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1.
通过对新疆那拉提高寒草甸天然草地进行围栏(3、5、30 a)和自由放牧处理,探讨草地不同利用方式对草地植物多样性和生物量的影响。结果表明,在自由放牧制度下,由于干扰过于剧烈,草地已呈退化趋势,物种多样性和生物量均较低;在围栏草地中,随着围封年限的增加,群落高度、盖度、地上生物量逐渐增加;地上生物量的变化趋势为放牧草地围栏3 a草地围栏5 a草地围栏30 a草地。  相似文献   

2.
以1989—2016年玛纳斯河流域TM/OLI遥感影像为数据源,利用混合像元分解技术,计算玛纳斯河流域草地总覆盖度和裸沙面积。在此基础上通过监测年与基期年的比较,计算草地覆盖度相对基期年的减少率和裸沙面积相对基期年的增加率两个监测指标,依据《天然草地退化、沙化、盐渍化的分级指标》(GB 19377—2003),对计算出的两个指标分别进行沙化等级评定和赋值,将两种评定结果相综合来监测草地沙化。结果表明,玛纳斯河流域近30年来荒漠草地沙漠化总体呈现先增加后降低的趋势。分析表明,玛纳斯河流域草地沙化是人为和自然因素双重作用的结果。  相似文献   

3.
陈旭 《干旱环境监测》2004,18(2):106-108
利用美国陆地资源卫星TM5遥感信息,调查分析了鞍山市森林资源现状。结果表明,鞍山市共有森林资源466933.52hm^2,占全市土地面积的50.32%,其中灌木林占森林面积的81.11%。在此基础上,分析了存在的主要问题,并提出了恢复途径及生态建设模式。  相似文献   

4.
淮安市城市生态足迹分析   总被引:3,自引:0,他引:3       下载免费PDF全文
在介绍生态足迹的计算模型的基础上,计算了淮安市2006年的生态足迹。结果表明,2006年淮安市人均生态足迹是2.53hm^2,人均生态承载力仅为0.82hm^2,人均生态赤字则为1.71hm^2,反映了淮安市的生产、生活强度超过了生态系统的承载能力。  相似文献   

5.
在帕米尔高原高寒草原地区,选择了4个自然放牧梯度、处于3种典型退化阶段的草地为研究对象,进行了土壤草毡表层加厚引起的系统氮、磷分配和水分利用的变化过程的研究。结果表明,随着放牧强度的增加,草地禾本科植物逐渐减少,蒿类植物成为优势种群,土壤草毡表层逐渐加厚,从新疆银穗草+硬叶苔草群落的3.02±0.53 cm发育到高山绢蒿、西藏亚菊群落阶段的8.24±0.53 cm;矮生嵩草群落使系统生长需要的氮、磷养分数量急剧增加,分别从12 g/m2到23 g/m2、0.84 g/m2到1.7 g/m2,成为生物养分固定累积于土壤;同时致密加厚的、特别是老化死亡的草毡表层的存在,使土壤水分的渗透速率从新疆银穗草+硬叶苔草群落的1.94 mm/min降低到小嵩草群落的1.38mm/min,使系统接受自然降水的能力大大减弱,水分的利用效率极低,而根系数量的急剧增长导致需水量的增加,土壤湿度逐渐降低,降幅最大达到18.85%。草毡表层加厚导致的营养供求失调、干旱胁迫是引起高寒草地退化的内在原因之一。  相似文献   

6.
用二氯甲烷提取稻田水和水稻植株样品中的丙草胺,稻田土壤样品用二氯甲烷-甲醇混合溶剂(体积比为9∶1)提取,再用高效液相色谱仪测定。方法在0.02 mg/L~2.00 mg/L的范围内线性良好,相关系数为0.9998;稻田水、土壤,水稻植株中丙草胺的检出限分别为0.001 mg/L、0.005 mg/kg、0.01 mg/kg;对稻田水、土壤和水稻植株分别做3个浓度水平的加标回收试验,重复5次,平均回收率在75.5%~84.7%之间,测定结果的相对标准偏差为2.0%~10.5%。  相似文献   

7.
新疆实施退牧还草工程以来,不仅有效的保护了天然草地,改善了区域生态环境,而且促进了畜牧业生产结构、牧区生产和生活方式的改变,提高了牧民的收入。但在工程实施的同时,仍存在建设内容单一、规划设计、草地围栏管护与利用监管不落实、饲料粮补助标准偏低等问题。如何因地制宜做好退牧还草工程,本文针对北疆退牧还草工程实施中存在的问题,提出了相应的对策与建议。  相似文献   

8.
乌鲁木齐地区湿地现状及保护对策   总被引:2,自引:0,他引:2  
通过对乌鲁木齐地区湿地现状的调查可知,乌鲁木齐地区现有湿地21612hm^2,占土地总面积的1.94%,由于不合理的水土开发,目前每年有30hm^2湿地因开垦而遭到人为破坏,主要特征为有害植物增加,生物多样性减少,生产力下降。为此,提出乌鲁木齐地区保护湿地的具体措施和对策。  相似文献   

