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81.
为明确兜兰属(Paphiopedilum)宽瓣亚属(Subgenus.Brachypetalum)植物各物种在我国的生存现状与濒危状况,在大量的野外调查和文献、标本数据收集的基础上,对其种群分布、数量、生境特征、市场贸易、受威胁因素、保护现状与保护成效进行统计分析,并依据《IUCN红色名录等级和标准(3.1版)》对该类群的濒危等级进行重新评估.结果表明,野外调查到硬叶兜兰(Paphiopedilum.micranthum)、麻栗坡兜兰(P.malipoense)、杏黄兜兰(P.armeniacum)、白花兜兰(P.emersonii)、巨瓣兜兰(P.bellatulum)、文山兜兰(P.wenshanense)、同色兜兰(P.concolor)7个目标物种,已知分布于我国50个县(市、区),共计194个自然分布点.宽瓣亚属植物在我国水平方向上主要分布于滇东南、黔西南、黔东北、滇西北、桂北与黔南交界处以及桂西北至桂西南等地区;垂直方向上集中分布于中高海拔段(780~1267m),平均海拔997m;在全国大尺度上,该亚属整体呈零散分布,区域小尺度上个体呈聚集生长;其小生境具有高海拔、透水、透气、喜阴、喜钙的特点.市场调查的贸易率为36.67%,贸易价格高低不等,具有较强的随机性;贸易来源主要为野外采挖,占贸易数量的88.32%,具有较强的地域性;贸易方式为现场和线上网络交易,具有较强的灵活性.该类群主要受到采挖和生境退化的威胁,分别占所有分布点的44.85%、29.83%.宽瓣亚属整体就地保率仅为34.53%,保护成效为一般保护;调查的29个保育地中,有20个保育地对该类群累计保育98次,除文山兜兰和绿叶兜兰外,其他7种迁地保护成效被评估为合适.巨瓣兜兰、文山兜兰由原来的濒危(EN)评估为极危(CR);麻栗坡兜兰、白花兜兰、杏黄兜兰评估等级未发生变化,仍为极危(CR);硬叶兜兰和同色兜兰由原来的易危(VU)评估为濒危(EN);德氏兜兰、绿叶兜兰被评为数据缺乏(DD).  相似文献   
82.
In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90, BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7 (municipal waste dumping) and 8 (medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5 (Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9 (urban), 10 (sub-urban), 11 (rural) while sites-7 and 8 (urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites-7 and 8. Values of incremental lifetime cancer risk were from 10−9 to 10−11 showed no carcinogenic health risk by road dusts contaminated with the heavy metals.  相似文献   
83.
In this final component of a three-part review, we present a national synthesis and evaluation of approaches for monitoring, assessing and reporting estuarine condition across Australia. Progress is evaluated against objective criteria that together provide a model of international best practice. We critically assess the limitations, inconsistencies and gaps that are evident across Australian jurisdictions, and identify common obstacles to future progress. Major strengths and successes are also highlighted, together with specific examples of best practice from around Australia that are transferable to other States and beyond. Significant obstacles to greater national coordination of monitoring and reporting practices include inconsistent spatial scales of management, pluralistic governance structures and the lack of any overarching legislation. Nonetheless, many perceptible advances have been made over the last decade across Australia in estuarine monitoring and health assessment, and there is great potential for further progress. Finally, we provide a list of recommendations to address some of the most pressing limitations and gaps, and support improved future monitoring, assessment and reporting for Australian estuaries.  相似文献   
84.
河口湿地是陆海相互作用强烈的重要地球关键带,同时还受到人类活动的强烈影响.黄河三角洲湿地作为年轻的暖温带河口湿地,其微塑料污染状况尚未得到充分研究.因此对黄河三角洲湿地表层沉积物中微塑料的形态、丰度、粒径和成分组成进行了测定,并使用污染负荷指数(PLI)和潜在污染风险指数(PRI)评估了研究区域微塑料污染状况和生态风险.结果表明,黄河三角洲湿地微塑料丰度为20~520 n ·kg-1,中值为150 n ·kg-1.微塑料形貌以纤维和黑色为主,粒径在1 mm以上,成分多为人造丝、聚乙烯、聚酯纤维和聚对苯二甲酸乙二醇酯等.湿地中微塑料的PLI值介于0.04~0.96之间,PRI值介于0.00~171.60之间,表明黄河三角洲湿地微塑料污染处于轻微污染和低生态风险水平.  相似文献   
85.
