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OULTON MARSHES – AN AQUATIC INVERTEBRATE SURVEY OF THE TURF PONDS AND DYKES ADRIAN CHALKLEY Four turf ponds were excavated in 2011 at the Suffolk Wildlife Trust Reserve, Oulton Marshes and six more in 2013 (Plates 8 & 9). These ten ponds were among 21 areas of the reserve surveyed between August 2013 and September 2014. The methodology followed that in the ISIS handbook produced by Natural England. In total 908 records were made comprising 174 distinct invertebrates, belonging to 19 orders. 34 of these were only found within the turf ponds. Five species were new county records. The results were analysed and compared to the same analysis carried out on an earlier survey from 2008. Water quality for the 5 sites in the earlier survey ranged from poor to good whereas the 21 sites from the current survey ranged from good to excellent. The invertebrate communities at each site were classified using the Environment Agency CCI metric. At the time of the 2008 survey all sites were of moderate conservation value. All 21 sites in this survey exceeded moderate and 8 were rated as of very high conservation value which equates to the rating an SSSI should achieve. Comparing species lists from each site showed that: Constructing the turf ponds has increased the range of distinct habitat types available to aquatic invertebrates within the reserve. The biodiversity of the aquatic invertebrate community has increased since the site was bought. The turf pond invertebrates did not mirror the general dyke community, they exhibited a more diverse range of species. The invertebrate communities in the turf ponds were formed only partly by dispersal from dykes across the site, they also came from outside the reserve. In the centre of the reserve are two old ponds whose invertebrate communities were found to be similar to that of the dykes but had little in common with those in the turf ponds. Ongoing management at Oulton, of which turf pond construction is part, has considerably increased the conservation value of the overall invertebrate community since the reserve was acquired. Introduction When the Suffolk Wildlife Trust purchased Oulton Marshes in 2008 an initial survey of the dykes and ditches was carried out by Derek Howlett and Roy Baker of the Wheatfen Partnership. After a programme of dyke dredging and re-profiling during 2009-2010 a repeat survey was carried out. The report on these surveys showed that biodiversity in the invertebrate fauna had increased and predicted that with sympathetic management it should continue to increase further. Meanwhile results from long term monitoring of turf ponds created, or re-created, by the Broads Authority since 1983 indicated that these shallow peat diggings could still be a good method of providing a richly improved, diverse fen vegetation once
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they were left to recolonise. Turf ponds dug in Victorian times tended to be the most species rich areas in the Broads. Oulton Marshes has a history of turf pond digging and in 2011 the SWT obtained a grant from the Million Ponds Project to create four turf ponds with Rists Marsh chosen as the location. Monitoring of the earlier Broads Authority ponds had only been concerned with surveying vegetation and so in September 2012, when the Oulton turf ponds were a year old, I was invited by Dorothy Casey to take a brief look at the initial colonisation by aquatic invertebrates. The results of this visit were set out in a short report and indicated that the turf ponds had already been colonised by an invertebrate community of high taxon richness. Therefore in 2013 the survey reported here was commissioned by the SWT with funding from The SITA Trust. This also enabled the digging of six more turf ponds, two again in Rists Marsh and four others in nearby compartments (see map opposite). This survey was carried out over two years which enabled a series of dykes to be monitored in addition to allowing the new turf ponds a year to mature somewhat before surveying. On the advice of Matt Gooch, the Broads Warden, two existing ponds in one of the reserve compartments, Coopers Marsh, were added to the survey list. These two ponds were a kilometre north of the turf ponds and across the railway line which divides the reserve. Survey Aims and Objectives The primary objective of this survey was to investigate the overall aquatic invertebrate community within the freshwater habitats of Oulton Marshes Reserve using standardised sampling methods. It also aimed to look towards addressing the following questions: Did the construction of turf ponds increase the range of distinct habitat types available to aquatic invertebrates within the reserve? Has the biodiversity of the aquatic invertebrate community increased since the Wheatfen Partnership survey in 2010? With regard to survey results obtained from the turf ponds and the dykes; do turf pond communities simply mirror the general dyke community or do they exhibit a more diverse range of species? Where are the turf pond invertebrate communities recruited from? Is it by dispersal from the nearest dykes, from across the site in general or from outside the reserve? Is there a similarity between the new turf pond communities and that of the two pre-existing ponds? How has ongoing management at Oulton altered the conservation value of that community since acquiring the reserve? Survey and Site Details The twenty one sites sampled comprised the ten turf ponds described above, two older ponds in the middle of the reserve and nine sections of drainage dykes. Work occurred at intervals between August 2013 and September 2014. Sampling was carried out according to the methodology detailed in section 3 of this report on days
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Map: Site location and analysis results from the twenty one sample sites
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chosen to be dry but not necessarily warm or sunny; surveying being targeted at aquatic life stages of invertebrates rather than on flying adults. The relative locations of all sites are shown on the reserve map which includes the earlier Wheatfen Partnership sites mentioned above. A variety of physical parameters were recorded for each of the sites shown above, including pH and Conductivity as recommended in the Broads Authority Turf pond report 2010. The measurements are set out in the table below, followed by a discussion of these data. Table 1. Water Characteristics Site Date
TP 1 30-09 2013 9.4
TP 2 30-09 2013 9.1
TP 3 30-09 2013 9.0
TP 4 30-09 2013 8.9
TP 5 12-09 2014 8.8
TP 6 12-09 2014 8.6
TP 7 12-09 2014 8.7
TP 8 TP 9 TP 10 19-09 19-09 19-09 2014 2014 2014 9.2 9.4 9.3
pH Conductivity 939 749 1460 1120 980 974 926 1100 1270 ÂľS / m (25oC) Temperature oC 13.7 16.7 15.5 17 18.6 17.6 16.5 22 21.6 TDS (Total Dissolved 421 335 660 514 426 432 426 524 572 Solids) mg/L Site Date pH Conductivity ÂľS / m (25oC)
989 20.2 448
P 1 P 2 D 13 D 14 D 15 D 16 D 17 D 18 D 19 D 20 D 21 12-08 12-08 29-08 29-08 29-08 29-08 20-09 20-09 12-08 12-08 19-09 2014 2014 2013 2013 2013 2013 2013 2013 2014 2014 2014 8.9
8.5
8.4
2720 2540 1060
8.8
9.1
8.4
8.1
8.2
8.3
8.4
9.2
747 700 848 856 931 1010 1060 1010
Temperature oC 18.7 19.1
18.3
19.7 22.7 23.1 13.8 14.9 16.3 18.3 24.1
TDS (Total Dissolved Solids) mg/L
484
336 318 364 394 419 453
1241 1160
484
461
Discussion of the physical measurements in table 1 Measurements at each site with a freshly calibrated digital meter showed the water to be base rich with pH values ranging between 8.1 and 9.4. The majority of sites I survey range from 7.0 to 9.0 pH, so seven of the sites exhibited higher than normal values, which are towards the alkaline. It will be seen from the table above and from map 1 that the sites with higher pH were all at the Southern end of Oulton Marshes. Interestingly pH values were given for 4 of the sites in the 2010 Wheatfen survey and these varied between 6.0 and 6.88. This showed the water to be much more acidic than it is today, a change possibly caused after dredging and clearing the dykes but perhaps in part due to other factors in the intervening years.
