Macroinvertebrate Survey of watercress farm outflows, Alresford , Hants 2021
Report prepared by Robert Aquilina MSc MCIEEM
May 2021
Macroinvertebrate survey of watercress farm outflows, Alresford, Hants 2021
Robert Aquilina MSc MCIEEM
May 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
2
Table of contents Summary .............................................................................................................. 4 Introduction .......................................................................................................... 5 Methods ............................................................................................................... 5 BMWP ............................................................................................................................................. 6 WHPT .............................................................................................................................................. 7 Locations ......................................................................................................................................... 7
Results ................................................................................................................. 11 Conclusions .......................................................................................................... 15 References ........................................................................................................... 16 Appendix 1 Species recorded. ............................................................................... 17
3
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 a year on to investigate any changes and identify any potential water quality issues. The species present were typical of a chalk stream, with good diversity and high water quality scores. A complete list of species is presented together with abundance and diversity (WHPT) scores. The indices indicate very similar biodiversity and water quality to 2020 for two sites with slight reduction in scores at the other two sites although these are still higher than the scores from 2019. The differences are accounted for by variation in sampling efficacy and natural environmental variation due to weather. A nationally scarce moss beetle, Ochthebius exsculptus, was found at two sites. This is the first record in southern England in some decades and the first for Hampshire. It is more frequent in the north of England and Scotland.
4
Introduction
The purpose of this survey was to repeat the annual assessments 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 similar to those used previously and as such, this report follows the format of the previous reports (Aquilina, 2018 through 2020). Much of the descriptive material is retained from those reports 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. Sample points at all sites were the same as for previous sampling and correspond in some cases to Environment Agency sampling sites. The Drayton sites were visited by Robert Aquilina on Wednesday 5th May 2021 and Manor Farm and Bishops Sutton on Wednesday 19th May 2021, both dates comparable to previous years. The reason for the split visits was to allow sorting to take place on the same and following day as collection in order to optimise specimen recovery as no refrigeration was available. Samples were collected for analysis in the laboratory using standard techniques. The weather conditions were cool and breezy but suitable for the survey with normal water flow levels on both occasions. 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 (TL5) 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 standard BMWP and its more sophisticated modification WHPT. 5
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 live sorted and specimens preserved in 70% IMS for identification. 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.
6
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. New photographs are supplied and any changes in the habitat are 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 50% covered by 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 gravel. Both the marginal vegetation and the Fontinalis moss were markedly reduced from previous years. In the case of the marginal vegetation this is due to the unusually cold spring weather, but this should not have affected the submerged Fontinalis.
7
Photograph 1: Bishop’s Sutton outflow 2021
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.
8
Photograph 2: below Drayton outflow 2021
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. Ranunculus growth occupied approximately half the channel with the remainder being exposed gravel, similar to most previous years. Therefore sampling was equally concentrated in the Ranunculus and the gravel, with some marginal vegetation being sampled. Marginal vegetation was markedly reduced due to the unusually cold spring weather.
9
Photograph 3: above Drayton outflow 2021
The Manor Farm outflow is located at SU 58532 33516. The habitats present consisted of cobbles, small stone, gravel, coarse sand, with almost no in-channel and limited marginal vegetation. All in-channel vegetation has been removed. Therefore sampling was almost exclusively in the gravel with a tiny patch of Ranunculus and some marginal vegetation being sampled.
10
Photograph 4: Manor Farm outflow.
Results
The full species lists are presented as an appendix. Note that the significance of blank counts against species in each site means that that species has been recorded in previous seasons but not this one. The results summarised here consist of number of species, abundance and WHPT, N-taxa and ASPT for current and previous years. These are presented by site as well as by index for comparative purposes. 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.
