Aquatic Macro-invertebrate Sampling
at three sites on the
Lower Duke of Northumberland’s River;
October 13th 2015:
WHPT Analysis and Preliminary Species Audit
Photos © Ilse Steyl
Report V_1.0
Conducted by:
John Dobson BSc MSc MCIEEM FRES
Make Natural Ltd (Ecological Services)
[email protected]
For:
Green Corridor
Final version: 02/02/2016
Aquatic Macro-invertebrate Sampling
at three sites on the
Lower Duke of Northumberland’s River;
October 13th 2015:
WHPT Analysis and Preliminary Species Audit
Report V_1.0
Conducted by:
John Dobson BSc MSc MCIEEM FRES
Make Natural Ltd (Ecological Services)
[email protected]
For:
Green Corridor
CONTENTS
1. EXECUTIVE SUMMARY.................................................................................................................. 1
2. BACKGROUND .............................................................................................................................. 1
3. METHODS ..................................................................................................................................... 2
Table 1. Locations of the selected Sampling Areas on the DNR, 13 October 2015.......................... 2
4. LIMITATIONS OF SURVEY .............................................................................................................. 4
5. RESULTS ........................................................................................................................................ 5
Table 2: WHPT analysis for the three sampling sites. ...................................................................... 5
Table 3: Species Date from the WHPT Survey of the DNR, 13 October 2015 .................................. 6
6. DISCUSSION .................................................................................................................................. 8
Species Accounts .............................................................................................................................. 9
7. RECOMMENDATIONS ................................................................................................................. 12
8. REFERENCES & BIBLIOGRAPHY ................................................................................................... 13
9.1. Appendix 1: Map showing locations of the Sampling Areas ................................................... 15
9.2. Appendix 2: Photographs ........................................................................................................ 16
9.3. Appendix 3: Risk Assessment .................................................................................................. 17
1. EXECUTIVE SUMMARY
Make Natural Ltd. (Ecological Services) sampled aquatic invertebrates from three sites on the
Lower Duke of Northumberland’s River for Green Corridor on 13 October 2015. The aims of the
survey were to monitor the water quality using WHPT in respect of anticipated river corridor
improvement works, and to make a preliminary inventory of the species present.
26 Families/higher taxa were recorded for WHPT analysis, including a number of moderately
high scoring families (indicating moderately high water quality). No highly pollution intolerant
families (which would indicate high water quality) were recorded.
Of the 35 recorded species, none has a statutory conservation status or are nationally scarce or
rare. Two species are highlighted as being Local or Very Local in Greater London.
One designated invasive species (Schedule 9, W&C Act 1981) was recorded.
2. BACKGROUND
Make Natural Ltd. (Ecological Services) was contracted by Green Corridor (Steyning, West
Sussex) to sample, identify and analyse aquatic macro-invertebrates at three locations on the
Lower Duke of Northumberland’s River (DNR) where it runs through the London Boroughs of
Hounslow and Richmond upon Thames. The River is designated as a Site of Borough Importance
for Nature Conservation grade 1 in both boroughs.
The survey was carried out on 13 October 2015 by John Dobson (JRD)(Make Natural Ltd.)
accompanied for survey area selection and for health and safety purposes by Dr. Ilse Steyl (IS)
(Crane Valley Partnership Development Manager, Green Corridor), and for part of the survey by
Gareth Ryman (Biodiversity Officer, London Borough of Hounslow).
Aims of the Survey
1. To sample aquatic macro-invertebrates following standard methodology and to analyse those
samples utilising invertebrate families as indicators of the organic pollutant load and general
degradation occurring at the sampling sites.
2. To identify the sampled aquatic macro-invertebrates to species level.
1
3. METHODS
WHPT
Sampling and data analysis were conducted according to WHPT (Walley, Hawkes, Paisley &
Trigg) methodology (Environment Agency, 2012) (but see Limitations of Survey p. 4).
Note on WHPT: WHPT is the current revision of the superseded BMWP (Biological Monitoring Working
Party) scoring system for assessing organic pollutants and ‘General Degradation’ in watercourses on the
basis of macro-invertebrate sampling (Chadd, 2010). Key differences between WHPT and BMWP are:
i.
In WHPT the score applied to each taxon is based on extensive research and sampling data (The
development of BMWP scores was committee based). The list of scoring taxa is more extensive
than the BMWP list, due both to the inclusion of additional taxa and splitting of some BMWP
species aggregates.
ii.
WHPT scoring utilises abundance data rather than presence/absence as in BMWP. In addition to
providing additional ecological information this refinement meets Water Framework Directive
(WFD) criteria.
Field Procedures
Three survey areas of the DNR were nominated by IS. At each survey areas the sampling area
was selected by JRD on the basis of typicality (Environment Agency, 2012) and safe access, and
these locations are set out in Table 1.
Although not within the WHPT protocol, some contextual data was collected at each sampling
point; these are the watercourse dimensions and flow rate (a floating object timed 3-5x over a
3m stretch). This data and the calculated discharge rates (Q) are included in Table 1.