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The conductivity readings in the table above are, in the main, relatively consistent across the reserve although at the higher end of normal. Freshwaters can often range up to 1200 ÂľS / m and the proximity of tidal waters doubtless has a part to play. However two of the sample sites, namely ponds 1 and 2, both in the centre of the reserve, show conductivity levels over twice those of surrounding areas. Conductivity values given in the Wheatfen survey report were broadly similar to those given above for three sites being 1350, 1371 and 1400 ÂľS, though site W1 was much lower at 336 ÂľS. Freshwater Plants, Invertebrates and Fish can all be affected to different extents by the dissolved solids within the water body. The effects may vary from the inhibition of growth or egg hatching, through to outright mortality. Since these effects vary, not only with species but also with life stage, a maximum level for TDS at which ecological concern may be raised is difficult to specify. However Duffy & Weber-Scannell, (2007) suggest that levels up to 1000 mg/L have little impact on the majority of invertebrates, whereas those above 1000 mg/L are likely to have an increasingly detrimental effect. The table above shows that only two sites, the existing ponds P1 and P2 which have a TDS level exceeding 1000 mg/L. Ponds 1 and 2 therefore gave atypical results with the values for both the conductivity and the total dissolved solids being substantially higher than the other sites. The pH values were however within the normal range across the site. Initially meter errors were suspected but readings taken earlier the same day were consistent with other sample sites and test solutions measured that evening gave the correct result on both meters. The reason for these high values is not obvious and unfortunately the previous history of these ponds throws little light on the subject. The origin of the two ponds is somewhat lost in time. Information from Matt Gooch is that they were in existence long before the reserve was acquired by the Trust and that local people refer to them as bomb craters from the Second World War. However they clearly appear too shallow at present when compared to bomb crater ponds seen elsewhere. The ponds were cleaned out in 2011, although apparently no further indication of their history was found. If they are bomb craters they may have been infilled at some point in the past or possibly, if the rumour referred to unexploded bombs could that have caused shallower ponds? Could the conductivity and perhaps the total dissolved solids have been changed by whatever caused the ponds or lies beneath the soil? All this is very much conjecture and will remain a mystery. In any case, as will be seen from the analysis results in section 6, the invertebrate community of these ponds remains very similar to some other sites on the reserve. Methodology Field Methods The methodology chosen was that specified for still waters by Natural England in their ISIS survey tool. Still-water faunas are usually dominated by adult beetles, bugs and molluscs, for which this method produces high yields. It was felt that this
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methodology would be not only the most appropriate for the site but will be easily repeatable for future surveys. It can also be used by the Suffolk Wildlife Trust to compare these results with those obtained from previous surveys from other sites such as Redgrave and Lopham Fen or The Hen Reedbeds. The only slight deviation from the ISIS method was that, whenever open water was sampled, the water surface was first observed to establish the presence of surface dwelling invertebrates such as Pondskaters or Whirligigs. These have a habit of escaping out to open water as soon as the net enters the water; therefore when present they were caught prior to the ISIS methodology being employed. This methodology may be summarised thus: The sampling method standardises effort by bank-sorting three qualitative hauls for 10 minutes each, giving 30 minutes of sorting. The emphasis is on free-style netting of features (microhabitats) that are likely to be the most productive. Effort is deliberately not divided in proportion to the extent of features since species are not distributed in this fashion. The net used was the standard FBA design with a rectangular frame 25cm wide and 22cm long, the net bag 30cm deep with a 1mm mesh. While standing in or at the water margin, the vegetation was netted using short jabbing thrusts in any dense emergent and raft-forming plants, and using occasional longer strokes into submerged plants and over bare substrate in deeper water. This was repeated along the bank as netting proceeded, selecting patches of vegetation that exhibited the greatest small-scale mosaic structure since these patches yield more specimens. Netting ended when the net began to fill to the point that it became more difficult to push, usually after about 1 to 3 minutes when it was usually about a third to a half full of plant material. When duckweed or similar small plants were abundant, the net would fill within seconds, so some careful manipulation was needed to slow the rate that it was caught while probing for more productive structures beneath. Bottom sediment was avoided since it clogs the net and contains almost no species that contribute to the analysis, though ‘grazing’ strokes across the sediment top were used to ‘put up’ invertebrates such as beetles and bugs which were then caught in the net. Once the net was full a digital timer was used to time the 10 minutes sorting time as the sample was tipped onto a white polythene sheet and spread out quickly into a thin layer. Fast-crawling beetles, bugs and dragonfly larvae were collected or identified (if recognisable) before they escaped during the spreading-out process. Many invertebrates, such as flatworms and leeches react badly to the alcohol used as a sample preservative, others such as Water Scorpion or Stick Insect are instantly identifiable. During sorting these were placed in a bucket of water. They were then identified, noted and returned alive to the water.
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The white sheet was then scanned for other animals as they recovered from their shock. After a few minutes, the debris was turned over and poked about, when more animals were usually found. A pool of water forms in the centre of the sheet which allows weakly swimming animals a refuge and to be seen, these were collected towards the end of each 10 minute time period. Fine flexible forceps were used for picking up animals; a tea strainer and white plastic spoon were used to ‘net’ animals in the pool in the middle of the sheet. However a wet finger was often the best tool to pick up really small beetles and bugs. All were immediately put into a wide mouthed bottle containing 70 % alcohol. During the last two minutes of the search some of the debris was put into a white tray with 1-2cm depth of water. Feeble animals which swim free were collected. Lastly all plant material was tipped into a bucket of water, larger pieces and most of the water was removed. The heavy residue was tipped into the white tray with about 1cm of water. Then by tipping the contents to and fro, the molluscs left stranded in a pile were collected. At each sample site this operation was repeated twice more at bank sections about 25m apart.
