Fish Assemblage Composition Within the Floodplain Habitat Mosaic of a Tropical Lake (tonle Sap, Cambodia)

1. Understanding how habitat heterogeneity is linked to biodiversity patterns within flood–pulse catchments is needed for their effective conservation. To study those communities, researchers have begun to explore how local environmen‐ tal factors influence species composition patterns at relatively fine scales within complex habitat mosaics. However, a robust description of the link between com‐ munities’ composition and their floodplain habitat characteristics remains poorly articulated. 2. In the Tonle Sap Lake (TSL) of Cambodia, we evaluated whether mesohabitat‐scale (1–5 km) factors throughout the floodplain structured the fish assemblage tempo‐ rally and spatially. First, we determined whether TSL fish assemblage changed seasonally and, if so, what assemblage components were driving that change. Second, we determined whether environmental factors structured fish compo‐ sition across floodplain mesohabitat patches during the wet season. Third, we evaluated whether dominant species displayed affinities for specific areas within the floodplain during the wet season, potentially identifying critical mesohabitat patches for the fish assemblage.