11
Site
Date
# species Abundance N-taxa WHPT ASPT
Bishop’s Sutton
22.5.2018 28.5.2019 14.5.2020 19.5.2021 Below Drayton Farm 22.5.2018 28.5.2019 6.5.2020 5.5.2021 Above Drayton Farm 22.5.2018 28.5.2019 6.5.2020 5.5.2021 Manor Farm 22.5.2018 28.5.2019 14.5.2020 19.5.2021
49 31 51 38 47 40 52 44 46 39 47 46 53 39 47 53
1237 1478 1660 1182 813 1165 1331 1004 1966 1809 1835 1425 1675 2515 2032 1596
35 27 36 33 34 31 38 32 32 29 37 35 38 34 38 40
194.6 139.3 196.5 166.5 174.8 154.3 204.4 176.1 149.4 146.9 197.2 184.9 204.8 186.5 215.2 228.7
5.56 5.16 5.46 5.05 5.14 4.98 5.38 5.50 4.67 5.07 5.33 5.28 5.39 5.49 5.66 5.72
Table 2. Results summary The results show a mixed picture with Manor Farm showing an increase, above Drayton Farm being almost exactly the same and slight declines (not significant) at Bishops Sutton and below Drayton Farm. Improvements in scores are highlighted in blue and equivalent scores in orange in Table 2. All indices show improvements since 2019. Table 3 gives the means of the reported values in comparison with this years results. Increases in values are highlighted in blue, but the differences between 2021 results and the mean are very small and certainly insignificant. Site Bishop’s Sutton
Date
19.5.2021 mean Below Drayton Farm 5.5.2021 mean Above Drayton Farm 5.5.2021 mean Manor Farm 19.5.2021 mean
# species Abundance N-taxa WHPT ASPT 38 40.0 44 45.3 46 44.0 53 46.3
1182 1440.0 1004 1166.7 1425 1689.7 1596 2047.7
33 32.0 32 33.7 35 33.7 40 37.3
166.5 167.2 176.1 178.1 184.9 176.3 228.7 210.1
5.05 5.2 5.50 5.3 5.28 5.2 5.72 5.6
Table 3. Comparison with three year running mean. 12
Gammarus counts are summarised below but also show an increase at both Drayton sites.
Site
2018 2019 2020 2021
Bishop’s Sutton Below Drayton Above Drayton Manor Farm
323 91 223 638
405 243 115 272
530 386 261 805
286 470 284 293
Table 4. Gammarus counts
WHPT scores 240 220 200 180 160 140
Manor Farm
Above Drayton
Below Drayton
01/05/2021
01/03/2021
01/01/2021
01/11/2020
01/09/2020
01/07/2020
01/05/2020
01/03/2020
01/01/2020
01/11/2019
01/09/2019
01/07/2019
01/05/2019
01/03/2019
01/01/2019
01/11/2018
01/09/2018
01/07/2018
01/05/2018
120
Bishops Sutton
Graph 1. WHPT scores 2018 - 2021
Graph 1 shows the WHPT scores across the four years for which May data has been collected. No significant trend is apparent with the data oscillating around the mean as would be expected in a stable system that was neither in recovery nor decline. The results are consistent with good water quality and high biodiversity, as would be expected in chalk streams showing little impact from the watercress operations. Variations in biodiversity which are reflected in these indices are due to a number of factors which will vary from year to year :-
13
Weather o The particularly cold spring has noticeably affected the marginal vegetation which is considerably reduced. The weather will have little effect on the stream itself as it is fed from a borehole with water at a more or less constant temperature. However significant rainfall events will increase sediment entering the stream which has a negative effect. Stream vegetation management o Manor Farm is cleared of in-channel vegetation by the landowner which would be expected to have a depressing effect on biodiversity as there are less habitats available. This is at odds with the results which may be due to recovery after previous disturbance or just natural variation. Below Drayton Farm, the channel is too shaded for any in-channel vegetation to develop. The other two sites can be expected to undergo annual variations in the amount of vegetation present which is reported each year in the location descriptions. Sampling efficacy o As previously discussed these samples are representative of the community present but vary slightly year on year which will contribute to some of the variation in results.
It is interesting to note that two new species never previously recorded have been found this year. These are a mayfly Paraleptophlebia submarginata at the below Drayton Farm site. This is a large mayfly typically found in stony streams and rivers. The second is the Nationally Scarce moss beetle Ochthebius exsculptus found at both below Drayton Farm and at Manor Farm. This is an unusual record as the beetle is more often found in the north of England and Scotland and has not been recorded in Hampshire before. It is typically found in running water or on the edge of streams.
14
Photograph 5: Ochthebius exsculptus
Conclusions
Clearly water quality is good enough to maintain high biodiversity, other factors being equal. Of course overlaid on this is the year on year natural variation that weather and management bring. Repeated sampling is beginning to show the longer term trend of results cycling around a mean with no significant variation to suggest negative impacts from water quality.
