Over the past decade, research has clarified the definition of invasive species’ impacts and developed metrics for quantifying and predicting ecological impacts. There is a temporal bias in invasion impact studies, whereby most measurements are collected over short timescales (< 1 year), with very little focus on impacts over longer timescales. Independent of the timescale, researchers measure impacts at different biological levels of organization (e.g., genetic, individual, population, community, or ecosystem; hereafter, impact type). Here, we ask whether there are temporal biases in the types of impact that are studied in invasion ecology. To answer this question, we compiled a database of nearly 2,000 invasion impact studies. We categorized each study according to impact type and duration. We then characterized the variation in these categories to identify potential bias in the focal impact across short and long-term research.
Our results highlight a significant temporal bias in the types of impact studied in invasion ecology research. Short-term studies focused on population-level impacts while long-term research assessed a greater amount of community-level effects than expected. This result points to a disconnect between the impacts investigated for most invasion ecology studies (i.e. short-term) and the focal impact of long-term studies. The consequence of this temporal bias in impact type is that researchers may not account for lower or higher-order impacts in their study system. By analyzing a variety of biological levels across timescales we will be able to better quantify and manage the dynamic impacts of invasive species. Demonstrating clear impacts is particularly important at a time when invasion ecology faces increased skepticism surrounding invasive species’ impacts. Future research should emphasize a multi-scale impact approach, perhaps by using natural experiments involving recent invaders to assess several impact types across timescales.