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971.
The confusion effect describes the observed decrease in the likelihood that a predator will successfully catch any prey when
attacking larger groups of moving prey. We introduce readers to the work of cognitive psychologists interested in human visual
attention who have been studying their own version of the confusion effect for many years, developing methods and concepts
that may be of fundamental utility to behavioral ecologists. In psychology, ‘basic features’ are characteristics unique to
a target object in the visual field that no distracter objects share. Images containing targets with basic features are often
less likely to induce the confusion effect in human subjects. Target objects with conjunctions of features, on the other hand,
have no individual characteristics unique from distracters, but unique characteristics in combination. Such targets more often induce the confusion effect in humans. We propose the ‘basic feature’ (vs. conjunctions of features)
as a new organizing concept for studies on the occurrence of the confusion effect in nature, potentially allowing predictions
about which types of prey groups are likely to induce the confusion effect in predators. 相似文献
972.
以人本园林、生态园林、科技园林、艺术园林、文化园林为规划设计的基本原则,采用就地势之高低、造山环水抱之形;专类园与原生态园相辅以丰富景观与植物多样性;引入科普知识和文化内涵以求景、情、意的完美;实现自然美与建筑美的有机结合而营造出最佳人居环境.图5,参8. 相似文献
973.
闸坝河流河道内生态需水研究——以淮河为例 总被引:3,自引:0,他引:3
提出了一种估算闸坝下游河道内生态需水的方法--改进的生态水力半径法(AdaptedEcologicalHydraulicRadiusApproach,AEHRA),该法能够同时计算输出相应河段的生态水位,方便对闸坝进行调度。将其应用到淮河,以鱼类作为生态保护目标,估算了上、中、下游共4个典型闸坝下游河段的生态需水和生态水位,结果表明:①鱼类产卵期内需要较大的生态流量,其顺序为:蚌埠>周口>颍上>白龟山,下游大于上游,中游居中,受断面影响显著;非产卵期则为:周口>颍上>蚌埠>白龟山,中游大于上下游,受河流鱼种影响较大。周口闸下河段全年各月生态需水量相同,需加强上游闸坝的联合调度满足冬季12~-月的生态需水;②要维持河道内生态流量,需进行闸坝调度调整下游水位,保证生态水位;③淮河受人类活动影响剧烈,河流的连续性被切断,生态需水变化没有连续性,只有根据最小生态水位通过闸坝调度,维持河道生态系统最小生态需水,才能逐步恢复淮河健康生态。 相似文献
974.
The people inhabiting the mountains of the Central Himalayan region of India are heavily dependent on their immediate natural resources for their survival. However, this resource-poor mountain ecosystem is gradually becoming unable to provide a minimum standard of living to its continually growing population. In this ecosystem, human population is doubling every 27–30 years, against the declining resource base, particularly forests. Forest are disappearing both quantitatively and qualitatively. Against the requirement of 18 ha of forest land to maintain production in 1 ha of cultivated land, the ratio of forests to cultivated land is only 1.33: 1. The present production from grasslands supports 8 units of livestock, against the ideal 2 units, and the gap between the demand and deficit of fodder is more than 5-fold. Loss of vegetative cover is resulting in drying up of water resources, compelling the women to walk longer distances to collect water. This ecological deterioration, apart from human growth and interference, is compounded by mountain specificities such as inaccessibility, fragility, marginality, diversity, niche and adaptability. The specificities manifest in isolation, distance, poor communication, limited mobility, etc., resulting in limited external linkages and replication of external experiences, and slow pace of development. They, therefore, restrict options for economic growth, effecting poverty and affecting the quality of life of the people of the region. Poverty, in this mountain ecosystem cannot be understood and assessed independent of ecological wealth and would better be termed as ecological poverty. The development efforts to be effective in alleviating poverty here, should take into account mountain specificities and incorporate options which have larger human dimensions, such as mechanisms for population control, socio-economic and cultural conditioning, indigenous knowledge systems of the local people and simple technologies that are already in practice or have potential and are based on least external inputs. 相似文献
975.
As an important tool for environment management, eco-efficiency has been widely applied, but eco-effectiveness has only made progress on eco-design and life cycle management in recent years. Few have attempted to integrate eco-efficiency and eco-effectiveness into sustainable industrial systems. In a new framework integrating eco-efficiency and eco-effectiveness, both concepts can find unique roles and complement each other in industrial ecosystems to dissolve conflicts between industry and the environment. This article provides a case study of China in which eco-efficiency indicators (energy, water and waste utilisation intensity) have demonstrated great progress in China, but eco-efficiency cannot stop the increasing release of pollutants and their accumulating impact on ecological life-support systems. China must integrate eco-effectiveness and eco-efficiency into concrete sustainable development strategies, questioning whether limited resources are being used correctly. Both eco-efficiency and eco-effectiveness are identified as important indicators in the development of sustainable industrial systems. In the framework of sustainable industrial systems, eco-effectiveness must begin to play a more important role. 相似文献
976.
