Trophic Ranking Research Articles

The Impact of Mine Effluents on the Water Quality and Macrophyte Plant Communities in the Kifubwa Stream, Solwezi, Zambia

A study to assess the impact of mine effluents on water quality and macrophyte plant communities in the Kifubwa stream in Solwezi, Zambia was carried out in December 2015. The macrophytes species and water samples were collected from ten (10) selected sampling sites along the river. The initial sampling site was set at the point of pollution (effluents) entrance into the river. The other 9 sampling units of 30 m × 30 m were spaced at a uniform interval of 150 m throughout the 1.5 km section of the river sampled. Macrophytes collected at each sampling site were identified on site to family level using the Zambian Macrophytes Trophic Ranking (ZMTR) protocol developed under the Southern African River Assessment (SAFRASS). The abundance of macrophyte plant communities showed that family Polygonaceae had (27.5%), Cyperaceae, (23.5%), Amaranthaceae (17.6%), Hydrocharitaceae (17.6%) and Osmundaceae (13.8%) respectively. The Shannon-Weiner’s diversity index (H) was used to calculate the macrophyte diversity and the value used in a correlation analysis with potential of hydrogen (pH) and other water quality variable under investigation. The water samples were taken to the laboratory for analysis of water variables, namely, pH, Total Dissolved Solids (TDS), nitrates, phosphates, copper and zinc levels for each site. The pH was significantly (p 0.05) related to H and zinc. Calculated means for pH and TDS showed that they were within both the Zambian Drinking Water Standards (ZDWS) and the World Health Organization (WHO) guidelines. Phosphates, nitrates and zinc were all below both water standards. Only copper levels were above both water standards. The mine effluent that is being discharged in the Kifubwa stream does have an impact on the water quality parameters, especially that of copper. This requires regular monitoring of the stream effluents by the authorities that give the permission for the discharge.

The Zambian Macrophyte Trophic Ranking scheme, ZMTR: A new biomonitoring protocol to assess the trophic status of tropical southern African rivers

The Zambian Macrophyte Trophic Ranking system (ZMTR) is a new bioassessment scheme to indicate the trophic status of tropical southern African river systems. It was developed using a dataset of 218 samples of macrophytes and water chemistry, collected during 2009–2012, from river sites located in five world freshwater ecoregions primarily represented in Zambia. A typology based on these ecoregions, and three stream order categories, was used to determine soluble reactive phosphate (SRP) reference conditions. Zambian Trophic Ranking Scores (ZTRSsp) were calculated for 156 species, using direct allocation from SRP data for 80 species, in samples for which sufficient available SRP data existed. An indirect quantitative procedure, based upon occurrence of species in six sample-groups, of differing mean SRP status, produced by TWINSPAN classification, allocated provisional ZTRSsp values for the remaining 76 species. Additional data for nitrate, pH, alkalinity and conductivity were used to help assess the trophic preferences of macrophyte species showing differing ZTRSsp values. ZMTRsample values were calculated as the mean ZTRSsp score of species present per sample. ZMTR indicated trophic status reasonably accurately for 83.1% of Zambian samples, and for all samples within a test dataset from Botswanan rivers. Examples of application of the methodology, and its potential for hindcasting river trophic status are provided. The scheme currently underestimates highly-enriched conditions, and, to a lesser extent, overestimates the trophic status of some very low-nutrient rivers, but at this pilot stage of development it generally predicts the trophic status of tropical southern African river systems quite well.

Responses of aquatic macrophyte assemblages to nutrient enrichment in a lowland river basin of western Greece

In Greece, as in many other Mediterranean countries, there is a lack of information enabling the use of aquatic macrophytes as biological indicators of the water trophic status. This research aimed to investigate the trophic preferences of the aquatic macrophyte assemblages encountered in selected standing water bodies of a lowland river basin of western Greece. It also aimed to assess the response of the macrophyte species that occur in the studied water bodies to different nutrient concentrations. A total of 56 macrophyte species were identified. TWINSPAN analysis distinguished four main vegetation groups potentially related to three trophic types. The Trophic Ranking Score developed in the UK was applied in order to investigate the trend in aquatic macrophytes in response to the different trophic conditions. The results indicated that TRSUK was not in accordance to the water trophic indices. After the addition of 14 new species and the re-scoring of the plants from the UK list, the re-calculation of TRS enabled a better classification of the trophic status convergent with the information from the water trophic indices. The current study constitutes a reference document providing basic information, and must be improved by updating the plant list with new data from other sites.

