Department of Botany and Plant Sciences, University of California, Riverside, California, 92501, USA.
School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, Arizona, 86001, USA.
Ecology. 2021 Apr;102(4):e03284. doi: 10.1002/ecy.3284. Epub 2021 Mar 15.
Climate and competition interact to affect species' performance, such as growth and survival, and help determine species distributions and coexistence. However, it is unclear how climatic conditions modulate frequency-dependent performance, that is, how performance changes as a species becomes locally rare or common. This is critical because declines in performance as a species becomes more common (negative frequency dependence) is a signature of niche differences among species that stabilize coexistence, whereas positive frequency dependence leads to priority effects and hampers species coexistence. Here, we used dendrochronology and hierarchical models to test whether frequency-dependent growth of sugar pine (Pinus lambertiana) depends on climatic conditions. We found that growth rates were strongly dependent on annual precipitation, but no frequency dependence was evident across all years. However, there was a strong interaction between precipitation and frequency dependence, revealing stabilizing niche differences in dry years but positive frequency dependence in wet years. These differences emerged because of precipitation-driven changes in the direction and strength of both con- and heterospecific competition. Overall, these results show how stabilizing and destabilizing effects can be temporally dynamic for long-lived species and interact with climate variation.
气候和竞争相互作用，影响物种的表现，如生长和存活，并有助于决定物种的分布和共存。然而，目前尚不清楚气候条件如何调节频率相关的性能，也就是说，随着一个物种在当地变得越来越稀有或常见，其性能会如何变化。这是至关重要的，因为随着一个物种变得越来越常见，其性能下降（负频率依赖）是物种之间生态位差异的特征，这些差异稳定了共存，而正频率依赖则会导致优先效应，并阻碍物种共存。在这里，我们使用树木年代学和层次模型来检验糖松（Pinus lambertiana）的频率依赖生长是否取决于气候条件。我们发现，生长速率强烈依赖于年降水量，但在所有年份都没有明显的频率依赖性。然而，降水和频率依赖性之间存在很强的相互作用，揭示了在干旱年份存在稳定的生态位差异，但在湿润年份存在正频率依赖性。这些差异的出现是由于降水驱动的同-和异-种竞争的方向和强度的变化。总的来说，这些结果表明，对于长寿命物种来说，稳定和不稳定的影响可能是随时间动态变化的，并与气候变化相互作用。
