Influence of climate variations on primary production indicators and on the resilience of forest ecosystems in a future scenario of climate change: Application to sweet chestnut agroforestry systems in the Iberian Peninsula

Abstract

Sweet chestnut agroforestry systems make valuable contributions to the landscape and environment, fulfilling fundamental functions and processes. Net primary production (NPP) and carbon use efficiency (CUE) are commonly used as ecological indicators to evaluate the responses of the terrestrial carbon cycle to climate change. Nonetheless, although climate-induced primary production changes have been widely documented at the global scale, few studies have addressed this issue at local scale in relation to sweet chestnut forests. Data from 65 climate maps and MODIS remote-sensed data captured in the Iberian Peninsula between 2000 and 2015 were analysed in this study. Different statistical methods (Linear Regression and Classification and Regression Trees) were used to analyse the potential influence of climate change on sweet chestnut primary production, thus enabling assessment of ecosystem and ecosystem service (ES) supply and of the resilience of these systems in a future scenario of climate change in the Iberian Peninsula. The findings for the whole of the Iberian Peninsula show that NPP and CUE are negatively correlated with temperature variables and positively correlated with latitude. High NPP values mainly corresponded to northern Spain, which is characterised by cold, humid conditions. The CUE values were highest in northern Portugal, mainly in managed, monospecific forest. Overall, the fitted models showed a temporary response in which the monthly variables were particularly important and water availability was more important than temperature. The findings suggest that precipitation is not a limiting factor in Atlantic areas, but that water availability tends to be a limiting factor in Mediterranean areas. However, mean annual temperature (MAT) is also an important driver of sweet chestnut production and may be a limiting factor in a future scenario of climate change. Regions of Provenance (RoP) proved useful for explaining NPP and CUE and classifying the sweet chestnut agroforestry systems. Finally, the study findings also revealed that Iberian sweet chestnut ecosystems and the associated ES supplies are at risk of being seriously affected or even disappearing as a result of climate change, especially in some Mediterranean areas of southern and central Spain.