Poster Session #31: Climate Change.
Wednesday, August 8, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall


Influence of climate on plant and soil microbial diversity of a shrub-steppe ecosystem.

Bolton, Harvey1, Smith, Jeffrey2, Bailey, Vanessa1, Link, Steven3, 1 2 3

ABSTRACT- Global climate change (e.g., temperature and precipitation) may impact the amount and diversity of the plant and soil microbial biomass. Plant diversity, cover, and soil microbial biomass are essential for ecosystem structure and function. Study areas were established in a shrub-steppe ecosystem at 310, 591, 743, 840 m elevation, which provided a natural gradient of decreasing temperature and increasing precipitation as elevation increased. Soil was sampled underneath Pseudoroegneria spicata (bluebunch wheatgrass) a dominant plant at the four sites and cryptogamic soil lichen crust. Percent plant cover decreased with decreasing elevation. Although the total number of plant species did not vary significantly at the four sites, the species composition did. Soil microbial biomass C and N were significantly higher under P. spicata than crust and tended to decrease with decreasing elevation. The culturable microorganisms were more diverse under P. spicata as determined by colony type and diversity decreased as elevation decreased. These results suggest that as climate becomes warmer and drier, percent plant cover will decrease and biomass and diversity of soils microorganisms will decrease.

KEY WORDS: Biodiversity, climate change, soil microorganisms, shrub-steppe