Macroinvertebrate Survey of watercress farm outflows, Alresford , Autumn 2019
Report prepared by Robert Aquilina MSc MCIEEM
October 2019
Macroinvertebrate survey of watercress farm outflows, Alresford, Autumn 2019
Robert Aquilina MSc MCIEEM
October 2019
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 .................................................................................................................. 9 Conclusions .......................................................................................................... 11 References ........................................................................................................... 12 Appendix 1 Species recorded. ............................................................................... 13
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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 spring 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 May 2019 as well as May 2018. 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 earlier in the 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 sites were visited by Robert Aquilina on Tuesday 3rd September 2019 and samples were collected for analysis in the laboratory using standard techniques. The weather conditions were dry and suitable for the survey with normal water flow levels. Industry standard survey and extraction techniques for the stream (Environment Agency 2012) were used to assess the species present. Methods The methodology followed is the standard Environment Agency survey and extraction protocol which results in a species list with abundance data. This forms the basis for calculating a number of indices designed to assess the impacts of various factors (depending on the index selected) but in this case is used to calculate the WHPT index (Walley Hawkes Paisley Trigg - river invertebrate index that is used as the basis for river invertebrate status classification for Water Framework Directive) . Aquatic macroinvertebrates were collected using a standard size FBA D-frame pond net from the major habitats along the stream (stands of different wetland plants, 5
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. The only difference between the method used in 2018 and 2019 was that in 2018, samples were sorted live which allowed flatworms to be identified to species level. In 2019, because the number of samples had increased to four, processing time would have extended beyond the ability to keep the samples fresh and live and so were all preserved immediately. The only effect that this would have, is on the separation of flatworm species which are reported as species groups and consequently give a slight reduction in number of species for 2019. This was the same as for the May 2019 samples. 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 6
proportion of more sensitive families in the sample and therefore the better the site condition.
WHPT WHPT better reflects the quality of the invertebrate community because it is based on a wider range of taxa (mostly families). In particular, WHPT includes more families of Diptera and some families that were grouped together in BMWP (known as BMWP composite taxa) are considered separately in WHPT. So 106 taxa are included in WHPT as opposed to the 82 in BMWP. Additionally the abundance of each taxa is taken into account through the use of abundance classes, the WHPT score for each taxa present depending on its abundance.
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 2018 and May 2019 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 and gravel.
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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.
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. Significant increases in Ranunculus growth had occurred between 2018 and 2019 leaving much less gravel exposed. Therefore sampling was concentrated in the Ranunculus.
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 after the vegetation clearance to improve flow prior to the May 2019 sampling. There was only limited recovery of in-channel Ranunculus. The tree that had fallen across the stream close to the discharge point appears to be surviving and sending up shoots from the main trunk.
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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 2018 and 2019. 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.
Site
Date
Bishop’s Sutton
22/5/18
Below Drayton Farm
Above Drayton Farm
Manor Farm
Season
# species
Abundance Ntaxa
Spring
49
1237
35
194.6
5.56
28/5/19 Spring 3/9/19 Autumn 22/5/18 Spring
31 54 47
1478 2488 813
27 38 34
139.3 201.9 174.8
5.16 5.31 5.14
28/5/19 Spring 3/9/19 Autumn 22/8/18 Summer
40 41 46
1165 918 1966
31 31 32
154.3 160.8 149.4
4.98 5.19 4.67
146.9 165.4 204.8 186.5 211.6
5.07 5.01 5.39 5.49 5.57
28/5/19 Spring 39 1809 29 3/9/19 Autumn 45 1242 33 22/5/18 Spring 53 1675 38 28/5/19 Spring 39 2515 34 3/9/19 Autumn 53 2699 38 Values showing an increase are highlighted in blue
WHPT ASPT
Table 2. Results summary
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The results show an increase in 12 out of the 16 values. However care must be taken in interpreting this as the sampling took place in a different season and strictly speaking only the results of the same season are comparable. Differences appear to be within the normal variation in sampling efficiency and natural seasonal fluctuation. Overall the number of species captured at each site has increased but overall abundance has increased at only half the sites. 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 May 2019 and at three sites from May 2018 numbers. Strictly speaking comparison should only be made between the same season as there will be a natural rhythm to the population size through the year. Site
May 2018* May 2019 Sept 2019
Bishop’s Sutton Below Drayton Above Drayton* Manor Farm Except * August 2018
323 91 223 638
405 243 115 272
928 364 159 1341
Table 3. Gammarus counts
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Conclusions It is too early to expect any trends to show up as there are only three data points collected so far and only two are in comparable seasons. The results suggest an increase in diversity scores and species richness generally but must not be taken too literally because of the difference in season that the samples were collected in. This increase is matched by Gammarus counts but the same proviso applies. The longest run of sampling has occurred at the Manor Farm site where an initial visit in 2016 allows for some exploration of the variation in results over time which is graphed below. This illustrates the natural variation between seasons and years.
