Figure 1.
Location of prairies sampled across a significant precipitation gradient in the Great Plains.
Prairie locations are (1) Smoky Valley Ranch, (2) Wilson Lake, (3) The Land Institute, (4) Konza Prairie Biological Station, and (5) Tucker Prairie. The background shading indicates an interpolation of annual average precipitation (cm) from 1961–1990 (where the precipitation map is copyright PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu).
Figure 2.
Collection sites for Andropogon gerardii.
Figure 3.
Sampling methodology at different scales.
Each prairie (A) contained four transects. Each 40 m transect (B) contained a series of five subgroups. Five ramets were sampled at each subgroup (C).
Table 1.
Tallgrass prairies sampled, with state, UTM coordinates, AFLP sample size, Rxo1-RFLP sample size and average annual precipitation from the nearest weather station (1971–2000).
Figure 4.
AFLP dissimilarity by geographic distance.
Points from left to right are plotted at 1.8 m (within subgroup), 10 m (between adjacent subgroups), 20 m, 30 m, 40 m, 2139 m (between transects), and 473,025 m (between prairies). The slope parameter (‘b’), and 95% confidence interval from a randomization test are indicated.
Figure 5.
AFLP (a) and Rxo1 (b) dissimilarity across precipitation.
The mean dissimilarity for each prairie was calculated and plotted according to average annual precipitation. The p-value (‘p’), slope parameter (‘b’) and standard error (‘se’) from a linear regression model are indicated.
Figure 6.
Shannon's information measure (H′) calculated for AFLP (a) and Rxo1 (b) results for each prairie as a function of average annual precipitation.
The p-value (‘p’), slope parameter (‘b’) and standard error (‘se’) from a linear regression model are indicated.