This protocol results in one tube of animals per sample site which was then identified back in the laboratory. As no large amounts of debris or plant material are collected the identification process is much easier and needs no pre-sorting which is very time consuming and therefore costly. Survey Results This section contains the full list of invertebrates recorded at Oulton Marshes. The usual practice for such a table is to have a column for each site showing presence or absence of each species. In view of the large number of sites surveyed this was felt to be confusing and so instead the presence or absence of each species is shown for original (TPo) or new turf ponds (TPn), for existing ponds (P) and for dykes (D). In order to make table 2 a complete list which is easy to check it includes some additional records and uses the following symbols:
Ф
indicates that a species was recorded from at least one Turf Pond indicates species presence in an existing pond(s) is the symbol for species recorded from dykes
Species named in bold are new to the Suffolk fauna. Numbered rows indicate invertebrates recorded in the current survey, additional species only found in 2012 or by Wheatfen Partnership have * instead of a number. For completeness data on any amphibians or fish encountered are included as well as all 174 invertebrates.
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Suffolk Natural History, Vol. 51 Table 2: Full Species List
TPo TPn Family Species Description Status Acari ... Water Mites (Do not count towards BMWP or CCI scores) Hydracarina Water Mite sp. Water Mites Amphibia ... Amphibians (Do not count towards BMWP or CCI scores) Ranidae Rana temporaria Common Frog Salamandridae Lissotriton vulgaris Smooth Newt Amphipoda ... freshwater shrimps or scuds Crangonyctidae Crangonyx pseudogracilis An American Freshwater Locally Shrimp common Gammaridae Gammarus pulex A Freshwater Shrimp Very Common Oligochaeta ... True Worms (Do not count towards BMWP or CCI scores) Oligochaetae Oligochaeta sp. A True Worm Cladocera ... Water Fleas (Do not count towards BMWP or CCI scores) Bosminidae Bosmina longirostris Common Long-nosed Water flea Bosminidae Bosmina longirostris Horned Common var. cornuta Long-nosed Water flea Chydoridae Chydorus sphaericus Common Ball Water flea Chydoridae Pleuroxus denticulatus A Water Flea Daphniidae Ceriodaphnia pulchella A Water Flea Daphniidae Ceriodaphnia A Water Flea quadrangula Daphniidae Ceriodaphnia reticulata A Water Flea Daphniidae Ceriodaphnia setosa A Water Flea Daphniidae Daphnia curvirostris A Water Flea Daphniidae Daphnia longispina Long-tailed Water flea Daphniidae Daphnia obtusa A Water Flea Daphniidae Scapholeberis mucronata The Meniscus Water flea Daphniidae Scapholeberis mucronata The Meniscus Water flea f. cornuta Daphniidae Simocephalus vetulus Small-headed Water flea Eurycercidae Eurycercus lamellatus Giant Crawling Water flea Polyphemidae Polyphemus pediculus Predatory Giant Eyed Water flea Sididae Sida crystallina Crystal Water flea Coleoptera ... Water Beetles Chrysomelidae Chrysomelidae sp. A Reed Beetle - non aquatic Curculionidae Curculionidae sp. A Weevil larva Dryopidae Dryops sp. A water beetle larvae Dytiscidae Acilius sulcatus A Diving Beetle Common Dytiscidae Agabus bipustulatus A Diving Beetle Very common Dytiscidae Agabus nebulosus A Diving Beetle Very common Dytiscidae Agabus sp. A Diving Beetle larva Dytiscidae Colymbetes fuscus A Diving Beetle Very common Dytiscidae Dytiscus circumcinctus A Great Diving Beetle Na Dytiscidae Dytiscus marginalis A Great Diving Beetle Very common Dytiscidae Hydaticus seminiger A Diving Beetle Nb Dytiscidae Hydaticus transversalis A Diving Beetle RDB3 Dytiscidae Hydroglyphus geminus A Lesser Diving Beetle Nb Dytiscidae Hydroporus angustatus A Lesser Diving Beetle Common Dytiscidae Hydroporus palustris A Lesser Diving Beetle Very common 2012 only Dytiscidae Hydroporus pubescens A Lesser Diving Beetle Common
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PD
Ф Ф Ф Ф
41
AQUATIC INVERTEBRATE SURVEY OF OULTON MARSHES Family Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Dytiscidae Gyrinidae Gyrinidae Gyrinidae Gyrinidae Haliplidae Haliplidae Haliplidae Haliplidae Haliplidae Haliplidae Haliplidae Helophoridae Helophoridae Hydraenidae Hydraenidae Hydrophilidae Hydrophilidae Hydrophilidae Hydrophilidae
Species Hygrotus impressopunctatus Hygrotus inaequalis Hyphydrus ovatus Ilybius ater Ilybius fuliginosus Ilybius quadriguttatus Ilybius sp. Laccophilus hyalinus Laccophilus minutus Rhantus grapii Rhantus suturalis Gyrinus caspius Gyrinus marinus Gyrinus sp. Gyrinus substriatus Haliplus immaculatus Haliplus lineatocollis Haliplus obliquus Haliplus ruficollis Haliplus sp. Haliplus variegatus Peltodytes caesus Helophorus griseus Helophorus minutus Hydraena riparia Ochthebius minimus Anacaena limbata Berosus affinis Enochrus testaceus Helochares lividus
Description A Lesser Diving Beetle
Status Local
A Lesser Diving Beetle Common A Lesser Diving Beetle Common A Diving Beetle Common A Diving Beetle Very common A Diving Beetle Common A Diving Beetle larva A Lesser Diving Beetle Very common A Lesser Diving Beetle Local A Diving Beetle Nb A Diving Beetle Nb The Caspian Whirligig Local The Mariner Whirligig Common A Whirligig The Common Whirligig Very common A crawling water beetle Local A crawling water beetle Very common A crawling water beetle Local A crawling water beetle Very common A crawling water beetle larva A crawling water beetle RDB3 A crawling water beetle Nb A Mud Beetle Nb A Mud Beetle Common A Water Beetle Local A Water Beetle Very common A Water Scavenger Beetle Very common A Water Scavenger beetle Nb A Water Scavenger Beetle Local A greenish brown water Nb scavenger beetle Hydrophilidae Laccobius bipunctatus A Water Scavenger Beetle Very common Hydrophilidae Laccobius colon A Water Scavenger Beetle Local Noteridae Noterus clavicornis Larger species of Noterus Local Noteridae Noterus crassicornis Smaller species of Noterus Nb Paelobiidae Hygrobia hermanni The Screech Beetle Local Scirtidae Scirtidae sp. A Marsh beetle larva Collembola ... Surface Dwelling Springtails (Do not count towards BMWP or CCI scores) Isotomidae Isotomurus palustris A Surface Dwelling Springtail Sminthuridae Sminthurides aquaticus A Surface Dwelling Springtail Diptera ... Fly Larvae Chaoboridae Chaoboridae sp. Phantom Midge Larvae Chaoboridae Chaoborus crystallina A Phantom Midge Chironomidae Chironomidae sp. Non Biting Midges Culicidae Anopheles sp. Mosquito larvae Culicidae Culex sp. Mosquito larvae Culicidae Culicidae sp. Mosquito larvae Dixidae Dixa sp. A Meniscus Midge Muscidae Lispe sp. Aquatic Larvae of House or Stable Flies Stratiomyidae Nemotelus sp. Larva of a Soldier Fly
