MECHANISMS AND IMPACTS OF LAND-USE CHANGE ON FRESHWATER FISHES IN SUNDALAND

Freshwater fishes of Sundaland face threats from deforestation, yet the associated impacts and mechanisms remain inadequately understood. In this context, I sought to address the following: 1) Which are the priority regions for freshwater fish conservation in Sundaland?; 2) What are the impacts of land-use change on fish communities and food webs?; and 3) What are the mechanisms controlling these impacts? Priority ecoregions within Sundaland were identified using trait-based criteria, and simulated species losses were found to have relatively mild impacts on trait richness. Next, I found that mouth positions mediate effects of riparian vegetation on fish occurrences in oil palm streams. Following this, I validated and applied amino acid isotope techniques to investigate land-use impacts on food webs across drainages in Sundaland. This revealed declines in trophic redundancy with increasing disturbance. Taken together, my findings suggest that while Sundaic ichthyofauna may possess short-term resilience to land-use driven species declines.

Author dc:creator

• KENNY CHUA WEI JIE

• deforestation, tropical rainforest, oil palm, streams, stable isotopes, food webs