Subjects: Biology >> Ecology submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： Many studies on grassland ecosystem degradation have been performed using vegetation coverage orproductivity indexes for evaluation. However, it is difficult to comprehensively evaluate different degrees ofgrassland degradation using a single evaluation index. Taking Bayinbuluk grassland in the Xinjiang TianshanMountains as a research object, a remote sensing method for evaluating grassland degradation based onstandardized processing sub- index coupling was proposed. The grassland vegetation coverage, average grasslayer height, and total grass yield were selected to determine the weight of the three indexes by principalcomponent analysis. The Min-Max standardized method was introduced to construct the grassland degradationindex (GDI). Finally, the degree of degradation of Bayinbuluk grassland in the Xinjiang Tianshan Mountains wasdetermined through Landsat image inversion and reasonable classification of the rate of change of grasslanddegradation index from 1986 to 2021. The results showed that GDIg has the best correlation with NDVI. In 2021,the proportion of undegraded area of Bayinbuluk grassland relative to the total area was 60.51%. The degree ofdegradation of different grassland types showed clear differences. The spatial distribution showed a trend of basinto mountain degradation. The GDIrs model could be applied to other years through the radiation registrationmethod. The degree of degradation of Bayinbuluk grassland significantly improved from 2000 to 2009 andslightly fluctuated from 2009 to 2021. The results of this research provide robust data support and a theoreticalbasis for guiding evaluation of the degree of degradation of Bayinbuluk grassland and protecting the grasslandecosystem.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-04-26 Cooperative journals: 《干旱区研究》
Abstract：为探究氮添加对高寒草原生态系统土壤酶活性的影响，于2018年在中国科学院巴音布鲁克草原生态系统研究站，选择4个氮添加水平（对照，N0，0 kg·hm-2·a-1；低氮，N1，10 kg·hm-2·a-1；中氮，N3，30 kg·hm-2·a-1；高氮，N9，90 kg·hm-2·a-1），开展土壤酶活性对氮添加响应的研究，分析土壤酶活性对氮添加的响应特点，土壤酶化学计量比以及土壤酶活性与土壤环境因子的关系。结果表明：与对照相比，氮添加在N3水平显著增加β-1,4葡萄糖苷酶（βG）、β-D-纤维二糖水解酶（CBH）和β-1,4木糖苷酶（βX）酶活性（P < 0.05），N1和N3水平显著增加碱性磷酸酶（AKP）活性（P < 0.05），N3水平显著降低多酚氧化酶（PPO）活性（P < 0.05），氮添加对亮氨酸氨基肽酶（LAP）活性影响不显著，N3水平下显著增加N-乙酰-β-D氨基葡萄糖苷酶（NAG）活性（P < 0.05）。相关分析表明，8种土壤酶活性均与土壤有机碳（SOC、NAG除外）和总磷（TP）显著相关，与土壤总氮（TN）不相关。研究区土壤酶活性C∶N∶P化学计量比为1∶1∶1.2，与全球生态系统的土壤酶活性C∶N∶P的比值1∶1∶1相偏离，表明该研究区土壤微生物生长受磷素限制。冗余分析（RDA）进一步揭示出土壤有机碳和土壤全磷含量是影响土壤酶活性的主要因子。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区研究》
Abstract：人类活动和气候变化导致的大气氮沉降急剧升高，将会影响高寒草原植物养分循环。为了研究氮沉降对高寒草原植物养分含量及生态化学计量学特征的影响。依托2009年在新疆天山巴音布鲁克高寒草原设置的长期氮沉降研究平台，于2017年7月和10月采集溚草（Koeleria cristata）、二裂委陵菜（Potentilla bifurca）和天山赖草（Leymus tianschanicus）3种植物的成熟叶和老叶，分析3种植物叶片N、P元素生态化学计量对不同施氮水平的响应规律。结果表明：① 3种植物养分浓度及其化学计量比在成熟叶和老叶之间存在较大差异，成熟叶和老叶的N、P含量分别为12.78 mg·g-1、0.88 mg·g-1和6.88 mg·g-1、0.46 mg·g-1。3种植物成熟叶和老叶的N元素含量均为：二裂委陵菜>天山赖草>溚草,P元素含量同N元素含量趋势一致；② 氮添加增加了成熟叶和老叶N浓度，分别达12%和48%；成熟叶与老叶P浓度对氮添加的响应规律不一致，成熟叶P浓度对氮添加的响应与物种有关，而老叶P浓度呈一致的下降趋势；氮添加对成熟叶和老叶N∶P的比值影响亦不同，其中相对于成熟叶，老叶的N∶P呈显著增加趋势。③ 植物叶片的N元素、P元素和N∶P比三者之间的相关分析表明:N元素和N∶P之间呈显著正相关关系(P0.05)，而二裂委陵菜呈现一定的差异性，在生长旺盛期二裂委陵菜叶片N与P元素呈显著的正相关、枯黄期呈显著的负相关(P<0.05)。表明长期氮的添加显著影响了3种植物叶片的养分含量和生态化学计量，不同物种间存在一定差异，未来氮沉降升高将会影响天山山地草原的植物养分循环。
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