Wildlife Survey of
PIGEONHOUSE STREAM
AND THE MALAGO
May / August 2010
For South Bristol Riverscapes Partnership
Phil Quinn (Ecology and land use) MIEEM Flat 4, 15 Osborne Road, Clifton, Bristol, BS8 2HB. Tel. 0117 9747012; mob. 0796 2062917; email: [email protected]
Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
CONTENTS
Page
1. Summary 3-4
2. Remit 5
3. Site description 5-6
4. Methodology 7-8
5. Caveat 8
6. Results 8-40
6.1 The Malago 8-25
6.1.1 Dundry Slopes 9-13
M1 East of Strawberry Lane 9 M2 West of Strawberry Lane 10 M3 Ditch in a hedge 10 M4: A Malago is Born 10-11 M5: Teenage Malago 11-12 M6: Pretender to the Throne 12 M7: Claypiece Road isolate 12
6.1.2 Hengrove Plain and Bedminster 14-25
M8: The Stream Invisible 14 M9: Suburban Streamside 14-15 M10: Malago Valley SNCI 15-16 M10a Small tributary ditch 17 M11: A Whimper of a Watercourse 17-18 M12: Up the Junction 18 M13: Fire, Fire, Pour on Water 18-19 M14: Malago Incognito 20 M15: Parson Street to Marksbury Road 20-21 M16: Malago Vale 21-22 M17: The Bedminster Triangle 22-23 M18: Cotswold Road Canyon 23-24 M19: Water Rail 24 M20: Clarke Street dog-leg 24-25
1 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
6.2 Pigeonhouse Stream 25-40
6.2.1 Dundry Slopes 26-33
P1: Lower slopes tributary stream 26-27 P2a: Pigeonhouse Stream (headwaters) 27 P2b: Pigeonhouse Stream (tufa stream) 28 P2c: Pigeonhouse Stream (ancient woodland) 28-29 P2d: Pigeonhouse Stream (middle slopes) 29 P2e: Pigeonhouse Stream (south of pipeline crossing) 30 P2f: Pigeonhouse Stream (pipeline crossing) 30 P2g: Pigeonhouse Stream (pipeline crossing to culvert) 31 P3: Main tributary 32 P3a: Minor stream 32 P4: Upper tributary stream 33
6.2.2 Hengrove Plain 34-40
P5: Resurgence 34 P6: Hareclive Road to Fulford Road 34-35 P7: Whitchurch Lane or Bust 35-36 P8: The Hengrove Lake District 37 P9: Crox Bottom 37-38 P10: Hartcliffe Way / Pigeonhouse Stream 39-40
7. Discussion 41
7.1 General 41 7.2 Variation between May and August surveys 41
8. Recommendations 42-45
9. Conclusions 46
10. Appendices: Species records 47-61
10.1 Plant species 47-57 10.2 Fish species 58 10.3 Bird species 59-60 10.4 Mammal species 60 10.5 Invertebrate species 61
Survey maps
2 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
1. Summary
Twenty kilometres of the Malago and Pigeonhouse Stream and their tributaries were surveyed over the 20th, 21st and 23rd May 2010 with a follow-up survey on 12th August 2010. Physical access was gained to over 85% of the watercourses where they flowed in an open channel. Slightly more than 3 kilometres of watercourse were found to be culverted.
The timing of the survey not only offered an excellent opportunity to record and assess the riparian and emergent vegetation associated with the streams, it was also particularly good with regard to assessing the vegetation of the more wooded sections of stream as many species of herbaceous woodland plants are spring flowering.
The main discoveries of this survey are:
The headwater streams (on Dundry Hill) are markedly different from the main streams running across urban south Bristol and have great value in terms of nature conservation value. The main streams also have nature conservation value but have been heavily modified by human actions; their flora comprises less rare species but the range of habitat they offer is considerably more diverse than that on the headwaters.
