Dynamic Evaluation on Regional Tourism Competitiveness： Urban Agglomeration of Shandong Peninsula, Eastern China

The article establishes the appraisal index system for entire urban agglomeration and its interior cities individually, concretely including five aspects： driving forces for tourism development, the level of tourism development, tourism impacts, tourism economic connection and tourism contributions of different cities to the whole urban agglomeration. As tourism competitiveness has the characteristics of comprehensiveness, systematicness and dynamicness, the article attempts to apply the structural prediction means of system dynamics to evaluating tourism competitiveness, aiming to provide some research methods and analysis ideas for tourism competitiveness measurement and trends analysis in urban agglomeration. Taking Shandong Peninsula urban agglomeration as the study area, the article simulates and analyzes the tourism competitiveness trend of the whole region and its interior cities from 2005 to 2020, and the result reflects that integrated development and regional combination of tourism are important means to upgrade tourism competitiveness in this region.     

大型水利水电工程扰动区植被的生态恢复

大型水利水电工程具有防洪、发电、航运等综合效益,是开发治理江河的骨干工程.水利水电工程建设常对项目区自然生态环境带来影响,施工中所产生的岩质边坡、土质边坡、弃土和弃渣等扰动可能导致项目区的生态系统退化、生物多样性丧失、水土流失和地质灾害加剧.扰动区植被生态恢复关系到工程安全运行和其所在区域的可持续发展.以向家坝水电工程为例,研究了大型水利水电工程扰动区植被生态恢复的目标、原则及方法.按生产、生态和社会功能,向家坝水电工程扰动区可划分为工程核心区、服务区和过渡区等3个功能区来系统规划其生态恢复.结合各自的功能需求和干扰特征,各功能区可采取相应的生态恢复技术和配置适宜物种来构建植物群落,形成结构稳定、多样性丰富、具有复合功能的植被景观.还简要评价了向家坝水电工程植被恢复现状,提出一些完善其生态恢复的建议.     

金属改性碳脱除PH3和H2S动力学及反应机理研究

为综合利用黄磷尾气中的CO,通过计算平均活化能和测定XPS、TG/DTA和氮吸附特性的方法,研究了Cu²⁺和某金属离子Mn⁺改性碳脱除PH₃和H₂S的动力学和反应机理问题。结果表明：H₂S在金属改性碳上反应时平均活化能为134.4 J/mol为-0.76级反应,PH₃在金属改性碳上反应时平均活化能为1 247.6 J/mol为-0.8级反应;减小改性碳粒径增加流量可以显著提高其脱除PH₃和H₂S的速率;XPS、TG/DTA和孔径分布分析证明,改性碳净化H₂S和PH₃是一个催化吸附过程,H₂S和PH₃首先与氧在改性碳表面进行催化氧化反应,然后生成S和P₂O₅沉积吸附在改性碳表面。     

Improving the Integration of Recreation Management with Management of Other Natural Resources by Applying Concepts of Scale from Ecology

In this article, we examine how issues of scale affect the integration of recreation management with the management of other natural resources on public lands. We present two theories used to address scale issues in ecology and explore how they can improve the two most widely applied recreation-planning frameworks. The theory of patch dynamics and hierarchy theory are applied to the recreation opportunity spectrum (ROS) and the limits of acceptable change (LAC) recreation-planning frameworks. These frameworks have been widely adopted internationally, and improving their ability to integrate with other aspects of natural resource management has significant social and conservation implications. We propose that incorporating ecologic criteria and scale concepts into these recreation-planning frameworks will improve the foundation for integrated land management by resolving issues of incongruent boundaries, mismatched scales, and multiple-scale analysis. Specifically, we argue that whereas the spatially explicit process of the ROS facilitates integrated decision making, its lack of ecologic criteria, broad extent, and large patch size decrease its usefulness for integration at finer scales. The LAC provides explicit considerations for weighing competing values, but measurement of recreation disturbances within an LAC analysis is often done at too fine a grain and at too narrow an extent for integration with other recreation and resource concerns. We suggest that planners should perform analysis at multiple scales when making management decisions that involve trade-offs among competing values. The United States Forest Service is used as an example to discuss how resource-management agencies can improve this integration.     

