Conservation potential of artificial water bodies for fish communities on a heavily modified agricultural floodplain

With tropical floodplain wetlands ranking among the world's most threatened ecosystems, artificial water bodies are an often under-appreciated potential conservation resource for aquatic fauna in these heavily modified environments. This paper describes the fish communities in 27 artificial water bodies having three different management and design types (ditch recycle pits, generic recycle pits and constructed wetlands) on a heavily modified floodplain in northern Australia. In these artificial water bodies, constructed wetlands housed significantly higher mean native fish diversity, followed by generic recycle pits and then ditches, where communities were numerically dominated by invasive, non-native fishes. Environmental parameters such as water body depth and riparian zone condition were the descriptors that best explained fish community composition across water bodies. Comparison with collated fish survey data representing broader floodplain γ-diversity showed that >70% of regional fish diversity was housed in artificial water bodies, with constructed wetlands alone accounting for 68% of freshwater species known from the floodplain. In addition, site (α) diversity of native species in constructed wetlands did not differ from site diversity in remnant, relatively intact natural water bodies, and was significantly greater than species diversity in heavily degraded, natural floodplain habitats. Study results provide strong evidence that artificial water bodies can make useful contributions to biodiversity conservation by providing artificial habitat in a floodplain environment dominated by agriculture