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1.
河流生境是维持河流生态完整性, 维护河流健康的一个重要因素, 为更科学准确的对河流生境质量进行评价,以辽宁省清河为研究区域, 分别采用熵权法和主成分分析赋权法确定权重, 构建河流生境质量评价指数(RHI), 以选择一种合理赋权方法。结果显示, 熵权法河流生境质量评价结果显示清河流域生境质量较好的河段3 个, 生境质量一般的河段6 个, 没有生境质量为好和差的河段。主成分分析赋权法评价结果显示生境质量为好的河段2 个, 生境质量较好的河段1 个, 生境质量一般的河段2 个, 生境质量为差的河段4 个。比照清河生境实际情况, 主成分分析赋权法与实际情况相贴切并对指标进行优选, 避免各指标重复赋权, 更全面准确地反映生境质量的高低。 相似文献
2.
Krzysztof Szoszkiewicz Andrea Buffagni John Davy-Bowker Jacek Lesny Bogdan H. Chojnicki Janina Zbierska Ryszard Staniszewski Tomasz Zgola 《Hydrobiologia》2006,566(1):267-280
River Habitat Survey (RHS) data collected for the EU-funded STAR project was used to identify hydromorphological characteristic
features of rivers in four European regions namely: lowlands; mountain; the Alps; and the Mediterranean. Using RHS attributes,
Habitat Quality Assessment (HQA) – a measure of natural habitat diversity, and Habitat Modification Score (HMS) – a measure
of anthropogenic modification, we identified considerable differences in frequency, diversity and evenness of features between
the regions. A relatively small subset of features clearly distinguish the hydromorphological characters of lowland, Alpine
and southern European rivers. It was more difficult to distinguish mountain rivers from Alpine rivers. The highest statistical
differences are observed between Lowland and Mountain region. Within the four regions studied the RHS attributes that most
strongly influence the HQA and HMS indices were identified. We conclude that specific effort should be made to ensure these
are recorded properly as part of the quality control of RHS data.
Electronic supplementary material Electronic supplementary material is available for this article at
and accessible for authorised users. 相似文献
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Freshwater ecosystems are declining faster than their terrestrial and marine counterparts because of physical pressures on habitats. European legislation requires member states to achieve ecological targets through the effective management of freshwater habitats. Maps of habitats across river networks would help diagnose environmental problems and plan for the delivery of improvement work. Existing habitat mapping methods are generally time consuming, require experts and are expensive to implement. Surveys based on sampling are cheaper but provide patchy representations of habitat distribution. In this study, we present a method for mapping habitat indices across networks using semi-quantitative data and a geostatistical technique called regression kriging. The method consists of the derivation of habitat indices using multivariate statistical techniques that are regressed on map-based covariates such as altitude, slope and geology. Regression kriging combines the Generalised Least Squares (GLS) regression technique with a spatial analysis of model residuals. Predictions from the GLS model are ‘corrected’ using weighted averages of model residuals following an analysis of spatial correlation. The method was applied to channel substrate data from the River Habitat Survey in Great Britain. A Channel Substrate Index (CSI) was derived using Correspondence Analysis and predicted using regression kriging. The model explained 74% of the main sample variability and 64% in a test sample. The model was applied to the English and Welsh river network and a map of CSI was produced. The proposed approach demonstrates how existing national monitoring data and geostatistical techniques can be used to produce continuous maps of habitat indices at the national scale. 相似文献
6.
The marsh fritillary is widely distributed in Wales, with over 200 populations identified in the past 15 years. However, agricultural
improvement, habitat fragmentation and changes in agricultural practices continue to impact on status and a decline in range
of 23.5% was recorded over a 10-year period. Solutions must be applied at the landscape scale to improve metapopulation viability
and, since 2000, surveys of habitat extent and quality have been carried out on 116,373 ha of grassland surrounding 111 populations.
