PARENT SESSION
Monday, August 7, 5:00-6:30 pm
Poster Session 7 - Climate and global change
Exhibit Hall, Ballroom Level, Cook Convention Center
The effects of supplemental warming and precipitation on growth and reproduction of Antarctic vascular plants.
Ruhland, Christopher *,1, Strauss, Sarah2, Krna , Matthew 1, Day , Thomas 2, 1 Minnesota State University, Mankato, MN2 Arizona State University, Tempe, AZ
ABSTRACT- Mean annual air temperatures along the west coast of the Antarctic Peninsula have increased >2.9oC over the past 50 years. In addition, many regional-climate models predict that precipitation will change as well. We examined how warming and increased precipitation alters growth and reproduction of Antarctic vascular plants. We placed intact cores of vegetation containing the two native vascular plant species (Deschampsia antarctica and Colobanthus quitensis) under heaters that supplied an additional 28 W m-2 of infrared radiation or under dummy heaters. We also supplemented half the cores weekly with an additional 25% of ambient precipitation. Canopy air and soil temperatures of cores under heaters averaged 1 and 2oC higher than those under dummy heaters. We conducted 10-d non-destructive growth and reproduction measurements over the course of two growing seasons. Warming lead to a 43 and 300% increase in leaf and tiller production in D. antarctica and a 19 and 20% increase in leaf and branch production in C. quitensis. Warming also dramatically accelerated reproductive development of both species. The percentage of D. antarctica panicles reaching maturity at seasons end increased from <8 to 25-35% under warming. The percentage of C. quitensis capsules reaching maturity increased from <1 to >20-32% with warming. There was a species-dependent warming interaction with precipitation: Additional precipitation further enhanced warming effects in D. antarctica, but reduced them in C. quitensis. This is consistent with their microsite preferences along the Peninsula, and suggests that changes in future warming-precipitation regimes could alter recruitment and species composition with future climate change.
Key words: tundra, plant growth, climate change