Understanding the single and combined effects of co-occurring stressors: white-tailed deer, invasive earthworms and invasive plants.
Dávalos1, A., A. Dobson2, L. Eierman1 & T. McCay3.
Forests in northeastern United States experience multiple, co-occurring stressors. Understanding if each stressor is passenger, the driver, or both driver and passenger of change is critical to effective and efficient management. We used a multiple stressor framework to evaluate the single and interactive effects of white-tailed deer, invasive earthworms and the invasive grass, Microstegium vimineum on native vegetation. We paired open and fenced plots along a gradient of worm invasion and at sites with varying M. vimineum abundance. We transplanted seedlings of four native plant species at each site and assessed their survival and growth 2020-2022. We found negative impacts of invasive jumping worms on red oak survival and synergistic effects among study factors on all plant species. In combination, the survival and growth of seedlings significantly decreased when transplants experienced a combination of impacts, suggesting that focusing on the removal of one stressor might mitigate negative impacts. The sentinel approached proved an effective method to gauge impacts of multiple stressors and could be reliably implemented by landowners and land managers.
1Department of Biological Sciences, SUNY Cortland
2Yale School of the Environment, Yale University
3Department of Biology, Colgate University