15
References Aquilina, R. (2018). Macroinvertebrate Survey of three watercress farm outflows, Alresford, Hants. Aquilina, R. (2018). Macroinvertebrate Survey of Drayton watercress farm outflow, Alresford, Hants. Aquilina, R. (2019). Macroinvertebrate Survey of watercress farm outflows, Alresford, Hants 2019. Aquilina, R. (2020). Macroinvertebrate Survey of watercress farm outflows, Alresford, Hants 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 abundancerelated scores from field data. River Research and Appications. 30: 887-904.
16
Appendix 1 Species recorded. Group
BMWP family
Species
Common name
Status
Abundance
Bishops Sutton
BMWP
WHPT
19/05/2021
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Dugesiidae
Dugesia polychroa gr.
Flatworm
Tricladida
Planariidae
Polycelis felina
Flatworm
Tricladida
Planariidae
Polycelis nigra
Flatworm
Tricladida
Planariidae
Flatworm
Mollusca
Hydrobiidae
Polycelis tenuis Potamopyrgus antipodarum
Mollusca
Physidae
Physa fontinalis
Bladder snail
Mollusca
Lymnaeidae
Galba truncatula
Dwarf Pond snail
Mollusca
Lymnaeidae
Lymnaea palustris
Marsh 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 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
Jenkins spire snail
=Lymnaea peregra
1
5
3.0
22
5
5.4
1 1
3 3
4.1 2.7
15
3
2.5
19
3
3.0
1 14 2 87 286 33
3 6 3 3 6 3
3.3 5.5 4.4 2.3 4.6 2.0
Group
BMWP family
Species
Common name
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Glossiphonia heteroclita
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 rivulorum
Mayfly
Hemiptera
Gerridae
Gerris sp.
Water skater
Hemiptera
Veliidae
Velia caprai
Water cricket
Hemiptera
Corixidae
Sigara dorsalis
Lesser water boatman
Coleoptera
Haliplidae
Brychius elevatus
Crawling water beetle
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Status
Abundance
3
BMWP
WHPT
3
2.5
50 42 30
10 4
8.5 5.9
3
5
3.6
7 27
5 5
4.5 7.4
17
nymph
larvae not identifiable to species
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Nebrioporus elegans
Diving beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving 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
18
4
Group
BMWP family
Species
Common name
Status
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Diplectrona felix
Caseless caddis
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Polycentropodidae
Plectrocnemia conspersa
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Brachycentridae
Brachycentrus subnubilis
Cased caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Agraylea multipunctata
Cased caddis larvae not identifiable to species larvae not identifiable to species
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
Trichoptera
Leptoceridae
Adicella reducta
Long-horned caddis
Trichoptera
Leptoceridae
Mystacides sp.
Long-horned caddis
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax cingulatus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
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
Ephydridae
Shore fly
pupa
19
Abundance
BMWP
2
WHPT
6.9
6
5
5.8
6
7
8.1
18
7
7.6
18
6
6.5
3 1
10
6.7
9
7
5.9
1 23 25 66
10 10
11.1 9.4 5.5 1.3
early instars not identifiable to species
2
Group
BMWP family
Diptera
Empididae
Diptera
Muscidae
Diptera
Species
Common name
Status
Dance fly
larvae
Stable fly
larvae
Psychodidae
Moth fly
larvae
Diptera
Sciomyzidae
Snail-killing flies
Diptera
Simulidae
Blackflies
larvae early instars not identifiable to species
Diptera
Stratiomyidae
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Limnophora riparia
Simulium sp.
Dicranota sp.
