Tolerance of Birch Stands of the Northern Transural Forest Steppe to Abiotic and Biotic Stress Factors

It is shown that both diffuse and complete drying of birch stands is due to the additive effects of meteorological factors (hydrothermal parameters of the first and second halves of the growing period) and tree defoliation by phyllophagous insects, with the former being of primary importance.     

Brownfield redevelopment as a smart growth option in the United States

An evaluation is made of brownfields redevelopment as a smart growth policy compared to purchase of land, restrictive growth policies, changing transportation patterns, promoting compact development designs on the metropolitan fringe, and regional government. In the US brownfields redevelopment has clear advantages with regard to environmental protection, moral imperative, and government and special interest reactions. Its rank with regard to economic feasibility, ability to respond to changes in technology, and public reaction are not clear. A great deal more research is needed, especially about the costs of brownfield redevelopment and public preferences for housing type and location to be certain about brownfields redevelopment as a viable smart growth option.     

环境因子对红斑顠体虫生长的影响

讨论了环境中氨氮的浓度、pH值、盐度、温度对红斑顠体虫生长的影响.结果表明,在pH值为7时,氨氮对红斑顠体虫的急性毒性半致死浓度为264mg/L;红斑顠体虫对氨氮长期接触时的最大可接受浓度在20～50mg/L;氨氮对红斑顠体虫的毒性随pH值的增加而增加;盐度在1000mg/L以下,对红斑顠体虫的死亡没有影响;温度在15～30℃,红斑顠体虫的表观增长速率满足Arrhenius拟合,其表观增长率随温度增加而增大,但35℃时红斑顠体虫的生长减缓.     

长期定位施肥田土壤酶活性的动态变化特征

为探讨长期施肥条件下玉米生育期内土壤酶活性的动态变化及其与土壤肥力的关系,该文对北京褐潮土定位试验田第12年的土壤酶以及土壤养分因子进行了测定和分析.结果表明.土壤过氧化氢酶、磷酸酶在玉米拔节期出现活性高峰.土壤脲酶在玉米拔节期及成熟期出现两个活性高峰,土壤蔗糖酶在整个玉米生育期内活性变化幅度较小.长期施肥能明显提高土壤中蔗糖酶、脲酶、磷酸酶活性,其中有机肥与化肥配施对于增加土壤中蔗糖酶、脲酶、磷酸酶活性尤为显著.长期施肥降低土壤中过氧化氢酶活性.并且以NPK配施有机肥处理的土壤过氧化氢酶活性降低幅度最大.土壤酶之问及其与土壤养分因子之间具有明显相关性,其中蔗糖酶、脲酶及磷酸酶与土壤养分各因子均呈显著或极显著正相关,除碱解氮外,过氧化氢酶与其余各养分因子呈显著或极显著负相关.     

阿特拉津对铜绿微囊藻和四尾栅藻生长的影响

在实验室内利用MA培养液培养,通过测定藻生长量和叶绿素a含量,研究不同浓度下的阿特拉津对铜绿微囊藻(Microcystis aeruginosa)和四尾栅藻(Scenedesmus quadricauda)生长的影响,并以藻细胞数表示的最大比生长率为指标,评价2种藻对阿特拉津的敏感性.结果表明,在0.001～5.000 mg·L-1质量浓度范围内,阿特拉津对铜绿微囊藻和四尾栅藻的生长表现出低浓度刺激、高浓度抑制的效应,且阿特拉津对四尾栅藻的刺激效应明显大于铜绿微囊藻.     

20世纪下半叶上海市居住用地扩展模式、强度及空间分异特征

基于多时相土地利用图与遥感影像资料,建立空间研究网格,通过土地利用扩展强度指数的空间分析,对1947～2002年上海市建成区居住用地扩展模式、强度及空间分异特征进行了研究。结果表明:①上海市建成区居住用地空间扩展并不是持续增长的,其扩展强度与速度均从建国初期开始减小,在1964～1979年期间达到最低值后又逐渐增大,总体上表现为先降后升的发展变化;②居住用地扩展模式随时间发生较大变化,由建国初期以核心建成区为主的渐进式扩展(1947～1964年)转变为跳跃式扩展(1964～1988年),到近些年又发展成兼具渐进扩展与跳跃扩展特征的混合扩展模式(1988～2002年),城市用地功能由简单趋于复杂和多元化;③不同时期居住用地扩展过程差异较大,其行为特征受国家宏观政策及社会经济发展等因素的影响,可以为复杂的城市扩展动力机制研究提供更多素材。     

