Releasing Adults versus Young in Reintroductions: Interactions between Demography and Genetics

Abstract:  We integrated genetics and demography into population modeling in the context of species restorations, in which both the origin of released individuals and the management strategy may influence the success of introduction. Through an explicit individual-based simulation approach, we investigated the effects of the age of released individuals by exploring the relative merits of releasing juveniles or adults to establish populations. We included the effect of genetic variability responsible for inbreeding depression and mutational meltdown. Our general analysis uncovered an interaction between the age of founders and the extent of intrapopulation fitness variability, which substantially influenced the efficiency of selection in populations founded by juveniles and had subsequent positive consequences for long-term persistence compared with the case in which adults were released. We then applied the model to the case of the reintroduction of the Griffon Vulture ( Gyps fulvus fulvus ) to southern France, for which post-release data were available. The demographic aspects of this reintroduction were already analyzed and published, suggesting that it is more efficient to release adults than juveniles, despite an observed reduction of demographic parameters following the release of adults. In that context, the inclusion of genetic considerations qualitatively changes the conclusion, predicting reduced long-term extinction risk if juveniles rather than adults are released.     

Why do Varroa mites invade worker brood cells of the honey bee despite lower reproductive success?

Varroa jacobsoni reproduces both in drone and worker brood cells of honey bees, but in drone cells reproductive success is higher than in worker cells. A simple model using clonal population growth as a fitness measure has been developed to study the circumstances under which specialization on drone brood would be a better strategy than reproduction in both types of cell. For European Apis mellifera, the model suggests that if mites have to wait less than 7 days on average before they can invade a drone cell, specialization on drone brood would be a better strategy. This is close to the estimated waiting time of 6 days. Hence, small differences in reproductive success in drone and worker cells and in the rate of mortality may determine whether specialization on drone brood will be promoted or not. In European A. mellifera colonies, Varroa mites invade both drone and worker cells, but specialization on drone brood cells seems to occur to some extent because drone cells are more frequently invaded than worker cells. In the parasite-host association of V. jacobsoni with African or Africanized A. mellifera or with A. cerana, the mites also invade both drone and worker cells, but the mites specialize on drone brood for reproduction since a large percentage of the mites in worker brood do not reproduce. Only in the parasite-host association of Euvarroa sinhai, a mite closely resembling V. jacobsoni, and A. forea is specialization complete, because these mites only invade drone brood.     

重大突发事件下应急冷链供应链协同化评价模型及策略研究*

为有效规避冷链供应链受突发事件带来的不利影响,并强化其应急体系协同化发展,提出基于层次分析法和序参量法的应急冷链供应链协同化水平评价模型。模型以供应链协同化理论为基础,从协同化目标入手构建影响其协同化水平的测度指标体系;利用层次分析法确定评价指标的综合权重,最后运用序参量法评估冷链供应链各应急环节的协同度。结果表明:评价模型能有效评估应急冷链供应链协同化水平,可为冷链供应链应对突发事件提供参考。     

我国医疗废物领域履行POPs公约对策研究

文章根据POPs公约对医疗废物管理和处置的总体要求,结合我国目前医疗废物管理和技术应用现状,结合我国医疗废物处置设施污染物排放、工程建设及运行管理状况,从医疗废物处理技术的具体应用实际需要出发对如何推进采用BAT/BEP,推进中国该领域履约进程进行了探讨,并提出了我国医疗废物领域履行POPs公约的管理和技术对策。     

废印刷线路板中贵金属金的浸取研究

采用盐酸和氯酸钠作为反应试剂,从印刷电路板废料中回收金。考察了盐酸浓度、氯酸钠用量、固液比、浸取时间条件对反应的影响。实验结果表明:酸度过高或过低对金的收率都不利;对于5g废料、以固液比1:8,4g氯酸钠,3mol/L盐酸,搅拌1h进行反应,金的回收率可达90%以上。所用试剂廉价易得,设备简单,操作方便:反应过程中无有害物产生,实现了贵重资源的再生利用。     

