A Young lab review paper headed up by Emily Zefferman and Jens T. Stevens, and developed along with several lab members and lab affiliates, has been made available online! Here is a preview, and you can find the whole manuscript online at: Plant communities in harsh sites are less invaded: a summary of observations and proposed explanations.
Plant communities in harsh sites are less invaded: a summary of observations and proposed explanations
Emily Zefferman, Jens T. Stevens, Grace K. Charles, Mila Dunbar-Irwin, Taraneh Emam, Stephen Fick, Laura Morales, Kristina M. Wolf, Derek J. N. Young, Truman P. Young
Plant communities in abiotically stressful, or ‘harsh,’ habitats have been reported to be less invaded by non-native species than those in more moderate habitats. Here, we synthesize descriptive and experimental evidence for low levels of invasion in habitats characterized by a variety of environmental stressors: low nitrogen; low phosphorus; saline, sodic, or alkaline soils; serpentine soils; low soil moisture; shallow/rocky soils; temporary inundation; high shade; high elevation; and high latitude. We then discuss major categories of hypotheses to explain this pattern: the propagule limitation mechanism suggests invasion of harsh sites is limited by relatively low arrival rates of propagules compared to more moderate habitats, while invasion resistance mechanisms suggest harsh habitats are inherently less invasible due to stressful abiotic conditions and/or increased effects of biotic resistance from resident organisms. Both propagule limitation and invasion resistance may simultaneously contribute to low invadedness of harsh sites, but the management implications of these mechanisms differ. If propagule limitation is more important, managers should focus on reducing the likelihood of propagule introductions. If invasion resistance mechanisms are in play, managers should focus on restoring or maintaining harsh conditions at a site to reduce invasibility.
KEYWORDS: environmental stress; invasibility; invasive/exotic plants; native plant refuges; propagule pressure; resource availability