Macroinvertebrate Survey of watercress farm outflows, Alresford , Autumn 2020
Report prepared by Robert Aquilina MSc MCIEEM
September 2020
Macroinvertebrate survey of watercress farm outflows, Alresford, Autumn 2020
Robert Aquilina MSc MCIEEM
September 2020
Robert Aquilina MSc MCIEEM is an independent consulting ecologist specialising in protected species and freshwater ecology. He is a Full member of the Institute of Ecology and Environmental Management and abides by their Code of Professional Conduct. For further details see www.cieem.net www.aquilina-environmental.co.uk
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Table of contents Summary .............................................................................................................. 4 Introduction .......................................................................................................... 5 Methods ............................................................................................................... 5 BMWP ............................................................................................................................................. 6 WHPT .............................................................................................................................................. 7 Locations ......................................................................................................................................... 7
Results ................................................................................................................. 11 Discussion ............................................................................................................ 14 References ........................................................................................................... 16 Appendix 1 Species recorded. ............................................................................... 17
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Summary
Macroinvertebrate surveys of outflows from Bishop’s Sutton, above and below Drayton Farm and Manor Farm watercress farms at Alresford, Hampshire were carried out using standard sampling techniques. The purpose was to repeat surveys undertaken in the autumn of 2019 in order to investigate any changes and identify any potential water quality issues. The species present were typical of a chalk stream, with good diversity and water quality scores. A complete list of species is presented together with abundance and diversity (WHPT) scores. Comparison is made with results from the previous year. Changes appear to be within normal variation in sampling efficacy and natural seasonal variation.
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Introduction
The purpose of this survey was to repeat the assessments carried out the previous year of the discharges from the watercress beds at Bishop’s Sutton, Drayton and Manor Farm around Alresford and identify any impacts to biodiversity. The protocols followed were identical to those used previously and as such, this report follows the format of the previous report (Aquilina, 2019). Much of the descriptive material is retained from that report in order to facilitate understanding. Drayton and Manor Farm are situated at the head of small chalk streams and use borehole water to supply the watercress beds which then is discharged into the stream. Bishop’s Sutton is located slightly further down the headwaters of another stream but is also fed by borehole water. All three unnamed streams join the River Alre either directly (Manor Farm) or via Old Alresford Pond. The River Alre in turn joins the River Itchen, an important chalk stream for salmon and trout fishing and conservation. Sampling at Drayton Farm was carried out above and below the main site as per previous sampling. The Drayton sites were visited by Robert Aquilina on Monday 7th September 2020 and Manor Farm and Bishops Sutton on Tuesday 15th September 2020. The reason for the split visits was that the weather was unusually warm and no refrigeration was available to store samples whilst waiting to be sorted as in previous years. Therefore there was concern that samples may deteriorate affecting the results. By splitting the sampling, sorting could take place on the same and following day as collection. The weather conditions were dry and suitable for the survey with normal water flow levels. Industry standard survey and extraction techniques for the stream (Environment Agency 2012) were used to assess the species present. Methods The methodology followed is the standard Environment Agency survey and extraction protocol which results in a species list with abundance data. This forms the basis for calculating a number of indices designed to assess the impacts of various factors (depending on the index selected) but in this case is used to calculate the WHPT index (Walley Hawkes Paisley Trigg - river invertebrate index that is used 5
as the basis for river invertebrate status classification for Water Framework Directive) . Aquatic macroinvertebrates were collected using a standard size FBA D-frame pond net from the major habitats along the stream (stands of different wetland plants, distinctive substrates, tree roots etc.). All the different habitats present were allocated a proportion of the overall sampling time (3 minutes) and different areas of the same mesohabitat were subsampled to ensure that as great a range as possible was sampled. Each location was also searched for an additional minute looking for surface dwelling animals such as water skaters and whirligig beetles and inspecting submerged habitats such as logs and larger stones for attached animals. The samples were preserved in 70% IMS and sorted in the laboratory, where all the invertebrates were extracted. The standard BMWP invertebrate groups were recorded : Tricladida (flatworms), Gastropoda (snails and bivalves), Crustacea (slaters, shrimps and crayfish), Hirudinea (leeches), Megaloptera (alderflies), Plecoptera (stoneflies), Ephemeroptera (mayflies), Odonata (dragonflies and damselflies), Hemiptera (water bugs), Coleoptera (water beetles), Trichoptera (caddisflies) and Diptera (true flies). Voucher specimens were retained in order to check their identity. Dead mollusc shells, and empty caddis cases were discarded and only whole animals were included in the counts.
