Macroinvertebrate survey of watercress farm outflows, Alresford, Autumn 2020

Macroinvertebrate Survey of watercress farm outflows, Alresford , Autumn 2020

Report prepared by Robert Aquilina MSc MCIEEM

September 2020

Macroinvertebrate survey of watercress farm outflows, Alresford, Autumn 2020

Robert Aquilina MSc MCIEEM

September 2020

Robert Aquilina MSc MCIEEM is an independent consulting ecologist specialising in protected species and freshwater ecology. He is a Full member of the Institute of Ecology and Environmental Management and abides by their Code of Professional Conduct. For further details see www.cieem.net www.aquilina-environmental.co.uk

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Table of contents Summary .............................................................................................................. 4 Introduction .......................................................................................................... 5 Methods ............................................................................................................... 5 BMWP ............................................................................................................................................. 6 WHPT .............................................................................................................................................. 7 Locations ......................................................................................................................................... 7

Results ................................................................................................................. 11 Discussion ............................................................................................................ 14 References ........................................................................................................... 16 Appendix 1 Species recorded. ............................................................................... 17

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Summary

Macroinvertebrate surveys of outflows from Bishop’s Sutton, above and below Drayton Farm and Manor Farm watercress farms at Alresford, Hampshire were carried out using standard sampling techniques. The purpose was to repeat surveys undertaken in the autumn of 2019 in order to investigate any changes and identify any potential water quality issues.

The species present were typical of a chalk stream, with good diversity and water quality scores. A complete list of species is presented together with abundance and diversity (WHPT) scores. Comparison is made with results from the previous year.

Changes appear to be within normal variation in sampling efficacy and natural seasonal variation.

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Introduction

The purpose of this survey was to repeat the assessments carried out the previous year of the discharges from the watercress beds at Bishop’s Sutton, Drayton and Manor Farm around Alresford and identify any impacts to biodiversity. The protocols followed were identical to those used previously and as such, this report follows the format of the previous report (Aquilina, 2019). Much of the descriptive material is retained from that report in order to facilitate understanding.

Drayton and Manor Farm are situated at the head of small chalk streams and use borehole water to supply the watercress beds which then is discharged into the stream. Bishop’s Sutton is located slightly further down the headwaters of another stream but is also fed by borehole water.

All three unnamed streams join the River Alre either directly (Manor Farm) or via Old Alresford Pond. The River Alre in turn joins the River Itchen, an important chalk stream for salmon and trout fishing and conservation.

Sampling at Drayton Farm was carried out above and below the main site as per previous sampling.

The Drayton sites were visited by Robert Aquilina on Monday 7th September 2020 and Manor Farm and Bishops Sutton on Tuesday 15th September 2020. The reason for the split visits was that the weather was unusually warm and no refrigeration was available to store samples whilst waiting to be sorted as in previous years. Therefore there was concern that samples may deteriorate affecting the results. By splitting the sampling, sorting could take place on the same and following day as collection.

The weather conditions were dry and suitable for the survey with normal water flow levels.

Industry standard survey and extraction techniques for the stream (Environment Agency 2012) were used to assess the species present.

Methods The methodology followed is the standard Environment Agency survey and extraction protocol which results in a species list with abundance data. This forms the basis for calculating a number of indices designed to assess the impacts of various factors (depending on the index selected) but in this case is used to calculate the WHPT index (Walley Hawkes Paisley Trigg - river invertebrate index that is used 5

as the basis for river invertebrate status classification for Water Framework Directive) .

Aquatic macroinvertebrates were collected using a standard size FBA D-frame pond net from the major habitats along the stream (stands of different wetland plants, distinctive substrates, tree roots etc.). All the different habitats present were allocated a proportion of the overall sampling time (3 minutes) and different areas of the same mesohabitat were subsampled to ensure that as great a range as possible was sampled.

Each location was also searched for an additional minute looking for surface dwelling animals such as water skaters and whirligig beetles and inspecting submerged habitats such as logs and larger stones for attached animals.

The samples were preserved in 70% IMS and sorted in the laboratory, where all the invertebrates were extracted. The standard BMWP invertebrate groups were recorded : Tricladida (flatworms), Gastropoda (snails and bivalves), Crustacea (slaters, shrimps and crayfish), Hirudinea (leeches), Megaloptera (alderflies), Plecoptera (stoneflies), Ephemeroptera (mayflies), Odonata (dragonflies and damselflies), Hemiptera (water bugs), Coleoptera (water beetles), Trichoptera (caddisflies) and Diptera (true flies). Voucher specimens were retained in order to check their identity.

Dead mollusc shells, and empty caddis cases were discarded and only whole animals were included in the counts.

BMWP Condition assessment of running waters is based on the BMWP (Biological Monitoring Working Party) score. These BMWP family scores (1-10) are industry standard and reflect the sensitivity of the families to pollution. The higher the family score, the more sensitive to oxygen depletion the family is and therefore their presence indicates a cleaner or less impacted site. The effects of pollution generally are to impose a Biological Oxygen Demand upon the receiving waters and so sensitive families are progressively excluded as the BOD increases.

