The causal and scaling relationships among anatomical traits explain tree mortality in subtropical forests under extremely high temperatures
Understanding species survival mechanisms under extreme high temperatures is crucial for comprehending how organisms respond to global climate change. However, the relationships between anatomical traits and tree mortality under extreme warming, as well as their underlying adaptation strategies in s...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-10-01
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| Series: | Global Ecology and Conservation |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2351989425003981 |
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| Summary: | Understanding species survival mechanisms under extreme high temperatures is crucial for comprehending how organisms respond to global climate change. However, the relationships between anatomical traits and tree mortality under extreme warming, as well as their underlying adaptation strategies in subtropical forest species, remain poorly understood. In this study, we established an altitudinal gradient as a temperature proxy at the regional scale and investigated tree crown mortality, anatomical-hydraulic traits, and transpiration characteristics of 74 woody species (32 deciduous and 42 evergreen species) in subtropical forests of Southwest China immediately following the extreme heat wave of 2022. Leaf anatomical, stomatal, and twig functional traits were measured to understand species responses to thermal stress. Our results revealed that: as air temperature increased with declining altitude, 1) deciduous and evergreen species exhibited fundamentally different adaptive pathways to thermal stress: deciduous species reduced crown mortality through increased midrib xylem area and enhanced twig transpiration, indicating a resource conservation strategy, whereas evergreen species experienced elevated mortality due to reduced midrib xylem investment, representing a resource abandonment strategy; 2) these contrasting survival strategies stem from distinct tissue allocation patterns—deciduous species maintain proportional increases in midrib phloem tissue relative to xylem expansion, while evergreens disproportionately reduce phloem allocation. Our findings demonstrate that forests may evolve novel ecological strategies to cope with extreme temperatures, and these strategies could serve as screening indicators for identifying climate-adaptive species. This research provides a scientific foundation for species selection and configuration at regional scales to enhance ecosystem resilience under future extreme heat scenarios. |
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| ISSN: | 2351-9894 |