Nicholas M. Fountain-Jones, Gregory J. Jordan, Christopher Burridge, Timothy J. Wardlaw, Thomas P. Baker, Lynette Forster, Morgana Petersfield and Susan C. Baker
Beetles are not only the most species rich group of animals, but are also very diverse in function, ranging from predators and parasites to herbivores and decomposers breaking down plant material. In forest litter, beetle predators and decomposers often occupy the same patch of habitat, but how each community’s functional traits (traits of a species that can be linked to their ecological roles) respond and recover after disturbance is poorly known. Understanding to what extent functional traits of co-occuring trophic groups are constrained by evolutionary relationships (i.e., do beetles with long antennae have long antennae because their ancestors did?) can provide insights into the mechanisms of how communities assemble and recover.
We compared the functional traits and phylogenetic data (relatedness) for 133 beetle species (60 predators and 73 decomposers) from forest sites ~7 years, ~27 years and ~45 years after logging, and in neighbouring mature forest plots. We found that functional trait composition of predator communities had recovered to mature forest values after ~45 years, and this was before the communities contained even most of the species characteristic of mature forest. In contrast, for decomposers, neither species nor functional traits had recovered to mature forest values by this time. Not only were the patterns of recovery different between the trophic groups, the traits that responded to forest age, and the extent to which these traits were constrained by evolution, varied as well. For decomposers, for example, beetles were on average darker in color in ~45 year-old forest than in ~7 year-old forests, yet this trait did not differ for predators. Predator traits were also more constrained by evolutionary history compared to the decomposers. This study demonstrates that recovery patterns after logging can vary with trophic group even for the same group of animals. Furthermore, incoporating functional trait and phylogenetic data can help better understand the mechanisms underpinning these complex but diverse communities.
Image caption: Image provided by authors.
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