title: Using avian functional traits to assess the impact of land-cover change on ecosystem processes linked to resilience in tropical forests.
abstract: Vertebrates perform key roles in ecosystem processes via trophic interactions with plants and insects, but the response of these interactions to environmental change is difficult to quantify in complex systems, such as tropical forests. Here, we use the functional trait structure of Amazonian forest bird assemblages to explore the impacts of land-cover change on two ecosystem processes: seed dispersal and insect predation. We show that trait structure in assemblages of frugivorous and insectivorous birds remained stable after primary forests were subjected to logging and fire events, but that further intensification of human land use substantially reduced the functional diversity and dispersion of traits, and resulted in communities that occupied a different region of trait space. These effects were only partially reversed in regenerating secondary forests. Our findings suggest that local extinctions caused by the loss and degradation of tropical forest are non-random with respect to functional traits, thus disrupting the network of trophic interactions regulating seed dispersal by forest birds and herbivory by insects, with important implications for the structure and resilience of human-modified tropical forests. Furthermore, our results illustrate how quantitative functional traits for specific guilds can provide a range of metrics for estimating the contribution of biodiversity to ecosystem processes, and the response of such processes to land-cover change.
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK tpbregman@gmail.com.|Global Canopy Programme, 23 Park End Street, Oxford OX1 1HU, UK.
authors.forename: Tom P
authors.initials: TP
authors.lastname: Bregman
authors.affiliation: Division of Biology and Conservation Ecology, School of Science and the Environment, Manchester Metropolitan University, Manchester M1 5GD, UK.|Cornell Laboratory of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA.|Departamento de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará CEP 66040-170, Brazil.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Lees
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.|School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
authors.forename: Hannah E A
authors.initials: HE
authors.lastname: MacGregor
authors.affiliation: Curso de Pós-graduação de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará CEP 66040-170, Brazil.|Programa de Pós-graduação em Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Bianca
authors.initials: B
authors.lastname: Darski
authors.affiliation: Cornell Laboratory of Ornithology, Cornell University, 159 Sapsucker Woods Road, Ithaca, NY 14850, USA.|Departamento de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará CEP 66040-170, Brazil.
authors.forename: Nárgila G
authors.initials: NG
authors.lastname: de Moura
authors.affiliation: Departamento de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará CEP 66040-170, Brazil.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Aleixo
authors.affiliation: Departamento de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará CEP 66040-170, Brazil.|Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Jos
authors.initials: J
authors.lastname: Barlow
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK j.tobias@imperial.ac.uk.|Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK.
authors.forename: Joseph A
authors.identifier: 0000-0003-2429-6179
authors.initials: JA
authors.lastname: Tobias
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000145:classification*; D020387:Food Chain; D065928:Forests; D060434:Herbivory; D006802:Human Activities; D006801:Humans; D007313:Insecta; D058614:Seed Dispersal; D014329:Tropical Climate
keywords: biodiversity; biotic interactions; defaunation; ecosystem processes; land-use change; seed dispersal