Do wildlife habitat strips act as refuges for mature-forest carabid beetle assemblages? A case-study in Tasmanian wet eucalypt forest,Australia

Carabid beetles (Insecta: Coleoptera: Carabidae) were sampled with pitfall traps in central Tasmania to assess the conservation utility of wildlife habitat strips (WHS) in native high-altitude wet eucalypt forest. Sampling followed a Before-After, Control-Impact design, with replicated samples being collected at one control site and two treatment sites, both before harvesting and then again seven to eight years after the harvest that established the WHS. Catches of carabid beetles decreased in harvested areas, but there were great increases in species richness and gross changes in assemblage composition — largely attributable to the colonisation of young-forest specialist species. Assemblages in the control site remained essentially unchanged, and were dominated by mature-forest specialist species. Assemblages in the WHS changed little compared to their pre-harvest condition, but assemblage structure was slightly affected. In this particular landscape, WHS appear to effectively maintain carabid assemblages typical of intact mature native forest, at least in the short-term. A broader and longer-term assessment of the ecological performance of WHS across Tasmania would be required to assess the long-term viability of WHS as a conservation strategy for carabids and other species requiring mature forest.     

Is forest mushroom productivity driven by tree growth? Results from a thinning experiment

? Most of the edible forest mushrooms are mycorrhizal and depend on carbohydrates produced by the associated trees. Fruiting patterns of these fungi are not yet fully understood since climatic factors alone do not completely explain mushroom occurrence.

? The objective of this study was to retrospectively find out if changing tree growth following an increment thinning has influenced the diversity patterns and productivity of associated forest mushrooms in the fungus reserve La Chanéaz, Switzerland.

? The results reveal a clear temporal relationship between the thinning, the growth reaction of trees and the reaction of the fungal community, especially for the ectomycorrhizal species. The tree-ring width of the formerly suppressed beech trees and the fruit body number increased after thinning, leading to a significantly positive correlation between fruit body numbers and tree-ring width.

? Fruit body production was influenced by previous annual tree growth, the best accordance was found between fruit body production and the tree-ring width two years previously.

? The results support the hypothesis that ectomycorrhizal fruit body production must be linked with the growth of the associated host trees. Moreover, the findings indicate the importance of including mycorrhizal fungi as important players when discussing a tree as a carbon source or sink.

     

Enhancing conservation of Australian freshwater ecosystems: identification of freshwater flagship fishes and relevant target audiences

Flagship species, especially mammals and birds, are commonly used to increase awareness of conservation issues in marine and terrestrial ecosystems. However, flagship species oriented programs are often ad hoc with initiatives scarce in the freshwater context. Here, we aim to identify potential flagship candidates that would appeal to a broad cross section of society at a continental scale where freshwater ecosystems are under threat from human impacts. We identified 19 species from a list of 299 Australian freshwater fishes on the basis of body size, trophic guild and threatened species status assuming these characteristics of flagship species are transferable from previous work on terrestrial flagship species. We considered the potential of species to be of international appeal but focused mostly on eight relevant interest groups within Australia. This followed the rationale that public engagement with conservation issues in freshwater systems might be more effective if the link between fish species and the decisions people make were better understood, and we acknowledge the diverging interests of stakeholders. This scoping work contributes towards addressing the challenges of connecting societies to the principles of sharing water resources with ecosystems, and represents the first continental‐scale assessment of its kind.     

中国大蒜种质资源遗传多样性和群体遗传结构分析

【目的】从分子水平了解中国大蒜种质资源的群体遗传结构和遗传背景。【方法】利用AFLP、SSR和InDel这3种分子标记对国家无性繁殖蔬菜资源圃保存的212份大蒜资源进行检测,通过Mega软件进行最大相似性聚类分析,Structure 2.1软件进行群体遗传结构分析,SSPS软件进行分子标记与大蒜辣素含量和21个数量性状进行一元线性模型检测,考察两者之间的关联性及群体遗传结构的影响。【结果】3种分子标记在212份种质中扩增出502个位点,多态性位点为492个。群体遗传结构与聚类分析均将所有资源划分为5个群体,划分的类别基本一致。然而,群体遗传结构分析划分的5个群体,群内遗传信息多样性指数较小。对212份种质的22个数量性状与分子标记的线型模型分析表明,包括大蒜辣素含量在内的多个数量性状受群体遗传结构的影响较小。【结论】中国大蒜种质资源遗传背景丰富,群体遗传结构对数量性状的分布影响较小,适合进一步进行性状与分子标记之间关联分析研究。     

ECONOMIC FEASIBILITY OF SMALL-SCALE BLACK-LIPPED PEARL OYSTER (PINCTADA MARGARETIFERA) PEARL FARMING IN THE CENTRAL PACIFIC

