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61.
东洞庭湖保护区1989~1998年水禽栖息地动态研究   总被引:7,自引:0,他引:7  
栖息地的改变是全球生物多样性存在的最大威胁。利用卫星遥感技术和地理信息系统的空间分析功能,从景观尺度上研究了东洞庭湖自然保护区1989~1998年越冬水禽栖息地的动态变化特征,结果表明:1989~1998年水体、泥滩地、草滩地和水田等水禽适宜栖息地的面积在减小,破碎化程度有所增加,而芦苇滩地、旱地、林地、建成区这几类水禽分布较少栖息地类型的面积和破碎化程度的变化正好相反;近10年来水禽栖息地的变化比较明显,其中草滩地演变为芦苇滩地及水田改为旱作农田的变化最为突出,变化的面积分别占整个保护区面积的10.66%和6.13%。这些变化趋势意味着研究区近10年来水禽的适宜栖息地在退化。针对变化的原因,论文还对该区域生物多样性的保护与栖息地管理提出了可行的建议。  相似文献   
62.
本文初步分析了卧龙自然保护区野生植物资源的特点和存在的问题,提出了野生植物资源利用和保护的生态经济对策。  相似文献   
63.
对自然保护区生态旅游开发意义和特点进行阐述,并以武夷山自然保护区为例,探讨如何制订自然保护区生态旅游保护规划,提出管理监控的内容和方法。  相似文献   
64.
The characteristics of vertical and horizontal variations of lead element (Pb) in soil-plant system of vertical zone in Changbai Mountain National Nature Reserve(CNNR)were studied.The results showed that Pb concentrations in soils of vertical zone are all above 25mg/kg,and the average Pb concentration of each soil zone negatively correlates its degree of variation,i.e.brown coniferous forest soil zone has the lowest average Pb concentration of four soil zones,and the highest horizontal variation;however,mountain soddy forest soil has the highest average Pb concentration,and the lowest horizontal variation;the average concentration of plant Pb of each plant zone is lower than the worldwide average level of Pb in plant(Clarke),respectively,and plant Pb content order is consistent with soil Pb content order,but their horizontal variations are different from those in soil zones,the variation of mountain tundra forest zone is highest,but Betula ermanii forest zoner the lowest.Vertical variation of plant Pb is obviously higher than that in soils with variation coefficient of 89.76%;the enrichment capability of plant for Pb is depended on the plant types and the different organs of plant;parent material and parent rock,pH values,soil organic matter and soil particle fraction etc.are the main factors influencing variations of Pb contant in soil-plant system of vertical zone in CNNR.  相似文献   
65.
PM_(2.5) aerosol samples were collected over 12 hr and 24 hr intervals in an inland background area, Gongga Mountain National Nature Reserve(hereafter shortened to Gongga), during the summer of 2011. Polar organic tracers, inorganic ions and meteorological data were measured. The purpose of this work was to investigate the variation patterns, formation and sources of the secondary organic aerosol tracers in the studied atmosphere. The average concentrations of isoprene oxidation products, α-pinene oxidation products, β-caryophyllinic acid, sugars, sugar alcohols and anhydrosugars were 88.6 ± 106.1, 3.6 ± 5.7,0.13 ± 0.30, 13.6 ± 13.1, 31.9 ± 31.4 and 14.8 ± 10.7 ng/m3 respectively in all aerosol samples.The aged α-pinene second organic aerosol(SOA) tracers(i.e., 3-hydroxyglutraric acid(3 HGA), 3-hydroxy-2,2-dimethylglutaric acid(HDMGA), 3-acetylpentandioic acid(APDA) and 3-methyl-1,2,3-butanetricarboxylic acid(MBTCA)) correlated significantly with each other in the 24 hr PM2.5 aerosol samples, indicating that OH· is the major factor controlling the formation of these α-pinene SOA tracers. Using the positive matrix factorization(PMF) model and the tracer-based source apportionment method, we calculated that isoprene oxidation products, α-pinene oxidation products, sesquiterpene oxidation products, biomass burning, fungi spores and anthropogenic SOA accounted for 21.9% ± 5.5%, 8.4% ± 2.1%, 3.0% ± 0.7%, 5.2% ± 5.3%, 5.0% ± 6.2% and 31.4% ± 7.8% of organic carbon respectively during the sampling period.  相似文献   
66.
