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1.
Ozone is an unusual trace gas in the atmosphere, presenting a challenge for risk assessors and risk managers. The challenge can be traced to the gas’ complex chemistry in the atmosphere (exposure), toxicology in biological systems (response), and the fledgling enterprise of risk assessment for widely distributed, highly reactive pollutants. This paper addresses the (i) co-evolution of the scientific data underlying ozone risk assessment on human health, natural resources (crops and managed forests), and unmanaged ecosystems, (ii) similarities and differences in risk assessment among these receptors, and (iii) utility of indicators in risk assessment. The scientific community has developed a sound database to underpin the ozone risk assessment, although the breadth and depth differ markedly among the three receptors. There are similarities in ozone risk assessment among human health, natural resources, and ecology, including features of exposure (e.g., temporal variation), response of plants and humans (e.g., sensitive cohorts), and integration of exposure and response (e.g., importance of peak and cumulative exposures). Equally important are the notable differences, and the more prominent are scaling of exposure-response relationships, air quality monitoring, economic valuation, and models to complement more traditional experimental approaches. Of the three receptors, the status of indicators for conducting ecological ozone risk assessment is the weakest.  相似文献   

2.
Yunnan is well known as a "Kingdom of Plant". Yunnan is also rich in natural resources of crop. Lots of studies on collection, conservation, protection, evaluation and utilization of crop genetic resources have been done in recent years. But there are some unfavourable factors, too. With the agricultural intensity, some new problem such as decreasing diversity, simplifying varieties and narrowing genetic basis of crop have arisen to restrict the development of agriculture in Yunnan. The only way to achieve a sustainable agriculture in Yunnan is doing our utmost to protect the crop diversity, develop new crop or new varieties and widen the genetic basis of crop varieties.  相似文献   

3.
开发立体农业,可以充分发挥土地、光能、热量、水源等自然资源的潜力;可以充分利用空间和时间,通过间套混、铺挂架等立体种植和层养、混养等立体养殖,较大幅度提高单  相似文献   

4.
"云南及周边地区生物资源调查"项目于2006-2011年,对云南省31个县、四川省8个县和西藏自治区2个县的农业生物资源进行了系统调查。系统调查的41个县的地形、地貌十分多样,气候类型很多,有"一山有四季,十里不同天"的说法。加之,这些县份都集居有少数民族,少数民族有各自的传统文化和生活习俗,从而赋予了农业生物资源丰富的民族文化内涵。正因为这里的多样性气候和各异的民族文化,造就了丰富的农业生物资源。通过调查获得了大量基础数据和信息,收集到5300多份农业生物种质资源,其中有一批稀有种质资源,这些稀有种质资源对相应农业生物的起源进化和系统分类研究,以及新品种选育都具有重要利用价值。  相似文献   

5.
Humanity is facing possibly the greatest challenge in its history. Population is expected to reach 9 billion in 2030. At the same time agricultural land is becoming scarcer and poorer in quality. Furthermore, the environmental impact of intensive agriculture and the effects of climate change are threatening food security in many regions of the globe. Further, shortage of fossil fuels will have dramatic effects on the performance of intensive agriculture. There is an urge to develop more ecological agricultural practices both to meet the need to preserve agroecosystems health and to deal with the reduced availability of “cheap” energy from fossil fuels. This paper reviews a number of studies comparing the performances of conventional and organic agriculture in light of energy use, CO 2 emission and other environmental issues. Organic agriculture, along with other low input agriculture practices, results in less energy demand compared to intensive agriculture and could represent a means to improve energy savings and CO2 abatement if adopted on a large scale. At the same time it can provide a number of important environmental and social services, such as preserving and improving soil quality, increasing carbon sink, minimizing water use, preserving biodiversity, halting the use of harmful chemicals, thereby guaranteeing healthy food to consumers. We claim that more work should be done in terms of research and investment to explore the potential of organic farming for reducing environmental impact of agricultural practices. However, in the case of organic agriculture, the implications of a reduced productivity for the socioeconomic system should be considered and suitable agricultural policies worked out.  相似文献   

