Contributed Paper

Two-Stage Recovery of Amphibian Assemblages Following Selective Logging of Tropical Forests
GILBERT BAASE ADUM,∗ MARKUS PETER EICHHORN,† WILLIAM ODURO,∗ ¨ CALEB OFORI-BOATENG,∗ ‡ AND MARK-OLIVER RODEL§
∗

Department of Wildlife and Range Management Faculty of Renewable Natural Resources, CANR, KNUST, Kumasi, Ghana †School of Biology, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom ‡Forestry Research Institute of Ghana, KNUST, P.O. Box 63, Kumasi, Ghana §Museum f¨ r Naturkunde, Berlin, Leibniz Institute for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, u Germany

Abstract: There is a lack of quantitative information on the effectiveness of selective-logging practices in ameliorating effects of logging on faunal communities. We conducted a large-scale replicated field study in 3 selectively logged moist semideciduous forests in West Africa at varying times after timber extraction to assess post logging effects on amphibian assemblages. Specifically, we assessed whether the diversity, abundance, and assemblage composition of amphibians changed over time for forest-dependent species and those tolerant of forest disturbance. In 2009, we sampled amphibians in 3 forests (total of 48 study plots, each 2 ha) in southwestern Ghana. In each forest, we established plots in undisturbed forest, recently logged forest, and forest logged 10 and 20 years previously. Logging intensity was constant across sites with 3 trees/ha removed. Recently logged forests supported substantially more species than unlogged forests. This was due to an influx of disturbance-tolerant species after logging. Simultaneously Simpson’s index decreased, with increased in dominance of a few species. As time since logging increased richness of disturbance-tolerant species decreased until 10 years after logging when their composition was indistinguishable from unlogged forests. Simpson’s index increased with time since logging and was indistinguishable from unlogged forest 20 years after logging. Forest specialists decreased after logging and recovered slowly. However, after 20 years amphibian assemblages had returned to a state indistinguishable from that of undisturbed forest in both abundance and composition. These results demonstrate that even with low-intensity logging (≤3 trees/ha) a minimum 20-year rotation of logging is required for effective conservation of amphibian assemblages in moist semideciduous forests. Furthermore, remnant patches of intact forests retained in the landscape and the presence of permanent brooks may aid in the effective recovery of amphibian assemblages.

Keywords: faunal recovery, frogs, Ghana, logged forest, reduced-impact logging
Recuperaci´ n de Ensambles de Anfibios en Dos Etapas Despu´s de la Tala Selectiva de Bosques Tropicales o e

Resumen: Existe una carencia de informaci´ n cuantitativa sobre la efectividad de pr´ cticas de tala selectiva o a en la disminuci´ n de los efectos de la tala sobre comunidades de fauna. Realizamos un estudio de campo o ´ replicado a gran escala en 3 bosques h´ medos semideciduos talados selectivamente en Africa Occidental u en diferentes tiempos despu´s de la extracci´ n de madera para evaluar los efectos posteriores a la tala e o sobre ensambles de anfibios. Espec´ficamente, evaluamos si la diversidad, abundancia y composici´ n del ı o ensamble de anfibios cambiaron en el tiempo en las especies dependientes del bosque y en las tolerantes a la perturbaci´ n del bosque. En 2009 muestreamos anfibios en 3 bosques (un total de 48 parcelas de estudio, de o 2 ha cada una) en el suroeste de Ghana. En cada bosque, establecimos parcelas en bosque no perturbado, bosque recientemente talado y bosque talado 10 y 20 a˜ os antes. La intensidad de la tala fue constante en los n sitios, con la remoci´ n de 3 arboles/ha. Los bosques recientemente talados soportaron sustancialmente mas o ´ especies que los bosques no