Abstract Detail

Ecophysiology

Schneider, Adam [1], Kreiser, Molly [1], Nelson, Gregory [1], Lee, Tali [1].

With changing global precipitation patterns, will the growth of prairie plants be more constrained by reduced rainfall frequency or reduced rainfall volume?

Water deficits are a common limiting factor of plant growth. Many controlled studies have looked at the effects of drought, but few have independently compared the two ways a plant might experience reduced water availability: fewer rain events, or less water per event. Climate change models for North America generally predict similar to increased annual precipitation, but in fewer, more severe events. In this greenhouse experiment, we investigated responses of the legume Lupinus perennis and the grass Agropyron repens to 50% reductions in watering frequency and watering volume. We measured leaf senescence, biomass accumulation, phytosynthetic rates, and for Lupinus, the amount of N derived from N₂ fixation. Responses varied by species, but in general reduced rainfall volume was found to be more limiting than reduced rainfall frequency. Both manipulations increased leaf senescence for Lupinus although the number of leaves produced was unchanged. Biomass accumulation and N₂ fixation rates were significantly reduced in Lupinus grown under decreased volume treatments. However, Agropyron grew similarly across treatments, which may be explained by improved water use efficiency. In the future, predictions of vegetation responses to climate change could be improved by independently considering these two dimensions of water input.

Broader Impacts:

1 - University of Wisconsin-Eau Claire, Biology, Eau Claire, WI, 54702, USA

Keywords:
climate
change
physiology
ecology
Lupinus
Agropyron
precipitation
ecophysiology
greenhouse
Cedar Creek
prairie
grassland.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PEP005
Abstract ID:122
Candidate for Awards:None