6.
Recent studies suggest that wild agave (Agavespp.) plants in Sonora, Mexico, are being over-harvested by mescal makers on communal lands. Using the conceptual framework of regional political ecology (Blaikie and Brookfield, 1987), I discuss the ecological processes of agave depletion, and investigate the social, economic, and political contexts in which unsustainable harvest practices arise. Whereas all the mescal makers have knowledge of sustainable harvest methods, population growth, expansion of agriculture onto ecologically marginal lands, and increasing dependence on wild harvested products from communal lands created the socioeconomic context for increased demand for mescal income. The ideology of household autonomy, and the belief that the village has no right to internally regulate use of the commons, created the political context for rapid, unsustainable harvesting—a tragedy of the commons. However, recent cultural changes have caused a reversal of this trend, and some wild agave populations may be recovering.  相似文献   

7.
云南及周边地区少数民族对农业生物资源的保护与利用   总被引:1,自引:0,他引:1  
"云南及周边地区生物资源调查"项目属于国家科技部基础性工作专项。云南及周边地区是我国少数民族聚集区,农业生物多样性十分丰富。然而,近些年来随着经济发展,外来文化的渗透,该地区正经历着较大的变迁,少数民族文化和农业生物资源正在逐步消失[1]。为了保护和发扬少数民族的传统文化和农业生物资源,对该地区的41个县和10个民族进行了系统调查。本次调查全面完成了各项任务和考核指标。本文仅介绍云南及周边地区少数民族对农业生物资源的保护和利用情况,旨在为国家保护和发扬少数民族传统文化,制定生物资源保护政策和科学研究提供基础信息和科学依据。  相似文献   

8.
世界粮食和农业植物遗传资源保护与利用现状   总被引:8,自引:3,他引:5  
本文根据联合国粮农组织2010年发布的<第二份世界粮食和农业植物遗传资源现状报告>[1]及相关资料,综述了全球粮食和农业植物遗传资源保护和发展现状,内容包括种质多样性概况、原生境保护、非原生境保护、评价与利用、国家计划与管理、国际和地区合作、获取与利益分享以及对粮食安全和可持续农业的贡献.文章最后分析了我国存在的差距,提出了加强粮食和农业植物遗传资源保护和发展的建议.本文数据较新,内容齐全,是资源管理者、保护者和利用者的重要参考材料.  相似文献   

9.
Parenting behavior may respond flexibly to environmental risk to help prepare children for the environment they can expect to face as adults. In hazardous environments where child outcomes are unpredictable, unresponsive parenting could be adaptive. Child development associated with parenting practices, in turn, may influence cultural patterns related to insecurity and aggression (which we call the "risk-response model"). We test these propositions in a cross-cultural analysis. The Standard Cross-Cultural Sample (SCCS) includes indicators of parental responsiveness: father–infant sleeping proximity, father involvement, parental response to infant crying, and breastfeeding duration (age at weaning). Unresponsive parenting was associated with cultural models including greater acceptance of extramarital sex, aggression, theft, and witchcraft. Socialization practices in later childhood were not better predictors of the outcomes than was earlier parenting. We conclude that some cultural adaptations appear rooted in parenting practices that affect child development.  相似文献   

10.
简要叙述了《粮食和农业植物遗传资源国际条约》的目标和内容以及自生效以来取得的新进展,包括供资战略的实施、履约进展、方便获得和利益分享多边系统建设以及促进履约的计划和措施等,以期为我国植物遗传资源工作者和政府有关部门提供参考。  相似文献   