The score for each family present is totalled to give a site score. Because these site BMWP scores are influenced by sample size (a high score can be achieved through a large number of low scoring families as well as a small number of high scoring families) an Average Score Per Taxa (ASPT) is also calculated from the resulting BMWP scores and allows further interpretation of the results. The higher the ASPT, the greater the proportion of more sensitive families in the sample and therefore the better the site condition.

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WHPT WHPT better reflects the quality of the invertebrate community because it is based on a wider range of taxa (mostly families). In particular, WHPT includes more families of Diptera and some families that were grouped together in BMWP (known as BMWP composite taxa) are considered separately in WHPT. So 106 taxa are included in WHPT as opposed to the 82 in BMWP. Additionally the abundance of each taxa is taken into account through the use of abundance classes, the WHPT score for each taxa present depending on its abundance.

Abundance category Numerical abundance AB1 AB2 AB3 AB4

1-9 10 -99 100 - 999 >1000 Table 1: WHPT abundance classes

Apart from accounting for abundance, the calculation of scores is the same as for BMWP and results in equivalent but more accurate reflection of water quality. The scores derived are WHPT overall score (equivalent to BMWP), N taxa and ASPT.

Locations All locations are as sampled in previous years and are described below with any changes in the habitat noted.

The Bishop’s Sutton outflow is located at SU 60400 32321.

The outflow channel is canalised and subject to fast deep flow. There is a gravel bed with strong Ranunculus growth but the banks are vertical stone with little vegetation. Therefore mesohabitats were limited to gravel, Ranunculus, marginal vegetation and the Fontinalis moss growing downstream of the weir. Sampling was concentrated in the Ranunculus which dominated the site (90% cover) and so little of the gravel was sampled as compared with the previous year.

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Photo 1. Bishops Sutton.

The below Drayton outflow was located at SU 59358 33272.

The sample reach was downstream of a bridge with culverts discharging the water, leading to scour in the channel bed. Substrate in this area was gravel with cobbles but was of limited extent. Further downstream, the substrate was fine and soft underfoot in the majority of the channel with some gravel reaches. Banks were earth but had little marginal vegetation. No in-channel vegetation was present presumably because of the shade from the trees. Sampling was concentrated in the gravel and cobble area for 2 minutes and then upstream of the bridge for 1 minute in gravel.

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Photo 2. Below Drayton Farm The above Drayton outflow was located at SU 59682 33310.

The channel is approximately 1 - 1.5 metres wide and 0.2 – 0.3 metres deep. Water flow is maintained by discharge from the borehole. The habitats present consisted of gravel, coarse and fine sands, Ranunculus beds and marginal Glyceria maxima with small amounts of other marginal plants. This represents the head of the stream as upstream are the watercress beds and borehole supply.

A good balance between Ranunculus growth and gravel (50:50%) was present this year compared to the previous which had been dominated by Ranunculus.

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Photo 3. Above Drayton Farm.

The Manor Farm outflow is located at SU 58532 33516.

The habitats present consisted of cobbles, small stone, gravel, coarse sand, with significant regrowth of marginal vegetation (Watercress and Water Speedwell) after the vegetation clearance to improve flow last year. There was only limited recovery of in-channel Ranunculus.

The tree that had fallen across the stream close to the discharge point had been removed and significant disturbance to the far side of the river had occurred. The riverbed appeared to have been scraped and dumped onto the far bank. Although this did not impact the sampling site, some effects through sediment uplift may have occurred.

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Photo 4. Manor Farm.

Results

The full species lists are presented as an appendix. The results summarised here consist of number of species, abundance and WHPT, N-taxa and ASPT for 2019 and 2020.

The significant measure of water quality is the ASPT score. This is because gross scores such as abundance or WHPT are heavily influenced by sampling bias and would be expected to vary on every occasion to some extent. To overcome such bias the Average Score Per Taxon (ASPT) is calculated which reflects more accurately the water quality with higher scores representing less impact.

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Site

Date

Season

# species

Bishop’s Sutton

3/9/19

Autumn

54

2488

38

201.9

5.31

15/9/20 Autumn

46

3035

32

161.8

5.06

Autumn

41

918

31

160.8

5.19

Autumn

40

1043

34

175.0

5.15

Above 22/8/18 Summer Drayton Farm 3/9/19 Autumn 7/9/20 Autumn

46

1966

32

149.4

4.67

45 43

1242 1772

33 35

165.4 160.8

5.01 4.59

Manor Farm

53 47

2699 4894

38 35

211.6 174.0

5.57 4.97

Below 3/9/19 Drayton Farm 7/9/20

3/9/19 Autumn 15/9/20 Autumn

Abundance Ntaxa

WHPT ASPT

Values showing an increase are highlighted in blue Table 2. Results summary The results show an increase in 7 out of the 16 values. Abundance at all sites was up but the other parameters were mostly comparable. A seasonal mean is the best manner of assessing differences and this is shown below, albeit based only on two data points so far.

Site

Mean N-taxa Mean WHPT Mean ASPT

Bishop’s Sutton Below Drayton Above Drayton Manor Farm

35 32.5 34 36.5

181.85 167.9 163.1 192.8

5.185 5.17 4.80 5.27

Table 3. Seasonal means (autumn)

Differences appear to be within the normal variation in sampling efficiency and natural seasonal fluctuation.

