人口经济与环境整体优化模型初步研究

一个城市在发展中做到人口经济与环境的整体优化，传统的思路是控制人口经济发展。８０年代以来持续发展理论的提出，以产业技术结构的演进，二、三产业的融合来促使人口经济环境由低级向高级发展，取得人口经济与环境的整体优化，这就要求提供实用的研究方法。本文提出人口经济与环境整体优化模型的思路，给出了具体模型的建立方法，讨论各项参数的获取，从而可为城市人口经济与环境整体优化研究奠定基础。     

土地资源对珠三角地区人口增长的约束分析

改革开放以来，随着经济高速发展，大量外来人口涌入珠三角地区。1979─2012年间，珠三角地区的常住人口从1797.42万人增至5681.70万人。大规模的人口增长使得珠三角地区的资源供给压力增大，特别是土地资源。2010年珠三角地区已开发的建设用地面积为8867 km2，其中深圳、东莞等城市的建设用地规模已经接近其土地资源的适宜开发上限，土地资源对人口增长的约束作用也日趋显著。为了评判珠三角地区土地资源压力对人口增长的影响，利用Malthus模型和Logistic模型分别对该地区9个城市的人口变化进行拟合，结果表明，2组模型对2000年前各城市的人口变化均有较高的拟合精度且拟合结果与实际情况较为相近，主要是由于该地区早期发展阶段的资源压力对人口增长的约束作用较小。2000年以后不同城市的Logistic模型与Malthus模型对人口变化预测呈现出不同的趋势，主要与各城市的土地资源压力密切相关。根据2组模型模拟结果的差异和土地资源的压力，将9个城市分为3组。其中深圳、东莞为第一组，这2个城市的人口增速最快、土地资源压力最大，相应的Malthus模型的估计值分别在2003年、2005年超过了实际人口，且其后估计值与实际值的差距逐渐增大。依据Malthus模型2020年深圳、东莞的人口预测值分别为6469.58万人、2386.81万人，这大大超过了这2个城市的资源环境承载极限。这一结果说明在深圳、东莞的人口高速增长已经不可持续，Malthus模型已不能反映其未来人口的变化趋势。第二组包括广州、佛山、珠海和中山4个城市。这组城市的人口增速相对缓慢，Malthus模型的估计值与实际人口较为接近，但2010年以来这4个城市人口的增长呈放缓趋势，Malthus模型估计值逐渐偏大。第三组城市包括人口增速最慢的江门、惠州和肇庆3个城市。这组城市的人口?     

格氏栲种群增长动态预测研究

以”空间推时间,横向导纵向”方法,建立了格氏栲种群标准生命表、生殖力表,在此基础上运用Ｌｅｓｌｉｅ种群增长模型,预测了格氏栲种群的动态增长过程,揭示了格氏栲各龄级植株的动态规律;同时采用特征根理论方法,分析格氏栲种群稳定性,并模拟格氏栲种群的可能变化．结果表明：该区格氏栲为缓慢增长型种群,总体上保持相对稳定状态,老龄阶段对干扰不敏感,种子和生长阶段对干扰有较大敏感．讨论认为,本结果可为格氏栲种群的保护和经营管理提供理论依据和信息     

微型裸腹蚤的生长,生殖和种群增长

年龄为５±２ｈ的纯系微型裸腹蚤置于２５±１℃、主要含斜栅藻的培养液、静置换水的条件下培养时,其体长（ｌｔ）增长模式为ｌｔ＝１．３０－０．７９７６ｅ－０．３６８２ｔ（ｌｔ为体长,ｔ为时间）,各龄蚤平均体长为１．０８ｍｍ,平均寿命为１９．１ｄ,生殖高峰发生在第５龄期,累计生殖量为１０１．２１个．从初始２０个体的种群计算,种群生长曲线呈ｌｏｇｉｓｔｉｃ型：ｙ＝２０２４／（１＋ｅ４．１３６－０．５３７ｔ）（ｙ为总个体数）,内禀增长能力ｒｍ＝０．９８５／ｄ,净生殖率Ｒ０＝８２．２５３／世代,世代平均周期Ｔ＝４．７２ｄ．     

结构方程模型在城市环境管理中的应用

针对城市经济增长与环境污染负荷之间的耦合关系,选取45个样本城市,采用2004年的截面数据,开发了结构方程模型研究环境污染负荷、环境基础设施、土地利用、工业化程度和经济发展5个结构因子之间的关系。结果表明:环境污染负荷与经济发展和环境基础设施建设直接相关,而与土地利用没有明显相关,建议城市管理者应当重点调控环境基础设施、工业化发展等结构因子,以实现城市环境污染负荷的削减目标。     

