若羌,且末两县境内的阿尔金山,昆仑山草场类型及其利用

若羌、且末两县境内的阿尔金山、昆仑山草场类型较丰富。据调查统计有：9个草场类型，63个草场型。总面积达405.4×104hm2，可利用面积达269．4×104hm2。该地区范围虽大，但单地生产力低，应严格实行季节轮牧制，控制放牧牲畜的数量，以现有放牧26万只羊单位较为适宜。对尚未开发利用的草地不宜开发利用，因为在这一区域常年栖息着多种国家级一、二类保护动物，所以应将这一区域作为自然保护区，对研究动植物繁衍具有特殊的意义。     

新疆和田—若羌地区土地荒漠化评价

基于Landsat TM/ETM和OLI卫星遥感数据,应用植被覆盖率法,对新疆和田—若羌地区的土地荒漠化进行了评价,并分析其影响因素。结果表明:1985-2015年,研究区重度荒漠化、中度荒漠化区域面积呈减小趋势;而轻度荒漠化、非荒漠化区域面积则呈增加趋势。研究区荒漠化的趋势变化与沙地戈壁以及耕地面积的变化密切相关,和田—若羌地区沙地戈壁面积在30年间减小4.19×105hm2,总体下降率为23.3%;而耕地面积则增加了1.03×105hm2,增加率为2.6%。     

试论绿洲外缘沙漠化的治理

新疆是干旱、半干旱地区，绿洲面积仅占全区总土地面积的３．５％，新老绿洲均处于荒漠包围之中，绿洲外缘是沙漠化的策源地。绿洲外缘沙漠化的治理，是当前新疆治沙工程的重点区域。根据绿洲外缘的生态地位和沙漠化逆转的可能性，阐明了治理目标和主要途径，并建议自治区人民政府和各级职能部门重视绿洲外缘沙漠化的治理。     

沙漠化

我刚才出去买冰棍,回来的时候看到学校的操场上正在卸沙子呢{沙子堆得像小山一样。 小丽,我要用沙子做个“巧克力”蛋糕给你!经过艰苦地努力.我们从沙漠的手中夺回了片片绿洲,使许多地区的沙漠化状况得到改善,但形势依然十分严峻,所有人都要提高警惕! 目前,地球上沙漠及沙漠化土地面积共4560 8万平方千米,占陆地总面积的35%。世界上150多个国家和地区中,大约三分之二受到沙漠化影响,15%人口受到沙漠化威胁沙漠化@元素     

防止土地沙化 保护绿洲环境——南疆生态环境考察报告

新疆地处欧亚大陆腹地,气候干旱、植被稀疏,是沙漠化严重威协的地区之一。其中尤以南疆地区为甚。近年来,社会各界就南疆地区无度樵采、破坏植被、塔河下游断流、绿色走廊日趋衰败导致土地沙化加剧、生态环境继续遭受破坏的呼吁、建议越来越多,在自治区六届六次人大常委会上,十八位常委提出的关于保护环境的议案被列为一号议案。     

青海省土地沙漠化及其防治

一、概述青海省是我国土地沙漠化严重地区之一。全省沙漠面积居全国第三位,主要分布于柴达木盆地、共和盆地和青海湖盆地,即大都分布于干旱、半干旱的荒漠和草原地带。青海沙漠化土地与沙漠分布基本上是一致的,主要分布于柴达木盆地、共和盆地和青海湖盆地的东北部,其次是青南高原西部和祁连山西部。青海土地沙漠化过程,可分为两种类型。一是沙漠化的历史过程,即沙漠化的发生发展都是在历史时期内所进行的。据考证,柴达木盆地西南部祁曼塔格山下的大片沙漠,历史上曾是一片草原景观,经     

浅析祁连山国家公园青海片区沙化土地动态变化

本文通过对2014年、2019年祁连山国家公园青海片区沙化土地面积数据进行对比分析，得出了2019年较2014年沙化土地面积略有增加，并从气候变化、人为因素方面分析了变化原因，同时提出了综合性结论及建议。     

伊犁河谷退耕还草的模式及生态经济效益探讨

退耕还林还草、进行生态环境建设是我国政府制定的一项战略性措施。伊犁河谷需要退耕还草的面积为14.13×104hm2,河谷自然地理条件较复杂,不同地域水、土、光、热条件差异较大,本文就伊犁河谷不同地域退耕还草的模式、生态经济效益及相关技术问题进行了探讨。     

格尔木市沙漠现状与发展趋势

通过分析沙漠化土地现状及分布情况，探讨了格尔木地区土地沙漠化的形成因素，发展趋势，并提出了防治措施及建议。     

玛纳斯县新湖农场植物治沙效益评估

利用新湖农场1998—2007年气象、社会、经济资料及实测植被、土壤数据，分析了近10年来防沙治沙情况，并选取定量、定性指标，建立效益评估模型，对植物治沙产生效益进行评估。结果表明：植被覆盖率由1990年1．63％提高到2007年5．37％，植物种类、土壤碱解N、速效P随栽植年限增加而上升，沙化面积比例由1990年的2．90％减少到2006年的0．59％，风沙天气由1998年的27次减少到2007年的4次；农场土地利用结构得到优化，人均林草面积由1990年人均0．02hm2增加到2006年0．15hm2。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.     

Effect of Light on Biodegradation of Estrone, 17β‐Estradiol,and 17α‐Ethinylestradiol in Stream Sediment

Biodegradation of [A‐ring ¹⁴C] Estrone (E1), 17β‐estradiol (E2), and 17α‐ethinylestradiol (EE2) to ¹⁴CO₂ was investigated under light and dark conditions in microcosms containing epilithon or sediment collected from Boulder Creek, Colorado. Mineralization of the estrogen A‐ring was observed in all sediment treatments, but not epilithon treatments. No difference in net mineralization between light and dark treatments was observed for ¹⁴C‐E2. Net mineralization of ¹⁴C‐E1 and ¹⁴C‐EE2 was enhanced in light treatments. Extents of ¹⁴CO₂ accumulation and rates of mineralization were significantly greater for E2 than E1 under dark conditions, but were comparable under light conditions. These results indicate substantial differences in the uptake and metabolism of E1 and E2 in the environment and suggest biorecalcitrance of E1 relative to E2 in light‐limited environments. The extent of ¹⁴CO₂ accumulation and rate of mineralization for EE2 in dark treatments were less than half of that observed for E2 and generally lower than for E1, consistent with previous reports of EE2 biorecalcitrance. However, ¹⁴CO₂ accumulation and rates of mineralization were comparable for EE2, E2, and E1 under light conditions. These results indicate photoactivation and/or phototransformation/photodegradation processes can substantially enhance heterotrophic biodegradation of estrogens in sunlit environments and may play an important role in estrogen transport and attenuation.