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91.
《Marine Policy》2017
Socio-economic development of small-island fishing communities is greatly dependent on local coastal and marine resources. However, illegal fishing and aggressive practices in insular ecosystems lead to over-exploitation and environmental deterioration. Moreover, a lack of scientific data increases uncertainty and prevents the adequate monitoring of marine resources. This paper focuses on the integration of local fishing communities into decision-making processes with the aim of promoting artisanal fishing on the Island of Tenerife (the Canary Islands), as a way to preserve the marine ecosystem and socio-economic development of traditional cofradias (fishers' organisations). A qualitative methodological framework, based on participatory problem-solution trees and focus groups, was used to identify the main factors impeding the sustainable development of the artisanal fishing sector on the island and to elaborate collective proposals with policy implications. The fishing community involved identified four main issues that are maintaining an unsustainable island fishery: 1) Over-exploitation; 2) Poor self-management of cofradias and commercialisation problems; 3) Fisher individualism and low co-management strategies, and 4) Illegal fishing increase vs. artisanal fishing decline. Results show the required policy enhancements to tackle them and the need to adapt regulations to the local situation. 相似文献
92.
《Marine Policy》2017
This article considers corporate power in the fishing industry of southeast Alaska and Puget Sound, Washington State, USA, as experienced by direct marketing salmon gillnet fishermen. Tracing the evolution of a small family-based fish business, this paper examines survival strategies of independent fishermen in a context of concentrated corporate power. Topics addressed include corporate domination of the fishing industry, “niche” alternatives to the commodity system, alliance with the farmers’ market movement, obstacles to direct sales and the critical role of family participation. 相似文献
93.
《Marine Policy》2017
Transition to low carbon sea transport is a logical response to the extreme dependency of the Pacific Islands region on imported fossil fuel, its significant vulnerability to the effects of climate change and the critical shipping needs of Pacific Island countries (PICs). Building on previous work in low carbon sea transport in the Pacific, this paper further considers the barriers to achieving such transition by assessing, through a ‘post-Paris Agreement’ lens, the Intended Nationally Determined Contributions (INDCs) submitted by PICs and contrasting these to the near total lack of investment and planning for low carbon transition in the transport sector with the parallel occurrence in the electricity sector where ~USD 2 billion of donor investment is deployed or queued despite electricity using only ~20% of fossil fuel across the region. Consistent with recent international studies, inadequate and inappropriate financing and policy have been identified as dominant transition barriers for low carbon sea transport development in PICs. This paper further examines the regional level barriers to policy development, and finds them inhibited by the silo nature of the major regional actors. The implications that the Paris Agreement has for climate financing to support the essential research and capacity development needed to underpin a successful low carbon sea transport transition strategy at any useful scale and speed are also considered in this paper. 相似文献
94.
《Limnologica》2016
The ecological integrity of freshwater ecosystems is regularly examined through assessment of their macroinvertebrate assemblages. The various methods used in such biomonitoring all have one characteristic in common – the neglect of water mites. Even though this group perfectly fulfills all necessary requisites for successful bioindicators, these invertebrates are either completely ignored or lumped together as “Acari”.This study, for the first time, uses water mites (Hydrachnidia) as bioindicators in the Neotropics to compare the anthropogenic stress in 15 streams at three different levels of contamination (pristine, rural, urban). In total, 4371 water mite specimens, belonging to 31 genera and 14 families, were collected.Diversity, abundance, and richness of water mite assemblages were significantly reduced with increasing levels of contamination. These differences were clearest in the dry season. Atractidella turned out to be, by far, the most tolerant water mite genus, having the greatest abundance at the most contaminated sites. In contrast, Pseudotorrenticola was found only in pristine waters, while Hydrodroma, Limnesia, Koenikea, Torrenticola, Monatractides and the family Aturidae showed clear preferences for pristine waters.Our data show, that water mites, identified to genus level, are well suited for water quality assessment in neotropical lowland streams, clearly distinguishing different levels of contamination/anthropogenic stress. 相似文献
95.
《Limnologica》2015
Modern ecological assessments of running waters are based on the a priori definition of ecological benchmarks, given by reference-quality sites. Such benchmarks are established at the level of ecoregions, typologies, or site. Yet, in highly disturbed regions, such as coastal areas of European countries, the assessment of streams’ water quality based on the reference condition concept is very difficult, due to the lack of undisturbed sites. Among others, the reduced number of reference sites may have as a consequence the definition of imprecise ecological benchmarks. Here we tested the hypotheses that (1) the increase in the number of potential reference sites (2) the definition of more precise abiotic thresholds using the least disturbed condition approach (LDC), and (3) the use of diatom assemblages, as the most ubiquitous element in lowland areas, would result in refinement and eventual sub-division of existing river types of a highly disturbed area, such as the Portuguese centre-western region. For this purpose, abiotic data characterising natural conditions of 55 sites from a littoral highly disturbed region were used in a hierarchical classification analysis that revealed the existence of three different sub-groups. In addition, a three-step approach was used to define thresholds for the pressure variables in LDC. Based on these new thresholds, sites in LDC were selected. A hierarchical classification performed to the LDC diatom spring assemblages revealed the existence of two sub-groups, concordant with two of the abiotic sub-groups. Several species contributed to the dissimilarity between the two sub-groups (e.g., Achnanthidium minutissimum and Karayevia oblongella). Differences between the sub-groups were also found in the trait proportions of stalked species. New benchmark values for these two sub-groups, based on the scores of the official diatom index, the Indice de Polluosensibilité Spécifique (IPS), were different from the previous reference value used. Yet, no biological benchmark values were established for one of the groups due to the absence of sites in the LDC. Our study suggests that streambed substrate is an important characterisation variable in the river type definition and highlights that, in spite of the potential refinement in reference conditions and typology obtained, an alternative approach that does not require the use of reference sites should be explored in the future. 相似文献
96.
