Opposing plant community responses to warming with and without herbivores
Opposing plant community responses to warming with and without herbivores
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DOI：
10.1073/pnas.0802421105
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发表时间：
2008-08-26
影响因子：
11.1
通讯作者：
Pedersen, Christian
中科院分区：
文献类型：
--
作者：
Post, Eric;Pedersen, Christian
如果对初级生产力和植物群落组成的控制主要是环境的，而不是生物的，那么全球变化可能会导致生态系统结构和功能的大规模变化。在对植物生物量和群落对实验和观测到的变暖反应的调查中，这一观点似乎更受欢迎。在遥远的北方和北极生态系统中，这类研究预测，随着未来变暖，木本灌木的优势将会增加，并强调这种反应的碳(C)固存潜力和随之而来的大气反馈潜力。与以前的研究不同，我们将麝牛和驯鹿的天然食草性纳入了一项为期5年的北极植物群落对气候变暖反应的实验调查。与其他研究一致，气候变暖通过促进落叶灌木(矮桦和灰柳)的生长来增加群落总生物量。然而，麝牛和驯鹿使群落总生物量以及桦树和柳树对气候变暖的响应分别降低了19%、46%和11%。此外，仅在变暖的情况下，植物群落在5年后从以禾本科植物为主转向以矮化桦树为主。相反，在草食动物放牧的地方，5年后，温暖地块的植物群落组成与周围地块的植物群落组成没有差别。这些结果突出了脊椎动物草食动物对植物群落对气候变暖反应的潜在重要和被忽视的影响，并强调对大型草食动物的保护和管理可能是减缓生态系统对气候变化反应的重要组成部分。
If controls over primary productivity and plant community composition are mainly environmental, as opposed to biological, then global change may result in large-scale alterations in ecosystem structure and function. This view appears to be favored among investigations of plant biomass and community responses to experimental and observed warming. in far northern and arctic ecosystems, such studies predict increasing dominance of woody shrubs with future warming and emphasize the carbon (C)-sequestration potential and consequent atmospheric feedback potential of such responses. In contrast to previous studies, we incorporated natural herbivory by muskoxen and caribou into a 5-year experimental investigation of arctic plant community response to warming. In accordance with other studies, warming increased total community biomass by promoting growth of deciduous shrubs (dwarf birch and gray willow). However, muskoxen and caribou reduced total community biomass response, and responses of birch and willow, to warming by 19%, 46%, and 11 %, respectively. Furthermore, under warming alone, the plant community shifted after 5 years away from graminoid-dominated toward dwarf birch-dominated. In contrast, where herbivores grazed, plant community composition on warmed plots did not differ from that on ambient plots after 5 years. These results highlight the potentially important and overlooked influences of vertebrate herbivores on plant community response to warming and emphasize that conservation and management of large herbivores may be an important component of mitigating ecosystem response to climate change.