Impact of 25 years of grazing exclusion and shrub removal on plant community structure and soil characteristics in a xerophytic rangeland

Jose R Arévalo,Juan A Encina-Domínguez,Miguel Mellado,Eliseo Suárez-Hernández,José Dueñez,José E García

doi:10.5424/sjar/2020181-15934

Abstract

Aim of study: We tested the hypothesis that long periods of grazing exclusion in areas with a history of high grazing intensity will have a positive impact on soil nutrient conditions and favor soil infiltration, increase biomass and lead to a recovery in vegetation.Area of study: Noria de Guadalupe, Zacatecas, Mexico.Material and methods: We analyzed the impact of grazing exclusion on biomass, species richness, evenness, soil nutrient content and soil water infiltration after 25 years of exclusion during each of the four seasons by excluding two 15 × 15 m plots of grazing and compared with two control plots.Main results: Exclusion management did not lead to biomass increases; however, it did lead to an important recovery in the plant community. Moreover, soil nutrient content was more affected by the seasonality of rainfall in the study site than by 25 years of exclusion. The elimination of dominant shrubs in the excluded area led to a faster recovery in palatable shrubs and shortgrass vegetation, which was improved by better infiltration values during the end of spring and summer explaining some of the differences in nutrient avaibility.Research highlights: In our study, exclusion management can lead to an important recovery in vegetation without affecting the growth of Atriplex canescens, a valuable source of fodder. Although biomass presented a higher dependence on seasonality and was not related to the treatment, the impact on the forage quality is evident by the different plant communities established after 25 years of exclusion.

Highlights

An ecological force such as grazing with important environmental and social implications must be analyzed thoroughly to propose sustainable practices (Arévalo, 2012)
Research highlights: In our study, exclusion management can lead to an important recovery in vegetation without affecting the growth of Atriplex canescens, a valuable source of fodder
Two species were only found in the grazed plots: Koeberlinia spinosa Zucc. and Cylindropuntia leptocaulis (DC.) F.M

Summary

Introduction

An ecological force such as grazing with important environmental and social implications must be analyzed thoroughly to propose sustainable practices (Arévalo, 2012). Grazing management is one of the most important traditional and sustainable land uses in many areas of the world (Milchunas et al, 1988; Crawley, 1997). Grazing lands require appropriate techniques to maintain species composition, soil conservation and high diversity values of plant communities (Baldock et al., 1994; Olff & Ritchie, 1998; Teague & Barnes, 2017). Mismanagement can cause marked and significant variation in species composition Encina-Domínguez, José Dueñez and Eliseo Suárez-Hernández et al, 2004; Arévalo et al, 2007). Overgrazing is a common occurrence in many rangelands, increasing the risks of erosion and desertification and promoting exotic species

Methods

Results

Conclusion