The headwater streams are often bordered by exceptionally rich arrays of woodland floor plants, many of which are commonly known as “ancient woodland indicators”. Species of note include tutsan Hypericum androsaemum, wood vetch Vicia sylvatica, hairy wood-rush Luzula pilosa and wood spurge Euphorbia amygdaloides. Other woodland species of note include sanicle Sanicula europaea, wood millet Millium effusum, goldilocks buttercup Ranunculus auricomus, wood anemone Anemone nemorosa and sweet woodruff Galium odoratum.
The silt trap ponds on both the Malago and Pigeonhouse Stream have a good diversity of wetland plant and invertebrate species.
Imperforate St John’s-wort Hypericum maculatum, technically not an ancient woodland indicator, but found here in a woodland situation, is perhaps the rarest plant species to be recorded during the survey. It has a very restricted distribution in the Bristol region with very few records south of the River Avon.
Large fish –possibly roach Rutilus rutilus or rudd Scardinius erythrophthalamus are present in the deeper sections of Pigeonhouse Stream in Crox Bottom; bullhead Cottus gobio are relatively common under stones in the lower reaches of the Malago. Three-spined stickleback
3 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Gasterosteus aculeatus were frequent and occasionally abundant throughout often forming small shoals.
A large population of the attractive damselfly beautiful demoiselle Calopteryx virgo are present on the middle sections of the Malago and Pigeonhouse Stream, particularly in the area around their confluence.
By late summer much of the botanical interest along the streams has peaked, with only trifid bur-marigold Bidens tripartita – a late flowering locally Uncommon plant – of note. This species is present mainly in Malago Valley SNCI.
Parts of this stream system are very attractive and naturalistic –remarkably so given that much of the Malago and Pigeonhouse Stream run through a densely- populated urban area. The tributary and headwater streams on Dundry Hill are particularly notable for their wild and semi-natural conditions although most of the main stream sections to the north of Dundry Hill flow through public open space where an enlightened management regime enhances their semi-natural character.
Public access is possible through much of the course of the two streams and their tributaries; this can be either formally designated as in the parks and public open spaces or unofficial as in many of the headwater and tributary stream areas. Footpaths and cyclepaths following the course of the streams through the urban areas appear to be well-appreciated by the public. The aesthetic value provided by the mature and semi-mature streamside trees to adjacent householders as well as those members of the public using the streamside paths for walking dogs, commuting, or just out for a pleasant walk, is high.
There is a high potential with both watercourses to encourage the public to look out for notable species and also to monitor certain sections to record littering incidents (high on the agenda of many members of the public who approached the surveyor). Establishing community action groups to combat littering in the streams may well prove a way of enabling local residents to engage more fully with these diverse and attractive watercourses.
Wood spurge Euphorbia amygdaloides from the Pigeonhouse Stream headwaters
4 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
2. Remit
To undertake a wildlife survey of Pigeonhouse Stream and The Malago, and their tributaries for the South Bristol Riverscapes Project. To record all wildlife (or signs of wildlife) seen along the watercourses, including descriptions of habitats and any management currently taking place; to note any features of concern and to make brief recommendations on management if necessary. To offer an awareness of the value of the brook and its tributaries in their context of urban south Bristol. To produce a map with annotated maps detailing all relevant findings.
3. Site description
The survey area comprises two main watercourses (and numerous tributaries on Dundry Hill) which flow together to form the Malago. Although the conjoined watercourse is known as the Malago it is the other watercourse –Pigeonhouse Stream–which is generally the larger of the two.
The western stream (the Malago) rises amidst species-rich unimproved and semi-improved horse-grazed pastures, dense scrub, unmanaged species rich hedgerows, tall herb and scattered woodland on the northern slopes of Dundry Hill just to the south of the urban area of Bristol. It soon enters suburban south Bristol and experiences a great degree of culverting –effectively being lost from view for almost half its length under Withywood before emerging again in Bishopsworth until it is culverted once more until its confluence with Pigeonhouse Stream
The eastern stream (Pigeonhouse Stream) also rises amidst the diverse and species rich landscapes of the northern slopes of Dundry Hill to flow through urban south Bristol. Only small sections of its course are culverted and it generally flows with a somewhat greater volume than the Malago.
