Dissertation Research: The effects of invasive plant species on biodiversity across spatial scales

Washington University, Saint Louis MO

Investigators

Abstract

Humans are intentionally and unintentionally transporting species around the globe at an increasing rate. Some of these transported species become highly invasive and cause large declines in the diversity of native species. At the same time, some researchers note that invasive species, specifically invasive plant species, rarely cause native species to go extinct and are rather harmless. These contrasting views have prompted people to question the environmental harm caused by invasive plants. This research aims to synthesize these seemingly conflicting ideas about the effects of invasive plants on biodiversity. The hypothesis of this research is that the effect of invasive plants on biodiversity changes depending on spatial scale. Specifically, invasive plants have larger negative effects on diversity at small scales than broad scales. Scale-dependent effects are expected if invasive plants have larger negative effects on the abundance of common plant species than rare plant species in a community. This proposal tests the hypothesis of scale-dependence by conducting (1) a quantitative review of studies that examine the effect of invasive plants at different spatial scales, (2) field surveys of plant-invaded communities across the U.S., (3) demography of common and rare plant species that are affected by invasive plants, and (4) experiments to test which mechanisms cause differences in the effect of invasive plants at different spatial scales. This research integrates studies on communities and populations to understand the effects of invasive plants on native communities and provides a framework for how to understand current and future loss of biodiversity. Broader impacts: This proposal will provide research and mentoring opportunities for undergraduate women and high school students during the data collection for this research. Further educational outreach will involve teaching ecology and invasive species modules at urban schools and day-long workshops for teachers and high school students. This research will continue to provide opportunities for undergraduates and K-12 students, particularly students from underrepresented backgrounds. Public education will continue to be important through public articles and recommendations for restoration and invasive species management at local natural areas.