Constraints on the functional trait space of aquatic invertebrates in bromeliads

We examined the ecological strategies and constraints underlying the realized trait space of aquatic invertebrates, using data on 12 functional traits of 852 taxa collected in tank bromeliads from Mexico to Argentina. The major axes of trait variation represented life history strategies optimizing resource use, and anti-predator adaptations. There was evidence for trophic, habitat, defence and life history niche axes. Bromeliad invertebrates only occupied 17-24% of the potential space within these dimensions, due to greater concentrations than predicted under uniform or normal distributions. Trait combinations aggregated taxa by family and then by order, suggesting that niche conservatism is a widespread mechanism in the diversification of ecological strategies.