Resource redistribution mediated by hydrological connectivity modulates vegetation response to aridification in drylands

IF 5.4 1区环境科学与生态学 Q1 BIODIVERSITY CONSERVATION

Ecography Pub Date : 2025-01-21 DOI:10.1111/ecog.07650

Borja Rodríguez-Lozano, Emilio Rodríguez-Caballero, and Yolanda Cantón

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引用次数: 0

Abstract

Water scarcity poses a significant life constraint in global drylands that determines species adaptations and mosaic of exposed bare areas and vegetation patches. Runoff-water redistribution resulting from this spatial configuration has been suggested as a key process controlling water availability for vegetation and ecosystem functioning. However, the potential of this process to ameliorate the negative impacts of aridification in drylands remains unclear, and there is no empirical evidence of its relevance on natural ecosystems under different levels of aridity and disturbance regimes. To address this gap, we analysed temporal series of the normalized vegetation index (NDVI, a proxy of vegetation functioning) along a regional aridity–disturbance gradient under current and future climatic conditions. We found that mean NDVI increases in areas of runoff water accumulation (calculated using a water redistribution index) until a certain threshold, above which vegetation patches are not able to retain extra runoff water. Once thresholds were identified, we analysed the role of water redistribution on vegetation dynamics by analysing temporal series of monthly NDVI in a space–for–time substitution approach. The obtained results provided further evidence of the runoff water redistribution on vegetation, triggering a positive feedback between water accumulation and vegetation growth. Results obtained by the combination of the obtained model with climatic data from the 6th IPCC report suggest that this feedback could ameliorate the expected negative effects of aridification in drylands. However, this effect is partially counterbalanced in scenarios of high human disturbance and in areas where vegetation is not able to trap and retain the extra amount of resources given by runoff. Overall, our results provide empirical evidence of the relevance of runoff redistribution as a key process linking vegetation patterns to climate resistance in drylands that underscores its importance in the analysis and modelling of drylands' responses to aridification.

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水文连通性介导的资源再分配调节旱地植被对干旱化的响应

水资源短缺对全球旱地的生命构成了重大制约，它决定了物种的适应以及裸露区域和植被斑块的镶嵌。这种空间配置导致的径流-水再分配被认为是控制植被和生态系统功能水分有效性的关键过程。然而，这一过程在改善旱地干旱化负面影响方面的潜力仍不清楚，并且没有经验证据表明它与不同程度的干旱和干扰制度下的自然生态系统的相关性。为了解决这一差距，我们分析了当前和未来气候条件下，标准化植被指数（NDVI，植被功能的代表）沿区域干旱扰动梯度的时间序列。我们发现，径流水积累区（使用水再分配指数计算）的平均NDVI增加，直到某个阈值，超过该阈值，植被斑块无法保留额外的径流水。一旦确定了阈值，我们通过分析月NDVI的时间序列，采用时空替代方法分析了水分再分配对植被动态的作用。研究结果进一步证明了径流水分对植被的再分配，引发了水分积累与植被生长之间的正反馈关系。将所获得的模型与IPCC第6次报告中的气候数据相结合得到的结果表明，这种反馈可以改善旱地干旱化的预期负面影响。然而，在高度人为干扰的情况下，以及在植被无法捕获和保留径流提供的额外资源的地区，这种影响被部分抵消。总体而言，我们的研究结果提供了径流再分配相关性的经验证据，表明径流再分配是旱地植被模式与气候抗性联系起来的关键过程，强调了径流再分配在旱地干旱化响应分析和建模中的重要性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ecography 环境科学-生态学

CiteScore

11.60

自引率

3.40%

发文量

122

审稿时长

8-16 weeks

期刊介绍： ECOGRAPHY publishes exciting, novel, and important articles that significantly advance understanding of ecological or biodiversity patterns in space or time. Papers focusing on conservation or restoration are welcomed, provided they are anchored in ecological theory and convey a general message that goes beyond a single case study. We encourage papers that seek advancing the field through the development and testing of theory or methodology, or by proposing new tools for analysis or interpretation of ecological phenomena. Manuscripts are expected to address general principles in ecology, though they may do so using a specific model system if they adequately frame the problem relative to a generalized ecological question or problem. Purely descriptive papers are considered only if breaking new ground and/or describing patterns seldom explored. Studies focused on a single species or single location are generally discouraged unless they make a significant contribution to advancing general theory or understanding of biodiversity patterns and processes. Manuscripts merely confirming or marginally extending results of previous work are unlikely to be considered in Ecography. Papers are judged by virtue of their originality, appeal to general interest, and their contribution to new developments in studies of spatial and temporal ecological patterns. There are no biases with regard to taxon, biome, or biogeographical area.