Population Ecology and Genetic Diversity of the Invasive Alien Species Procambarus clarkii in Lake Trasimeno (Italy)

SIMPLE SUMMARY: The population of Procambarus clarkii was surveyed twenty years after its introduction into Lake Trasimeno (Central Italy), investigating both ecological and genetic aspects. Our results confirmed that P. clarkii is well acclimatized with a stable population structure, mainly characterized by a unique mitochondrial lineage, suggesting that a single introduction event may have occurred in the lake, complemented by secondary events. ABSTRACT: The deliberate or accidental introduction of invasive alien species (IAS) causes negative ecological and economic impacts altering ecosystem processes, imperiling native species and causing damage to human endeavors. A monthly monitoring program was performed in Lake Trasimeno (Central Italy) from July 2018 to July 2019 in order to provide an upgrade of the population ecology of Procambarus clarkii and to assess the genetic diversity by analyzing the relationships among mitochondrial DNA diversity. Our results confirmed that P. clarkii is well acclimatized in the lake, revealing a stable population structure favored by the resources and conditions typical of this ecosystem, which seem to be optimal for the maintenance of the species. Four distinct mitochondrial haplotypes were detected, but one of them was clearly overrepresented (76%), suggesting that a single predominant introduction event may have occurred in this area, likely followed by secondary events. The identification of the typical genetic variants provides a better understanding of the evolutionary scenarios of P. clarkii in this biotope and it can be helpful in management plans concerning the expanding populations of this invasive alien species.