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991.
ASTRID J. SCHOLZ CHARLES STEINBACK SARAH A. KRUSE MIKE MERTENS HOWARD SILVERMAN 《Conservation biology》2011,25(3):485-492
Abstract: Social, economic, and ecological criteria contribute to the successful design, implementation, and management of marine protected areas (MPAs). In the context of California's Marine Life Protection Act Initiative, we developed a set of methods for collecting, compiling, and analyzing data about the spatial extent and relative economic importance of commercial and recreational fishing. We interviewed 174 commercial fishers who represented the major fisheries in the initiative's north‐central coast region, which extends from Point Arena south to Pigeon Point. These fishers provided data that we used to map the extent of each of the fishing grounds, to weight the relative importance of areas within the grounds, to characterize the operating costs of each fishery, and to analyze the potential economic losses associated with proposed marine protected areas. A regional stakeholder group used the maps and impact analyses in conjunction with other data sets to iteratively identify economic and ecological trade‐offs in designations of different areas as MPAs at regional, port, and fishery extents. Their final proposed MPA network designated 20% of state waters as MPAs. Potential net economic loss ranged from 1.7% to 14.2% in the first round of network design and totaled 6.3% in the final round of design. This process is a case study in the application of spatial analysis to validate and integrate local stakeholder knowledge in marine planning. 相似文献
992.
本文详细分析了高职院校学生中非正式群体产生的心理原因、类型、特征和功能,提出了切实可行的教育对策. 相似文献
993.
ROBERT C. BARBOUR‡ LYNNE G. FORSTER SUSAN C. BAKER† DOROTHY A. STEANE BRADLEY M. POTTS 《Conservation biology》2009,23(5):1146-1155
Abstract: The developing field of community genetics has the potential to broaden the contribution of genetics to conservation biology by demonstrating that genetic variation within foundation plant species can act to structure associated communities of microorganisms, invertebrates, and vertebrates. We assessed the biodiversity consequences of natural patterns of intraspecific genetic variation within the widely distributed Australian forest tree, Eucalyptus globulus. We assessed genetic variation among geographic races of E. globulus (i.e., provenances, seed zones) in the characteristics of tree‐trunk bark in a 17‐year‐old common garden and the associated response of a dependent macroarthropod community. In total, 180 macroarthropod taxa were identified following a collection from 100 trees of five races. We found substantial genetically based variation within E. globulus in the quantity and type of decorticating bark. In the community of organisms associated with this bark, significant variation existed among trees of different races in composition, and there was a two‐fold difference in species richness (7–14 species) and abundance (22–55 individuals) among races. This community variation was tightly linked with genetically based variation in bark, with 60% of variation in community composition driven by bark characteristics. No detectable correlation was found, however, with neutral molecular markers. These community‐level effects of tree genetics are expected to extend to higher trophic levels because of the extensive use of tree trunks as foraging zones by birds and marsupials. Our results demonstrate the potential biodiversity benefits that may be gained through conservation of intraspecific genetic variation within broadly distributed foundation species. The opportunities for enhancing biodiversity values of forestry and restoration plantings are also highlighted because such planted forests are increasingly becoming the dominant forest type in many areas of the world. 相似文献
994.
Maurice Akpan Okoji 《The Environmentalist》2001,21(3):197-203
Forest management in south eastern Nigeria has changed hands from the forest communities to foreign technology. As a result the sustainable, conservative and cyclical use that characterised the communities that lived in balance with their forest resources are no longer practised. Consequently, a great deal of the region's valuable timber trees has been lost and the environmental influences of the forest grossly reduced. The local communities have not only been deprived of a multitude of non-timber forest resources upon which they depend for their survival and well-being but have also lost their knowledge of traditional forest management. Although these consequences are far-reaching, the neglected majority in the rural areas bear the brunt. To save what is left of the once vast forest areas, communities in and around the biome need to be empowered to manage their forest resources. Empowerment will challenge their responsibility and their ability to function for the common good—themselves, the State and the world at large. 相似文献
995.
The use of replicated plot,line and point sampling for estimating species abundance and ecological diversity 总被引:1,自引:0,他引:1
The paper deals with the problem of estimating diversity indexes for an ecological community. First the species abundances are unbiasedly and consistently estimated using designs based on n random and independent selections of plots, points or lines over the study area. The problem of sampling elusive populations is also considered. Finally, the diversity index estimates are obtained as functions of the abundance estimates. The resulting estimators turn out to be asymptotically (n large) unbiased, even if a considerable bias may occur for a small n. Accordingly, the method of jackknifing is made use of in order to reduce bias. 相似文献
996.
