Macroinvertebrate Survey of watercress farm outflows, Alresford , Autumn 2021
Report prepared by Robert Aquilina MSc MCIEEM
October 2021
Macroinvertebrate survey of watercress farm outflows, Alresford, Autumn 2021
Robert Aquilina MSc MCIEEM
October 2021
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 .............................................................................................................................................. 6 Locations ......................................................................................................................................... 7
Results ................................................................................................................. 10 Discussion ............................................................................................................ 12 References ........................................................................................................... 13 Appendix 1 Species recorded with abundance. ..................................................... 14
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Summary
Macroinvertebrate surveys of outflows from Bishop’s Sutton, above and below settlement ponds at 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 and 2020 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. All the significant indices had increased from the previous year, probably due to weather conditions as the changes appeared across all four sites.
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Introduction
The purpose of this survey was to repeat the assessments carried out in previous years 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, 2020). 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 Tuesday 7th September 2021 and Manor Farm and Bishops Sutton on Wednesday 22nd September 2021. The dates follow those of the surveys from the previous year. 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 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.
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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 and counted. 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.
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.
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Abundance category Numerical abundance AB1 1-9 AB2 10 -99 AB3 100 - 999 AB4 >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 (number of taxa contributing to the score) 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 (95% cover) to an even greater extent than the previous year.
Photo 1. Bishops Sutton.
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The Drayton Farm – below settlement ponds 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.
Photo 2. Below Drayton Farm The Drayton Farm – above settlement ponds 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. Ranunculus growth was reduced this year compared to gravel (40:60%) which appears to be a continuing trend from the domination by Ranunculus in 2019.
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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 (Common reed, Watercress and Water Speedwell) similar to last year. Again there was very little in-channel Ranunculus.
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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, 2020 and 2021. All the significant indices have increased this year compared with last year and compared with most of the 2019 results as well (only Manor Farm has a higher previous WHPT score from 2019). Overall abundance is generally down on previous years but this is a highly variable result and is not a significant measure of water quality or biodiversity. Overall number of species and number of contributing species (to the indices) have also increased (or remained the same in the case of Drayton Farm above settlement ponds ). As a consequence, this years’ results are higher than the seasonal means so these have not been presented this year.
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Site
Date
Bishop’s Sutton
3/9/19 Autumn 15/9/20 Autumn 22/9/21 Autumn 3/9/19 Autumn
54 46 57 41
2488 3035 3252 918
38 32 41 31
201.9 161.8 225.4 160.8
5.31 5.06 5.50 5.19
7/9/20 Autumn 7/9/21 Autumn 22/8/18 Summer
40 48 46
1043 866 1966
34 38 32
175.0 198.2 149.4
5.15 5.22 4.67
3/9/19 Autumn 45 1242 33 7/9/20 Autumn 43 1772 35 7/9/21 Autumn 43 1281 35 3/9/19 Autumn 53 2699 38 15/9/20 Autumn 47 4894 35 22/9/21 Autumn 54 3332 38 Values showing an increase are highlighted in blue
165.4 160.8 168.2 211.6 174.0 200.8
5.01 4.59 4.81 5.57 4.97 5.28
Drayton Farm below settlement ponds
Drayton Farm above settlement ponds
Manor Farm
Season
# species
Abundance Ntaxa
WHPT ASPT
Table 2. Results summary
Because the increases are across all the sites, it is likely that favourable weather conditions will have contributed to the results, as well as the usual seasonal and sampling variations. 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 a mix of responses across the sites which would be expected as there is no overall trend to the results year on year. Site
Sept 2019 Sept 2020 Sept 2021
Bishop’s Sutton Drayton below settlement ponds Drayton above settlement ponds Manor Farm
928 364 159 1341
1606 440 580 3598
1708 139 127 1560
Table 3. Gammarus counts
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Discussion
The results illustrate the natural variation between years and, because the enhanced WHPT scores are across all sites, it is suspected to be due to the weather conditions and lack of vegetation removal rather than any significant change in water quality.