Much of the variation in species richness is contributed by single occurrences of species whereas most of the variation in abundance is due to variation of a small number of species. Gammarus counts are summarised below and show an increase at all sites from the previous year.

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Site

Sept 2019 Sept 2020

Bishop’s Sutton Below Drayton Above Drayton Manor Farm

928 364 159 1341

1606 440 580 3598

Table 4. Gammarus counts

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Discussion It is still early to expect any trends to show up as there are have only been two years consistent sampling undertaken so far and strictly speaking only the same seasons data is comparable. The results suggest an increase in WHPT scores from the first sample occasion (May 2019 or August 2018 for Above Drayton Farm), but with a decline from the intervening samples.

This illustrates the natural variation between seasons and years, rather than any significant decline in water quality. The variation in scores is accounted for by relatively insignificant changes in animals captured. For example 76% of the difference in the scores for Manor Farm, the site which shows the greatest fall between 2019 and 2020, is accounted for by just 4 individual animals (2 dance flies and one each of two caddis species).

WHPT scores 220 210 200 190 180 170 160 150 140 130 120

Manor Farm

Above Drayton

Below Drayton

Bishops Sutton

A change in the relative cover of one of the habitats present can account for the shift to lower scoring families which reduces the WHPT and ASPT scores. For example the increase in the marginal vegetation at Manor Farm allows many less oxygen sensitive species to be included as well as reducing the percentage of the most sensitive species from the gravel.

Gammarus counts have all increased from September 2019 to September 2020, which may be due to the warmer weather of 2020. Indeed the warmer weather will cause an increase in water temperatures which lead to a decrease in dissolved oxygen. Neither of these parameters are monitored in these surveys, so this can only be inferred. However, the effects would be to lower the occurrence of the more sensitive, higher scoring families which is seen in these results.

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Overall it is concluded that two factors are the major influence on these results: Normal variation in sampling efficiency which has been suggested as representing 9 – 12 % between experienced practitioners (Clarke et al., 2002).  Natural year on year variation in abundance and species presence. Weather patterns and weed growth (and management) are likely to be major influences. It is expected that there would be at the very least 10% variation between years.  Together an annual variation of 20-25% seems a reasonable expectation and these results fall well within this.

One curious record is that for a beetle Dactylosternum abdominale which is apparently colonising the UK from Madeira. This terrestrial beetle is associated with organic rubbish and has been found in silage clamps, compost and animal manure so its presence in a chalk stream is difficult to account for, unless it is associated with the works on the far side of the river where some dredged material has been dumped onto the bank by the landowner (not TWC).

Photo 5. Dactylosternum abdominale

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References Aquilina, R. (2019). Macroinvertebrate Survey of watercress farm outflows, Alresford, Hants.

Clarke,R.T., Furse, M.T., Gunn, R.J.M., Winder, J.M. and Wright, J.F. (2002). Sampling variation in macroinvertebrate data and implications for river quality indices.

Freshwater Biology 47, 1735-1751.

Environment Agency. (2012). Freshwater macro-invertebrate sampling in rivers.

Operational instruction 018_08. Environment Agency.

Environment Agency. (2012). Freshwater macro-invertebrate analysis of riverine samples. Operational instruction 024_08. Environment Agency.

Environment Agency. (2014). Walley Hawkes Paisley Trigg (WHPT) index of river invertebrate quality and its use in assesing ecological status. Brief Guide version 5.

Paisley,M.F., Trigg,D.J. and Walley,W.J. (2013). Revision of the Biological Monitoring Working Party (BMWP) score system: derivation of present-only and abundancerelated scores from field data. River Research and Appications. 30: 887-904.

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Appendix 1 Species recorded.

Group

BMWP family

Species

Common name

Dendrocoelidae Dugesiidae Planariidae Planariidae Planariidae Hydrobiidae Physidae Lymnaeidae Lymnaeidae Planorbidae Planorbidae Planorbidae Planorbidae Valvatidae Valvatidae Ancylidae Sphaeridae Asellidae Gammaridae Erpobdellidae Erpobdellidae Glossiphonidae Glossiphonidae Glossiphonidae

Dendrocoelum lacteum Dugesia polychroa gr.

Polycelis felina Polycelis nigra Polycelis tenuis Potamopyrgus antipodarum Physa fontinalis Lymnaea palustris Radix balthica Anisus leucostoma Anisus vortex Bathyomphalus contortus Gyraulus albus Valvata cristata Valvata piscinalis Ancylus fluviatilis Pisidium sp.