广州罗岗村边次生常绿阔叶林群落分析 总被引:10,自引:0,他引:10
根据广州罗岗村这次生常绿阔叶林的调查结果,分析了该群落的组成结构特征在1200m2的样地里有维管束植物引种,隶属于40科65属其区系特点具有从热带向亚热带过渡的性质该群落分为乔木层(3亚层)、灌木层及草本层等层次乔、灌层种类较多,主要以往粟(Caastanopsischinensis)、黄桐(Endospermumchinense)和黄果厚壳桂(CryptocargaconcinnaHance)等种类组成,草本展种类少.本群落以中、小高位芽植物占优势,缺乏大高位芽、隐芽和一年生植物叶型以中型叶为主群落的大部分优势种的种群分布格局是随机分布的优势种群的立木结构分析表明,本群落处于进展演替它与30a前比较有较大的变化乔木层原优势种黄桐、猴耳环(Pithecellobiumclyperia)、亮叶肉实(Sarcospermalaurinum)等被锥粟、刺栲(Castanopsishystrix)等替代.草本层原以禾本科植物为主,现已发展为原生性较强的龙船花(Ixorachinensis)、九节(Psychotriarubra)等种类 相似文献
997.
《环境科学学报(英文版)》2023,35(3):258-265
Glyphosate, the most extensively used herbicide globally, has raised ecotoxicological concerns because it can be transported into the aquatic environment and cause adverse effects on the aquatic system. However, the functional mechanism of glyphosate on cyanobacteria are not completely disentangled. In this study, we selected six common cyanobacteria to evaluate glyphosate effects on cyanobacterial growth in monoculture experiment. Results showed that the growth of five tested cyanobacterial species were promoted under different degrees, and only Pseudanabaena was inhibited by glyphosate. In the phylogenetic tree based on gene sequences of 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS), a target for glyphosate, we found that the position of Pseudanabaena is the closest to plant, which was sensitive to glyphosate, thereby explaining the inhibitory effect of Pseudanabaena following glyphosate exposure. The primary degraded metabolites or analogs did not induce cyanobacterial growth, laterally demonstrating that glyphosate was used as a source of phosphorus to accelerate cyanobacterial growth because phosphorus levels increased in the medium of glyphosate treatment. Overall, this study provides a better understanding of the influence of glyphosate on the composition of aquatic microbiota and explains the mechanism of cyanobacterial response to glyphosate. 相似文献
998.
Joachim Lambert 《International journal of occupational safety and ergonomics》2013,19(2):179-184
Conformity assessment procedures prescribed by European legislation are presented and their concrete implementation is illustrated by the example of personal protective equipment (PPE). The different categories of PPE defined by Council Directive 89/686/EEC are explained with reference to the applicable conformity assessment elements. Quality assurance of production is presented as the central element of the conformity assessment procedure for complex PPE. Special emphasis is put on the necessity of having a regular exchange of views and information among notified bodies in Europe. Ways in which third countries can eventually carry out conformity assessment on the basis of a contract with the European Community Commission are explained. 相似文献
999.
采用好氧/缺氧连续流砂过滤器中试实验研究深度处理北京某污水处理厂二级出水。实验结果表明,当连续流砂过滤器好氧段聚合氯化铝投量为20 mg/L,缺氧段碳源投量为32 mg/L时,COD、NH+4-N、TN和TP的平均去除率分别为34.77%、86.54%、66.94%和84.10%,最终出水均达到北京市新(改、扩)建城镇污水处理厂排放A标准(DB11/890-2012)。克隆文库法分析石英砂表面生物膜中的细菌群落结构表明,其优势菌群为β-proteobacteria,其中大部分能以废水中碳源为电子供体还原硝酸盐。 相似文献
1000.
通过检测活性污泥的电子传递体系活性以及生物多样性,研究Ni2+对活性污泥微生物活性及群落多样性的影响。结果表明:与对照系统相比,5mg/L的Ni2+对2,3,5-lriphenylteItrazoliumchloride(TTC.ETS)活性未产生显著的影响;但当Ni2+的浓度进一步增大到10、20和40mg/L后,其对序批式反应器内活性污泥TTC—ETS活性的抑制率分别达到(36.794-11.14)%、(55.88±13.90)%和(70.97±6.78)%。低浓度Ni2+.能增强活性污泥微生物对碳源的利用,但高于10mg/L的Ni2+则显著抑制了活性污泥微生物对碳源的利用。各个SBR系统中微生物群落最常见的物种相近,物种丰富度和均一性则均有所不同,其中群落物种丰富度随着Ni2+浓度的增加而逐渐减小。TTC—ETS活性、平均每孔颜色变化率、Shan—liOn指数和Simpson指数,与Ni2+的胁迫浓度之间的显著相关性表明,它们均可有效地表征Ni2+胁迫对活性污泥微生物活性及群落多样性的影响程度。 相似文献