PROTECTING AQUATIC DIVERSITY IN DEFORESTED TROPICAL LANDSCAPES

Abstract

Global biodiversity is being lost due to extensive, anthropogenic land-use change. In Southeast Asia, biodiversity-rich forests are being logged and converted to oil-palm monocultures. The impacts of land-use change on freshwater ecosystems and biodiversity, remains largely understudied and poorly understood. I investigated the impacts of logging and conversion of tropical forest in 35 streams across a land-use gradient on freshwater fishes. There are four key findings from this research. (1) Any modification of primary rainforest is associated with a loss of fish species and functional richness. (2) Streams in oil-palm plantations with riparian reserves of high forest quality, and a width of > 64m on either side, retain higher species richness and higher abundances of individual fish species. (3) Although relatively low in species richness, streams in oil-palm plantations retain high biomass of freshwater fish that is readily captured using cast nets, providing an important protein source and supplementary income to local communities. (4) An extreme El-Niño drought interacted antagonistically with land-use change, reducing the capture rate of N. everetti, in my study area.