电子线路板蚀刻废液中铜的回收新工艺

文章简述电子线路板蚀刻工艺中含铜酸性和碱性废液的处理回收工艺,采用本工艺回收生产饲料级硫酸铜,不仅成功地解决了该类含铜废液的达标排放问题,而且操作简单,生产的饲料级硫酸铜质量稳定、生产能耗低,其他副产物也得到回收,该工艺具有明显的社会效益、经济效益和环境效益。     

生物膜对日常生产、生活的影响与作用

自然环境中生物膜随处可见。生物膜在污水处理以及河流水质净化等方面具有保护水环境的积极作用。然而,生物膜也存在着相当的负面影响,这些负面影响不仅危及到人们的日常生活和健康,而且还会腐蚀管道和船体等金属材料。本文总结和分析生物膜在环境中对人类生产、生活的利弊,目的是使人们了解和认识生物膜的正反两方面影响,以推动对生物膜利用或抑制等方面的研究。     

城市内河蓝藻复苏和生长规律研究

主要探讨城市化对城市内河蓝藻复苏和生长的影响。这些影响包括河流中营养物的升高、高等水生植物的灭绝、河水所受光照强度的变化以及由河水滞流带来的水体复氧效率降低对内河中蓝藻爆发条件的影响。通过实验我们发现金鱼藻与水网藻的存在可以在一定程度上抑制蓝藻的生长,金鱼藻的效果比水网藻更明显。适宜的光照是蓝藻大量生长的条件。对水体进行曝气复氧可以抑制蓝藻的生长。     

Potential of anaerobic digestion for material recovery and energy production in waste biomass from a poultry slaughterhouse

This study was carried out to assess the material and energy recovery by organic solid wastes generated from a poultry slaughterhouse. In a poultry slaughterhouse involving the slaughtering of 100,000 heads per day, poultry manure & feather from the mooring stage, blood from the bleeding stage, intestine residue from the evisceration stage, and sludge cake from the wastewater treatment plant were discharged at a unit of 0.24, 4.6, 22.8, and 2.2 Mg day^?1, consecutively. The amount of nitrogen obtained from the poultry slaughterhouse was 22.36 kg 1000 head^?1, phosphate and potash were 0.194 kg 1000 head^?1 and 0.459 kg 1000 head^?1, respectively. As regards nitrogen recovery, the bleeding and evisceration stages accounted for 28.0% and 65.8% of the total amount of recovered nitrogen. Energy recovered from the poultry slaughterhouse was 35.4 N m³ 1000 head^?1 as CH₄. Moreover, evisceration and wastewater treatment stage occupied 88.1% and 7.2% of the total recovered CH₄ amount, respectively.     

The role of life histories and trophic interactions in population recovery

Factors affecting population recovery from depletion are at the focus of wildlife management. Particularly, it has been debated how life‐history characteristics might affect population recovery ability and productivity. Many exploited fish stocks have shown temporal changes towards earlier maturation and reduced adult body size, potentially owing to evolutionary responses to fishing. Whereas such life‐history changes have been widely documented, their potential role on stock's ability to recover from exploitation often remains ignored by traditional fisheries management. We used a marine ecosystem model parameterized for Southeastern Australian ecosystem to explore how changes towards “faster” life histories might affect population per capita growth rate r. We show that for most species changes towards earlier maturation during fishing have a negative effect (3–40% decrease) on r during the recovery phase. Faster juvenile growth and earlier maturation were beneficial early in life, but smaller adult body sizes reduced the lifetime reproductive output and increased adult natural mortality. However, both at intra‐ and inter‐specific level natural mortality and trophic position of the species were as important in determining r as species longevity and age of maturation, suggesting that r cannot be predicted from life‐history traits alone. Our study highlights that factors affecting population recovery ability and productivity should be explored in a multi‐species context, where both age‐specific fecundity and survival schedules are addressed simultaneously. It also suggests that contemporary life‐history changes in harvested species are unlikely to increase their resilience and recovery ability.