WHPT scores 240 220 200 180 160 140
Manor Farm
Above Drayton
Below Drayton
44409
44348
44287
44228
44166
44105
44044
43983
43922
43862
43800
43739
43678
43617
43556
43497
43435
43374
43313
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Bishops Sutton
Graph 1. Annual WHPT scores The relative cover of the habitats present at each site were all similar to the previous year and possibly reflect some constancy of environment which may have influenced scores positively. Gammarus counts show no trend across sites.
Overall it is concluded that three factors are potentially reflected in the enhanced scores of 2021:
Weather conditions that have been favourable (a cooler than average summer). Vegetation removal (which significantly disturbs the invertebrate community) was not carried out this year. Salad washing plant at Drayton Farm paused operation this year which might be expected to affect two of the survey sites but not the other two which are on separate streams.
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References Aquilina, R. (2019). Macroinvertebrate Survey of watercress farm outflows, Alresford, Hants. Aquilina, R. (2020). Macroinvertebrate Survey of watercress farm outflows, Alresford, Autumn, 2020. 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 abundance-related scores from field data. River Research and Appications. 30: 887-904.
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Appendix 1 Species recorded with abundance. 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
Hydrobiidae
Potamopyrgus antipodarum
Jenkins spire snail
Mollusca
Physidae
Physa fontinalis
Bladder snail
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
Mollusca
Lymnaeidae
Stagnicola fuscus
Marsh Pond snail
Mollusca
Planorbidae
Anisus leucostoma
Button ramshorn
Mollusca
Planorbidae
Anisus vortex
Whirlpool ramshorn
Mollusca
Planorbidae
Bathyomphalus contortus
Twisted ramshorn
Mollusca
Planorbidae
Gyraulus albus
White ramshorn
Mollusca
Valvatidae
Valvata cristata
Flat valve snail
Mollusca
Valvatidae
Valvata piscinalis
Common valve snail
Mollusca
Ancylidae
Ancylus fluviatilis
River limpet
Mollusca
Sphaeridae
Pisidium sp.
Pea mussel
Crustacea
Asellidae
Asellus aquaticus
Water slater
Crustacea
Gammaridae
Gammarus pulex
Freshwater shrimp
Hirudinea
Erpobdellidae
Erpobdella octoculata
Leech
Status
Abundance
Bishops Sutton
3
=Lymnaea peregra
77 83 2 23
2 41 5 163 1708 61
Group
BMWP family
Species
Common name
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Alboglossiphonia heteroclita
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Duck leech
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Leuctridae
Leuctra nigra
Stonefly
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Caenidae
Caenis sp.
Mayfly
Megaloptera
Sialidae
Sialis lutaria
Alderfly
Hemiptera
Gerridae
Gerris sp.
Water skater
Hemiptera
Veliidae
Velia caprai
Water cricket
Hemiptera
Corixidae
Sigara dorsalis
Lesser water boatman
Hemiptera
Corixidae
Coleoptera
Haliplidae
Brychius elevatus
Crawling water beetle
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Status
Abundance
1 3 38 6 1 2 1 9 279 246 early instars not identifiable to species
3
Lesser water boatman
15
nymph
nymph
2 9
larvae not identifiable to species
18
Group
BMWP family
Species
Common name
Coleoptera
Dytiscidae
Nebrioporus elegans
Diving beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Coleoptera
Dytiscidae
Coleoptera
Hydrophilidae
Anacaena globulus
Water beetle
Coleoptera
Hydrophilidae
Laccobius bipunctatus
Water beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
larva and adults
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larvae
Coleoptera
Elmidae
Riolus subviolaceus
Riffle beetle
larva and adults
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Diplectrona felix
Caseless caddis
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Polycentropodidae
Plectrocnema conspersa
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Brachycentridae
Brachycentrus subnubilis
Cased caddis
Trichoptera
Hydroptilidae
Agraylea multipunctata
Cased caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
larvae not identifiable to species
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
larvae not identifiable to species
Trichoptera
Beraeidae
Beraeodes minutus
Cased caddis
21 57 1
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
pupa
Trichoptera
Goeridae
3 6 3
Diving beetle
Cased caddis Silo nigricornis
Cased caddis
16
Status
Abundance 4 18
larvae not identifiable to species
4 1 1 76 1 8 8 2
16 3
Group
BMWP family
Species
Common name
Status
Abundance
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge Biting midge
larvae
Non-biting midge
larvae
Meniscus midges
larvae
1 2 1 89 1
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Ceratopogonidae
Diptera
Chironomidae
Diptera
Dixidae
Diptera
Ephydridae
Shore fly
pupa
Diptera
Empididae
Dance fly
larvae
Diptera
Muscidae
Limnophora riparia
Stable fly
larvae
Diptera
Psychodidae
Pericoma sp.