The geochemistry of natural waters in the Changtang Nature Reserve,northern Tibet,can help us understand the geology of catchments,and provide additional insight in surface processes that influence water chemistry such as rock weathering on the Qinghai–Tibet Plateau.However,severe natural conditions are responsible for a lack of scientific data for this area.This study represents the first investigation of the chemical composition of surface waters and weathering effects in two lake basins in the reserve(Lake Dogaicoring Qiangco and Lake Longwei Co).The results indicate that total dissolved solids(TDS)in the two lakes are significantly higher than in other gauged lakes on the Qinghai–Tibet Plateau,reaching 20–40 g/L,and that TDS of the tectonic lake(Lake Dogaicoring Qiangco)is significantly higher than that of the barrier lake(Lake Longwei Co).Na+and Cl-are the dominant ions in the lake waters as well as in the glacier-fed lake inflows,with chemical compositions mainly affected by halite weathering.In contrast,ion contents of inflowing rivers fed by nearby runoff are lower and concentrations of dominant ions are not significant.Evaporite,silicate,and carbonate weathering has relatively equal effects on these rivers.Due to their limited scope,small streams near the lakes are less affected by carbonate than by silicate weathering.  相似文献   
67.
Abstract: Extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout North America. The Flint Hills of Kansas and Oklahoma—the largest remaining tallgrass prairie—is important for grassland bird conservation despite supporting a major cattle industry. In 2004 and 2005, we assessed the community, population, and demographic responses of grassland birds to the predominant management practices (grazing, burning, and haying) of the region, including grasslands restored under the Conservation Reserve Program (CRP). We targeted 3 species at the core of this avian community: the Dickcissel (Spiza americana), Grasshopper Sparrow (Ammodramus savannarum), and Eastern Meadowlark (Sturnella magna). Bird diversity was higher in native prairie hayfields and grazed pastures than CRP fields, which were dominated by Dickcissels. Although Dickcissel density was highest in CRP, their nest success was highest and nest parasitism by Brown‐headed Cowbirds (Moluthrus ater) lowest in unburned hayfields (in 2004). Conversely, Grasshopper Sparrow density was highest in grazed pastures, but their nest success was lowest in these pastures and highest in burned hayfields, where cowbird parasitism was also lowest (in 2004). Management did not influence density and nest survival of Eastern Meadowlarks, which were uniformly low across the region. Nest success was extremely low (5–12%) for all 3 species in 2005, perhaps because of a record spring drought. Although the CRP has benefited grassland birds in agricultural landscapes, these areas may have lower habitat value in the context of native prairie. Hayfields may provide beneficial habitat for some grassland birds in the Flint Hills because they are mowed later in the breeding season than elsewhere in the Midwest. Widespread grazing and annual burning have homogenized habitat—and thus grassland‐bird responses—across the Flint Hills. Diversification of management practices could increase habitat heterogeneity and enhance the conservation potential of the Flint Hills for grassland birds.  相似文献   
68.
通过对扎龙自然保护区游客的问卷调查,分析了游客的生态旅游行为特征,进而对扎龙自然保护区生态旅游市场营销策略提出了相应的建议。  相似文献   
69.
The biophysical features of small islands (SI) distinguish them from other territories; isolation, small size and several anthropogenic pressures reduce the resilience of ecosystems and increase their vulnerability to global changes. Many SI have a shortage of infrastructures, institutions and technical/financial resources that hinder planning and require different integrated solutions. In Portugal, the National Ecological Reserve (NER) is legally binding for spatial planning instruments. It aims to defend natural values and areas of ecological value, or sensibility, or susceptible to natural hazards. However, the criteria for the design of NER are strictly set for mainland territory, not taking into account specific features of small islands. A case study of the Azores Archipelago is used to demonstrate that spatial planning instruments should be adapted to island contexts. Such adaptation will increase the effectiveness of their implementation in relation to the protection of natural resources, stability of biophysical structures and prevention of natural hazards. Observing the main differences between mainland and the Azores Archipelago it is possible to define a methodological transposition of the NER aims and goals into an island context. This approach is an answer to the constraints in effective adaptation of spatial planning instruments for islands.  相似文献   
70.
Extensive green areas generate a recognizable green identity of Ljubljana. Due to the challenges of climate change and urbanization the city's spatial policy highlights revitalization of degraded urban areas, preserving the quality and scope of the existing green network and the protection of multifunctional natural areas surrounding the city. Article describes the project of Rakova Jelša Park as a good example of these policies. With an NGO initiative a former degraded area with illegal dumping and non-indigenous vegetation was transformed into recreational park with increased biocultural diversity. Important lesson of the project is that opening up space for public use not only prevents degradation, but also improves the quality of urban ecosystems. One of the challenges for the city's future sustainable ecosystem development will be a more active cooperation with its citizens in the green infrastructure policy and later also a partial transfer of responsibility for green areas to them.  相似文献   
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