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1.
2003年至2007年春季,利用鸟类环志方法对洪河自然保护区春季林栖鸟类多样性进行研究。共记录到鸟类8目20科90种4082只,为洪河国家自然保护区记录鸟类种数的42.07%。雀形目鸟类种类和数量均最多,共78种4029只,占鸟类种数的86.67%,鸟类数量的98.70%。利用多样性指数和均匀性指数方法对洪河保护区春季鸟类多样性进行了分析,其多样性指数为3.4015,均匀性指数为0.7559。从年份看,2005年春季鸟类多样指数值为最高,2003年最低;各年度多样性指数为2005(3.2513)2004(3.2506)2007(3.1506)2006(2.9281)2003(2.6718)。均匀性指数则2007年最高,2003年最低;各年度均匀性指数为2007(0.8139)2004(0.8006)2005(0.7787)2006(0.7307)2003(0.7307)。  相似文献   

2.
2012年4月10日-5月15日,在黑龙江珍宝岛国家级自然保护区对春迁徙水类多样性进行了调查,共记录到鸟类7目13科45种99567只次。共记录到国家级重点保护鸟类13种26899只。应用鸟类多样性公式对春季水鸟多样性进行了分析,其多样性指数、均匀性指数和物种丰富度指数分别为1.849641、0.336797、和0.00042。并对水域、沼泽、草甸和农田水鸟多样性进行了比较;结果表明其多样性为水域(1.791485)>沼泽(1.789785)>草甸(1.629579)>农田(0.098193);均匀性指数为草甸(0.701821)>沼泽(0.368422)>水域(0.330151)>农田(0.098193);物种丰富度指数为草甸(0.037313)>农田(0.003175)>沼泽(0.000951)>水域(0.00063。本研究为今后水鸟资源管理和濒危物种的保护提供了科学依据。  相似文献   

3.
内蒙古图牧吉自然保护区春季迁徙水鸟多样性研究   总被引:1,自引:0,他引:1  
2011年4月5日~5月5日,在内蒙古图牧吉国家级自然保护区对春迁徙水类多样性进行了调查,共记录到鸟类7目13科45种99567只次。共记录到国家级重点保护鸟类13种26899只。应用鸟类多样性公式对春季水鸟多样性进行了分析,其多样性指数、均匀性指数和物种丰富度指数分别为1.849641、0.336797、和0.00042。并对水域、沼泽、草甸和农田水鸟多样性进行了比较;结果表明其多样性为水域(1.791485)>沼泽(1.789785)>草甸(1.629579)>农田(0.098193);均匀性指数为草原(0.701821)>沼泽(0.368422)>水域(0.330151)>农田(0.098193);物种丰富度指数为草原(0.037313)>农田(0.003175)>沼泽(0.000951)>水域(0.00063)。本研究为今后水鸟资源管理和濒危物种的保护提供了科学依据。  相似文献   

4.
洪河自然保护区春秋季鸟类多样性比较研究   总被引:5,自引:0,他引:5  
对洪河自然保护区春秋两季不同生境类型(林地,灌丛,草甸)的鸟类多样性进行了统计和分析,其鸟类多样性春委较秋委突出,3种生境中,草甸的鸟类最为多样性,灌丛次之,林地最差。  相似文献   

5.
2003和2004年春、秋两季鸟类迁徙期时,对洪河国家级自然保护区境内迁飞鸟类进行网捕环志,并对其种类及数量进行了相关分析。2年间共网捕环志迁徙鸟95种6072只,隶属6目20科。其中春季78种3011只,秋季81种3061只。春季以燕雀、灰头和田为迁徙鸟类的优势种,每种各环志728、548、403只;秋季以燕雀和灰头的数量占绝对优势,各环志619和542只。对网捕迁徙鸟类进行多样性分析发现:2003年春季迁徙鸟类Shannon-Weaner指数和Pielou均匀度指数最高,H’=3.96;J=0.70。从两年内迁徙鸟类总体看,G指数为3.37,F指数为22.62,DG-F=0.85。这表明该地迁徙鸟类在种、属、科等分类阶元的多样性均较丰富。  相似文献   