厦门海域春夏季微型浮游动物对浮游植物的摄食压力初探

应用稀释法对厦门海域浮游植物生长率(k)和微型浮游动物的摄食率(g)进行了估算。结果显示：5月,西海域18测站k、g分别为2．41、0．78d^-1;南部海域27测站分别为2．43、1．32d^-1。8月18测站k、g分别为3．00、2．90d^-1;27测站分别为1．94、0．91d^-1。说明厦门海域作为典型的亚热带港湾,具有高的k、g值。分粒级研究结果显示：8月,18测站微型浮游动物对微型浮游植物(Micro)具摄食偏好;而27测站微型浮游动物对Micro和Nano级的摄食率相近。应用流式细胞技术研究18测站微微型真核浮游植物的k、g,结果表明：春季,生长率和摄食率分别为2．00、1．02d^-1;夏季分别为1．52、0．96d^-1。     

A meta‐analysis of functional group responses to forest recovery outside of the tropics

Both active and passive forest restoration schemes are used in degraded landscapes across the world to enhance biodiversity and ecosystem service provision. Restoration is increasingly also being implemented in biodiversity offset schemes as compensation for loss of natural habitat to anthropogenic development. This has raised concerns about the value of replacing old‐growth forest with plantations, motivating research on biodiversity recovery as forest stands age. Functional diversity is now advocated as a key metric for restoration success, yet it has received little analytical attention to date. We conducted a meta‐analysis of 90 studies that measured differences in species richness for functional groups of fungi, lichens, and beetles between old‐growth control and planted or secondary treatment forests in temperate, boreal, and Mediterranean regions. We identified functional‐group–specific relationships in the response of species richness to stand age after forest disturbance. Ectomycorrhizal fungi averaged 90 years for recovery to old‐growth values (between 45 years and unrecoverable at 95% prediction limits), and epiphytic lichens took 180 years to reach 90% of old‐growth values (between 140 years and never for recovery to old‐growth values at 95% prediction limits). Non‐saproxylic beetle richness, in contrast, decreased as stand age of broadleaved forests increased. The slow recovery by some functional groups essential to ecosystem functioning makes old‐growth forest an effectively irreplaceable biodiversity resource that should be exempt from biodiversity offsetting initiatives.     

Population Growth,Available Resources,and Quality of Life:China’s Post-Reform Economic Development

Two opposing intellectual traditions and their contem-porary developments regarding the relations among population, available resources, and quality of life as reflected in economic growth are reviewed. What is at issue is whether population growth is detrimental to or beneficial for economic development. Neither of the extreme views gives a complete picture of the interplay among population, resources, and quality of life. Following previous literature on the topic, this paper establishes a more balanced approach that considers the function linking population and quality of life not constant but variable and regards the limitedness of resources as not absolute but relative to regions and societies. The proposed approach is more flexible in better explaining the relation between population and economic growth. China is examined as a case in point to shed light on the interaction of population growth, economic development, and available resources, and its recent post-economic reform experiences showcase the appropriateness of the synthetic approach.     

企业安全生产标准化体系的成长性态诊断

为了诊断企业安全生产标准化体系成长性态,将安全生产标准化内化为企业的安全管理方法,基于过程管理的基本理论,按照行为特性与工作流程,从策划行为域、实施行为域、可信度行为域3个层次界定安全生产标准化的体系结构;其次,从成熟度级别、共同特性和通用活动3个构成要素划分成长性态层次结构;然后,将安全生产标准化的体系结构和成长性态层次标识为企业安全生产标准化水平的二维结构,提出基于模糊区间的安全生产标准化体系成长性态诊断方法.结果表明,调查企业的安全生产标准化体系成长性态诊断结果位于规范级,但存在不平衡问题,在评估与确立安全目标、安全培训、细化安全目标要求、交底与配备资源和可信度论据等方面诊断值较低,需要加以改进.