Africa’s ecosystems exhibit a tradeoff between resistance and stability following disturbances
Africa’s ecosystems exhibit a tradeoff between resistance and stability following disturbances
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DOI：
10.1088/1748-9326/acde90
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发表时间：
2023-06
影响因子：
6.7
通讯作者：
D. Lauer;Jenny L. McGuire
中科院分区：
文献类型：
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作者：
D. Lauer;Jenny L. McGuire
环境干扰可能使生态系统无法持续发挥其重要的生态功能。生态系统的两个重要特性是其抵抗力和稳定性，这分别反映了其承受干扰事件（如干旱、野火、虫害等）和从干扰事件中恢复的能力。理论表明，抗性和稳定的生态系统具有相反的特征，但这很少在不同的生态系统属性或广泛的空间尺度上建立。在这里，我们比较了2000年至2019年非洲超过1000个保护区生态系统对干扰引起的初级生产力损失的抵抗力和稳定性。我们定量地评估了每个生态系统，以便在干扰之后，如果生态系统的生产力损失较小，则其抵抗力更强，如果其更快地恢复到干扰前的生产力水平，则其更稳定。为了比较抗性生态系统与稳定生态系统的特征，我们优化了随机森林模型，这些模型使用生态系统属性（代表其气候和环境条件，植物和动物的生物多样性以及对人类影响的暴露）来预测其抗性和稳定性值。在考虑模型框架中的所有其他属性后，我们可视化了每个属性与阻力和稳定性的关系。生态系统对干扰的抵抗力越强，稳定性就越差，反之亦然。在我们的模型中，具有最大预测能力的生态系统属性都表现出阻力与稳定性的对比关系。值得注意的是，高抵抗力的生态系统通常更干旱，表现出高度的生境异质性和哺乳动物生物多样性，而高度稳定的生态系统则相反。我们讨论的基本机制，通过这些属性产生的阻力，或相反，稳定。我们的研究结果表明，阻力和稳定性是根本对立的现象。如果生态系统要在面对环境变化时保持其特性、结构和功能，就必须在两者之间取得平衡。
Environmental disturbances may prevent ecosystems from consistently performing their critical ecological functions. Two important properties of ecosystems are their resistance and stability, which respectively reflect their capacities to withstand and recover from disturbance events (e.g. droughts, wildfires, pests, etc). Theory suggests that resistant and stable ecosystems possess opposing characteristics, but this has seldom been established across diverse ecosystem attributes or broad spatial scales. Here, we compare the resistance and stability of >1000 protected area ecosystems in Africa to disturbance-induced losses in primary productivity from 2000 to 2019. We quantitatively evaluated each ecosystem such that following disturbances, an ecosystem is more resistant if it experiences lower-magnitude losses in productivity, and more stable if it returns more rapidly to pre-disturbance productivity levels. To compare the characteristics of resistant versus stable ecosystems, we optimized random forest models that use ecosystem attributes (representing their climatic and environmental conditions, plant and faunal biodiversity, and exposure to human impacts) to predict their resistance and, separately, stability values. We visualized each attribute’s relationship with resistance and stability after accounting for all other attributes in the model framework. Ecosystems that are more resistant to disturbances are less stable, and vice versa. The ecosystem attributes with the most predictive power in our models all exhibit contrasting relationships with resistance versus stability. Notably, highly resistant ecosystems are generally more arid and exhibit high habitat heterogeneity and mammalian biodiversity, while highly stable ecosystems are the opposite. We discuss the underlying mechanisms through which these attributes engender resistance or, conversely, stability. Our findings suggest that resistance and stability are fundamentally opposing phenomena. A balance between the two must be struck if ecosystems are to maintain their identity, structure, and function in the face of environmental change.