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

Abstract

Grasslands and pastures are extensively studied due to their geographic variation, species richness, ecological functioning, and economic importance. They are vital components of land use in many parts of the world. The impact of grassland management on species diversity and species composition has also been widely discussed, but results have been contradictory. It is well known that the relationship between species richness and the sampled area is perhaps one of the most consistent rules in plant ecology. This relationship is particularly important in biodiversity studies as it helps to predict richness at larger scales. Additionally, species richness is also influenced by absolute plant abundance, spatial patterns, and the degree of species mixing. However, species richness also depends on absolute plant abundance, spatial patterns, and the degree of mixing species. To assess this relationship, we analyzed the impact of cattle grazing on species richness at a sampling scale in the Sierra of Zapaliname, a protected area in northern Mexico. Our results revealed that the increase in plant species concerning the sampling area significantly differed in the plots excluded from grazing from the control (grazed) plots, and these relationships are differently detected in the function of the scale. Despite the lack of differences in previous studies on species richness without considering the scale, once the scale is incorporated, differences arise among both treatments. As indicated in previous studies, grazing exclusion can lead to a decrease in species richness, but we suggest that some areas of the pasture could be excluded from grazing for longer periods, as long as it is compatible with the economic needs of the local inhabitants, to investigate changes and promote diversity, especially for plant species associated with areas excluded from grazing.