Document: MAN-3-34-64

The effect of snowpack on the timing and abundance of flowering in the montane plant, Delphinium barbeyi.

MORALES, M.A.* and D.W.INOUYE

University of Maryland, College Park, MD 20742, USA ¹

Abstract:
Many montane species are insulated from the damaging effects of frost by snowpack. For these species, predicted changes in precipitation associated with global climate change may have a significant impact on populations in ways unrelated to temperature. Of special interest are plants that flower at the beginning of the growing season, because these species are especially susceptible to frost damage, but may also help attract and support pollinators that then service later-flowering plants. Generally, global climate change may have a disproportionate effect on montane communities, because species in these habitats may not be able to respond to change in temperature with a shift in latitudinal range, and because area decreases as altitude increases. Unfortunately, the response of many species to variation in climate remains largely unpredictable. One approach is to correlate population level response of organisms to annual variation in environmental conditions. Previous studies have detected a link between variation in snowpack and the timing and abundance of flowering during the subsequent summer for the early-flowering montane plant Delphinium nelsonii (Ranunculaceae). We used a long-term data set collected at the same site (Rocky Mountain Biological Laboratory, 2800 m) to study variation in the timing and abundance of flowering for the long-lived perennial species Delphinium barbeyi, which flowers in mid-season, over the period from 1975 to 1999. Results show that snowpack is positively correlated with both the density of stems and the timing of flowering. Similarly, timing of flowering and stem density are positively correlated with flower abundance. In contrast, snowpack alone explains none of the residual variance in flower abundance. These results suggest that snowpack influences flowering in D. barbeyi by two different mechanisms. In the first, snowpack increases the density of stems. In the second, snowpack delays the timing of flowering, and therefore protects flowers from the damaging effects of early season frosts. These results suggest that changes in precipitation associated with global climate change may have a significant impact on populations of this species.

Keywords: climate change; Delphinium barbeyi; flowering; frost damage; phenology; reproductive biology; snowpack

This abstract is being presented at: 10:30 AM in session:
Oral Session #43: Plant Community Responses to Climate Change.