Abiotic gradients drive floristic composition and structure of plant communities in the Monte Desert

Abstract

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 largescale 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.

Measuring ungulate tolerance to human with flight distance: a reliable visitor management tool?

“…The predominant vegetation is sparse shrubland (less than 20% of plant cover), dominated by species of Zygophyllaceae (Larrea spp., Zuccagnia punctata), Fabaceae (Prosopis spp., Cercidium praecox, Geoffroea decorticans) and Chenopodiacae (Atriplex spp. and Suaeda divaricata) (Acebes et al 2010b).…”

Effects of bark damage by feral herbivores on columnar cactus Echinopsis (=Trichocereus) terscheckii reproductive output

“…In this habitat, shrub cover is approximately 20% of ground area. The most frequent species are Larrea cuneifolia, Zuccagnia punctata, Deuterocohnia longipetala, and several cacti such us Opuntia sulphurea, Denmoza rhodacantha and Echinopsis (¼Trichocereus) strigosus (Acebes et al, 2010;Márquez et al, 2005).…”

Lack of feral livestock interference with native guanaco during the dry season in a South American desert

“…Habitats identified in IPP were: mesquite woods, a community associated with seasonal rivers, dominated by Prosopis chilensis; creosote mixed scrub, associations of Larrea cuneifolia, Z. punctata and other woody species, with low and sparse plant cover (5-10%); columnar cactus slopes, formations physiognomically dominated by columnar cacti (Trichocereus terscheckii) and other small cacti, accompanied by underbrush; barrens, areas with practically bare soil, where plant cover varies between 0% and 5%; saltbush, communities dominated by Atriplex lampa and/ or Atriplex spegazzinii (5-10% of plant cover); and sand dunes, communities dominated by grasses (Stipa spp.) on sands with low plant cover (for a detailed description of these habitats, see Márquez et al 2005;Acebes et al 2010a). Habitats selected in TNP were: retamal, monospecific formations of B. retama and hillocks, rock formations with little plant cover including some species of the Zygophyllaceae family (Larrea spp, Z. punctata, B. retama and P. tetracantha).…”

“…and Opuntia sulphurea) and Bromeliaceae (Deuterocohnia longipetala and Tillandsia spp.) (Acebes et al 2010a).…”