Analysis of the results for standard ‘core landscapes’ (based on circles of 1 km radius around known populations) shows that
overall cover of suitable breeding habitat is 3.44%. However, only 11.85% of the grassland that was suitable for marsh fritillaries
was classified as being in Good Condition. The remainder was regarded as having sub-optimal vegetation structure and/or the
foodplant was at low density; 33% of the habitat resource that was not in Good Condition was regarded as inappropriately or
excessively managed and 67% was suffering from neglect. An Index of Landscape Quality is used to rank landscapes for evaluation.
Thirty-five ‘core landscapes’ (incorporating 98 marsh fritillary populations) were assessed and just four exceeded a threshold
value deemed to represent viable landscape configurations. The results have demonstrated that most marsh fritillary populations
in Wales exist within depauperate patch networks that lack sufficient breeding habitat of the right quality for long-term
persistence. Without targeted conservation action the marsh fritillary will continue to decline in Wales. This paper reports
on efforts to collect information on the quality of breeding habitat for marsh fritillaries across Wales in order to identify
priorities for conservation action. 相似文献
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长江流域鱼类资源十分丰富,产量约占全国淡水渔业产量的 60%,历史上最高产量达 4217万t[1],是我国淡水鱼最主要的集中产区。多年来,由于水工建设、 环境污染、 酷鱼滥捕等诸多原因,长江渔业资源受到严重冲击[2]。为了摸清长江渔业资源状况,20世纪70年代,农业部组织沿江六省一市协作,进行了长江水系渔业资源调查,对长江主要经济鱼类种群生物学特性、 产卵场等进行了调查研究[3]。20世纪80年代中期,农业部和中国科学院分别对长江渔业进行了调查[4],但近十余年来,未曾对长江渔业资源进行系统调查,作者根据 2001-2003 年的监测结果,对长江中游渔业资源现状进行了研究,以期为科学管理长江渔业资源提供依据。 相似文献
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In rivers, the ecological effects of drought typically result in gradual adjustments of invertebrate community structure and functioning, punctuated by sudden changes as key habitats, such as wetted channel margins, become dewatered and dry. This paper outlines the development and application of a new index (Drought Effect of Habitat Loss on Invertebrates – DEHLI) to quantify the effects of drought on instream macroinvertebrate communities by assigning weights to taxa on the basis of their likely association with key stages of channel drying. Two case studies are presented, in which the DEHLI index illustrates the ecological development of drought conditions and subsequent recovery. These examples demonstrate persistent drought effects months or several years after river flows recovered. Results derived using DEHLI are compared with an established macroinvertebrate flow velocity-reactive index (Lotic-invertebrate Index for Flow Evaluation – LIFE score) and demonstrates its greater sensitivity to drought conditions. Data from a number of rivers in south east England were used to calibrate a statistical model, which was then used to examine the response of DEHLI and LIFE to a hypothetical multi-year drought. This demonstrated a difference in response between sampling seasons, with the spring model indicating a lagged response due to delayed recolonisation and the autumn model differentiating habitat loss and flow velocity-driven responses. The application of DEHLI and the principles which underlie it allow the effects of drought on instream habitats and invertebrates associated with short or long term weather patterns to be monitored, whilst also allowing the identification of specific locations where intervention via river restoration, or revision of existing abstraction licensing, may be required to increase resilience to the effect of anthropogenic activities exacerbated by climate change. 相似文献
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Patrick J. Braaten Caroline M. Elliott Jason C. Rhoten David B. Fuller Brandon J. McElroy 《Restoration Ecology》2015,23(2):186-195