页岩气开发地块污染物的种群生态风险评估模型分析

页岩气资源气藏结构相对复杂,生态环境相对脆弱,环境影响机理不清等一系列环境问题已成为制约我国页岩气开发的重要瓶颈,目前我国对页岩气开发地块的生态风险评估研究极少,远未能形成技术体系。由于个体之间、个体与环境之间存在相互作用,个体水平的生态风险评估往往无法全面地反映化学污染物质对生态环境的整体影响,因此开展种群层面的生态风险评估对提高其风险准确性具有重要作用。本文在通过聚类分析方法了解种群生态风险评估领域的热点和发展趋势的基础上,借助文献计量方法较系统地梳理了有关种群层面的生态风险评估模型的内容,对比分析并筛选可适用于我国典型页岩气开发区域特征污染物的种群生态风险评估模型并探讨了其在页岩气开发场景的可用性及不确定性,旨在为我国这类污染场地环境风险防控提供借鉴。     

种群水平生态风险评价方法概述及其在环境管理中的应用

生态风险评价的目的是保护生态系统功能的完整性、稳定性和持久性,为环境风险管理提供理论依据。然而,目前常见的用于保护生物的化学污染物浓度阈值大多是以个体水平的毒性试验结果为基础,忽略了物种在时间和空间相互作用等因素,不能够完全保护生态环境安全和生态系统功能的延续性。本文从生态风险评价的概念、目的和意义引出种群水平生态风险评价在环境管理应用的重要性,综述了种群水平生态风险评价的科学问题(如密度依赖、遗传变异和空间结构等),归纳了种群水平风险评价主要模型方法及其应用(如Euler-Lotka方程、预测矩阵、个体模型、空间模型和动态能量预算模型等),列举了各国现有法律法规中关于种群水平生态风险评价的规定,以期为种群水平生态风险评价方法研究及在环境管理中的应用提供有益借鉴。     

广东人口粮食动态模型的建立及土地生产力分析

对我省的人口发展和粮食生产进行了系统的分析和研究,结果表明广东人口将在2005年底达到8000万人,比过去人口的增长速度明显加快;而粮食生产却不容乐观,到2015年最多只能达到年产2670万t的水平,人均粮食约280 kg,比目前水平略低。从长远来考虑,我省的粮食问题将更显不足,而耕地又逐年减少,故提高土地利用率和生产水平是目前迫切需要解决的实际问题。     

3S与在线监测技术在环境模型研究中的应用

结合环境信息系统的研究现状和研究实例，首先分析了3S和在线监测技术与环境模型研究结合的必要性，并分析指出了3S、在线监测技术在环境模型研究中潜在的应用范围，然后剖析了3S技术与环境模型研究结合的三阶水平，最后介绍了3S在环境规划模型研究中的理想结合框架。     

化学品环境暴露评估模型研究进展

各国政府高度重视化学品生产使用引发的环境问题,研发了一系列环境暴露预测模型,包含了点源暴露到面源暴露各种排放模式,局部暴露、区域暴露及洲际暴露的各种预测尺度,筛选评估到确认水平的不同评估层级,用于评估化学品的潜在风险。本文从模型功能、机理出发,综述了化学品环境暴露评估涉及的排放估计、水/土/气、多介质以及食物链评估模型,以期为推动我国化学品环境暴露模型的研发提供参考。     

软约束机制下的生态预算理论的问题及对策

在分权体制框架下,约束机制软化导致地方政府放大其自利性偏好,在一定程度上成为可持续发展的减项。表现为：在当前政府绩效考核的经济指标压力下扩大自然资源的投入;与资源消耗主体博弈的经济人行为导致不规范的环境资源分配,使环境目标和环境管理目标的实现呈现高成本特征;与中央政府相较的信息优势导致全局性的非理性资源的浪费等。生态预算是ICLEI参照财政预算的程序创建的促进环境资源有效配置和可持续管理的政府工具,其以强可持续发展为目标,采用实物指标度量环境资源在社会经济活动中的实际流量,强调约束支出控制,以保持环境资源全部价值在代内和代际间的平衡。我国在引进生态预算监督制约机制的路径选择及模式设计上,可能会出现因现实文化的惯性、双重代理机制、体制内监督等问题导致的生态预算约束软化,改进方向在于重视环境-经济-社会一体化考核的作用、确定合理的激励方式、由社会审计评价和监督生态预算执行,从而逐步走向制度完善的进程。     

