海河流域滦河水系夏季大型底栖无脊椎动物多样性调查

为了解海河流域滦河水系的生态完整性和底栖动物群落的恢复,2013年5—8月对滦河水系大型底栖无脊椎动物的群落结构特征进行了初步调查,共检测到大型底栖无脊椎动物90种,隶属于7纲11目65属。利用Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数、Simpson多样性指数对滦河水系的水质进行了初步评价,在主成分分析和因子分析的基础上,对23个定量采样点的类型做了聚类分析。结果显示,水生昆虫23种,占26%;甲壳类2种,占2%;环节动物9种,占10%;软体动物10种,占11%;摇蚊幼虫46种,占51%。生物多样性指数表明滦河水系的整体水质为轻度污染,底栖动物的多样性与底质类型关系密切。     

海河流域黑龙港运东水系大型底栖无脊椎动物多样性研究

为揭示黑龙港运东水系大型底栖无脊椎动物群落结构与时空分布模式,2013年6月对海河流域黑龙港运东水系大型底栖无脊椎动物进行了采样调查,采用Margalef丰富度指数、Shannon-Wiener物种多样性指数和Pielou均匀度指数分析该水系大型底栖无脊椎动物的生物多样性,并对其进行聚类和因子分析。共检测到大型底栖无脊椎动物64种,隶属3门6纲21科49属,其中昆虫纲34种(53.1%),腹足纲13种(20.3%),寡毛纲9种(14.1%),瓣鳃纲4种(6.2%),甲壳纲3种(4.7%),蛭纲1种(1.6%)。结果表明该水系大型底栖无脊椎动物种类组成以昆虫纲的摇蚊为主,而生物量组成则以腹足纲的种类为主。该水系大型底栖无脊椎动物群落结构相对简单,物种多样性较低,生物量和密度分布不均匀,但漳卫新河和南运河段物种较为丰富。使用耐污种寡毛纲颤蚓科来指示水体污染程度,该水系各河流中游污染较轻,上游和下游河段均呈中度或重度污染。     

Small dams need consideration in riverscape conservation assessments

1. Small, off‐channel dams are generally ignored in impact assessments owing to limited information and spatial resolution issues. Previous research on South African rivers showed correlative links between high density of small dams and associated reductions in low flows, poorer water quality, and impoverished aquatic macroinvertebrate communities that were dominated by opportunistic taxa instead of specialist groups.
2. Since small dams are usually associated with catchment transformation (for example, vineyards, stock farming and exotic timber plantations), they are convenient surrogates of the impacts of catchment transformation on river functionality. Here, an index of cumulative small dams for South Africa, Lesotho and Swaziland is presented and evaluated.
3. Fifty‐two per cent of the water management catchments in the study region exceeded the threshold for the cumulative small dams density (SDD) index above which river functionality is compromised. This estimate of potentially affected catchments is considered to be conservative for reasons discussed.
4. The index results are compared with a recent systematic biodiversity planning exercise for setting biodiversity targets for freshwater areas of South Africa. Although the systematic planning included in‐stream small dams within 50 m of a river, analysis showed that 36% of all quaternaries that have high SDD score overlap with river reaches classified as ‘natural’ or ‘largely natural’.
5. Disregarding dams outside the 50 m buffer area equates to ignoring the majority of small dams (94%) in South Africa, and it is recommended that aquatic conservation assessments include the SDD index as a cost layer for prioritizing rivers for rehabilitation and conservation.

     

硇洲岛春季底栖海藻资源

2003—2005年的3—5月，对硇洲岛有代表性的大浪、谭井、存亮潮间带进行底栖海藻资源调查。分析了各地区春季不同月份藻类的种群结构和平均生物量变化，总结了各藻的生态分布区域。共得定性标本56属87种，其中蓝藻类3属4种，绿藻类14属27种，红藻类32属44种，褐藻类7属12种。其中谭井的种类最多，其次是大浪，存亮的最少。各地均以红藻为主，其次是绿藻、褐藻，蓝藻最少。种类的数量和分布具有月份上的差异。各地的平均生物量3月份以谭井的最多，4月份大浪的最多，5月份存亮的最多。潮间带海藻的生态分布区以中、低潮带为主。     