Abundance
N-taxa Total ASPT
20
BMWP
WHPT
50 2
5
6.1 3.6
1 104 182
5
5.4
1
1.4
38 1182
30 153 5.10
33.0 166.5 5.05
Group
BMWP family
Species
Common name
Status
Abundance
BMWP
WHPT
05/05/2021
Above Drayton 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
Stagnicola palustris
Marsh snail
=Lymnaea palustris
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
=Lymnaea peregra
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
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
5 32 2 1 145 1
5 3
5.4 2.7
3
1.2
4
3
3.2
2
3
3.1
13
6
5.5
14
3
2.3
284 75
6 3
4.5 2.0
1
Twisted ramshorn
21
Group
BMWP family
Common name
Glossiphonidae
Species Glossiphonia complanata
Hirudinea Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
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
Plecoptera
Perlodidae
Isoperla grammatica
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
17 212
Leech
22
BMWP
WHPT
3
0.8
1 91 151 32
4 10
5.2 8.5
4
7.2
1
7
6.5
1 2 1
7 10
8.7 10.5
1
5
3.7
11
5
4.8
nymph
larvae not identifiable to species
Group
BMWP family
Species
Common name
Status
Diving beetle
larvae not identifiable to species
Coleoptera
Dytiscidae
Coleoptera
Hydrophilidae
Anacaena limbata
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
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Polycentropodidae
Plectrocnemia conspersa
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
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
Cased caddis
6
Trichoptera
Limnephilidae
Limnephilus lunatus Melampophylax mucoreus
Cased caddis
35
Trichoptera
Limnephilidae
Micropterna lateralis
Cased caddis
23
larvae not identifiable to species larvae not identifiable to species
Abundance
BMWP
WHPT
2
5
5.8
10
5
7.4
6 6 1
5
6.8 5.8
4 24
7 7
8.1 7.6
6 10
6.5 6.7
7
6.9
18 3 4
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
Meniscus midge
larvae
Diptera
Empididae
Dance fly
pupa
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
cranefly
larvae
Diptera
Tipulidae Tipulidae (Limoniidae)
Helius sp.
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
Dicranota sp.
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Nematoda
Nematode worms
Cased caddis
Status
Abundance
BMWP
WHPT
early instars not identifiable to species
9
10
8.9
larvae
Dixa nebulosa
Simulium sp.
24
21 9
5.5 1.2
1
4.5
31 2
5
6.1 3.6
2
5
5.4
58 72 1
1
2.3
Group
BMWP family
Species
Common name
Status
Abundance N-taxa Total ASPT
25
46 1425
BMWP
30 163 5.43
WHPT
35.0 184.9 5.28
Group
BMWP family
Species
Common name
Status
Below Drayton 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
Whirlpool ramshorn
Mollusca
Planorbidae
Anisus vortex Bathyomphalus contortus
Mollusca
Planorbidae
Gyraulus crista
Nautilus ramshorn
Mollusca
Planorbidae
Hippeutis complanata
Flat ramshorn
Mollusca
Planorbidae
Planorbis carinatus
Keeled 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
Hirudinea
Erpobdellidae
Trocheta subviridis
Leech
=Lymnaea peregra
Abundance
BMWP
WHPT
05/05/2021 2 5
3.0
1
5
4.7
4 1 15
3
3.6
1
3
3.0
1
3
3.3
5 1 17
6 3 3
5.8 4.4 2.3
470 11
6 3
4.6 2.0
Twisted ramshorn
26
Group
BMWP family
Species
Common name
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Glossiphonia heteroclita
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
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
Caenidae
Caenis rivulorum
Mayfly
Ephemeroptera
Ephemeridae
Ephemera danica
Greendrake
Ephemeroptera
Heptagenidae
Mayfly
Ephemeroptera
Leptophlebiidae
Heptagenia sulphurea Paraleptophlebia submarginata
Megaloptera
Sialidae
Sialis lutaria
Alderfly
Plecoptera
Leuctridae
Leuctra nigra
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
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
Status
Turkey Brown dun
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
27
Abundance
BMWP
WHPT
29 2 1
3
2.5
114 16
10 4
9.0 5.9
19 3
7 10
6.5 8.3
1 4
10 4
8.8 4.2
1
7
8.7
1
5
3.6
nymph
larvae not identifiable to species
Group
BMWP family
Species
Common name
Status
Coleoptera
Hydrophilidae
Anacaena globulus
Scavenger water beetle
Coleoptera
Hydrophilidae
Helophorus brevipalpis
Scavenger water beetle
Coleoptera
Hydraenidae
Ochthebius exsculptus
Moss beetle
Nationally scarce
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
Trichoptera
Rhyacophilidae
Trichoptera
Glossosomatidae
Abundance
BMWP
1 126 1 1
5 5
8.5 8.3
Caseless caddis
11 1
5 8
7.2 5.8
Rhyacophila dorsalis
Caseless caddis
1
7
8.1
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
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
Halesus radiatus
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Cased caddis
Trichoptera
Limnephilidae
Limnephilus rhombicus Melampophylax mucoreus
Trichoptera
Limnephilidae
Micropterna lateralis
Cased caddis
Cased caddis
28
4 larvae not identifiable to species larvae not identifiable to species
1
3 2
15
7.8 6
6.1
Group
BMWP family
Species
Common name
Trichoptera
Limnephilidae
Potamophylax cingulatus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis Cased caddis
Status
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
Dixidae
Meniscus midge
larvae
Diptera
Empididae
Diptera
Ephydridae
Diptera
Psychodidae
Diptera
Scathophagidae
Diptera
Sciomyzidae
Dixa nebulosa
Pericoma sp.