Sep-19
Jul-19
May-19
Mar-19
Jan-19
Nov-18
Sep-18
Jul-18
May-18
Mar-18
Jan-18
Nov-17
Sep-17
Jul-17
May-17
Mar-17
Jan-17
215 210 205 200 195 190 185 180 175 170
Nov-16
WHPT
Manor Farm
Date
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. Repeated sampling should begin to build a dataset robust enough to separate the above effects from any longer term trends and would ideally cover spring and autumn seasons, as initiated.
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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. 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
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Planariidae
Polycelis tenuis gr.
Flatworm
Mollusca
Physidae
Physa fontinalis
Bladder 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
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Glossiphonia heteroclita
Leech
Notes
Abundance
BMWP
WHPT
6 169 6 30 7 7 1 1 1 1 69 1 434 928 59 5 2
5 5 3 3
3.0 5.4 2.7 2.5
3
3.0
3 6 3 3 6 3
3.3 5.5 4.4 0.8 4.6 2.0
Bishops Sutton
=Lymnaea peregra
Group
BMWP family
Species
Common name
Hirudinea
Glossiphonidae
Helobdella stagnalis
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
Hemiptera
Corixidae
Sigara dorsalis
Lesser water boatman
Coleoptera
Haliplidae
Brychius elevatus
Crawling water beetle
Notes
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
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Diplectrona felix
Caseless caddis
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Brachycentridae
Brachycentrus subnubilis
Cased caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Agraylea multipunctata
Cased caddis
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Abundance
BMWP
WHPT
45 4 1 1 1 3 12 137 9 2
3 4 7
2.5 5.2 8.7
10 10
9.3 7.9
4 5
7.2 3.7
5
3.4
5
4.8
5
8.3 6.9
5 7 10 7
7.2 9.2 9.6 7.6
13 2 34 135 2 42 1 13 1 14 1 10 1
Group
BMWP family
Species
Common name
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Ceratopogonidae
Biting midge
larvae
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Ephydridae
Shore fly
pupa
Diptera
Empididae
Dance fly
larvae
Diptera
Muscidae
Stable fly
larvae
Diptera
Psychodidae
Moth fly
Diptera
Simulidae
Simulium sp.
Blackflies
larvae early instars not identifiable to species
Diptera
Tipulidae(Pediciidae)
Dicranota sp.
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Limnophora riparia
Notes larvae not identifiable to species larvae not identifiable to species
# taxa Score ASPT
15
Abundance
BMWP
WHPT
58 4 1 6 56 5 5 58 7
6 10 10 2
6.5 8.8 8.9 5.4 1.3 4.4 7.0 2.6 4.5
15 1 3 47
5 5
6.1 5.4
1
2.3
54 2488
32 169 5.28
38.0 201.9 5.31
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Group
BMWP family
Species
Common name
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Planariidae
Polycelis felina
Flatworm
Tricladida
Planariidae
Polycelis tenuis
Flatworm
Mollusca
Lymnaeidae
Radix balthica
Wandering snail
Mollusca
Planorbidae
Anisus vortex
Whirlpool ramshorn
Mollusca
Valvatidae
Valvata cristata
Flat 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
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Ephemeridae
Ephemera danica
Greendrake
Megaloptera
Sialidae
Sialis lutaria
Alderfly
Hemiptera
Veliidae
Velia caprai
Water cricket
Coleoptera
Haliplidae
Brychius elevatus
Crawling water beetle
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Status
Abundance
BMWP
WHPT
Below Drayton
16
=Lymnaea peregra
4 2 4 4 7 1 48 1 24 364 4 33 2 4 9 2 2 1 3 3 5
5
3.0
5 3 3 3 6 3 3 6 3 3
4.7 3.6 3.2 3.3 5.5 4.4 2.3 4.6 3.6 2.5
10
7.9
4 10 4
5.9 8.3 4.2 4.5
Group
BMWP family
Species
Common name
Coleoptera
Haliplidae
Haliplus sibiricus
Crawling water beetle
Status
Haliplidae
Haliplus sp.
