集水农业——河南省旱地农业持续发展的战略选择   总被引：1，自引：0，他引：1  

丁圣彦 《地域研究与开发》1997,(Z1)

介绍了旱地农业、集水、集水农业的基本概念和内容，分析了河南省历史上发生的旱灾及导致旱灾的主要因素，阐述了发展集水农业的必要性和可行性，并通过实例分析说明了集水农业在该省的发展前景，提出旱地农业可持续发展的最佳战略选择是集水农业。  相似文献   

A cladoceran-based paleolimnological assessment of the impact of forest harvesting on four lakes from the central interior of British Columbia, Canada   总被引：1，自引：0，他引：1  

Emma L. Bredesen  Darren G. Bos  Kathleen R. Laird  Brian F. Cumming 《Journal of Paleolimnology》2002,28(4):389-402

To investigate the impact of forest harvesting on lake ecosystems, six lakes (four impact, two reference) from central British Columbia, Canada were assessed using cladoceran remains preserved in the lake sediment cores. Two temporal resolutions were analyzed: a decadal scale for the past 70 years, and a high-resolution scale (2 year intervals for ten years before and after harvesting). Three lakes which experienced forestry activity in their watersheds in the early 1960s, and one lake which experienced forestry activityin the mid 1970s, showed subtle but statistically significant changes in cladoceran species composition following forest harvesting (analysis of similarity tests) at the decadal scale, whereas only two of these lakes showed significant changes at the higher resolution. These changes may be due to increased nutrient levels that might be associated with forest harvesting. The two reference lakes, which had not experienced any known large-scale anthropogenic watershed disturbances in the past century, showed no significant shifts in the cladoceran species assemblages at either temporal scale.  相似文献   

伐区采集作业综合效益评价   总被引：17，自引：4，他引：13  

周新年  沈宝贵  游明兴  吴远彬  林海明 《山地学报》2002,20(3):331-337

在计算各伐区作业模式的经济效益指标和定位测定由诸作业造成的土壤肥力和蓄水保土等指标变化量的基础上,采用集对分析法对各伐区作业模式的综合效益（经济效益和生态效益）进行计算和评价,为确定伐区生产工艺提供科学的决策依据。计算结果表明,“皆伐作业－全悬索道集材”是目前伐区采集作业的优化作业模式,但对常绿阔叶林经营的基本方针是保护,生态效益为主,从长远利益考虑,则“择伐作业－人力集材”为最优作业模式。  相似文献   

Indigenous knowledge for natural resource management: a comparative study of Māori in New Zealand and Dusun in Brunei Darussalam     

Rohana Ulluwishewa  Nick Roskruge  Garth Harmsworth  Bantong Antaran 《GeoJournal》2008,73(4):271-284

Indigenous people often exclusively depend on the natural resources available within the ecosystems where they live, and commonly manage their resources sustainably. They have developed, and continue to develop indigenous knowledge systems which encompass sustainable management of natural resources. This study compares indigenous knowledge of natural resource management developed by two different communities in two different environments—Maori in the temperate environment in New Zealand and Dusun in the tropical environment in Brunei Darussalam, and comparatively evaluates the role of indigenous knowledge in sustainable resource management in three categories of knowledge such as spatial and seasonal distribution of natural resources, sustainable harvesting, and habitat management. The comparison reveals that despite the differences in environment and the great geographical distance between the two communities, there are remarkable similarities between the two knowledge systems in concepts, principles, strategies and technologies used in natural resource management.

Rohana UlluwishewaEmail:

  相似文献   

Can traditional harvesting methods for cockles be accommodated in a Special Area of Conservation?     

McLaughlin  Emma; Portig  Alex; Johnson  Mark P. 《ICES Journal of Marine Science》2007,64(2):309-317

  相似文献   

From regulated access to transferable harvesting rights: Policy insights from New Zealand     

Basil MH Sharp 《Marine Policy》1997,21(6):501-517

The dramatic decline in yields from many of the world's fisheries has prompted an assessment of traditional regulatory approaches to management. Transferable harvesting rights provide an alternative institutional structure in fisheries management. This paper has two aims. First, it links outcomes in the fishery with institutional structure. Second, the paper identifies several important institutional variables if a transition is to be made to from command-and-control management to tradeable rights. In particular, the transition phase must deal with the expectations that attach to the status quo structure of rights in the fishery. The paper's empirical content is drawn from New Zealand's experience with the introduction of transferable harvesting rights.  相似文献   

