Abstract:
Ecologists are being challenged to predict how ecosystems will respond to climate changes. According to the Multi-Colored World (MCW) hypothesis, climate impacts may not manifest because consumers such as fire and herbivory can override the influence of climate on ecosystem state. One MCW interpretation is that climate determinism fails because alternative ecosystem states (AES) are possible at some locations in climate space. We evaluated theoretical and empirical evidence for the proposition that forest and savanna are AES in Africa. We found that maps which infer where AES zones are located were contradictory. Moreover, data from longitudinal and experimental studies provide inconclusive evidence for AES. That is, although the forest-savanna AES proposition is theoretically sound, the existing evidence is not yet convincing. We conclude by making the case that the AES proposition has such fundamental consequences for designing management actions to mitigate and adapt to climate change in the savanna-forest domain that it needs a more robust evidence base before it is used to prescribe management actions.
摘要:
生态学家面临着预测生态系统将如何应对气候变化的挑战。根据多色世界(MCW)假设,气候影响可能不会显现出来,因为火和食草动物等消费者可以超越气候对生态系统状态的影响。MCW的一种解释是气候决定论失败,因为在气候空间的某些位置可能存在替代生态系统状态(AES)。我们评估了森林和稀树草原在非洲是AES这一命题的理论和经验证据。我们发现推断AES区域所在位置的地图是矛盾的。此外,纵向和实验研究的数据为AES提供了不确定的证据。也就是说,尽管森林稀树草原AES命题在理论上是合理的,现有的证据还不能令人信服。我们得出的结论是,AES命题对于设计管理行动以减轻和适应稀树草原森林领域的气候变化具有如此根本的后果,因此在用于规定管理行动之前,需要更强大的证据基础。