"Disentangling the interactive effects of exotic pathogens and climate change on Mediterranean forests"

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Summary

Global change is a complex phenomenon involving several factors that act simultaneously. However, most of their combined effects on natural ecosystems remain poorly understood. In this talk I will synthesize recent work conducted in mixed oak forests of southern Spain that aims to explore the interactive effects of two main threats to their long-term sustainability: exotic pathogens and climate change.  I will first highlight the understudy role of exotic pathogens as determinants of demographic rates in Mediterranean tree species, and their importance as drivers of plant-soil feedbacks that could reinforce the loss of dominance of tree species affected by pathogen-driven decline. Then, I will discuss experimental evidence from the field and the greenhouse that supports the existence of non-additive, antagonistic effects of exotic pathogens and increasing drought on tree demography. Such results imply that Mediterranean forests could be less susceptible to the combined effects of these two stressors than to their individual effects when considered separately. This pattern of interaction among global change drivers strongly differs from the synergistic effects commonly reported in the literature. Overall, this talk represents an invitation to think and discuss about the complexity of predicting forest responses to multiple global change drivers, particularly under the idiosyncrasy of Mediterranean environments.

Biography 

Lorena Gómez-Aparicio is a researcher at the Spanish National Research Council (CSIC). She received her PhD from the University of Granada (Spain) in 2004, and was a Fulbright Postdoctoral Fellow at the Cary Institute of Ecosystem Studies (NY, USA). Since 2010 she works at the Institute of Natural Resources and Agrobiology of Seville (Spain), where she leads the research group on Mediterranean Forest Systems. She is a forest ecologist interested in understanding the dynamics of forest systems as a fundamental requirement for their sustainable management. Her research combines tools and approaches from different research areas (ecophysiology, plant demography, community ecology, soil microbiology, biogeochemistry) at different spatial scales, from description of large-scale patterns of forest demography to detailed mechanistic studies in the field and greenhouse. Among the different mechanisms driving forest dynamics, she is particularly interested in species interactions among plants, animals and microbes, and how these interactions can vary in sign and magnitude conditioning species coexistence and ecosystem function A large part of the ongoing research in her lab is motivated by the increasing problem of changing tree demographic rates (higher mortality, lower growth and regeneration) in forests worldwide, and in Mediterranean oak forests in particular.