BMWP Condition assessment of running waters is based on the BMWP (Biological Monitoring Working Party) score. These BMWP family scores (1-10) are industry standard and reflect the sensitivity of the families to pollution. The higher the family score, the more sensitive to oxygen depletion the family is and therefore their presence indicates a cleaner or less impacted site. The effects of pollution generally are to impose a Biological Oxygen Demand upon the receiving waters and so sensitive families are progressively excluded as the BOD increases. The score for each family present is totalled to give a site score. Because these site BMWP scores are influenced by sample size (a high score can be achieved through a large number of low scoring families as well as a small number of high scoring families) an Average Score Per Taxa (ASPT) is also calculated from the resulting BMWP scores and allows further interpretation of the results. The higher the ASPT, the greater the proportion of more sensitive families in the sample and therefore the better the site condition.
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WHPT WHPT better reflects the quality of the invertebrate community because it is based on a wider range of taxa (mostly families). In particular, WHPT includes more families of Diptera and some families that were grouped together in BMWP (known as BMWP composite taxa) are considered separately in WHPT. So 106 taxa are included in WHPT as opposed to the 82 in BMWP. Additionally the abundance of each taxa is taken into account through the use of abundance classes, the WHPT score for each taxa present depending on its abundance.
Abundance category Numerical abundance AB1 AB2 AB3 AB4
1-9 10 -99 100 - 999 >1000 Table 1: WHPT abundance classes
Apart from accounting for abundance, the calculation of scores is the same as for BMWP and results in equivalent but more accurate reflection of water quality. The scores derived are WHPT overall score (equivalent to BMWP), N taxa and ASPT.
Locations All locations are as sampled in previous years and are described below with any changes in the habitat noted. The Bishop’s Sutton outflow is located at SU 60400 32321. The outflow channel is canalised and subject to fast deep flow. There is a gravel bed with strong Ranunculus growth but the banks are vertical stone with little vegetation. Therefore mesohabitats were limited to gravel, Ranunculus, marginal vegetation and the Fontinalis moss growing downstream of the weir. Sampling was concentrated in the Ranunculus which dominated the site (90% cover) and so little of the gravel was sampled as compared with the previous year.
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Photo 1. Bishops Sutton.
The below Drayton outflow was located at SU 59358 33272. The sample reach was downstream of a bridge with culverts discharging the water, leading to scour in the channel bed. Substrate in this area was gravel with cobbles but was of limited extent. Further downstream, the substrate was fine and soft underfoot in the majority of the channel with some gravel reaches. Banks were earth but had little marginal vegetation. No in-channel vegetation was present presumably because of the shade from the trees. Sampling was concentrated in the gravel and cobble area for 2 minutes and then upstream of the bridge for 1 minute in gravel.
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Photo 2. Below Drayton Farm The above Drayton outflow was located at SU 59682 33310. The channel is approximately 1 - 1.5 metres wide and 0.2 – 0.3 metres deep. Water flow is maintained by discharge from the borehole. The habitats present consisted of gravel, coarse and fine sands, Ranunculus beds and marginal Glyceria maxima with small amounts of other marginal plants. This represents the head of the stream as upstream are the watercress beds and borehole supply. A good balance between Ranunculus growth and gravel (50:50%) was present this year compared to the previous which had been dominated by Ranunculus.
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Photo 3. Above Drayton Farm.
The Manor Farm outflow is located at SU 58532 33516. The habitats present consisted of cobbles, small stone, gravel, coarse sand, with significant regrowth of marginal vegetation (Watercress and Water Speedwell) after the vegetation clearance to improve flow last year. There was only limited recovery of in-channel Ranunculus. The tree that had fallen across the stream close to the discharge point had been removed and significant disturbance to the far side of the river had occurred. The riverbed appeared to have been scraped and dumped onto the far bank. Although this did not impact the sampling site, some effects through sediment uplift may have occurred.
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Photo 4. Manor Farm.
Results
The full species lists are presented as an appendix. The results summarised here consist of number of species, abundance and WHPT, N-taxa and ASPT for 2019 and 2020. The significant measure of water quality is the ASPT score. This is because gross scores such as abundance or WHPT are heavily influenced by sampling bias and would be expected to vary on every occasion to some extent. To overcome such bias the Average Score Per Taxon (ASPT) is calculated which reflects more accurately the water quality with higher scores representing less impact.