Individual based model of slug population and spatial dynamics

The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field within which slug spatial dynamics and changes in abundance were simulated. The strong dependence of slug behaviour on environmental conditions is built into the model, which is based upon previous work on the environmental dependence of slug population dynamics. The simulation results show that the IbM described well changes in the slug population. The IbM proved capable of describing slug populations over 3.5 years, including the presence, magnitude and duration of D. reticulatum population crashes within this period. Moreover, the model was capable of reproducing slug population dynamics at two sites, with distinct weather and some 100 km apart, with minor changes in initialisation values but no change in model structure and parameter values. A study of field heterogeneity, which might simulate various field designs, indicated the importance of spatial structuring to slug population dynamics and the utility of the IbM for simulating a range of potential spatial management treatments for slug control to maximise crop yield. This IbM system performs well and is currently being used as part of an integrated approach to predict slug population dynamics and control in the UK.     

Migration effects in a stochastic multipopulation model for African bee population dynamics

The rate of northern migration of the Africanized honey bee (AHB) in the United States has recently slowed dramatically. This paper investigates the impact of migration on the equilibrium size distributions of a particular stochastic multipopulation model, namely a coupled logistic power law model. The bivariate equilibrium size distribution of the model is derived and illustrated with parameter values used to describe AHB population dynamics. In the model, the difference between the equilibrium sizes of the two populations is a measure of the effect of migration. The distribution of this difference may be approximated by a normal distribution. The mean and variance parameters for the normal are predicted accurately by a second-order regression model based on the migration rate and the maximum size of the first population. The methodology is general, and should be useful in studying the migration effect in many other applications with one-way migration.     

Growth, environment and innovation—a model with production vintages and environmentally oriented research

I develop an innovative environmental new growth model driven by researchers striving for monopoly profits. Skilled labour is allocated between production vintages and two forms of research, ordinary and environmentally oriented. The intermediate sector includes fixed costs and decreasing returns, limiting the number of vintages used. I solve for planner's, laissez-faire, and regulator's solutions, and examine welfare implications and the various distortions in the model (monopoly power, knowledge spillovers, business stealing, environmental externalities). A regulator may wish: (i) to encourage environmentally oriented research; (ii) to concentrate production labour on recent (cleaner) vintages; (iii) to switch labour from production to research. An environmental sales tax may under some circumstances achieve all three—such taxes not only give incentives to reduce pollution, but also shift profits from old vintages to new, thus raising incentives to come up with newer (cleaner) vintages. An environmental tax may even lead to an increase in the rate of production growth.     

VA菌根真菌对玉米生长及根际土壤微生态环境的影响

用两种不同的VA菌根真菌Glomus mosseae和Glomuscaledonium接种玉米进行盆栽试验。结果表明,两种菌株均能侵染玉米,促进玉米生长．其中以Glomus caledonium的侵染率和作用较为明显。接种后,根区土壤中的细菌、放线菌、固氮菌的数量和微生物生物量明显增加,但真菌的数量则稍有下降。此外．菌根的形成也改善了根区土壤的微生态环境,为下一造作物的生长积累了养分基础。     

Demographic Processes Underlying Population Growth and Decline in Salamandra salamandra

Abstract:  Human activity commonly has negative impacts on wildlife. Often, however, only a single element of the life cycle is affected, and it is unclear whether such effects translate into effects on population growth. This is particularly true for research into the causes of global amphibian declines, where experimental research focuses primarily on the aquatic larval stages but theory suggests these stages have only minor importance for population growth. We used data from long-term mark-recapture studies of two natural populations of the salamander Salamandra salamandra to confirm the predictions of population models. One population remained stable (i.e., stationary) throughout the 20 years of the study whereas the other declined to local extinction. We used mark-recapture models to break down population growth rate into its two main components, recruitment and adult survival. Survival of postmetamorphic salamanders was constant over time in the stable population, whereas the declining population was characterized by a decrease in survival and constant recruitment. Population growth was most sensitive to variation in adult survival. Current amphibian research focuses on preadult stages, and researchers assume recruitment is the most important determinant of population growth. This may not be the case. A better understanding of amphibian population dynamics is possible only through the integration of experiments, theory, and data from natural populations. Our results also suggest that amphibian conservation efforts should focus on all stages of the life cycle and their associated habitats.     