9.
采用归一化植被指数、景观多样性指数、景观均匀度指数等技术指标,评价那棱格勒河下游绿洲的生态环境现状。结果表明:那棱格勒河下游绿洲区主要为中植被覆盖(覆盖度30%~60%)区域,占绿洲区总面积的42.83%;低植被覆盖类型(覆盖度10%~30%)和高植被覆盖类型(覆盖度60%)次之。极低植被覆盖(覆盖度10%)区域最少,占绿洲区总面积的3.96%。稀疏草地和荒漠为该区域的优势景观,自然生产力等级低,生态系统受外界干扰后难以恢复,极易发生退化与沙化,系统的恢复稳定性与阻抗稳定性都较弱。  相似文献   

10.
运用 InVEST模型和PLUS模型动态模拟泾河流域未来不同发展情景下碳储量变化情况,对当前十年及未来十年土地利用类型变化及其对碳储量的影响进行评估。结果表明:2030年经济发展和生态发展情景下,泾河流域碳储量分别为1.068×109t和1.082×109t,与2020年相比,经济发展情景下碳储量减少9×106t,生态发展情景下碳储量增加5×106t。控制草地、林地、湿地、水域退化和建设用地扩张可以有效提高生态系统碳储量;基于生态发展情景下的土地利用方式更有助于提升泾河流域碳汇能力,实现区域可持续发展。  相似文献   

11.
This study analyzes the results of the first 5 years of long-term environmental monitoring of the dynamics of coastal vegetation communities in southwestern Taiwan. Seven permanent plots were established in major vegetation communities, including grassland, windbreak forest, and secondary succession forest. Results showed that species richness decreased yearly in grasslands but fluctuated moderately in the forest plots. A Jaccard similarity coefficient was used to evaluate the similarities of species composition between different monitoring years. Species composition changed rapidly in grassland sites, with the similarity coefficient dropping from 82 to 29% in 5 years. The similarity coefficient of vegetation in the compositehardwood forest dropped from 80 to 50%, indicating that at least half the species were the same as those in the beginning and that the composition of forest communities was more stable than that of grassland communities. Dominant species in the forest community changed gradually during the monitoring period. The original planting of Casuarina equisetifolia in windbreak forests decreased year by year in most of the plots, while Cerbera manghas and Ficus microcarpa became the dominant species. The trend of replacement of dominant species indicates that most of the vegetation communities are still in successional stages.  相似文献   

12.
新疆草原利用与保护现状及对策建议   总被引:2,自引:0,他引:2  
通过对新疆目前的草原利用与保护现状及存在的问题进行分析,提出了解决新疆畜牧业发展的思路及实施的牧民定居工程、人工草料地建设工程、牧区水利工程、退牧还草工程和牧民转移等草原建设的五大重点工程。  相似文献   

13.
呼伦贝尔地区草原表层土壤中总有机碳与有机质初探   总被引:1,自引:0,他引:1  
通过非分散红外线吸收法测定呼伦贝尔地区具有代表性的16个草原表层土壤(0~20 cm)中总有机碳、溶解性有机碳,使用重铬酸钾容量法测定有机质,并对其总有机碳与有机质水平及两者相关性进行了分析。初步分析了造成各样品之间总有机碳水平差异的原因。结果表明,只以打草场作为利用方式的土壤总有机碳含量较常年放牧场的总有机碳含量高。从草原类型和土壤类型上看,草甸草原总有机碳含量明显高于典型草原,黑钙土总有机碳含量明显高于栗钙土。综上,过度放牧会使草原土壤总有机碳大量释放。总有机碳含量与有机质含量有显著正相关性,相关系数达到0.902。  相似文献   

14.
Six treatments of eastern Kansas tallgrass prairie – native prairie, hayed, mowed, grazed, burned and untreated – were studied to examine the biophysical effects of land management practices on grasslands. On each treatment, measurements of plant biomass, leaf area index, plant cover, leaf moisture and soil moisture were collected. In addition, measurements were taken of the Normalized Difference VegetationIndex (NDVI), which is derived from spectral reflectance measurements. Measurements were taken in mid-June, mid-July and late summer of 1990 and 1991. Multivariate analysis of variance was used to determine whether there were differences in the set of variables among treatments and years. Follow-up tests included univariate t-tests to determine whichvariables were contributing to any significant difference. Results showed a significant difference (p < 0.0005) among treatments in the composite of parameters during each of the months sampled. In most treatment types, there was asignificant difference between years within each month. The univariate tests showed, however, that only some variables, primarily soil moisture, were contributing to this difference. We conclude that biomass and % plant cover show the best potential to serve as long-term indicators of grassland condition as they generally were sensitive to effects ofdifferent land management practices but not to yearlychange in weather conditions. NDVI was insensitive to precipitation differences between years in July for most treatments, but was not in the native prairie. Choice of sampling time is important for these parameters to serve effectively as indicators.  相似文献   

