Intraguild predation and mesopredator release effect on long-lived prey

Complete extirpation of a species can generate cascading effects throughout an ecosystem, yet are precisely the goal of island eradications of pest species. “Mesopredator release effect”, an asymmetrical special case of intraguild predation, has been hypothesised as a possible indirect effect from eradications, where superpredator removal can generate a mesopredator increase which may increase the impact on their shared prey. Theoretically this suggests that for intraguild predators, the superpredator may protect the shared prey from mesopredation, and removal of superpredators alone is not recommended. We create a model of long-lived age-structured shared prey and explore the non-equilibrium dynamics of this system. The superpredator can impact all prey life-stages (adult survival and reproductive success) whereas the smaller mesopredator can only impact early life-stages (reproductive success). This model is independently tested with data from a closed oceanic island system where eradication of introduced intraguild predators is possible for conservation of threatened birds. Mesopredator release only occurs in strongly top-down moderated (resource-abundant) systems. Even when mesopredator release can occur, the negative impact of more mesopredators is outweighed by the benefit of superpredator removal, allowing recovery of the prey population. Results are robust to 10% variation in model parameters. The consideration of age-structured prey contradicts previous theoretical results for mesopredator release effect and intraguild predation. Superpredator eradication is vital for population recovery of long-lived insular species. Nonetheless island conservation must retain a whole-ecosystem perspective given the complex trophic relationships among multiple species on islands.     

Landsenses pattern design to mitigate gale conditions in the coastal city – a case study of Pingtan,China

ABSTRACT

Due to the special geographic locations and multiple typhoons a year, the frequent strong winds bring great discomfort and danger to the daily lives of the urban residents in southeast coast of China. The strategic design of landsenses pattern on different scales can help reduce gale days in urban areas while delivering diverse additional benefits such as pollution control and biodiversity habitat protection. Although the greatest gale days are observed in cold and damp winters, there is comparatively little information available for land managers to determine an appropriate strategy for landsenses pattern design under these climatic conditions. We present a framework for prioritization and selection of landsenses pattern for gale day reductions. The framework is supported by examining the relationships between urban landsenses pattern evolution and gale day mitigation in the past, with which we used to develop implementation guidelines that maximize reductions of urban surface gale days. We focus particularly on quantifying the benefits of four types of landsenses: land-use patterns, urban road network, architectural patterns, and vertical greening systems (green walls and facades) and demonstrate how to apply the framework with a case study from Pingtan Island, China.     

海南土壤中稀土元素含量及分布特征

对海南四种不同母质来源的土壤样品中的稀土元素含量及分布特征进行了研究,结果表明:除砂岩母质外,海南省其它母质的土壤中稀土元素总量都高于全国土壤、世界土壤和地壳中稀土元素的平均含量;各母质类型土壤中Eu亏损明显。花岗岩上发育的土壤中稀土元素含量最高,总量达419.42mg/kg。砂岩和花岗岩上发育的土壤中LREE相对富集。LREE和HREE在不同母质来源的土壤剖面中的富集、迁移等地球化学行为不完全相同,这说明:土壤发育过程中,稀土元素的含量和分布不仅仅和成土过程、气候及其它地球化学因素有关,而且与母质也有重要的关系,母质往往制约着风化成土过程中稀土元素的地球化学行为。     

上海崇明岛农田土壤中多氯联苯的残留特征

在上海崇明岛采集了101个耕层土壤样品,利用GC-μECD测定了8种多氯联苯(PCBs)浓度,并对其进行多元统计分析,探讨了其可能的污染来源.结果表明,样品PCBs浓度范围为n.d.~261ng/g,均值为56.0ng/g,低氯联苯含量和检出率均较高.不同土壤利用方式对PCBs残留量有一定影响,表现为水稻田土壤>大棚蔬菜西瓜田土壤>露天蔬菜西瓜田土壤.主成分分析和相关性研究结果显示,土壤中低氯联苯同系物间相关性较好,污染来源可能为同一类.     

Snowblower injuries in Vermont, 1981–1984

The Vermont Department of Health carried out two studies of snowblower injuries in Vermont during the winters of 1982–1983 and 1983–1984. The first was a case-control study in which we assessed risk factors that predisposed operators to injury during snowblower use. We found 20 persons who had been injured by snowblowers and matched 28 controls to these by neighborhood. In this study, owning a snowblower for 1 year or less and having operated a snowblower for 10 days or less in one's lifetime were significantly associated with injury. The second study was population-based. We estimated that approximately 1.5% of Vermont residents owned snowblowers during the winter of 1982–1983 and that, among snowblower owners, injuries occurred at a rate of 1.3/1,000 person-years of ownership (0.1% chance of injury).     