TPo TPn P D
Ф Ф Ф Ф Ф Ф Ф Ф Ф Ф Ф
2012 only 2012 only 2012 only
Ф Ф Ф Ф Ф Ф
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Table 2. continued Family Stratiomyidae Stratiomyidae
Species Nemotelus sp. Odontomyia ornata
Stratiomyidae Oplodontha sp. Tipulidae Tipula sp. Ephemeroptera ... Mayflies Baetidae Cloeon dipterum Caenidae Caenis horaria Caenidae Caenis sp. Hemiptera ... Aquatic Bugs Corixidae Callicorixa praeusta Corixidae Corixa panzeri Corixidae Corixa punctata Corixidae Cymatia coleoptrata Corixidae Hesperocorixa linnaei Corixidae Hesperocorixa sahlbergi Corixidae Paracorixa concinna Corixidae Sigara distincta Corixidae Sigara dorsalis Corixidae Sigara fossarum Corixidae Sigara iactans Corixidae Sigara lateralis Corixidae Sigara limitata Corixidae Sigara venusta Gerridae Aquarius paludum Gerridae Gerris lacustris Gerridae Gerris lateralis Gerridae Gerris odontogaster Gerridae Gerris sp. Gerridae Gerris thoracicus Hydrometridae Hydrometra stagnorum Naucoridae Ilyocoris cimicoides Nepidae Nepa cinerea Nepidae Ranatra linearis Notonectidae Notonecta glauca Notonectidae Notonecta maculata Notonectidae Notonecta viridis Pleidae Plea minutissima Veliidae Microvelia reticulata Hirudinea ... Leeches Erpobdellidae Erpobdella octoculata
Status
The Pond Olive White Midge White Midge - early instar
Very Common Common
A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman A Lesser Water Boatman Spined Skater The Common Pond Skater
Ф Frequent Local Ф Very common Frequent Ф Occasional Common Local Occasional 2012 only Very common Common Unknown Common Local Occasional Nb Very common 2012 only Local Common 2012 only Ф Occasional Very common Ф Local Frequent Local 2012 only Ф Very common Local Ф Local Ф Local Ф Local
A Pond Skater The Toothed Pond Skater A Pond Skater nymph A Pond Skater The Water Measurer Greater Saucer Bug Water Scorpion Water Stick Insect Common Water Boatman A Water Boatman A Water Boatman A Lesser Waterboatman A Lesser Water Cricket
A Leech of aquatic Invertebrates Erpobdellidae Erpobdella testacea A Leech of aquatic invertebrates Glossiphoniidae Glossiphonia complanata A Leech of molluscs, insect larvae Glossiphoniidae Helobdella stagnalis A Leech of aquatic invertebrates Glossiphoniidae Theromyzon tessulatum The Duck Leech Piscicolidae Piscicola geometra The Fish Leech
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TPo TPn P D Ф
Description Larva of a Soldier Fly The Ornate Brigadier Soldier Fly larva Larva of a Soldier Fly Larva of a Crane Fly
Unknown
Ф
V common
Occasional
V common
V common
Common Common
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AQUATIC INVERTEBRATE SURVEY OF OULTON MARSHES Family Species Description Isopoda ... Water Slaters or Hog Lice Asellidae Asellus aquaticus A water Slater or Hog Louse Megaloptera ... Alder Flies Sialidae Sialis lutaria The Common Alder fly Mollusca ... Bivalve and Univalve Mussels & Snails Acroloxidae Acroloxus lacustris Lake Limpet Bithyniidae Bithynia leachii Leach’s Bithynia Bithyniidae Bithynia tentaculata Common Bithynia Lymnaeidae Lymnaea fusca Marsh Snail Lymnaeidae Lymnaea stagnalis Great Pond Snail Lymnaeidae Radix balthica Wandering Snail Physidae Physa fontinalis Fountain Moss Bladder Snail Planorbidae Anisus vortex Whirlpool Ramshorn Planorbidae Bathyomphalus Contorted Ramshorn contortus Planorbidae Gyraulus crista Nautilus Ramshorn Planorbidae Hippeutis complanatus Flat Ramshorn Planorbidae Planorbarius corneus Great Ramshorn Planorbidae Planorbis carinatus Keeled Ramshorn Planorbidae Planorbis planorbis The Ramshorn Sphaeriidae Musculium lacustre Lake or Capped Orb Mussel Sphaeriidae Pisidium nitidum Shining Pea Mussel Sphaeriidae Pisidium sp. Unknown Pea Mussel Sphaeriidae Sphaerium corneum Horny Orb Mussel Succineidae Succinea putris Amber Snail - terrestrial Valvatidae Valvata cristata Flat valve snail Viviparidae Viviparus contectus Lister's River Snail Odonata ... Damselflies & Dragonflies Aeshnidae Aeshna cyanea The Southern Hawker Aeshnidae Aeshna grandis The Brown Hawker Aeshnidae Aeshna mixta The Migrant Hawker Aeshnidae Anax imperator The Emperor Dragonfly Aeshnidae Brachytron pratense The Hairy Dragonfly Coenagrionidae Ceriagrion tenellum The Small Red Damselfly Coenagrionidae Coenagrion puella The Azure Damselfly Coenagrionidae Enallagma cyathigerum The Common Blue Coenagrionidae Ischnura elegans The Blue-tailed Damselfly Lestidae Lestes sponsa The Emerald Damselfly Libellulidae Libellula depressa The Broad-bodied Chaser Libellulidae Libellula quadrimaculata The Four-spotted Chaser Libellulidae Orthetrum cancellatum The Black-tailed Skimmer Libellulidae Sympetrum sanguineum The Ruddy Darter Libellulidae Sympetrum striolatum The Common Darter Ostracoda ... Ostracods (Do not count towards BMWP or CCI scores) Notodromadidae Notodromas monacha A surface dwelling Ostracod Ostracoda sp. An Unidentified Ostracod Pisces ... Fish (Do not count towards BMWP or CCI scores ) Gasterosteidae Gasterosteus aculeatus 3 Spined Stickleback Gasterosteidae Pungitius pungitius 9 Spined Stickleback
Status
TPo TPn P D
Common
Common
Common Local Very common Common Very common Very common Very common Very common Common Common Frequent Frequent Very common Very common Occasional Occasional
Very Common Common Common Occasional Occasional increasing RDB3 Common Very Common Very common Local Common Common Common Frequent Very common
Ф Ф Ф Ф
Ф
Ф Ф
Very common Very common Common Local
Ф Ф Ф
Ф
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Table 2. continued Family Species Trichoptera ... Caddis or Sedge Flies Hydroptilidae Agraylea sexmaculata
Description
