Long-term effects of grazing exclusion on aboveground and belowground plant species diversity in a steppe of the Loess Plateau, China

Abstract

International audienceBackground and aims - Livestock grazing exclusion was widely used to manage degraded grassland ecosystems, but little is known on the effects of long-term grazing exclusion on aboveground and belowground species diversity of the steppe vegetation in China. Material and methods - The species composition of the aboveground vegetation and the soil seed bank were examined on sites after a 25-year grazing exclusion in a typical steppe on the Loess Plateau, NW China. Key results - Results showed that long-term grazing exclusion significantly improved vegetation cover, biomass and aboveground species evenness. Long-term grazing exclusion significantly increased species richness and seed density in the soil seed bank, but significantly decreased belowground species evenness. The seeds were mainly present in the litter and the topsoil (0-5 cm), accounting for about 76% of the total seed number. Exclusion of grazing significantly decreased seed depletion in soil seed bank from April to July as compared to grazed sites. The Sørensen similarity index between aboveground and belowground species composition was low in the typical steppe, and long-term grazing exclusion did not significantly improve this similarity. Conclusion - Our results suggest that long-term grazing exclusion can significantly improve both aboveground and belowground species diversity in the steppe vegetation of the Loess Plateau, but has little or no effect on the similarity in composition between the two compartments

Effect of Grazing Exclusion on Vegetation Characteristics and Soil Organic Carbon of Leymus chinensis Grassland in Northern China

“…In this study, we selected the biomass, cover, richness, DS, and SHDI to examine the effect of long-term grazing exclusion on vegetation characteristics. The results indicated that these characteristics increased in the process of restoration, which resulted from an increase in seed germination and seed bank for annual and perennial species when livestock was excluded [27]. We found the mean SOC storage in FG to be 14.12˘0.17 g¨kg´1, which is similar to the average SOC for the steppe in the Xilin River Basin, as reported by Wiesmeier et al [28].…”

“…Grazing exclusion has been reported to be an effective practice to restore degraded grassland, as vegetation characteristics and soil properties have been shown to improve under long-term grazing exclusion [26,27]. In this study, we selected the biomass, cover, richness, DS, and SHDI to examine the effect of long-term grazing exclusion on vegetation characteristics.…”

Effects of grazing exclusion on carbon sequestration and plant diversity in grasslands of China—A meta-analysis

“…For plant diversity, the results are also conflicting. Several studies reported no effects of grazing exclusion on plant diversity (Milchunas and Lauenroth, 1993;Meissner and Facelli, 1999), while a number of studies reported increases (Shaltout et al,1996;Eweg et al, 1998;Shang et al, 2008;Mayer et al, 2009;Jeddi and Chaieb, 2010;Zhao et al, 2011), and others reported decreases (Proulx and Mazumder, 1998;Dullinger et al, 2003;Altesor et al, 2005;Peco et al, 2005Peco et al, , 2006Wu et al, 2009), in plant diversity in response to grazing exclusion. Generally, the effectiveness of grazing exclusion denpends on its duration (Milchunas and Lauenroth, 1993;Su et al, 2005;Wu et al, 2008;McSherry and Ritchie, 2013), environmental conditions (Conant and Paustian, 2002;Derner and Schuman, 2007;Piñeiro et al, 2010; J.S.…”

Soil Seed Bank and Plant Community Development in Passive Restoration of Degraded Sandy Grasslands

“…Desertification of sandy areas in Northeast China, which is primarily triggered by overgrazing [1,2], poses a serious threat to ecosystem structure and function, resulting in reduced productivity [3]. Restoration methods such as passive restoration (i.e., removing domestic grazers) and active restoration (i.e., replanting target plant) have been widely used in degraded sandy grasslands [4][5][6][7].…”

“…In addition, passive restoration methods are as effective as active restoration [11,12]. Thus, passive restoration has mostly been employed in degraded sandy grasslands of semi-arid regions [1,2,13].…”