Plant species associations with different patch types at a semiarid-arid grassland ECOTONE

Title	Plant species associations with different patch types at a semiarid-arid grassland ECOTONE
Publication Type	Conference Paper
Year of Publication	1999
Authors	Kroel-Dulay G., Odor P., Peters DC
Conference Name	5<sup>th</sup> World Congress, International Association for Landscape Ecology
Date Published	July 29-August 3
Conference Location	Snowmass Village, Colorado
ARIS Log Number	100570
Abstract	The objective of this study was to investigate the relationship between subordinate species and the mosaic of dominant grasses at a semiarid-arid grassland ecotone and to compare these localized patterns of species to their geographic range. In central New Mexico, USA, a biome transition zone occurs where Bouteloua gracilis, the dominant of the shortgrass steppe, and Bouteloua eriopoda, the dominant in Chihuahuan Desert grasslands dominate. We used a multiple scale (0.25-256 m²) design to sample species occurrence in 60 patches dominated by either of these two grasses (30+30). Patches of the two types were interspersed across the landscape within a 1500ha area. Soil samples (0-20cm) were collected to test the hypothesis that soil texture controls the distribution of the dominant grasses. Patches dominated by B. gracilis had soils with significantly higher clay content relative to the other patch type. Of the 44 species with sufficient frequency for statistical analyses, 15 were associated with B. gracilis dominated patches, and 10 with B. eriopoda dominated ones. These two sets of species did not clearly differ in their geographic distributions. Our results indicate that this transitional mosaic is composed of patches with different species composition but it is not a mosaic of the interacting biomes.