Asellus aquaticus Gammarus pulex Erpobdella octoculata Trocheta subviridis Glossiphonia complanata Glossiphonia heteroclita Helobdella stagnalis

Flatworm Flatworm Flatworm Flatworm Flatworm Jenkins spire snail Bladder snail Marsh Pond snail Wandering snail Button ramshorn Whirlpool ramshorn Twisted ramshorn White ramshorn Flat valve snail Common valve snail River limpet Pea mussel Water slater Freshwater shrimp Leech Leech Leech Leech Leech

Status

Abundance

BMWP

WHPT

4 7

5

5.4

7

3

2.7

29 2 5 2

3

2.5

3

3.2

2 23 1 123 1606 48

3 6 3 3 6 3

3.3 5.5 4.4 0.8 3.9 2.0

Bishops Sutton Tricladida Tricladida Tricladida Tricladida Tricladida Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Crustacea Crustacea Hirudinea Hirudinea Hirudinea Hirudinea Hirudinea

=Lymnaea peregra

3 7

Group

BMWP family

Species

Common name

Hirudinea Hirudinea Plecoptera Plecoptera Plecoptera Ephemeroptera Ephemeroptera Ephemeroptera

Glossiphonidae Piscicolidae Nemouridae Leuctridae Leuctridae Ephemerellidae Baetidae Baetidae

Theromyzon tessulatum Piscicola geometra Nemurella picteti Leuctra fusca Leuctra nigra Serratella ignita Baetis rhodani Baetis vernus

Duck leech Fish leech Stonefly Stonefly Stonefly Blue-winged Olive Large Dark Olive Medium Olive

Ephemeroptera Hemiptera Hemiptera Hemiptera Hemiptera Coleoptera Coleoptera

Caenidae Gerridae Veliidae Corixidae Corixidae Haliplidae Haliplidae

Caenis sp.

Gerris sp.

Velia caprai Sigara dorsalis Brychius elevatus Haliplus lineatocollis

Mayfly Water skater Water cricket Lesser water boatman Lesser water boatman Crawling water beetle Crawling water beetle

Coleoptera Coleoptera Coleoptera

Haliplidae Dytiscidae Dytiscidae

Haliplus sp.

Nebrioporus elegans Oreodytes sanmarkii

Crawling water beetle Diving beetle Diving beetle

Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera

Dytiscidae Elmidae Elmidae Elmidae Scirtidae

Elmis aenea Limnius volckmari Riolus subviolaceus Elodes sp.

Diving beetle Riffle beetle Riffle beetle Riffle beetle Marsh beetle

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Status

Abundance

BMWP

WHPT

1 1

3 4

2.5 5.2

32 118 235

10

8.5

4

7.2

2 7 2

5

3.7

20 7 37

5

3.4

2 53 1

5

4.8

5

7.4

early instars not identifiable to species nymph

nymph

larvae not identifiable to species

larvae not identifiable to species larva and adults larvae larva and adults larva

1

6.9

Group

BMWP family

Species

Common name

Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera

Hydropsychidae Hydropsychidae Polycentropodidae Rhyacophilidae Glossosomatidae Brachycentridae Hydroptilidae

Diplectrona felix Hydropsyche siltalai Plectrocnema conspersa Rhyacophila dorsalis Agapetus fuscipes Brachycentrus subnubilis Agraylea multipunctata

Caseless caddis Caseless caddis Caseless caddis Caseless caddis Saddle-case caddis Cased caddis Cased caddis

Trichoptera

Hydroptilidae

Hydroptila sp.

Cased caddis

Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera

Hydroptilidae Leptoceridae Limnephilidae Limnephilidae Limnephilidae Goeridae Odontoceridae Sericostomatidae Ceratopogonidae Chironomidae Ephydridae Empididae Muscidae Psychodidae Sciomyzidae

Oxyethira sp.

Mystacides sp.

Drusus annulatus Limnephilus lunatus

Cased caddis Long-horned caddis Cased caddis Cased caddis Cased caddis Cased caddis Silver sedge Cased caddis Biting midge Non-biting midge Shore fly Dance fly Stable fly Moth fly Snail-killing flies

Diptera Diptera Diptera

Simulidae Stratiomyidae Tipulidae

Simulium sp.

Silo nigricornis Odontocerum albicorne Sericostoma personatum

Limnophora riparia Pericoma sp.

Blackflies Soldier fly cranefly

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Status

larvae not identifiable to species larvae not identifiable to species

Abundance

BMWP

WHPT

2 11 7

7 7

8.2 9.2 7.8

6

6.8

1 4

7 10

5.9 8.8

2 7 14

10

8.9 5.4 1.3

19 366 2

pupa

larvae larvae pupa larvae larvae larvae larvae early instars not identifiable to species larvae larvae

2

1

132 1

4.5

5

5.8 3.6

Group

BMWP family

Species

Common name

Status

Diptera Others Others

Tipulidae(Pediciidae) Hydracarina Oligochaeta

Dicranota sp.

cranefly Water mite True worms

larvae

20

Abundance

BMWP

WHPT

29 49

1

2.3

Group

BMWP family

Species

Common name

Tricladida Tricladida Tricladida Tricladida Tricladida Mollusca Mollusca Mollusca Mollusca Mollusca

Dendrocoelidae Dugesiidae Planariidae Planariidae Planariidae Physidae Lymnaeidae Lymnaeidae Lymnaeidae Planorbidae

Dendrocoelum lacteum Dugesia polychroa gr.