At each location sampling was performed within a sampling area 10m up- and downstream of
the access point, using a standard (250mm frame, 1mm mesh) sampling net. A timed 3 minutes
was spent kick-sampling working diagonally upstream over the full width of the river. The
sampling time was divided proportionally between the major mesohabitats present, particularly
silt and fine gravel substrates, and emergent and submerged vegetation. An additional 1 minute
was spent sampling mesohabitats which were under-sampled by kick-sampling. These included:
among the roots of emergent vegetation, beneath large stones and the vertical faces of banks.
The net was washed with river water and inspected for carry-over between each of the three
survey areas. Each of the three samples was transferred to a 5l lidded bucket which was
transported off-site on ice in order to minimise predation and degradation within the samples.
Risk Assessment: See Appendix 3, p. 17.
Biosecurity: Nets, footwear and containers were cleaned and treated before and after the
survey with Safe4Pets, which has proven efficacy against Ranavirus and Chytridiomycosis fungus.
Table 1. Locations of the selected Sampling Areas on the DNR, 13 October 2015
Grid Ref
Site 1
downstream
Site 2
Site 3
upstream
Location Name
Width
m
Mean
depth cm
Depth
cm
¼
½
¾
d¼+d½+d¾
3
Flow rate
-1
m.s
TQ 15339 75589
Nr. Riverside Walk
6.4
16
17
15
16
0.563
0.729
TQ 15283 74604
S. of Whitton Dene
3.89
61
60
74
65
0.2147
0.543
TQ 15041 73500
Rosecroft Gardens
6.7
18
20
20
19.33
0.467
0.478
[N.B. The discharge rate for Site 1 appears anomalous, and it may be that the flow rate at the measured 3m stretch was unrepresentative.]
2
Q
Discharge
3 -1
rate m .s
Sample Processing
Sample Sorting
Large material such as stones and vegetation was removed from the samples manually and
washed and examined to extract macro-invertebrates. Each sample was then passed through a
500μ sieve and the retained material examined in detail.
Leeches (Hirudinea) and flatworms (Tricladida) were removed live (to facilitate identification)
and tubed individually. The samples were then dosed with ethyl acetate in order to kill the
remaining invertebrates. The entire samples were then preserved in 70% iso-propyl alcohol (IPA)
and subsequently transferred in small aliquots to white trays for further examination.
Preliminary sorting of macro-invertebrates was carried out using a magnifying headset in
conjunction with supplementary illumination. Specimens were removed from the samples and
tubed in 70% IPA according to Order or Family as appropriate.
Due to the large numbers of Gammaridae present in samples 1 and 3, 50% of the samples were
examined in detail and the results multiplied by 2 (Davy-Bowker, 2015). The preserved samples
of Gammaridae were spread evenly across the surface of a large white tray which had been
marked-up with ruled lines. Gammaridae lying in 50% of the overall area were selected for
subsequent examination. All Gammaridae present in samples 2 were examined.
Identification
Specimens were examined using a Bausch & Lomb (7-60x) stereozoom microscope and, where
higher magnification was required, a Leitz Laborlux 12 binocular microscope. Various
illumination sources were used including an LED ring-light and a Schott fibre optic light source.
Specimens were identified to family and species utilising the appropriate keys (see References &
Bibliography, p. 13).
Leeches (Hirudinea) and flatworms (Tricladida) were identified live (to facilitate identification of
most species) although subsequently killed where dissection was required to resolve critical
taxa.
The remaining preserved specimens were identified to the taxonomic level appropriate to WHPT
and the project brief (see Limitations of Survey, Page 4). The resulting data was added to a
spreadsheet together with the full biological records. The spreadsheet (Lower DNR Invertebrate
species Data 131015 MNP0255.xlxs) is included with this report.
Voucher material preserved in IPA will be retained for one year from the date of the survey.
3
4. LIMITATIONS OF SURVEY
Modifications to protocol.
(i) WHPT analysis requires at least two annual samples, normally taken in spring and autumn
(Environment Agency, 2012). At the DNR in 2015 a single autumn sampling was carried out. The
full WHPT procedure was therefore not completed in 2015 and the results for that year are
therefore not WFD compliant in that respect.
(ii) In the standard methodology (Environment Agency, 2012) thirty seconds of the sampling
period (total 4 minutes) is spent sampling surface-dwelling macro-invertebrates such as whirligig
beetles (Coleoptera, Gyrinidae) and pond skaters (Heteroptera, Gerridae). No examples of
surface-dwelling fauna were observed at any stage and therefore that thirty seconds was utilised
as additional time sampling other habitats which are normally under-sampled by kick-sampling,
such as among the roots of emergent vegetation and the vertical faces of banks.
Interpretation of Data.
A variety of water quality metrics are publicly accessible via the Environment Agency Catchment
Data Explorer (see References and Bibliography p. 13). Data is available from this source for the
River Crane and for the Duke of Northumberland’s River near Heathrow but not for the Lower
DNR, the subject of this survey. In addition, no WHPT or BMWP data is included.
WHPT scores benchmark all rivers against data obtained from the best quality (unmodified and
unpolluted) examples available. In the absence of available HWPT scores from comparable urban
rivers in south-east England, it is not possible at this stage to benchmark the Lower Duke of
Northumberland’s River against other watercourses of its kind.
Identification of Taxa.