Picea neoveitchii is an endemic species in China. It had been listed as an endangered species in red data books. It scatters in several locations of south slope of the Qinling Mountain of China. Upon reviewing the related literature, discussing with leading scholars on gymnosperm, ecology and plant conservation, the field survey was carried out in four locations. There are eleven mature individuals and two seedlings surviving in its natural habitats. With the survey of quadrat method in four locations, related community index were calculated such as relative important value (RIV), species richness, similarity index, diversity index and evenness index etc. The community could be sorted and characterized as three groups based on the community parameters. The analysis of vegetation table elucidates that Picea neoveitchii is a dominant species with low grouping rate in most surveyed sites. The RAPD analysis shows target species has intraspecific genetic variability. The estimation of Shannon's phenotypic diversity index (Ho) also explains the difference of genetic variations of different locations. Due to the lack of enough knowledge and professional guide of conservation biological perspective, Picea neoveitchii had been clear-cut for timber production. The extent of occurrence and area of occupancy declined rapidly from 1950s to 1990s. According to the Conservation Category guideline proposed by the World Conservation Union, the conservation status of Picea neoveitchii was reevaluated as Critically Endangered (CR) B2b C2a D. Upon research in areas of ecology, molecular biology, cluster analysis of environmental parameters, a practical conservation strategy is recommended in this research.  相似文献   
86.
Mercury (Hg) is a ubiquitous and a major environmental metal pollutant in the aquatic ecosystem. The present study was performed to evaluate the effect of mercury graded doses exposure on oxidative stress, redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali. Specimens were exposed for 96?h to three concentrations of Hg (40, 80 and 160?µg/L). Exposure of H. forskali to Hg promoted oxidative stress with an increase in malondialdehyde (MDA), protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. An increase of glutathione (GSH), vitamin C (ViteC) and non-protein thiols (NPSH) contents was also observed. Additionally, antioxidant activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) increased especially with the highest doses of Hg indicating a great defense of the antioxidant system. Our investigation revealed an increase in total Metallothionein (MT) content which was more pronounced at the sharpest concentrations of Hg. A significant decline of AChE activity was also observed. In the intestine of Hg-treated H. forskali genotoxicity was confirmed by DNA degradation.  相似文献   
87.
安全生产标准是规范企业安全生产工作的基础性规范,是安全生产法律体系的重要组成部分,也是安全生产监管监察执法的重要依据。为掌握安全生产标准现状,收集、梳理了已发布的安全生产标准603项和正在研制阶段的标准385项,对标准发布年份、在研标准计划年份、标准领域分布、标准级别和标准性质多个维度进行分析,总结标准工作存在的问题,提出安全生产标准制(修)订及发展建议,为安全生产标准工作的持续完善提供参考。  相似文献   
88.
本文阐述了加强野生动物保护管理的重要性,并对衡阳市野生动物管理的现状及存在的问题进行了认真的分析,提出相应的对策与措施,藉以推动衡阳市野生动物保护事业的发展.  相似文献   
89.
西藏自治区自然保护区事业的现状和展望   总被引:1,自引:0,他引:1  
介绍了西藏自治区保护区事业的发展概况和现状,指出了目前保护区建设与管理中存在的主要问题,对今后保护区的规划与发展提出了意见和建议。  相似文献   
90.
A key question of evolutionary importance is what factors influence who becomes dominant. Individual genetic variation has been found to be associated with several fitness traits, including behaviour. Could it also be a factor influencing social dominance? We investigated the association between social status and the amount of intra-individual genetic variation in juvenile brown trout (Salmo trutta). Genetic variation was estimated using 12 microsatellite loci. Dominant individuals had higher mean heterozygosity than subordinates in populations with the longest hatchery background. Heterozygosity–heterozygosity correlations did not find any evidence of inbreeding; however, single-locus analysis revealed four loci that each individually differed significantly between dominant and subordinate fish, thus giving more support to local than general effect as the mechanism behind the observed association between genetic diversity and a fitness-associated trait. We did not find any significant relation between mean d 2 and social status, or internal relatedness and social status. Our results suggest that individual genetic variation can influence dominance relations, but manifestation of this phenomenon may depend on the genetic background of the population.  相似文献   
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