Olivier Dézerald

PhD defended on November, 12th 2015

Climate change and food webs: impact on biodiversity and ecosystem functioning**

The extent to which climate change will affect ecosystem functioning through changes in species distribution remains debated, because it is difficult to extrapolate individual species responses to complex networks of species interactions, and because the size/heterogeneity of large ecosystems hampers our ability to distinguish clear patterns. The simple faunal food web inhabiting water-filled bromeliads (aquatic insects and miscellaneous invertebrates) forms a suitable model to address the issue of network stability in relation to environmental changes using manipulative experiments, because it is small in size, highly replicated, and occurs throughout the neotropics. We will experimentally increase or decrease precipitation entering bromeliads to study effects on the bromeliad-dwelling species, food webs, and ecosystem processes. Specifically, we aim (1) to determine the responses of invertebrate populations, food webs (composition, functional groups), and ecosystem processes (carbon and nitrogen dynamics, decomposition, carbon dioxide and methane emission) to a range of scenarios of precipitation alterations; (2) to determine whether these responses are driven by changes in species composition or differences in habitat conditions; (3) to disentangle the direct effects of precipitation change mediated by organism physiology from the indirect effects mediated by interactions between species. We concentrate on precipitation because it is understudied (compared to temperature) and has potentially profound impact for ecosystems, and specifically on Neotropical ecosystems, which are expected to lose more species than their temperate counterparts. We will pay particular attention to mosquito larvae that develop in tank-bromeliads, in an attempt to shed new light on the population responses of vectors of arboviruses to predicted climate changes.

FSE Guyane {PNG}Union Européenne {PNG}

Student funded by the European Union and labex Ceba.

Labex Ceba {PNG}

Publications for EcoFoG

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