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Site
Date
Season
# species
Bishop’s Sutton
3/9/19
Autumn
54
2488
38
201.9
5.31
15/9/20 Autumn
46
3035
32
161.8
5.06
Autumn
41
918
31
160.8
5.19
Autumn
40
1043
34
175.0
5.15
Above 22/8/18 Summer Drayton Farm 3/9/19 Autumn 7/9/20 Autumn
46
1966
32
149.4
4.67
45 43
1242 1772
33 35
165.4 160.8
5.01 4.59
Manor Farm
53 47
2699 4894
38 35
211.6 174.0
5.57 4.97
Below 3/9/19 Drayton Farm 7/9/20
3/9/19 Autumn 15/9/20 Autumn
Abundance Ntaxa
WHPT ASPT
Values showing an increase are highlighted in blue Table 2. Results summary The results show an increase in 7 out of the 16 values. Abundance at all sites was up but the other parameters were mostly comparable. A seasonal mean is the best manner of assessing differences and this is shown below, albeit based only on two data points so far. Site
Mean N-taxa Mean WHPT Mean ASPT
Bishop’s Sutton Below Drayton Above Drayton Manor Farm
35 32.5 34 36.5
181.85 167.9 163.1 192.8
5.185 5.17 4.80 5.27
Table 3. Seasonal means (autumn)
Differences appear to be within the normal variation in sampling efficiency and natural seasonal fluctuation. Much of the variation in species richness is contributed by single occurrences of species whereas most of the variation in abundance is due to variation of a small number of species. Gammarus counts are summarised below and show an increase at all sites from the previous year. 12
Site
Sept 2019 Sept 2020
Bishop’s Sutton Below Drayton Above Drayton Manor Farm
928 364 159 1341
1606 440 580 3598
Table 4. Gammarus counts
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Discussion It is still early to expect any trends to show up as there are have only been two years consistent sampling undertaken so far and strictly speaking only the same seasons data is comparable. The results suggest an increase in WHPT scores from the first sample occasion (May 2019 or August 2018 for Above Drayton Farm), but with a decline from the intervening samples. This illustrates the natural variation between seasons and years, rather than any significant decline in water quality. The variation in scores is accounted for by relatively insignificant changes in animals captured. For example 76% of the difference in the scores for Manor Farm, the site which shows the greatest fall between 2019 and 2020, is accounted for by just 4 individual animals (2 dance flies and one each of two caddis species).
WHPT scores 220 210 200 190 180 170 160 150 140 130 120
Manor Farm
Above Drayton
Below Drayton
Bishops Sutton
A change in the relative cover of one of the habitats present can account for the shift to lower scoring families which reduces the WHPT and ASPT scores. For example the increase in the marginal vegetation at Manor Farm allows many less oxygen sensitive species to be included as well as reducing the percentage of the most sensitive species from the gravel. Gammarus counts have all increased from September 2019 to September 2020, which may be due to the warmer weather of 2020. Indeed the warmer weather will cause an increase in water temperatures which lead to a decrease in dissolved oxygen. Neither of these parameters are monitored in these surveys, so this can only be inferred. However, the effects would be to lower the occurrence of the more sensitive, higher scoring families which is seen in these results. 14
Overall it is concluded that two factors are the major influence on these results: Normal variation in sampling efficiency which has been suggested as representing 9 – 12 % between experienced practitioners (Clarke et al., 2002). Natural year on year variation in abundance and species presence. Weather patterns and weed growth (and management) are likely to be major influences. It is expected that there would be at the very least 10% variation between years. Together an annual variation of 20-25% seems a reasonable expectation and these results fall well within this. One curious record is that for a beetle Dactylosternum abdominale which is apparently colonising the UK from Madeira. This terrestrial beetle is associated with organic rubbish and has been found in silage clamps, compost and animal manure so its presence in a chalk stream is difficult to account for, unless it is associated with the works on the far side of the river where some dredged material has been dumped onto the bank by the landowner (not TWC).
Photo 5. Dactylosternum abdominale
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References Aquilina, R. (2019). Macroinvertebrate Survey of watercress farm outflows, Alresford, Hants. Clarke,R.T., Furse, M.T., Gunn, R.J.M., Winder, J.M. and Wright, J.F. (2002). Sampling variation in macroinvertebrate data and implications for river quality indices. Freshwater Biology 47, 1735-1751. Environment Agency. (2012). Freshwater macro-invertebrate sampling in rivers. Operational instruction 018_08. Environment Agency. Environment Agency. (2012). Freshwater macro-invertebrate analysis of riverine samples. Operational instruction 024_08. Environment Agency. Environment Agency. (2014). Walley Hawkes Paisley Trigg (WHPT) index of river invertebrate quality and its use in assesing ecological status. Brief Guide version 5. Paisley,M.F., Trigg,D.J. and Walley,W.J. (2013). Revision of the Biological Monitoring Working Party (BMWP) score system: derivation of present-only and abundancerelated scores from field data. River Research and Appications. 30: 887-904.
