Disturbance of natural vegetation by camping: Experimental applications of low-level stress

Previously undisturbed sites in four different vegetation types were camped on for one night and for four nights. Changes in vegetation cover and vegetation height were measured after camping and one year later. Results are presented separately for different campsite zones—parts of the site where campers slept, cooked meals, and stored their packs. Just one night of camping was sufficient to cause evident impact in all four vegetation types, although the amount of impact varied significantly between zones and between vegetation types. Vegetation impact on campsites used four nights was generally less than twice as severe as impact on the sites used one night. The effects of camping on vegetation were also predicted for 12 other vegetation types on the basis of vegetational responses to experimental trampling. These results suggest that impact can almost always be minimized by confining camping to a small number of campsites instead of dispersing use across many campsites.     

Transforming the Response in Experiments Based on Percentage Cover of Vegetation

Many ecological studies use popular variables such as percentage cover of the vegetation to assess the effects of different treatments or environmental management or conditions. Starting with sparse vegetation, the growth in percentage cover is likely to be sigmoidal, and, unless repetitive cover is measured, it will have an upper asymptote of 100%. If the initial cover values under different treatments or management regimes are not equal, then the different growth rates due to the unequal starting values will be confounded with the different treatments.A family of suitable growth curve models can be fitted to the data arising under different treatments, so that one or more of the interpretable fitted parameters of the model can be considered as "responses" to the different treatments. These responses can be analysed to compare the effects of different treatments or environmental conditions, using either parametric or non-parametric methods. The suggested approach is illustrated by application to a particular data set from the literature. The implications for the design of field studies and for the analysis of other vegetational variables are discussed.     

The consequences of backcountry surface disposal of human waste in an alpine, temperate forest and arid environment

Surface disposal of human waste by the smear method, a suggested but heretofore unexamined technique, was tested in three environments and examined for reductions in fecal mass and fecal indicator bacteria. Substantial reduction in fecal mass was observed after six and fourteen weeks of exposure in all environments, but extensive reduction in fecal indicator bacteria was observed in only the arid and alpine environments. Although surface smears appear favorable to cathole techniques in terms of indicator bacteria reduction, the application of this method is limited by several other factors common to backcountry sanitation situations. It is therefore likely that surface disposal would only be applicable in very remote, low use, alpine and arid settings where lack of soil development precludes the use of catholes and carry-out techniques are otherwise impractical.     

Review of studies on environmental impacts of recreation and tourism in Australia

The paper provides a review of available information on the impact of recreation and tourism on environments, particularly on vegetation and soil, in Australia, with an emphasis on forests. Efforts have been made to compare the current research and development situation in Australia with some overseas countries such as the United States and the United Kingdom. While many documents reveal that Australia has been experiencing an increasingly high level of recreation and tourism use in its environments, only limited studies of environmental impacts of recreation and tourism have been published. Compared with other developed countries, particularly the United Kingdom and the United States, Australia lags behind in undertaking research in this area. The results of these limited studies and some observations indicate that the most common recreational and tourist activities (such as bush walking, camping, horse-riding) can, if not well managed, adversely affect the values of Australian natural and semi-natural resources. Overall, they can affect the vegetation and other recreational sites physically and biologically. Physical effects include track formation, soil loss and/or compaction and an increase in fire frequency. Littering and water pollution are also seen as impacts associated with bush walking and camping. Biological effects include causing damage to vegetation, increasing risk of myrtle wilt disease and the spread of the soil pathogen,Phytophthora cinnamomi, as well as assisting weed dispersal. Based on the information reviewed, the authors suggest the following areas as priorities for future research into the environmental impact of recreation and tourism in Australia: determine the type of natural features that attract recreation use; determine the quantitative relationship between the impact and the level of recreation and tourism use for different activities within major vegetation habitats; ascertain site carrying capacity or environment thresholds for major vegetation habitats and recreation activities; and determine the impacts of recreation and tourism for major regions and major vegetation habitats where there have been considerable nature-based recreation and tourism activities.1998 Academic Press     

