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1.
Taxonomic problems have hindered the widespread use of meiobenthos for the purpose of pollution monitoring despite its potential usefulness. The question whether it is necessary to go down to species level in order to distinguish assemblages and stations was studied using data on meiofauna densities available from a GEEP-workshop held in Norway, August 1986.
Using the complete species list of harpacticoid copepod and nematode species, the six stations could be clearly separated by different multivariate techniques (TWINSPAN, DCA, MDS, Clustering). The abundance data of the genera, the families and even the orders (in the case of nematodes) still allowed a more or less clear separation of the stations, although their relative relationships were sometimes distorted. Thus, from a practical point of view, it may be sufficient to identify the animals to genus or family level.
It is proven that this result is not due to ecological similarities between congeneric or confamiliar species. The species groups typifying the stations in the TWINSPAN analysis did not contain more confamiliar species pairs than expected from random sorting. Randomly assembled ‘families’ allowed a separation of the stations as clear as that based on taxonomic groups.
We conclude that the information contained in species abundances was preserved, at least partially, when the species are grouped, even at random. The grouping in higher taxonomic categories was as good as any, and more convenient than all the others. However, within the (limited) range of habitats studied, ecological adaptation is achieved nearly exclusively on the species level. 相似文献
2.
Fabio Bertasi Francesco Colosio Gianni Gregorio Marco Abbiati Victor Ugo Ceccherelli 《Marine pollution bulletin》2009,58(5):686-694
Sandy shores on the West coast of the North Adriatic Sea are extensively protected by different types of defence structures to prevent coastal erosion. Coastal defence schemes modify the hydrodynamic regime, the sediment structure and composition thus affecting the benthic assemblages. This study examines the effectiveness in detecting changes in soft bottom assemblages caused by coastal defence structures by using different levels of taxonomic resolution, polychaetes and/or bivalves as surrogates and different data transformations. A synoptic analyses of three datasets of subtidal benthic macrofauna used in studies aimed at assessing the impact of breakwaters along the North Adriatic coast has been done. Analyses of similarities and correlations between distance matrices were done using matrices with different levels of taxonomic resolution, and with polychaetes or bivalves data alone. Lentidium mediterraneum was the most abundant species in all datasets. Its abundance was not consistently related to the presence of defence structures. Moreover, distribution patterns of L. mediterraneum were masking the structure of the whole macrofaunal assemblages. Removal of L. mediterraneum from the datasets allowed the detection of changes in benthic assemblages due to coastal defences. Analyses on different levels of taxonomic resolution showed that the level of family maintained sufficient information to detect the impacts of coastal defence structures on benthic assemblages. Moreover, the outcomes depended on the transformation used. Patterns of distribution of bivalves, used as surrogates, showed low correlations with the patterns of the total macrofaunal species assemblages. Patterns of polychaetes, if identified to the species or genus level showed higher correlations with the whole dataset. However, the identification of polychaetes to species and genus level is as costly as the identification of all macrobenthic taxa at family level.This study provided additional evidences that taxonomic sufficiency is a useful tool in environmental monitoring, also in investigations on the impacts of coastal defence structures on subtidal macrofauna. The use of coarser taxonomic level, being time-efficient, would allow improving sampling designs of monitoring programs by increasing replication in space and time and by allowing long term monitoring studies. 相似文献
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Guanabara Bay (GB) is considered to be one of the most polluted environments of the southern Brazilian coastline. This typical estuarine system is impacted by the heavy discharge of both industrial and domestic waste from the Rio de Janeiro metropolitan area. The mollusc community structure and distribution was investigated between 2000 and 2001, using a three month sampling design of 38 stations, according to austral seasons. Species abundance was aggregated into progressively higher taxa matrices (genus, family, order) and were analysed using multivariate techniques. Mollusc distribution in GB varied significantly in space and time and was probably ruled by the organic enrichment effects of hypoxia and altered redox conditions coupled with prevailing patterns of circulation. Within the sectors of GB an increasing gradient in mollusc diversity and occurrence was observed, ranging from the azoic and impoverished stations in the inner sector to a well-structured community in terms of species composition and abundance inhabiting the outer sector. The non-metric multidimensional scaling (nMDS) and cluster analysis showed similar results when species were aggregated into genera and families, while greater difference occurred at coarser taxonomic identification (order). The literature about taxonomic sufficiency has demonstrated that faunal patterns at different taxonomic levels tend to become similar with increased pollution. In Guanabara Bay, an analysis carried out solely at family level is perfectly adequate to describe the ecophysiological stress. Further aggregation to order level changed the perceived patterns of differences. However, a different taxonomic resolution can be chosen depending on the type of ecological patterns investigated. 相似文献
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Taxonomic level for assessing oil spill effects on soft-bottom sublittoral benthic communities 总被引：6，自引：0，他引：6
Infralittoral soft-bottom macrofauna abundance data collected during four-year surveys after the Aegean Sea (Galicia, Spain) and the Amoco Cadiz oil spill (Brittany, France) at a total of seven sites were analysed at three different taxonomic levels (species, genus, and family). The effects of the spills on macrofauna populations were very similar in the two areas. The post-spill time-courses of Shannon-Weaver diversity values were similar regardless of whether species-, genus- or family-level data were used. Non-metric multidimensional scaling identified well-defined groups of samples corresponding to different times post-spill, and again the results obtained were very similar regardless of the taxonomic level considered. In general, the use of genus- or family-level data did not lead to relevant information loss by comparison with species-level data. In view of these findings and those of previous studies of this type, we conclude that family-level data is generally sufficient for monitoring pollution effects in infralittoral soft-bottom environments. 相似文献
6.
