Species Dynamics and Restoration in Rare Serpentine Grasslands under Global Change

Abstract

Conserving rare serpentine grasslands is a challenge with ongoing nitrogen deposition. Nutrient-poor patches are fertilized by nitrogen-rich smog and exotic grasses can rapidly spread. Water resources are also being altered in this system via climate change. Using a greenhouse experiment and a long-term survey, I test how rainfall variability interacts with nitrogen deposition to shift native patches to an exotic state. We found that wetter years interact with intermediate nitrogen to drive invasion. Restoring exotic-dominated patches is difficult once an established layer of litter reasserts exotic dominance. Capitalizing on a long-term dataset, I test burning and grazing as restoration tools to promote native forb recovery. I found that a burn and continual grazing is effective in controlling exotic cover and litter levels to restore invaded patches to a native state. As global change continues to reinforce exotic dominance, continual and well-timed management is necessary to maintain native serpentine grasslands.This thesis includes both previously published/unpublished and co-authored material.