15.
Inter-annual dynamics of grassland yield of the Three Rivers Headwaters Region of Qinghai–Tibet Plateau of China in 1988–2005 was analyzed using the GLO-PEM model, and the herbage supply function was evaluated. The results indicate that while grassland yield in the region showed marked inter-annual fluctuation there was a trend of increased yield over the 18 years of the study. This increase was especially marked for Alpine Desert and Alpine Steppe and in the west of the region. The inter-annual coefficient of variation of productivity increased from the east to the west of the region and from Marsh, Alpine Meadow, Alpine Steppe, Temperate Steppe to Alpine Desert grasslands. Climate change, particularly increased temperatures in the region during the study period, is suggested to be the main cause of increased grassland yield. However, reduced grazing pressure and changes to the seasonal pattern of grazing could also have influenced the grassland yield trend. These findings indicate the importance of understanding the function of the grassland ecosystems in the region and the effect of climate change on them especially in regard to their use to supply forage for animal production. Reduction of grazing pressure, especially during winter, is indicated to be critical for the restoration and sustainable use of grassland ecosystems in the region.  相似文献   

16.
An attempt is made to estimate to what extent it is possible to increase food production by conversion of forest land to agricultural land. To accomplish this two different approaches have been explored. The first one represents the possibility of developing a comprehensive model capable of taking into account the various processes influencing the food production. It is judged that this approach cannot provide a realistic result due to insufficient knowledge of the processes involved, and lack of reliable data. Instead a simple, heuristic method has been applied. The main sources of information used include data representing the soil of the deforested land, the decline of the productivity of the land gained, and the length of time it can be used for agricultural production. Although this method also has its obvious limitations, there are reasons to believe it permits certain conclusions can be safely drawn: (a) even if each year the area of agricultural land is increased by a given amount through removal of forest, there will be no gain of the agricultural production after a few years; and (b) to achieve a constant annual increase of the food production will require that each year the area of forest removal is increased. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

17.
The pristine waters of Kashmir Himalaya are showing signs of deterioration due to multiple reasons. This study researches the causes of deteriorating water quality in the Lidder River, one of the main tributaries of Jhelum River in Kashmir Himalaya. The land use and land cover of the Lidder catchment were generated using multi-spectral, bi-seasonal IRS LISS III (October 2005 and May 2006) satellite data to identify the extent of agriculture and horticulture lands that are the main non-point sources of pollution at the catchment scale. A total of 12 water quality parameters were analyzed over a period of 1 year. Water sampling was done at eight different sampling sites, each with a varied topography and distinct land use/land cover, along the length of Lidder River. It was observed that water quality deteriorated during the months of June–August that coincides with the peak tourist flow and maximal agricultural/horticultural activity. Total phosphorus, orthophosphate phosphorus, nitrate nitrogen, and ammoniacal nitrogen showed higher concentration in the months of July and August, while the concentration of dissolved oxygen decreased in the same period, resulting in deterioration in water quality. Moreover, tourism influx in the Lidder Valley shows a drastic increase through the years, and particularly, the number of tourists visiting the valley has increased in the summer months from June to September, which is also responsible for deteriorating the water quality of Lidder River. In addition to this, the extensive use of fertilizers and pesticides in the agriculture and horticulture lands during the growing season (June–August) is also responsible for the deteriorating water quality of Lidder River.  相似文献   

18.
在遥感与地理信息系统技术支持下,以兵团2000、2005、2010年3期TM影像和HJ1A-CCD1影像为主要数据源,研究了兵团景观空间格局变化特征。结果表明,兵团景观类型从2000—2010年发生了较大变化,农田和城镇面积显著增加,草地、灌丛和冰川(永久积雪)显著减少。城镇景观受人为活动干扰强度最大。分析认为,人口和农业机械化是影响农田景观的主要驱动因素,经济发展和小城镇建设是影响城镇景观格局的主要因素,而政策导向是调节兵团景观格局变化的有效途径。  相似文献   

19.
Offshore wind farm developments may impact protected marine mammal populations, requiring appropriate assessment under the EU Habitats Directive. We describe a framework developed to assess population level impacts of disturbance from piling noise on a protected harbour seal population in the vicinity of proposed wind farm developments in NE Scotland. Spatial patterns of seal distribution and received noise levels are integrated with available data on the potential impacts of noise to predict how many individuals are displaced or experience auditory injury. Expert judgement is used to link these impacts to changes in vital rates and applied to population models that compare population changes under baseline and construction scenarios over a 25 year period. We use published data and hypothetical piling scenarios to illustrate how the assessment framework has been used to support environmental assessments, explore the sensitivity of the framework to key assumptions, and discuss its potential application to other populations of marine mammals.  相似文献   

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