Moth fly
larvae
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Simulium sp.
Blackflies
larvae early instars not identifiable to species
Diptera
Stratiomyidae
Oxycera sp.
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Dixa nebulosa
Dicranota sp.
17
17 8 5
60 4 3 1 8 33
Group
BMWP family
Species
Common name
Status
Abundance
Drayton Farm above settlement ponds 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
Galba truncatula
Dwarf pond snail
Mollusca
Lymnaeidae
Stagnicola palustris
Marsh snail
=Lymnaea palustris
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
=Lymnaea peregra
Mollusca
Planorbidae
Anisus leucostoma
Button ramshorn
Mollusca
Planorbidae
Anisus vortex
Whirlpool ramshorn
Mollusca
Planorbidae
Bathyomphalus contortus
Twisted 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
18
1
2 1
37
3 8 1 1 5 127 18
Group
BMWP family
Species
Common name
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Duck leech
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Baetidae
Cloeon dipterum
Pond olive
Ephemeroptera
Caenidae
Caenis rivulorum
Mayfly
Ephemeroptera
Ephemeridae
Ephemera danica
Greendrake
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Plecoptera
Nemouridae
Nemoura cinerea
Stonefly
Megaloptera
Sialidae
Sialis lutaria
Alderfly
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
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Nebrioporus elegans
Diving beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Status
Abundance
4 43
19
17 224 79
1
3 nymph
1
larvae not identifiable to species
14
Group
BMWP family
Species
Common name
Status
Coleoptera
Dytiscidae
Diving beetle
larvae not identifiable to species
Coleoptera
Hydrophilidae
Anacaena limbata
Scavenger water beetle
Coleoptera
Hydrophilidae
Helophorus brevipalpis
Scavenger water beetle
Coleoptera
Hydrophilidae
Coleoptera
Elmidae
Coleoptera
Scavenger water beetle
larvae not identifiable to species
Elmis aenea
Riffle beetle
larva and adults
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
Tinodes waeneri
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
Trichoptera
Leptoceridae
Adicella reducta
Long-horned caddis
Trichoptera
Limnephilidae
Anabola nervosa
Cased caddis
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Halesus digitatus
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Melampophylax mucoreus
Cased caddis
Trichoptera
Limnephilidae
Micropterna lateralis
Cased caddis
20
Abundance
11
2 6 1
1 13 larvae not identifiable to species larvae not identifiable to species
33 62
6
Group
BMWP family
Species
Common name
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Anthomyzidae
Diptera
Ceratopogonidae
Biting midge
larvae
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Culicidae
Mosquito
larvae
Diptera
Dixidae
Dixa nebulosa
Meniscus midge
larvae
Diptera
Empididae
Clinocera sp.
Dance fly
larvae
Diptera
Ephydridae
Setacera sp.
Shore fly
larvae
Diptera
Muscidae
Limnophora riparia
Stable fly
larvae
Diptera
Psychodidae
Pericoma sp.
Moth fly
larvae
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Blackflies
larvae early instars not identifiable to species
Diptera
Stratiomyidae
Soldier fly
larvae
Diptera
Syrphidae
Hover fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae (Limoniidae)
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Cased caddis
Status
Abundance
early instars not identifiable to species
larvae
Simulium sp.
Dicranota sp.