硇洲岛春季底栖海藻资源

2003—2005年的3—5月，对硇洲岛有代表性的大浪、谭井、存亮潮间带进行底栖海藻资源调查。分析了各地区春季不同月份藻类的种群结构和平均生物量变化，总结了各藻的生态分布区域。共得定性标本56属87种，其中蓝藻类3属4种，绿藻类14属27种，红藻类32属44种，褐藻类7属12种。其中谭井的种类最多，其次是大浪，存亮的最少。各地均以红藻为主，其次是绿藻、褐藻，蓝藻最少。种类的数量和分布具有月份上的差异。各地的平均生物量3月份以谭井的最多，4月份大浪的最多，5月份存亮的最多。潮间带海藻的生态分布区以中、低潮带为主。     

淦河流域底栖藻类生长特征研究

为更全面地了解淦河流域生态系统的健康状况,于2012年初春测定了淦河干流及其主要支流的水体理化指标、底栖藻类叶绿素a(Chl a)含量和无灰干重(AFDM),同时测定了部分样点底栖藻垫的磷含量及形态组成。结果显示:淦河上游各支流及干流水体的总磷(TP)、总氮(TN)和化学需氧量(COD)分别为0.014~0.072、0.282~1.204、0.77~13.26 mg·L-1,水质较好;流经市区的干流下游河段水体受到一定程度的污染,TP、TN和COD分别为0.214~0.252、2.039~2.748、9.09~16.48 mg·L-1;就总氮、总磷的含量来看,样点S1到S15的水质为Ⅱ类水,S16~S20超过Ⅴ类。各支流底栖藻类Chl a的含量在6.6~16.1μg·cm-2之间,而淦河干流样点为13.5~47.3μg·cm-2,所有样点底栖藻类的AFDM(645~3050μg·cm-2)和Chl a显著相关。底栖藻类对磷的滞留能力在一定范围内随水体营养浓度的增加而增强,下游底栖藻垫的总磷含量比上游高,最高可达82μg·cm-2;底栖藻垫中的磷形态组成以铁结合态磷(Fe-P)为主,占总磷的34%~73%,说明Fe-P对底栖藻类-水界面的磷循环起着主要的作用。研究结果对提高水体监测的认识,加强淦河流域管理和完善淦河生态系统健康状况评价具有一定的参考价值。     

Conservation of natural wilderness values in the Port Davey marine and estuarine protected area,south‐western Tasmania

• 1. Port Davey and associated Bathurst Harbour in south‐western Tasmania represent one of the world's most anomalous estuarine systems owing to an unusual combination of environmental factors. These include: (i) large uninhabited catchment protected as a National Park; (ii) ria geomorphology but with fjord characteristics that include a shallow entrance and deep 12‐km long channel connecting an almost land‐locked harbour to the sea; (iii) high rainfall and riverine input that generate strongly‐stratified estuarine conditions, with a low‐salinity surface layer and marine bottom water; (iv) a deeply tannin‐stained surface layer that blocks light penetration to depth; (v) very low levels of nutrients and low aquatic productivity; (vi) weak tidal influences; (vii) marine bottom water with stable temperature throughout the year; (viii) numerous endemic species; (ix) strongly depth‐stratified benthic assemblages exhibiting high compositional variability over small spatial scales; (x) deepsea species present at anomalously shallow depths; (xi) no conspicuous introduced taxa; (xii) a predominance of fragile sessile invertebrates, including slow‐growing fenestrate bryozoans; and (xiii) sponge spicule‐ and bryozoan‐based sediments that are more characteristic of deep sea and polar environments than those inshore.
• 2. Although this region has historically been protected by its isolation, seven major anthropogenic stressors now threaten its natural integrity: boating, fishing, dive tourism, nutrient enrichment, introduced species, onshore development, and global climate change. These threats are not randomly distributed but disproportionately affect particular habitat types.
• 3. For management of environmental risk, the Port Davey–Bathurst Harbour region is subdivided into six biophysical zones, each with different ecological characteristics, values, and types and levels of potential threat. In response to the various threats, the Tasmanian Government has enacted an adaptive management regime that includes a multi‐zoned marine protected area and the largest ‘no‐take’ estuarine protected area in Australia. Copyright © 2009 John Wiley & Sons, Ltd.

     

Plant‐associated invertebrates and ecological quality in some Mediterranean shallow lakes: implications for the application of the EC Water Framework Directive