The conjoined stream, flowing north as the Malago, flows through an increasingly hard engineered landscape as it enters Bedminster with many lengths of bank comprising masonry or brickwork. Prior to its confluence with the River Avon (New Cut) the stream is culverted under them ain commercial district of Bedminster. Prior to the creation of the New Cut (1810?) the Malago flowed into what is now Bathurst Basin- one of the old docks within Bristol Harbour; here it was dammed to form a millpond, the Basin preserving the dimensions of this pond.
All the streams within this survey area rise on the steep northern slopes of Dundry Hill - a landform with a complex geology but mostly Jurassic limestones and associated strata. At the foot of the hill and extending north towards the
5 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
confluence with the Avon the streams flow across a gently undulating landscape, essentially a plain, overlying a geology of Jurassic Lias which is largely calcareous (lime rich) in nature and then an area of Triassic Keuper Marl with alternating bands of lime-rich and lime-poor substrate. The final stages of the Malago cross a geology of Carboniferous Coal Measures (that are mostly acidic sandstones). Throughout the lower (northern) half of the survey area the streams cut through a bed of alluvium (overlying the solid geology) which was deposited by the same streams several thousand years ago.
Throughout the course of these streams there are many sections that flow through parks or areas of public open space. These are frequently managed so as to enhance the nature conservation and aesthetic value of the streams. Such notable open areas include Manor Woods Local Nature Reserve in Bishopsworth, and Malago Greenway / Vale in Bedminster. Some sections of the streams run through Sites of Nature Conservation Importance (SNCIs):
Crox Bottom SNCI Pigeonhouse Stream and Adjacent meadows SNCI Malago Valley SNCI Strawberry Lane and Malago Fields SNCI East Dundry Slopes SNCI
Leaving the areas adjacent to the streams largely free of urban development has created green corridors through the south of Bristol. These corridors are essential linear networks of semi-natural vegetation that not only provide local people with a very valuable aesthetic resource (especially in areas of high density housing) but also allow otherwise very restricted species of wildlife access into a suburban landscape.
The linkage between the upland of Dundry Hill with that of the River Avon, across a wealth of landforms, geology, historic human landscapes and habitats is a significant resource for the people of south Bristol.
6 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
4. Methodology
Maps provided to the surveyor by the South Bristol Riverscapes Partnership identified those sections of watercourse which were to be targeted by this survey.
For the May surveys standard survey protocol was followed for all watercourses which were surveyed from upstream to downstream to avoid the risk of pathogens being transmitted to otherwise healthy sections of watercourse. All equipment (principally steel toed and steel plated wellington boots) were thoroughly cleaned, disinfected and dried between surveys on different sections of watercourse.
At least once every 500m of continuous watercourse a twenty metre section of stream bed would be subject to a stone turning survey whereby the surveyor would turn all large and medium-sized items on the stream bed to record any fauna living beneath them.
To avoid harm to aquatic fauna (especially those living under stones which could otherwise be crushed) the surveyor only entered the stream where necessary: e.g. where no access was available along the banks, or where it was felt that a sufficient distance had elapsed since the last entry into the stream to conduct a stone turning survey.
For the August survey there was no entry into the watercourses. Sufficient information on aquatic species had been gathered in May for there to have been no requirement to enter the streams and thereby risk crushing or disturbing organisms on the stream bed.
Notes were made on the vegetation along all sections of all lengths of watercourse. Equally all records of birds, butterflies and field signs of mammals were recorded. Notes were also made where the surveyor felt there were management or interpretative opportunities which could enhance
The physical nature of the water course was also recorded: width of channel, depth of water, whether pools or riffles or both, height and steepness of banks, nature of the substrate and general observations on water quality. Where specific concerns were noticed e.g. significant levels of littering, foul water discharge or invasive plant issues, these would also be recorded.
Throughout this report the terms “left bank” and “right bank” are used. These mean that if you are standing midstream in the watercourse, looking downstream with the water flowing away from you the left bank is on your left hand side whilst the right bank is on your right hand side.
7 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
The surveyor, Phil Quinn (MIEEM), has over twenty years experience of ecological survey -mostly in lowland southern Britain. PQ furthermore has a Natural England crayfish survey license (20101209).
