Trophic Flexibility and the Persistence of Understory Birds in Intensively Logged Rainforest

• Published in: Conservation biology 2013-10, Vol.27 (5), p.1079-1086
• Main Authors: EDWARDS, DAVID P., WOODCOCK, PAUL, NEWTON, ROB J., EDWARDS, FELICITY A., ANDREWS, DAVID J. R., DOCHERTY, TEEGAN D. S., MITCHELL, SIMON L., OTA, TAKAHIRO, BENEDICK, SUZAN, BOTTRELL, SIMON H., HAMER, KEITH C.
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Autoecology; Aves; Biological and medical sciences; Birds - physiology; Borneo; community resilience; Conservation of Natural Resources; Conservation, protection and management of environment and wildlife; diet; dieta; Ecosystem; ecosystem functioning; Endangered Species; extinction risk; Feeding Behavior; Food Chain; food webs; Forestry; funcionamiento del ecosistema; functional guilds; Fundamental and applied biological sciences. Psychology; General aspects; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; gremios funcionales; Isotopes; Nitrogen; Nitrogen Isotopes; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Rainforests; redes alimenticias; resiliencia de la comunidad; riesgo de extinción; selective logging; tala selectiva; Tropical Climate; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/cobi.12059

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. Los efectos de la tala sobre la composición de especies en bosques lluviosos tropicales son bien conocidos pero pueden fallar en la revelación de cambios clave en las interacciones de especies. Utilizamos análisis de isotopos estables de nitrógeno de 73 especies de aves de sotobosque para cuantificar las respuestas tróficas a la tala intensiva del bosque lluvioso en el norte de Borneo y para probar 4 hipótesis: la tala tiene efectos significativos sobre posiciones tróficas y la amplitud de nicho de las especies, y la persistencia de especies en el bosque degradado está relacionado con sus posiciones tróficas y amplitud de nicho trófico en el bosque primario. Las especies se alimentaron más arriba en la cadena trófica y tuvieron nichos más angostos en el bosque degradado. Las especies con nichos angostos en bosques primarios tuvieron menor probabilidad de persistir después de la tala, resultado que indica que especies con dietas especializadas tienen mayor vulnerabilidad a la extinción local después de una perturbación de hábitat. La persistencia de especies en bosqu