黑龙江珍宝岛自然保护区春季迁徙水鸟多样性研究

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。     

黑龙江小北湖保护区春季鸟类多样性研究

2015年春季,利用样线法和样点法对小北湖自然保护区春季鸟类多样性进行研究。共记录到鸟类16目40科148种4904只,为小北湖国家级自然保护区记录鸟类种数的58.04%。雀形目鸟类种类和数量均最多,共68种3470只,占鸟类种数的45.95%,鸟类数量的70.76%。利用多样性指数和均匀性指数方法对小北湖保护区春季鸟类多样性进行了分析,其多样性指数为3.8877,均匀性指数为0.4575。从生境上分析,林地生境鸟类多样指数值为最高,水域生境最低;不同生境多样性比较:林地(3.3191)草甸(3.1073)灌丛(2.9531)沼泽(2.7129)水域(2.1868);均匀性指数则草甸生境最高,水域生境最低;均匀性比较:草甸(0.4592)沼泽(0.4543)灌丛(0.4465)林地(0.4417)水域(0.3484)。     

三江平原湿地典型草甸小叶章群落物种多样性的季节动态

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.     

洪河国家级自然保护区春季林栖鸟类多样性研究

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)。     

封育措施对呼伦贝尔草甸草原区草地生产力的影响

目的 研究围封条件下植物群落中物种变化的分布特征,有助于解释退化草地在不同围封阶段演替规律。方法 文章以温性草甸草原为研究对象,采用野外定位随机采样方法,调查群落生物量、植物物种种类、密度、盖度及高度,探讨时间尺度封育状态下的温性草甸草原植物群落特征、物种多样性的变化。结果 （1）封育措施显著增加了群落盖度,比围栏外的自由放牧样地提高了13.79%~114.75%,且随着封育年限的增加群落盖度表现出先增加后降低;而封育措施对群落密度没有显著性影响。（2）封育显著增加了植被地上生物量、地下生物量以及禾草生物量,其中地上生物量较围栏外的自由放牧样地提高了66%~887.3%,禾草生物量和地上生物量均随着封育年限的增加表现出先增加—降低—增加—降低的波动变化,地下生物量在监测年份下表现为先增加后降低的变化;封育措施可以提升植物多样性,随着封育年限的增加,多样性指数和丰富度指数呈现先增加后降低的变化趋势。结论 封育措施可以显著提高草地生产力,并且对物种多样性也有一定的促进作用,是应对退化温性草甸草原恢复的有效措施,但退化草地在长期围封后,应进行适度利用来维持较高的生产力。     

呼伦贝尔草甸草原不同放牧强度下植被特征分析

该文利用草地的野外实测数据,计算了物种综合优势比、物种丰富度、物种多样性及其群落高度、盖度、密度、地上生物量等数量指标,对两种草甸草原样地三种放牧强度的群落结构和功能指标进行了研究。结果表明:从物种水平分析,羊草草甸草原样地(LM)和贝加尔针茅草甸草原样地(SM)的建群种的综合优势比随放牧强度加大而下降,而退化标志物种,如寸草苔、糙隐子草及冷蒿等呈上升趋势。从群落水平分析,LM样地比SM样地物种多样性维持能力弱,耐牧性弱。     

呼伦贝尔草甸草原退耕后不同恢复期植物多样性变化

[目的]通过揭示开垦草原退耕后不同恢复期的植物多样性变化,旨在为呼伦贝尔草甸草原管理和恢复受损草地生态系统提供理论依据。[方法]文章以呼伦贝尔草甸草原为研究对象,运用样方调查和室内分析,对不同退耕年限退耕地与对照的天然草地的植被特征进行同步调查,并借助单变量一般线性模型对退耕地和天然草地的植被特征,分物种重要值,植物多样性指数及响应比等进行差异性分析,研究了开垦草原退耕后不同恢复期的植物多样性变化。[结果]退耕5年、13年和17年的样地植物丰富度和植物多样性指数均显著小于对照的天然草地,而退耕19年的样地的丰富度和多样性指数与对照天然草地无显著差异;相较于退耕5年的退耕地,在退耕时间更长的退耕地中,植物群落主要层片由菊科植物转变为禾本科植物。退耕地群落演替过程中,随退耕年限增加,与天然草地间差异性减小,逐渐接近天然草地。[结论]退耕是一种有效地促使植物多样性接近天然草地的措施。且除退耕年限外,退耕地与天然草地间群落相似程度同时受天然草地初始状况影响。     

黑龙江洪河国家级自然保护区迁徙鸟类多样性研究

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。     

三江平原地区杂类草沼泽植物群系α多样性特征

通过对三江平原地区杂类草沼泽的调查,初步确定了15个群系类型,并运用α多样性指数即常用的丰富度指数、均匀度指数和物种多样性指数3个指数来测度各群系的多样性特征。     

东洞庭湖湿地野生鸟类资源调查研究

根据在东洞庭湖湿地实地实时调查,共鉴定鸟类2 172只,合计23种,隶属6目14科;东洋界鸟类7种,古北界鸟类1种,广布种鸟类15种,在区系上以东洋界鸟类为主;冬候鸟、留鸟分别为16种、7种,在居留型上,主要以冬候鸟居多。该区鸟类平均密度为158.9只/hm2,多样性指数为2.426467,均匀性指数为0.773871。多年来由于自然因素以及人类不合理的开发利用活动,东洞庭湖湿地野生鸟类资源面临许多生态威胁;指出了东洞庭湖湿地野生鸟类资源面临的生态问题,并提出了相应的保护对策。     

Information,efficiency, and welfare in agricultural markets

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.     

Supermarkets, wholesalers, and tomato growers in Guatemala

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.     

Productivity,credit, risk,and the demand for weather index insurance in smallholder agriculture in Ethiopia

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.     

Introduction: Land rights,restitution, politics,and war in Colombia

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.     

Crop research,biotech canola,and innovation policy in Canada: Challenges,opportunities, and evolution

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.     

Gender,control, and crop choice in northern Mozambique

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.     

Smallholders,institutional services,and commercial transformation in Ethiopia

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.     

Values,trust, and management in New Zealand agriculture

This study provides empirical evidence of the link between outlook and practice among farmers, foresters, and growers in New Zealand. Specifically, we use a large, nationally representative survey to assess how foci on production and environmental outcomes influence the adoption of six good management practices aimed at increasing agricultural sustainability. We then show that while environmentally oriented and production-oriented decision-makers are statistically more prepared to take risks, all rural decision-makers are more likely to adopt new technologies and good practices after seeing their relative advantages successfully demonstrated. Next, we show that social and professional networks are small, often limited to five or fewer operators, which begs the question about how the risk-averse operators become informed about good practice. Hence, we ultimately analyse trust in order to identify other credible demonstrators or informants. We find that veterinarians are the most trusted source of information and that government (at all levels) is the least.     

Tobacco,contract farming,and agrarian change in Zimbabwe

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.