Revista Chilena de Historia Natural 83 (3): 395-407, 2010
RESEARCH ARTICLE
Abiotic gradients drive floristic composition and structure of plant communities in the Monte
Desert
Defining plant communities in desert zones is difficult due to large scale homogeneity and
small scale heterogeneity, thus making provision of systematic information for conservation decisions problematic. We analysed plant
communities of the most arid sector of Monte Desert for structure, plant composition and environmental variables. Small-scale
variables such as slope, rock cover, bare ground and litter, as well as large-scale ones such as species diversity, composition and
similarity within and between sites were included. Analyses of floristic composition showed the difficulty of segregating distinct
communities due to high internal heterogeneity and overlap between the different sites. Only mesquite woodlands, a community
situated at the extreme of the soil moisture gradient was segregated. Ordination on structural variables was somewhat more
successful in segregating communities on the basis of substrate type and of tree and shrub cover. Our results showed the difficulty
distinguishing plant communities in temperate deserts, suggesting the existence of relatively stable assemblages of species at the
extremes of the gradients and of great heterogeneity within and between sites. They cannot be defined by floristic variables solely, but
require environmental information also.
Key words:
arid environment,
heterogeneity, shrubland, similarity, species richness