Late spring 2010 was a period with very little rainfall and the preceding winter and early spring had also been drier than normal. Consequently water levels were possibly lower than might have been expected at this time of year. There was no precipitation during the survey period; dry & sunny conditions prevailed.
The August survey was undertaken during a prolonged period of changeable weather with short dry periods giving way to short periods with heavy showers. Water levels were approximately one third to one half lower than witnessed in May. During the August survey climatic conditions were cool and overcast.
5. Caveat
The results from this survey presented in this report represent the wildlife and habitats of the Pigeonhouse Stream and Malago catchment at particular seasons (late spring and late summer) in a particular year (2010). As a dynamic semi- natural system largely flowing within an urban environment there are likely to be seasonal and annual variations to faunal assemblages. Botanical assemblages may vary from year to year according to management works and woodland succession.
6. Results
The following detailed accounts of individual sections of watercourse are intended to act as reference material to assist an understanding of particular locations and to help guide potential management works by providing information on existing interest. These accounts are unlikely to make stimulating reading in their own right.
6.1 The Malago
Throughout the course of the two main confluent streams this is the smallest and has less of its course above ground; it is fed by fewer tributaries and in its upper (headwater) sections at least has a slightly lower nature conservation interest and aesthetic appeal than the headwaters of Pigeonhouse Stream. Large sections of the Malago are culverted - the section between Four Acres and Whitchurch Road; the section running through the northern quarter of Malago Valley SNCI; a section running between Hereford Street and Clarke Street (Bedminster) and the final 400 metres below the main commercial area of Bedminster until the confluence with the River Avon (New Cut).
8 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
This stream, in similar with Pigeonhouse Stream, has two distinct characters: a brisk watercourse flowing down steep wooded gullies on the northern slopes of Dundry Hill, and a more sluggish lowland section slowly cutting through the Hengrove and Bedminster plain.
The main stream and its tributaries on the upper slopes of Dundry Hill have thin bands of woodland and dense scrub along their banks; it is in some of these areas that a relatively rich woodland ground flora with species present that are often termed “ancient woodland indicators” can be found.
On the plain the bulk of the non-culverted stream has a considerably lower botanical interest with different habitats and plant communities, more homogenous and typical of lowland watercourses, present. Although botanically species-poor these communities can provide texture and colour as well as the habitat for many invertebrates -all adding interest to otherwise rather barren amenity landscapes through which much of the stream flows.
6.1.1 Dundry slopes
M1. East of Strawberry Lane
This is a small tributary stream with the lower (upstream) section comprising a steep narrow gully within a young broadleaved woodland fenced against grazing livestock (sheep) on the eastern side. The upper (downstream) section comprises a ditch within a narrow belt of mature hedgerow with access by grazing horses on the north side.
The stream within the woodland section was approximately 0.25cm wide and 2cm deep at the time of survey. There were no emergent or riparian plant species recorded here. The woodland has a canopy of semi-mature ash with a high understorey dominated by hazel; there is also some English oak, wych elm, holly, hawthorn and field maple. Bramble is abundant around the edges of the woodland, especially to the south west where a small abandoned pasture is rapidly becoming dominated by this species.
In the spring the field layer within the woodland was relatively diverse although dominated by ramsons and locally by nettle and bramble. Bluebell, wood speedwell, yellow archangel, male fern, enchanter’s nightshade, moschatel, hart’s-tongue fern and opposite-leaved golden saxifrage are all recorded though never common. Many of these species were no longer apparent in late summer and no additional notable species were present at that time.
The flora of the downstream section, where undamaged by grazing animals, is similar to that of the woodland.
9 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
M2. West of Strawberry Lane
The thin belt of species-rich woodland running along the western side of Strawberry Lane is bounded on its western side by a small ditch approximately 1.5m deep and 0.5m wide at the base. This ditch, shown as a watercourse on maps provided to the surveyor, was completely dry at the time of both surveys and had no riparian or emergent plant species associated with it. Both woody and herbaceous plant species on the edges of the ditch and within the wider woodland of which it forms part are very similar to those described for section M1 (above).
