Effects of pollinator density-dependent preferences on field margin visitations in the midst of agricultural monocultures: A modelling approach

Managed field margins offer a means of reducing the impact of agricultural monocultures within intensively managed environments. By providing refuge for wild plants and the pollinators associated with them, field margins can also contribute to enhancing the pollination services within the monoculture. However, the effects of the monoculture on pollinator behaviour need to be carefully considered. It is known that pollinators may show density-dependent preferences such as neophobia (an avoidance of unfamiliar items) when different types of flower are available within their environment, and the dominance of monoculture crops within the environment may consequently have adverse effects upon the preferences shown by pollinators living in the field margins within them. In order to examine how pollinator preferences for wild flowers are affected by monocultures, we modelled the effects of density-dependent preferences, flower densities, and the geometry of field margins within a monoculture landscape using numerical simulations. This was done by considering how the placement of pollinator nests within a simple, spatially explicit landscape consisting of fields of monoculture crops separated by margins containing wild flowers affected the ratio of wild and monoculture crops experienced by the pollinator, given that it could only forage within a limited distance from its nest. Increasing field margin width and decreasing monoculture field width both led to an increase in pollinators visiting wild flowers (which levelled off as width increased). The size of the monoculture fields had little additional effect once they had passed an intermediate width. Increasing wild flower density within the margins led to a shift away from preferring monocultures. When wild flowers were at low densities compared to the monoculture, even the addition of small amounts of extra wild flowers had a large effect in shifting foraging preferences away from the monoculture. The distance which pollinators normally forage over only has an effect upon preferences for wild flowers when the travel distance is small. This suggests that careful consideration of margin design might be extremely important for those species which do not travel far. Innate preferences for density-dependence and particular crop types may also have an effect on preference behaviour. We demonstrate that the way in which resources are presented to indigenous pollinators may be extremely important in influencing where they choose to forage within agricultural landscapes. Careful margin design, as well as increasing the density of wild flowers (such as by enhancing the wild seed bank within the margins), may lead to overall improvements in ecosystem function within intensively farmed monocultures.     

我国现代农业发展路线与发展战略

在当前,我国现代农业发展背负着重大包袱,面临着日益激烈的国际竞争,大力发展现代农业成为迫切需要.世界农业形势出现了新的变化,集中体现在理念创新、科技创新和制度创新.结合我围发展现代农业的国情,构建一个以产业理念创新为核心,以科技创新为动力,以组织保障制度创新为支撑的现代农业发展战略框架,描绘一个30年跨度的我国农业发展路线图,具有积极的理论意义与现实意义.     

Multiscale Methodological Framework to Derive Criteria and Indicators for Sustainability Evaluation of Peasant Natural Resource Management Systems

Design and implementation of more sustainable natural resource management systems is the current objective of many research institutions, development agencies, NGOs and other stakeholders. But, how to assess whether a system is sustainable? How do we know whether the alternatives designed will increase the sustainability of the system? How to evaluate or assess the sustainability of natural resource management systems?In this paper we present a multiscale methodological framework for sustainability evaluation. The framework is based on a systems approach from which five general attributes of sustainable natural resource management systems are defined based on scale- and discipline-independent properties (productivity, stability, resilience, reliability and adaptability).A general operational strategy to derive ‘site-specific’ criteria and indicators for the attributes at different scales is also presented. This strategy is based on the definition of ‘impact scales’, at which the different stakeholders can or want to design alternatives, as well as the main stakeholders’ objectives and constraints. The application of the multiscale framework is illustrated with a case study in the Purhepecha Region of Michoacán, a peasant mountainous region in the west of Mexico. We used stakeholder consultation to identify the main objectives and constraints as well as to select criteria and indicators. The sets of criteria and indicators suggested for the different scales of analysis of the Purhepecha Region are comprehensive, yet not exhaustive, and represent the main issues related to natural resource management in the region. Further work will be directed towards the quantification of indicators at different scales and their relationships and trade-offs.     

Risk communication, value judgments, and the public-policy maker relationship in a climate of public sensitivity toward animals: revisiting britain's foot and mouth crisis

