Biology ETDs

Publication Date



The Sevilleta Wildlife Refuge and Ladron Mountains of westcentral New Mexico were selected for a floristic inventory and analysis because of a lack of previous study in this unique area. A key and annotated checklist of the vascular flora of the study area were compiled. The 1140 taxa representing this floristically diverse area were documented by either (i) specimens in the University of New Mexico Herbarium or (ii) specimens collected during 1975 and 1976. Twelve floristic communities are recognized. These are based upon descriptive field notes, species lists from collection sites, and photographs taken during collection trips. The communities are the Rio Grande floodplain, Rio Salado sand-dune, grassland riparian, montane riparian, desert grassland, grassland wash and arroyo, desert shrubland, interior chaparral, montane canyon, evergreen woodland, forest, and rock-shield and talus-slope. Community integrity and floristic affinity analyses are based on three types of data for each community: (i) the affinities and composition of the dominant taxa, (ii) taxa that appear to be restricted to individual communities, and (iii) taxa that end their geographic distribution within the study area. The community integrity analysis reveals a striking difference between the communities associated with the Rio Grande valley and those associated with the Ladron Mountains. Approximately 17% of the total species of the desert grassland and adjacent communities are restricted to these communities, while the communities associated with the Ladron Mountains have nearly 25% of the flora restricted to these communities. The desert grassland community shares a greater number of species with the adjacent communities than does any other community, while the montane riparian community shares the least number of species with the adjacent communities. The desert grassland and interior chaparral communities contain the greatest number of taxa with southern affinities ending their distribution on the refuge, and the evergreen woodland community contains the greatest number of species endemic to central New Mexico. The floristic affinity analysis indicates that the total flora of the study area has a strong affinity with the flora of southern New Mexico. However, the montane riparian community seems to have a greater affinity to the Rocky Mountain influence, while both the rock-shield and talus-slope community and the forest community seem to have strong affinities with the Mogollon influence of southwestern New Mexico. This analysis has also shown that the study area is located at the convergence of a number of the major floristic influences within New Mexico and the plants of the study area may be undergoing rapid species evolution.



Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

William Clarence Martin

Second Committee Member

William George Degenhardt

Third Committee Member

Clarence Clayton Hoff

Included in

Biology Commons