Selecting parameters for calibration via sensitivity analysis: An individual-based model of mosquitofish population dynamics

A stochastic individual-based model (IBM) of mosquitofish population dynamics in experimental ponds was constructed in order to increase, virtually, the number of replicates of control populations in an ecotoxicology trial, and thus to increase the statistical power of the experiments. In this context, great importance had to be paid to model calibration as this conditions the use of the model as a reference for statistical comparisons. Accordingly, model calibration required that both mean behaviour and variability behaviour of the model were in accordance with real data. Currently, identifying parameter values from observed data is still an open issue for IBMs, especially when the parameter space is large. Our model included 41 parameters: 30 driving the model expectancy and 11 driving the model variability. Under these conditions, the use of “Latin hypercube” sampling would most probably have “missed” some important combinations of parameter values. Therefore, complete factorial design was preferred. Unfortunately, due to the constraints of the computational capacity, cost-acceptable “complete designs” were limited to no more than nine parameters, the calibration question becoming a parameter selection question. In this study, successive “complete designs” were conducted with different sets of parameters and different parameter values, in order to progressively narrow the parameter space. For each “complete design”, the selection of a maximum of nine parameters and their respective n values was carefully guided by sensitivity analysis. Sensitivity analysis was decisive in selecting parameters that were both influential and likely to have strong interactions. According to this strategy, the model of mosquitofish population dynamics was calibrated on real data from two different years of experiments, and validated on real data from another independent year. This model includes two categories of agents; fish and their living environment. Fish agents have four main processes: growth, survival, puberty and reproduction. The outputs of the model are the length frequency distribution of the population and the 16 scalar variables describing the fish populations. In this study, the length frequency distribution was parameterized by 10 scalars in order to be able to perform calibration. The recently suggested notion of “probabilistic distribution of the distributions” was also applied to our case study, and was shown to be very promising for comparing length frequency distributions (as such).     

Mountain environment and population in Georgia: case study of Upper Svaneti

The purpose of the presented research is to identify local community opinions toward ecological problems in one of the mountainous region of Georgia (Upper Svaneti), to analyze how population ‘perceive, experience, and interpret’ the social, and ecological issues.

The paper is based on the results of Upper Svanet ipopulation’s survey which was carried out by the authors of presented paper during the August of 2015 and 2016.The questionnaire was elaborated taking into account the peculiarities of the region. Stratified-cluster selection method was used for selection of respondents and database compilation. For statistical analysis of polling data the SPSS package was used.

Based on the statistical analysis of survey results, the following issues have been studied: the most important ecological problems, environmental problems with respect to socio-economic ones, information sources on ecological problems, people’s trust in environmental issues, awareness level of the population on environmental policy, their personal contribution in environmental protection, ways to solve ecological problems, implemented environmental measures.

The obtained results are important to foster mountain population’s active participation in processes that contribute to decision-making processes, planning and implementing programs for sustainable development.     

基于遥感技术的太湖放养凤眼莲的生长模型

根据从卫星遥感影像或全球定位系统获得的凤眼莲面积变化数据,对在开放水域中大面积放养凤眼莲面积变化的研究,建立了放养凤眼莲生长的Logistic动力学模型来估算凤眼莲面积。在太湖竺山湾凤眼莲放养试验表明：从2009年8月4日到10月15日,凤眼莲面积从54 250.34 m2增加到135 525.66 m2,建立的估计凤眼莲面积的Logistic模型的环境容量k s为2 697 210.03,面积增长率rs为0.012 4,对试验数据的拟合优度检验R 2为0.975 3,F检验为78.93,均方根误差RMSE为2 705.55,表明该模型准确模拟了凤眼莲生长的动力学特征。     

Harvesting the sun: New estimations of the maximum population of planet Earth

The maximum population, also called Earth's carrying capacity, is the maximum number of people that can live on the food and other resources available on planet Earth. Previous investigations estimated the maximum carrying capacity as large as about 1 trillion people under the assumption that photosynthesis is the limiting process. Here we use a present state-of-the-art dynamic global vegetation model with managed planetary land surface, Lund-Potsdam-Jena managed Land (LPJmL), to calculate the yields of the most productive crops on a global 0.5° × 0.5° grid. Using the 2005 crop distribution the model predicts total harvested calories that are sufficient for the nutrition of 11.4 billion people. We define scenarios where humankind uses the whole land area for agriculture, saves the rain forests and the boreal evergreen forests or cultivates only pasture to feed animals. Every scenario is run in an extreme version with no allowance for urban and recreational needs and in two soft versions with a certain area per person for non-agricultural use. We find that there are natural limits of the maximum carrying capacity which are independent of any increase in agricultural productivity, if non-agricultural land use is accounted for. Using all land planet Earth can sustain 282 billion people. The save-forests-scenario yields 150 billion people. The scenario that cultivates only pasture to feed animals yields 96 billion people. Nevertheless, we should always have in mind that all our calculated numbers for the carrying capacity refer to extreme scenarios where humankind may only vegetate on this planet. Our numbers are considerably higher than the general median estimate of upper bounds of human population found in the literature in the order of 10 billion.