Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon, 97403, USA.
Plant Biology Department, University of Georgia, Athens, Georgia, 30606, USA.
Ecology. 2021 Oct;102(10):e03464. doi: 10.1002/ecy.3464. Epub 2021 Aug 5.
With ongoing climate change, populations are expected to exhibit shifts in demographic performance that will alter where a species can persist. This presents unique challenges for managing plant populations and may require ongoing interventions, including in situ management or introduction into new locations. However, few studies have examined how climate change may affect plant demographic performance for a suite of species, or how effective management actions could be in mitigating climate change effects. Over the course of two experiments spanning 6 yr and four sites across a latitudinal gradient in the Pacific Northwest, United States, we manipulated temperature, precipitation, and disturbance intensity, and quantified effects on the demography of eight native annual prairie species. Each year we planted seeds and monitored germination, survival, and reproduction. We found that disturbance strongly influenced demographic performance and that seven of the eight species had increasingly poor performance with warmer conditions. Across species and sites, we observed 11% recruitment (the proportion of seeds planted that survived to reproduction) following high disturbance, but just 3.9% and 2.3% under intermediate and low disturbance, respectively. Moreover, mean seed production following high disturbance was often more than tenfold greater than under intermediate and low disturbance. Importantly, most species exhibited precipitous declines in their population growth rates (λ) under warmer-than-ambient experimental conditions and may require more frequent disturbance intervention to sustain populations. Aristida oligantha, a C4 grass, was the only species to have λ increase with warmer conditions. These results suggest that rising temperatures may cause many native annual plant species to decline, highlighting the urgency for adaptive management practices that facilitate their restoration or introduction to newly suitable locations. Frequent and intense disturbances are critical to reduce competitors and promote native annuals' persistence, but even such efforts may prove futile under future climate regimes.
随着气候变化的持续，预计人口的人口表现将发生变化，这将改变一个物种能够生存的地方。这给植物种群管理带来了独特的挑战，可能需要持续的干预措施，包括就地管理或引入新的地点。然而，很少有研究探讨气候变化如何影响一系列物种的植物人口表现，也很少有研究探讨有效的管理措施如何缓解气候变化的影响。在横跨美国太平洋西北地区的 6 年和 4 个地点的两个实验中，我们操纵了温度、降水和干扰强度，并量化了它们对 8 种本地一年生草原物种的人口统计学的影响。每年我们都会种植种子并监测发芽、存活和繁殖。我们发现干扰强烈影响人口表现，而在温暖条件下，其中 7 种物种的表现越来越差。在不同的物种和地点，我们观察到在高干扰下有 11%的幼苗（种植的种子存活到繁殖的比例），而在中等干扰和低干扰下分别只有 3.9%和 2.3%。此外，在高干扰下，种子的平均产量往往比中等干扰和低干扰下高出十倍以上。重要的是，大多数物种在温暖的实验条件下表现出种群增长率（λ）的急剧下降，可能需要更频繁的干扰干预来维持种群。Aristida oligantha，一种 C4 草，是唯一一种随着温度升高而λ增加的物种。这些结果表明，气温升高可能导致许多本地一年生植物物种减少，这凸显了适应性管理实践的紧迫性，以促进它们的恢复或引入新的适宜地点。频繁和强烈的干扰对于减少竞争者和促进本地一年生植物的生存至关重要，但即使在未来的气候条件下，这些努力也可能是徒劳的。