Crawling water beetle
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
larva and adults
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larva and adults
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Leptoceridae
Adicella reducta
Long-horned caddis
Trichoptera
Beraeidae
Beraeodes minutus
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Limnephilidae
Melampophylax mucoreus
Cased caddis
Trichoptera
Limnephilidae
Potamophylax latipennis
Cased caddis
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Trichoptera
Sericostomatidae
Sericostoma personatum
Cased caddis
Diptera
Ceratopogonidae
Biting midge
larvae
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
# taxa Score ASPT
17
BMWP
1 larvae not identifiable to species
Coleoptera
Dicranota sp.
Abundance
1 17 177 1 1 1 6 1 16 1 1 3 5 1 5 15 2 13 123 41 918
5 5 5
3.4 4.8 8.3
5 7 7 10 10
5.8 8.1 7.8 6.7 7.3
7 10 10 2 5
5.9 8.8 8.9 5.4 1.3 5.4
1 29 160 5.52
1.4 31.0 160.8 5.19
Group
BMWP family
Species
Common name
Status
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 vortex
Whirlpool ramshorn
Mollusca
Valvatidae
Valvata cristata
Flat valve snail
Mollusca
Valvatidae
Valvata piscinalis
Valve snail
Mollusca
Ancylidae
Ancylus fluviatilis
River limpet
Crustacea
Asellidae
Asellus aquaticus
Water slater
Crustacea
Gammaridae
Gammarus pulex
Freshwater shrimp
Hirudinea
Erpobdellidae
Erpobdella octoculata
Leech
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Piscicolidae
Piscicola geometra
Fish leech
Ephemeroptera
Ephemerellidae
Serratella ignita
Blue-winged Olive
Ephemeroptera
Baetidae
Baetis rhodani
Large Dark Olive
Ephemeroptera
Baetidae
Baetis vernus
Medium Olive
Ephemeroptera
Baetidae
Cloeon dipterum
Pond olive
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Plecoptera
Nemouridae
Nemoura cinerea
Stonefly
Coleoptera
Dytiscidae
Nebrioporus elegans
Diving beetle
Abundance
BMWP
WHPT
Above Drayton
18
4 5 1 124 17 4 6 10 6 159 26 8 47 1 14 51 63 1 1 11 2
5 3
4.7 2.7
3 3
1.2 3.0 3.1
6 3 6 3 3
5.5 4.0 4.5 2.0 2.5
4 10
5.2 8.5
4
7.2
7
10.7
Group
BMWP family
Species
Common name
Coleoptera
Dytiscidae
Oreodytes sanmarkii
Diving beetle
Coleoptera
Dytiscidae
Diving beetle
Coleoptera
Hydrophilidae
Anacaena limbata
Scavenger water beetle
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Status larvae not identifiable to species larva and adults
larvae not identifiable to species larvae not identifiable to species
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
Trichoptera
Limnephilidae
Drusus annulatus
Cased caddis
Trichoptera
Limnephilidae
Limnephilus lunatus
Cased caddis
Trichoptera
Goeridae
Silo nigricornis
Cased caddis
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Culicidae
Mosquito
larvae
Diptera
Dixidae
Dixa nebulosa
Meniscus midge
larvae
Diptera
Empididae
Clinocera sp.
Dance fly
larvae
Diptera
Ephydridae
Setacera sp.
Shore fly
larvae
Diptera
Muscidae
Limnophora riparia
Stable fly
larvae
Diptera
Psychodidae
Pericoma sp.
Moth fly
Diptera
Simulidae
Simulium sp.
