Associations between hydrological connectivity and resource partitioning among sympatric gar species (Lepisosteidae) in a Texas river and associated oxbows

摘要: The middle Brazos River, located in east-central Texas, is a meandering lowland river with many oxbow lakes on its flood plain. Flood dynamics of the River are aseasonal, and faunal exchange during lateral connections main channel oxbows pulse-like occurs only floods that may be months or years apart. Patterns resource use among sympatric gar species (Lepisosteus oculatus, Lepisosteus osseus Atractosteus spatula) associated river-flood plain connectivity were studied for period 2 (May 2003 to May 2005). first year was relatively dry yielding few connections, whereas second wet resulting more frequent connections. This study focused habitat diet partitioning three habitats different connection frequencies an active site. Overall, 684 gars collected experimental gillnets: 19 A. spatula (alligator gar), 374 L. oculatus (spotted gar) 291 (longnose gar). There strong between spotted longnose gars, which 98% captured 84% channel. Hydrology did not appear affect partitioning, although abundance significantly increased year. Diet overlap high gars. Temporal variation influenced by pulses connected channel, allowed predators their prey move habitats.