Skaer Thomason Meghan J, Rice Kevin J
Department of Plant Sciences, University of California, Davis, Davis, California, United States of America.
PLoS One. 2017 Jan 3;12(1):e0169328. doi: 10.1371/journal.pone.0169328. eCollection 2017.
It is important to predict which invasive species will benefit from future changes in climate, and thereby identify those invaders that need particular attention and prioritization of management efforts. Because establishment, persistence, and spread determine invasion success, this prediction requires detailed demographic information. Explicit study of the impact of pattern on demographic response is particularly important for species that are naturally patchy, such as the invasive grass, Aegilops triuncialis. In the northern California Coast Range, where climate change may increase or decrease mean annual rainfall, we conducted a field experiment to understand the interaction of climate change and local-scale patterning on the demography of A. triuncialis. We manipulated precipitation (reduced, ambient, or augmented), seed density, and seeding pattern. Demographic and environmental data were collected for three years following initial seeding. Pattern and scale figure prominently in the demographic response of A. triuncialis to precipitation manipulation. Pattern interacts with precipitation and seeding density in its influence on per-plant seed output. Although per-plot seed production was highest when seeds were not aggregated, per-plant seed output was higher in aggregated patches. Results suggest aggregation of invasive A. triuncialis reduces the detrimental impact of interspecific competition in its invaded community, and that interspecific competition per se has a stronger impact than intraspecific competition.
预测哪些入侵物种将从未来的气候变化中获益，从而确定那些需要特别关注并优先进行管理的入侵物种，这一点很重要。由于定殖、存续和扩散决定了入侵的成功与否，这种预测需要详细的种群统计学信息。对于像入侵性杂草——节节麦这样自然分布呈斑块状的物种而言，明确研究格局对种群统计学响应的影响尤为重要。在加利福尼亚州北部海岸山脉，气候变化可能会增加或减少年平均降水量，我们在此开展了一项田间实验，以了解气候变化与局部尺度格局对节节麦种群统计学特征的相互作用。我们对降水量（减少、环境水平或增加）、种子密度和播种格局进行了控制。在初次播种后的三年里收集了种群统计学和环境数据。格局和尺度在节节麦对降水控制的种群统计学响应中显著体现。格局在影响单株种子产量时，与降水量和播种密度相互作用。虽然当种子不聚集时每小区的种子产量最高，但在聚集斑块中单株种子产量更高。结果表明，入侵的节节麦聚集分布可降低其在入侵群落中种间竞争的不利影响，并且种间竞争本身的影响比种内竞争更强。
