Abstract Detail

Ecophysiology

Khorsand Rosa, Roxaneh [1], Oberbauer, Steven [1], Starr, Gregory [2], Pop, Eric [3], Ahlquist, Lorraine [4], La Puma, Inga P. [5], Baldwin, Tracey [6].

Predicting phenological responses of arctic tundra species to climate change.

The phenological responses of arctic tundra plants to warming temperatures as a result of climate change will have important consequences for species composition and diversity. These responses will, in turn, influence ecosystem interactions and processes. Thus, predicting plant responses to changes in temperature and duration of growing season is critical to carrying out effective conservation strategies in the arctic. We studied the effects of soil warming and lengthened growing season (early snow removal) on eight tundra species at Toolik Lake, Alaska, between 1995 and 2003. We asked two questions: 1) How does treatment affect the timing of leaf bud break, leaf senescence, and flowering? and 2) Are treatment responses species-specific? The species studied included two graminoids: Carex bigellowii and Eriophorum vaginatum; three evergreen shrubs: Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea; two deciduous shrubs: Betula nana and Salix pulchra; and one forb: Polygonum bistorta. From May through August, we conducted weekly observations to record leaf and flowering phenology in a total of eighteen plots: control (n = 6), soil warming, and snow removal + soil warming. In all species except Cassiope tetragona, leaf bud break and senescence, as well as flowering, began significantly earlier in the experimental plots than the control plots. Duration of leaf growth and flowering, however, did not differ among treatments.  These results suggest that arctic species will adapt to climate warming by beginning vegetative and reproductive processes earlier than under non-warming conditions, although the total duration of these processes may not change significantly. However, initiating growth and flowering may have detrimental effects when freezing does occur. Therefore, we can possibly expect to see an increase in abundance of aperiodic species whose growing period is controlled by external factors and a decrease in periodic species (such as C. tetragona) whose growing period is genetically fixed.

1 - Florida International University, Biological Sciences, 11200 SW 8th St., Miami , FL, 33199, USA
2 - University of Alabama, 1325 Science and Engineering Complex, Box 870344, Tuscaloosa, AL, 35487, USA
3 - Bay Area Air Quality Management District, 939 Ellis St. , San Francisco, CA, 94109, USA
4 - Parsons Brinckerhoff, 401 B Street, Suite 1650, San Diego, CA, 92101, USA
5 - University of Wisconsin, 1630 Linden Dr, Madison, WI, 53706, United States
6 - National Ecological Observatory Network, 1685 38th St., Ste. 100, Boulder, CO, 80301, USA

Keywords:
phenology
Arctic
Tussock tundra
Flowering
Climate change
Growing season.

Presentation Type: Oral Paper:Papers for Topics
Session: 15
Location: Firs South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 9:15 AM
Number: 15006
Abstract ID:437
Candidate for Awards:None