6.
黑龙江七星河春季白枕鹤觅食生境初步研究   总被引:2,自引:0,他引:2  
白枕鹤(Grus vipio)为大型涉禽,由于栖息地丧失,数量减少,已被CITES列为附录I,IUCN红皮书列为全球濒危物种,并被列为国家II级重点保护鸟类;2011年4-5月,笔者在七星河自然保护区对白枕鹤春季觅食地生境进行了调查;采用GPS定位技术和直接观察法对白枕鹤栖息生境进行测定,共获取70个1m×1m的样方,利用样方法和因子测定法测定其春季觅食地植物的类型、高度、盖度、植物密度、水深、人为干扰距离等。结果显示:白枕鹤春季主要在以苔草、小叶章为主的沼泽湿地中觅食;最佳觅食地植被高度为40-80cm,植被密度高于600株/m2,植被盖度为0-25%,觅食地水深多为5-15cm,人为干扰距离大于2000m;人为活动严影响着白枕鹤的觅食;春季白枕鹤有在火烧地中觅食的现象。  相似文献   

7.
本研究以三江平原湿地典型草甸小叶章群落为研究对象,从物种丰富度、均匀度和物种多样性指数等方面探讨其季节动态规律.典型草甸小叶章群落物种丰富度在7月份最高,生态优势度指数季节动态变化呈“V”型;多样性信息指数季节动态变化呈单峰型,6月末7月初群落群落的物种多样性最高,种类之间个体分配的均匀性最大;均匀度指数季节动态变化呈线型.群落α多样性的测度指标的季节动态变化表现出一致性.  相似文献   

8.
库尔滨自然保护区地处小兴安岭北坡山麓末端,黑龙江省逊克县东南部。笃斯主要分布于由玄武岩及第四纪堆积物而复盖成的草甸土和沼泽土及草甸化沼泽土之中。 本区植物属于长白植物区系,植被区划为小兴安岭—老爷岭植物区中小兴安岭—张广才岭亚区(森林)和穆陵—三江平原亚区的过渡地段,为森林草甸草原区。经过3年多实际调查及636块标准地的样查研究,保护区内有579种植物,隶属于89科,296属,529种,1亚种,42变种,7变型。 按着黑龙江省植被分区的划分,自然保护区是属于温带针阔混交林区域,小兴安岭红松针阔混交林地区的次生林型中有6个植物群落,森林草甸类型中有3个植物群落。  相似文献   

9.
洪河湿地夏季丹顶鹤觅食生境初步研究   总被引:1,自引:0,他引:1  
丹顶鹤(Grus japonensis)为大型涉禽,由于栖息地丧失,数量减少,已被CITES列为附录I,IUCN红皮书列为全球濒危物种,并被列为国家I级重点保护鸟类;2012年6月,笔者在洪河自然保护区对丹顶鹤夏季觅食地生境进行了调查;共获取80个1m×1m的样方,利用样方法和因子测定法测定其夏季觅食地植物的类型、高度、盖度、植物密度、水深、人为干扰距离等。结果显示:丹顶鹤夏季主要在以苔草、小叶章为主的沼泽湿地中觅食;最佳觅食地植被高度为40~80cm,植被密度400~800株/m2,植被盖度为25%,觅食地水深多为10~15cm,人为干扰距离为0.4~0.8km;人为活动严重影响着丹顶鹤夏季的觅食。  相似文献   

