Ecological and potential socioeconomic impacts of two globally-invasive crayfish

Quantifying the impacts of invasive species, relative to native analogues, is crucial for management and policy development. Two freshwater crayfish species global concern, Cherax quadricarinatus Procambarus clarkii , have established populations across Africa. Negative on biodiversity socioeconomic been documented in other continents; however, there a paucity information from Africa C. . To fill this literature gap, study used laboratory experiments determine potential ecological conferred by functionally similar analogue, river crab Potamonautes perlatus two static, but different resources. Consumption rates were derived three focal consuming macrophyte Potamogeton nodosus dead Oreochromis mossambicus under temperatures regimes (19 °C 28 °C), representing summer winter seasons Southern Africa, with maximum feeding rate infer impact. represents ecologically-important nutrient cycling macrophytes, as well habitat juvenile fish, whereas O. was proxy fish catches artisanal gillnet fisheries often scavenged crayfish. both resources all decapods increased temperature. However, showed impact trends where P. had significantly higher consumption macrophytes than regardless temperature same seen, scavenging fish. Crayfish introductions clearly highly destructive invaded systems compared crabs. The disparity between resource use emphasises necessity appropriate geographical species-specific contexts avoid erroneous conclusions generalised risk assessments. Derived can be rapid assessments comparisons invasion cores.