Not all taxa are identifiable beyond the level required for WHPT. For example it not currently
possible to identify most fly (Diptera) and beetle (Coleoptera) larvae to species, whilst
identification of other groups such as Pisidium molluscs (Mollusca, Sphaeriidae) and freshwater
mites (Araneae, Acari) requires sub-specialist input. Early instar riverfly larvae may be
identifiable to family but not to species; and damaged specimens of all taxa may also limit the
scope for identification. The number of specimens identified to species is therefore normally
expected to be significantly lower than the number of specimens identified to family.
4
5. RESULTS
WHPT analysis: The WHPT analysis for the three sampling sites is set out in Table 2.
Table 2: WHPT analysis for the three sampling sites. Families are listed in taxonomic order.
Site 1
Order/Higher Taxon
Family
Site 2
Site 3
No.
WHPT
index
value
No.
WHPT
index
value
No.
WHPT
index
value
Tricladida (flatworms)
Planariidae
0
0
2
4.7
0
0
Mollusca (snails, limpets and mussels)
Physidae
2
2.7
0
0
0
0
Bithyniidae
4
3.6
0
0
0
0
Hydrobiidae
0
0
0
0
1
4.1
Lymnaeidae
0
0
2
3.6
0
0
Planorbidae
1
3.2
7
3.2
3
3.2
Sphaeriidae
16
3.5
9
4.4
19
3.5
Oligochaeta (segmented worms)
NA*
5
3.6
3
3.6
14
2.3
Hirudinea (leeches)
Glossiphoniidae
1
3.4
3
3.4
2
3.4
Erpobdellidae
6
3.6
11
2
0
0
Astacidae
0
0
0
0
1
7.9
Asellidae
6
4
19
2.3
1
4
Gammaridae
214
4.6
57
4.5
198
4.6
Baetidae
23
5.9
0
0
54
5.9
Crustacea (crayfish, slaters and shrimps)
Ephemeroptera (mayflies)
Caenidae
1
6.5
0
0
3
6.5
Odonata Zygoptera (damselflies)
Calopterygidae
1
5.9
16
6.2
0
0
Coleoptera (beetles)
Elmidae
1
5.3
0
0
2
5.3
Neuroptera (lacewings - sponge flies)
Sisyridae
0
0
0
0
2
5.7
Trichoptera (caddisflies)
Glossosomatidae
10
7.6
0
0
14
7.6
Hydropsychidae
17
7.2
17
7.2
15
7.2
Limnephilidae
0
0
1
5.9
0
0
Molannidae
0
0
2
6.5
1
6.5
Leptoceridae
1
6.7
0
0
2
6.7
Dixidae
0
0
7
0
0
0
Chironomidae
4
1.2
12
1.3
4
1.2
Stratiomyidae
1
3.6
0
0
0
0
Diptera (true flies)
N-Taxa
18
14
17
WHPT-ASPT
4.56
4.2
5.03
Total WHPT
82.1
58.8
85.6
Abbreviations
N-Taxa: Number of Taxa
ASPT: Average Score per Taxon
WHPT: Walley, Hawkes, Paisley & Trigg scores (Environment Agency, 2012)
* [Note that Oligochaeta (segmented worms) are scored under WHPT as a Subclass (Oligochaeta) rather than as Families.]
5
Species Data: Species records derived from the survey are summarised in Table 3, and appear in full on the
accompanying spreadsheet.
Notes on Table 3
All species were captured by kick-sampling on 13 October 2015 by J. R. Dobson and subsequently identified by J.
R. Dobson. The locations of the sampling areas on the Duke of Northumberland’s River (DNR 1, 2 & 3) appear in
Table 1, p. 2, and in the Map on p. 15.
The column headed “No. identified (No. present)” shows the number of specimens identified to species followed
by, in brackets, the number of specimens belonging to the appropriate higher taxa which were counted.
Specimens which were too immature or damaged were excluded from species identification. Records of ‘Genus
juvenile ident.’ are included only where no species records for the genus are available from the sampling area.
Table 3: Species Date from the WHPT Survey of the DNR, 13 October 2015
Family
Dugesiidae
Planariidae
nd
nd
nd
Erpobdellidae
Erpobdellidae
Glossiphoniidae
Glossiphoniidae
Glossiphoniidae
Glossiphoniidae
Glossiphoniidae
nd
nd
nd
Bithyniidae
Lymnaeidae
Lymnaeidae
Physidae
Planorbidae
Planorbidae
Planorbidae
Planorbidae
Sphaeriidae
Sphaeriidae
Sphaeriidae
Sphaeriidae
Sphaeriidae
Tateidae
Hydrachnidae
Hydrachnidae
6
Species
Vernacular name
Dugesia lugubris
Polycelis tenuis
Nematoda sp.
Nematoda sp.
Nematoda sp.
Erpobdella octoculata
Erpobdella octoculata
Glossiphonia complanata
Glossiphonia complanata
Glossiphoniidae sp. juv. Ident.
Helobdella stagnalis
Theromyzon tessulatum
Oligochaeta spp.
Oligochaeta spp.
Oligochaeta spp.
Bithynia tentaculata
Lymnaea stagnalis
Radix balthica
Physa fontinalis
Ancylus fluviatilis
Planorbarius corneus
Planorbis planorbis/carinatus
Planorbis planorbis/carinatus
Pisidium spp.
