Peri-village Forest Retains the Highest Tree Diversity: Comparison of Forest Communities along a Livelihood Intensity Gradient in Southeast Cameroon

Abstract

We compared tree diversity (diameter at breast height, DBH ≥ 10 cm), functional traits, and species composition among zones with different intensity levels of human activity in southeast Cameroon. The highest diversity, evaluated as species richness and Shannon's index, was observed in peri-village forest, where shifting cultivation was practiced. We detected little difference in functional traits (regeneration guild, leaf phenology, seed dispersal mode, woody density, basal area, and aboveground biomass) among zones for the tree species observed. Only a slight increase in the proportion of pioneer species was observed in peri-village forest, and species turnover was not detected. Previous studies have indicated that disturbances caused by creating agricultural fields introduce pioneer species and reduce tree species diversity. These studies compared diversity in fields or fallows with that in old-growth forests, which likely overestimated the negative impact of shifting cultivation on tree diversity. In contrast, we found that if shifting cultivation is practiced at moderate intensity, it can increase and maintain tree diversity without altering the quality of a landscape consisting of a mosaic of fields, young secondary forest, old secondary forest, and old-growth forest.