ABSTRACT

This work provides an analysis of the economic feasibility of one of many small-scale aquaculture operations being considered, black pearl oyster farms, as one type of supplemental economic activity for outer island communities in the Central Pacific. Specifically, projections of financial performance of a small-scale 25,000 seeded pearl oyster farm using the Tahitian long-line method are being conducted. Estimates of initial capital investment and annual operating costs are being formulated, an annual cash flow and enterprise budget are being developed. Results show that initial capital investment is $202,076. Annual operating expenses are $293,726 during full operation. The largest costs contributing to annual operating expenses are seeding (46%), labor including farm owner's opportunity cost (24%), and depreciation (9%). The base model presented in this work suggests profitability over a 20-year horizon.

Net returns over a 20-year farm horizon based on an 8% discount rate indicate a positive NPV of $ 102945. Sensitivity analysis on profit due to the variability of market price, survival, and cost of seed and other inputs are conducted and results presented.     

基于不等分模型的差动偏心齿轮系分插机构运动分析

针对等分模型存在模型假设引起的转角误差问题,提出了一种准确计算偏心渐开线齿轮转角关系的不等分模型及解法.该模型校正了等分模型下配对齿工作齿廓的交叉或分离,当基准齿工作齿廓坐标点数为5000点时,啮合点搜索的坐标控制精度可达到0.001 mm,转角误差精度可达到0.001°.计算表明,转角误差随着齿轮偏心率的增大而变大,多级传动时转角误差被逐级放大.不等分模型解法可以求得偏心齿轮系分插机构齿轮盒和栽植臂准确的相对运动关系,从而得到秧爪取秧和推秧准确的位置与姿态.正、反侧从动齿轮输出转角在180°处不等于中心轮转角,使得正向侧和反向侧栽植臂的秧爪轨迹不重合,ADAMS仿真结果验证了不等分模型求解的正确性.当偏心率为0.1043时,两者的轨迹偏差不大于1.01 mm.     

Managing inequality or managing stocks? An ethnographic perspective on the governance of small‐scale fisheries

A growing volume of recent research on small‐scale fisheries governance has a focus on local perspectives and priorities of small‐scale fisherfolk. This paper develops from this local perspective a novel focus on what is a fundamental priority of many small‐scale fishers: concerns about inequality. The paper begins with a critical review of the literature on small‐scale fisheries governance and suggests how a focus on inequality can make a useful contribution. The paper uses case‐studies of small‐scale fisheries in Papua New Guinea (PNG) and the Philippines to highlight local priorities about inequality and the implications for small‐scale fisheries governance. PNG and the Philippines have very different social, political and environmental contexts, yet in both cases, local inequalities were a key pre‐occupation of fisherfolk and posed major challenges for fisheries governance. While in both of the case‐studies, fishers were aware of and keen to act on resource sustainability, this concern was overridden by concerns over: who obtained benefits from the fishery; who was responsible for resource degradation; and who should bear the costs of regulation. We conclude by discussing how our emphasis on the importance of inequality at a local level can potentially be integrated within many influential approaches to small‐scale fisheries governance.     

Occurrence of demersal fishes in relation to near‐bottom oxygen levels within the California Current large marine ecosystem

Various ocean‐climate models driven by increased greenhouse gases and higher temperatures predict a decline in oceanic dissolved oxygen (DO) as a result of greater stratification, reduced ventilation below the thermocline, and decreased solubility at higher temperatures. Since spreading of low oxygen waters is underway and predicted to increase, understanding impacts on higher trophic levels is essential. Within the California Current System, shoaling of the oxygen minimum zone (OMZ) is expected to produce complex changes. Onshore movement of the OMZ could lead to habitat compression for species with higher oxygen requirements while allowing expansion of species tolerant of low bottom DO. As part of annual groundfish surveys, we sampled catch across a range of conditions from the upper to the lower limit of the OMZ and shoreward across the continental shelf of the US west coast. DO ranged from 0.02 to 4.25 mL L^?1 with 642 stations (of 1020 sampled) experiencing hypoxic conditions in 2008–2010. Catch and species richness exhibited significant and positive relationships with near‐bottom oxygen concentration. The probability of occurrence was estimated for four species (spotted ratfish, petrale sole, greenstriped rockfish and Dover sole) using a binomial Generalized Additive Model. The models for each species included terms for position, day of the year, salinity, near‐bottom temperature and the interaction term between depth and near‐bottom DO. Spotted ratfish and petrale sole were sensitive to changes in near‐bottom oxygen, while greenstriped rockfish and Dover sole show no changes in probability of occurrence in relation to changes in oxygen concentration.