Tree seedling responses to multiple environmental stresses: Interactive effects of soil warming, nitrogen fertilization, and plant invasion
Wheeler, J. A., Frey, S. D., and Stinson, K. A. (2017). Tree seedling responses to multiple environmental stresses: Interactive effects of soil warming, nitrogen fertilization, and plant invasion. Forest Ecology and Management 403: 44–51. PDF.
Summary
In addition to the impending rise in global temperatures, scientists have also observed increases in soil nutrients and invasive plant populations throughout New England. However, the combined effects of these stressors on regionally important tree species establishment has yet to be thoroughly investigated. Wheeler et al. (2017) sought to fill this knowledge gap by measuring the compound effects of soil warming, nitrogen addition, and invasion of garlic mustard (Alliaria petiolata), on red maple (Acer rubrum) seedling growth, phenology, survival, and root symbioses. Of the four traits measured, Wheeler et al. (2017) found that red maple seedling growth and beneficial fungal relationships were enhanced by soil warming. Interestingly, these positive effects were offset by interactions between any two of the global change stressors, but not by an interaction between all three stressors. The authors suggest that while soil warming may increase red maple growth initially, plant productivity may suffer from decreased soil water and excess nitrogen in combined treatment applications. Similarly, the benefits of warming appear to be inhibited by the chemical compounds produced by garlic mustard. Given the interactions between the global change impacts observed in this study, Wheeler et al. (2017) encourage forest managers to evaluate the combined effect of both abiotic and biotic interactions in future plans to conserve tree seedlings under predicted climate change scenarios.
Take home points
Soil warming, nitrogen deposition, and impacts of invasive plant species are a threat to native tree seedlings in New England.
The combined effects of soil warming and nitrogen deposition, and soil warming and garlic mustard, have been shown to inhibit the growth and symbioses of red maple seedlings.
Further studies on plant-soil feedbacks will enhance our understanding of interactive effects of global change in New England forests and throughout other regionally important ecosystems.
Management implications
Knowing the projected global change impacts local to your area can help plan for future climate change scenarios since different combinations of stressors have different impacts.
Tree seedlings are particularly vulnerable to increased temperatures and understory invasive plants.
Keywords
Shifting Seasons; Impact Study; Observation; Invasive Plant; Terrestrial Habitat; Alliaria petiolata; Garlic Mustard