Potential impacts of invasive crayfish on native crayfish: insights from laboratory experiments

摘要

Despite the extreme diversity of crayfish in the Southeastern United States, many taxa are threatened with extinction due to invasive counterparts. Invasive crayfish alter invaded habitats causing community and population level impacts due to competition, predation and transmission of diseases. We experimentally evaluated the potential impacts of invasive red swamp crayfish (Procambarus clarkii) and virile crayfish (Orconectes virilis) on native Piedmont crayfish (Cambarus sp. C) using size-matched pairs. We tested 1) species-specific aggressive behavior with aggression assays, and 2) survival in sympatry with survival analysis. Both invasive crayfish species tended to express higher levels of aggression compared to the native counterpart. However, we failed to detect any statistically significant differences. During survival experiments, the proportional survival of native Cambarus sp. C in sympatry with invasive O. virilis was significantly lower than that of invasive O. virilis. However, we did not find a significant difference in the proportional survival between invasive P. clarkii and native Cambarus sp. C. These experiments demonstrate inconsistent and limited negative impacts of two invasive crayfish species on a native species, when size-matched. Therefore, in order to make novel and effective decisions in managing these invasive species, it is critical to understand species-specific invasion dynamics and size-dependent potential impacts of invasive crayfish on native taxa.