利用CAP 方法快速计算云南地区中小地震震源机制解 总被引:1,自引:1,他引:0
地震的震源机制解是反应区域应力场的重要参数,充分利用数量众多的中小地震将有助于获得更高精度的区域应力场分布。本文以滇西地震预报实验场下关虚拟测震台网为例,介绍了利用虚拟台网产出数据,采用CAP 方法计算中小地震震源机制解的流程,并将该方法应用于计算云南地区2013 年2 月~ 2014 年2 月间MS≥3. 0 的64 次中小地震震源机制解。结果显示:①本文给出的方法为一种半自动处理方法,该方法可以在地震速报结果之后45 分钟之内给出震源机制解,分析认为影响震源机制解快速产出的主要因素是格林函数库的建立和编程实现标注P 波到时的全自动化;②云南地区中小地震震源机制解以走滑为主,但在香格里拉和洱源地区有少量正断层地震存在,位于研究区域内中小地震P 轴主应力方向在川滇菱形块体南部以北北西-南南东为主,而在印支板块则主要以北北东-南南西为主。 相似文献
97.
98.
M. J. Winterbourn 《新西兰海洋与淡水研究杂志》2013,47(3-4):271-281
The invertebrate fauna colonising wooden blocks placed in a beech forest stream was studied over a period of 1 year. At least 31 species were taken during the course of the study, with 3 species of Chironomidae predominating numerically. Most species were associated principally with fine particulate matter (FPM) deposited on the upper surfaces of blocks, although a stonefly, Spaniocerca zelandica, was most abundant on the barer surfaces. Of the Chironomidae, Paucispinig‐era approximata and Polypedilum canum had clearly defined life history patterns with emergence from February to April and October to January, respectively. Psectrocladius sp. had a poorly defined life history. Gut contents of 16 insect species showed that 4 were predominantly predatory, and the remainder were detritivores. The latter could be categorised as shredders (large particle detritivores) or collector‐browsers which mainly ingested particles in the dominant (<50 μm) size range. Oxygen consumption by fine stream sediments was similar at different times of year which suggests that the food quality of detritus may tie relatively constant at all times. 相似文献
99.
九龙江口春季微型浮游生物数量变动及其与小型水母消长的关系 总被引:2,自引:0,他引:2
通过2011年春季对九龙江口的生态调查,对浮游植物、微型浮游动物以及小型水母的种类组成和数量变动特征并对分粒级叶绿素进行了研究,同时还分析了营养盐、温度和盐度等环境参数。调查共记录浮游植物种类45种,以硅藻门的中肋骨条藻(Skeletonema costatum)、颗粒直链藻(Melosira granulate)、针杆藻(Synedra spp.),以及绿藻门的斜生栅藻(Scenedesmus obliquus)、甲藻门的微小亚历山大藻(Alexandrium minutum),蓝藻门的优美平裂藻(Merismopedia elegans)具有较高的检出率;微型浮游动物分为4大类,红色中缢虫(Mesodinium rubrum)占有最大的比例为55.5%-79.8%,无壳纤毛虫次之,砂壳纤毛虫和无节幼体所占的比例均不足10%;小型水母种类组成中主要以弗洲指突水母(Blackfordia virginica)、球型侧腕水母(Pleurobrachia globosa)、厦门和平水母(Eirene xiamenensis)以及水螅水母幼体(Hydroidomedusae larvae)为主要优势类群,占小型水母总量的85%以上。小型水母数量在4月底和5月初达到丰度最高值(69.49±29.4)ind/L,此时微型浮游动物数量从小型水母出现初期的峰值(1085±574.66)ind/L下降为(526±152.93)ind/L,同时micro级叶绿素占总叶绿素比例达到最大值(42.26±12.94)%。小型水母数量下降后,微型浮游动物的数量回升。在小型水母数量消长过程中,浮游植物、微型浮游动物和小型水母数量间处于动态平衡。 相似文献
100.
北京时间2010年4月14日7时49分青海省玉树藏族自治州玉树县发生7.1级地震。 本文利用Kolmogorow-Smirnov分布检验法, 对玉树地区不同空间范围内1995—2010年小震月频次分布进行了检验, 得到玉树周边地区不同空间范围内小震月频次不服从正态分布和泊松分布, 并根据峰度、 偏度、 标准差σ、 CV值以及bm等统计参数, 对玉树周边不同空间范围内小震活动分布特征的时间变化进行了进一步分析。 结果显示, 在玉树地震前, 不同空间范围内小震月频次的峰度、 偏度、 标准差σ、 CV值以及bm等均表现出明显的异常变化。 相似文献