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Carbon Gain, Carbon Use, and Persistence: How Elevated CO₂ and Warming Reshape High‐Elevation Plants

Year: 2026
Type: article
Abstract: ABSTRACT High‐elevation plants operate within a tightly constrained carbon economy shaped by low temperature, short growing seasons, shallow soils, and reduced atmospheric CO 2 partial pressure. Elevated CO 2 and climate warming are widely expected to enhance carbon uptake in these systems, yet persistent biomass gains and long‐term carbon sequestration remain inconsistent. Here, we synthesise experimental, observational, and modelling evidence to propose a three‐gate framework: carbon gain (Gate 1), carbon use (Gate 2), and persistence (Gate 3) to explain alpine plant responses to global change. Elevated CO 2 frequently increases leaf‐level photosynthesis and intrinsic water‐use efficiency, while moderate warming can transiently stimulate early‐season productivity. However, sink limitation, nutrient imbalance, elevated respiration, and rhizosphere priming constrain structural carbon deployment. Excess assimilates are often diverted to non‐structural carbohydrate storage, antioxidant systems, and secondary metabolism rather than durable biomass accumulation. Critically, demographic filters, phenological mismatch, recruitment failure, and stage‐specific mortality govern long‐term persistence. We argue that persistence, not productivity, ultimately determines alpine carbon stability. Incorporating allocation constraints and demographic processes into ecosystem models is essential for improving projections of mountain carbon–climate feedbacks.
Language: English
Subfield: Plant Science
Open Access status: green
OpenAlex ID: W7154696340
FWCI: 7.353
Cites: 91
Cited by: 2
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