10.
基于大连市土地利用空间数据,选用斑块数、斑块分离度、景观多样性指数、优势度指数、均匀度指数、生态环境指数等景观特征指数,从斑块和景观两个尺度对大连市土地利用空间格局进行定量评价,揭示其对区域生态环境的影响。结果表明:(1)旱地景观是大连地区面积最大、分布最广、连续性最强的基质景观;其次,林地景观的面积比例也较大;水田、草地和水域的面积比例较小。(2)城乡用地景观的斑块数最多,其次为林地;旱地景观斑块分离度最小,为0.03其次为林地景观,为0.08;沼泽景观的斑块分离度最大,为2.06。(3)大连市的生态环境指数为0.43,与辽宁沿海其他城市相比较,其生态环境质量的总体状况较好,但仍有提升空间。  相似文献   

11.
This paper introduces contributions to a symposium that report some of the findings and arguments to emerge from a collaborative research project involving five Colombian universities forming the Observatorio de Restitución y Regulación de Derechos de Propiedad Agraria (Observatory of Restitution and Regulation of Agrarian Property Rights). In a number of ways, the research presented in the symposium advances understanding of the political economy of rural Colombia, and of war in Colombia, and the papers, drawing on the original evidence collected by Observatorio researchers, develop arguments that have a wider relevance too for agrarian political economy and the understanding of violent conflict. In particular, the papers highlight the direct participation of elites in violent conflict; the varieties and nuances of wartime primitive accumulation; the complexities of the state's role in wartime agrarian political economy; the gender dimensions of agrarian conflict; the interaction of war and law; and the significance for service provision of farm size. As Colombia—hopefully—passes from long war to peace, these arguments and this evidence may be valuable in debates about what kind of peace can develop.  相似文献   

12.
Supermarkets, wholesalers, and tomato growers in Guatemala   总被引:3,自引:0,他引:3  
The article shows the asset‐related determinants and the impacts of the participation of small farmers in supermarkets versus traditional market channels in Guatemala. Compared to farmers selling only to the traditional market channels, farmers selling to supermarket channels are larger (but are in the upper tier of the “small farmer” category), have more capital, and are much more specialized in commercial horticulture in general and in tomatoes in particular. While they have higher yields, they also have higher input use, including use of chemicals. In fact, they severely overuse pesticides and fungicides. Moreover, these greater input expenditures mean that their profit rates are roughly similar to those of farmers in the traditional market channel. Supermarket‐channel farmers prefer the more demanding wholesale‐supermarket channel because it offers lower risks and lower transaction costs to market, a variety of quality grades of tomatoes, all year long. In turn, the supermarkets, who do not buy direct but rather source from a few specialized‐dedicated wholesalers, rely on this year‐round supply, lower transaction costs, and consistency of quality.  相似文献   

13.
Information and communications technologies (ICTs) have spread rapidly in the developing world. There has been considerable interest in the potential role ICTs, particularly mobile phones, have begun to play in the marketing of agricultural outputs in these countries. In this article, we discuss the potential impacts ICTs may have on welfare, both in terms of potential efficiency gains (via improved arbitrage), and welfare transfers among agents in the supply chain (via reduced informational asymmetries and market power). We also review the recent empirical evidence for such effects.  相似文献   

14.
The article explores the relationship between fertilizer use and the demand for weather index insurance (WII) among smallholder farmers in Ethiopia. We examine whether fertilizer use is profitable under current smallholder production conditions, whether risk‐related factors affect fertilizer use, and we estimate the returns to inputs in the agricultural production function in the absence of insurance. We then study how these primitives of agricultural production functions relate to insurance demand. The study compares a survey‐based estimate of willingness to pay with actual uptake for the weather insurance, finding the stated and actual demand to be almost completely uncorrelated. While those with high marginal returns to inputs say they would purchase insurance, only those with low marginal returns actually do, consistent with the stated purpose of the product as input insurance. Insurance demand proves to be highly responsive to the existence and amount of randomly allocated insurance vouchers.  相似文献   

15.
16.
Increased investment in agricultural research could contribute to sustainable development goals and benefit farmers, consumers, the environment, and the economy. This paper provides recent evidence and a critical assessment of the evolving Canadian canola crop development and innovation policy and compares it to the wheat and pulse sectors that differ in degree of biotechnology adoption, seeded acreage, intellectual property rights, and private sector involvement. This study also assesses how crop characteristics and technological changes affect future optimal public policy. A number of innovation policies are discussed that could stimulate further growth within the crop sector.  相似文献   