This paper offers some suggestions on, and encouragement for, how to be better at risk communication in times of agricultural crisis. During the foot and mouth epizootic, the British public, having no precedent to deal with such a rapid and widespread epizootic, no existing rules or conventions, and no social or political consensus, was forced to confront the facts of a perceived "economic disease. Foot and mouth appeared as an economic disease because the major push to eradicate it was motivated exclusively by trade and economic reasons and not because of threats it posed to the lives of human beings and livestock. The British public deferred responsibility to their elected officials for a speedy end to this non-life threatening viral epizootic. The latter, however, did not have a contingency plan in place to tackle such an extensive outbreak. The appeal to an existing policy, i.e., mass eradication, as the exclusive strategy of containment was a difficult pill for the public to swallow well before the end of the 226-day ordeal. Public outcry reflected (in part) serious misgivings about the lack of effective communication of risk-informed decisions between government agents and all concerned. The government's handling of the matter underestimated concerns and values about animal welfare, public trust, and the plight of farmers and rural communities. A general loss of trust by some segments of the public was exacerbated by perceived mismanagement and early fumbles by government agents.Public moral uneasiness during the crisis, while perhaps symbolic of growing discontent with an already fractured relationship with farmed animals and the state of animal farming today, arguably, also reflected deep disappointment in government agents to recognize inherently and conditionally normative assumptions in their argument as well as recognize their narrow conception of risk. Furthermore, broader stakeholder participation was clearly missing from the outset, especially with respect to the issue of vaccination. A greater appreciation for two-way risk communication is suggested for science-based public policy in agriculture, followed by suggestions on how to be more vigilant in the future.     

Environmental management in resource-rich Alberta, Canada: first world jurisdiction, Third World analogue?

Economic growth is frequently touted as a cure for environmental ills, particularly for those in Third World countries. Here we examine that paradigm in a case study of Alberta, Canada, a wealthy, resource-rich province within a wealthy nation. Through provincial-scale datasets, we examine the increasing pressures of the forest, petroleum, and agricultural industries upon the ecosystems of Alberta within management, economic, and political contexts. We advance the thesis that economic activity leads to environmental degradation unless ecosystem-based management is integrated into economic decision making. Agricultural lands cover 31.7%, and forest management areas leased to industry cover 33.4% of Alberta; both continue to increase in extent. The rate of logging (focused on old-growth by government policy) continues a decades-long exponential rise. Current Alberta annual petroleum production is 52.5 million m3 crude oil and 117 billion m3 of gas. As of early 1999, there were approximately 199,025 oil and gas wells and a conservative total of approximately 1.5-1.8 million km of seismic lines in Alberta. Fire occurrence data indicate no downward trends in annual area burned by wildfire, which may be characterized as driven by climate and inherently variable. When logging and wildfire are combined, the annual allowable cut in Alberta is unsustainable, even when only timber supply is considered and the effects of expanding agriculture and oil and gas activities are ignored. Ecosystem degradation in Alberta is pervasive and contrasts prominently with a high standard of living. A wealth of ecological data exists that indicates current resource-based economic activities are non-sustainable and destructive of ecosystem health yet these data are not considered within the economic decision making process. Given the complex, compounded, and increasing ecosystem perturbations, a future of unpleasant ecological surprises is likely. We conclude with tentative predictions as to where current trends in Alberta may lead if decisions biased against ecosystems continue.     

Formation of Rodent Communities in Arable Lands of Northern Eurasia

Rodent communities of crop fields have been demonstrated to fundamentally differ from rodent communities of natural biotopes. Communities dominated by Microtus arvaliss. lato, Mus musculus, and Apodemus agrariusoccupy the largest areas of arable fields in northern Eurasia. These are typical agrophiles. They usually rapidly colonize various crop fields, inhabit them seasonally or throughout the year, and successfully reproduce there, losing their connections with natural biotopes. Agriculture helps a few agrophilic species to flourish but reduces the general diversity of rodents.     

中国可持续农业和农村发展试验示范区的建设

资源相对短缺、环境污染、农业生态环境总体形势较为严峻和人口不断增加等是制约我国农业与农村可持续发展的主要限制因子。为探索一条适合我国国情的农业与农村持续发展的道路，“八五”期间，结合不同地区的生态类型和经济特征，在全国29个地、县进行了农业与农村可持续发展的示范区建设。本文介绍了试验示范区建设的内容及特点。     

有机农业与中国传统农业的比较

介绍了有机农业的起源与内涵，比较了有机农业与中国传统农业的联系与区别，并提出了促进我国有机农业发展的建议     

复合农林业的由来与兴起

由于人口的增长,人们对粮食、烧柴的需求与日俱增,致使森林面积减少,土壤等自然资源退化,生态环境恶化。对此于20世纪70年代提出了“复合农林业(Agroforestry)”,并发展成一门新兴的学科。它有意识地将多年生木本植物与农作物或家畜结合起来,在为农村提供烧柴、木材、饲料、粮食的同时,又可保持土壤肥力,达到持久农业的目的。它对我国大面积山丘地区自然资源的综合利用与保护有着重要的意义。     

菱塘养鱼技术研究

报导了“菱塘养殖”的某些关键技术。它们包括：（１）通过品种结构调整，解决鱼菱相克的矛盾；（２）通过在菱群落“开天窗”，避免鱼窒息致死；（３）实行混合养殖，拓宽生态位；（４）通过鱼种投放量与鱼产量关系的研究，为鱼种合理搭配提供了科学依据。由于上述问题的解决，这种农业模式发挥了明显的经济效益。