Estimating understory vegetation response to multi-nutrient fertilization in Douglas-fir and ponderosa pine stands

Models were developed to predict understory vegetation response to multi-nutrient fertilization at six conifer-forested stands in the inland Northwest United States. Equations are presented to estimate how fertilization as well as other factors impacting understory production in the inland Northwest change total understory vegetation production and the production of three individual lifeforms (shrubs, forbs, and grasses and grass-likes). Overstory stand density was found to have the greatest impact on understory production, and regardless of factors such as fertilization or precipitation, large stand densities will limit understory production. At lower stand densities, multi-nutrient fertilization as well as greater amounts of precipitation will increase understory production. These factors were also found to be synergistic; thus, greater amounts of precipitation increase the effects of multi-nutrient fertilization on understory production. For sites of the same stand density, Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] was shown to have a greater negative impact on understory production than ponderosa pine (Pinus ponderosa Dougl. ex Laws.). The models predict that multi-nutrient fertilization of ponderosa pine stands will produce increases in understory production across a broader range of stand densities.     

广西冬季2次农业致灾暴雨天气湿位涡分析

为了提高冬季暴雨预报准确率,及时为政府和人民提供准确的预报服务,减少农业生产的损失,利用自动站雨量资料以及NECP FNL分析资料分别对广西冬季两次农业致灾暴雨2016年1月27—28日和2013年12月13—16日进行实况分析、天气学分析和湿位涡诊断分析。结果表明：暴雨发生在MPV1正值区前侧的负值区或0值附近和MPV2负值中心南侧的低值区内。MPV1和MPV2对两类降水落区均具有一定的指示意义,但MPV1中心不能决定锋面暴雨降水落区却对降水具有潜势预报,MPV2对强降水的发生有一定的提前预报。MPV等值线密集区,冷暖空气交汇强烈有利于水汽辐合、垂直涡度发展易产生暴雨。     

中国西北内陆地区新生代孢粉植物群演化的再认识

结合我国西北地区已发表的最新古地磁研究成果,对该区16个新生代沉积盆地的孢粉组合重新进行了总结,以期发现孢粉植物群演化的规律,并修正对我国西北地区古气候和古环境的认识。     

基于多级模糊综合评价法的内河运输可持续发展能力评价研究

内河运输可持续系统是一个新而复杂的概念,对其评价研究具有重要的理论意义和现实意义;通过回顾国内外在运输与内河运输生态可持续性方面的相关研究,应用多级模糊综合评价法进行了综合评价。结果表明:在评价过程中,应用模糊综合评价法,能将各种因素综合进行考虑,降低了加权平均评价主观臆断的程度,评价结果较传统的二元值评价准确、科学,同时,计算方法简单,易操作,便于在实际工作中应用,保证了评价工作的适用性和可操作性。     

MEY = MSY

It has been generally accepted for more than half a century that the fishing sector stood to gain from managing fisheries at the effort level producing maximum economic yield (MEY) rather than at the higher effort level producing maximum sustainable yield (MSY). However, the acceptance is built on evaluating only the revenue and cost structure for the fishing fleet, not for the overall fishing sector including processing, distribution and marketing of fish products. Considering these links of the fish value chain moves the MEY-level closer to, but slightly below the MSY-level. For society as a whole, this means that MSY is the more appropriate target reference level.     

Quantitative ecological risk assessment for fishing effects on diverse data-poor non-target species in a multi-sector and multi-gear fishery

Assessment of ecological sustainability for all species impacted by fishing is one of the most important and practical steps towards an Ecosystem Approach to Fisheries. We extend methods for Sustainability Assessment for Fishing Effects (SAFE) to assess diverse bycatch species in a multi-sector and multi-gear fishery. We develop methods for estimating fishing mortality rate, based on limited data, for demersal trawl, Danish seine, gillnet, and longline. The general approach involves estimating spatial overlap between species distribution and fishing effort distribution, catchability resulting from probability of encountering the gear and size-dependent selectivity, and post-capture mortality. We define three reference points (F_msm, F_lim, and F_crash) and use six methods to derive these reference points. As an example, we apply this method to nearly 500 fish species caught in the Southern and Eastern Scalefish and Shark Fishery, a multi-sector and multi-gear fishery in Australia. We assess sustainability risk for all captured fish species in each sub-fishery and the cumulative impact across all the sub-fisheries. The results indicate that chondrichthyans are more vulnerable to fishing impact than teleosts, and that impact differs among sectors of the fishery. This method could be easily applied to other fisheries. However, the results may require fine tuning by other means such as expert judgment.     

