2002 ARCSS All-Hands Workshop

Effects of Extended Growing Season on Flower Production of Seven Alaskan Tundra Species at Toolik, Alaska

Tracey A. Baldwin¹, Steven F. Oberbauer^2
1Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA, Phone 305-348-6047, Fax 305-348-1986, tracefsu@aol.com
²Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA

As climate warming occurs in northern latitudes, season length is expected to change. As a result of this change, plant phenology will shift, changing the temporal expression of flowering and other phenological traits with important consequences at the community and ecosystem levels. The purpose of this study was to determine the effect of a shift in growing season on the expression of reproductive phenology in several important tundra plants. We studied the timing of specific phenological events as well as the quantitative production of flowers for 7 species over the course of 2 growing seasons in an arctic tussock tundra community. Flowering abundances and status were measured in an experimental manipulation consisting of increased season length by snow removal coupled with soil warming. There was a strong yearly variation in the quantities of flowers produced, but the number of flowers were not significantly affected by the treatment in either year for any of the species. However, early snow removal slightly accelerated flower development in most species. The dominant plant, Eriophorum vaginatum showed an early progression of flowering status in treatment plots, but control plots fruited at similar times to treatments as a result of accelerated development during flowering. These results indicate that changes in season length may be more important for timing of flowering than for the absolute amount of flowering.

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