Warming, Soil Moisture, and Loss of Snow Increase Bromus tectorum’s Population Growth Rate

Authors

Aldo Compagnoni, Utah State University
Peter B. Adler, Utah State UniversityFollow

Document Type

Article

Journal/Book Title/Conference

Elementa: Science of the Anthropocene

Publication Date

1-8-2014

Volume

2:20

Publisher

University of California Press * Journals Division

Abstract

Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum) is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1) warming increases cheatgrass population growth rate and 2) reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.

Comments

Plant demographic data: Data available from the Dryad Digital Repository: http://doi.org/10.5061/dryad.63872.

First Page

1

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Last Page

10

Recommended Citation

Aldo Compagnoni, Peter B. Adler; Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate. Elementa: Science of the Anthropocene 1 January 2014; 2 000020. doi: https://doi.org/10.12952/journal.elementa.000020