Polycelis felina Polycelis nigra Polycelis tenuis Physa fontinalis Galba truncatula Stagnicola palustris Radix balthica Anisus leucostoma

Mollusca

Planorbidae

Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Mollusca Crustacea Crustacea Hirudinea Hirudinea

Planorbidae Planorbidae Planorbidae Valvatidae Valvatidae Ancylidae Sphaeridae Asellidae Gammaridae Erpobdellidae Erpobdellidae

Hirudinea

Glossiphonidae

Anisus vortex Bathyomphalus contortus Gyraulus crista Hippeutis complanata Valvata cristata Valvata piscinalis Ancylus fluviatilis Pisidium sp.

Asellus aquaticus Gammarus pulex Erpobdella octoculata Trocheta subviridis Glossiphonia complanata

Flatworm Flatworm Flatworm Flatworm Flatworm Bladder snail Dwarf pond snail Marsh snail Wandering snail Button ramshorn Whirlpool ramshorn

Status

Abundance

BMWP

WHPT

Above Drayton

Twisted ramshorn Nautilus ramshorn Flat ramshorn Flat valve snail Valve snail River limpet Pea mussel Water slater Freshwater shrimp Leech Leech Leech

2

=Lymnaea palustris =Lymnaea peregra

1 4 4

5 3

4.7 2.7

93

3

2.5

1

3

3.2

4 9 4 15 580 24

3 3 3 3 6 3

3.3 5.8 4.4 2.3 4.5 2.0

12

21

2.8

Group

BMWP family

Species

Common name

Hirudinea Hirudinea Hirudinea Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Ephemeroptera Plecoptera Plecoptera Megaloptera Hemiptera Hemiptera Hemiptera Coleoptera Coleoptera Coleoptera

Glossiphonidae Glossiphonidae Piscicolidae Ephemerellidae Baetidae Baetidae Baetidae Caenidae Ephemeridae Nemouridae Nemouridae Sialidae Corixidae Gerridae Veliidae Haliplidae Haliplidae Haliplidae

Helobdella stagnalis Theromyzon tessulatum Piscicola geometra Serratella ignita Baetis rhodani Baetis vernus Cloeon dipterum Caenis rivulorum Ephemera danica Nemurella picteti Nemoura cinerea Sialis lutaria Sigara dorsalis Gerris sp.

Velia caprai Brychius elevatus Haliplus lineatocollis Haliplus sibiricus

Leech

Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera Coleoptera

Haliplidae Dytiscidae Dytiscidae Dytiscidae Hydrophilidae Hydrophilidae Elmidae Elmidae Elmidae

Haliplus sp.

Nebrioporus elegans Oreodytes sanmarkii Anacaena limbata Helophorus brevipalpis Elmis aenea Limnius volckmari Riolus subviolaceus

Status

Fish leech Blue-winged Olive Large Dark Olive Medium Olive Pond olive Mayfly Greendrake Stonefly Stonefly Alderfly Lesser water boatman Water skater nymph Water cricket Crawling water beetle Crawling water beetle Crawling water beetle Crawling water beetle larvae not identifiable to species Diving beetle Diving beetle Diving beetle larvae not identifiable to species Scavenger water beetle Scavenger water beetle Riffle beetle larva and adults Riffle beetle larva and adults Riffle beetle larva and adults

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Abundance

BMWP

WHPT

68

3

2.5

7 116 174

10

7.9

4

7.2

2

10

8.3

1

5

3.7

1

5

3.6

32 2 1 1 7

5

4.8

5

5.8

5

5.3

Group

BMWP family

Species

Common name

Status

Coleoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera Trichoptera

Scirtidae Hydropsychidae Psychomyiidae Rhyacophilidae Glossosomatidae Hydroptilidae Hydroptilidae Leptoceridae Limnephilidae Limnephilidae Limnephilidae Limnephilidae

Marsh beetle Caseless caddis Caseless caddis Caseless caddis Saddle-case caddis Cased caddis Cased caddis Long-horned caddis Cased caddis Cased caddis Cased caddis Cased caddis

larva

Trichoptera Trichoptera Trichoptera

Limnephilidae Limnephilidae Limnephilidae

Microcara testacea Hydropsyche siltalai Tinodes waeneri Rhyacophila dorsalis Agapetus fuscipes Hydroptila sp.

Oxyethira sp.

Adicella reducta Anabola nervosa Drusus annulatus Halesus digitatus Limnephilus lunatus Melampophylax mucoreus Micropterna lateralis Potamophylax latipennis

Trichoptera Trichoptera Trichoptera Trichoptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera Diptera

Limnephilidae Goeridae Odontoceridae Sericostomatidae Anthomyzidae Ceratopogonidae Chironomidae Culicidae Dixidae Empididae Ephydridae Muscidae

larvae not identifiable to species larvae not identifiable to species

Cased caddis Cased caddis Cased caddis

Silo nigricornis Odontocerum albicorne Sericostoma personatum

Cased caddis Cased caddis Silver sedge Cased caddis

Dixa nebulosa Clinocera sp.

Setacera sp.

Limnophora riparia

Biting midge Non-biting midge Mosquito Meniscus midge Dance fly Shore fly Stable fly

23

Abundance

BMWP

WHPT

3 1 19 15 31

8 7

5.8 8.1 7.6

6

6.5

23

7

6.9

2

5.5 -0.9

early instars not identifiable to species

larvae larvae larvae larvae larvae larvae larvae larvae

12 263

1

7.0

3

4.0

Group

BMWP family

Species

Common name

Status

Diptera Diptera

Psychodidae Sciomyzidae

Pericoma sp.

