Cropland expansion and grassland loss in the eastern Dakotas: New insights from a farm-level survey

The western Corn Belt region of the United States has become a hotspot for agricultural extensification and consequent land use and land cover changes. The goals of this research were to characterize geographic patterns of grassland loss resulting from cropland expansion in the eastern Dakotas, and to understand how these changes were associated with characteristics of individual farms and farm operators. We collected data on grassland conversion and other land use decisions through a mail survey of farm operators in North and South Dakota. Overall, 40% of respondents converted at least some grassland to cropland between 2004 and 2014, and the total acreage of converted grassland was equivalent to 5.1% of the surveyed farm acreage. Although most converted grassland acres (3.2% of farm acreage) were from land enrolled in the conservation reserve program (CRP), there were also substantial amounts of native grassland conversion (1.0%) and tame grassland conversion (0.9%). The total acreage of grassland conversion was more than four times larger than the acreage enrolled in CRP and other conservation programs. Different types of grassland conversion (e.g., native grassland versus CRP) were concentrated in different parts of the study region, and were spatially disjunct from the areas of highest conservation program enrollment. Larger farms were more likely than smaller farms to expand their cropland acreage and accounted for a disproportionate share of grassland conversion. Younger farm operators, higher levels of farm income, higher proportions of rented croplands, and marginal yields were also associated with cropland expansion and grassland conversion. Although CRP and other land retirement programs will remain important policy mechanisms for conservation in this region, they are not sufficient to maintain current levels of grassland cover and do not provide protection for native grasslands. Alternative conservation strategies and new agricultural policies are thus critically needed to maintain the ecosystem services provided by grasslands.     

不同利用方式下草地CH4、CO2及N2O通量研究

[目的]在全球气候变化背景下,研究天然草地和人工草地的温室气体通量以及与部分环境因子的相关关系,进而明确不同草地对温室气体通量的影响情况,为当地相关部门合理开发利用草地提供理论依据,推进草业绿色发展、高质量发展。[方法]文章以内蒙古自治区的阿鲁科尔沁旗选取退化的天然牧草地、混播型放牧人工草地以及刈割型人工牧草地为研究对象,利用目前较为普遍的箱法进行了野外实验,对比分析不同草地利用类型的主要温室气体CO₂、CH₄和N₂O的通量变化情况,并进一步探讨了温室气体与土壤含水量、箱内温度、地表温度以及其他土壤养分指标的相关性。[结果](1)不同利用方式下草地的CO₂通量在整个生长季均表现为排放,其中刈割人工草地的CO₂排放量为67.00±9.15 mg/(m²·h),显著高于放牧人工草地35.50±5.37 mg/(m²·h)和天然草地30.17±4.57 mg/(m²·h)(P<0.05),且CO₂     

草原资源的合理开发利用

从农业可持续发展的需要出发，通过对黑龙江省草原资源的现状、草原利用过程中存在的问题和问题产生的原因的分析，提出合理开发利用草原资源的建议。     

昂昂溪考古文化初论

昂昂溪文化是含细石器的新石器文化,它以渔猎经济为主,晚期有农业经济出现,是具有显著特点的区域性文化。它自成体系,独立发展,并不是其它文化的延伸和传播所产生的附属文化。虽然目前还没有形成系统的研究工程,但三十多年来不断发现的各类文化遗址、遗物点迭四百多处,从类型和数量上足以说明“昂昂溪文化”是嫩江流域文化的重要环节,是中华民族古代文明的重要组成部分。     

我国退耕还林产品形态及战略拓展

对中外退耕还林情况进行了概述,并从产品经济学角度出发,描述我国退耕还林工程产品的两种形态:即大范围自然生态区,国家买单;小范围局部生态经济圈,市场买单。同时提出4点建议:建立退耕土地银行制;完善有效的国家和个人利益平衡关系;加强退耕还林区非农人口输出和就业扶持;加强特色经济的多方位扶持和产业键延伸。     