Pagola-Carte S Urkiaga-Alberdi J Bustamante M Saiz-Salinas JI 《Marine pollution bulletin》2002,44(1):63-70
In summer 1997, an intensive survey on the hard bottoms of the 'Abra de Bilbao' (N. Iberian Peninsula) was carried out in the context of the macrozoobenthic monitoring programmes developed to assess the biological recovery of the area. Three types of measurements (abundance, biomass and cover) were used to describe and compare the structure and composition of the communities at three littoral zones: subtidal, lower intertidal and upper intertidal. In addition, several taxonomic aggregation levels of data were successfully applied. The main objective of this paper is to explore the relative effect caused on the results of such programmes by earlier decisions concerning the type of measurement and the taxonomic resolution level to be applied. A 'second stage' multivariate procedure of analysis has been perforrmed based on the previously obtained sampling site ordinations. The measurement type chosen has been found to have a greater effect on the results than the taxonomic resolution used. Moreover, it is suggested that analyses based on abundance data usually lose more information when taxonomic resolution decreases than those based on biomass or cover estimates. The highest concordance among the different analyses has been found in the subtidal zone, which is considered the most appropriate habitat for the development of benthic monitoring programmes. 相似文献
7.
Ralf C.M. VerdonschotPiet F.M. Verdonschot 《Limnologica》2012,42(1):31-42
Variation in habitat structure provided by macrophytes is regarded as one of the determinants of macroinvertebrate species composition in lentic ecosystems, but mechanisms underlying this relationship appear to be confounded with site-specific factors, such as physicochemical factors, epiphyton and composition of the vegetation. To better understand the relationship between structural complexity of a macrophyte stand and its macroinvertebrate assemblage composition, it is essential to determine the ecological role of different components of habitat structure for the phytomacrofauna. Using artificial structures as macrophyte mimics, representing three growth forms (stems, broad-leaved, finely dissected) and three structure surface areas (0.1, 0.2, 0.3 m2), a full factorial field experiment was conducted in a series of drainage ditches. We investigated if macroinvertebrate assemblages colonizing the structures were affected by an increase in macrophyte structure surface area, structural complexity, or by a combination of both, and if the observed patterns were consistent among sites differing in physicochemical and habitat characteristics. Assemblages were characterized both in terms of taxonomic and functional composition, because we expected that non-taxonomic aggregation of species into functional categories would give a different insight in habitat complexity-macroinvertebrate relationships in comparison to approaches based on the taxonomic assemblage composition. Ditch intrinsic factors, in part reflected in the periphyton on the structures, explained the major proportion of the variance in both the taxonomical macroinvertebrate assemblages and functional groups among structures. Contrary to our expectation, patterns in the taxon-based and functional dataset resembled each other. Only a minor contribution of growth form to the explained variance was observed in the taxonomical dataset, whilst differences in functional composition were unrelated to habitat structure. In conclusion, processes operating on larger spatial scales overrode the micro-scale effects of habitat structural complexity and surface area on macroinvertebrates. 相似文献
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Functional diversity, e.g. based on feeding types, is frequently used for assessment procedures. By using Trichoptera genera Potamophylax and Melampophylax as examples, we demonstrate that functional diversity, based on mandible morphology, is low in the former, but high in the latter. When using functional feeding types for assessment procedures, this strictly questions identification at higher than species level and underlines the importance of providing taxonomic information by describing hitherto unknown larvae.Based on mandible morphology, the close species pair Potamophylax haidukorum and P. winneguthi, both endemics of the Dinaric Western Balkan, are omnivorous shredders, a character shared with all other known larvae of genus Potamophylax. In existing keys, P. haidukorum and P. winneguthi may be separated from morphologically close species (e.g. Allogamus spp., Micropterna spp., Potamophylax spp., Leptotaulius gracilis Schmid and Parachiona picicornis (Pictet)) by the lack of a large posterior sclerite at the lateral protuberance, by the lack of additional face setae at mid and hind femora, by the absence of numerous black spines at the pronotal surface and by the shape of metanotal sclerites. Melampophylax austriacus, an endemic of the Eastern Alps, has spoon-shaped scraper mandibles lacking teeth. This character is shared with M. mucoreus (Hagen) and M. nepos (McLachlan), whereas in M. melampus (McLachlan) teeth are present at the mandibles as it is common for omnivorous shredders. Such intra-generic functional diversity questions trait classifications on higher taxonomic units like genus or family. 相似文献