Blackflies
larvae early instars not identifiable to species
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Abundance
BMWP
WHPT
49
5
4.8
16 1 9 3 9
5 5 7 7
5.8 5.3 8.1 7.8
56
6
6.8
7
6.9
10 2
8.8 -0.9 2.0 7.0 7.6 4.4 4.0 3.3
5
6.1
76 36 1 1 153 1 3 65 3 7 53 83
Group
BMWP family
Diptera
Species
Common name
Status
Stratiomyidae
Soldier fly
larvae
Diptera
Tipulidae
cranefly
larvae
Diptera
Tipulidae(Pediciidae)
cranefly
larvae
Others
Hydracarina
Water mite
Others
Oligochaeta
True worms
Dicranota sp.
# taxa Score ASPT
20
Abundance
1 9 12 1 33 45 1242
BMWP
WHPT
5
3.6 6.9
1
2.3
25 125 5.00
33.0 165.4 5.01
Group
BMWP family
Species
Common name
Status
Tricladida
Dendrocoelidae
Dendrocoelum lacteum
Flatworm
Tricladida
Planariidae
Polycelis nigra
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
Anisus vortex
Whirlpool ramshorn
Mollusca
Planorbidae
Bathyomphalus contortus
Twisted 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
Hirudinea
Glossiphonidae
Glossiphonia complanata
Leech
Hirudinea
Glossiphonidae
Helobdella stagnalis
Leech
Hirudinea
Glossiphonidae
Theromyzon tessulatum
Duck leech
Plecoptera
Leuctridae
Leuctra fusca
Stonefly
Plecoptera
Nemouridae
Nemurella picteti
Stonefly
Abundance
BMWP
WHPT
Manor Farm
21
1 21 4 17 1 6 14 2 10 2 31 5 85 1341 27 9 1 5 3 19
5 5 3
3.0 5.4 2.7
3
2.5
3
3.0
3 6 3 3 6 3
3.1 5.5 4.4 2.3 3.9 2.0
3 10 7
2.5 9.3 10.7
Group
BMWP family
Species
Common name
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
Coleoptera
Haliplidae
Haliplus lineatocollis
Crawling water beetle
Status
Coleoptera
Haliplidae
Haliplus sp.
Crawling water beetle
larvae not identifiable to species
Coleoptera
Elmidae
Elmis aenea
Riffle beetle
larva and adults
Coleoptera
Elmidae
Limnius volckmari
Riffle beetle
larvae
Coleoptera
Scirtidae
Elodes sp.
Marsh beetle
larva
Trichoptera
Hydropsychidae
Diplectrona felix
Caseless caddis
Trichoptera
Hydropsychidae
Hydropsyche siltalai
Caseless caddis
Trichoptera
Rhyacophilidae
Rhyacophila dorsalis
Caseless caddis
Trichoptera
Glossosomatidae
Agapetus fuscipes
Saddle-case caddis
Trichoptera
Hydroptilidae
Agraylea sp.
Cased caddis
Trichoptera
Hydroptilidae
Hydroptila sp.
Cased caddis
Trichoptera
Hydroptilidae
Oxyethira sp.
Cased caddis
Trichoptera
Leptoceridae
Adicella reducta
Long-horned 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
22
larvae not identifiable to species larvae not identifiable to species
Abundance
BMWP
WHPT
31
10
8.5
333 179 2 1
4 7
7.2 6.5
5
3.4
5
7.4 6.9
5 7
5.8 8.1 7.6
6 10 7 10 10 10
6.8 6.7 5.9 8.8 11.1 8.9
13 55 1 7 2 2 5 24 1 61 90 5 2 7 1 1
Group
BMWP family
Diptera
Species
Common name
Status
Ceratopogonidae
Biting midge
larvae
Diptera
Chironomidae
Non-biting midge
larvae
Diptera
Dixidae
Meniscus midges
larvae
Diptera
Empididae
Dance fly
larvae
Diptera
Muscidae
Stable fly
pupa and larva
Diptera
Psychodidae
Limnophora riparia Pericoma sp. + Psychoda sp.
Moth fly
Diptera
Simulidae
Simulium ornatum gr.
Blackflies
larvae early instars not identifiable to species
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
# taxa Score ASPT
23
Abundance
11 63 23 2 12
BMWP
WHPT
2
28
5.5 1.3 7.0 7.0 2.6 3.0
81 2 7 1 10 32
5
6.1
5
6.9
1
2.3
53 2699
31 172 5.55
38.0 211.6 5.57