Moth fly Snail-killing flies

Diptera Diptera Diptera Diptera Diptera Diptera Others Others

Simulidae Simulium sp.

Stratiomyidae Syrphidae Tipulidae Tipulidae (Limoniidae) Tipulidae(Pediciidae) Dicranota sp.

Hydracarina Oligochaeta

larvae larvae early instars not identifiable to species larvae larvae larvae larvae larvae

Blackflies Soldier fly Hover fly cranefly cranefly cranefly Water mite True worms

24

Abundance

BMWP

11 1 29

3.3 3.4 5

2 17 15 20 141

WHPT

6.1 1.9

5

6.9

1

1.4

Group

BMWP family

Species

Common name

Tricladida

Dendrocoelidae

Dendrocoelum lacteum

Flatworm

Tricladida

Dugesiidae

Dugesia polychroa gr.

Flatworm

Tricladida

Planariidae

Polycelis felina

Flatworm

Tricladida

Planariidae

Polycelis nigra

Flatworm

Tricladida

Planariidae

Polycelis tenuis

Flatworm

Mollusca

Physidae

Physa fontinalis

Bladder snail

Mollusca

Lymnaeidae

Radix balthica

Wandering snail

Mollusca

Planorbidae

Anisus leucostoma

Mollusca

Planorbidae

Mollusca

Planorbidae

Anisus vortex Bathyomphalus contortus

Button ramshorn Whirlpool ramshorn

Mollusca

Planorbidae

Gyraulus crista

Nautilus ramshorn

Mollusca

Planorbidae

Hippeutis complanata

Flat ramshorn

Mollusca

Valvatidae

Valvata cristata

Flat valve snail

Mollusca

Valvatidae

Valvata piscinalis

Valve snail

Mollusca

Ancylidae

Ancylus fluviatilis

River limpet

Mollusca

Sphaeridae

Pisidium sp.

Pea mussel

Crustacea

Asellidae

Asellus aquaticus

Water slater

Crustacea

Niphargidae

Niphargus aquilex

Cave shrimp

Crustacea

Gammaridae

Gammarus pulex

Freshwater shrimp

Hirudinea

Erpobdellidae

Erpobdella octoculata

Leech

Status

Abundance

BMWP

WHPT

7

5

3.0

1 4 1

5 3 3

4.7 2.7 3.6

26

3

3.0

8 10 35

6

5.8

3

3.5

3

2.3

440 22

6 3

4.6 2.0

Below Drayton

=Lymnaea peregra

Twisted ramshorn

25

Group

BMWP family

Species

Common name

Status

Hirudinea

Erpobdellidae

Leech

Hirudinea

Glossiphonidae

Trocheta subviridis Glossiphonia complanata

Hirudinea

Glossiphonidae

Helobdella stagnalis

Leech

Hirudinea

Glossiphonidae

Theromyzon tessulatum

Hirudinea

Piscicolidae

Piscicola geometra

Fish leech

Plecoptera

Leuctridae

Leuctra fusca

Stonefly

Plecoptera

Nemouridae

Nemurella picteti

Stonefly

Ephemeroptera

Ephemerellidae

Serratella ignita

Blue-winged Olive

Ephemeroptera

Baetidae

Baetis rhodani

Large Dark Olive

Ephemeroptera

Baetidae

Baetis vernus

Medium Olive

Ephemeroptera

Caenidae

Caenis rivulorum

Mayfly

Ephemeroptera

Ephemeridae

Ephemera danica

Greendrake

Megaloptera

Sialidae

Sialis lutaria

Odonata

Calopterygidae

Calopteryx virgo

Alderfly Beautiful demoiselle

Hemiptera

Corixidae

Sigara dorsalis

Lesser water boatman

Hemiptera

Gerridae

Gerris sp.

Water skater

Hemiptera

Veliidae

Velia caprai

Water cricket

Coleoptera

Haliplidae

Brychius elevatus

Crawling water beetle

Coleoptera

Haliplidae

Haliplus lineatocollis

Crawling water beetle

Coleoptera

Haliplidae

Haliplus sibiricus

Coleoptera

Haliplidae

Haliplus sp.

Crawling water beetle Crawling water beetle larvae not identifiable to species

Coleoptera

Dytiscidae

Oreodytes sanmarkii

Diving beetle

Leech

26

Abundance

BMWP

WHPT

64

3

2.5

2 1 1 3 4 16

4 10 7 10

5.2 9.3 8.7 7.9

4

5.9

16

4

4.4

2

8

5.9

1 25

5 5

3.4 4.8

nymph

Group

BMWP family

Species

Common name

Status

Abundance

Coleoptera

Dytiscidae

Coleoptera

Hydrophilidae

Anacaena globulus

Scavenger water beetle

Coleoptera

Hydrophilidae

Helophorus brevipalpis

Scavenger water beetle

Coleoptera

Elmidae

Elmis aenea

Riffle beetle

larva and adults

Coleoptera

Elmidae

Limnius volckmari

Riffle beetle

larva and adults

Coleoptera

Elmidae

Riolus subviolaceus

Riffle beetle

larva and adults

Coleoptera

Scirtidae

Microcara testacea

Marsh beetle

larva

Trichoptera

Hydropsychidae

Hydropsyche siltalai

Caseless caddis

Trichoptera

Psychomyiidae

Lype reducta

Caseless caddis

Trichoptera

Rhyacophilidae

Rhyacophila dorsalis

Caseless caddis

Trichoptera

Glossosomatidae

Agapetus fuscipes

Saddle-case caddis

Trichoptera

Hydroptilidae

Hydroptila sp.