渔具材料专业标准体系现状与发展对策

本文介绍了我国渔具材料专业标准体系的研究现状及存在问题,就标准体系表的研究过程、组成、结构和层次,以及今后工作等作了简要分析和探讨。为进一步发展我国渔具材料标准体系,在采用国际和国外先进标准,加大经费投入力度,加快已落实项目的工作进度,加强产品标准与方法标准的衔接,加大标准的宣传、贯彻和监督力度,以及加强同标准化各主管部门的联系等方面提出了合理化建议。     

闽中地区单拖作业捕捞能力的因子分析

单拖作业是福建省闽中地区重要的作业渔具之一。在捕捞生产过程中渔具受到诸多因素的影响,各种因素对渔具捕捞能力的影响程度不同,给捕捞力量的量化计算和管理带来困难。为了了解各因子对单拖作业捕捞能力发挥的影响程度,本文选择影响单拖捕捞能力发挥的12个因子指标,采用因子分析法对其进行分析。结果表明,可将影响单拖捕捞能力发挥的诸多因素归并为网具结构、渔船作业能力、船龄、渔民捕捞技能4个公共因子,它们在单拖捕捞过程中所做的贡献率依次为网具结构52.87%,渔船作业能力24.46%,船龄7.05%,捕捞技能4.73%。本文还计算和讨论了各样品船的因子得分,通过各因子的得分和综合得分,可对各样品船的捕捞能力发挥情况进行综合评价,为渔业生产和管理提供参考。     

闽南、台湾浅滩渔场单拖渔业监测调查

本文根据2005年1~11月闽南、台湾浅滩渔场单拖渔业调查监测资料,分析和研究该海区单拖渔业利用状况、主要渔获物资源动态。结果表明:2005年渔获量平均密度指数(CPUE)3月最高,达134.41kg/h,随后迅速下降,9月为全年最低,仅34.75kg/h;渔获物组成以生命周期短、个体小、营养级较低的种类为主,二长棘鲷居绝对优势,占总渔获重量的38.8%;各主要种类渔业资源时空分布变化较为明显;近十年来,渔船功率和网具的日趋大型化,小型单拖渔船数量有所减少。通过监测调查为渔业管理部门制订科学的渔业资源养护措施、加强和完善渔业管理等提供科学依据。     

Contrasting recreational and commercial fishing: Searching for common issues to promote unified conservation of fisheries resources and aquatic environments

Commercial fishing has repeatedly been identified as a major causal factor for global declines in fish stocks. Recently, recreational fisheries have also been considered as having the potential to contribute to fisheries declines. Here, we take a global focus, contrasting the characteristics of commercial and recreational fisheries relevant to conservation and sustainability of exploited fishes in both marine and freshwater environments. We provide evidence to support our assertion that the same issues that have led to global fisheries concerns regarding commercial fishing can have equivalent, and in some cases, magnified effects in recreational fisheries. Contrasts revealed that the issues of bycatch and catch-and-release, fisheries-induced selection, trophic changes, habitat degradation, gear technology, fishing effort, and production regimes are remarkably similar among fishery sectors. In recognition of this conclusion, we present a new vision for recreational fishing that positions it on the same scale and urgency as commercial fisheries. Efforts to manage and conserve fisheries must recognise that issues and threats are similar in these fundamentally and philosophically different fisheries, as may be the solutions. Failure to recognise the similarities will further polarise these sectors and retard efforts to conserve aquatic resources. Fishing activity of any kind, whether commercial or recreational, has the potential to affect negatively fish and fisheries, as well as aquatic environments.