17.
The hydropower potential of the state of Uttarakhand, in the Indian Himalaya, is an estimated 20,000 MW, of which approximately 3200 MW have been developed. In conjunction with the central government, Uttarakhand is pursuing a policy of rapidly developing its remaining potential. The necessity for careful planning, assessment and mitigation of this development is paramount, requiring meaningful and effective public participation. This study examined two hydropower projects in Chamoli District. Our purpose was to investigate how stakeholders viewed the projects’ impacts, how local residents were involved in planning, assessment and mitigation, and what the residents learned from their involvement. We used a qualitative methodology involving a document review, participant observation, and semi-directed interviews. Local residents and nongovernmental organizations emphasized adverse social and environmental impacts. They thought the way of life and social fabric of affected villages were significantly altered and future sustainability was uncertain. Industry respondents emphasized the economic benefits. Government officials were relatively balanced in their perceptions. In one project, the only formal participation opportunity occurred during mitigation: development of the catchment area treatment plan. In the other, opportunities were available during assessment (e.g., hearings) and mitigation (e.g., advisory committees). Both projects involved multiple informal efforts at participation (e.g., legal petitions and public protests). Among local residents, there were notable instances of sustainability-oriented learning. The development of hydropower projects in Uttarakhand can become more participative, to improve decision making, promote equity, and create opportunities for sustainability learning.  相似文献   

18.
Women play an important role in the agricultural production process in developing countries, yet their role in making decisions about what to grow and implications for household welfare remains poorly understood. In this article, I study women's empowerment in northern Mozambique as it relates to agriculture, considering in particular the factors associated with women managing the plots that they nominally control. Women control about 30% of the plots in the data, but only manage about 70% of those plots. Using a unique panel data set, I find that women are more likely to manage plots when households have had historic access to off‐farm labor, typically completed by men. When women manage plots, they tend to grow crops with less complicated production techniques and are less likely to grow the main area cash crop. However, conditional on historic access to off‐farm labor their farm incomes are the same as among men.  相似文献   

19.
This article examines the role of institutional services of credit, input supply, and extension in the overall commercial transformation process of smallholder agriculture in Ethiopia. Survey data collected in 2006 from 309 sample households in three districts of Ethiopia are used for the analyses. Tobit regression models are used to measure the effect of access to services on the intensity of inputs use for fertilizer and agrochemicals. A probit model is used to measure these effects on the adoption of improved seeds. Intensity of use of seeds is analyzed using an ordinary least squares model. Logarithmic Cobb–Douglass functions are estimated to analyze the effect of access to services on crop productivity. Heckman's two‐stage estimation is used to examine determinants of household market participation and the extents of participation. Results show that access to institutional support services plays a significant role in enhancing smallholder productivity and market orientation. Our results imply that expanding and strengthening the institutional services is critical for the intensification and market orientation of smallholder agriculture in Ethiopia. In particular, appropriate incentives and regulatory systems are urgently needed to encourage the involvement of the private sector in the provision of agricultural services.  相似文献   

20.
The growth of smallholder tobacco production since 2000 has been one of the big stories of Zimbabwe's post–land reform experience. Yet the implications for agrarian change, and the consequences for new relations between farmers, the state, and agribusiness capital have rarely been discussed. The paper reports on work carried out in the Mvurwi area of Mazowe district in Zimbabwe with a sample of 220 A1 (smallholder) farmers and 100 former farmworkers resident in compounds on the same farms. By going beyond a focus on operational and business dimensions of contract farming, the paper concludes with reflections on the implications for understanding agrarian relations and social differentiation in those areas of Zimbabwe where tobacco growing is now significant, with lessons more broadly on the political economy of contract farming, and the integration of agribusiness capital following land reform.  相似文献   

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