Cased caddis

larvae not identifiable to species

Trichoptera

Hydroptilidae

Oxyethira sp.

Cased caddis

larvae not identifiable to species

Trichoptera

Leptoceridae

Adicella reducta

Long-horned caddis

Trichoptera

Beraeidae

Beraeodes minutus

Cased caddis

Trichoptera

Limnephilidae

Anabola nervosa

Cased caddis

Trichoptera

Limnephilidae

Drusus annulatus

Cased caddis

Trichoptera

Limnephilidae

Halesus digitatus

Cased caddis

Trichoptera

Limnephilidae

Cased caddis

Trichoptera

Limnephilidae

Limnephilus lunatus Melampophylax mucoreus

Diving beetle

larvae

1

Trichoptera

Limnephilidae

Micropterna lateralis

Cased caddis

Trichoptera

Limnephilidae

Potamophylax latipennis

Cased caddis

Trichoptera

Limnephilidae

Cased caddis

Cased caddis

27

early instars not identifiable to species

BMWP

WHPT

100 5 1

5

8.3

1 3 1 2

7 7

8.1 7.8

6

6.5

17

10

7.3

7

7

5.9

Group

BMWP family

Species

Common name

Status

Abundance

BMWP

WHPT

Trichoptera

Goeridae

Silo nigricornis

Cased caddis

Trichoptera

Odontoceridae

Odontocerum albicorne

Silver sedge

Trichoptera

Sericostomatidae

Sericostoma personatum

Cased caddis

1

10

8.9

Diptera

Anthomyzidae

Diptera

Ceratopogonidae

Biting midge

larvae

2

5.4 1.3

Diptera

Chironomidae

Non-biting midge

larvae

Diptera

Dixidae

Meniscus midge

larvae

Diptera

Ephydridae

Shore flies

pupae

Diptera

Muscidae

Limnophora riparia

Stable fly

pupae

Diptera

Psychodidae

Pericoma sp.

Moth fly

larvae

2 3

Diptera

Sciomyzidae

Snail-killing flies

Diptera

Simulidae

Blackflies

larvae early instars not identifiable to species

30

5

6.1

Diptera

Stratiomyidae

Soldier fly

larvae

Diptera

Tipulidae

cranefly

larvae

Diptera

Tipulidae (Limoniidae)

cranefly

larvae

Diptera

Tipulidae(Pediciidae)

cranefly

larvae

5

5.4

Others

Hydracarina

Water mite

Others

Oligochaeta

True worms

1 42 71

1

2.3

larvae

Dixa nebulosa

Simulium sp.

Dicranota sp.

28

5 61

4.0 4.5

Group

BMWP family

Species

Common name

Status

Tricladida

Dendrocoelidae

Dendrocoelum lacteum

Flatworm

Tricladida

Dugesiidae

Dugesia polychroa gr.

Flatworm

Tricladida

Planariidae

Polycelis felina

Flatworm

Tricladida

Planariidae

Polycelis nigra gr.

Flatworm

Tricladida

Planariidae

Polycelis tenuis

Flatworm

Mollusca

Physidae

Physa fontinalis

Mollusca

Lymnaeidae

Galba truncatula

Bladder snail Dwarf pond snail

=Lymnaea truncatula

Mollusca

Lymnaeidae

Radix balthica

Wandering snail

=Lymnaea peregra

Mollusca

Lymnaeidae

Stagnicola palustris

=Lymnaea palustris

Mollusca

Planorbidae

Anisus leucostoma

Mollusca

Planorbidae

Anisus vortex

Mollusca

Planorbidae

Bathyomphalus contortus

Marsh snail Button ramshorn Whirlpool ramshorn Twisted ramshorn

Mollusca

Valvatidae

Valvata cristata

Mollusca

Valvatidae

Valvata piscinalis

Flat valve snail Common valve snail

Mollusca

Ancylidae

Acroloxus lacustris

Lake limpet

Mollusca

Ancylidae

Ancylus fluviatilis

River limpet

Mollusca

Sphaeridae

Pisidium sp.

