Wetland effects on lake water quality in the Minneapolis/St. Paul metropolitan area     

Naomi E. Detenbeck  Carol A. Johnston  Gerald J. Niemi 《Landscape Ecology》1993,8(1):39-61

A method developed to evaluate the cumulative effect of wetland mosaics on water quality was applied to 33 lake watersheds in the seven-county region surrounding Minneapolis-St. Paul, Minnesota. A geographic information system (GIS) was used to record and measure landscape variables derived from aerial photos. Twenty-seven watershed land-use and land-cover variables were reduced to eight principal components which described 85% of the variance among watersheds. Relationships between lake water quality variables and the first six principal components plus an index of lake mixis were analyzed through stepwise multiple regression analysis. A combination of three landscape components (wetland/watershed area, agriculture/wetlands, and forest/soils components) explained 49% of the variance in a trophic state index, even though most of the lakes examined were already highly eutrophic, and thus were influenced by internal loading. The regression equations explained a range of 14 to 76% of the variation in individual water quality variables. Forested land-use was associated with lower lake trophic state, chloride, and lead. High lake trophic state was associated with agricultural land-use and with wetland distance from the lake of interest. The extent of wetlands was associated with low total lead and high color in lakes downstream. Wet meadows or herbaceous, seasonally-flooded wetlands contributed more to lake water color than did cattail marshes.  相似文献   

放牧管理对西藏高寒沼泽植物群落结构和土壤碳氮的影响     

曲广鹏  参木友  赵景学  田莉华 《草原与草坪》2016,(4):27-33

对西藏当雄县3种不同放牧管理模式(冬季放牧、冬春季放牧和全年放牧)下的高寒沼泽的植物群落结构和土壤碳氮进行了调查。调查发现,3种放牧管理模式下的高寒沼泽植物群落总盖度差异不显著,而优势物种藏嵩草的高度和盖度差异显著;放牧管理对沼泽群落结构和物种多样性影响较大,随着放牧强度的增加,物种丰富度增加;放牧利用显著降低了高寒沼泽湿地群落优势物种藏嵩草的高度和盖度,其优势度也显著降低,使得高寒沼泽逐渐退化。冬季放牧、冬春季放牧和全年放牧沼泽地上生物量和地下生物量依次降低。同时,随着放牧强度的增加,高寒沼泽表层土壤有机碳氮的含量也显著降低,且高寒沼泽表层土壤碳氮与地上和地下生物量显著正相关。通过对比分析,冬季放牧是当前西藏高寒沼泽较好的放牧管理模式。  相似文献   

新兴绿色技术——水生植物修复技术   总被引：5，自引：0，他引：5  

任照阳  邓春光 《节水灌溉》2007,(4):17-19

水体富营养化治理已成为当今世界性难题,解决水体富营养化问题的关键是调控水生生态系统结构,使其恢复自然、健康和稳定的水生生态系统功能,提高水生生态系统的生物净化能力.水生植物是水生生态系统中最重要的初级生产者,在水生生态系统物质和能量循环中处于十分重要的地位.水生植物修复技术具有投资、维护和运行费用低,管理简便,处理效果好,可改善和恢复生态环境,回收资源和能源以及收获经济植物等优点,浮岛技术、人工湿地等技术也取得了显著的成就.植物修复技术作为一种绿色技术,将会有更加广阔的发展天地.  相似文献   

Quantifying the nitrogen retention capacity of natural wetlands in the large-scale drainage basin of the Baltic Sea   总被引：3，自引：0，他引：3  

Jansson  Åsa  Folke  Carl  Langaas  Sindre 《Landscape Ecology》1998,13(4):249-262

We estimate the nitrogen retention capacity of natural wetlands in the 1.7 million km² Baltic Sea drainage basin, using a wetland GIS data base. There are approximately 138,000 km² of wetlands (bogs and fens) in the Baltic Sea drainage basin, corresponding to 8% of the area. The input of nitrogen to natural wetlands from atmospheric deposition was estimated to 55,000–161,000 ton y¹. A map of the deposition of both wet and dry nitrogen is presented. The input from the human population was estimated to 255,000 ton y¹ in terms of excretory release in processed sewage water. There may also be leakage from forests and agricultural land into the wetlands. Due to lack of data on hydrology and topography, such potential nitrogen sources are not accounted for here. The capacity of the wetlands to retain the atmospheric deposition of nitrogen was estimated to 34,000–99,000 ton y¹. The potential retention by wetlands was estimated to 57,000–145,000 ton y¹ when the nitrogen input from the human population was added. If drained wetlands were to be restored and their area added to the present wetland area, the nitrogen retention capacity was estimated to increase to 196,000–261,000 ton y¹. Our results indicate that existing natural wetlands in the Baltic Sea drainage basin annually can retain an amount of nitrogen which corresponds to about 5–13% of annual total (natural and anthropogenic) nitrogen emissions entering the Baltic Sea. The ecosystem retention service performed by wetlands accounts for a substantial nitrogen removal, thereby reducing the eutrophication of the Baltic Sea.  相似文献   