A purse cased micro caddis (primitive type) Leptoceridae Athripsodes aterrimus A cased caddis 'A Brown or Black Silverhorn' Leptoceridae Leptocerus tineiformis A cased caddis Leptoceridae Triaenodes bicolor A cased caddis 'The Bicolour Sedge' Limnephilidae Chaetopteryx villosa A cased caddis Limnephilidae Limnephilus flavicornis A cased caddis Limnephilidae Limnephilus marmoratus A cased caddis 'The Cinnamon Sedge' Limnephilidae Limnephilus sp. A cased caddis larva early instar Phryganeidae Agrypnia pagetana A cased caddis Phryganeidae Phryganea bipunctata A cased caddis 'The Great Red Sedge' or 'Murragh' Phryganeidae Phryganea grandis A cased caddis 'The Great Red Sedge' or 'Murragh' Sericostomatidae Sericostoma personatum A cased caddis 'The Welshman's Button' Tricladida ... Free Living Flatworms Dendrocoelidae Dendrocoelum lacteum A Freshwater Triclad or Flatworm Dugesiidae Dugesia lugubris A Freshwater Triclad or Flatworm Dugesiidae Dugesia polychroa A Freshwater Triclad or Flatworm Planariidae Polycelis nigra A Freshwater Triclad or Flatworm Planariidae Polycelis nigra / tenuis A Freshwater Triclad or Flatworm
Status
TPo TPn P D
Local
Very common
Local Common
Common Common Common
Local Common
Local Very common
Common Common
Common
Ф
Very common Very common
Discussion of Results The invertebrate community The survey showed an invertebrate community on Oulton Marshes which was composed principally by: Coleoptera (Water Beetles): 52 species Hemiptera (Aquatic Bugs): 29 species Mollusca (Water snails and bivalves): 21 species Cladocera (Water Fleas) 17 species Odonata (Dragonflies and Damselflies) 15 species Trichoptera (Caddis Flies) 12 species Diptera (Fly larvae / pupae) 12 not all identified to species Others 24 not all identified to species Two amphibian and two fish species were also noted.
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Original and New Turf Ponds 16 species were recorded only from the original turf ponds, which were 3 years old when this report was written. 7 extra species had been found in original turf ponds in 2012 but were not recorded again. 8 species were found only in new turf ponds, 1 year old at time of writing. 10 further species were found in both old & new turf ponds and in no other type of site. So in this survey 34 species out of 174 were only recorded from turf ponds, which is 20% of the observed fauna. It therefore seems extremely likely that the construction of the turf ponds has provided additional habitat niches which freshwater invertebrates have utilised. Existing Ponds and Dykes: 2 species (1%) were only found in the existing ponds. 61 species (35%) were found only within the dykes sampled. 75 species (43%) were recorded from both dykes and ponds (turf and/or existing ponds) Only 3 species recorded by the Wheatfen Partnership in 2010 were not rerecorded. 136 species were recorded from dykes compared to 38 in the Wheatfen Survey There was little similarity between the fauna of the existing ponds and turf ponds. The two Coopers Marsh ponds had only two of the unique turf pond species but contained 30% of the dyke species list. Two species were unique to the existing ponds, of which Gyraulus crista is discussed below. Whether the unusually high conductivity and total dissolved solids of these ponds have anything to do with this lack of similarity or whether it is solely a result of succession and the maturation of these ponds, even with the cleaning out in 2011, cannot be ascertained. Clearly most of the species were found in both turf ponds and/ or ponds and dykes; so the new habitats have suited the majority of invertebrates. A large number of dyke species did not or have not yet colonised the turf ponds; for many such as snails or leeches this will doubtless be slow dispersal and they may yet colonise. However a fifth of the total list were only found in turf ponds which is an indication that many invertebrates found this new habitat more favourable than the existing dykes. A large proportion of these were beetles, bugs, caddis etc., which are species good at dispersal and will have flown in as adults to feed or to lay eggs. When overflying the reserve they appear to have chosen the turf ponds in preference to the dykes which are more extensive waterbodies. Some of these may well be pioneer species and it could be that eventually they move on as this successional habitat matures. Other species may well have been introduced by birds or mammals or for some groups, for example the Cladocera, resting eggs buried within the disturbed marsh may have hatched out when light and water reawakened them.
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Referring now to the six questions posed in the survey aims it seems clear that: The construction of the turf ponds has increased the range of habitat types available to aquatic invertebrates within the reserve. This survey and the Wheatfen Partnership survey are not directly comparable as methodologies and the number of sites surveyed were different. However, although it is a somewhat crude measure of biodiversity, almost 100 more species were found in 2013–14 than in 2008. The conclusion must therefore be that: The biodiversity of the aquatic invertebrate community has increased since the Wheatfen Partnership Survey in 2010. The figures above also show that the results from the turf ponds do not simply mirror the general dyke community but contribute 34 extra species to the invertebrate biodiversity of the reserve. What was the source of turf pond invertebrate communities? The majority of turf ponds are clustered in two areas, Rists Marsh and Rede Marsh. For both of these a marginal dyke was included as one of the sample sites so that the two communities could be compared. In the 6 turf ponds in Rists Marsh There were 115 species altogether, 34 (29%) occurred in both the turf ponds and the marginal dyke, 25 (22%) occurred only in the dyke, 56 (49%) were found only in the turf ponds in centre of marsh. In the 3 turf ponds in Rede Marsh There were 82 species altogether, 14 (17%) occurred in both the turf ponds and the marginal dyke, 25 (31%) only in the dyke, 43 (52%) were found only in the turf ponds in centre of marsh. Therefore in both cases around half of the invertebrates found had not dispersed from the nearest dyke and had arrived from elsewhere. Looking closer at those species which had not dispersed from the adjacent dykes. In Rists Marsh 56 species were found in those 6 turf ponds but not in the Rists Marsh Dyke, 27 of those 56 were not found elsewhere on the reserve. In Rede Marsh 43 species were found only in those 3 turf ponds but not in the adjacent dyke and 14 of them were found nowhere else.
