Flora and Vegetation of Tasiilaq,Formerly Angmagssalik,Southeast Greenland: A Comparison of Data Between Around 1900 and 2007

The changes in the vascular plant flora of Tasiilaq, low arctic Southeast Greenland, between around 1900 and 2007 were studied by comparing the data from historical literature with those of the field observations performed between the late 1960s and 2007. Since 1900, the percentage of widely distributed arctic species distinctly decreased, whereas that of the low arctic species somewhat increased, and boreal species hardly increased. Vegetation monitoring revealed minor changes and showed that several thermophilous and xerophilous species increased between 1968/1969 and 2007, whereas some hygrophilous species decreased. Repeated vegetation mapping of a shallow pond revealed conspicuous changes suggesting increased evaporation/precipitation ratios associated with environmental warming up and decreasing snow accumulation in winter, in line with results of previous investigations. In spite of climate warming, expansion of the town and increasing human impact, flora and vegetation on the whole appeared rather stable during the last 40 years without invading species or introductions.     

Multi-decadal changes in tundra environments and ecosystems: synthesis of the International Polar Year-Back to the Future project (IPY-BTF)

Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in subarctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies.     

Arsenic and mercury bioaccumulation in the aquatic plant, Vallisneria neotropicalis

Arsenic (As) and mercury (Hg) are among the most toxic metals/metalloids. The overall goal of this study was to investigate the bioaccumulation of these trace elements in Vallisneria neotropicalis, a key trophic species in aquatic environments. For this purpose, As and Hg concentrations were determined in sediments and natural populations of V. neotropicalis in sub-estuaries of Mobile Bay (Alabama, USA), differing with respect to past and present anthropogenic impact. Analyses indicate that the Fish River is the most contaminated among the sub-estuaries investigated; levels of As found in Fish River sediments fall within a range that could potentially cause adverse effects in biota. Sediment As concentrations were only moderately correlated with those in V. neotropicalis; no correlation was found between sediment and plant Hg levels. However, several parameters could have masked such potential relationships (e.g., differences in sediment characteristics and “biological dilution” phenomena). Results presented herein highlight the numerous parameters that can influence metal/metalloids accumulation in aquatic plants as well as species-specific responses to trace element contamination. Finally, this study underscores the need for further investigation into contaminant bioaccumulation in ecologically and economically important coastal environments.     

昆阳磷矿植被恢复地土壤肥力状况分析及评价

采用野外调查、室内分析并结合相关的方法,对昆阳磷矿人工林植被恢复样地土壤养分指标进行研究,以对矿区植被恢复地土壤肥力现状进行科学合理的评价。结果表明：矿区植被恢复地土壤的容重均小于18 g/cm,孔隙多,结构性较好,有益于植物的生长;植被恢复地土壤样本的有机质含量缺乏,全氮和碱解氮含量属于中等和较缺乏水平,全磷和有效磷、全钾和速效钾含量极为丰富。土壤有机质、有效磷,变异系数较大,分布不均匀,碱解氮、全氮、全磷、速效钾为中等变异的养分指标,变异系数相对小些,土壤中全钾呈弱变异,在土壤中的含量相对分布比较均匀。通过灰色关联度分析,得出研究区不同植被类型或不同年代组合恢复模式土壤肥力顺序为：2005年恢复的旱冬瓜+藏柏+麻栎林＞2006年恢复的旱冬瓜+藏柏+麻栎林＞2007年恢复的旱冬瓜+藏柏林＞平台覆土＞2005年恢复的旱冬瓜+藏柏林＞2005年恢复的旱冬瓜+藏柏+墨西哥柏林     

Effect of Coal Mine Soil Contamination on the Elemental Uptake and Distribution in Two Edible Amaranthus Species,A. dubius and A. hybridus

The impact of coal mine dump contaminated soil on the elemental uptake by two edible plants, namely, Amaranthus dubius (red herbs) and Amaranthus hybridus (green herbs), was studied by investigating their response and ability to tolerate and accumulate varying levels of elements in their roots and shoots. The vegetation was grown on varying amounts of contaminated soil, viz. 0%, 5%, 15%, 25% w/w using coal mine dump soil. The soil was analyzed for soil pH, cation exchange capacity (CEC), soil organic matter (SOM), moisture content, and selected heavy metals. The distribution of six metals, namely, Pb, Cd, Hg, Ni, Mn, and Fe, in roots, stem, and leaves of the plants was determined in two stages of growth after 5 weeks and 10 weeks. All soil and plant samples were microwave digested and subjected to heavy metal analysis using the ICP-OES, GFAAS, and CVAAS. The pH of the coal mine dump contaminated soil decreased with an increase in contamination. Both the SOM and CEC values decreased, which increases the availability of elements, by providing more binding sites in the soil. Relatively, the red herbs had higher elemental concentrations than the green herbs. Both plants recorded high manganese accumulation. No mercury was detected in the soils or plants.     