Pisidium spp.
Sphaerium corneum
Sphaerium corneum
Sphaerium corneum
Potamopyrgus antipodarum
nd
nd
Flatworm
Flatworm
Roundworm
Roundworm
Roundworm
Leech
Leech
Leech
Leech
Leech
Leech
Leech
Segmented worm
Segmented worm
Segmented worm
Common bithynia
Great pond snail
Wandering snail
Common bladder snail
River limpet
Great ramshorn
Margined/Keeled ramshorn
Margined/Keeled ramshorn
A Pea mussel
A Pea mussel
Horny orb mussel
Horny orb mussel
Horny orb mussel
Jenkins' spire snail
Freshwater Mites
Freshwater Mites
No. identified
(No. present)
1
1
0 (1)
0 (19)
0 (1)
2
5
1
1
1
1
2
0 (5)
0 (3)
0 (14)
4
1
1
1
1
1
6
1
2
1
13
9
14
1
0 (1)
0 (6)
Larva/
Adult
A
A
nd
nd
nd
A
A
A
A
A
A
A
nd
nd
nd
A
A
A
A
A
A
A
A
nd
nd
nd
nd
nd
A
A
A
Location
DNR 2
DNR 2
DNR 1
DNR 2
DNR 3
DNR 1
DNR 2
DNR 2
DNR 3
DNR 1
DNR 3
DNR 2
DNR 1
DNR 2
DNR 3
DNR 1
DNR 2
DNR 2
DNR 1
DNR 2
DNR 2
DNR 2
DNR 3
DNR 1
DNR 3
DNR 1
DNR 2
DNR 3
DNR 3
DNR 1
DNR 2
Table 3: Species Date from the WHPT Survey of the DNR, 13 October 2015 (continued)
Family
Asellidae
Asellidae
Asellidae
Gammaridae
Gammaridae
Gammaridae
Astacidae
Sisyridae
Baetidae
Baetidae
Caenidae
Caenidae
Calopterygidae
Calopterygidae
Glossosomatidae
Glossosomatidae
Hydropsychidae
Hydropsychidae
Hydropsychidae
Hydropsychidae
Leptoceridae
Leptoceridae
Limnephilidae
Molannidae
Molannidae
Elmidae
Elmidae
Elmidae
Chironomidae
Chironomidae
Chironomidae
Chironomidae
Chironomidae
Dixidae
Stratiomyidae
Species
Asellus aquaticus
Asellus aquaticus
Asellus aquaticus
Gammarus pulex
Gammarus pulex
Gammarus pulex
Pacifastacus leniusculus
Sisyra sp.
Baetis rhodani
Baetis rhodani
Caenis horaria
Caenis horaria
Calopteryx sp. juv. ident.
Calopteryx splendens
Agapetus fuscipes
Agapetus fuscipes
Hydropsyche angustipennis
Hydropsyche angustipennis
Hydropsyche angustipennis
Hydropsyche pellucidula
Athripsodes cinereus
Mystacides azurea
Limnephilidae sp. juv. ident.
Molanna angustata
Molanna angustata
Elmis aenea
Elmis aenea
Oulimnius tuberculatus
Subfamily Orthocladinae
Subfamily Chironominae
Subfamily Chironominae
Subfamily Chironominae
Subfamily Orthocladinae
Dixa nebulosa
Pachygaster atra
Vernacular name
Water hoglouse or -slater
Water hoglouse or -slater
Water hoglouse or -slater
A freshwater shrimp
A freshwater shrimp
A freshwater shrimp
Signal Crayfish
A sponge fly
Large Dark Olive
Large Dark Olive
Anglers’ curse
Anglers’ curse
A Demoiselle
Banded demoiselle
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Caddis fly
A Riffle beetle
A Riffle beetle
A Riffle beetle
Non-biting midge
Non-biting midge
Non-biting midge
Non-biting midge
Non-biting midge
A Meniscus midge
A Soldier fly
No. identified
(No. present)
6
6 (19)
1
15 (214)
9 (57)
12 (198)
1
0 (2)
6 (>10)
5 (54)
1
3 (3)
1
8 (16)
4 (10)
1 (14)
8 (>10)
5
6 (15)
3
1
1
0 (1)
2
1
1
1
1
3
4
2
4
2
7
1
Larva/
Adult
A
A
A
A
A
A
A
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
A
A
A
L
L
L
L
L
L
L
Location
DNR 1
DNR 2
DNR 3
DNR 1
DNR 2
DNR 3
DNR 3
DNR 3
DNR 1
DNR 3
DNR 1
DNR 3
DNR 1
DNR 2
DNR 1
DNR 3
DNR 1
DNR 2
DNR 3
DNR 2
DNR 1
DNR 3
DNR 2
DNR 2
DNR 3
DNR 1
DNR 3
DNR 3
DNR 2
DNR 2
DNR 1
DNR 3
DNR 1
DNR 2
DNR 1
7
6. DISCUSSION
WHPT analysis
The current survey comprises sampling from a single day, whereas the WHPT (and BMWP)
protocol requires two annual samples per sampling area, normally performed in spring and
autumn. Caution should therefore be exercised in comparing these WHPT scores with those
from other sites. In addition no conclusions on changes in water quality can be drawn in the
absence of additional chronological samples from the same sampling points.