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C. Trigal C. Fernandez-Alaez M. Fernandez-Alaez 《Aquatic Sciences - Research Across Boundaries》2014,76(1):61-72
Using data from 31 ponds, we investigated the importance of environmental (e.g. habitat complexity, nutrient content, pH) and biotic factors (i.e. fish predation) on the spatial patterns of planktonic (phytoplankton and zooplankton) and benthic (macroinvertebrates) assemblages. We also evaluated the degree of concordance among assemblages and between the functional and taxonomic composition of assemblages, and test the hypothesis that surrogates of biodiversity (e.g. taxonomic or functional groups) can be used in pond conservation and biomonitoring studies. We found that the spatial patterns of benthic and pelagic assemblages were determined by macrophyte coverage, water quality and, to a lesser extent, fish. However, shifts in the taxonomic and functional composition were not congruent. Moreover, local environmental variation was slightly more important for the taxonomic than the functional composition of assemblages, except for phytoplankton. The degree of concordance among assemblages was also weak, which may be partly due to the fact that species respond individualistically to environmental variation. These findings also suggest that the coupling between benthic and pelagic habitats in flatland ponds is weak, and that the use of surrogate measures or indicator groups in pond conservation studies may not be appropriate. 相似文献
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Griselda Chaparro María Cristina Marinone Ruben J. Lombardo María Romina Schiaffino Alice de Souza Guimarães Inés O’Farrell 《Limnologica》2011,41(4):371-381
We examined the zooplankton abundance and composition of Laguna Grande, a floodplain wetland of the Lower Paraná Basin (Argentina), during an extraordinary drought–flood cycle that affected both the environment and the biological conditions of the lake. Low waters were characterised by remarkably high conductivities and pH values, and high phytoplankton and bacterioplankton abundances with cyanobacterial blooms, while high waters showed opposite features. In relation to zooplankton, the mean abundances of all the taxonomic groups (rotifers, cladocerans, copepods, ciliates, and heterotrophic nanoflagellates) were slightly higher at low waters. Major changes were observed in the specific composition of metazooplankton: the euryhaline species assemblage that dominated in the dry warm period was replaced by several oligohaline littoral and planktonic species characteristic of the Paraná River Basin, when the water level rose. Mean species richness values at high waters doubled those of low waters and were directly correlated to water depth. Most of the rotifers of the genus Brachionus and the cladoceran Moina micrura switched from parthenogenetic to sexual reproduction during low waters, as a response to a harsh environment and crowding. We suggest that the main changes in the environmental conditions in this eutrophic floodplain lake are driven by the hydrology, which regulates the zooplankton succession. The herein described shifts in the zooplankton structure and dynamics of Laguna Grande over an extraordinary drought–flood cycle contribute to the understanding of the processes that might occur under the scenarios predicted by climate change models. 相似文献
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刚毛藻(Cladophora)生态学研究进展 总被引：1，自引：0，他引：1
刚毛藻(Cladophora)在全球海洋及淡水中普遍存在,它为沿岸带微生物和无脊椎动物提供了生产力和微生存空间.随着水体富营养化程度的加剧,刚毛藻在沿岸带出现暴发现象,造成严重的环境污染,同时刚毛藻的存在也影响了湖泊生态修复过程中沉水植被的恢复.本文从刚毛藻形态与种类鉴定、生长与分布影响因素、生长周期与种群动态、种间关系及生物去除等研究前沿方面进行综述,并对相关研究领域进行展望,为进一步研究刚毛藻生态生理特征、有效控制和去除提供科学依据. 相似文献
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An illustrated dichotomous key to larvae of all genera of Plecoptera in the West Palaearctic region (i.e., Europe, Asia Minor and the Palaearctic part of northern Africa) is presented. Brief comments on included species are added for each genus, plus diagnostic details of selected bioindicator species. Two appendices provide a key to larvae of the German species of genus Nemoura and taxonomic notes on selected species and operational taxonomic units in genus Leuctra, respectively. 相似文献
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The results of multidisciplinary environmental field studies aimed to elucidate the forms of influence of the Tsimlyansk Reservoir onto coastal ecosystems are presented. The ecotone analysis of the ecosystem structure of the reservoir coast is proposed as an approach to the analysis of the collected data. A brief characteristic of a version of a geographic information system based on field and remote-sensing data is given. A relationship is shown to exist between the reservoir level regime according to 10-year data and the transformation of vegetation cover on the coast against the background of minor changes in soils for the 50-year period of reservoir existence. 相似文献
16.