Classifying aquatic macrophytes as indicators of eutrophication in European lakes

Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (non-linear) response curve along a phosphorous gradient. These thresholds revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general response of well known indicator species seems to hold, there are many species that were evaluated differently according to the database selection and classification methods. This hampers a Europe-wide comparison of classified species lists as used for the status assessment within the WFD implementation process.

Using aquatic macrophyte community indices to define the ecological status of European lakes

Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) is to be partially based on the species composition of the aquatic macrophyte community. We tested three assessment methods to define the ecological status of the macrophyte community in response to a eutrophication pressure as reflected by total phosphorus concentrations in lake water. An absolute species richness, a trophic index (TI) and a lake trophic ranking (LTR) method were tested at Europe-wide, regional and national scales as well as by alkalinity category, using data from 1,147 lakes from 12 European states. Total phosphorus data were used to represent the trophic status of individual samples and were plotted against the calculated TI and LTR values. Additionally, the LTR method was tested in some individual lakes with a relatively long time series of monitoring data. The TI correlated well with total P in the Northern European lake types, whereas the relationship in the Central European lake types was less clear. The relationship between total P and light extinction is often very good in the Northern European lake types compared to the Central European lake types. This can be one of the reasons for a better agreement between the indices and eutrophication pressure in the Northern European lake types. The response of individual lakes to changes in the abiotic environment was sometimes represented incorrectly by the indices used, which is a cause of concern for the use of single indices in status assessments in practice.

Trophic ranking of the biota in Iliamna Lake, Alaska

Trophic ranking of the biota in Iliamna Lake, Alaska

A method for estimating the extent of standing fresh waters of different trophic states in Great Britain

Abstract1. The total area of standing fresh water in Great Britain has been estimated at approximately 2400 km2. The aim of the work described in this paper was to estimate the extent of the dystrophic, oligotrophic, mesotrophic and eutrophic habitat types making up this total.2. Botanical survey data collected by the statutory nature conservation agencies provided habitat type and surface area for 3500 water bodies, mostly in Scotland. Because survey in England and Wales had been less thorough than in Scotland, it was not possible to estimate the areas of habitat types simply by direct extrapolation from the survey sample to the total resource of standing water in Great Britain.3. A system of Trophic Ranking Scores (TRS) has been developed for aquatic plant species. Using plant records from the Biological Records Centre, a mean TRS for each 10×10 km square was produced, and Great Britain was divided into TRS bands. For each of these bands, the percentage by surveyed area of each freshwater habitat type was calculated. These percentages were applied to the total area of standing water in each TRS band, obtained from Ordnance Survey summary statistics, in order to predict the proportions of the different habitat types likely to occur in each band. The extent of these habitats in Great Britain as a whole could then be calculated.4. Estimates produced by this method of the extent of the four standing freshwater habitat types in Great Britain are: dystrophic — 11 km2 (0.5%); oligotrophic — 1445 km2 (60%); mesotrophic — 267 km2 (11%); eutrophic — 679 km2 (28%).5. The application of this work to nature conservation is discussed. Copyright © 2001 John Wiley & Sons, Ltd.

Macrophyte functional variables versus species assemblages as predictors of trophic status in flowing waters

A series of models was developed using functionally-derived variables (mainly based on morphological attributes of freshwater macrophytes) to predict the trophic status of river and associated channel systems. The models were compared with an existing species-assemblage based procedure for predicting British river trophic conditions (the Macrophyte Trophic Ranking scheme, MTR). We compared sites in cooler temperate conditions (in Scotland) and warmer, sub-tropical conditions (in Egypt). In total, we made measurements of 13 traits from >600 individual plant specimens of 33 species growing at 42 sites (divided into independent input and test site datasets). N status (as annual mean concentration in water of total oxidised nitrogen, TON) was only very poorly predicted by this approach. However, P (as annual mean concentration in water of soluble reactive phosphate, SRP) was better predicted: both by a model based on MTR (r = -0.585, p<0.001), and by models using functional attributes of the macrophyte vegetation. River Trophic Status Indicator (RTSI) models based on ranked plant functional group relationship to river water P concentrations (RTSI FG ), or field-measured trait sets of the plants (RTSI TR ) could also individually explain up to about 34% of the variation in P, both for the total dataset and for subsets from Egypt or Scotland alone or for high V. low-flow sites. Combining both types of RTSI measure produced the most powerful predictive model ( r = 0.72, p<0.001), explaining just over half the variability in P.