浅谈乌鲁木齐西山水源保护地植被保护与恢复

植被对水源地在防风保土、涵养水源等生态效能方面起着关键作用。但西山水源地由于地处南山风口,风灾频发,多年的过度放牧和不合理利用,使得区域内水土流失严重、荒漠草场植被盖度降低、生态与环境退化严重。为解决以上问题,需在生态防护功能优先,生态环保安全的前提下,提高生物多样性和景观异质性;充分利用种质资源,以乡土植物为主;合理利用水资源,建立免灌溉植被系统;提升生态效益、经济效益和社会效益。     

塔里木河下游应急输水植被恢复现状与问题

对塔里木河应急输水进行了介绍,比较了应急输水前后主要断面植被恢复状况,分析了应急输水后植被恢复的特征与存在的问题,提出了巩固植被恢复效果、扩大植被恢复面积及有效保护植被的措施和建议。     

古尔班通古特沙漠公路扰动带植被恢复研究

古尔班通古特沙漠区域伴随多条沙漠公路的修筑，公路沿线形成了生态扰动带（包括施工扰动带和运营扰动带）。它使地表空气流场改变、地表覆被剥离、风沙源出现、地表径流过程受阻、地表水分重分配以及生境隔离。野外考察和样品分析表明，扰动带的植被恢复取决于消面稳定性、降水的地表分配、时间、地下水位、种源和风场等因素，并初步总结出如下规律：①草方格内部表面沙层的有机质随时间逐渐增多；②草方格固沙措施加速了植被恢复的速度；③迎风坡自然覆沙，种子易于着床和萌发；④路肩上形成长营养期的中生植物，边坡形成旱生植物，路边优动带内的植被恢复情况因水分条件而变化；⑤植被恢复与时间成正比，演替过程为：短命植物、三芒草→蒿类→梭梭或白梭梭。最后提出改进草方格沙障的材料、增加土壤的有机质含量、使用干水、适时播种等恢复措施。     

山东海岸沙生植被的特点和生态评价

山东海岸分布着特殊意义的海岸沙生植被,其特点为群落类型单纯,组成种类结构简单,具有显著的镶嵌性。植物有很强的抗旱、耐瘠、耐热、耐盐能力,群落自然演替缓慢。本文对该岸区沙生植被的恢复、发展和防止生态平衡失调等问题进行了生态评价,并从植物生态学角度提出海岸开发设想。     

Analyzing the Impacts of Dams on Riparian Ecosystems: A Review of Research Strategies and Their Relevance to the Snake River Through Hells Canyon

River damming provides a dominant human impact on river environments worldwide, and while local impacts of reservoir flooding are immediate, subsequent ecological impacts downstream can be extensive. In this article, we assess seven research strategies for analyzing the impacts of dams and river flow regulation on riparian ecosystems. These include spatial comparisons of (1) upstream versus downstream reaches, (2) progressive downstream patterns, or (3) the dammed river versus an adjacent free-flowing or differently regulated river(s). Temporal comparisons consider (4) pre- versus post-dam, or (5) sequential post-dam conditions. However, spatial comparisons are complicated by the fact that dams are not randomly located, and temporal comparisons are commonly limited by sparse historic information. As a result, comparative approaches are often correlative and vulnerable to confounding factors. To complement these analyses, (6) flow or sediment modifications can be implemented to test causal associations. Finally, (7) process-based modeling represents a predictive approach incorporating hydrogeomorphic processes and their biological consequences. In a case study of Hells Canyon, the upstream versus downstream comparison is confounded by a dramatic geomorphic transition. Comparison of the multiple reaches below the dams should be useful, and the comparison of Snake River with the adjacent free-flowing Salmon River may provide the strongest spatial comparison. A pre- versus post-dam comparison would provide the most direct study approach, but pre-dam information is limited to historic reports and archival photographs. We conclude that multiple study approaches are essential to provide confident interpretations of ecological impacts downstream from dams, and propose a comprehensive study for Hells Canyon that integrates multiple research strategies.     