The distribution of macronutrients,anti-nutrients and essential elements in nettles,Laportea peduncularis susp. peduncularis (River nettle) and Urtica dioica (Stinging nettle)

Laportea peduncularis and Urtica dioica, which are popularly known as “Nettles” belong to the plant family Urticaceae and are consumed as green vegetables or used for their medicinal benefit in many countries in Africa, Asia, Europe and America. This study aimed at investigating the effect of cooking on the macronutrient, anti-nutrient and elemental composition of L. peduncularis and U. dioica leaves. The results showed a decrease in the crude fat, ash, carbohydrate and vitamin C content with cooking, but an increase in the vitamin E content. The anti-nutrient content (cyanides, phytates and saponins) increased slightly with cooking, while the oxalate content has decreased. The concentration of essential elements in cooked L. peduncularis leaves were found to be in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Cr > Ni > Co. Both raw and cooked leaves of nettles were found to be rich sources of macronutrients and essential elements and may be used as alternatives to commercially available nutrient supplements. Statistical analyses (principal component analysis and correlations) indicated that certain elements taken up by these plants were from common sources. Both positive and negative relationships between nutrients, anti-nutrients and elements were observed in the plant leaves.     

Relationships between pikas (Ochotona, mammalia) and vegetation in Tuva

The burrowing and trophic activities of four pika (Ochotona) species proved to be reflected in the horizontal structure of the biogeocenotic cover. Zoophytochores ofOchotona daurica andO. pallasi pricei burrows correspond to previously described ameboid zoophytochores. Burrows of pikas provide for the growth of pea shrubs (Caragana bungei, C leucophloea), with the formation of specific plant groups under their crowns and on rubble dug out by pikas. In ecosystems of placers, zoophytochores are formed owing to the presence of pika food stores and lavatories, which are the main substrate for vascular plants first appearing among the stones. General ecological (and successional) series characterizing the overgrowing of placers is as follows: (1) separate spots of vegetation with poor floristic composition at the sites of pika food stores (stacklets); (2) groups of spots and simplest complexes; and (3) complex plant communities of pika colonies. Food stores of pikas in Tuva were analyzed.     

20年间艾比湖流域植被覆盖度景观格局变化

选取艾比湖流域1990年、2001年、2011年同期（9月）3期I．and．satTM遥感影像,基于归一化植被指数NDVI,提取植被覆盖等级图,利用ArcGIS9．3和Fragstas3．3对该流域植被景观的变化进行了分析研究。结果表明：1990—2011年,该流域植被覆盖度变化明显,低植被覆盖区和较低植被覆盖区都有所减少,分别由1990年的34．05％和32．94％减少到2011年的32．8％和24．06％;较高植被覆盖区和高植被覆盖区有所增加,分别由8．49％和5．20％增长到15．13％和9．83％,但水域面积退化明显,由1990年的525．9765km2缩小至494．9876km2,减少了30．9889km2,退缩幅度达O．4％;最大斑块指数（LPI）由17．04上升到21．10,香农多样性指数（SHDI）和香农均势度指数（SHEI）分别由1．5387和0．8588增长到1．6395和0．9150。表明艾比湖流域景观格局混杂程度愈来愈高,空间异质性在逐年加强,总体空间格局向破碎化趋势发展。     

高光谱数据在“十一五”期间生态环境状况监测中的应用

高光谱遥感以"图谱合一"等特点在生物多样性监测、土壤退化、植被重金属污染监测、生物量估算等方面都有广泛应用。通过长时间序列高光谱反演数据NDVI和NPP,较好的反映了"十一五"期间新疆生态环境V字型的变化趋势,基本符合5年新疆生态环境变化状况。高光谱数据反演技术是开展生态环境宏观监测的有效手段之一。     

基于遥感方法的小流域土壤侵蚀研究

探讨了利用遥感技术进行小流域土壤侵蚀计算的方法。应用通用土壤侵蚀方程,借助RS和GIS技术,对模型各参数因子进行精确计算,实现了基于栅格信息的土壤侵蚀计算模型。选择黄河皇甫川五分地沟小流域作为典型研究区,讨论了适宜植被盖度对减小土壤侵蚀模数的影响。