Fragmentation of the Yellowstone River is hypothesized to preclude recruitment of endangered Scaphirhynchus albus (pallid sturgeon) by impeding upstream spawning migrations and access to upstream spawning areas, thereby limiting the length of free‐flowing river required for survival of early life stages. Building on this hypothesis, the reach of the Yellowstone River affected by Intake Diversion Dam (IDD) is targeted for modification. Structures including a rock ramp and by‐pass channel have been proposed as restoration alternatives to facilitate passage. Limited information on migrations and swimming capabilities of pallid sturgeon is available to guide engineering design specifications for the proposed structures. Migration behavior, pathways (channel routes used during migrations), and swimming capabilities of free‐ranging wild adult pallid sturgeon were examined using radiotelemetry, and complemented with hydraulic data obtained along the migration pathways. Migrations of 12–26% of the telemetered pallid sturgeon population persisted to IDD, but upstream passage over the dam was not detected. Observed migration pathways occurred primarily through main channel habitats; however, migrations through side channels up to 3.9 km in length were documented. The majority of pallid sturgeon used depths of 2.2–3.4 m and mean water velocities of 0.89–1.83 m/s while migrating. Results provide inferences on depths, velocities, and habitat heterogeneity of reaches successfully negotiated by pallid sturgeon that may be used to guide designs for structures facilitating passage at IDD. Passage will provide connectivity to potential upstream spawning areas on the Yellowstone River, thereby increasing the likelihood of recruitment for this endangered species. 相似文献
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2005 年3 ～11月采用样线法和样方法对大相岭北坡大熊猫栖息地进行了调查,通过利用样方法发现的大熊猫痕迹频次对栖息地的适宜性进行景观连接度(适宜性)赋值,对大相岭北坡大熊猫栖息地的质量进行了分析评价。研究区面积约为2266.79 km2 ,其中竹林分布面积约为842.3 km2 。仅有约56.8 km2 占6.8%的竹林面积是适宜大熊猫生存的地区,次适宜地区面积为96.3 km2 ,约占11.4%,较差适宜地区面积为177.4 km2,约占21.1%,3 个等级加到一起共为330.5 km2 ,占竹林面积的39.3%,主要分布在2200～2800 m 的平缓山坡,有60% 以上为不适宜地区。人为活动对大熊猫栖息地的影响主要是不仅减少了大熊猫的生境面积,也降低了大熊猫亚种群之间的景观连接度,对大熊猫种群之间的基因交流产生阻碍。作者通过实际调查提出了管理措施。 相似文献
11.
Ellen E. Biesack Binh T. Dang Amanda S. Ackiss Christopher E. Bird Phen Chheng Latsamy Phounvisouk Oanh T. Truong Kent E. Carpenter 《Journal of fish biology》2020,97(3):696-707
Impacts of urban development on aquatic populations are often complex and difficult to ascertain, but population genetic analysis has allowed researchers to monitor and estimate gene flow in the context of existing and future hydroelectric projects. The Lower Mekong Basin is undergoing rapid hydroelectric development with around 50 completed and under-construction dams and 95 planned dams. The authors investigated the baseline genetic diversity of two exploited migratory fishes, the mud carp Henicorhynchus lobatus (five locations), and the rat-faced pangasiid catfish, Helicophagus leptorhynchus (two locations), in the Lower Mekong Basin using the genomic double digest restriction site-associated DNA (ddRAD) sequencing method. In both species, fish sampled upstream of Khone Falls were differentiated from those collected at other sites, and Ne estimates at the site above the falls were lower than those at other sites. This was the first study to utilize thousands of RAD-generated single nucleotide polymorphisms to indicate that the Mekong's Khone Falls are a potential barrier to gene flow for these two moderately migratory species. The recent completion of the Don Sahong dam across one of the only channels for migratory fishes through Khone Falls may further exacerbate signatures of isolation and continue to disrupt the migration patterns of regionally vital food fishes. In addition, H. lobatus populations downstream of Khone Falls, including the 3S Basin and Tonle Sap system, displayed robust connectivity. Potential obstruction of migration pathways between these river systems resulting from future dam construction may limit dispersal, which has led to elevated inbreeding rates and even local extirpation in other fragmented riverine species. 相似文献