Landscape features correlate with spatial distribution of red-swamp crayfish Procambarus clarkii in a network of ponds

The red-swamp crayfish Procambarus clarkii has become the most cosmopolitan freshwater crayfish species in the world as a result of numerous intentional and accidental introductions. This species was introduced approximately 30 years ago into the Briere marshes (France) where it has spread rapidly since this date. The colonization of P. clarkii in the network of ponds surrounding the Briere marshes is poorly documented despite the high conservation value of such ecosystems. Here, we describe the spatial distribution of P. clarkii in a subset of this network of ponds. We also test whether the presence of P. clarkii is explained by three landscape metrics that measure the level of isolation of a pond with other waterbodies (marshes, streams or ponds). Sixty-nine ponds were sampled in spring 2010 using baited funnel traps. P. clarkii was detected in 20% of the sampled ponds. Moreover P. clarkii was most likely to be present in ponds in close proximity of marshes and a stream. These findings suggest that colonization of a pond depends primarily on the proximity to existing populations, despite the efficiency of overland dispersal of P. clarkii.