A critical appraisal of population viability analysis

Population viability analysis (PVA) is useful in management of imperiled species. Applications range from research design, threat assessment, and development of management frameworks. Given the importance of PVAs, it is essential that they be rigorous and adhere to widely accepted guidelines; however, the quality of published PVAs is rarely assessed. We evaluated the quality of 160 PVAs of 144 species of birds and mammals published in peer-reviewed journals from 1990 to 2017. We hypothesized that PVA quality would be lower with generic programs than with custom-built programs; be higher for those developed for imperiled species; change over time; and be higher for those published in journals with high impact factors (IFs). Each included study was evaluated based on answers to an evaluation framework containing 32 questions reflecting whether and to what extent the PVA study adhered to published PVA guidelines or contained important PVA components. All measures of PVA quality were generally lower for studies based on generic programs. Conservation status of the species did not affect any measure of PVA quality, but PVAs published in high IF journals were of higher quality. Quality generally declined over time, suggesting the quantitative literacy of PVA practitioners has not increased over time or that PVAs developed by unskilled users are being published in peer-reviewed journals. Only 18.1% of studies were of high quality (score >75%), which is troubling because poor-quality PVAs could misinform conservation decisions. We call for increased scrutiny of PVAs by journal editors and reviewers. Our evaluation framework can be used for this purpose. Because poor-quality PVAs continue to be published, we recommend caution while using PVA results in conservation decision making without thoroughly assessing the PVA quality.     

分布式能量系统在我国未来20年能源发展战略中的地位

为了使分布式能量系统（Distributed Energy System,简称DES）在我国更好地发展，本文从我国未来20年的能源发展战略出发，介绍了我国能源发展中依然存在的矛盾和问题，并通过对分布式能量系统组成、特点的研究，认为目前正是分布式能量系统发展的良好机遇：通过对分布式能量系统利用方式的研究，指出了分布式能量系统将在我国未来20年能源发展战略中的地位以及需要解决的相关问题。     

虚拟水战略:拯救民勤绿洲的新思路

位于甘肃石羊河下游的民绿洲，水资源极度缺乏，生产、生活和生态用水矛盾突出，出现了严重的生态危机，其中湖区的生态经济系统已呈“崩溃”之势。拯救民勤绿洲成为社会广泛关注的重大问题。“虚拟水”是20世纪90年代初Tony Allan提出的一个新概念，虚拟水战略是指贫水区域通过贸易的方式从富水地区购进水资源密集型产品来获得本区水资源安全的一种构想。本文通过对节水、调水、移民等常规方案与虚拟水战略的对比分析后，认为虚拟水战略是拯救民勤绿洲的一个全新思路，探讨了虚拟水战略实施的政策建议；提出了创新区域水资源管理体制和区域经济发展思路以及建立国家生态补偿机制的主张。     

Problems and Strategies of Industrial Transformation of China's Resource-based Cities

Resource-based cities face vital economic, social, and environmental problems during their industrial transformation. Urban industrial structure is a traditional primary industrial pattern, which is resource-based and resource-intensive economy with low level technology and efficiency. They encounter tremendous pressure of unemployment and social security. Resources of such cities are on the verge of extinction, in addition, the environmental pollution and ecological conditions are becoming worse. The cities have significant institutional issues and their innovation capacity is inadequate. Therefore, it is necessary to carry out strategic innovations to realize the successful economic transformation of resource-based cities. The strategic innovations include innovation of development goals, equalization of social welfare, sustainable economic development, coordinative development between eco-environment and socioeconomy, and circular economy development strategies optimizing diversified industrial structures. In addition, forming eco-industrial system and changing traditional growth pattern, strategy of resource and industrial substitution and supplement, scientific and technological innovation strategy —late-comer's advantages of development of new high-tech ecocity development strategy and innovation of institutional mechanism and systems.     

灾害保险在灾害防御中的作用：以江苏省自然灾害为例

本文以江苏省的自然灾害为例,阐述了灾害保险在减轻自然灾害损失中的作用,提出在经济发达地区,灾害保险应作为灾害防御对策中的重要方面。     

科技是促进人口、资源与环境良性循环的关键因素

本文从社会系统工程角度对人口、资源与环境三者的动态依存关系作了全面探讨。认为科技是转变这个系统运动性质的关键因素,人口问题的实质是自身的消耗接近于自身的供给,解决中国人口问题的根本途径是增加科技的投入。科技类似催化剂,可使潜在资源转化为现实资源,因而人均资源占有量不会绝对呈下降曲线。科技这一要素的大量介入,将使封闭的人口、资源与环境系统(就经济学意义而言)转变为一个全方位开放的、充满活力的耗散结构系统。     

Escape take-off strategies in birds: the significance of protective cover

Avian escape strategy is highly dependent on the ability to fly, and the success rate of raptor attacks is reduced if the prey gets fully airborne. Therefore, when escaping from predator attacks, the initial take-off is crucial and a rapid take-off, high velocity, and high angle of ascent maximize the chance of survival. However, due to the laws of gravity, birds face a trade-off between maximizing its linear acceleration and maximizing its rate of climb when taking off. The optimal policy between velocity and angle of ascent when a bird escapes from an attacking predator might depend on the detailed nature of the predator’s attack, the proximity to cover, and the presence of conspecifics. Many small birds rely on a quick dash to protective cover. In this study, we examine how the availability of protective cover affects take-off strategy in birds. Male great tits (Parus major) were subjected to a surprise attack by a model predator either in the presence or absence of protective cover. When attacked by the predator, great tits took off and perched in the cover when it was available. Birds subjected to the predator attack in the absence of cover took off in 10° higher angle of ascent and flew faster in the start of the take-off, compared to birds that took off in the presence of cover. Thus, this study for the first time shows that a bird do trade off speed with angle of ascent in an adaptive way, depending on the presence of protective cover.     

国外人口与环境关系研究的理论与方法综述

人口与环境关系的研究和论争已经持续了200多年。近年来这个问题进一步引起重视。但是，由于这个领域研究的多方面复杂性。因此。在人口与环境关系研究中，不仅存在各种思想流派之间的巨大分歧，也存在研究内窖上和方法上的不同。本研究在大量阅读国外相关文献的基础上，对国外人口与环境研究的思想理论、研究方法、研究的热点问题等方面进行圊顾和评述，从而为有关方面提供一个国际社会对人口与环境领域研究的基本线索。