PARENT SESSION
Organized Oral Session 4: Importance of the Abiotic Environment for the Ecology and Evolution of Flowers
Organized by: T Ashman and A Case
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 104.
Modification of plant-pollinator interactions through consequences of global and regional climate changes.
Inouye, David1, 2, 1 University of Maryland, College Park, MD, USA2 Rocky Mtn. Biological Laboratory, Crested Butte, CO, USA
ABSTRACT- A 30-year study of the timing and abundance of flowering at 2,900m in the Colorado Rocky Mountains shows that there is great variation in both of these aspects of flowering, and that much of it can be explained by abiotic factors. Timing of flowering for all species studied to date is explained by the timing of snowmelt in the spring, which is largely a function of how much snow fell the previous winter. For several species the abundance of flowering is strongly correlated with depth of winter snowpack, either through some mechanism yet to be discovered, or in some cases mediated by the interaction between time of snowmelt and probability of late spring frost damage to flower buds. Sometimes most flower buds of some species are killed by frost, with consequences for flower visitors, herbivores, seed predators, and their parasitoids. Variation in snowpack and snowmelt in this part of the Rockies is influenced strongly by global factors such as climate warming and regional influences such as the El Niño-Southern Oscillation and the recently discovered North Pacific Oscillation. The NPO has about a 50-yr cycle, and much of the study presented here was encompassed by the last wet phase (starting in 1977). A 1998 phase change of the NPO appears to have triggered an abrupt decline in winter precipitation, with effects (primarily negative) on flowering by many species. Winters since 1998 have had declining snowfall, which has resulted in reduced flowering by many species (through a combination of frost damage and unknown mechanisms). Climate change is also changing the synchrony of plants and pollinators, as the plants and animals at this site are apparently responding to different environmental cues or respond differently to the same cues.
Key words: climate change, frost, flowering, phenology