WHPT scores are designed to monitor a very broad range of organic pollutants, including
historical influences unobtainable from point sampling/chemical analysis. Other impacts such as
particulate and thermal pollution can also lead to fluctuations in the populations of aquatic
invertebrates, and it therefore important to consider the intervening history of the watercourse
when comparing chronological data from a sampling point. The measurement of other factors by
WHPT is referred to as ‘general degradation’.
The WHPT protocol is designed primarily to allow comparisons between samples from the same
site taken on different dates. In the current survey a significant difference is seen between the
scores for sites 1 and 3 (fast-flowing shallow water with negligible submerged or emergent
vegetation and steep banks) and site 2 (slow-flowing deep water with abundant submerged and
emergent vegetation and a graded bank on one margin). These differences are seen in both the
total WHPT scores and the number of taxa (Families) recorded (Table 2). Clearly these
differences do not reflect major differences in water quality (e.g. the scores ‘improve’ between
sites 2 and 1) and are provisionally ascribed to differences in habitats, particularly the four
elements listed above.
A few of the recorded taxa receive relatively high scores under WHPT indicating that they are
moderately intolerant of organic pollutants; these include Glossosomatidae (caddis flies) and
Dixidae (meniscus midges). The low numbers of both Asellus aquaticus (Crustacea, Asellidae)
and larval Chironomidae (Diptera) recorded also tends to support the view that the water quality
is moderately good.
Species Data
Whilst it is often possible to ascribe immature (or early instar larvae) to a Family, identification
to species usually requires examination of late instar larvae or mature specimens in good
condition. For example adult males are required to reliably identify specimens of Gammarus
(Gammaridae).
8
Species Accounts
Tricladida (Flatworms)
Dugesia lugubris (Dugesiidae): A widespread species characteristic of slower flowing or still water where it
secretes itself in silt or beneath rocks; feeding on a range of invertebrates such a Gammarus, Oligochaetes
and Chironomid larvae.
Polycelis tenuis (Planariidae): A widespread species characteristic of slower flowing or still water where it
secretes itself in silt or beneath rocks; feeding on a range of invertebrates such as Oligochaetes and mayfly
larvae.
Nematoda (roundworms): About 70 freshwater species known from the UK. May be free living or internal
parasites of various invertebrates.
Hirudinea (Leeches).
Erpobdella octoculata (Erpobdellidae): A common leech occurring in all kinds of fresh water and feeding
on a range of invertebrates.
Glossiphonia complanata (Glossiphoniidae): A common leech occurring in all kinds of fresh water where it
forages nocturnally, chiefly on molluscs.
Helobdella stagnalis (Glossiphoniidae): A common leech occurring in all kinds of fresh water where it
forages nocturnally on a range of invertebrates.
Theromyzon tessulatum (Glossiphoniidae): A widespread species favouring slow-flowing and still water; it
feeds on the blood of waterfowl.
Oligochaeta (segmented worms): A variety of freshwater species in several Families occur in the UK, some
are similar to earthworms in appearance.
Mollusca (Freshwater snails)
Bithynia tentaculata (Bithyniidae): Common Bithynia. A very common species found in many freshwater
habitats.
Lymnaea stagnalis (Lymnaeidae): Great pond snail. Our largest Lymnaeid; common in in many freshwater
habitats. Often introduced (from pet shops/garden centres).
Radix balthica (Lymnaeidae): Wandering snail. Common in many freshwater habitats, and a rapid
coloniser of created habitats.
Physa fontinalis (Physidae). Common bladder snail. Common on aquatic vegetation in many freshwater
habitats.
Ancylus fluviatilis (Planorbidae). River Limpet. A common mollusc occurring in all kinds of fresh water,
although avoiding faster-flowing waters. Treated separately from other Planorbidae in WHPT scoring.
Planorbis planorbis/carinatus (Planorbidae). Margined/Keeled Ramshorn. It was not found possible to
reliably distinguish these very similar species on the basis of the specimens obtained from sampling sites 2
and 3. The species may be found together and intermediate forms occur. Both are common species of
rivers, ditches and ponds.
Pisidium spp. (Sphaeriidae). Pea mussels. A genus comprising 16 UK species of tiny (typically 1-3mm)
freshwater mussels. Identification requires sub-specialist input and large samples.
Sphaerium corneum (Sphaeriidae). Horny orb mussel. A widespread species in a range of freshwater
habitats, although intolerant of pollution.
Potamopyrgus antipodarum (Tateidae). Jenkins' spire snail. A widespread species found in a range of
th
freshwater habitats, apart from still water. An introduced species first recorded in the mid-19 century
from brackish habitat in Kent; by the 1930’s however it had become widespread in inland water courses.
9
Species Accounts (continued)
Acari - Hydrachnidae (Freshwater Mites). Many UK species; the larvae are parasitic on various
invertebrates.
Crustacea (crayfish, slaters and shrimps)
Asellus aquaticus (Asellidae). Water Hoglouse/Slater. The very common woodlouse-like species. Pollution
tolerant but present in low numbers in the DNR samples (their presence in high numbers may indicate
pollutants and results in a reduction of the WHPT score)
Gammarus pulex (Gammaridae). Identification is based on mature male specimens which were
represented by only a small proportion of the overall samples.
