PARENT SESSION
Poster Session # 21: Biogeography, Biodiversity, Populations, and Genetics.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Spatial scaling of plant species richness in grasslands: relationships to productivity, soils and management.
Murphy, C.*,1, Foster, B.1, Ramspott, M.1, Price, K.1, Hildebrand, T.1, Evanhoe, L.1, 1 University of Kansas, Lawrence, Kansas
ABSTRACT- Management regimes of varying types and intensities can have profound impacts on grassland biodiversity at various spatial scales. We examined plant species richness in relation to productivity and soil characteristics at several spatial scales in grasslands of Northeastern Kansas. Plant species richness, biomass, soil bulk density, soil carbon and nitrogen were measured in four managed grassland regimes (cool season hay and grazed, warm season hay and grazed). In 2001, data were collected within fifty-four, 1m2 quadrats placed systematically within an area of 14,400m2 in each of nine fields. The program, EstimateS, was used to generate species accumulation curves for each field and estimates of species richness at different spatial scales (1-54m2). Among fields, a unimodal, quadratic relationship was found between species richness and biomass at all spatial scales. Species richness was negatively correlated with soil bulk density, but positively correlated with soil carbon and nitrogen. The variance in richness explained by soil variables, and the slopes of these relationships, increased with spatial scale, reflecting large differences in spatial heterogeneity among fields of contrasting management. The observed relationships of plant species richness to productivity and soils reflect a complex gradient of human-induced disturbance associated with current and historic agricultural land-use.
Key words: productivity, spatial scale, biodiversity, prairie