Local participation in cultural landscape maintenance: Lessons from Sweden

Local participation has evolved as a strategy in the conservation and maintenance of biological and cultural values in cultural landscapes. The meaning(s) of the concept, however, are fuzzy, and conditions for fruitful implementation have only been investigated to a limited extent. In this article, a couple of Swedish cases serve as points of departure for a better understanding of the prerequisites and critical aspects as regards an increased local involvement in landscape management. A review of research on community participation reveals some essential aspects; power relations, participants, the institutional framework, organisation, communication, knowledge building, monitoring and contextual factors. These aspects have formed the structure for the analysis of two cases within which local involvement is considered successful; Southern Öland, where community involvement in seminatural grassland management has been experienced in LIFE-projects and in the process of becoming a UNESCO World heritage site, and Mälarhagar, an integrated restoration and beef production project carried out in close collaboration with farmers. The results are discussed in terms of successful ingredients, counterproductive aspects and operational difficulties. The findings show that trust, communication and local influence are vital ingredients in a participatory approach. Communication and co-management are pointed out as central areas of competence for executives working with landscape management and planning. There are, however, collisions between directives concerning nature conservation and directives concerning public participation. For successful local involvement, the subject for collaboration has to be broadly defined. Furthermore, the strong emphasis on collaboration in participatory approaches demands that democratic aspects have to be considered.     

Evidence of climate change impacts on crop comparative advantage and land use

Relative agricultural productivity shocks emerging from climate change will alter regional cropland use. Land allocations are sensitive to crop profits that in turn depend on yield effects induced by changes in climate and technology. We develop and apply an integrated framework to assess the impact of climate change on agricultural productivity and land use for the U.S. Northern Great Plains. Crop-specific yield–weather models reveal crop comparative advantage due to differential yield impacts of weather across the region's major crops, that is, alfalfa, wheat, soybeans, and maize. We define crop profits as a function of the weather-driven yields, which are then used to model land use allocation decisions. This ultimately allows us to simulate the impact of climate change under the RCP4.5 emissions scenario on land allocated to the region's major crops as well as to grass/pasture. Upon removing the trends effects in yields, climate change is projected to lower yields by 33–64% over 2031–2055 relative to 1981–2005, with soybean being the least and alfalfa the most affected crops. Yield projections applied to the land use model at present-day input costs and output prices reveals that Dakotas’ grass acreage will increase by up to 23%, displacing croplands. Wheat acreage is expected to increase by up to 54% in select southeastern counties of North Dakota and South Dakota, where maize/soy acreage had increased by up to 58% during 1995–2016.     

A Meta-analysis of the Willingness to Pay for Cultural Services from Grasslands in Europe

We investigate the willingness to pay (WTP) for cultural ecosystem services from grasslands using a meta-analysis based on 32 eligible research papers that provide in total 79 estimates. The average WTP (corrected for purchasing power) across these studies is 38 Euros per person per year. Yet, our analysis reveals that the transfer of these results needs careful evaluation. More specifically, it is essential to frame the monetary valuation exercise in relation to the direction of grassland change. A switch from cropland to grassland reduces WTP by 90 Euros while an increase in less-intensive land-use in mountain regions raises WTP by 53 Euros. We conclude that for an adequate consideration of grasslands in holistic ecosystem services assessments, the direction of grassland change is important.     

生态视角下的内蒙古绒山羊生产规模分析

羊绒业是内蒙古的一大特色产业，同时也是内蒙古少数在国际市场上拥有较大影响力的产业之一。但随着内蒙古羊绒业总产值的增加，厂商数目不断增加，规模不断扩张的同时，其原料——山羊绒的供给问题越来越凸显出来。一方面是对羊绒原料需求的增加派生出山羊养殖的增加，但另一方面却是山羊养殖的增加对生态环境带来严重影响。文章从内蒙古绒山羊生产规模的现状分析入手，研究内蒙古绒山羊生产规模扩大的后果。重点分析了绒山羊养殖的增加对生态环境的影响，并估计出内蒙古草原对山羊的承载能力和羊绒最大产量。为内蒙古绒山羊生产规模的发展提出建议。     

基于季节性因素的草原生态旅游可持续发展探析  ———以内蒙古为例

草原生态旅游发展中存在诸多问题和制约因素,其中季节性便是显著问题。内蒙古是草原生态旅游的典型区域,其旅游淡旺季对比十分明显,旅游季节性已经是一个制约内蒙古旅游可持续性发展的关键因素。本文对其成因及影响分析提出解决策略,即要立足实际突出自身特色发展内蒙古草原生态旅游业,而且需要人们转变淡季思维定式和旅游思维观念对解决草原生态旅游的季节性问题有很大帮助。