Trophic cascades, diversity and ecosystem functioning

Our group investigates the magnitude of top-down effects of predators cascading down to lower trophic levels (prey density and diversity, plant fitness) within aquatic and terrestrial ecosystems, and across ecosystems. We develop manipulative experiments in the field using aquatic microecosystems (tank bromeliads, artificial microcosms), mesocosms and terrestrial food webs (plant-pollinator-herbivore-predator interactions). We are interested in how predator identity and diversity affect magnitude of trophic cascade and ecosystem functioning, and if these effects occur through trait- or density-mediated interactions. The effects of predator and prey diversity (functional, phylogenetic and alpha diversity) on ecosystem functioning are also investigated.     

 

 

Food web structure and dynamics

We are interested in how trophic pyramids are structured according to latitude, and through productivity and other environmental gradients, mainly using bromeliad food webs as model systems. 

 

 

Ecosystem linkages

We are interested in tropical water-land interfaces. Allochthonous resources (nutrients, detritus and prey) from a donor ecosystem can subsidy organisms from recipient ecosystems. We are especially interested in how complex life cycle organisms (i.e., those which spend part of their life cycle in water and land) from water interfere in terrestrial ecosystems by subsidying predators (biomass, diversity, abundance), and how subsidized predators affect terrestrial food web structure and dynamics. We manipulate migration of allochthonous prey in water-land boundaries by covering streams, and use stable isotope tools, to test specific hypotheses.

 

 

Human impacts and ecosystem functioning

Climate change is among the most important ecological issue to date. We are interested in how predicted global warming and changes in precipitation can affect species survival, diversity, food web structure and ecosystem functioning. We manipulate rainfall to test nutrient leaching, food web dynamics and ecosystem productivity. We manipulate temperature using controlled heating system in the field to test the effects of warming on (i) predator survival and activity, (ii) predator and prey functional groups, (iii) the magnitude of trophic cascades, (iv) complex networks and trophic pyramids, and (v) ecosystem functioning. We also investigate how global warming affect the role of detritivores and decomposers (bacteria), and their interactions, on detrital processing using tank bromeliads. 

 

 

Ecosystem engineering

We are interested in the effects of ecosystem engineers on species diversity across diverse ecosystems. Manipulative experiments and surveys are conducted using diverse systems: leaf-rolling caterpillars, armadillos etc. 

 

 

Behaviour and evolution

Our group is interested in diverse aspects of animal behaviour. It includes predation risk effects on behaviours of pollinators and herbivores, as well as landscape of fear. Our projects include diverse systems, as predator-pollinator-herbivore and predator-frugivorous interactions. Many predators are cryptic upon their foraging substrates (e.g., flowers), and typically UV reflexion and fluorescence emissions are involved in predator crypsis. We are studying how UV reflexion, fluorescence concentrations and cryptic behaviours of crab spiders (Thomisidae) evolved in the Neotropics (e.g., crab spiders, Thomisidae) using molecular phylogenies and manipulative experiments in the field.

 

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Mutualisms and indirect (biotic) defences in plants

Many plant-predator mutualisms are mediated by plant traits. Our group is interested in specializations of predators mediated by plant traits, and consequences of these interactions for plants and predators. There are many spider species that live specifically associated to certain plant traits. For example, many jumping spiders (e.g., Psecas chapoda) live exclusively associated to bromeliads, and these predators can improve host plant nutrition and growth. Others live associated to plants bearing glandular trichomes (e.g., spiders of the genus Peucetia, Oxyopidae), and these spiders can improve plant fitness by removing phytophages. Other predator-plant relationships are also of interest, including mite-plant interactions mediated by leaf domatia, and ant-plant interactions mediated by domatia and extrafloral nectaries (EFNs).