• 1. The EC Water Framework Directive requires that Member States assess the ecological quality of their water bodies on the basis of a wide set of variables, including benthic invertebrates.
• 2. The aim of the study was to find one or more faunistic indices that could be related to ecological status of shallow lakes, independent of different macrophyte types.
• 3. Six invertebrate indices were calculated from abundance and biomass data in 10 Spanish shallow lakes: total abundance and biomass, Shannon's index, percentage of predators, percentage of Ephemeroptera, Plecoptera and Trichoptera, Orthocladiinae as a percentage of the total Chironomidae, and Chironominae as a percentage of the whole macroinvertebrate community. Taxon richness was also calculated.
• 4. Differences in the values of indices across different macrophyte types were explored by means of a one‐way analysis of variance. Significant differences were occasionally found when indices were calculated from biomass data. Total abundance was also significantly different across some architecture types.
• 5. No significant correlations were found between the overall values of the indices for each lake and the environmental variables measured (ecological status, total nitrogen, total phosphorus, chlorophyll a concentrations, dynamics of the water flow, and naturalness of the shore), except in the case of total biomass.
• 6. Values of indices were plotted (box plots) to detect potential differences between lakes of different ecological status. None of the index values was clearly related to ecological status. Thus, the approach used here, requiring relatively little sampling effort and taxonomic expertise, was of little use as a quality indicator for shallow lakes. The implementation of the Directive will therefore require different approaches to be developed and tested.

Copyright © 2004 John Wiley & Sons, Ltd.     

From a research study to a conservation partnership: Developing approaches to restoring common scoter populations

• 1. Like many sea‐duck populations, the British breeding population of common scoters Melanitta nigra has declined markedly. In 2009, a study was established to measure factors affecting lake use by breeding scoters, to inform conservation measures. That study, published in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) in 2016, showed that lakes used by scoters had relatively more shallow water and large invertebrates. Furthermore, lakes with abundant large invertebrates had relatively few brown trout Salmo trutta. These results probably reflect the importance of foraging habitat (shallow water), prey abundance (large invertebrates), and competition for prey (trout abundance) in influencing scoter lake use.
• 2. To develop this study, additional research, and scoter conservation measures, we formed a long‐term partnership, comprising nature conservation non‐governmental organizations, statutory agencies, fisheries managers and the regional hydropower company. The partnership meets regularly to coordinate and review research and develop conservation measures, building on the earlier lake‐use study.
• 3. At key scoter lakes managed for hydropower, the partnership negotiated a revised water level management regime, favouring shallow water availability in the breeding season. This regime was informed by additional research, showing the value of certain islands for nesting scoters, and water level requirements to maintain these as islands.
• 4. In a different key scoter area — an extensive near‐natural peatland where recreational angling takes place — the partnership established a trial of increased brown trout angling, with increased fish removal, to determine whether this would increase invertebrate prey abundance and benefit breeding scoters. Both conservation interventions are currently being evaluated by detailed monitoring.
• 5. Overall, the earlier study published in AQC, was important in strengthening and informing our researcher–practitioner partnership, as we collaborated within an adaptive management framework to reverse scoter declines. Long‐term interdisciplinary partnerships are likely to have an important role to play in general, for the successful conservation of aquatic biodiversity.

     

Restoration effort,habitat mosaics,and macroinvertebrates — does channel form determine community composition?

• 1. In certain lower mountainous regions of Germany multiple‐channel streams constitute the reference condition for stream restoration and conservation efforts. An increasing number of restoration projects re‐establish such stream sections, but their impact on macroinvertebrate communities remains vague and needs further elaboration.
• 2. Seven pairs of single‐ and multiple‐channel sections of mountain rivers were compared in terms of hydromorphology and macroinvertebrate communities. The stream sections were characterized by 16 hydromorphological metrics at various scales, e.g. shore length, channel feature or substrate diversity, flow variability and substrate coverage. Macroinvertebrate data were obtained from 140 substrate‐specific samples, which were combined to form representative communities for each section. Community data were subject to similarity and cluster analyses. Thirty‐five metrics were calculated with the taxa lists, including number of taxa, abundance, feeding type, habitat and current preferences.
• 3. Bray–Curtis similarity was very high (69–77%) between communities of single‐ and multiple‐channel sections. Biological metrics were correlated with hydromorphological parameters. Mean Spearman rank r was 0.59 (absolute values). The biological metrics percentage of the community preferring submerged vegetation, being grazers and scrapers or active filter feeders, percentage of epipotamal preference and the percentage of current preference (rheo‐ to limnophil and rheobiont) were significantly correlated with hydromorphological parameters.
• 4. Differences between stream sections can be attributed to single taxa occurring only in either the single‐ or multiple‐channel sections. These exclusive taxa were mainly found on organic substrates such as living parts of terrestrial plants, large wood, coarse particulate organic matter (CPOM) and mud. Reasons for high similarity of macroinvertebrate communities from single‐ or multiple‐channel sections are discussed, including the influence of large‐scale catchment pressures, length of restored sections and lack of potential re‐colonizers.

Copyright © 2008 John Wiley & Sons, Ltd.