M3. Ditch in a hedge
The upper (southern) reaches of this section comprise a small dry ditch within a thick unmanaged hedgerow. The hedge is dominated by hawthorn, hazel, elder and ash with some blackthorn and guelder rose; there is also much bramble which deters horses grazing in adjacent fields from entering this hedgerow.
The lower (northern) reaches of this section have a small flow of water, little more than a narrow trickle at the time of survey, within the shallow ditch. Ivy is dominant within the field layer in the hedge although in the spring ramsons is also very common. There is some dog’s mercury, early dog violet, yellow archangel and bluebell at this time. In late summer there was little apparent botanical interest.
M4. A Malago is Born
This is the largest of the headwater streams on this section of Dundry Hill and it is identified on maps provided to the surveyor as The Malago. The stream rises to the south of (above) Oxleaze Lane as a convergence of three small watercourses which unite on the southern edge of the road. The combined flow then enters a steep earth gully with sheer 4m high banks. The channel width in May was approximately 1m although the width of the stream at the time of survey was approximately 0.5m and its depth averaged 4cm. In August the width of the stream was 25cm with an average depth of 10cm.
The gully supports a thin band of mature scrub / young deciduous woodland which is partly open to horses on the eastern side but more securely fenced on the western side. Hazel is the dominant woody species here with field maple and ash occasional; bramble is locally abundant. Ivy is the commonest field layer species here although in the spring cow parsley can be frequent; patches of ramsons, bluebell, male fern, wood speedwell and dog’s mercury are also common especially where horses do not have access.
The lower (northern) reaches of this section flow through a much more shallow channel where the banks are often between 1 and 1.5m high and the stream, in
10 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
May, between 0.25 and 0.5m wide with a depth still of approximately 4cm. In late summer the flow and width of the stream had decreased on one third to one half. In this lower section there are a few small rocks embedded in the stream bed as well as some small patches of gravel.
In the spring the lower section has a slightly more diverse flora with wood sedge, primrose, pignut, wood anemone and wood sorrel all present to varying degrees along with the field layer species described above. Ramsons and dog’s mercury are increasingly common to the north. In late summer there is little botanical interest here.
There are no emergent or riparian species here with the exception of a small quantity of pendulous sedge.
M5. Teenage Malago
The Malago here enters another gully feature with sheer 1m high earth banks alternating with 2m high sheer sides within a steep sided v-shaped narrow valley clothed in young broadleaved woodland. The width of the stream averaged 0.5m and its depth was generally 3-4cm at the time of the May survey but was reduced, in all dimensions, by one third at the august survey. There are occasional small rocks and areas of gravel within the otherwise silty channel.
Ash and hazel are the most frequent woody species recorded here but English elm, wych elm, field maple and hawthorn are also common along with an occasional mature horse chestnut. Crack willow and dogwood become more frequent to the north where the gradient is less pronounced. In the spring ramsons dominates the field layer and ivy is locally abundant here but there is also some dog’s mercury, yellow archangel, wood speedwell, bluebell, wood sedge and wood anemone.
Pendulous sedge can be locally common towards the east of this section and there are areas, where the gradient is shallow, that brooklime, fools’ watercress and great willowherb are recorded on the streamside.
The lower reaches of this section include a length of culverted stream where thin belts of planted broadleaved woodland with self-sown scrub are present over the course of the culvert. Mown amenity grassland abuts this culverted sections to the south.
Emerging from the culvert to the east of The Ridings the Malago the stream flows through a relatively shallow small v-shaped valley although the channel itself comprises a 0.75m wide stream bed comprising mostly of silt with some small stones and gravel and 2m high steep earth banks. The stream averaged a depth of 4cm at the time of May survey but less than 2cm in August.
11 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
There are occasional mature English oak and crack willow here along with much semi-mature ash (often as poles from large coppice stools), goat willow and some grey poplar; sycamore becomes increasingly common downstream. Hazel is very common in the understorey and there is also frequent hawthorn; wych elm, English elm and dogwood are also occasional.
Nettle, ivy and lesser celandine are common although ramsons tends to dominate the field layer in the spring where children have not worn large paths of bare ground. Dog’s mercury is occasional.