Shore flies
pupae
Moth fly
larvae
7
6.9
6
10
8.9
2
5.4 1.2
5
5.4
1
2.3
1 2
larvae
Stratiomyidae
Soldier fly
larvae
cranefly
larvae
Diptera
Tipulidae Tipulidae (Limoniidae)
Eleophila sp.
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
Dicranota sp.
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Diptera
2
larvae
Blackflies
Diptera
WHPT
larvae
larvae early instars not identifiable to species
Simulidae
BMWP
10 early instars not identifiable to species
Trichoptera
Diptera
Abundance
Snail-killing flies Simulium sp.(incl. costatum)
29
1 1 4 90
Group
BMWP family
Species
Common name
Status
Abundance N-taxa Total ASPT
30
44 1004
BMWP
30 161 5.37
WHPT
32.0 176.1 5.50
Group
BMWP family
Species
Common name
Status
Abundance
BMWP
WHPT
19/05/2021 4 5 1
Manor Farm 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
=Lymnaea peregra
Mollusca
Lymnaeidae
Stagnicola palustris
Marsh snail
=Lymnaea palustris
Mollusca
Planorbidae
Anisus leucostoma
Button ramshorn
Mollusca
Planorbidae
Whirlpool ramshorn
Mollusca
Planorbidae
Anisus vortex Bathyomphalus contortus
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
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
3.0 2.8
84
5
5.4
2 4
3 3
2.7 3.6
4
3
3.0
6 2 23 5 143 293 43
3 6 3 3 6 3
3.3 5.5 4.4 0.8 4.6 2.0
9 6
3
2.5
Twisted ramshorn
31
Group
BMWP family
Species
Common name
Plecoptera
Nemouridae
Nemoura cinerea
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Plecoptera
Perlodidae
Isoperla grammatica
Stonefly
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Status
Abundance
WHPT
1 7 1
7 10
8.7 10.5
67
10
8.5
4
7.2
7 10 10
6.5 8.3 8.5
104 12 1 326 1 1
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
Hemiptera
Gerridae
Gerris sp.
Water skater
nymph
Hemiptera
Veliidae
Velia caprai
Water cricket
nymph
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
larvae not identifiable to species
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Coleoptera
Hydrophilidae
Helophorus sp.
Diving beetle Scavenger water beetle
females not identifiable to species
Coleoptera
Hydraenidae
Ochthebius exsculptus
Moss beetle
Nationally scarce
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
32
BMWP
1
4.5
1 26 1 2 1
5 5
40
5
8.5 7.4
6.9 7.2
Group
BMWP family
Species
Common name
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
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.
Cased caddis
Trichoptera
Leptoceridae
Adicella reducta
Long-horned caddis
Leptoceridae
Athripsodes aterrimus
Long-horned caddis
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Cased caddis
7
Trichoptera
Limnephilidae
Limnephilus lunatus Melampophylax mucoreus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax cingulatus
Cased caddis
2 1
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
Diptera
Ephydridae
Shore fly
pupa and larva
Diptera
Muscidae
Stable fly
pupa and larva
Cased caddis
Limnophora riparia
33
Status
Abundance
larvae not identifiable to species larvae not identifiable to species larvae not identifiable to species
BMWP
WHPT
6 88 1
7
8.1 7.6
14
6
6.5
2 5 1
10
6.7
7
6.9
10 10 10
8.8 11.1 8.9 5.5 1.3
early instars not identifiable to species
3 5 1 19 41
2
Group
BMWP family
Diptera
Psychodidae
Diptera
Sciomyzidae
Diptera
Simulidae
Diptera
Species Pericoma sp. + Psychoda sp.
Common name
Status
Abundance
Moth fly
larvae
1
Snail-killing flies Blackflies
larvae early instars not identifiable to species
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
Simulium ornatum gr.
N-taxa Total ASPT
34
BMWP
WHPT
4.5
35 3
5
6.1 3.6
2
5
5.4
16 121
1
1.4
33 192 5.82
40.0 228.7 5.72
53 1596