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Appendix 1 Species recorded. Group
BMWP family
Species
Common name
Dendrocoelidae Dugesiidae Planariidae Planariidae Planariidae Hydrobiidae Physidae Lymnaeidae Lymnaeidae Planorbidae Planorbidae Planorbidae Planorbidae Valvatidae Valvatidae Ancylidae Sphaeridae Asellidae Gammaridae Erpobdellidae Erpobdellidae Glossiphonidae Glossiphonidae Glossiphonidae
Dendrocoelum lacteum Dugesia polychroa gr. Polycelis felina Polycelis nigra Polycelis tenuis Potamopyrgus antipodarum Physa fontinalis Lymnaea palustris Radix balthica Anisus leucostoma Anisus vortex Bathyomphalus contortus Gyraulus albus Valvata cristata Valvata piscinalis Ancylus fluviatilis Pisidium sp. Asellus aquaticus Gammarus pulex Erpobdella octoculata Trocheta subviridis Glossiphonia complanata Glossiphonia heteroclita Helobdella stagnalis
Flatworm Flatworm Flatworm Flatworm Flatworm Jenkins spire snail Bladder snail Marsh Pond snail Wandering snail Button ramshorn Whirlpool ramshorn Twisted ramshorn White ramshorn Flat valve snail Common valve snail River limpet Pea mussel Water slater Freshwater shrimp Leech Leech Leech Leech Leech
Status
Abundance
BMWP
WHPT
4 7
5
5.4
7
3
2.7
29 2 5 2
3
2.5
3
3.2
2 23 1 123 1606 48
3 6 3 3 6 3
3.3 5.5 4.4 0.8 3.9 2.0
Bishops Sutton Tricladida Tricladida Tricladida Tricladida Tricladida Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Crustacea Crustacea Hirudinea Hirudinea Hirudinea Hirudinea Hirudinea
=Lymnaea peregra
3 7
Group
BMWP family
Species
Common name
Hirudinea Hirudinea Plecoptera Plecoptera Plecoptera Ephemeroptera Ephemeroptera Ephemeroptera
Glossiphonidae Piscicolidae Nemouridae Leuctridae Leuctridae Ephemerellidae Baetidae Baetidae
Theromyzon tessulatum Piscicola geometra Nemurella picteti Leuctra fusca Leuctra nigra Serratella ignita Baetis rhodani Baetis vernus
Duck leech Fish leech Stonefly Stonefly Stonefly Blue-winged Olive Large Dark Olive Medium Olive
Ephemeroptera Hemiptera Hemiptera Hemiptera Hemiptera Coleoptera Coleoptera
Caenidae Gerridae Veliidae Corixidae Corixidae Haliplidae Haliplidae
Caenis sp. Gerris sp. Velia caprai Sigara dorsalis Brychius elevatus Haliplus lineatocollis
Mayfly Water skater Water cricket Lesser water boatman Lesser water boatman Crawling water beetle Crawling water beetle
Coleoptera Coleoptera Coleoptera
Haliplidae Dytiscidae Dytiscidae
Haliplus sp. Nebrioporus elegans Oreodytes sanmarkii
Crawling water beetle Diving beetle Diving beetle
Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera
Dytiscidae Elmidae Elmidae Elmidae Scirtidae
Elmis aenea Limnius volckmari Riolus subviolaceus Elodes sp.
