Influence of fragmentation and climate on key processes for the regeneration of Holm oak forests

Abstract

Valladares, F., Flores-Rentería, D., Forner, A., Morán-López, Teresa, Díaz, M. 2014. Influence of fragmentation and climate on key processes for the regeneration of Holm oak forests. Ecosistemas 23(2): 37-47. Doi.: 10.7818/ECOS.2014.23-2.06

This paper reviews the main results of several lines of research on the effects of global change on Holm oak forests surrounded by an agricultural matrix and their regeneration capacity. We discuss our research on continuous and fragmented oak forests at two climatically contrasted locations. Our results suggest that fragmentation processes could mitigate some negative effects of climate change, namely the decreased productivity of Holm oak associated with an increased water stress. This attenuation would be verified by both the release of competition for water between trees near the edge and changes in microbial communities and functional properties of the soil. Because climate change operates directly on other processes such as phenology of trees and dispersants, it could lead to decoupling between the two groups of organisms and adversely affect their mutualism. The phenological decoupling between oaks and rodents observed in the more xeric populations might increase the vulnerability of oaks to global warming. Fragmentation had a negative effect on the quality of acorns dispersal due to the lack of safe places for dispersal agents and by decreasing intraspecific competition. It is conceivable that the combined effects of climate change and fragmentation threaten oak regeneration despite the counterintuitive positive effects of fragmentation on the physiology of oaks and on acorn production