Risk cognition and the public: The case of Three Mile Island

Residents of within 50 miles of the nuclear power plant at Three Mile Island (TMI), Pennsylvania, were surveyed in 1979, 1980, and 1982 to assess their general attitudes toward nuclear power, to assess their individual coping responses to the March 1979 accident, and to monitor changes in attitudes over the three-year period. Most respondents feel that future accidents like TMI will occur once or twice more in their lifetimes, that operating nuclear power stations should have improved safeguards and should continue operating, and that major institutions—government and utility companies—are experiencing a continued erosion of public trust.     

Freshwater Wetland dynamics in South Kingstown,Rhode Island, 1939–1972

The extent and causes of changes in the fresh-water wetlands of South Kingstown, Rhode Island were determined through field work and through the analysis of panchromatic aerial photographs taken in 1939 and 1972. During this period, there was a net loss of 0.9 percent of the total area (2345.2 ha) of wetland present in 1939. Highway construction and residential development accounted for most of this loss. Approximately 17 percent of the wetland present in 1939 had changed sufficiently by 1972 to warrant reclassification. Plant succession alone accounted for 57 percent of the changes in wetland types, while man's activities were influential in 41 percent of the cases. Ninety-two percent of the natural changes in wetland types was progressive, while 58 percent of the changes induced by man and undetermined causes was retrogressive. Man's major role was to alter the water regimes and vegetation of wetlands. There was a decrease in wetland diversity as the most abundant type, wooded swamp, grew in area while the abundance of shallow marshes, meadows, and shrub swamps declined. A knowledge of wetland dynamics is essential in the management of wetlands for a diversity of wildlife and other natural values.     

旅游区旅游环境容量研究

选择典型的海岛型旅游区——蜈支洲岛旅游区为研究对象,通过分析旅游容量体系,定量研究了该景区的旅游环境容量。研究结果表明,该旅游区的生态环境容量、功能设施容量、空间环境容量和社会环境容量分别为10 400、7 200、8 910和17 000人次/日。功能设施容量和空间环境容量成为制约景区接待规模的限制因子。提出新建和改建基础服务设施、建立淡旺季两套管理措施、新建景点和扩建游步道等措施,来提高蜈支洲岛景区的整体环境容量并缓解旅游旺季带来的环境容量超载问题。     

舟山青浜岛不同环境介质中PAHs的分布特征

于2013年7月在青浜岛上采集11个土壤样品、3个大气被动采样样品以及周边3个海水样品,分析了样品中16种多环芳烃(PAHs)的含量,并对其分布特征、来源、生态风险进行了讨论.结果表明,土壤、海水和大气中Σ16PAHs的含量范围分别为60.30~123.34 ng·g-1(平均值为105.49 ng·g-1)、45.96~101.08 ng·L-1(平均值为66.45 ng·L-1)和5.09~5.41ng·d-1(平均值为5.35 ng·d-1).分布特征为:潮汐带土壤中PAHs含量低于非潮汐带;3个海水样中,以靠近水文条件复杂的海域内样品中的PAHs含量最高;岛上大气中PAHs分布均匀.土壤、海水和大气中PAHs主要以2~4环的PAHs为主;通过比值法和因子分析得出,青浜岛土壤中的PAHs来源于煤、木炭等生物质燃烧以及柴油、汽油的燃烧,海水和大气中的PAHs来源于混合源.生态风险评价结果表明青浜岛土壤和周边海水中PAHs生态风险较低.     

长兴岛邻近海域的沉积物粒度参数特征及物源分析

采用筛分法和吸液法分析长兴岛邻近海域11个表层沉积物样品,获得了1Φ间隔的粒度参数数据。分析结果表明,临港工业区附近海域的沉积物类型主要有G、S、S-T-Y、TS、YS、G-S-T、ST、YT共8种,S和ST是该区的优势和次优势组份。平均粒径在-1~2.623Φ,分选系数在0.221~3.213,偏态在0.311~1.311,峰态在0.828~3.978。基于沉积物各粒级的空间分布规律,对研究区域的物质来源情况,进行了分析讨论。