Diving beetle Riffle beetle Riffle beetle Riffle beetle Marsh beetle
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Status
Abundance
BMWP
WHPT
1 1
3 4
2.5 5.2
32 118 235
10
8.5
4
7.2
2 7 2
5
3.7
20 7 37
5
3.4
2 53 1
5
4.8
5
7.4
early instars not identifiable to species nymph
nymph
larvae not identifiable to species
larvae not identifiable to species larva and adults larvae larva and adults larva
1
6.9
Group
BMWP family
Species
Common name
Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera
Hydropsychidae Hydropsychidae Polycentropodidae Rhyacophilidae Glossosomatidae Brachycentridae Hydroptilidae
Diplectrona felix Hydropsyche siltalai Plectrocnema conspersa Rhyacophila dorsalis Agapetus fuscipes Brachycentrus subnubilis Agraylea multipunctata
Caseless caddis Caseless caddis Caseless caddis Caseless caddis Saddle-case caddis Cased caddis Cased caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera
Hydroptilidae Leptoceridae Limnephilidae Limnephilidae Limnephilidae Goeridae Odontoceridae Sericostomatidae Ceratopogonidae Chironomidae Ephydridae Empididae Muscidae Psychodidae Sciomyzidae
Oxyethira sp. Mystacides sp. Drusus annulatus Limnephilus lunatus
Cased caddis Long-horned caddis Cased caddis Cased caddis Cased caddis Cased caddis Silver sedge Cased caddis Biting midge Non-biting midge Shore fly Dance fly Stable fly Moth fly Snail-killing flies
Diptera Diptera Diptera
Simulidae Stratiomyidae Tipulidae
Simulium sp.
Silo nigricornis Odontocerum albicorne Sericostoma personatum
Limnophora riparia Pericoma sp.
Blackflies Soldier fly cranefly
19
Status
larvae not identifiable to species larvae not identifiable to species
Abundance
BMWP
WHPT
2 11 7
7 7
8.2 9.2 7.8
6
6.8
1 4
7 10
5.9 8.8
2 7 14
10
8.9 5.4 1.3
19 366 2
pupa
larvae larvae pupa larvae larvae larvae larvae early instars not identifiable to species larvae larvae
2
1
132 1
4.5
5
5.8 3.6
Group
BMWP family
Species
Common name
Status
Diptera Others Others
Tipulidae(Pediciidae) Hydracarina Oligochaeta
Dicranota sp.
cranefly Water mite True worms
larvae
20
Abundance
BMWP
WHPT
29 49
1
2.3
Group
BMWP family
Species
Common name
Tricladida Tricladida Tricladida Tricladida Tricladida Mollusca Mollusca Mollusca Mollusca Mollusca
Dendrocoelidae Dugesiidae Planariidae Planariidae Planariidae Physidae Lymnaeidae Lymnaeidae Lymnaeidae Planorbidae
Dendrocoelum lacteum Dugesia polychroa gr. Polycelis felina Polycelis nigra Polycelis tenuis Physa fontinalis Galba truncatula Stagnicola palustris Radix balthica Anisus leucostoma
Mollusca
Planorbidae
Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Crustacea Crustacea Hirudinea Hirudinea
Planorbidae Planorbidae Planorbidae Valvatidae Valvatidae Ancylidae Sphaeridae Asellidae Gammaridae Erpobdellidae Erpobdellidae
Hirudinea
Glossiphonidae
Anisus vortex Bathyomphalus contortus Gyraulus crista Hippeutis complanata Valvata cristata Valvata piscinalis Ancylus fluviatilis Pisidium sp. Asellus aquaticus Gammarus pulex Erpobdella octoculata Trocheta subviridis Glossiphonia complanata
Flatworm Flatworm Flatworm Flatworm Flatworm Bladder snail Dwarf pond snail Marsh snail Wandering snail Button ramshorn Whirlpool ramshorn
Status
Abundance
BMWP
WHPT
Above Drayton
Twisted ramshorn Nautilus ramshorn Flat ramshorn Flat valve snail Valve snail River limpet Pea mussel Water slater Freshwater shrimp Leech Leech Leech
2
=Lymnaea palustris =Lymnaea peregra
1 4 4
5 3
4.7 2.7
93
3
2.5
1
3
3.2
4 9 4 15 580 24
3 3 3 3 6 3
3.3 5.8 4.4 2.3 4.5 2.0
12
21
2.8
Group
BMWP family
Species
Common name
Hirudinea Hirudinea Hirudinea Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Plecoptera Plecoptera Megaloptera Hemiptera Hemiptera Hemiptera Coleoptera Coleoptera Coleoptera
Glossiphonidae Glossiphonidae Piscicolidae Ephemerellidae Baetidae Baetidae Baetidae Caenidae Ephemeridae Nemouridae Nemouridae Sialidae Corixidae Gerridae Veliidae Haliplidae Haliplidae Haliplidae
Helobdella stagnalis Theromyzon tessulatum Piscicola geometra Serratella ignita Baetis rhodani Baetis vernus Cloeon dipterum Caenis rivulorum Ephemera danica Nemurella picteti Nemoura cinerea Sialis lutaria Sigara dorsalis Gerris sp. Velia caprai Brychius elevatus Haliplus lineatocollis Haliplus sibiricus