All the counted individuals were however inspected for characters indicative of related and similar
species. In the light of this screening, no Dikerogammarus spp. were recorded. In addition no Crangonyx
pseudogracilis (a Gammarus-like non-native but very widespread freshwater shrimp) were detected.
Although it is considered very likely that C. pseudogracilis occurs in the DNR, it was not recorded on this
occasion.
Pacifastacus leniusculus (Astacidae): Signal Crayfish. One adult male was netted at site 3 and retained as a
preserved specimen.

Designated under Schedule 9 of the Wildlife & Countryside Act (1981).

A UK WFD TAG alien species (Water Framework Directive Technical Advisory Group).

London Invasive Species Initiative (LISI) Listed: Non-native crayfish: category 4: ‘Species which are
widespread for which eradication is not feasible but where avoiding spread to other sites may be
required.’
Neuroptera (lacewings and allies)
nd
Sisyra sp. (Sisyridae). Spongeflies. Neither of the two specimens of 2 instar larvae from sampling site 3
was in sufficiently good condition to ascribe to species. The aquatic larvae feed on freshwater sponges
whilst the small (c.1cm wingspan) adult lacewings are active at dusk (crepuscular), feeding on both
honeydew and invertebrate prey such as aphids.
Ephemeroptera (mayflies)
Baetis rhodani (Baetidae). Large Dark Olive. One of the UK’s commonest mayflies. The larvae favour riffle
habitats and there are two generations per year.
Caenis horaria (Caenidae). Anglers’ curse. A widespread but often rather local mayfly. The larvae inhabit
mud and silt, and the small (c.7mm body length) adults may be active between May and September.
Odonata - Zygoptera (damselflies).
Calopteryx splendens (Calopterygidae). Banded demoiselle. The larvae were found primarily among
submerged vegetation in the slower moving water at sample point 2. 8 of the 16 specimens from that
location were sufficiently mature to ascribe reliably to species. The larvae require slow-flowing rivers with
submerged vegetation, and although generally common in England and Wales this species is rather local in
Greater London, depending on the availability of suitable habitat.
10
Species Accounts (continued)
Trichoptera (caddisflies)
Agapetus fuscipes (Glossosomatidae). Common throughout the country; larvae in stony river beds.
Hydropsyche angustipennis (Hydropsychidae). A common species, primarily in lowland rivers and streams.
Hydropsyche pellucidula (Hydropsychidae). A common species of streams and rivers.
Athripsodes cinereus (Leptoceridae). A common species of streams, rivers and lakes.
Mystacides azurea (Leptoceridae). A common species of streams, rivers, ponds and lakes.
Molanna angustata (Molannidae). A common species of ponds, lakes, canals and slow rivers. The
specimen from fast-flowing water (DNR sampling point 3 - upstream) is an apparent anomaly which might
represent downstream drift from a slow-flowing stretch upstream?
Coleoptera (beetles)
Elmis aenea (Elmidae). A Riffle beetle. A common species of running water where it clings to submerged
stones and riverside vegetation.
Oulimnius tuberculatus (Elmidae). A Riffle beetle. A local species of running water where it appears to
show a preference for submerged exposed root systems.
Diptera (flies)
Chironomidae. Non-biting midges. A large family of flies with well over 600 species recorded from the
British Isles. Pollution tolerant but present in low numbers in the DNR samples (their presence in high
numbers may indicate pollutants and results in a reduction of the WHPT score).
Dixa nebulosa (Dixidae). A Meniscus midge. The most frequently encountered member of the Genus in
lowland England, although records for SE England are rather sparse (NBN Gateway - see References). The
surface-dwelling (meniscus) larvae are found among stands of emergent vegetation.
Pachygaster atra (Stratiomyidae). A Soldier fly. The larva of this common species is not generally
considered to be aquatic, and the species does not of course belong in this analysis if the solitary larva
netted at sampling point 1 had simply fallen into the water. However there are records of larvae from wet
decaying vegetation (Stubbs, 2001) so it might be associated in this instance with marginal semi-aquatic
habitat.
11
Species Designations
No species with conservation designations were recorded in the course of the survey. These
designations include: Protected by Statute, Red Data Book, Nationally Scarce, S41 (species of
principal importance for the conservation of biodiversity in England), Greater London BAP species
or species prioritised in the Biodiversity Action Plans for Hounslow or Richmond upon Thames.
The Signal Crayfish Pacifastacus leniusculus (Astacidae) is an invasive species as designated
under Schedule 9 of the WCA (1981); by the Water Framework Directive Technical Advisory
Group (WFD TAG) and in the London Invasive Species Initiative (LISI) List.
Conservation-worthy Species: 1.
Although both may be common and widespread elsewhere in the country, in the surveyor’s
opinion (and in the absence of specific published evidence) the following two species should be
considered as Local or Very Local in Greater London, and therefore legitimate targets for habitatbased conservation measures.
Oulimnius tuberculatus (Elmidae). A Riffle beetle. Key habitat requirements include riffles and
particularly submerged root tangles.