红树林海岸生物多样性专项库的设计     

王蕙 《农业图书情报学刊》2007,19(8):175-178

为了加强对红树林生态环境保护的宣传力度，增强图书馆对外服务的功能，满足对红树林海岸生物多样性信息编目、分类等资料管理需求，采用目前先进的Web技术、数据库技术、数据处理技术构建了红树林海岸生物多样性信息管理系统，较为详细地讨论了构建专项库的意义以及关键技术。  相似文献   

Bacterial community structure of nirK-bearing denitrifiers and the development of properties of soils in created mitigation wetlands     

《Applied soil ecology》2013

We investigated the abundance and genetic heterogeneity of bacterial nitrite reductase genes (nir) and soil structural properties in created and natural freshwater wetlands in the Virginia piedmont. Soil attributes included soil organic matter (SOM), total organic carbon (TOC), total nitrogen (TN), pH, gravimetric soil moisture (GSM), and bulk density (D_b). A subset of soil attributes were analyzed across the sites, using euclidean cluster analysis, resulting in three soil condition (SC) groups of increasing wetland soil development (i.e., SC1 < SC2 < SC3; less to more developed or matured) as measured by accumulation of TOC, TN, the increase of GSM, and the decrease of D_b. There were no difference found in the bacterial community diversity between the groups (p = 0.4). NirK gene copies detected ranged between 3.6 × 10⁴ and 3.4 × 10⁷ copies g⁻¹ soil and were significantly higher in the most developed soil group, SC3, than in the least developed soil group, SC1. However, the gene copies were lowest in SC2 that had a significantly higher soil pH (~6.6) than the other two SC groups (~5.3). The same pattern was found in denitrifying enzyme activity (DEA) on a companion study where DEA was found negatively correlated with soil pH. Gene fragments were amplified and products were screened by terminal restriction fragment length polymorphism (T-RFLP) analysis. Among 146 different T-RFs identified, fourteen were dominant and together made up more than 65% of all detected fragments. While SC groups did not relate to whole nirK communities, most soil properties that identified SC groups did significantly correlate to dominant members of the community.  相似文献   

珠海市淇澳岛红树林引种扩种问题的探讨   总被引：16，自引：1，他引：16  

陈玉军  郑松发  廖宝文  谢德兴  苏润鸿  郑德璋 《广东林业科技》2002,18(2):31-36

文章论述了珠海淇澳岛引种扩种红树植物的重要意义；分析了引种无瓣海桑对红树资源的恢复，物种多样性和林分质量的提高，乡土植物的天然更新和扩散，大米草的控制等作用；并探讨了无瓣海桑引种对生态的影响。最后还提出了红树林引种扩种需要加强的措施。  相似文献   

广州市红树林资源现状及其保护利用对策   总被引：1，自引：0，他引：1  

刘秋红 《福建林业科技》2005,32(2):125-128,136

概述了广州红树林资源现状,分析了广州市红树林资源保护工作中急需解决的主要问题,并提出解决问题的相关建议。  相似文献   

海南岛清澜港红树树种适应生境能力与水平分布^*   总被引：6，自引：0，他引：6       下载免费PDF全文

郑德璋  廖宝文  郑松发  许达桂  韩智 《林业科学研究》1995,8(1):67-72

红树植物的器官形态变异反映了它们对于不同潮间带生境的适应能力，灰色聚类分析结果表明杯萼海桑、海桑、正红树属于适应潮间带生境能力强的种类，木榄、海莲属于适应潮间带生境弱的种类。适应能力强者在低、中潮滩组建群落，适应能力低者在高、中潮滩组建群落。随潮间带淤积升高，适应能力强者不断向外占领裸滩，适应能力弱者不断侵入适应能力强者的迹地。  相似文献   

红树植物地面反射光谱特征研究   总被引：1，自引：1，他引：1  

翁强  卢昌义 《福建林业科技》2006,33(3):14-19

结合使用野外便携式光谱仪对九龙江口红树林保护区白骨壤、秋茄、桐花树3种红树植物的叶冠表观光谱的测量结果,系统分析比较了红树植物叶冠反射光谱特征及其差异;并在一个潮间带底质遥感信息处理平台上对研究地点进行基于表观光谱特征的白骨壤和秋茄的SPOT卫星遥感图像分类;最后讨论了红树光谱研究中存在的问题。  相似文献