Leech
Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera
Haliplidae Dytiscidae Dytiscidae Dytiscidae Hydrophilidae Hydrophilidae Elmidae Elmidae Elmidae
Haliplus sp. Nebrioporus elegans Oreodytes sanmarkii Anacaena limbata Helophorus brevipalpis Elmis aenea Limnius volckmari Riolus subviolaceus
Status
Fish leech Blue-winged Olive Large Dark Olive Medium Olive Pond olive Mayfly Greendrake Stonefly Stonefly Alderfly Lesser water boatman Water skater nymph Water cricket Crawling water beetle Crawling water beetle Crawling water beetle Crawling water beetle larvae not identifiable to species Diving beetle Diving beetle Diving beetle larvae not identifiable to species Scavenger water beetle Scavenger water beetle Riffle beetle larva and adults Riffle beetle larva and adults Riffle beetle larva and adults
22
Abundance
BMWP
WHPT
68
3
2.5
7 116 174
10
7.9
4
7.2
2
10
8.3
1
5
3.7
1
5
3.6
32 2 1 1 7
5
4.8
5
5.8
5
5.3
Group
BMWP family
Species
Common name
Status
Coleoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera
Scirtidae Hydropsychidae Psychomyiidae Rhyacophilidae Glossosomatidae Hydroptilidae Hydroptilidae Leptoceridae Limnephilidae Limnephilidae Limnephilidae Limnephilidae
Marsh beetle Caseless caddis Caseless caddis Caseless caddis Saddle-case caddis Cased caddis Cased caddis Long-horned caddis Cased caddis Cased caddis Cased caddis Cased caddis
larva
Trichoptera Trichoptera Trichoptera
Limnephilidae Limnephilidae Limnephilidae
Microcara testacea Hydropsyche siltalai Tinodes waeneri Rhyacophila dorsalis Agapetus fuscipes Hydroptila sp. Oxyethira sp. Adicella reducta Anabola nervosa Drusus annulatus Halesus digitatus Limnephilus lunatus Melampophylax mucoreus Micropterna lateralis Potamophylax latipennis
Trichoptera Trichoptera Trichoptera Trichoptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera
Limnephilidae Goeridae Odontoceridae Sericostomatidae Anthomyzidae Ceratopogonidae Chironomidae Culicidae Dixidae Empididae Ephydridae Muscidae
larvae not identifiable to species larvae not identifiable to species
Cased caddis Cased caddis Cased caddis
Silo nigricornis Odontocerum albicorne Sericostoma personatum
Cased caddis Cased caddis Silver sedge Cased caddis
Dixa nebulosa Clinocera sp. Setacera sp. Limnophora riparia
Biting midge Non-biting midge Mosquito Meniscus midge Dance fly Shore fly Stable fly
23
Abundance
BMWP
WHPT
3 1 19 15 31
8 7
5.8 8.1 7.6
6
6.5
23
7
6.9
2
5.5 -0.9
early instars not identifiable to species
larvae larvae larvae larvae larvae larvae larvae larvae
12 263
1
7.0
3
4.0
Group
BMWP family
Species
Common name
Status
Diptera Diptera
Psychodidae Sciomyzidae
Pericoma sp.
Moth fly Snail-killing flies
Diptera Diptera Diptera Diptera Diptera Diptera Others Others
Simulidae Simulium sp. Stratiomyidae Syrphidae Tipulidae Tipulidae (Limoniidae) Tipulidae(Pediciidae) Dicranota sp. Hydracarina Oligochaeta
larvae larvae early instars not identifiable to species larvae larvae larvae larvae larvae
Blackflies Soldier fly Hover fly cranefly cranefly cranefly Water mite True worms
24
Abundance
BMWP
11 1 29
3.3 3.4 5
2 17 15 20 141
WHPT
6.1 1.9
5
6.9
1
1.4
Group
BMWP family
Species
Common name
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Dugesiidae
Dugesia polychroa gr.
Flatworm
Tricladida
Planariidae
Polycelis felina
Flatworm
Tricladida
Planariidae
Polycelis nigra
Flatworm
Tricladida
Planariidae
Polycelis tenuis
Flatworm
Mollusca
Physidae
Physa fontinalis
Bladder snail
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
Mollusca
Planorbidae
Anisus leucostoma
Mollusca
Planorbidae
Mollusca
Planorbidae
Anisus vortex Bathyomphalus contortus
Button ramshorn Whirlpool ramshorn
Mollusca
Planorbidae
Gyraulus crista
Nautilus ramshorn
Mollusca
Planorbidae
Hippeutis complanata
Flat ramshorn
Mollusca
Valvatidae
Valvata cristata
Flat valve snail
Mollusca
Valvatidae
Valvata piscinalis
Valve snail
Mollusca
Ancylidae
Ancylus fluviatilis
River limpet
Mollusca
Sphaeridae
Pisidium sp.
