Invasion success of a freshwater fish corresponds to low dissolved oxygen and diminished riparian integrity

Invasions are a common occurrence in many ecosystems but predicting the establishment and impacts of the invader can be difficult. Understanding how and why invasion progresses can improve efforts to prevent spread and mitigate invasion impacts. Recent efforts have sought to design forecasting methods to identify the environmental context of invasions to help identify areas vulnerable to future invasions. We suggest there are predictable environmental characteristics that affect the probability of successful establishment of invasive species. Specifically, we hypothesize that degraded habitat and water quality facilitate successful invasion, as indicated by high abundances of the invader, due to multiple interacting stressors in the invaded ecosystem. To test this hypothesis, we assessed seven rivers in a temperate region of North America undergoing round goby (Neogobius melanostomus) invasion via fish surveys, water quality assessments, and land cover analyses over three years (2015–2017). Mixed effect random forest models were used to identify commonalities among biotic, physical, chemical, and landscape parameters associated with the relative abundance of round goby among fish assemblages. Low dissolved oxygen and lower proportions of wetland and wetted area land cover in the riparian corridors were associated with highly invaded sites. Results were consistent with prior works suggesting identification of sites with diminished riparian integrity and water quality may help prioritize stream reaches for monitoring to aid in early detection.