Impact of a set of environmental variables on the leaf litter breakdown rate in natural streams of the equatorial forest in Cameroon

Abstract

This study assessed the environmental factors underlying the leaf litter decomposition rate in streams in the equatorial rainforest of Cameroon. To reach this goal we used the litterbag method and dead leaves of Funtumia africana (Benth) Stapf (Apocynaceae)in seven natural streams. Concomitantly, we measured biological (fungi and macroinvertebrates) and environmental parameters to highlight those that control the leaf litter breakdown rates. The breakdown rates ranged from 0.035 to 0.056 with an average of 0.042 ± 0.006 in the coarse-mesh litterbags ( K c ) and from 0.018 to 0.059 with an average of 0.037 ± 0.01 in the fine-mesh litterbags ( K f ). No significant difference was observed between seasons or sites, except for K f . . As in other tropical rainforests in South America and Asia, the breakdown rates are mainly resulted from microbial activity; the contribution of shredders was negligible, as confirmed by the K c to K f ratio and the litter fragmentation rate λ F . Among environmental factors, only the distance from the source and the pH were positively correlated with the leaf litter breakdown rates.