Effects of Niche Marginality on Hotter-Drought Tree Mortality in Angiosperms and Gymnosperms

IF 6 1区环境科学与生态学 Q1 ECOLOGY

Global Ecology and Biogeography Pub Date : 2025-09-21 DOI:10.1111/geb.70128

Enric Batllori, William M. Hammond, Alistair Jump, María Ángeles Pérez-Navarro, Craig D. Allen, Francisco Lloret

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引用次数: 0

Abstract

Aim

Current observations of global tree mortality events associated with drought raise concerns about climate change risks to forests' dynamics and function. It is unclear which forests are more susceptible to pulses of mortality under further changing climates. We examined whether tree mortality related to hotter droughts is predominantly occurring in edge or core populations in niche space and assessed whether mortality patterns are consistent with species' drought tolerances.

Location: Global.

Time Period: 1970–2020.

Major Taxa Studied: Angiosperm and gymnosperm trees.

Methods

We estimated species' climatic niches on the basis of global occurrences and annual time series of climate. We computed the distance to the niche core of drought mortality sites (982 observations, 44 tree species) and compared it with null models of randomly distributed tree mortality. We assessed how loss of xylem conductance and hydraulic safety margin related to populations' position in niche space and to the degree of climate anomaly during mortality.

Results

In the year of mortality, 64.3% of the sites were closer to the species' niche edge than the niche core. However, when considering long-term climate averages, both marginal and central populations experienced drought-associated pulses of mortality. Overall, tree mortality was related to populations' shifts towards the edge of species' climatic niches and, in angiosperm mortality sites, species' drought tolerances were correlated with the intensity of climatic anomalies. In gymnosperm sites, marginal populations were more affected and other processes, such as heat-induced stress or cumulative drought effects, may have affected mortality.

Main Conclusions

Both marginal and central populations, even for highly drought-tolerant species, are vulnerable to climate change. Climate anomaly magnitude, cumulative drought effects, plant physiological limits and species niche geometry help explain range-wide patterns of hotter-drought-associated tree mortality.

Abstract Image

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生态位边缘性对被子植物和裸子植物热旱树木死亡率的影响

目前对与干旱相关的全球树木死亡事件的观测引起了人们对气候变化对森林动态和功能的风险的关注。目前尚不清楚在气候进一步变化的情况下，哪些森林更容易受到死亡率波动的影响。我们研究了与高温干旱相关的树木死亡是否主要发生在生态位空间的边缘或核心种群中，并评估了死亡模式是否与物种的耐旱性一致。地点:全球。时间范围：1970-2020年。研究的主要分类群：被子植物和裸子植物树。方法根据全球气候变化和年气候时间序列估算物种的气候生态位。我们计算了干旱死亡地点到生态位核心的距离（982个观测点，44个树种），并将其与随机分布树木死亡率的零模型进行了比较。我们评估了木质部导度和水力安全边际的损失与种群在生态位空间中的位置和死亡期间气候异常程度的关系。结果在死亡年，64.3%的生境更靠近物种生态位边缘，而不是生态位核心。然而，在考虑长期气候平均值时，边缘和中心人口都经历了与干旱相关的死亡率波动。总体而言，树木死亡率与种群向物种气候生态位边缘的转移有关，在被子植物死亡地点，物种的耐旱性与气候异常的强度相关。在裸子植物区，边缘种群受到的影响更大，其他过程，如热胁迫或累积干旱效应，可能影响了死亡率。主要结论：无论是边缘种群还是中心种群，即使是高度耐旱的物种，也容易受到气候变化的影响。气候异常幅度、累积干旱效应、植物生理极限和物种生态位几何有助于解释与高温干旱相关的树木死亡的大范围模式。

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来源期刊

Global Ecology and Biogeography 环境科学-生态学

CiteScore

12.10

自引率

3.10%

发文量

170

审稿时长

3 months

期刊介绍： Global Ecology and Biogeography (GEB) welcomes papers that investigate broad-scale (in space, time and/or taxonomy), general patterns in the organization of ecological systems and assemblages, and the processes that underlie them. In particular, GEB welcomes studies that use macroecological methods, comparative analyses, meta-analyses, reviews, spatial analyses and modelling to arrive at general, conceptual conclusions. Studies in GEB need not be global in spatial extent, but the conclusions and implications of the study must be relevant to ecologists and biogeographers globally, rather than being limited to local areas, or specific taxa. Similarly, GEB is not limited to spatial studies; we are equally interested in the general patterns of nature through time, among taxa (e.g., body sizes, dispersal abilities), through the course of evolution, etc. Further, GEB welcomes papers that investigate general impacts of human activities on ecological systems in accordance with the above criteria.