Calopteryx splendens (Calopterygidae). Banded Demoiselle. Key habitat requirements include slower
moving deeper water with abundant submerged vegetation.
Acquainting volunteers and contractors with these species and their habitats would tend to
decrease the risk that key habitats are disrupted in the course of other works.
Conservation-worthy Species: 2.
The following species which were recorded at sampling point 2 each have a specific requirement
for slow-moving water.
Dugesia lugubris
Polycelis tenuis
Theromyzon tessulatum
Ancylus fluviatilis
Calopteryx splendens
Molanna angustata
Flatworm
Flatworm
Leech
River Limpet
Banded Demoiselle
Caddis fly
Bearing in mind that these records are the result of sampling for monitoring rather than (more
thorough) ecological survey, they provide preliminary evidence for the presence of a community
of invertebrates in the DNR associated with slow-flowing water, and thus emphasise the value of
these areas alongside the faster flowing stretches.
7. RECOMMENDATIONS



In carrying out improvement works to the DNR, avoid as far as practicable disrupting the
habitats associated with the ‘conservation-worthy’ species detailed above.
No WHPT data for comparative purposes is available at this time from urban rivers in SE
England via the Environment Agency Data Explorer (see References and Bibliography). It
would clearly be of some interest to be able to benchmark the DNR WHPT and derived scores
against those obtained from similar urban rivers in the region. In that case it would be
worthwhile to obtain such figures from other sources, if practicable.
In planning further survey of aquatic invertebrates, in addition to repeat WHPT survey,
consider ecological survey sampling if it is thought desirable to gain a clearer understanding
of the invertebrate species complement of the DNR.
12
8. REFERENCES & BIBLIOGRAPHY
[To activate links add a colon after http or https; e.g. http// to http://]
Nomenclature of taxa follows the Natural History Museum UK Species Inventory, which
provides authorities:
http//www.nhm.ac.uk/research-curation/scientific-resources/biodiversity/uk-biodiversity/ukspecies/index.html
Bryce, D. & Hobart, A. (1972). The Biology and Identification of the Larvae of the Chironomidae
(Diptera). Entomologist's Gazette 23; 175-217.
Buglife/Environment Agency (2015). Crayfish Identification, Distribution and Legislation.
https//ww.buglife.org.uk/sites/default/files/Final%20Crayfish%20ID%20distribution%20
and%20Legislation%2023%2006%2015_JG.pdf
Chadd, R. (2010). Assessment of Aquatic Invertebrates. In: Hurford, C., Schneider, M. & Cowx, I.
(eds.). Conservation Monitoring in Freshwater Habitats: A Practical Guide and Case
Studies. Springer.
Cham, S. (2009). Field Guide to the larvae and exuviae of British Dragonflies; Volume 2:
Damselflies. The British Dragonfly Society, Peterborough
Constable, D. (2014). Notes on the importance of sexing Gammaridae for identification: using
Dikerogammarus as an example. V1. Environment Agency.
https//www.fba.org.uk/downloads
Davy-Bowker, J. (2015). RIVPACS/RICT Bioassessment Training Manual. Freshwater Biological
Association, Wareham. Unpublished.
Denton, J. (2007). Water Bugs and Water Beetles of Surrey. Surrey Wildlife Trust, Pirbright.
Disney, R. H. L. (1999). British Dixidae (Meniscus Midges) and Thaumaleidae (Trickle Midges):
Keys with Ecological Notes. Freshwater Biological Association Scientific Publication No.
56.
Dobson, M. (2013). Family-level keys to freshwater fly (Diptera) larvae. Freshwater Reviews 6 (1).
The Freshwater Biological Association.
Dobson, M. (2013). Identifying Invasive Freshwater Shrimps and Isopods. Freshwater Biological
Association. Revised Edition, May 2013. https//www.fba.org.uk/downloads.
Dobson, M., Pawley, S., Fletcher, M. & Powell, A. (2012). Guide to Freshwater Invertebrates.
Freshwater Biological Association Scientific Publication No. 68.
Edington, J. M. & Hildrew, A. G. (1995). A Revised Key to the Caseless Caddis Larvae of the British
Isles: with Notes on their Ecology. Freshwater Biological Association Scientific Publication
No. 53.
Elliot, J M. (2009). Freshwater Megaloptera and Neuroptera of Britain and Ireland: Keys to the
Adults and Larvae, and a Review of their Ecology. Freshwater Biological Association
Scientific Publication No. 65. (2012 reprint including minor corrections).
Elliot, J. M. and Dobson, M. (2015). Freshwater Leeches of Britain and Ireland: Keys to the
Hirudinea and a Review of their Ecology. Freshwater Biological Association Scientific
Publication No. 69.
13
Elliot, J. M. & Humpesch, U. H. (2010). Mayfly larvae (Ephemeroptera) of Britain and Ireland:
Keys and a Review of their Ecology. Freshwater Biological Association Scientific
Publication No. 66. (2012 reprint including minor corrections).
Environment Agency (2012). Freshwater macro-invertebrate sampling in rivers. Operational
instruction 018_08. (Unpublished procedures manual).
