Functional trait responses of bromeliad invertebrate communities to altered precipitation along a biogeographic gradient

CARRIAS, J.F.; CÉRÉGHINO R.; FARJALLA V.; CORBARA B.; MACDONALD, A.; HAMMILL E.; GUSTAVO PICCOLI; MONTERO G.A.; TRZCINSKI M.K.; REALPE E.; SRIVASTAVA D.; BARBERIS I.M.; DÉZERALD O.; LEROY C.; OSPINA BAUTISTA F.; ROMERO G.

Montpellier

Congreso; 53rd Annual Meeting of the Association for Tropical Biology and Conservation; 2016

Association for Tropical Biology and Conservation

Background. Anthropogenic climate change is predicted to increase the frequency and intensity of extreme climatic events such assevere droughts. Yet, we don?t know how biological communities will respond to altered precipitation regimes, nor whether responsesobserved at any given site can be extrapolated to other sites when communities show biogeographic turnover in functional traits thatdetermine how organisms interact with their environment.Method. We manipulated the amount and frequency of rainfall entering tank bromeliad ecosystems at six field sites ranging from18°N in the Caribbean to 29°S in South-America. We examined generalities in the response of the functional trait diversity ofbromeliad invertebrates to precipitation change, by asking whether (1) precipitation change (notably drought) consistently increasethe prevalence of certain functional traits at the expense of other traits, and (2) changes in precipitation patterns have differentselective effects than changes in bromeliad hydrology.Results. Overall, bromeliad hydrology had greater effects on the distribution of abundance-weighted traits within communities thanprecipitation per se. Drought mostly selected traits that confer in situ resistance to dessication, but also ability to move actively tomore suitable microsites under stressful conditions. Traits counter-selected were clearly site-specific, certainly because species poolsat the different sites differed in their abundance-weighted trait compositions. However, the magnitude of hydrological effects on traitdiversity depended both on baseline, site-specific precipitation regimes, and on how bromeliad size and architectural complexitybuffered changes in precipitation.Conclusion. The composition of the species pool and the buffering capacity of physical habitats determine the extent of communitylevel,functional responses to altered precipitation regimes in neotropical countries. Theoretical models seeking to link functional traitsto environmental conditions in an attempt to predict ecosystem responses to climate change should certainly include turnovers inbiological and environmental settings.