Forest fragmentation and selective logging have inconsistent effects on multiple animal-mediated ecosystem processes in a tropical forest

  • Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the functionality of tropical forests can be maintained in moderately disturbed forest fragments. Conservation concepts for tropical forests should thus include not only remaining pristine forests but also functionally viable forest remnants.

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Author:Matthias Schleuning, Nina Farwig, Marcell K. Peters, Thomas Bergsdorf, Bärbel Bleher, Roland Brandl, Helmut Dalitz, Georg Fischer, Wolfram M. Freund, Mary Wanjiku Gikungu, Melanie Hagen, Francisco Hita Garcia, Godfrey Hurbby Kagezi, Manfred Kaib, Manfred Kraemer, Tobias Lung, Clas M. Naumann, Gertrud Schaab, Mathias Templin, Dana Uster, J. Wolfgang Wägele, Katrin Böhning-GaeseORCiDGND
Pubmed Id:
Parent Title (English):PLoS One
Place of publication:Lawrence, Kan.
Document Type:Article
Date of Publication (online):2011/11/16
Year of first Publication:2011
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2011/12/28
Issue:11: e27785
Page Number:12
First Page:1
Last Page:12
Institutes:Biowissenschaften / Biowissenschaften
Angeschlossene und kooperierende Institutionen / Senckenbergische Naturforschende Gesellschaft
Fachübergreifende Einrichtungen / Biodiversität und Klima Forschungszentrum (BiK-F)
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung 3.0