Environment Agency Catchment Data Explorer. http//environment.data.gov.uk/catchmentplanning/
Gledhill, T., Sutcliffe, D. W. and Williams, W. D. (1993). British Freshwater Crustacea
Malacostraca: a Key with Ecological Notes. Freshwater Biological Association Scientific
Publication No. 52.
Holdich, D. M. (2009). Identifying crayfish in British waters. In: Brickland J., Holdich D. M. and
Imhoff, E. M. (eds.) (2009). Crayfish Conservation in the British Isles. Conference
Proceedings; 25th March 2009, Leeds, UK.
Holland, D. G. (1972). A Key to the Larvae, Pupae and Adults of the British Species of Elminthidae.
Freshwater Biological Association Scientific Publication No. 26.
Hounslow Biodiversity Action Plan Partnership. Hounslow Biodiversity Action Plan 2011 - 2016.
http//www.hounslow.gov.uk/biodiversity_action_plan
Kerney, M. (1999). Atlas of the Land and Freshwater Molluscs of the British Isles. Harley Books,
Colchester.
Killeen, I., Aldridge, D., and Oliver, G. (2004). Freshwater Bivalves of Britain and Ireland. Field
Studies Council, Shrewsbury: Occasional Publication 82.
Killeen, I. (1992). The Land and Freshwater Molluscs of Suffolk: An Atlas and History. The Suffolk
Naturalists’ Society, Ipswich.
London Invasive Species Initiative. http//www.lbp.org.uk/LISI.html
Macan, T. T. (1977). A Key to the British Fresh- and Brackish-water Gastropods, with notes on
their ecology. Freshwater Biological Association Scientific Publication No. 13.
NBN Gateway: https//data.nbn.org.uk/
Nilsson, A. N. (ed.) (1996). Aquatic Insects of North Europe: A Taxonomic Handbook. Volume 1:
Ephemeroptera, Plecoptera, Heteroptera, Megaloptera, Neuroptera, Coleoptera,
Trichoptera and Lepidoptera. Apollo Books, Stenstrup.
Nilsson, A. N. (ed.) (1997). Aquatic Insects of North Europe: A Taxonomic Handbook. Volume 2.
Odonata - Diptera. Apollo Books, Stenstrup.
Reynoldson, T. B. and Young, J. O. (2000). A Key to the Freshwater Triclads of Britain and Ireland.
Freshwater Biological Association Scientific Publication No. 58.
Richmond Biodiversity Group (2006). Biodiversity Action Plan: London Borough of Richmond
upon Thames. http//www.richmond.gov.uk/richmonds_biodiversity_action_plan
Stubbs, A. and Drake, M. (2001). British Soldierflies and their Allies. British Entomological and
Natural History Society.
Wallace, I. D., Wallace, B. & Philipson, G. N. (2003). Keys to the Case-bearing Caddis Larvae of
Britain and Ireland. Freshwater Biological Association Scientific Publication No. 61.
Wallace, I. D. (1991). A Review of the Trichoptera of Great Britain. Research and Survey in Nature
Conservation No. 32. Nature Conservancy Council, Peterborough.
14
9.1. Appendix 1: Map showing locations of the Sampling Areas
Grid References are given in Table 1 p2.
15
9.2. Appendix 2: Photographs
All photographs appearing in this report © Ilse Steyl
Photo 1: Sampling Site 1 (downstream sample)
Photo 2: Sampling Site 2. Note the deeper water and
submerged vegetation.
Photo 3: Sampling Site 3 (upstream sample)
Photo 4. Signal Crayfish (Pacifastacus leniusculus) from
Sampling Site 3. This male had lost its left fore-limb
(cheliped) and a new limb is in the process of
regenerating. Currently in coll. J.R.Dobson.
Photo 5: Sampling at Site 3
Photo 6: Sampling at Site 2
16
9.3. Appendix 3: Risk Assessment
Risk Assessment
Make Natural Ltd. (Ecological Services)
Risk Ranking: Likelihood x Severity = Risk (High, Medium, Low)
Severity
Likelihood
Low
Medium
High
Low
Low
Low
Medium
Medium
Low
Medium
Medium
Medium
Medium
High
High
Project: Invertebrate sampling of DN River; WHPT and preliminary species audit.
Activity: Kick Sampling for WHPT
RA carried out by: John Dobson (Director)
Other personnel: Ilse Steyl (Green Corridor). Gareth Ryman (Hounslow Council)
Project Ref: MNP0255
Site:
Activity
Date: 13 October 2015
Lower Duke of Northumberland’s River (DNR) in Hounslow and Richmond upon Thames
Hazard
Who’s at risk
Controls in place
Risk
Further controls
required
Residual
Risk
Fieldwork
Lone working
na
n/a: Surveyor
accompanied throughout
by experienced field
worker(s), all with mobile
phones.
na
na
na
Fieldwork
Minor
scratches,
stings, bruises
All
All are experienced field
workers. First-aid kit
carried.
L
na
na
Water
sampling
Trip hazards,
broken glass
etc. in river
Surveyor
Ongoing surveillance by
surveyor and from bank.
Water not turbid and
river bed visible.
L
na
na
Water
sampling
Waterborne
infections
Surveyor
Surveyor free of open
cuts or scratches.
Antiseptic hand ointment
applied regularly.
L
na
na
17
18