Linking Theory and Practice for Restoration of Step-Pool Streams

Step-pools sequences are increasingly used to restore stream channels. This increase corresponds to significant advances in theory for step-pools in recent years. The need for step-pools in stream restoration arises as urban development encroaches into steep terrain in response to population pressures, as stream channels in lower-gradient areas require stabilization due to hydrological alterations associated with land-use changes, and as step-pools are recognized for their potential to enhance stream habitats. Despite an increasingly voluminous literature and great demand for restoration using step-pool sequences, however, the link between theory and practice is limited. In this article, we present four unique cases of stream restoration using step-pools, including the evolution of the approaches, the project designs, and adjustments in the system following restoration. Baxter Creek in El Cerrito, California demonstrates an early application of artificial step-pools in which natural adjustments occurred toward geomorphic stability and ecological improvement. Restoration of East Alamo Creek in a large residential development near San Ramon, California illustrates an example of step-pools increasingly used in locations where such a channel form would not naturally occur. Construction of a step-pool channel in Karnowsky Creek within the Siuslaw National Forest, Oregon overcame constraints posed by access and the type and availability of materials; the placement of logs allowed natural scouring below steps. Dry Canyon Creek on the property of the Mountains Restoration Trust in Calabasas, California afforded a somewhat experimental approach to designing step-pools, allowing observation and learning in the future. These cases demonstrate how theories and relationships developed for step-pool sequences over the past two decades have been applied in real-world settings. The lessons from these examples enable us to develop considerations useful for deriving an appropriate course of design, approval, and construction of artificial step-pool systems. They also raise additional fundamental questions concerning appropriate strategies for restoration of step-pool streams. Outstanding challenges are highlighted as opportunities for continuing theoretical work.     

Understanding the Ecology of Blue Elderberry to Inform Landscape Restoration in Semiarid River Corridors

Societal constraints often limit full process restoration in large river systems, making local rehabilitation activities valuable for regeneration of riparian vegetation. A target of much mitigation and restoration is the federally threatened Valley elderberry longhorn beetle and its sole host plant, blue elderberry, in upper riparian floodplain environments. However, blue elderberry ecology is not well understood and restoration attempts typically have low success rates. We determined broad-scale habitat characteristics of elderberry in altered systems and examined associated plant species composition in remnant habitat. We quantified vegetation community composition in 139 remnant riparian forest patches along the Sacramento River and elderberry stem diameters along this and four adjacent rivers. The greatest proportion of plots containing elderberry was located on higher and older floodplain surfaces and in riparian woodlands dominated by black walnut. Blue elderberry saplings and shrubs with stems <5.0 cm in diameter were rare, suggesting a lack of recruitment. A complex suite of vegetation was associated with blue elderberry, including several invasive species which are potentially outcompeting seedlings for light, water, or other resources. Such lack of recruitment places increased importance on horticultural restoration for the survival of an imperiled species. These findings further indicate a need to ascertain whether intervention is necessary to maintain functional and diverse riparian woodlands, and a need to monitor vegetative species composition over time, especially in relation to flow regulation.     

Forest Dynamics in the Eastern Ghats of Tamil Nadu,India

The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation. This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between 1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning (LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data (such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of forest type and species composition among the preindependence period, the postindependence period, and the present (i.e., before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the 13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)] and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not only provide an outlook on the present status of the forests and the change trends but also provide the basis for further studies on forests in the EG of TN.     

地震的生态破坏及其恢复重建研究进展

本文从地震对生态系统的主要影响、地震破坏的生态系统恢复重建的政策及技术措施等方面,系统分析了目前国内外在地震灾害对生态系统危害方面的研究进展,以及治理中采取的政策和技术措施。在此基础上,提出了震后生态恢复重建的策略和建议,以及今后对震后生态系统快速重建和生态系统服务功能恢复中需要加强的基础研究工作。     

Renewable Resources and Economic Sustainability: A Dynamic Analysis with Heterogeneous Time Preferences

In recent years there has been increasing interest in the study of economic sustainability and its relationship with natural resources. This paper attempts to shed some light on the issue by taking into account the individual variations in time preferences for consumption and resource amenity. We characterize the long-run steady state, analyze its asymptotic stability, and explore the transational dynamics from any initial state. The welfare implications of the optimal path are also discussed.     

海莲红树林土壤CH4动态研究

对海南东寨港河港河口海莲红树林土壤CH4动态进行研究。CH4通量季节变化规律为春季>夏季>秋季>冬季,所有季节所有滩面其平均值为1.21 mg/(m2d)。不同季节CH4产生量平均值的大小顺序也为春季>夏季>秋季>冬季,所有季节所有滩面其平均值为8.28 mg/(m2d);土壤理化因子对河港海莲林土壤CH4产生率的重要性依次为全氮>NaCl>Na >Cl->SO42->含水量>总含盐量>有机质。暖季CH4氧化量高于冷季,平均值为7.06 mg/(m2d)。在所有季节所有滩面上,河港海莲林土壤CH4传输率的平均值为28.21%。