Document: DAV-3-34-78
Reproductive response of Delphinium nelsonii (Ranunculaceae) to a subalpine climate warming experiment .
SAAVEDRA, F.* 1,2 and D.W.INOUYE 1,2
University of Maryland, College Park MD 20742, USA 1
Rocky Mountain Biological Laboratory, Crested Butte CO 81224 USA 2
Abstract:
High altitude and high latitude sites are expected to be very sensitive to global warming. Long term studies in a subalpine meadow of the Colorado Rocky Mountains showed a strong correlation between snow pack and Delphinium nelsonii flower production, and predicted that global warming might have a negative fitness effect on D. nelsonii and other early flowering species. In this article we report an experimental study of the effects of global warming on the density and flower production of Delphinium nelsonii. We found that experimental warming has a negative effect on D. nelsonii flower production, supporting earlier predictions. D. nelsonii plants responded to the warming through a reduced density of flowering plants and by having fewer flowers per plant in the heated plots compared to the controls. Flower bud abortion was higher in the heated plots than the natural controls only in 1994, a year with especially low snow accumulation. These results contrast with others for the same species in a snow removal experiment. Snow removal did not consistently affect D. nelsonii fitness (e.g., flower number per plant), suggesting that other factors than snow cover, such as temperature or soil moisture, are likely to be more important in modulating the response of D. nelsonii to snow pack. Our results suggest that global warming may affect the abundance of D. nelsonii and similar early flowering species in high altitude sites, affecting pollinators and plants that depend on them.
Keywords: climate change; experimental warming; alpine; fitness; plant density; flower production; flower abortion; Colorado; long-term study; Delphinium nelsonii; larkspur.
This abstract is being presented at: 10:45 AM in session:
Oral Session #43: Plant Community Responses to Climate Change.