Freshwater ecosystems are exposed to various human activities. The anthropogenic-induced changes in freshwater communities emphasize the need to understand the level of disturbance in these vulnerable ecosystems. The Water Framework Directive (Directive 2000/60/EC) requires that water resources be subjected to ecological assessment to provide basis for the management and restoration of catchments. This can be effectively addressed by information generation on the distribution patterns, spatial relationships and habitat use of freshwater biota. Macrobenthos are one of the important components of the freshwater biota, and are known to be prey items for various organisms, including humans. They are excellent biomonitors of environmental condition being sensitive to disturbance, such as pollution caused by pesticides from agricultural farms. Land use change and longer growing seasons also increase fertilizer use with subsequent leaching towards watercourses, rivers and lakes, increasing the risk of eutrophication. Invasive macrobenthos, e.g. golden apple snail, can cause damage to nearby crop fields, and some can even outcompete native species causing local extinctions. There are very limited data on the community patterns and ecological dynamics of macrobenthos in tropical freshwater crater lakes. The seven lakes of San Pablo City, are ideal sites to examine biodiversity profiles of macrobenthos across the habitat gradients (disturbed to pristine conditions). Previous studies on the lakes only focused plankton diversity (LLDA, 2005), fish culture (Quilang et al., 2007; Santiago, 1994), and potential of paleolimnological approach (Legaspi et al., 2015). However, there are very limited researches available on the diversity and ecology of macrobenthos across the seven lakes. Thus, the baseline information that will be generated in this study will further equip local LGUs to design a more wholistic conservation and management strategies for the freshwater resources of the seven lakes.

This is the first comprehensive assessment of macrobenthic community in the seven lakes of San Pablo. Previous studies on the seven lakes have focused on the fisheries, phyto and zooplankton diversity, and physico-chemical perturbations. This study aims to assess the freshwater macrobenthos diversity among the seven lakes of San Pablo City, Laguna Province. It specifically aims to determine the biodiversity patterns of native and introduced/invasive macrobenthos and to relate the community with selected environmental variables.