21
8 314 17 6 14 1 4 17 1 36
8 4 16 110
Group
BMWP family
Species
Common name
Status
Abundance
Drayton Farm below settlement ponds 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
Galba truncatula
Dwarf pond snail
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
Mollusca
Planorbidae
Anisus leucostoma
Button ramshorn
Mollusca
Planorbidae
Anisus vortex
Whirlpool ramshorn
Mollusca
Planorbidae
Bathyomphalus contortus
Twisted 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
22
1
=Lymnaea peregra
2 1 1 2 2 32 1
6 12 14 139 8
Group
BMWP family
Species
Common name
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Duck leech
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Leuctridae
Leuctra geniculata
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
Alderfly
Odonata
Calopterygidae
Calopteryx virgo
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
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Status
Abundance
30 4
23
1 1 1 7 51 113
4 1 nymph
1 2
larvae not identifiable to species
5 7
Group
BMWP family
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
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Melampophylax mucoreus
Cased caddis
Trichoptera
Limnephilidae
Micropterna lateralis
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
Species
Common name
Status
Diving beetle
larvae not identifiable to species
Cased caddis
24
Abundance 2
102 1
1 2 5 6 11
13 7 early instars not identifiable to species
Group
BMWP family
Species
Common name
Status
Abundance
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Anthomyzidae
Diptera
Ceratopogonidae
Biting midge
larvae
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
1 1
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Simulium sp.
Blackflies
larvae early instars not identifiable to species
76
Diptera
Stratiomyidae
Oxycera nigricornis
Delicate Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae (Limoniidae)
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
2 larvae
Dixa nebulosa
Dicranota sp.
25
6 29 2
1
4 40 105
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
Bladder snail
Mollusca
Lymnaeidae
Galba truncatula
Dwarf pond snail
=Lymnaea truncatula
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
=Lymnaea peregra
Mollusca
Lymnaeidae
Stagnicola palustris
Marsh snail
=Lymnaea palustris
Mollusca
Planorbidae
Anisus leucostoma
Button ramshorn
Mollusca
Planorbidae
Anisus vortex
Whirlpool ramshorn
Mollusca
Planorbidae
Bathyomphalus contortus
Twisted ramshorn
Planorbidae
Planorbarius corneus
Great ramshorn
Mollusca
Valvatidae
Valvata cristata
Flat valve snail
Mollusca
Valvatidae
Valvata piscinalis
Common valve snail
Mollusca
Ancylidae
Acroloxus lacustris
Lake limpet
Mollusca
Ancylidae
Ancylus fluviatilis
River limpet
Mollusca
Sphaeridae
Sphaerium corneum
Horny orb mussel
Mollusca
Sphaeridae
Pisidium sp.
Pea mussel
Crustacea
Asellidae
Asellus aquaticus
Water slater
Crustacea
Gammaridae
Gammarus pulex
Freshwater shrimp
Abundance
Manor Farm
26
7 3 1 8 34 12 42 23 7 1 17 4 79 1 6 297 1560
Group
BMWP family
Species
Common name
Status
Abundance
Hirudinea
Erpobdellidae
Erpobdella octoculata
Leech
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Duck leech
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
10
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
15
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
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
81 14 17 2
319 60 3 1 2
27
larvae not identifiable to species
3
larva and adults
39
Group
BMWP family
Species
Common name
Status
Abundance
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larvae
3
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
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Agraylea sexmaculata
Cased caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
larvae not identifiable to species
Trichoptera
Hydroptilidae
Ithytrichia 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
Limnephilidae
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus Melampophylax mucoreus
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Limnephilidae
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Odontoceridae
Odontocerum albicorne
Silver sedge
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Ceratopogonidae
Biting midge
larvae
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Dixidae
Meniscus midges
larvae
Diptera
Empididae
Dance fly
larvae
Dixa sp.
28
86
1 1
Cased caddis
Cased caddis
5 5 49 1 43
early instars not identifiable to species
2 30 4 11 15 114 1 1
Group
BMWP family
Diptera
Ephydridae
Diptera
Muscidae
Diptera
Psychodidae
Diptera
Sciomyzidae
Diptera
Simulidae
Diptera
Species
Common name
Status
Shore fly
pupa and larva
Stable fly
pupa and larva
5
Moth fly
larvae
8
Snail-killing flies Blackflies
larvae early instars not identifiable to species
82
Stratiomyidae
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
Dicranota sp.
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
Pedicia sp.
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Limnophora riparia Pericoma sp. + Psychoda sp.
Simulium ornatum gr.
Abundance
1 8 11 177
29