|JOHNSON, A - CLEMSON UNIVERSITY
|TURNER, S - ST. CLOUD STATE UNIV
|WHITFORD, WALTER - NEW MEXIC0 STATE UNIV
|DE SOYZA, A - TERRESTRIAL ENV RES CTR
|Van Zee, Justin
Submitted to: Journal of Arid Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/16/1999
Publication Date: 3/1/2000
Citation: Johnson, A.R., Turner, S.J., Whitford, W.G., de Soyza, A.G., Van Zee, J.W. Multivariate characterization of perennial vegetation in the northern Chihuahuan Desert. Journal of Arid Environments. 2000. v. 44(3). p. 305-325.
Interpretive Summary: The northern Chihuahuan Desert in south-central New Mexico has been subject to considerable ecological changes in the past century. The purpose of this study was to document the current shrub dominance and remnant grassland of this region. Vegetation data were collected at 100 study sites. Study sites were selected as part of an effort to accurately assess satellite imagery of the area. The most frequently encountered species in this study was the subshrub broom snakeweed. Creosotebush and honey mesquite were the most common shrubs encountered and contributed the highest to perennial cover. Only a small number of sites surveyed were considered to be grass-dominated sites. These results indicate that the shrubs creosotebush and honey mesquite are now the definitive elements of the regional vegetation. This study also suggests that encroachment of shrubs into grasslands is higher in the southern portion of the study area. The analysis presented here serves as a snapshot of current vegetation in the northern Chihuahuan Desert and provides a benchmark for monitoring future vegetation change in the region.
Technical Abstract: We surveyed vegetation at 100 sites in southern New Mexico to establish a benchmark for monitoring vegetation change. Sites were selected in a stratified random design based on a classified AVHRR image. Two shrubs (Larrea tridentata and Prosopis glandulosa) are the most important contributors to perennial cover in the area. Principal components analysis (PCA) and detrended correspondence analysis (DCA) both clearly delineate these shrublands from the smaller number of compositionally varied grassland sites. A latitudinal trend in DCA axis 1 scores suggests that encroachment of shrubs into grasslands is most pronounced in the southern portion of the study area.