Soil and spatial dependence of landscape dynamics in Chihuahuan Desert grasslands

TitleSoil and spatial dependence of landscape dynamics in Chihuahuan Desert grasslands
Publication TypeConference Paper
Year of Publication2002
AuthorsBestelmeyer BT, Gile L.H, Nolen B., H. Monger C, Havstad K
Conference Name17th Annual Symposium, US-International Association for Landscape Ecology
Date PublishedApril 23-26, 200
Conference LocationLincoln, NE
ARIS Log Number142716
AbstractIt is clear that soil properties, landscape position, and nutrient transfers among landscape elements affect the properties of plant communities. Nonetheless, few studies have attempted to account for these variables in explaining plant community dynamics. We examine how changes in grass cover, grass patch structure, and shrub abundance varied on different soils within the southern Jornada del Muerto Basin of New Mexico, USA. Changes in vegetation patterns revealed by repeat photography over 30-40 years (from 1959-2001) were related to detailed measurements of soil properties and geomorphology taken at each photography site as part of the Desert Soil-Geomorphology Project of the Natural Resources Conservation Service. On heavy soils on basin floor or lower piedmont positions, grass patch structure was remarkably stable or patch size increased over the study period. Shrub abundance increased little or even declined. On loamy to sandy soils on upper piedmont positions that were not already devoid of grass, grass cover has declined and shrub abundance and size increased. It is likely that the translocation of water and other resources from degrading sites on upper fan piedmont positions lead to the stability or increases in grass cover observed in downslope landscape positions. These patterns indicate that interpretations of rangeland degradation must account for soils, geomorphology and landscape connectivity.