Changes in Richness and Species Composition after Five Years of Grazing Exclusion in an Endemic Pasture of Northern Mexico

Abstract

A well-managed grazing system improves the productivity and health, and it is important to promote sustainability. We analyzed the impact of grazing on the Sierra de Zapalinamé protected area in north Mexico. Our hypothesis was that grazing modifies species composition, richness, and nutrients after grazing exclusion for five years. In this area, eight plots were excluded from grazing, and species richness, evenness, and plant functional types for five years were monitored. This monitoring was also carried out on eight control plots adjacent to the excluded plots. Soil samples were collected from each plot in the fifth year of exclusion for nutrient content analysis. Grazing discriminated plant species composition after five years between excluded and control plots, but not species richness and evenness. In addition, exclusion increased grass cover and decreased forb cover. Indicator species for excluded and control sites were identified. It was concluded that part of the pastures can be excluded from grazing as a way to analyze changes in this protected area and promote greater plant diversity.

Effects of Scale, Temporal Variation and Grazing on Diversity in an Endemic Pasture in Sierra de Zapaliname, Coahuila, Mexico

“…The study examined the effects of five years of cattle grazing exclusion in a native pasture in northern Mexico. Previous studies on this site [39] revealed no significant differences in species richness, evenness, and soil nutrients between the grazed and ungrazed areas. However, some species showed a higher prevalence in the ungrazed compared to the grazed plots.…”

“…Consequently, higher z values emphasize the significance of landscape heterogeneity in fostering species coexistence and accentuate the need to consider both area and habitat diversity in conservation and management strategies. In previous studies on this site, general richness analyses revealed non-significant differences [39], so the consideration of the scale should be incorporated in the analyses to detect the impact of management on the plots [41].…”