Department of Biology and IGDP in Ecology, The Pennsylvania State University, University Park, Pennsylvania, USA.
Ecol Appl. 2022 Sep;32(6):e2633. doi: 10.1002/eap.2633. Epub 2022 Jun 2.
Climate change alters many aspects of weed performance and may also alter the effectiveness of management practices to control pests. Despite this concern, entire categories of widely used management practices, such as physical control, remain understudied in this context. We conducted a field experiment growing the invasive pest musk thistle (Carduus nutans) at ambient and experimentally elevated temperatures. We tested mowing management strategies that varied in the timing of a single mowing event relative to thistles' stem elongation phenology and compared these with an unmowed control. Results from this experiment informed demographic models to project population growth rates for different warming/mowing scenarios. Compared to plants grown under ambient conditions, warmed thistles were more likely to survive the same mowing treatment, flowered earlier in the season, grew to taller heights, and produced more flowering capitula. Proportional reductions in plant height and capitulum production caused by mowing were smaller under warming. Warming did not change the relative ranking of mowing treatments; mowing late in the growing season (2 weeks after individuals first reached a height of 40 cm) was most effective at ambient temperatures and under warming. Warming caused significant increases in projected local population growth rate for all mowing treatments. For invasive musk thistle, warmed individuals outperformed individuals grown at ambient temperatures across all the mowing treatments we considered. Our results suggest that to achieve outcomes comparable to those attainable at today's temperatures, farmers will need to apply supplemental management, possibly including additional mowing effort or alternative practices such as chemical control. We recommend that scientists test management practices under experimental warming, where possible, and that managers monitor ongoing management to identify changes in effectiveness. Information about changes in managed weeds' mortality, fecundity, and phenology can then be used to make informed decisions in future climates.
气候变化改变了杂草表现的许多方面，也可能改变管理措施的有效性，以控制害虫。尽管存在这种担忧，但在这种情况下，物理控制等广泛使用的管理措施的整个类别仍未得到充分研究。我们在环境温度和实验升高的温度下进行了一项生长入侵性害虫豚草（Carduus nutans）的田间实验。我们测试了不同时间进行单次修剪的修剪管理策略，这些策略与未修剪的对照进行了比较。该实验的结果为人口增长模型提供了信息，以预测不同变暖/修剪情况下的种群增长率。与在环境条件下生长的植物相比，变暖的豚草更有可能在相同的修剪处理中存活下来，更早地开花，长得更高，并产生更多的开花头状花序。在变暖的情况下，修剪对植物高度和头状花序产量的比例减少较小。变暖并没有改变修剪处理的相对排名；在生长季节（个体首次达到 40 厘米高后 2 周）后期修剪在环境温度下和变暖条件下最有效。变暖导致所有修剪处理的预计局部种群增长率显著增加。对于入侵性的豚草，在所有我们考虑的修剪处理中，变暖的个体表现优于在环境温度下生长的个体。我们的结果表明，为了实现与今天的温度下可实现的结果相当的结果，农民将需要应用补充管理，可能包括额外的修剪工作或替代实践，如化学控制。我们建议科学家在实验变暖的情况下测试管理措施，并建议管理者监测正在进行的管理，以识别有效性的变化。关于管理杂草死亡率、繁殖力和物候变化的信息可以用于在未来气候下做出明智的决策。
