Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Mountain grassland are an essential component of pasture resources in the Xinjiang UygurAutonomous Region. However, mountain grassland are highly vulnerable to human-associated disturbance andclimate change. The responses of the mountain grassland plant community characteristics and diversity todifferent grazing managements in Barkol County, Xinjiang, are still unclear. In this study, three different grazingmanagement treatments were set up in 2012 to investigate the response patterns of the plant communitycharacteristics, diversity, and the relationship between the diversity and the aboveground biomass in the mountaingrasslands. The three grazing management blocks were M0, M1, and M2, which represented the permanentgrazing prohibition, winter grazing, and year-round grazing management, respectively. During the peak growingseasons of 2013, 2017, and 2022, the data regarding the number of species, height, coverage, density, andaboveground plant biomass were collected for further analysis. The results indicated that the different grazingmanagements had no significant impacts on the importance value of the dominant species, such as Stipa glareosa.However, the importance values of the nondominant species such as Neotrinia splendens and Achnatheruminebrians (Hance) Keng increased under winter and year- round grazing. As grazing intensity increased, plantheight, coverage, density, aboveground biomass, and their response ratios declined significantly (P<0.05). Therewere no significant differences in the Shannon- Wiener diversity, Simpson dominance, and Pielou evennessindices in M0, M1, and M2. In contrast, the Margalef richness index elevated markedly (P<0.05), indicating thatgrazing provided more survival resources helpful for other species. In the permanent grazing prohibition block,the aboveground biomass was negatively correlated with the Simpson dominance, Shannon-Wiener diversity, andPielou evenness indices. In the winter grazing block, aboveground biomass was negatively correlated with theMargalef richness index. Overall, the importance value of the dominant species showed no remarkabledifferences under varying grazing management, and its dominance remained unchanged. Except for the Margalefrichness index, the other diversity indices were not significantly influenced by grazing. Winter and year- roundgrazing enhanced the vital value of unpalatable species, altering the composition of forage, which was notconducive to future animal husbandry development. In summary, as the enclosure time increased, permanentgrazing prohibition was beneficial for restoring degraded grasslands, improving community characteristic values,improving grassland productivity, and maintaining community stability to a certain extent. Grazing would affectresource redistribution in the ecosystem, releasing ecological niches for more species, but year-round grazing ledto intensified grassland degradation because of overgrazing pressure.
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract： 草本层是古尔班通古特沙漠植被的重要组成部分，在维持沙漠稳定、养分循环等方面具有重要意义。水分通常以积雪和降雨形式输入到土壤，输入方式及数量变化对荒漠植物的存活和生长有重要影响。本文以古尔班通古特沙漠南缘草本层为研究对象，利用人工增减积雪的方法，共设置4个积雪处理(0，50%，100%，200%积雪，其中100%积雪为对照)，于2009—2016年春季调查草本植物的数量特征和物种丰富度，分析草本植物数量特征对水分变化的响应；同时结合气象数据，分析不同年份一年生荒漠草本植物数量特征与主要气象因子的关系。结果表明：表层土壤含水量与积雪厚度成正比，相应的草本植物的幼苗密度与积雪水当量、表层土壤含水量成正比关系；2009—2016年，年内积雪量的变化对物种丰富度没有显著影响，各积雪处理间物种丰富度差异不显著；2009—2016年自然处理下年际间物种丰富度差异显著，2015年物种丰富度显著小于其余年份。结合气象数据分析发现，物种丰富度年际变化主要受幼苗建成期的降雨调控，并且干旱年份过后的湿润年份物种丰富度不受前一年降水的影响，说明荒漠草本植物层片具有较强的自我调节能力；自然处理下，不同年份草本植物旺盛期的存活数量与大气干旱程度(空气饱和差)呈显著负相关关系（R2值为0.611，P0.05），说明大气干旱程度更能表征荒漠草本植物生长峰值期的存活情况。
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