Pea mussel
Crustacea
Asellidae
Asellus aquaticus
Water slater
Crustacea
Niphargidae
Niphargus aquilex
Cave shrimp
Crustacea
Gammaridae
Gammarus pulex
Freshwater shrimp
Hirudinea
Erpobdellidae
Erpobdella octoculata
Leech
Status
Abundance
BMWP
WHPT
7
5
3.0
1 4 1
5 3 3
4.7 2.7 3.6
26
3
3.0
8 10 35
6
5.8
3
3.5
3
2.3
440 22
6 3
4.6 2.0
Below Drayton
=Lymnaea peregra
Twisted ramshorn
25
Group
BMWP family
Species
Common name
Status
Hirudinea
Erpobdellidae
Leech
Hirudinea
Glossiphonidae
Trocheta subviridis Glossiphonia complanata
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Caenidae
Caenis rivulorum
Mayfly
Ephemeroptera
Ephemeridae
Ephemera danica
Greendrake
Megaloptera
Sialidae
Sialis lutaria
Odonata
Calopterygidae
Calopteryx virgo
Alderfly Beautiful demoiselle
Hemiptera
Corixidae
Sigara dorsalis
Lesser water boatman
Hemiptera
Gerridae
Gerris sp.
Water skater
Hemiptera
Veliidae
Velia caprai
Water cricket
Coleoptera
Haliplidae
Brychius elevatus
Crawling water beetle
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sibiricus
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle Crawling water beetle larvae not identifiable to species
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Leech
26
Abundance
BMWP
WHPT
64
3
2.5
2 1 1 3 4 16
4 10 7 10
5.2 9.3 8.7 7.9
4
5.9
16
4
4.4
2
8
5.9
1 25
5 5
3.4 4.8
nymph
Group
BMWP family
Species
Common name
Status
Abundance
Coleoptera
Dytiscidae
Coleoptera
Hydrophilidae
Anacaena globulus
Scavenger water beetle
Coleoptera
Hydrophilidae
Helophorus brevipalpis
Scavenger water beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
larva and adults
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larva and adults
Coleoptera
Elmidae
Riolus subviolaceus
Riffle beetle
larva and adults
Coleoptera
Scirtidae
Microcara testacea
Marsh beetle
larva
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Psychomyiidae
Lype reducta
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
larvae not identifiable to species
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
larvae not identifiable to species
Trichoptera
Leptoceridae
Adicella reducta
Long-horned caddis
Trichoptera
Beraeidae
Beraeodes minutus
Cased caddis
Trichoptera
Limnephilidae
Anabola nervosa
Cased caddis
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Halesus digitatus
Cased caddis
Trichoptera
Limnephilidae
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus Melampophylax mucoreus
Diving beetle
larvae
1
Trichoptera
Limnephilidae
Micropterna lateralis
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
Cased caddis
Cased caddis
27
early instars not identifiable to species
BMWP
WHPT
100 5 1
5
8.3
1 3 1 2
7 7
8.1 7.8
6
6.5
17
10
7.3
7
7
5.9
Group
BMWP family
Species
Common name
Status
Abundance
BMWP
WHPT
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
1
10
8.9
Diptera
Anthomyzidae
Diptera
Ceratopogonidae
Biting midge
larvae
2
5.4 1.3
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Dixidae
Meniscus midge
larvae
Diptera
Ephydridae
Shore flies
pupae
Diptera
Muscidae
Limnophora riparia
Stable fly
pupae
Diptera
Psychodidae
Pericoma sp.
Moth fly
larvae
2 3
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Blackflies
larvae early instars not identifiable to species
30
5
6.1
Diptera
Stratiomyidae
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae (Limoniidae)
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
5
5.4
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
1 42 71
1
2.3
larvae
Dixa nebulosa
Simulium sp.
Dicranota sp.
28
5 61
4.0 4.5
Group
BMWP family
Species
Common name
Status
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Dugesiidae
Dugesia polychroa gr.
Flatworm
Tricladida
Planariidae
Polycelis felina
Flatworm
Tricladida
Planariidae
Polycelis nigra gr.
