新疆中部天山雪岭云杉种群动态初步研究

雪岭云杉PiceaschrenkianaFisch.etMey在中部天山林区内分布于海拔1500m～2700m之间,形成一个垂直分布带。作者采用样方法进行调查,沿海拔梯度每隔100m选取两块样地(20m×20m),在海拔1500～2700m的雪岭云杉林内共选样地26块来调查中部天山雪岭云杉种群的年龄结构、密度和生物量动态。在所选样地内,调查所有雪岭云杉树木(h≥2m)的胸径并按5cm分成不同的径级,每一径级至少选取两棵树,每棵树在不同方向上钻取两个树芯,建立年龄-胸径方程推算样地内所有雪岭云杉树(h≥2m)的年龄;调查样地内所有幼苗(h<50cm)和幼树(50cm≤h<200cm)的高度并根据主干上轮枝数查数一定数目幼苗幼树的年龄,建立年龄-高度方程并推算样地内所有幼苗幼树的年龄。研究结果表明中部天山雪岭云杉种群的胸径、年龄结构和种群密度都呈倒-J型分布,种群生物量呈钟型分布,存活曲线基本介于DeeveyⅡ和DeeveyⅢ型之间。以上研究结果表明中部天山的雪岭云杉种群处于不断更新和稳定发展的时期。     

Taxonomic Considerations in Listing Subspecies Under the U.S. Endangered Species Act

Abstract:  The U.S. Endangered Species Act (ESA) allows listing of subspecies and other groupings below the rank of species. This provides the U.S. Fish and Wildlife Service and the National Marine Fisheries Service with a means to target the most critical unit in need of conservation. Although roughly one-quarter of listed taxa are subspecies, these management agencies are hindered by uncertainties about taxonomic standards during listing or delisting activities. In a review of taxonomic publications and societies, we found few subspecies lists and none that stated standardized criteria for determining subspecific taxa. Lack of criteria is attributed to a centuries-old debate over species and subspecies concepts. Nevertheless, the critical need to resolve this debate for ESA listings led us to propose that minimal biological criteria to define disjunct subspecies (legally or taxonomically) should include the discreteness and significance criteria of distinct population segments (as defined under the ESA). Our subspecies criteria are in stark contrast to that proposed by supporters of the phylogenetic species concept and provide a clear distinction between species and subspecies. Efforts to eliminate or reduce ambiguity associated with subspecies-level classifications will assist with ESA listing decisions. Thus, we urge professional taxonomic societies to publish and periodically update peer-reviewed species and subspecies lists. This effort must be paralleled throughout the world for efficient taxonomic conservation to take place.     

Reliability of Absolute and Relative Predictions of Population Persistence Based on Time Series

Abstract:  Conventional population viability analysis (PVA) is often impractical because data are scarce for many threatened species. For this reason, simple count-based models are being advocated. The simplest of these models requires nothing more than a time series of abundance estimates, from which variance and autocorrelation in growth rate are estimated and predictions of population persistence are generated. What remains unclear, however, is how many years of data are needed to generate reliable estimates of these parameters and hence reliable predictions of persistence. By analyzing published and simulated time series, we show that several decades of data are needed. Predictions based on short time series were very unreliable mainly because limited data yielded biased, unreliable estimates of variance in growth rate, especially when growth rate was strongly autocorrelated. More optimistically, our results suggest that count-based PVA is sometimes useful for relative risk assessment (i.e., for ranking populations by extinction risk), even when time series are only a decade long. However, some conditions consistently lead to backward rankings. We explored the limited conditions under which simple count-based PVA may be useful for relative risk assessment.     

Duck Populations as Indicators of Landscape Condition in the Prairie Pothole Region

The Prairie Pothole Region of the northern GreatPlains is an important region for waterfowl production becauseof the abundance of shallow wetlands. The ecologicalsignificance of the region and impacts from intensiveagriculture prompted the U.S. Environmental Protection Agency to select it as one ofthe first areas for developing and evaluating ecologicalindicators of wetland condition. We examined hypothesizedrelations between indicators of landscape and wetlandconditions and waterfowl abundance on 45 40 km² study sites in North Dakota for1995–1996. Landscape condition was defined a priori as the ratio of cropland area to total upland area surroundingwetlands. Measures of waterfowl abundance included estimatednumbers of breeding pairs (by species and total numbers) and , a species-specific correction factor which effectively adjusts breedingpair estimates for annual or area-related differences in pondsize. Landscape indicators and waterfowl measures varied among regions. Results indicated that most areas in the Coteau region are ofmuch higher quality for ducks than those in the Drift Plain,and areas in the Red River Valley are of the poorest qualityfor ducks. Regression models demonstrated the impact ofagricultural development on breeding duck populations in the PrairiePothole Region. The most consistent landscape indicators ofwaterfowl abundance were percent of cropland and grassland. Models were inconsistent among years and species. Thepotential biotic indicators of landscape and wetland condition examined here wouldbe appropriate for temporal trend analyses, but because ofinherent geographic variability would not be appropriate forsingle-year geographic trend analyses without more extensiveevaluations to improve explanatory models.     

