Low sagebrush responses to passive warming and snowpack removal
In western North America, climate change is predicted to result in a 2-5º C warming by 2050, with declines in snowpack. Those possible changes may strongly influence the physiology of vegetation, especially in high-elevation communities that are sensitive to changes in environmental conditions. To better predict plant responses to future changes in climate, we used an ongoing climate-change experiment in a montane meadow of Grand Teton National Park. We investigated the effects of warming (1-3º C) and decreased spring snowpack (~15%) on the physiology of low sagebrush (Artemisia arbuscula). We specifically measured leaf-level gas exchange, plot-level plant cover, intrinsic water-use efficiency with stable carbon isotopes, and hydraulic vulnerability.
Preliminary results indicated that photosynthetic carbon gain, respiration, and stomatal conductance were not significantly affected by either warming or snowpack removal. Plant water-status (water potentials) was significantly improved by warming, but was not affected by snowpack manipulations. Overall plant-cover was a significantly increased by snowpack removal and warming. Intrinsic water-use efficiency was not significantly affected by treatments, but show slight differences in water-use between treatments. Hydraulic vulnerability curves indicate that shrubs in warmed and snow removal plots had a lower P50. Collectively, our data demonstrate that photosynthetic carbon gain A. arbuscula may not be sensitive to slight changes in temperature or winter precipitation. However, plant water-relations may be responsive to slight changes in temperature and snowpack removal. Our findings suggest minimal changes in low sagebrush’s ecophysiological performance in response to warming and altered precipitation, which may help explain why it had relatively large changes in growth in a related study.