平均值和人口物候同步竞争的结果。我们的研究结果表明，种群内的物候同步强烈影响种内竞争，通过改变密度的个人和相对强度的早与晚到达的个人。来自高同步性群体的个体对称地竞争，而来自低同步性群体的个体不对称地竞争。在社区尺度上，人口物候同步的变化与物候平均值的变化相互作用，强烈影响关键的人口统计率（生存，生物量出口，人均质量和出现时间）。此外，物种相互作用的平均时间的变化改变了下一个生命阶段的种群内的物候同步，在一个生命阶段的物候同步改变了下一个生命阶段的平均时间。因此，种群内物候同步的变化不仅可以改变物种间的相互作用，而且物种间的相互作用反过来也可以驱动物候的变化。
Climate change-induced phenological shifts are ubiquitous and have the potential to disrupt natural communities by changing the timing of species interactions. Shifts in first and/or mean phenological date are well documented, but recent studies indicate that shifts in synchrony (individual variation around these metrics) can be just as common. However, we know little about how both types of phenological shifts interact to affect species interactions and communities. Here, we experimentally manipulated the hatching phenologies of two competing species of larval amphibians to address this conceptual gap. Specifically, we manipulated the relative mean hatching time (early, same, or late relative to competitor) and population synchrony (high, medium, or low levels of variation around the mean) in a full 3 x 3 factorial design to measure independent and interactive effects of phenological mean and population phenological synchrony on competitive outcomes. Our results indicate that phenological synchrony within a population strongly influences intraspecific competition by changing the density of individuals and relative strength of early- vs. late-arriving individuals. Individuals from high-synchrony populations competed symmetrically, whereas individuals from low-synchrony populations competed asymmetrically. At the community scale, shifts in population phenological synchrony interact with shifts in phenological mean to affect key demographic rates (survival, biomass export, per capita mass, and emergence timing) strongly. Furthermore, changes in mean timing of species interactions altered phenological synchrony within a population at the next life stage, and phenological synchrony at one life stage altered the mean timing of the next life stage. Thus, shifts in phenological synchrony within populations cannot only alter species interactions, but species interactions in turn can also drive shifts in phenology.