Referring back once again to the questions posed in the introduction: Invertebrate communities in the turf ponds would seem to be recruited only in part by dispersal from the nearest dykes and in part from across the reserve in general but the remainder seem to have arrived from elsewhere, that is from outside the reserve. The next question asked if there was a similarity between the new turf pond communities and that of the two older, pre-existing ponds: Pond 1 had a species count of 35 and the adjacent pond 2 of 37. The lists, as might be expected, are very similar with 27 species being in both lists. If these two ponds are similar to the new turf pond communities then they will contain some of the 38 species found in turf ponds but not in dykes. In fact only 4 of these species were also Trans. Suffolk Nat. Soc. 51 (2015)
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found in the existing ponds. These two ponds together yielded 45 species of which 39 also occurred in the dykes, 2 were unique to the ponds. These old ponds then have a fauna 86% of which is similar to the dykes. So the conclusion must be that the pond community is not similar to the new turf ponds, although this may be complicated by the unusual water characteristics, the age of the ponds and therefore the successional stage they have reached, even though they were both cleaned out in 2011. There is a similarity between the invertebrate community of the two old ponds and that of the dykes but little similarity with that of the turf ponds. Species Discussion Here the ecology, status and distribution of any interesting, scarce or rare species found during the survey are discussed from a national and / or county perspective. Status values are those used for the calculation of CCI (Chad & Extence, 2004), see also Section 6: Analysis Results. Species new to the Suffolk fauna are marked thus **. Distribution data for water fleas comes from the atlas recently published by the Cladocera Interest Group (www.cladocera.org.uk) with the aid of the CEH. All records from Oulton Marshes have been incorporated into this on line atlas. Local distribution data for other orders is taken from the Freshwater Invertebrate Survey of Suffolk database which I maintain as county recorder, national data is sourced from various publications listed in Section 7: References. Water Fleas: Cladocera Pleuroxus denticulatus is a tiny water flea of the Chydoridae family, the larger female being only about half a millimetre across, when males appear they are only half that size. There are only 10 previous records of this species in the British Isles, all of which occur south of a line from Bristol to the Wash. Oulton joins only two other UK sites found since the millennium, one of which was in Suffolk at Elveden. An important county record therefore. Ceriodaphnia setosa ** is a larger species, almost 1 mm in size but is an even more important record since Oulton becomes only the fourth known site in the UK for this water flea, the other records being from Norfolk, Hertfordshire and South Wales, the last being the only other record since the millennium. This then is a rare water flea and a new addition to the Suffolk species list. Only parthenogenetic females were found. Polyphemus pediculus can grow up to 2 mm long but all the specimens from the Soke Dyke were smaller than this. Although the distribution in the UK is widespread and there are many more records than the two previous species, the Oulton record is notable as this is only the third time it has been found in Suffolk. Lound Lakes and the River Stour at Flatford being the other county sites. The common name of The Predatory Giant Eyed Water Flea has been coined for this animal; which is quite apt as it is unusual in being one of the few plankton predators that feed visually, using those large eyes. It can form dense swarms along the shores of lakes, moving out into the
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Sida crystallina is one of the larger water fleas being around 2.5 mm across, however it is so transparent that the Crystal Water Flea is often very hard to see in a white sorting tray. The photograph is specially taken through the microscope to show it and the internal organs clearly. There are widespread records from across the British Isles, though most of these are many decades old with only 7 other records since 2000. Oulton is the third Suffolk record, accompanied by nearby Lound Lakes and the Flatford Stour once again, which probably says more about my recording destinations than water flea distribution in the county!
Photo: Phillip Greaves
open water at night to hunt down smaller zooplankton prey, especially rotifers. It is named after Polyphemus the one eyed, man eating giant which Odysseus met returning from the Trojan Wars.
Freshwater Beetles: Coleoptera Dytiscus circumcinctus is one of 6 Great Diving Beetle species in the UK the most common of which, Sida crystallina 2.5 mm Dytiscus marginalis, was also found at Oulton. D. circumcinctus was listed as Nationally Scarce in the JNCC review of 2010. First recorded in Suffolk by Claude Morley in 1911 there is only one other Suffolk record of D. circumcinctus from Languard Point in 2006 thus Oulton is only the third site in the county. The species is a typical resident of coastal levels in well vegetated permanent, still water and can be distinguished by the pale underside and long, sharp points where the hind legs join the body (the metacoxal processes).
Hydaticus seminiger & Hydaticus transversalis**. There are two species of Hydaticus in Britain, both are present at Oulton and both are classed as Near Threatened. For H. seminiger my database has 13 previous records from Dytiscus circumcinctus 31 mm 5 sites, including several from Redgrave Fen; however H. transversalis is a new Suffolk county record. Before its discovery at Oulton the latest data from the unpublished water beetle atlas was that ‘H. transversalis is found in permanent, densely vegetated pools and ditches in old fenland areas around the Severn, in the Cambridgeshire fens and in the Broads. The confirmed occurrence at two sites on St. Mary’s in the Scillies, emphasises the potential mobility of this species’ (Garth Foster pers. comm.) Thus the habitat at Oulton, being part of the Suffolk Broads fits perfectly with the national records. The recent Scilly Isles records confirm its flight capability, which some authorities had
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doubted, and make it worth searching for across the water at Carlton Marshes Reserve where the habitat is also suitable. Hydroglyphus geminus is represented by 7 previous records on my database since first found in 1889, so the 2 records from this survey are a useful addition. The coleoptera status review indicates that this species is becoming wider spread than previously thought. Interestingly, the first Suffolk record for Rhantus grapii was from Oulton Broad, by Claude Morley in 1899. Since then we have just 7 sites for the species, all in very similar habitats with the most records coming from Redgrave and Lopham Fens. Finding it in two sample sites at Oulton Marshes re-establishes its presence after 115 years. A lowland species whose distribution follows old fenland and marsh across mainly Southern England it is yet another indication that habitat restoration on the reserve is proving very successful. Haliplidae: Haliplid beetles are a group of small, crawling water beetles which, both as adults and larvae, are mainly algivorous though adults also eat sponges and hydra. Some species are also associated exclusively with stoneworts (Characeae), a family of complex-structured algae which play a significant role in ecological succession and the community structure of many types of water body. Therefore, depending on species found, the Haliplidae at a site can be useful indicators of habitat quality. Haliplus obliquus is one of the species associated with base rich habitats supporting stoneworts and was only found in the new turf ponds where stonewort growth was usually strong. H. obliquus was not found in the original turf ponds where reed growth had already become extensive and stonewort growth appeared to be reduced. There are 20 other records on the county database. Haliplus variegatus is an uncommon species of stagnant fens, again in association with its food stoneworts. It is listed in the latest review as Vulnerable, Near Threatened and states that ‘Management that retains some peat substratum with permanent, base-enriched water appears to be appropriate for this species’. H. variegatus was first recorded in Suffolk by Morley in 1894; since then there have been 3 records from Redgrave and Lopham Fen and one from Minsmere. This is certainly a rare species in Suffolk and the single specimen recorded in Turf Pond 4 is an important county record; management of this original turf pond or the creation of new ponds to allow continued good stonewort growth will be needed to maintain its presence. Peltodytes caesus is another indicator of good quality habitat being confined to lowland rich fen pools and ditches in the Welsh and English fens from the Bristol Channel to Norfolk. Listed in the latest review as Nationally Scarce, it was first recorded in Suffolk at Bungay in 1858. Claude Morley found it in Oulton Broad in 1898 and 1900 so it is pleasing to find that it is still nearby 114 years later. It has been recorded at 5 other sites since 1900, including the adjacent Carlton Marshes Reserve by myself in 2010.