Pea mussel

Abundance

BMWP

WHPT

7

5

3.0

53

5

5.4

2

3

2.7

1 16

3

2.5

1 15

3

3.0

3 1 22 2

3

3.1 3.6 5.5 4.4

Manor Farm

29

17 3

6 3

Group

BMWP family

Species

Common name

Crustacea

Asellidae

Asellus aquaticus

Crustacea

Gammaridae

Gammarus pulex

Water slater Freshwater shrimp

Hirudinea

Erpobdellidae

Erpobdella octoculata

Leech

Hirudinea

Erpobdellidae

Trocheta subviridis

Leech

Hirudinea

Glossiphonidae

Glossiphonia complanata

Leech

Hirudinea

Glossiphonidae

Helobdella stagnalis

Leech

Hirudinea

Glossiphonidae

Theromyzon tessulatum

Hirudinea

Piscicolidae

Piscicola geometra

Fish leech

Plecoptera

Leuctridae

Leuctra fusca

Stonefly

Plecoptera

Nemouridae

Nemurella picteti

Ephemeroptera

Ephemerellidae

Serratella ignita

Stonefly Blue-winged Olive

Ephemeroptera

Baetidae

Baetis rhodani

Large Dark Olive

Ephemeroptera

Baetidae

Baetis vernus

Medium Olive

Ephemeroptera

Caenidae

Caenis luctuosa

Mayfly

Ephemeroptera

Caenidae

Caenis rivulorum

Mayfly

Ephemeroptera

Ephemeridae

Ephemera danica

Greendrake

Ephemeroptera

Heptageniidae

Rithrogena semicolorata

Olive upright

Megaloptera

Sialidae

Sialis lutaria

Alderfly

Hemiptera

Gerridae

Gerris sp.

Water skater

nymph

Hemiptera

Veliidae

Velia caprai

Water cricket

nymph

Hemiptera

Corixidae

Water boatman

nymph

Coleoptera

Haliplidae

Haliplus lineatocollis

Status

Crawling water beetle

30

Abundance

BMWP

WHPT

134

3

0.8

3598 47

6 3

3.9 2.0

3 14 2

3

2.5

4

7

8.7

15

10

8.5

323 36

4

7.2

1

7

6.5

1

4

4.2

1

5

3.7

Group

BMWP family

Species

Common name

Status

Coleoptera

Haliplidae

Haliplus sp.

Crawling water beetle

larvae not identifiable to species

Coleoptera

Dytiscidae

Oreodytes sanmarkii

Diving beetle

Coleoptera

Hydrophilidae

Dactylosternum abdominale

Scavenger water beetle

Coleoptera

Elmidae

Elmis aenea

Riffle beetle

larva and adults

Coleoptera

Elmidae

Limnius volckmari

Riffle beetle

larvae

Coleoptera

Elmidae

Riolus sp.

Riffle beetle

larvae

Coleoptera

Scirtidae

Elodes sp.

Marsh beetle

larva

Trichoptera

Hydropsychidae

Diplectrona felix

Caseless caddis

Trichoptera

Hydropsychidae

Hydropsyche siltalai

Caseless caddis

Trichoptera

Rhyacophilidae

Rhyacophila dorsalis

Trichoptera

Glossosomatidae

Agapetus fuscipes

Caseless caddis Saddle-case caddis

Trichoptera

Hydroptilidae

Agraylea sp.

Cased caddis

Trichoptera

Hydroptilidae

Hydroptila sp.

Cased caddis

Trichoptera

Hydroptilidae

Ithytrichia sp.

Cased caddis

Trichoptera

Hydroptilidae

Oxyethira sp.

Trichoptera

Leptoceridae

Adicella reducta

Cased caddis Long-horned caddis

Trichoptera

Limnephilidae

Limnephilus lunatus

Cased caddis

Trichoptera

Limnephilidae

Melampophylax mucoreus

Cased caddis

Trichoptera

Limnephilidae

Potamophylax latipennis

Cased caddis

Trichoptera

Limnephilidae

Cased caddis

31

Abundance

BMWP

WHPT

1 50 2 1

5

5.8

5

7.4

3

5

5.8

8

7

8.1

174

7.2

larvae not identifiable to species

19

larvae not identifiable to species

90

6

6.8

3 9

7

6.9

Group

BMWP family

Species

Common name

Trichoptera

Goeridae

Silo nigricornis

Cased caddis

Trichoptera

Odontoceridae

Odontocerum albicorne

Silver sedge

Trichoptera

Sericostomatidae

Sericostoma personatum

Cased caddis

Diptera

Ceratopogonidae

larvae

7

Diptera

Chironomidae

larvae

31

Diptera

Dixidae

Dixa sp.

Biting midge Non-biting midge Meniscus midges

larvae

3

7.0

Diptera

Empididae

Dance fly

larvae

Diptera

Ephydridae

Shore fly

pupa and larva

Diptera

Muscidae

Limnophora riparia

Stable fly

pupa and larva

Diptera

Psychodidae

Pericoma sp. + Psychoda sp.

Moth fly

larvae

3 2

4.0 4.5

Diptera

Sciomyzidae

Snail-killing flies

Diptera

Simulidae

Blackflies

larvae early instars not identifiable to species

57

5

6.1

Diptera

Stratiomyidae

Soldier fly

larvae

Diptera

Tipulidae

cranefly

larvae

Diptera

Tipulidae(Pediciidae)

Dicranota sp.

cranefly

larvae

2

5

5.4

Diptera

Tipulidae(Pediciidae)

Pedicia sp.

cranefly

larvae

Others

Hydracarina

Water mite

Others

Oligochaeta

True worms

7 65

1

2.3

Simulium ornatum gr.

32

Status

Abundance

BMWP

WHPT

35

10

8.8

5.4 2

1.3