Tracing stable isotope values from meteoric water to groundwater in the southwestern part of the Chad basin     

I. B. Goni 《Hydrogeology Journal》2006,14(5):742-752

The southwestern Chad basin is a semi-arid region with annual rainfall that is generally less than 500 mm and over 2,000 mm of evapotranspiration. Surface water in rivers is seasonal, and therefore groundwater is the perennial source of water supply for domestic and other purposes. Stable isotope has been measured for rainwater, surface water and groundwater samples in this region. The stable isotope data have been used to understand the inter-relationships between the rainwater, surface water, shallow and deep groundwater of this region. This is being used in a qualitative sense to demonstrate present day recharge to the groundwater. Stable isotope in rainwater for the region has an average value of –4‰ δ¹⁸O and –20‰ δ²H. Surface water samples from rivers and Lake Chad fall on the evaporation line of this average value. The Upper Zone aquifer water samples show stable isotope signal with a wide range of values indicating the complex character of the aquifer Zone with three distinguishable units. The wide range of values is attributable to waters from individual unit and/or mixture of waters of different units. The Middle and Lower aquifers Zones’ waters show similar stable isotopes values, probably indicating similarity in timing and/or mechanism of recharge. These are palaeowaters probably recharged under a climate that is different from today. The Upper Zone aquifer is presently being recharged as some of its waters show stable isotope compositions similar to those of average rainfall waters of the region.  相似文献   

城市生态住宅小区分散式雨水人工湿地处理研究   总被引：3，自引：0，他引：3  

刘瑞 《湿地科学与管理》2008,4(1):25-27

以小区为单位的城市雨水分散式收集利用有利于减轻城市洪涝灾害,减小城市排水管网长度和管径,缓解城市供水压力,对改善城市水环境和生态环境具有重要意义。本文提出利用人工湿地处理小区地表径流并回用于城市地下水补给、绿化的思路,论述了城市雨水人工湿地再生处理利用系统中主要工艺的设计计算方法,为缓解城市用水压力提供有效途径。  相似文献   

An octo-generator for energy harvesting based on the piezoelectric effect     

《Applied Ocean Research》2017

A renewable energy harvester using the piezoelectric effect is developed for the ocean tidal and wind flow. The harvester is made of connected driving blades to an octo-generator, which has a rotator with n blades and a stator attached by eight mass-spring-piston-cylinder-piezoelectricity devices. The resonance and force magnification are utilized to increase the power output of the harvester. A corresponding mathematical model is developed to calculate the root mean square of the generated electric power. The simulation results indicate that the generated power is largely enhanced when the near-resonant condition is established. The power increases with increases in the magnetic flux density, the large-to-small diameter ratio of the cylinder, the size of magnetic bar face, and decreases in the gap between two magnetic faces and the size of the piezoelectric bar face. A generated power of 5 kW is realized by the harvester working under an ocean tidal speed, V = 1.75 m/s, and its geometric and material properties of driving length L = 7.5 m, spring constant k_v = 65000 N/m, gap between the two magnets s = 0.0015 m, large to small diameter ratio of the cylinder z = 6, and magnetic flux density Br = 1.45 T.  相似文献   

Impacts of unregulated harvesting on a recovering stock of native oysters (Ostrea edulis)     

D. Smyth  D. Roberts  L. Browne 《Marine pollution bulletin》2009,58(6):916-116

In Strangford Lough, Northern Ireland stocks of Ostrea edulis collapsed in the 1890s and the species was rarely recorded again until 1998 when the wild stock was estimated to be 100,000. The stock increased to 1.2 million in 2003 but declined to 650,000 by 2005. In 2007 the stock exceeded 1 million. The initial recovery of wild stocks is attributed to the combined effects of spawning commercial O. edulis stocks of and larval retention due to local hydrography. The stock decline between 2003 and 2005 is attributed to unregulated harvesting. Significant differences in abundances between sites over this period may be explained by the exploitation of more-readily accessible sites initially and of less accessible sites later. Oysters at sites where there was minimal exploitation probably contributed to widespread recruitment in 2007. Sustainable management of recovering native oyster stocks in Strangford Lough and elsewhere and will be impossible without appropriate legislation and enforcement.  相似文献