Flatworm
Tricladida
Planariidae
Polycelis tenuis
Flatworm
Mollusca
Physidae
Physa fontinalis
Mollusca
Lymnaeidae
Galba truncatula
Bladder snail Dwarf pond snail
=Lymnaea truncatula
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
=Lymnaea peregra
Mollusca
Lymnaeidae
Stagnicola palustris
=Lymnaea palustris
Mollusca
Planorbidae
Anisus leucostoma
Mollusca
Planorbidae
Anisus vortex
Mollusca
Planorbidae
Bathyomphalus contortus
Marsh snail Button ramshorn Whirlpool ramshorn Twisted ramshorn
Mollusca
Valvatidae
Valvata cristata
Mollusca
Valvatidae
Valvata piscinalis
Flat valve snail Common valve snail
Mollusca
Ancylidae
Acroloxus lacustris
Lake limpet
Mollusca
Ancylidae
Ancylus fluviatilis
River limpet
Mollusca
Sphaeridae
Pisidium sp.
Pea mussel
Abundance
BMWP
WHPT
7
5
3.0
53
5
5.4
2
3
2.7
1 16
3
2.5
1 15
3
3.0
3 1 22 2
3
3.1 3.6 5.5 4.4
Manor Farm
29
17 3
6 3
Group
BMWP family
Species
Common name
Crustacea
Asellidae
Asellus aquaticus
Crustacea
Gammaridae
Gammarus pulex
Water slater Freshwater shrimp
Hirudinea
Erpobdellidae
Erpobdella octoculata
Leech
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Ephemeroptera
Ephemerellidae
Serratella ignita
Stonefly Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Caenidae
Caenis luctuosa
Mayfly
Ephemeroptera
Caenidae
Caenis rivulorum
Mayfly
Ephemeroptera
Ephemeridae
Ephemera danica
Greendrake
Ephemeroptera
Heptageniidae
Rithrogena semicolorata
Olive upright
Megaloptera
Sialidae
Sialis lutaria
Alderfly
Hemiptera
Gerridae
Gerris sp.
Water skater
nymph
Hemiptera
Veliidae
Velia caprai
Water cricket
nymph
Hemiptera
Corixidae
Water boatman
nymph
Coleoptera
Haliplidae
Haliplus lineatocollis
Status
Crawling water beetle
30
Abundance
BMWP
WHPT
134
3
0.8
3598 47
6 3
3.9 2.0
3 14 2
3
2.5
4
7
8.7
15
10
8.5
323 36
4
7.2
1
7
6.5
1
4
4.2
1
5
3.7
Group
BMWP family
Species
Common name
Status
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
larvae not identifiable to species
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Coleoptera
Hydrophilidae
Dactylosternum abdominale
Scavenger water beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
larva and adults
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larvae
Coleoptera
Elmidae
Riolus sp.
Riffle beetle
larvae
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Diplectrona felix
Caseless caddis
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Caseless caddis Saddle-case caddis
Trichoptera
Hydroptilidae
Agraylea sp.
Cased caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Ithytrichia sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Trichoptera
Leptoceridae
Adicella reducta
Cased caddis Long-horned caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Melampophylax mucoreus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
Cased caddis
31
Abundance
BMWP
WHPT
1 50 2 1
5
5.8
5
7.4
3
5
5.8
8
7
8.1
174
7.2
larvae not identifiable to species
19
larvae not identifiable to species
90
6
6.8
3 9
7
6.9
Group
BMWP family
Species
Common name
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Ceratopogonidae
larvae
7
Diptera
Chironomidae
larvae
31
Diptera
Dixidae
Dixa sp.
Biting midge Non-biting midge Meniscus midges
larvae
3
7.0
Diptera
Empididae
Dance fly
larvae
Diptera
Ephydridae
Shore fly
pupa and larva
Diptera
Muscidae
Limnophora riparia
Stable fly
pupa and larva
Diptera
Psychodidae
Pericoma sp. + Psychoda sp.
Moth fly
larvae
3 2
4.0 4.5
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Blackflies
larvae early instars not identifiable to species
57
5
6.1
Diptera
Stratiomyidae
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
Dicranota sp.
cranefly
larvae
2
5
5.4
Diptera
Tipulidae(Pediciidae)
Pedicia sp.
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
7 65
1
2.3
Simulium ornatum gr.
32
Status
Abundance
BMWP
WHPT
35
10
8.8
5.4 2
1.3
