Navigating the Complex Trade-Offs of Pesticide Use on Santa Cruz Island,Galapagos     

Megan O’Connor Robinson  Paul Hirsch 《社会与自然资源》2018,31(2):232-245

Pesticide use by farmers on Santa Cruz Island, Galapagos—a perceived adaptation to changing ecological and economic dynamics—has the potential to lead to environmental degradation in an area that is known and valued worldwide for its biodiversity. We survey Santa Cruz farmers to understand motivations for and concerns about pesticide use on the island. Results from farmer surveys are supplemented with interview data to develop the case study of pesticide use on Santa Cruz Island. We then apply a “complex trade-off” framework to explore and navigate the tensions between conservation and livelihoods. We conclude by elaborating the implementation of a participatory certification system, the Participatory Guarantee System, as a possible path for reconciling trade-offs in Santa Cruz, Galapagos.  相似文献   

西南极利文斯顿岛含砾泥岩层的发现及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文

邓希光  郑祥身  刘小汉 《极地研究》1999,11(3):169-178

西南极南设得兰群岛利文斯顿岛赫德半岛中分布的一套主要由复理石相岩石组成的低级变质沉积岩（迈尔斯陡崖组）被认为是中－ 新生代火山岩的基底（晚古生代－ 早中生代？）。以前含砾泥岩在迈尔斯陡崖组局部地点曾有零星报道,但详细的地质填图确认此地有四层含砾泥岩分布。研究表明,这些含砾泥岩可能是水下碎屑流沉积,其生成环境可能是海底扇中扇的水道。对比在南极半岛所发现有大量的含砾泥岩,则进一步表明利文斯顿岛早期地质特征可与南极半岛相比,两者在中－ 新生代岩浆弧形成之前处于相同的构造环境。  相似文献   

海坛岛海域表层沉积物中主量化学成分的地球化学   总被引：1，自引：0，他引：1  

杨慧辉  陈岚 《海洋学报》1998,20(3):47-55

本文对海坛岛海域３３个表层沉积物中１０种化学成分的含量、含量变化和区域平面分布作了描述和探讨。化学成分中Ｃｏｒｇ、Ｎ、Ｐ、Ｆｅ、ＡＩ、Ｔｉ、Ｍｇ等元素的关性好,和粘土矿物关系密切,从陆源搬运入海;Ｃａ、碳酸盐和上述及粘土含量呈负相关,在富含生物介壳的粗粒沉积中富集;Ｍｎ主要赋存于陆源碎屑,而在砾砂中有自生Ｍｎ沉积。Ｑ型聚类分析的结果表明,调查区可分为３个地球化学分区,综合反映了沉积物的地球化学特征。  相似文献   

琼东沿岸上升流二维数值模型的诊断计算   总被引：8，自引：3，他引：5  

郭飞  侍茂崇  夏综万 《海洋学报》1998,20(6):109-116

我国沿岸有两大上升流区域,其一在浙江沿岸.迄今为止,对其形成机制、时空变异等,已经进行了较多的定性及定量研究.  相似文献   

海南岛表土花粉和热带植被模拟研究   总被引：10，自引：0，他引：10  

于革  韩辉友 《海洋地质与第四纪地质》1998,18(3):103-112

调查分析了海南岛各种热带植被下的表土花粉,并根据花粉数据进行植被类型的模拟。结果表明,表土花粉类型复杂,优势种不明显,反映了热带植被下的植物种类繁多复杂的特性。分模拟能够较好地反映热带气候下的雨林,季雨林和干草原植被,其地理位置与地区植被的地理分布基本一致,海南岛山地的花粉模拟还恢复了热带山地植被,而海岸红树林植被能够被海岸带的花粉证据所模拟。该研究能够为我国大范围表土花粉调查和热带植被类型提供花  相似文献   

Lichens as bioindicators in volcanic areas: Mt. Etna and Vulcano Island (Italy)     

M. F. Grasso  R. Clocchiatti  F. Carrot  C. Deschamps  F. Vurro 《Environmental Geology》1999,37(3):207-217

 The aim of this paper is to verify whether lichens have the capacity to accumulate atmospheric contaminators linked to volcanic activity. About 100 lichens were collected in 1994 and 1995 from two active volcanic areas in Italy: Mount Etna and Vulcano Island. Twenty-seven elements were analyzed for each individual lichen using Instrumental Neutronic Activation Analysis and Inductively Coupled Plasma-Mass Spectrometry. Lichen composition reflects the contribution of the volcanic particulate material, and the two areas investigated can be distinguished on the basis of the concentration of some lithophile elements. Moreover, the distribution in lichens of the elements (As, Sb, Br, Pb) – derived from gas emissions (plume, fumaroles) – also shows different geochemical trends on Mt. Etna and Vulcano. Received: 20 April 1998 · Accepted: 4 July 1998  相似文献   