Review of environmental monitoring methods: survey designs

During the past decade and a half, environmental monitoring programshave increased in numberand importance. Large scale environmental monitoring programs often present design difficulties because they tend to measure many(sometimes hundreds) of parameters through space and time. Thispaper reviewed and summarized one important component of environmental monitoring programs, the statistical survey design. Survey designsused for long-term monitoring programs lasting multiple (3)occasions were reviewed, paying specialattention to those published after 1985. During this review, two key components of the overall survey design were identified. The first key component wasthe membership design. Groups of population units sampled the same occasionwere called panels here, and the membership design specified which units were members of which panels. The second component was the revisit design that specified when panels were to be revisited. Membership designs varied, butsome form of simple random or systematic design was popular.Among revisit designs, four basicpatterns were found in the literature and their relative strengths andweaknesses were summarized. To efficiently discuss revisit designs, anew unified short-hand notation was proposed and adopted.     

2015年厄尔尼诺年东南亚主要国家活跃火发生类型与影响分析

2015年强厄尔尼诺引起东南亚干旱少雨与活跃火加剧,但目前有关活跃火时空特征、发生类型与强度及其对人口—社会经济影响仍分析不足。利用美国国家航空航天局火灾信息资源管理系统（FIRMS）VIIRS V1活跃火位置矢量产品,通过月际、地形、土地覆被类型等GIS分析确定东南亚主要国家活跃火主要类型,并评价各国活跃火对人口分布的影响范围与国别差异。结果表明：（1）东南亚2015年活跃火发生频次达81.40×10⁵次,中南半岛与马来群岛各占69.60%与30.40%,分别集中发生在2-4月与8-10月,各国活跃火频次与发生时间差异很大。（2）中南半岛五国活跃火地形差异明显,缅甸和越南活跃火集中分布于25 m以下;老挝（85~105 m、140~200 m）、泰国（5~15 m、70~110 m）和柬埔寨（5~15 m、70~110 m）活跃火随海拔呈双峰特征;马来群岛国家（印度尼西亚、马来西亚与菲律宾）活跃火集中分布于60 m以下的平原地带;且东南亚35%以上的活跃火均集中分布5~15°的斜坡。（3）东南亚森林、农田活跃火发生率为76%,其中森林活跃火发生率由柬埔寨的52.00%到老挝的74.27%不等,农田活跃火由老挝的13.18%到泰国的42.68%不等。（4）综合活跃火发生月份、海拔、坡度与覆被特征,可从山区刀耕火种农业与平原秸秆焚烧界定东南亚主要国家活跃火发生类型。（5）东南亚活跃火随人口密度增加呈先增后减至平稳变化的趋势,且多集中于人口稀少的乡村和原始森林,其中缅甸、泰国、越南三国有10%以上的活跃火发生在人口密度为72~91人/km²的区域,而马来西亚、老挝、柬埔寨、印度尼西亚30%以上的活跃火集中发生于人口密度在20人/km²以下的区域。     

空调通风管道中细颗粒物凝并规律研究

基于颗粒群平衡模型和布朗扩散作用对空调通风管道中细颗粒物的凝并规律进行了研究。通过对不同入口处细颗粒物的体积分数和入口风速对细颗粒物凝并现象的数值模拟分析,得到的主要结论为细颗粒物的体积分数和入口风速对于管道中细颗粒物的凝并具有显著影响。在布朗扩散作用下的细颗粒物凝并现象主要发生在粒径小于1μm的颗粒,当粒径大于1μm时,布朗扩散作用对于颗粒的凝并无明显影响。     

基于风险的有害物品运输的线路选择分析

为了选择风险尽量小的线路来运输有害物品,减小在运输此类物质时对道路两侧人口带来的风险,通过比较分析,在选择Gaussian模型基础上,将有害物品泄漏后果的概率函数法与人口的风险描述方法相结合,并根据运输中对风险标准的不同要求,结合实际运输过程中可供选择的不同线路的实际情况,得到一次运输中选择不同线路时所产生的相异风险值,从而为有害物品运输中如何通过最小化运输过程中的人口风险来选择线路提供了依据。通过算例分析,得到的结果与使用其它分析性工具得到的结论一致,但结果精确性更高,表明研究结果有很好的实用性,能对实际生产中避免因有害物品运输而带来重大事故有一定指导作用。     

新疆伊犁地区土地资源生产力及人口承载量的初步研究

本文在分析伊犁地区农业自然资源特点和合理用地结构的基础上,预测不同时期一定生产条件下,单位面积土地上粮食,油料肉类的生产潜力和不同生活水平下所承载的人口数量。     

ECONOMIC FORECASTING FOR VIRGINIA'S WATER RESOURCE PROGRAMS1

ABSTRACT: Water resource and water quality management planning depend, to a large degree, on forecasts of industrial activity and population projections. A flexible economic data base is especially important where planning follows varying formats of geographical and industrial detail. Records of employment and payroll are collected in the administration of Unemployment Insurance (U.I.) programs and are available from State Employment Agencies. These statistics have been collected over a long period of record (thirty-five years). Many years of record are available on punched-cards or magnetic tape and may be arrayed and manipulated by computer. This basic approach has been followed in Virginia. Historical U.I. payroll and employment records for the period 1956 through 1970 were procured on magnetic tape. This data was arrayed by major hydrologic area and by regional planning district. Projections of manufacturing activity were then generated by fitting several exponential equations to annual payroll data in two-digit Standard Industrial Classifications. These exponentials were then extrapolated to provide a range of industrial projections. Other parameters of manufacturing activity were then correlated to the payroll data to generate projections of indexes such as employment, value-added, and gross manufacturing output. U.I. payroll data is now being correlated to parameters in non-manufacturing categories. Projections for industries such as trade and services will link extrapolated payroll data with benchmark correlations of payroll and sales receipts.