A revised classification system for British rivers based on their aquatic plant communities

1. This paper describes a classification of British rivers based on their aquatic plant communities, and represents a revision of an earlier version published in the early 1980s. 2. Data on macrophytes from 459 riverine sites were added to the original database of 1055 sites, and analysed using TWINSPAN (Two-Way Indicator Species Analysis). 3. The overall structure of the new classification is the same as the first version. The highest level consists of four broad groups (A–D) representing an environmental gradient from lowland eutrophic rivers, to those that are essentially upland, torrential and oligotrophic. These four groups are divided into 10 River Community Types (RCTs) with further sub-divisions into 38 sub-types. For many sites, their allocation to a particular RCT has remained unchanged; other sites have been reassigned and this process has helped remove some of the minor anomalies in the previous system. 4. The results have confirmed that aquatic macrophytes are a valuable tool for classifying rivers, and suggest that in the absence of natural stress or human impact most communities are sufficiently robust to remain stable over time. 5. The original system has been used extensively over the past 15 years, particularly for nature conservation assessment. New applications include trophic ranking techniques for water quality monitoring, and the integration of the botanical classification within a broader system for conservation evaluation. It is intended that in future the classification will be extended to incorporate rivers in Northern Ireland, thus creating a system applicable to the whole of the UK. © 1998 John Wiley & Sons, Ltd.

The duckweed Lemna minor compared with the alga Selenastrum capricornutum for bioassay of pond-water richness

In an initial comparison of Lemna and Selenastrum bioassay, on water from two ponds, both organisms made greater growth in the more nutrient-rich water. However, when the comparison was extended to 57 diverse ponds, the two bioassay organisms responded to different aspects of water quality. Lemna and Selenastrum growth were not correlated, and were not necessarily related to the same water-quality variables: e.g. Lemna dry weight was correlated with Ca, Mg and K while Selenastrum cell concentration was correlated with PO 4, NH 4, NO 2 and (negatively) with pH. Neither Lemna nor Selenastrum growth were related to the number of hydrophyte species or their average trophic ranking score. Thus, bioassay to assess pond richness, either using Lemna or Selenastrum, is not straightforward and is probably best used alongside water analysis and/or vegetation survey.

A botanical classification of standing waters in Britain: Applications for conservation and monitoring

Abstract1. A classification is described based on an indicator species analysis of the vegetation of 1124 fresh and brackish standing water sites in Great Britain.2. Ten Site Types are recognizable by their assemblages of plants, and these groupings are related to the alkalinity, pH and conductivity of the water. One Type consists of extremely acid water bodies on peat. There are two other nutrient‐poor Types, distinguishable from each other largely by size and substrate, as well as by vegetation. These sites lie mostly in the north and west of Britain. There are four distinct Site Types with nutrient‐rich water, one characteristic of Scotland, the rest more typical of the lowlands of southern and eastern Britain. A further Site Type is regarded as mesotrophic and is found mainly in northern England and Scotland. Of the remaining two Site Types, one shows an unusual combination of base‐poor and base‐rich characteristics and the other comprises brackish sites in Scotland.3. The use of the classification for producing Trophic Ranking Scores, both for individual species and for sites, and the application of these scores for monitoring the nutrient status of fresh waters are explained.4. The application of the classification to the selection of sites important for nature conservation is discussed, with special reference to north west Scotland.5. This classification is compared with other classifications of aquatic vegetation in Great Britain.

Diets and Trophic Ranking of Ungulates of the Northern Serengeti

Diets and Trophic Ranking of Ungulates of the Northern Serengeti

Comparisons of trophic state measurements

Twenty-nine methods commonly used to measure trophic state were compared with respect to their ability to rank 44 test lakes against two standards: total phosphorus, a nutrient or driving force standard and chlorophyll a, an eutrophication response standard. The phosphorus loading models had high rank correlations with phosphorus; however, they did not rank the lakes well against chlorophyll. The relative trophic ranking of many lakes differed depending upon whether primary nutrients or biological manifestations were used as the ranking mechanism. Secchi disk was very effective in ranking the lakes against phosphorus but was relatively ineffective in ranking them against chlorophyll. Total Kjeldahl nitrogen was effective in ranking the lakes against phosphorus and had the highest rank correlation of all the methods tested against chlorophyll. Methods based upon phytoplankton community structure were especially ineffective in ranking the test lakes. Algal assay control yield gave disappointing results when compared against the chlorophyll standard. Most methods were much more effective in ranking the lakes against the total phosphorus standard than the chlorophyll a standard.