AoB PLANTS

Plant communities in harsh sites are less invaded: a summary of observations and proposed explanations

Due to seasonal inundation, these vernal pools (yellow) in central California have harsher conditions than the surrounding grassland matrix. Virtually all of the plants in the grassland are non-native invasive species, while the pools are largely devoid of non-natives.  Photo credit: Truman Young, UC Davis.
Due to seasonal inundation, these vernal pools (yellow) in central California have harsher conditions than the surrounding grassland matrix. Virtually all of the plants in the grassland are non-native invasive species, while the pools are largely devoid of non-natives.
Photo credit: Truman Young, UC Davis.

Within the invasion ecology literature, it is often noted that abiotically stressful environments are typically less invaded by non-native plants than nearby less-stressful environments. However, until now no one had collected and summarized examples of this pattern. In a new paper published in AoB PLANTS, Zefferman et al. first compile evidence that plant communities in many harsh habitats are less invaded, and then synthesize possible explanations for this pattern. They discuss that harsh sites may be less invaded because, compared to moderate sites, they may receive lower propagule pressure, particularly from well-suited plants, and because their abiotic and biotic characteristics may make them inherently more resistant to invasion.