Biological invasions of river ecosystems: a flow of implications, challenges, and research opportunities

This article provides an overview of biological invasion of rivers and associated ecosystems. River ecosystems are among the most endangered ecosystems globally, with biological invasions representing one of the main contemporary pressures on their floral and faunal communities, resulting in varied and sometimes unexpected effects on the local economy, human wellbeing, biodiversity, water chemistry or riverbank stability. Moreover, river networks represent critically important ecological corridors in the landscape and their physical structure may affect both the distribution of organisms and inadvertently facilitate the invasion and dispersal of alien species. Following a review of the history and general concepts of biological invasions associated with riverine ecosystems, a range of contemporary examples, pathways of introduction, ecosystem effects and challenges regarding future management and conservation are provided and discussed from around the world. Specific consideration is also given to the implications of invasive species on river biomonitoring activities. We conclude with a discussion regarding future research challenges, opportunities, and new perspectives for gaining a better understanding of biological invasions within riverine ecosystems.