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theses

Due to invasive species’ substantial influence on human health, the economy, and the natural environment, invasion ecologists have committed substantial effort to study the variety of impacts caused by invasive species. Impact research has consistently increased since the late 1990s when ecologists published theoretical work on early metrics for calculating impacts. Despite the clear societal benefit of studying and understanding impacts, funding to study impacts are limited. Biases in the taxa, ecosystems, and spatial scales that are studied may undermine our ability to predict invasive species effects. However, there are no syntheses that quantify how these biases influence impact research.
In my dissertation, I investigate patterns in how researchers collect and then publish data about invasive species impacts. In my first chapter, I used a metric for quantifying invasive species impacts to predict the potential distributional range for a recently introduced bird in North America. My analyses suggest that the Pin-tailed Whydah has a substantial amount of available habitat to spread within California and the Antilles. In my second chapter, I conducted a systematic review to identify the impacts, taxa, ecosystems, and spatiotemporal scales that receive a substantial proportion of impact research. These results suggest that research efforts often focus on a few well-known invasives in forests or on islands while most species have only a single documented impact. In my third chapter, I conducted a cumulative meta-analysis to identify patterns in published evidence accrual for invasive species impacts on richness. In general, the earliest published research on impacts suggests the largest average richness impacts, and repeated studies on the same taxa or in the same ecosystems generally suggest negative, but more moderate average impacts. Taken together, this dissertation highlights the value of producing primary research on invasive species impacts. It also uses syntheses to identify critical research gaps or areas where sufficient evidence has accrued to answer questions about invasive species’ impacts on diversity.

ETD_9634

Ph.D.

Includes bibliographical references

doi:10.7282/t3-9qca-x929

ETD doctoral

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