The combined effects of an extreme heatwave and wildfire on tallgrass prairie vegetation
The combined effects of an extreme heatwave and wildfire on tallgrass prairie vegetation
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极端热浪和野火对高草草原植被的综合影响
DOI：
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发表时间：
2019
影响因子：
2.8
通讯作者：
S. Collins
中科院分区：
文献类型：
--
作者：
Z. Ratajczak;A. Churchill;Laura M. Ladwig;Jeffrey H. Taylor;S. Collins
问题：据预测，极端气候在许多生态系统中将变得更加普遍。极端气候现象可以促进干扰并与干扰相互作用，但在许多生态系统中，极端气候现象和干扰的综合影响尚未量化。在这项研究中，我们问的是，气候极端和伴随的干扰（野火）的双重影响是否比单独的气候极端有更大的影响。地点：美国堪萨斯东北部康扎草原生物站的高草草原。方法：我们量化了一个高草草原植物群落对2年极端气候的反应，即低生长季降水和高温。在极端气候的第一年，一部分地块被生长季节的野火烧毁。这个自然实验使我们能够比较社区对有野火和没有野火的极端气候的反应。研究结果：在暴露于极端气候但不暴露于野火的地块中，群落结构、多样性和组成显示出微小到不显著的变化，例如草地覆盖减少20%，物种多样性略有增加。暴露于极端气候和野火的地块经历了更大的变化，包括草地覆盖减少80%，杂类草覆盖增加50%，植物多样性增加。在极端气候发生两年后，烧毁地块的结构变化几乎没有恢复的迹象，这表明植物群落结构可能会发生持久的变化。结论：我们的研究结果表明，社区对极端气候的反应需要考虑与气候相关的干扰-在这种情况下，高温，干旱和野火。这种反应与我们的预期不同，我们认为炎热，干旱和额外的火灾将有利于草。虽然近几十年来高草草原的生长季节野火很少发生，但随着气候变化，它们可能会变得更加常见，可能导致草原结构的变化。
QUESTIONS: Climate extremes are predicted to become more common in many ecosystems. Climate extremes can promote and interact with disturbances, but the combined effects of climate extremes and disturbances have not been quantified in many ecosystems. In this study, we ask whether the dual impact of a climate extreme and concomitant disturbance (wildfire) has a greater affect than a climate extreme alone. LOCATION: Tallgrass prairie in the Konza Prairie Biological Station, northeastern Kansas, USA. METHODS: We quantified the response of a tallgrass prairie plant community to a 2‐year climate extreme of low growing‐season precipitation and high temperatures. In the first year of the climate extreme, a subset of plots was burned by a growing‐season wildfire. This natural experiment allowed us to compare community responses to a climate extreme with and without wildfire. RESULTS: In plots exposed to the climate extreme but not wildfire, community structure, diversity, and composition showed minor to insignificant changes, such as a 20% reduction in grass cover and a slight increase in species diversity. Plots exposed to both the climate extreme and wildfire underwent larger changes, including an 80% reduction in grass cover, 50% increase in forb cover, and increased plant diversity. Two years after the climate extreme, structural shifts in burned plots showed little sign of recovery, indicating a potentially lasting shift in plant community structure. CONCLUSIONS: Our results suggest that community responses to climate extremes need to account for climate‐related disturbances — in this case, high temperatures, drought and wildfire. This response diverged from our expectation that heat, drought, and an additional fire would favor grasses. Although growing‐season wildfires in tallgrass prairie have been rare in recent decades, they will likely become more common with climate change, potentially leading to changes in grassland structure.
DOI：
10.1073/pnas.0505734102
发表时间：
2005-10-18
影响因子：
11.1
作者：
Breshears, DD;Cobb, NS;Meyer, CW
通讯作者：
Meyer, CW