抚仙湖有近210亿m3的优质淡水资源,具有重要战略价值,但是近年来出现水质退化的现象.沉水植被是湖泊生态系统功能维持的重要生物门类,其演变过程能反映和影响整个生态系统的变化,目前还缺乏对抚仙湖沉水植被长期连续地观测记录.本文基于Landsat遥感数据分析了抚仙湖北部沉水植被面积的动态变化,结合气候变化和水质水文要素分析发现：抚仙湖北部湖区沉水植物在1987—2020年间存在先减少后增加的变化趋势;1987—1995年,沉水植物分布面积约占北部湖区面积的1.64%;1996—2010年北部湖区沉水植被分布面积缩减,湖泊处于高水位低营养状态,水位上升是此时期沉水植物面积减少的主要原因;2011—2020年,水位降低,营养增加,营养和水位的共同作用导致抚仙湖北部湖区沉水植物面积显著增加.沉水植物覆盖度变化伴随着沉水植被以苦草为优势种群转为以穗花狐尾藻为优势种群,沉水植被结构转向耐污染性更强的属种.通过抚仙湖北部湖区沉水植被发育与营养、水位等驱动因子的关系分析,建议现阶段需要严格限制入湖氮磷排放,强化水生植被的长期动态监测,构建水量、水质、水生态一体化监测体系,并开展抚仙湖生态系统演变的模拟和预测,防止抚仙湖生态系统出现突变,以维持抚仙湖生态系统功能多样性. 相似文献
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水位变化对河流、湖泊湿地植被的影响 总被引：12，自引：6，他引：6
水位是湿地生态水文过程的关键因素之一,其改变将影响湿地植被覆盖度和物种组成,最终产生群落演替.从水位梯度,水位波动和人工控湖、控河工程3方面论述水位变化对湿地植被的影响:由于对水位选择的不同及彼此竞争力的差异,湿地植物种沿水位具有梯度分布现象,同时形态可塑性能对其分布范围产生一定影响;水位波动的频率和淹没持续时间对于植被演替具有基础性的作用,水位波动幅度的影响则相对较小,周期性波动能维持以草本植物为主的湿地植被的物种多样性和稳定性,非周期性波动以洪水、干旱为主,易促进湿地植被向固定的水生或陆生方向演替;人工控湖、控河的影响在机理上并无特殊之处,但保证物种多样性和生态系统稳定性的各种缓解措施具有较高的参考价值.基于机理的量化模型,自然、人为因素驱动下水位变化对湿地植被影响的差别研究,模拟水位波动实验以及人工控湖、控河工程的跟踪观测将是今后该领域研究的热点. 相似文献
18.
To investigate the combined effects of decreasing taxonomic resolution (i.e. species, family, phylum), the use of different mesh-size (1.0 mm and 0.5 mm) and the type of samplers used (van Veen vs. corers taken by divers) on the quality of data obtained, a comparative study was undertaken with the overall aim of identifying cost efficient methods for routinely monitoring the ecological change caused by Mediterranean fish farming. The results clearly showed that information loss was relatively low as data were aggregated at higher taxonomic levels, particularly up to the level of family or even order. It was also found that the extra information gained by sieving samples through a 0.5 mm sieve did not improve the ability to distinguish the potentially impacted sites from the control stations. Finally, it was found that a relatively large proportion of the available information concerning the community structure such as abundance, biomass or diversity is lost when sampling is carried out with corers. A cost/benefit ratio analysis for the two sampling and the two sieving methods showed minimal values for the van Veen samples (for both sieve fractions) at the family level, indicating that analysis at this level gives the best balance between precision of the results and decrease in taxonomic effort. However, if the time needed to sort the samples is included in the analysis, then samples taken with corers using a 0.5 mm sieve and identified to families seems like a good compromise between precision and cost. 相似文献
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Taxonomic sufficiency (TS) involves the identification of taxa only to a level of taxonomic resolution sufficient to permit the detection of changes in stressed assemblages. Recently, however, TS has been proposed also for conservation issues as a tool to estimate biodiversity over large areas and in poorly known environments. This paper briefly reviews the use of TS in environmental impact studies and the effects of TS on sampling procedures and data analyses. The risk of possible loss of information depending on TS and the studied environment are discussed. Concluding remarks deal with the dangers of loss of taxonomic expertise in marine biological studies and assess critically the proposal of TS as a tool to describe biodiversity at a taxonomic level higher than species. 相似文献