城乡空间生态规划理论框架试析

初步建构城乡空间规划理论的目标导向、规划要素、规划内容、方法论、编制程序等理论框架,并对其与其它规划的关系进行探讨,认为城乡空间生态规划是城市规划学科生态化的表现之一,这一新的规划理论创新不仅是可能的,而且是必要的。

生态友好型可持续性设计方法研究

支持可持续性用户行为的设计方法最早应用于产品,并逐渐扩展到用户和社会环境。这些方法包含为系统设计有效的功能或约束。虽然许多基于约束的方法可以限定用户的行为,但是通过提供信息和反馈来说服用户改变其态度更为有效。为了激励持续不断的行为改变,意识的内化和对生态友好型行为的认知是至关重要的一步。通过内化的生态友好型意识可以由社会环境来形成。社会环境是指人与人、人与产品之间的关系。通过了解社会环境的形成过程和意义,寻找可持续的生态友好型设计方法,这一点很重要。本研究剖析了不同的生态友好型设计方法,并对每种方法的可行性进行评估,探索通过设计激发可持续性用户行为。

干旱半干旱区草原灌丛化研究进展

干旱半干旱区草原生态系统中原生灌木/木本植物的植株密度、盖度和生物量增加的现象称为草原灌丛化,是全球干旱半干旱区草原面临的重要生态问题,灌丛化研究正成为陆地生态系统全球变化研究的重要领域。引起灌丛化的因素包括过度放牧、草原火、气候变化、大气CO2浓度升高及生物和非生物环境因子的变化等,灌丛化是多种因素共同作用的结果。灌丛化过程表现为地表景观由草本植物占优势转向灌木植物占优势的植被转变过程,此过程改变了原有植物群落的物种组成和结构,增强了地表景观异质性,打破了原生态系统的光照、热量、水分、养分等的分配格局,灌丛斑块成为了灌丛化草地中水分、养分等相对富集的"肥岛"。目前灌丛化研究主要集中在具有强烈地域性和限制性的定点研究和因子控制实验等方面,未来应更多关注气候变化与灌丛化的相互联系和影响、草地生态系统对灌丛化过程的反馈以及与灌丛化的监测、缓解措施等方面的研究,模型模拟将是今后研究灌丛化发生、发展及灌丛化生态系统演替的重要方法和途径。

Feedback Control for Ecosystem Management:The Case of Wolf-Elk-Hunting Dynamics in the US Mountain West

The purpose of this paper is to explore the promise of utilizing some relatively new feedback control techniques in ecosystem management. First, we set forth a basic ecological-economic model of a predator-prey-hunting system in which both the predator and prey have use(flow) and non-use(stock) value and when the predator can inflict transboundary damages. We then use new data from the US Mountain West to show how a particular feedback approach—linear parameter-varying(LPV) control—can be utilized in this context. Our LPV model is able to quantify the cost of managing disturbances that inevitably arise as a manager tries to keep the actual path of the system "close" to its optimum. The results suggest management strategies in mountain ecosystems that feature large, mammalian carnivores.

生态视角下非物质文化遗产的生存斗争与适应性变异

基于生态理念和方法,提出非物质文化遗产(简称"非遗")生态系统,结合非遗"活态"特性与生态学规律,探究非遗内在发展秩序。将众多非遗个体、社会需求、自然条件和生产力水平等因素,作为一个相互联系和影响的整合系统进行研究。通过"生存环境选择"机制,分析该生态系统内部普遍存在的生存斗争与反馈行为。基于非遗的适应性变异和生存斗争,解释非遗生态系统循环更新规律,系统探讨非遗活态生存过程中的一些关键性问题。

Research Progress on Ecological Risk Assessment based on M ultifunctional Landscape