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Helophorus griseus is no longer listed as Nationally Scarce in the Coleoptera review 2010 as it is more widespread than previously thought. Nevertheless it is a species which has a conservation value being an indicator of good quality sites such as Oulton. As far as Suffolk is concerned with only 6 other records since the first in 1988 this is very useful indeed. Berosus affinis is a small beetle of well vegetated pools and drainage ditches with some exposed substratum. The habitat at Oulton is therefore well suited, although only one female specimen was found in one of the new turf ponds. The distribution of this species in Britain is mostly confined to the south. In the Suffolk database we have records from 8 other sites, however 5 of these are archive data before 1900 and the rest comprise 1 record from 2004 and 2 from 2010. Oulton is important as only the fourth modern site for this species. Noterus crassicornis and the very similar looking Noterus clavicornis are both common on this site and are typical of base rich fen and grazing level drainage ditches though N. crassicornis is the scarcer of the two being now listed as Nationally Scarce. Along with the 10 records from this survey there are 14 previous entries in my database 6 from the Oulton area with 5 from Lopham Fen and 3 from other areas of the county. N. clavicornis is well represented on the county database from widespread sites across the county. Fly Larvae: Diptera Odontomyia ornata ** The Ornate Brigadier Soldier Fly (Plate 10) was found during the survey as a larva and identified with the help of the county recorder Peter Vincent. The following advice is taken from the key by Stubbs and Drake (2001). ‘The species is widespread & not uncommon in the Somerset and Gwent Levels with sizeable populations on East Sussex coastal levels. Elsewhere including Suffolk & Norfolk records are sparse. The larvae are found in ditches on grazing levels, often near the surface amongst floating vegetation such as ivy leaved duckweed & frogbit. It prefers ditches wider than 1 metre with a rich & structurally diverse cover of floating vegetation. The key to its survival are extensive ditches cleared on a cycle of about 5 years. Almost confined to grazing marshes, it is a good flagship species for this habitat.' This would seem to be the first county record for larvae of this species and hence the first known breeding site. Aquatic Bugs: Hemiptera Ilyocoris cimicoides The Greater Saucer Bug is found in base rich, still waters which are normally muddy bottomed and usually amongst dense vegetation I. cimicoides is often found either in very large numbers or not at all. It is frequently found in one location but not in a neighbouring waterbody. It has been postulated that populations are self-limiting due to poor dispersal caused by reduced wing musculature in a high proportion of adults. At Oulton the population was truly staggering and denser than at any site I have seen. Clearly the dense matrix of highly vegetated waterbodies and the current management suits this species well, facilitating dispersal across the site.
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Microvelia reticulata This Lesser Water Cricket, a surface dwelling bug, was found in small numbers at several of the sample sites but, being less than 1.5 mm long, it is certainly rarely seen and probably is present in very large numbers. It is found in many types of still water but always amongst emergent, marginal vegetation as here. Due to its tiny size the species is probably under recorded though clearly widespread and more often recorded in the south and east of Britain. A related but much rarer species Microvelia pygmaea was not recorded during this survey but there are some records for this species from sites very close by. Both species do occur together at sites elsewhere in East Anglia and it will be important to search also for M. pygmaea in any future surveys. Paracorixa concinna is a Lesser Water Boatman widely distributed throughout Britain, which is most frequent in the south but is rarely common. A mobile species it tends towards small transitory populations, possibly because of competition with other corixids. However it does favour open waters of moderate size with high conductivity. It was found in two of the original turf ponds adjacent to each other in Rists Marsh. Conductivity is reasonably high in most areas of the reserve so why these particular ponds were chosen is unclear. The Suffolk database only contains only 7 other sites where P. concinna has been found since the year 2000. Ranatra linearis The Water Stick Insect was often found in larger numbers than normal during the survey especially in turf ponds. The habitat at this site is however typical for R. linearis being an open site with large amounts of emergent vegetation. Specimens were also found in dykes but in much smaller numbers than in the turf ponds. In Britain Ranatra is predominantly a species of the south east but even so in Suffolk it is only recorded from 32 out of over 750 surveyed possible sites. Oulton Marshes is obviously a stronghold for this species but it is certainly not restricted to fen drains or marshes being occasionally recorded from all site types from small farm ponds to rivers. Sigara limitata A Lesser Water Boatman which is a difficult species to quantify. Although widely distributed in Britain and more frequent in the south and east there are only records from 79 10 km squares in the provisional atlas of British aquatic bugs (Huxley, 2003). Records come from habitats as diverse as moorland ponds and chalk streams, so it can hardly be described as fussy! As for the Suffolk database, Oulton Marshes is only the 9th site added since 2000 and only one of the other sites is a reedbed so habitat preferences and management considerations remain to be resolved. Sigara venusta is a Lesser Water Boatman I was pleased to see again. The first record I have for this species was in 1960, then there is a gap of 28 years followed by 12 records from 1988 to 1994. Since then it had vanished again despite searching old sites for it. The national distribution is also widespread but patchy, missing from large swathes of the country but very widespread. Neither pH nor conductivity seem to be limiting factors so it may be hoped that this record heralds a return for the species in Suffolk.
