Macroinvertebrate Survey of watercress farm outflows, Alresford , Hants 2021

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

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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

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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 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.

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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.

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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. 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.

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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.

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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.

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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.

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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.

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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.

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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

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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 :-

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





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.

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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.

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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.

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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

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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