西气东输工程塔里木气田开发建设区生物多样性（植被）及其影响评价

西气东输塔里木气源工程的开发建设行为势必对该地脆弱生态环境下的各类生物尤其是对植被产生较大影响。过去的很多研究表明该地的植被对土地资源的保护功能是极其重要的。因此,评价油气田开发对植被的影响也是开发前期必须的工作。     

铜陵铜矿尾矿的不良特性对植被重建的影响与治理对策

铜矿尾矿库是人为造成的类似沙漠化的景观,它占用土地并带来严重的环境问题,而植被重建是恢复矿区生态系统的主要措施。本文分析了铜陵铜矿尾矿的不良特性对植被重建的影响,提出了相应的治理对策     

干旱区荒漠植被的特点及恢复问题的研究--以塔里木河流域胡杨林生态系统为例

干旱区除存在唯一的真正森林-胡杨(Populuseuphratica)林外,植被普遍极其稀疏,以降水稀少,蒸发显著为特点的干旱区,荒漠植被的存在对于生态环境的保护和良性发展起到极大的作用,干旱区的荒漠植被表现出特有的生理特征,本文研究塔里木河流域胡杨林的特征及对生态环境的适应规律,进一步提出了扩展荒漠植被的可能性及其措施。     

Vegetation changes associated with barrier-dune construction on the outer banks of North Carolina

Manmade dunes are used to stabilize the barrier islands of the mid-Atlantic coast of the United States so that they are more amenable to development. Although this strategy has stabilized extensive sections of the barrier-island substrate, it has also caused significant ecological changes. The rate and pattern of the resulting vegetation changes along the Outer Banks of North Carolina were determined using sequential aerial photography. Successional trends have been altered in favor of more stable woody communities.     

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。     

Effects of Place Identity,Place Dependence,and Experience-Use History on Perceptions of Recreation Impacts in a Natural Setting

It is generally accepted that recreation use in natural environments results in some degree of negative social and environmental impact. Environmental managers are tasked with mitigating the impact while providing beneficial recreation opportunities. Research on the factors that influence visitors' perceptions of environmental and social conditions is necessary to inform sound environmental management of protected natural areas. This study examines the effect of prior experience with the setting and two dimensions of place attachment (i.e., place identity and place dependence) on visitors' perceptions of three types of recreation impacts (i.e., depreciative behavior, environmental impacts, and recreation conflict). Principal components analysis, confirmatory factor analysis, and structural equation modeling were used to test the study hypotheses using data collected from 351 visitors through on-site questionnaires (response rate of 93 percent). The results show that prior experience exhibited a moderate and significant direct positive effect on place identity, place dependence, and visitors' perceptions of recreation impacts. Contrary to study hypotheses and prior research, neither place dependence nor place identity exhibited a significant effect on the dependent variables. The results show that prior experience causes visitors to be more sensitive to depreciative behaviors, environmental impacts, and recreation conflict. These findings raise concerns over potential visitor displacement and deterioration of site conditions. Implications for resource managers are discussed, which include education, modifying visitor use patterns, and site design strategies.     

Human Impacts to River Temperature and Their Effects on Biological Processes: A Quantitative Synthesis1

