Legacy effects of a regional drought on aboveground net primary production in six central US grasslands
Legacy effects of a regional drought on aboveground net primary production in six central US grasslands
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DOI：
10.1007/s11258-018-0813-7
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发表时间：
2018-05-01
期刊：
影响因子：
1.7
通讯作者：
Knapp, Alan K.
中科院分区：
文献类型：
--
作者：
Griffin-Nolan, Robert J.;Carroll, Charles J. W.;Knapp, Alan K.
全球气候模型预测，全球干旱的频率和严重程度都会增加，直接影响到大多数生态系统类型。因此，干旱遗留效应（干旱后生态系统功能的干旱引起的变化）预计将在从沙漠到草原到森林的各种生态系统中变得更加普遍。草原的干旱遗产通常是负面的，并降低生态系统功能，特别是在长期干旱之后。此外，对干旱反应强烈（高敏感性）的生态系统可能会在明年表现出最大的遗留影响，但这种关系尚未建立。我们量化了2012年严重区域性干旱对美国中部6个草原干旱后（2013年）地上净初级生产力（ANPP）的遗留影响。我们预测(1)2013年实测的干旱遗留效应的大小与2012年干旱的ANPP敏感性呈正相关，(2)干旱遗留效应为负相关（在正常降水条件下，2013年的ANPP相对于预期值降低）。2013年测量的遗留效应强度与ANPP对2012年干旱的敏感性呈强相关（r(2) = 0.88）。然而，与预期相反，积极的遗留效应（大于预期的ANPP）比消极遗留效应更常见。因此，虽然ANPP对干旱的敏感性可能是遗留影响程度的有用预测指标，但短期（1年）严重干旱可能造成的遗留影响比多年干旱后观察到的遗留影响更加多变。
Global climate models predict increases in the frequency and severity of drought worldwide, directly affecting most ecosystem types. Consequently, drought legacy effects (drought-induced alterations in ecosystem function postdrought) are expected to become more common in ecosystems varying from deserts to grasslands to forests. Drought legacies in grasslands are usually negative and reduce ecosystem function, particularly after extended drought. Moreover, ecosystems that respond strongly to drought (high sensitivity) might be expected to exhibit the largest legacy effects the next year, but this relationship has not been established. We quantified legacy effects of a severe regional drought in 2012 on postdrought (2013) aboveground net primary productivity (ANPP) in six central US grasslands. We predicted that (1) the magnitude of drought legacy effects measured in 2013 would be positively related to the sensitivity of ANPP to the 2012 drought, and (2) drought legacy effects would be negative (reducing 2013 ANPP relative to that expected given normal precipitation amounts). The magnitude of legacy effects measured in 2013 was strongly related (r (2) = 0.88) to the sensitivity of ANPP to the 2012 drought across these six grasslands. However, contrary to expectations, positive legacy effects (greater than expected ANPP) were more commonly observed than negative legacy effects. Thus, while the sensitivity of ANPP to drought may be a useful predictor of the magnitude of legacy effects, short-term (1-year) severe droughts may cause legacy effects that are more variable than those observed after multiyear droughts.