The unreasonable utilization and trade-offs of the multifunctional landscape is one of the important causes leading to ecological risk.Quantifying the relationship,heterogeneous process and driving mechanism between landscape function and human well-being can provide a scientific basis for achieving a win-win situation of regional development and ecological protection,and it is also an important issue for relevant scientific research.In this paper,we reviewed the current state of knowledge regarding landscape function and ecological risk,identified the feedback mechanisms among landscape change,landscape function,human well-being and ecological risk,constructed the ecological risk assessment framework based on landscape functions,and sorted out the key scientific issues and research trends.The interconnections between the multifunctional landscape,human well-being,and ecological risk comprise an important scientific issue in ecological risk assessment.However,there is a lack of understanding of the spatial-temporal characteristics of landscape function trade-offs,and there is also a lack of systematic and standardized methods for the identification and comprehensive evaluation of landscape functions.Exploring ecological risk management and the methodologies that integrate the two processes of nature and humanity is an inevitable trend for future research.Coupling landscape structure,function and process into ecological risk assessment,as well as focusing on the combination of human well-being,landscape function trade-off and ecological risk control policy design are important issues to be studied.

STATE FEEDBACK STABILIZATION FOR A CLASS OF NONLINEAR TIME-DELAY SYSTEMS VIA DYNAMIC LINEAR CONTROLLERS

The dynamic linear state feedback control problem is addressed for a class of nonlinear systems subject to time-delay.First,using the dynamic change of coordinates,the problem of global state feedback stabilization is solved for a class of time-delay systems under a type of nonhomogeneous growth conditions.With the aid of an appropriate Lyapunov-Krasovskii functional and the adaptive strategy used in coordinates,the closed-loop system can be globally asymptotically stabilized by the dynamic linear state feedback controller.The growth condition in perturbations are more general than that in the existing results.The correctness of the theoretical results are illustrated with an academic simulation example.

DYNAMICAL ANALYSIS AND CONTROL IN A DELAYED DIFFERENTIAL-ALGEBRAIC BIO-ECONOMIC MODEL WITH STAGE STRUCTURE AND DIFFUSION

Nowadays, biological resource in prey-predator ecosystem is commercially harvested and sold with aim of achieving economic interest. Furthermore, harvest effort is usually influ- enced by variation of economic interest of harvesting and spatial heterogeneous environ- ment. In this paper, a delayed differential-algebraic bio-economic model is proposed, which is utilized to investigate interaction and coexistence mechanism of biological pop- ulation in the harvested ecosystem due to the variation of economic interest of harvesting as well as the change of population spatial diffusion and gestation delay. Local stability analysis of the proposed model without gestation delay and diffusion reveals that there is a phenomenon of singularity induced bifurcation due to the variation of economic interest of harvesting, and state feedback controllers are designed to stabilize the pro- posed model at the interior equilibrium. Furthermore, local stability of the proposed model with gestation delay and diffusion is studied, which reveals that the interior equi- librium loses its stability at some critical values of gestation delay and corresponding cycle occurs. It is also shown that population spatial diffusion and harvesting have a stabilizing effect on population dynamics. Finally, numerical simulations are carried out to show consistency with theoretical analysis obtained in this paper.

An invading annual plant benefits less from soil biota and has reduced competitive power with a resident grass

Aims Interactions between plants and their soil biota,arbuscular mycorrhizal fungi(AMF)in particular,may play a vital role in the establishment and the range expansion of exotic plants in new environments.However,whether there are post-introduction shifts in dependence on AMF and how dependency interacts with competition remains poorly understood.Methods We conducted a common garden greenhouse experiment to examine how native(USA)and invasive(China)populations of the plant species Plantago virginica,respond to soil biota,and whether these responses change in the presence of a competitor.Important Findings We found that while native populations consistently had a higher AMF colonization rate and benefited from AMF in both biomass and seed production,invasive populations received less benefit from AMF,and even showed reduced biomass with AMF in the presence of a competitor.This low mycorrhizal dependency in invasive populations correlated with greater suppression by an indigenous competitor for the invader.The different responses of the invasive and native populations to AMF suggest that alteration of mycorrhizal dependency has occurred during the invasion of P.virginica into China.Our findings suggest that this reduced dependency incurs a cost during interspecific competition.