Enhancement of ecosystem carbon uptake in a dry shrubland under moderate warming: The role of nitrogen‐driven changes in plant morphology. (16th August 2021)

• Record Type: Journal Article
• Authors: Liberati, Dario; Guidolotti, Gabriele; de Dato, Giovanbattista; De Angelis, Paolo
• Is Part Of: Global change biology. Volume 27:Number 21(2021)
• Page Start: 5629
• Page End: 5642
• Publication Date: 2021-08-16
• Subjects: canopy photosynthesis -- Cistus monspeliensis -- dry shrubland -- experimental warming -- net ecosystem exchange -- nutrient limitations -- shoot size -- temperature limitations to plant growth; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15823
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Net ecosystem CO2 exchange is the result of net carbon uptake by plant photosynthesis and carbon loss by soil and plant respiration. Temperature increases due to climate change can modify the equilibrium between these fluxes and trigger ecosystem‐climate feedbacks that can accelerate climate warming. As these dynamics have not been well studied in dry shrublands, we subjected a Mediterranean shrubland to a 10‐year night‐time temperature manipulation experiment that analyzed ecosystem carbon fluxes associated with dominant shrub species, together with several plant parameters related to leaf photosynthesis, leaf morphology, and canopy structure. Under moderate night‐time warming (+0.9°C minimum daily temperature, no significant reduction in soil moisture), Cistus monspeliensis formed shoots with more leaves that were relatively larger and denser canopies that supported higher plant‐level photosynthesis rates. Given that ecosystem respiration was not affected, this change in canopy morphology led to a significant enhancement in net ecosystem exchange (+47% at midday). The observed changes in shoot and canopy morphology were attributed to the improved nutritional state of the warmed plants, primarily due to changes in nitrogen cycling and higher nitrogen resorption efficiency in senescent leaves. Our results show that modifications in plant morphology triggered by moderate warming affected ecosystem CO2 fluxes, providing the first evidence for enhanced daytime carbon uptake in a dry shrubland ecosystem under experimental warming. Abstract : Temperature increases due to climate change can modify the equilibrium between net carbon uptake by plant photosynthesis and carbon loss by soil and plant respiration. We subjected a dry shrubland to a 10‐year night‐time temperature manipulation experiment (+0.9°C minimum air temperature) that analyzed ecosystem carbon fluxes associated with dominant shrub species Cistus monspeliensis . Our results show that modifications in plant morphology triggered by moderate warming enhanced plant photosynthesis, with no significant effect on ecosystem respiration, providing the first evidence for improved ecosystem carbon uptake in a dry shrubland under experimental warming.