Slope and Aspect Influences on Plant Distribution

in a Semi-Arid Region of Central New Mexico

Dello Russo, Regina E. and J.B.J. Harrison, University of New Mexico, Albuquerque, New Mexico 87131, USA, and New Mexico Tech, Socorro, New Mexico 87801, USA

1995 Annual Meeting

Ecological Society of America

The availability of water is usually considered to be the main factor influencing the distribution of plant communities in semi-arid environments. On sloping terrain in such environments rainfall-runoff processes result in significant changes in soil moisture over short distances. However, because the soil moisture also affects soil development processes, there may be concomitant changes in soil fertility along a slope. We studied the distribution of plant communities and soil properties along two slopes of different aspect from a small first order drainage basin in the Sevilleta National Wildlife Refuge in central New Mexico. Significant differences in the distribution of plant species was found along a slope and on the different aspects. Soil development also varied according to slope position. We are continuing the study to determine how much of the variation in the distribution of plant species can be explained by soil moisture variation and how much is due to changes in soil fertility.