title: Trophic flexibility and the persistence of understory birds in intensively logged rainforest.
abstract: Effects of logging on species composition in tropical rainforests are well known but may fail to reveal key changes in species interactions. We used nitrogen stable-isotope analysis of 73 species of understory birds to quantify trophic responses to repeated intensive logging of rainforest in northern Borneo and to test 4 hypotheses: logging has significant effects on trophic positions and trophic-niche widths of species, and the persistence of species in degraded forest is related to their trophic positions and trophic-niche widths in primary forest. Species fed from higher up the food chain and had narrower trophic-niche widths in degraded forest. Species with narrow trophic-niche widths in primary forest were less likely to persist after logging, a result that indicates a higher vulnerability of dietary specialists to local extinction following habitat disturbance. Persistence of species in degraded forest was not related to a species' trophic position. These results indicate changes in trophic organization that were not apparent from changes in species composition and highlight the importance of focusing on trophic flexibility over the prevailing emphasis on membership of static feeding guilds. Our results thus support the notion that alterations to trophic organization and interactions within tropical forests may be a pervasive and functionally important hidden effect of forest degradation.
authors: Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom; School of Marine and Tropical Biology, James Cook University, Cairns, Queensland, 4878, Australia. dave.edwards@jcu.edu.au.
authors: David P
authors: DP
authors: Edwards
authors: Paul
authors: P
authors: Woodcock
authors: Rob J
authors: RJ
authors: Newton
authors: Felicity A
authors: FA
authors: Edwards
authors: David J R
authors: DJ
authors: Andrews
authors: Teegan D S
authors: TD
authors: Docherty
authors: Simon L
authors: SL
authors: Mitchell
authors: Takahiro
authors: T
authors: Ota
authors: Suzan
authors: S
authors: Benedick
authors: Simon H
authors: SH
authors: Bottrell
authors: Keith C
authors: KC
authors: Hamer
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001717:Birds / Q000502:physiology*; D001893:Borneo; D003247:Conservation of Natural Resources; D017753:Ecosystem; D056727:Endangered Species; D005247:Feeding Behavior; D020387:Food Chain; D009587:Nitrogen Isotopes; D014329:Tropical Climate
chemical_list: D009587:Nitrogen Isotopes
keywords: community resilience; diet; dieta; ecosystem functioning; extinction risk; food webs; funcionamiento del ecosistema; functional guilds; gremios funcionales; redes alimenticias; resiliencia de la comunidad; riesgo de extinción; selective logging; tala selectiva