ABSTRACTThis study deploys the livelihoods theory in political ecology together with integrated methods including remote sensing, participatory geographic information systems, interviews and focus group discussions to explore the intricate and dynamic linkages between perennial wildfires and household food insecurity among smallholder farmers in the northern savannah zone of Ghana. Our results suggest that wildfires are a major pathway to household food insecurity in two ways, as perceived by the farmers. First, in instances where wildfires destroy the major crops of smallholders, they are unable to find enough food for the lean season which results in transitory food insecurity. Secondly, in the long term, the environmental impacts of wildfires on the soil lead to lower yields and inadequate food to meet household nutritional needs. Farmers then deploy certain strategies such as early-harvesting and switching to early-maturing crops to avoid with the perennial fires and these strategies further reinforce other dimensions of food insecurity such as nutrition insecurity. Because livelihoods strategies such as crop farming, hunting, charcoal production and herding intersect in the northern savannah zone, we recommend policy options that will engage community members in finding common ways of using shared spaces sustainably. Government should also adopt policies that will encourage domestication of certain livelihood strategies such as cattle herding. 相似文献
977.
为了了解冀北山地退化植被--绣线菊(Spiraea pubescens)灌丛的生态恢复潜力,采用种子萌发法对其可萌发土壤种子库进行了研究,并与其他群落类型进行了比较。结果表明,绣线菊灌丛种子库的种子密度为4 013.33 粒/m2,低于华北落叶松(Larix gmelinii)人工林(4 646.67 粒/m2),但高于榛子(Corylus heterophylla)灌丛(1 713.33 粒/m2)和天然次生白桦(Betula platyphylla)林(746.67 粒/m2);绣线菊灌丛土壤种子库以草本植物为主,没有发现乔木和灌木种子。各群落类型土壤种子库的种子密度有随土壤深度的增加以及坡位的上升而下降的趋势。绣线菊灌丛土壤种子库的物种组成与其他3 种群落类型具有一定的相似性,但低于其他三种群落之间的相似程度。由此得出结论,绣线菊灌丛具有数量庞大的草本植物种子库,群落草本层恢复潜力巨大,但木本植物,尤其是乔木较少,这是限制绣线菊灌丛向森林群落演替的主要限制因素,需要通过人工的方法引入乔木树种,加速群落的演替,促进森林植被的恢复。 相似文献
978.
This paper explores the impact of violent conflict in Nepal on the functioning of community forestry user groups (CFUGs), particularly those supported by the Livelihoods and Forestry Programme, funded by the United Kingdom's Department for International Development (DFID). The key questions are: (i) what explains the resilience of CFUGs operating at the time of conflict?; (ii) what institutional arrangements and strategies allowed them to continue working under conflict conditions?; and (iii) what lessons can be drawn for donor‐supported development around the world? The study contributes to other research on the everyday experiences of residents of Nepal living in a period of conflict. It suggests that CFUG resilience was the result of the institutional set up of community forestry and the employment of various tactics by the CFUGs. While the institutional design of community forestry (structure) was very important for resilience, it was the ability of the CFUGs to support and use it effectively that was the determining factor in this regard. 相似文献
979.
从可持续发展战略论四川的生态环境建设 总被引:4,自引:1,他引:3
可持续发展是接受当代全球人口、资源、环境挑战应运而生的新战略思维。四川省严重的环境、资源和人口问题是全国的一个缩影响。实施可持续发展战略是其唯一正确的选择。为此,应该科学地评价四川省的资源,正确认识长江上游生态环境的建设的利益关系,将生态环境建设纳入可持续发展的轨道。 相似文献
980.
从农业生产、农业生态及环境保护等角度,对农药、化肥和农膜三大农资产品在农业生产中的作用及负面效应进行了分析。认为在现代农业生产中的农药、化肥和农膜具有不可替代的作用。在相当长的一段时间内、这些农资产品的应用是不可能摈弃的。但其负面效应也是不可忽视的。尤其是对农业生态环境的影响。应采取一切行之有效的措施消除或消弱其不利影响。 相似文献