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Aquarius paludum is often called the Spined Pondskater and being larger than all the other skaters in Suffolk, together with two obvious projections at the end of the abdomen (arrowed) it is easy to recognise. This is another insect I was surprised to see at Oulton since the only other two sites known in Suffolk are large oligotrophic lakes. In these other sites it occurs in colonies numbering several thousand individuals, at Oulton I found just one male on one of the new turf ponds. Elsewhere in the country A. paludum can be found on streams and rivers as well as lakes and so there is a possibility that this lone individual strayed from the nearby Oulton Dyke or even the Soke Dyke. Both of these have the wide, open stretches of water with dense cover by the banks which this species seems to love. An important Suffolk record then which will repay further research. Both potentially suitable dykes are wide and deep but fortunately this insect is easily seen and identified with binoculars. Gerris lateralis is a very rare pondskater in Suffolk. Very similar to the common species G. lacustris but both nationally and locally it has a sparse, scattered distribution. Generally more common in northern Britain there are scattered records as far south as the M25. In Suffolk there is one rather dubious record from Sudbury in 1958, otherwise there are only two previous records from Butchers Marsh, Oulton and one from Minsmere. In September 2014 it was taken from the edge of the Soke Dyke in shallow water amongst emergent vegetation, which is appears to be its preferred habitat. Freshwater Snails: Mollusca Oulton Marshes is a site rich in aquatic molluscs with 21 species recorded during the survey, whilst none of the species recorded are rare either nationally or in Suffolk two are worthy of mention. Gyraulus crista, the Nautilus Ramshorn is tiny, being about 3mm across and the smallest of all our ramshorns with characteristic but very variable ridges and spines. Probably under recorded due to its size it is quite common across the county and is tolerant of a variety of conditions, occurring in some rivers and the occasional roadside ditch although most of our records come from smallish ponds of similar size to the two original ponds here at Oulton. It would seem that the turf ponds should be suitable habitat also so it will be interesting to see if G. crista appears in them. Given its size accidental introduction by birds or animals would seem the only likely route. It was not found in any of the dykes during the survey though I can see no reason it should not be. Trans. Suffolk Nat. Soc. 51 (2015)
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Viviparus contectus the Freshwater Winkle or River Snail is a large species up to 35 mm wide and mostly is recorded in rivers. At Oulton it is common in the dykes where it was usually found towards the bottom of the water column. Records of this species are mostly restricted to the river systems forming Suffolk’s county boundaries and as such is always an interesting find. Caddis or Sedge Flies: Trichoptera All the records below refer to larvae. Agraylea sexmaculata ** (Plate 11). This is a very small micro-caddis fly when adult and the larva is only about 3mm long within the purse shaped case which it weaves from strands of algae stuck together by a secretion which it produces from a gland on the thorax. The three records from Oulton are the first records for larvae made in Suffolk, there is also only one record of the adult which was found in a moth trap at Hollesley in 2013. Leptocerus tineiformis ** (Plate 12), is also a new county record for the larvae of this species. Adults of L. tineiformis were recorded by Claude Morley from Fritton Lake several times between 1904 and 1935. The next adult records were made in Hollesley in 2013 but Oulton is the first definite larval record for L. tineiformis showing the type of habitat in which it breeds in Suffolk. Overall Conclusions The results of this survey show that management during the last four years has brought about considerable improvement in the freshwater ecosystem, in terms both of the biodiversity of the invertebrate community and of the water quality. The analysis above shows that across the reserve both of these two key factors are at present in excellent condition. The digging of the turf ponds was in some ways experimental but has proved to be very successful in further increasing the biodiversity and conservation value of the reserve. Survey results indicate that creating turf ponds provides a different and scarce habitat which is readily exploited by species additional to those already on the site, many of which are likely to be of important status nationally. Comparing the analysis results with other sites in the county shows that Oulton Marshes surely ranks amongst the best freshwater habitats in Suffolk and it has recently been adopted as a Flagship Pond site by the Freshwater Habitats Trust. References Data used in the discussions in this report are taken from the database of the Freshwater Invertebrate Survey of Suffolk and also from: Buckle, P. Dec 23, (2011). Identification of Freshwater and Brackish-water Snails of Britain and Ireland. The Conchological Society of Great Britain and Ireland. Retrieved 10 August, 2013. from: http://www.conchsoc.org/aids_to_id/fwidbase.php Chadd, R. & Extence, C. (2004). The conservation of freshwater macroinvertebrate populations: a community-based classification scheme. Aquatic Conserv: Mar. Freshw. Ecosyst. 14: 597–624
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Chalkley, A. K. (2012). An Initial Survey of Three Turf Ponds at Oulton Marshes SWT Reserve. Downloadable from: http://www.suffolkwildlifetrust.org/sites/default/files/oulton_marshes_report.pdf Duffy, L. K. & Weber-Scannell, P. K. (2007). Effects of Total Dissolved Solids on Aquatic Organisms. American Journal of Environmental Sciences 3 (1): 1–6 Foster, G. N. (2010). A review of the scarce and threatened Coleoptera of Great Britain Part (3): Water beetles of Great Britain. Species Status 1. Joint Nature Conservation Committee, Peterborough. Foster, G. N. & Friday, L. E. (2011). Keys to adults of the Water Beetles of Britain and Ireland (Part 1). Royal Entomological Society, Shrewsbury Foster, G. N., Bilton, D. T. & Friday, L. E. (2014). Keys to adults of the Water Beetles of Britain and Ireland (Part 2). Royal Entomological Society, Shrewsbury Savage, A. A. (1989). Adults of the British Aquatic Hemiptera Heteroptera. A key with ecological notes. Freshwater Biological Association. Scientific Publication 50. Ambleside. The Broads Authority: Wetland Conservation Reports: Smith, K., Stone, J. & Williamson, B. (2011). Broads Authority Turf Pond Surveys 2005 and data analysis 1983-2005 (pdf 2310kb). Retrieved 15 August, 2013. http://www.broads-authority.gov.uk/__data/assets/pdf_file/0020/416405/ Broads_Authority_Turf_Pond_Surveys_2005_and_data_anlysis_1983-2005.pdf Broads Authority Turf pond report 2010 conclusions (pdf 91kb). Retrieved 15 August, 2013. http://www.broads-authority.gov.uk/__data/assets/pdf_file/0004/416407/ Broads_Authority_Turf_pond_report_2010_conclusions.pdf Adrian Chalkley County Recorder, Freshwater Invertebrates 37 Brook Hall Road Boxford Suffolk CO10 5HS aquatics@sns.org.uk
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A. Chalkley A. Chalkley
Plate 8: Newly dug turf pond at Oulton Marshes. (p. 33).
Plate 9: 1-year old turf pond at Oulton Marshes. (p. 33).
A. Chalkley A. Chalkley
Plate 10: Larva of Ornate Brigadier Soldier Fly Odontomyia ornata (p. 50).
A. Chalkley
Plate 11: Larva of a purse-cased Caddis fly Agraylia sexmaculata, c. 3mm (p. 53).
Plate 12: Cased Caddis fly larva Leptocerus tineiformis (p. 53).