台湾以北海域浮游桡足类生物海洋学特征的研究Ⅱ.群落特征   总被引：10，自引：2，他引：8  

杨关铭  何德华  王春生  苗育田  于洪华 《海洋学报》1999,21(6):72-80

在对台湾以北海域浮游桡足类生物海洋学特征进行数量分布方面的研究后的续篇,重点对本海区浮游挠足类的群落结构和群落性质以及与栖区环境条件间的关系作了分析探讨．结果表明,本区桡足类群落结构种类组成复杂,出现种类共２３７种,但周年共有种比例仅占３２％．桡足类群落的多样度和均匀度年均值各为３．７１４和０．６９０,在平面分布上呈外部海区高于近岸海区的大体趋势．本区群落可划分为５个生态类群,其中暖水性外海高温偏低盐类群和热带大洋高温高盐类群可分别指示台湾海峡水和黑潮表层水的季节消长过程．从不同侧面的计算分析均表明,冬季在环境条件上均有异于其他３季．在春、夏、秋季,以普通波水蚤最具优势,盐度是影响群落特征值的主导因子,群落的性质是以暖水性外海种类为主、热带大洋种也占相当比例的亚热带－热带群落结构的特点;在冬季,主要优势种是海洋真刺水蚤,温度是群落特征值的主要制约因子,群落呈现以热带大洋种占支配地位的热带大洋群落结构属性．  相似文献   

Structure of Réunion Island (Indian Ocean) inferred from the interpretation of gravity anomalies     

Barbara Malengreau  Jean-Franois Lnat  Jean-Luc Froger 《Journal of Volcanology and Geothermal Research》1999,88(3):347

Réunion is a volcanic edifice whose origin is related to a hot spot in the Indian Ocean. Only 3% of its volume is emergent. Many geological and geophysical studies were carried out on Réunion Island during the 1980's but few of them allow study of the internal structure of the edifice. Several gravity surveys have been carried out on the island since 1976 and we have compiled the available data set. The lack of data on the western side of the island led us to conduct a regional survey in 1993 to obtain a more homogeneous distribution of the stations. Computation of Bouguer anomalies for different correction densities accounts for the variable density of the rocks constituting the edifice and provides a distribution of gravity anomalies interpreted as dense bodies of intrusive rocks inside the edifice. Two very large intrusive complexes can be unambiguously recognised: one beneath Piton des Neiges and one beneath the Grand Brûlé area. Both have been penetrated by geothermal exploration drill holes and the first is also known from outcrop observations. 2.5D simple models were constructed to reveal the geometry and extent of the buried intrusives. They are deeply rooted, extending several kilometres below sea level, and extensive (20–25 km long and 10–13 km wide for the Piton des Neiges complex, 12–15 km long and some kilometres wide for the Grand Brûlé complex). The development of such complexes implies that the activity of the two volcanic centres was long lasting and remained stable while the volcanoes were growing. The Grand Brûlé complex has been interpreted as relics of an old volcano named Alizés Volcano. The interpretation of the gravity maps suggests the presence of a ridge of dense rocks to the North of the axis joining the centres of Piton des Neiges and Piton de la Fournaise volcanoes. By analogy with the other structures, 2.5D models show that this structure would culminate between 0 and 1 km below sea level and be 15 km wide. This complex induces a maximum anomaly in Takamaka Valley and we thus propose to name it Takamaka Volcano. No geological evidence of the nature of these dense rocks is available but the ridge coincides with structures revealed by magnetic and seismic data. Interpretation of the Bouguer anomaly maps suggests that the inner gravity structure of Piton de la Fournaise is not characterised by the presence of a voluminous dense body but probably by more restricted concentrations of dense rocks. Some structures can be recognised: along the present NE and SE rift zones and in the previous central part of Piton de la Fournaise to the West of the present summit. The recent eastward migration of the centre of activity of Piton de la Fournaise accounts for the lack of a large positive anomaly beneath the active craters.  相似文献   

Geochemistry of some major chemical composition in marine sediments of the Haitan Island     

Yang Huihui  Chen Lan 《海洋学报(英文版)》1999,18(1):127-135

INTRODUCTIONTheHaitanIslandislocatedalongthecoastinthemiddlesectionofFujianProvince.ItfacestheTaiwanStraitoneast,bordersontheHaitanStraitonwest,andholdsthestrategicpassageoftheFuqingBay.ThegeographicalPOsitionoftheislandissituatedbetween25'33,--25"40'Nand119o41,--119"52'E.Coveringanareaof251.4km2,itisamongthelargestislandsinFujianProvince.BasedondataofacomprehensiveinvestigationintheseaareaoftheHaitanIslandduringMay1990andJune1993,thegeochemicalcharacteristicsofCo,,,N,P,Fe,Al,T…  相似文献   

六横大岙附近海域环境质量现状评价   总被引：1，自引：0，他引：1  

魏琳瑛  卜献卫 《海洋学研究》1999,17(1):66-71

根据１９９５年４月对码头工程区附近海域的水质和沉积物的环境质量现场调查,采用环境质量指数法,评价了该海区水质和沉积物的环境质量状况。结果表明,水质中无机氮严重超标,超三类标准的超标率达１００％。无机磷超一类标准的超标率达１００％,有个别测站超二类标准。ＣＯＤ、ｐＨ、ＤＯ、油类均低于一类海水标准。潮间带水质基本符合一类水质要求。底质环境质量现状良好  相似文献