Constraints on the functional trait space of aquatic invertebrates in bromeliads

PILLAR, VD.; MACDONALD, AAM.; GUZMAN, LM.; ROMERO, GQ.; CÉRÉGHINO, R.; DEBASTIANI, VJ.; DE OMENA, PM.; SRIVASTAVA, DS.; FARJALLA, VF.; CORBARA, B.; BARBERIS, IM.; DÉZERALD, O.; OSPINA BAUTISTA, F.; LEROY, C.; TALAGA, S.; KRATINA, P.; TRZCINSKI, MK.; MONTERO, GA.; MARINO, NAC.; GONÇALVES, AZ.; RICHARDSON, MJ.; RICHARDSON, BA.; PETERMANN, J.; GILBERT, B.; PICCOLI, GCO.; JOCQUÉ, M.

FUNCTIONAL ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 p. 1 - 13

0269-8463

ABSTRACT. 1. Functional traits are increasingly being used in predictive models that link environmental drivers with community structure, or community structure with ecosystem functioning. A prerequisite is however to produce robust sets of continuous axes of trait variation, and to understand the ecological and evolutionary constraints that result in the functional trait space occupied by interacting species. 2. Most of our current understanding of the functional trait space of species pools has come from studies of plants. We examined the ecological strategies and constraints underlying the realized trait space of aquatic invertebrates, using data on 12 functional traits of 852 invertebrate taxa collected from the water-filled leaves of tank bromeliads at 22 neotropical locations. Principal Component Analysis was used to reduce trait dimensionality to significant axes of trait variation that represent ecological strategies. The proportion of potential trait space that is actually occupied by invertebrate taxa was compared to null expectations. Permutational Analyses of Variance were used to test whether functional trait combinations were clade-dependent.3. The major axes of trait variation (trophic, habitat, morphological defence, life cycle) represented life history strategies to optimize resource use in space and time, and the outcomes of an evolutionary arms race between predators and prey. Bromeliad invertebrates occupied a small fraction (~17-24%) of the potential space offered by these dimensions, due to greater concentrations in trait space than predicted under uniform or normal distributions. Trait combinations usually aggregated taxa by family and then by order, suggesting that niche conservatism is a widespread mechanism in the diversification of ecological strategies. On the other hand, empty areas in trait space represented ?gaps? between major phyla that arose from biological innovations, as well as trait combinations that are unviable in the bromeliad ecosystem. 4. Our results shed new light on the mechanisms underlying the diversification of functional traits of aquatic invertebrates. They also provide an important template to establish trait-environment relationships across major lineages and food web components in forthcoming analyses of the processes underlying functional diversity in relation to spatial, environmental and biotic factors.