Hester, Erich T. and Martin W. Doyle, 2011. Human Impacts to River Temperature and Their Effects on Biological Processes: A Quantitative Synthesis. Journal of the American Water Resources Association (JAWRA) 47(3):571‐587. DOI: 10.1111/j.1752‐1688.2011.00525.x Abstract: Land‐use change and water resources management increasingly impact stream and river temperatures and therefore aquatic organisms. Efforts at thermal mitigation are expected to grow in future decades. Yet the biological consequences of both human thermal impacts and proposed mitigation options are poorly quantified. This study provides such context for river thermal management in two ways. First, we summarize the full spectrum of human thermal impacts to help thermal managers consider the relative magnitudes of all impacts and mitigation options. Second, we synthesize biological sensitivity to river temperature shifts using thermal performance curves, which relate organism‐level biological processes to temperature. This approach supplements the popular use of thermal thresholds by directly estimating the impact of temperature shifts on the rates of key biological processes (e.g., growth). Our results quantify a diverse array of human thermal impacts, revealing that human actions tend to increase more than decrease river temperatures. Our results also provide a practical framework in which to quantify the sensitivity of river organisms to such impacts and related mitigation options. Finally, among the data and studies we synthesized, river organisms appear to be more sensitive to temperature above than below their thermal maxima, and fish are more sensitive to temperature change than invertebrates.     

雅玛里克山植被类型及物种多样性的特征

采用典型样地法对雅玛里克山进行了植被调查，结果表明，该区的植物群落类型有14种；植物种类有223种植物．分属37科147属，植物生活型有9类；短命和类短命植物获得一定发育，旱生类型的植物占绝对优势，一年生植物占有一定比例等。     

秦皇岛市陆地植被与大气碳平衡研究

地球的碳循环已成为全球气候变化的一个热点,陆地植被是地球破循环中的一个重要贮存库。本文在分析秦皇岛市陆地植被状况的基础上,对CO_2排放量和吸收量进行了估算,结果表明,陆地植被吸收CO_2的数量占排放量的79％。结合秦皇岛市的实际,提出有利于大气碳平衡的对策。     

Phreatophytic Vegetation and Groundwater Fluctuations: A Review of Current Research and Application of Ecosystem Response Modeling with an Emphasis on Great Basin Vegetation

Although changes in depth to groundwater occur naturally, anthropogenic alterations may exacerbate these fluctuations and, thus, affect vegetation reliant on groundwater. These effects include changes in physiology, structure, and community dynamics, particularly in arid regions where groundwater can be an important water source for many plants. To properly manage ecosystems subject to changes in depth to groundwater, plant responses to both rising and falling groundwater tables must be understood. However, most research has focused exclusively on riparian ecosystems, ignoring regions where groundwater is available to a wider range of species. Here, we review responses of riparian and other species to changes in groundwater levels in arid environments. Although decreasing water tables often result in plant water stress and reduced live biomass, the converse is not necessarily true for rising water tables. Initially, rising water tables kill flooded roots because most species cannot tolerate the associated low oxygen levels. Thus, flooded plants can also experience water stress. Ultimately, individual species responses to either scenario depend on drought and flooding tolerance and the change in root system size and water uptake capacity. However, additional environmental and biological factors can play important roles in the severity of vegetation response to altered groundwater tables. Using the reviewed information, we created two conceptual models to highlight vegetation dynamics in areas with groundwater fluctuations. These models use flow charts to identify key vegetation and ecosystem properties and their responses to changes in groundwater tables to predict community responses. We then incorporated key concepts from these models into EDYS, a comprehensive ecosystem model, to highlight the potential complexity of predicting community change under different fluctuating groundwater scenarios. Such models provide a valuable tool for managing vegetation and groundwater use in areas where groundwater is important to both plants and humans, particularly in the context of climate change.     

新疆土地资源的开发利用及对环境的影响

新疆土地面积占国土面积1/6，幅员辽阔的地域决定了土地资源自然类型和可利用类型的多样性，近几十年来，新疆土地的开发仍是以农业土地开发为主，其包括开荒扩大耕地面积和广度开发和集约化生产提高单位产量的深度开发，随着西部大开发战略逐渐实施，新疆城市规模不断扩大，工业加速发展，用地需求与日俱增，本文在总结以往的土地开发利用对环境产生的利与弊基础上，为未来土地利用提出了一些趋利避害的建议。