Resistance and resilience of a grassland ecosystem to climate extremes
Resistance and resilience of a grassland ecosystem to climate extremes
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DOI：
10.1890/13-2186.1
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发表时间：
2014-09-01
期刊：
影响因子：
4.8
通讯作者：
Smith, Melinda D.
中科院分区：
文献类型：
--
作者：
Hoover, David L.;Knapp, Alan K.;Smith, Melinda D.
气候变化预测表明，气候极端事件将更加频繁，这类事件将成为未来生态系统动态和功能的越来越重要的驱动因素。由于自然发生的极端气候的罕见性和不可预测性限制了对其生态影响的评估，我们在美国中部的一个地区进行了为期两年的极端干旱和仲夏热浪的实验。S.草原虽然生态系统对热浪有抵抗力，但对极端干旱却没有抵抗力，这导致地上净初级生产力（ANPP）低于该草原近30年来测量的最低水平。生态系统功能的这种极端减少是C-4草和C-3杂类草生产力降低的结果。然而，占主导地位的杂类草受到干旱的负面影响比占主导地位的草，这导致了植物群落内的物种丰度的重新排序。虽然这种变化在社会组成持续干旱后，ANPP完全恢复干旱后的一年，由于人口的快速反应，占主导地位的草，补偿损失的优势杂类草。总的来说，这些结果表明，极端气候（例如，例如，在一个实施例中，抗性低）并不妨碍生态系统的快速恢复。鉴于少数物种占主导地位是大多数生态系统的特点，了解这些物种的特点及其对极端气候的反应将是预测未来生态系统动态和功能的关键。
Climate change forecasts of more frequent climate extremes suggest that such events will become increasingly important drivers of future ecosystem dynamics and function. Because the rarity and unpredictability of naturally occurring climate extremes limits assessment of their ecological impacts, we experimentally imposed extreme drought and a midsummer heat wave over two years in a central U. S. grassland. While the ecosystem was resistant to heat waves, it was not resistant to extreme drought, which reduced aboveground net primary productivity (ANPP) below the lowest level measured in this grassland in almost 30 years. This extreme reduction in ecosystem function was a consequence of reduced productivity of both C-4 grasses and C-3 forbs. However, the dominant forb was negatively impacted by the drought more than the dominant grass, and this led to a reordering of species abundances within the plant community. Although this change in community composition persisted post-drought, ANPP recovered completely the year after drought due to rapid demographic responses by the dominant grass, compensating for loss of the dominant forb. Overall, these results show that an extreme reduction in ecosystem function attributable to climate extremes (e. g., low resistance) does not preclude rapid ecosystem recovery. Given that dominance by a few species is characteristic of most ecosystems, knowledge of the traits of these species and their responses to climate extremes will be key for predicting future ecosystem dynamics and function.