Linking fish colonization rates and water level change in littoral habitats of a Venezuelan floodplain river

Change in water level during the annual hydrologic cycle of tropical floodplain rivers results in continuous disassembly and reassembly of faunal communities in littoral habitat patches. As such, the rate of water level change should influence colonization rates of vagile organisms among habitat patches. We experimentally tested this hypothesis in a Venezuela floodplain river using artificial rocky patches as sampling units, water level change as the independent variable, and total number of individual fish that colonized a patch as the response variable. Water level significantly affected the total number of individuals that colonized patch habitats, i.e., rapidly receding waters were associated with higher colonization rates. Results suggest that water-level recession directly affects community assembly by influencing the rate at which individuals abandon and colonize local habitat patches.