11.
大青山外生菌根真菌资源与生态研究   总被引:5,自引:0,他引:5  
白淑兰  刘勇  周晶  董智  樊荣 《生态学报》2006,26(3):837-841
历经5a,采用踏查与样线调查相结合的方法,对内蒙古大青山主要林区的外生菌根真菌资源与生态进行了系统研究。通过对子实体鉴定及对菌根组织的分离与回接研究,并借鉴前人对大青山大型真菌调查资料,初步认为在大青山分布的外生菌根真菌共163种,占现有国内报道种的26.6%,它们分别隶属于18科、41属。在大青山此次调查发现内蒙新记录种54种,占大青山记录种的33%,还有5个存疑种;通过对分布区内各生态因子研究表明,在大青山外生菌根真菌喜欢生长在有机质丰富、林分郁闭度0.7~0.9、海拔1300~1900 m、阴坡的中部、坡度为20~40°的环境中,而在陡坡、山顶或山麓分布较少;通过对生境土壤理化因子分析结果表明,菌根真菌的存在能够明显降低土壤pH值、并对环境中全N含量有显著的提高,对全P、全K无显著影响,但对速效态N、P、K释放均有显著的促进作用,尤其速效K的释放与对照存在着极显著的差异;从对共生关系研究表明,白蘑科(Tricholomataceae)、红菇科(Russulaceae)、丝膜菌科(Cortinariaceae)、鹅膏科(Amanitaceae)的大部分真菌,以白桦(Betula platyphyllaSuks.)、山杨(Populus davidianaDode.)、云杉(Picea asperataMast.)、蒙古栎[Quercus mongolica(Fisch.)Turcz.]、虎榛子(OstryopsisdavidianaDecne.)为主要宿主,而牛肝菌科(Boletaceae)的大部分真菌主要以油松(Pinus tabulaeformisCarr.)、华北落叶松(Larixprincipisr-upprechtiiMayr.)、云杉、白桦、虎榛子等为主要宿主植物。  相似文献   

12.
Anthropologists have described, but seldom explained, the existence and persistence of common pool resource systems among hunting and gathering populations. Land tenure practices in the Fort Irwin area of the Mojave desert, California are explored. Ecological, ethnographic, archeological, and ethnohistoric information suggests that this area was jointly owned and intermittently used by several distinct ethnic groups. Although the region was important as a buffer against resource shortfall during certain seasons, sporadic use and meager and variable resource yield may have made exclusive ownership difficult and costly. A jointly managed region with common pool resources better served surrounding groups, while simultaneously creating a spatial buffer to diffuse social tensions. Following presentation of the Fort Irwin case, the paper considers the formation of such land tenure practices among hunting and gathering populations.  相似文献   

13.
Shifting cultivation has traditionally been characterized as a highly productive system in terms of the ratio of energy outputs to inputs. This characterization, however, does not take into account the energy contribution of the natural vegetation cleared in preparing the field for cultivation. As a result, the central feature of shifting cultivation, the exploitation of the natural vegetationsoil complex as a substitute for human labor, has been ignored. The omission of the biomass contribution can be attributed to both a focus on the practices involved rather than the underlying strategy of the shifting cultivator, and an excessive preoccupation with the renewability of the energy sources involved in different agricultural systems. A definition of shifting cultivation is proposed that focuses attention on the relationship between the natural vegetationsoil complex and the shifting cultivator. Two methods of including the energy contribution of forest biomass in calculating the productivity of shifting cultivation systems are compared. When the biomass contribution is included, shifting cultivation appears to be an extremely unproductive system of agriculture.I would like to thank Bill Denevan, Chris Uhl, Christine Padoch, Tom Klak, Bob Buschbacher, and Mimi Kranichfeld for their comments on earlier versions of this paper.  相似文献   

14.
15.
青海柴达木盆地气候生态资源特点和农业开发   总被引:2,自引:0,他引:2  
柴达木盆地位于青海高原西北部,面积为2.5×10~5km~2,海拔3000m,周围山系海拔5400—6000m,较毗邻新疆塔里木盆地高2000m 左右,为我国海拔最高的内陆高原盆地。有可利用草场约6.67×10~6ha。耕地约6.0×10~4ha,作物主要为春小麦,分布于东南和东北部荒漠绿  相似文献   

