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821.
The effects of grassland degradation on plant diversity,primary productivity,and soil fertility in the alpine region of Asia’s headwaters 总被引:1,自引:0,他引:1
Xuexia Wang Shikui Dong Bing Yang Yuanyuan Li Xukun Su 《Environmental monitoring and assessment》2014,186(10):6903-6917
A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland. 相似文献
822.
涉刑环境监测中有待解决的若干技术问题及对策建议 总被引:2,自引:0,他引:2
指出了涉刑环境监测工作中,司法鉴定机构的资质及监测数据认可、环保标准与规范、固体废物监测等方面存在的问题。提出,涉刑监测单位应尽快获取司法鉴定机构资质;国家层面应给出涉刑监测数据认可的指导性意见;加快环境标准制修订工作,增强标准的适用性和可操作性;修订《危险废物鉴别技术规范》(HJ/T 298-2007)和相应系列鉴别标准。 相似文献
823.
824.
825.
城市固体废物优化管理模型及管理成本影响因素研究 总被引:2,自引:0,他引:2
采用不确定性多目标动态优化模型,以优化环境和经济为目标,对中国佛山市固体废物管理进行规划.结果表明,该模型能大幅度降低固体废物管理与处理成本,节省财政支出.研究得出影响固体废物总处理费用的3个重要影响因素为产生量、回收量、处理容量.针对以上3个因素深入分析比较,提出了广义和狭义的综合处理技术,这是经济、环保、可行的技术策略:首先,将广义综合处理应用到实际中,采用分类回收、压缩收集、优化模型对废物进行合理配置,尽量降低经济成本和环境影响;其次,从狭义角度出发,采用多种技术组合,达到处理率高、资源化程度高、环境影响小的目的. 相似文献
826.
827.
代谢表面活性剂菌处理含油污泥的研究 总被引:6,自引:0,他引:6
试验采用异位生物修复技术堆肥法,对某炼厂油泥进行生物修复处理研究.用微生物代谢的表面活性剂对油泥进行预处理,洗脱油泥中部分油分后进行堆肥试验,投加从油田含油土壤中获得的以石油为唯一碳源、代谢高效生物表面活性剂的微生物C-2菌、F-2菌以及无机营养物和疏松剂(锯末),降解油泥中的石油污染物.经过外源微生物和内源微生物共同作用120 d,油泥中的石油烃总量由22 910 mg/kg下降到3 000 mg/kg以下.试验利用色谱-质谱联用方法分析了降解前后石油组分的变化.菌株经传统方法鉴定为蜡状芽孢杆菌、枯草芽孢杆菌. 相似文献
828.
德兴铜矿周边地区土壤酶活性研究 总被引:1,自引:1,他引:0
采用逐步多元回归和主成分分析的方法研究了德兴铜矿周边土壤中重金属和土壤酶活性的关系.结果表明:德兴铜矿周边各功能区均受到不同程度的Cu、Cd污染,Pb、Zn未超过《土壤环境质量标准》(GB 15618--1995)二级标准;各功能区土壤酶活性有显著差别,逐步回归分析表明土壤酶活性与Cu、Zn全量、生物可利用态Cu含量有显著线性关系,而与Cd、Pb无明显相关;土壤酶活性和生物可利用态Cu呈负线性关系,而与残渣态Cu有正线性关系.主成分分析显示,土壤酶信息系统的第1、第2主成分可反映酶活性总变异的96.27%,根据第1主成分对功能区酶活性的分类结果与土壤生物可利用态Cu含量的分类结果基本一致,提示土壤酶活性指标可以反映土壤生物可利用态Cu含量. 相似文献
829.
830.
For marine organisms, decoupling between the planktonic larval stage and the benthic-associated juvenile stage can lead to
variable patterns of population replenishment, which have the potential to influence the effectiveness of marine reserves.
We measured spatial and temporal variability in larval supply and recruitment of fishes to coral reefs of different protection
levels and tested whether protection level influenced the relationship between supply and recruitment. We sampled pre-settlement
larvae and newly settled recruits from four reefs (two reserves and two non-reserves) in the Florida Keys National Marine
Sanctuary, USA. Replicate point measures of larval supply over 14 months and 17 monthly measurements of recruitment varied
significantly among months and sites. Sites with the same protection level had significantly different patterns of larval
supply as well as larval and recruit diversity, but recruitment magnitude differed only by protection level, where densities
were greater at reserves. Differences in larval supply among sites included two particularly large peaks in larval abundance
at one site, possibly associated with the observed passage of small-scale oceanographic features. To examine whether relationships
between larval supply and recruitment varied by protection level, we selected one species that was present in both the light
trap samples and the monthly recruitment surveys. Recruitment of the bicolor damselfish Stegastes partitus was significantly and positively related to larval supply at three of the four sites thus, protection level did not influence
this linkage. Since local variability among sites can lead to spatial differences in population replenishment, characterization
of larval supply and recruitment to potential marine reserve sites may help to identify optimal locations in a region and
contribute to more effective reserve design. 相似文献