16.
Over a 4 month period, systematic and ad libitum observations were conducted on two adult female black-and-white ruffed lemurs (Varecia variegata variegata) and their infants in a 3.5 ha forest enclosure. The females were mother and daughter, members of a family group that had been semifree-ranging for 2 years and 3 months at the time of the births. One to two weeks before parturition, the females independently constructed nests, in which they kept their infants during the first few weeks following parturition. The older mother, cage-reared herself, prepared at least one nest. Her daughter, who has lived in the forest since late juvenescence, prepared at least four. Two to three weeks after parturition, the mothers moved their infants high into trees. During periods of maternal absence, the infants were often alone, and they rarely or never moved, vocalized, or groomed themselves. The mothers often kept their infants together after nests were no longer used. Each infant nursed freely from both lactating females. The infants were carried orally only by their mothers and were never transported by clinging to the pelage of any group members. Previously, researchers suggested that ruffed lemurs build nests for care of infants high up in trees. The present observations, however, suggest that two major modes of neonate care in Varecia exist: serial use of multiple ground nests and “parking” of infants high in trees. Advance preparation of several nest sites, relative lack of large predators, alternate maternal and paternal guarding of infants, infant immobility during absence of mother, and rapid infant development make this tactic of care for neonates plausible.  相似文献   

17.
中国普通菜豆种质资源朊蛋白变异及多样性分析   总被引:1,自引:0,他引:1  
朊蛋白是研究普通菜豆遗传多样性的一种重要且有效的生化标记。本试验通过SDS-PAEG凝胶电泳检测中国普通菜豆种质资源的朊蛋白变异类型,分析中国普通菜豆种质资源的遗传多样性及组成特点。来自中国13个省(自治区)的445份供试材料共检测到S、Sb、Sd、B、C、CA、T、PA、To、H、H1、CH 12种朊蛋白类型,表明中国普通菜豆种质朊蛋白变异类型丰富,遗传多样性水平较高。其中,Sb型朊蛋白种质最多,占比29.0%;T型其次,占比28.1%。依据朊蛋白类型在不同基因库的特异性,将研究材料明显地区分为中美基因库和安第斯基因库两大类。研究还发现中国普通菜豆种质资源中地方种质朊蛋白类型变异丰富,多样性明显高于现代育成品种或品系。最后,对种质朊蛋白类型与百粒重、子粒颜色、粒型进行相关性分析,结果表明朊蛋白类型与百粒重呈极显著正相关,而朊蛋白类型与子粒颜色、粒型2个性状之间无明显相关性。本研究结果将为普通菜豆种质资源的保护及有效地挖掘优质种质资源提供理论依据。  相似文献   

18.
A large and growing number of agricultural households in less developed countries are also engaged in international migration. Thousands of farmers from the highland provinces of Cañar and Azuay, Ecuador, have immigrated to metropolitan New York, where they work in menial jobs and remit, as a group, millions of dollars annually. This paper examines the effects of international migration on agricultural production and land-use in two regions of Cañar Province. An agricultural survey was administered in two communities to determine land-use and agricultural production of migrant and nonmigrant households. Contrary to most reports on the subject, migration has neither led to agricultural abandonment nor have remittances been dedicated to agricultural improvements. Semisubsistence agriculture remains an important riskaverse economic and cultural activity, but cultivation is a poor investment. A large investment in housing and land has converted much of the region into a peri-urban landscape of cultivated real estate.  相似文献   

19.
As a result of increasingly apparent and problematic effects of global information system and remote sensing technologies, there has been increased emphasis on demonstrating and incorporating indigenous environmental knowledges in land use and cover analysis. Such approaches, though ethnographically revealing and politically efficacious, tend to reproduce a model of difference between local and scientific knowledges that is epistemologically untenable. This paper demonstrates an alternative use of geographic information system and remotely sensed imagery to both demonstrate the partiality of mapping technology and show possibilities for critical usage of the tool. Using a case from India, the research shows a method to elicit and explore competing environmental knowledges, including and especially those of scientific experts. The analysis concludes that, for both local producers and expert managers, the cultural meaning of landscapes is dependent on their roles in regional production and resource politics.  相似文献   

20.
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