M6. Pretender to the Throne
Just before the Malago of section M5 leaves the steeper gradients this main tributary flows into it. In many ways it is very similar to that part of section M5 into which it flows in both nature of the stream, its channel and the woodland surrounding it. The main difference is that the stream of section M6 has a number of small 1 m high waterfalls along its course.
M7 Claypiece Road isolate
This small stream flows over a steep gradient down the north slope of Dundry Hill and is culverted just south of Claypiece Road. Throughout its short course the stream was hardly more than a thin trickle of water (with an occasional 3cm deep pool) within a 0.75cm bed in may and a scarcely perceptible thin trickle in August. The banks are generally steep earth cliffs up to 1.5m high. There is much evidence of children sing this area –worn paths and a fair amount of plastic debris. Horses graze the field to the west whilst the field to the east had recently been burnt prior to the survey; it would appear that this burnt field was previously dense bramble and bracken – both species were regenerating strongly.
A wide band of broadleaved woodland is present either side of the stream where sycamore and ash are dominant in the canopy along with the occasional mature ash. Hazel is very common in the understorey along with hawthorn whilst elder, holly, goat willow and guelder rose are also present.
The spring ground flora is rich –arguably the richest of all the headwaters of the Malago proper (but not quite as rich as many of the Pigeonhouse Stream headwaters). Whilst ramsons and ivy are locally common and occasionally dominant there is much bluebell, primrose, moschatel, bugle, pignut, yellow archangel, and occasional tutsan, early dog violet, wood sedge, wood anemone, three-veined sandwort and male fern. Of particular note however is a small population of the locally rare imperforate St John’s-wort Hypericum maculatum. In late summer the ground flora is poor.
12 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Typical Malago headwater stream with an abundance of ramsons Allium ursinum
Woodland mammals are elusive, frequently dangerous and must be approached with caution
13 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
6.1.2 Hengrove Plain
There is a considerable diversity of structure here with regard to plant communities and management; there has also been a significant canalisation of part of stream as it flows through the Malago Valley SNCI.
M8. The Stream Invisible
Small lengths of the Malago are indicated on the survey maps as unculverted as it runs through parts of Withywood. However these areas could not be physically accessed.
A larger section of the stream flows to the west of a depot east of Whitchurch Road on the southern edge of Bishopsworth. This could not be physically accessed however there was limited visual access to the northernmost 10m of this section as it flowed towards Headley Road. Here there is much masonry and concrete hard-engineering of both banks as well as sections of stream bed with some young English elm and elder on the bank tops along with small quantities of nettle, cow parsley, goosegrass, herb robert and some pendulous sedge.
There was a distinct smell of effluent from this section at the time of both surveys.
M9. Suburban Streamside
Between Headley Road and St Peter’s Rise there are two small sections of the Malago that allow visual access.
The southern section runs parallel to the eastern side of Avon Road and there is a mesh fence covered with wild clematis and bramble between the stream and Avon Road; hedges and fences of the edge of a residential property mark the eastern boundary.
The stream here runs within a relatively deep ( 2.5- 3m) and wide (up to 2.5m) channel which held 20cm of water on its gravel and sand bed in May but approximately 12cm in August. There are some large ash on the bank tops along with occasional hawthorn, blackthorn and elder.
North of Hillyfield Road the stream banks are strengthened with gabions and concrete for a distance of some 10m downstream from the road bridge. From this point on hard-engineered banks predominate although there also appear to be natural earth banks -visual access was limited through much of this section due to the stream flowing between back gardens and out of view to the surveyor.
14 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
In those sections of stream visible for survey there were a large number of small and mid-size stones and rubble within the 3m wide channel which was up to 0.5cm deep in places at the time of the spring survey and 0.25cm deep in late summer. Semi mature trees are frequent on the banks here –ash, lilac, hawthorn, English elm, buddleia and blackthorn were all recorded here. The ground flora is generally impoverished with ivy, goosegrass and bramble being the predominant species.
M10. Malago Valley SNCI
For its entire length through this site the Malago has the ancient woodland of Manor Wood on its right bank. The left bank is open to the amenity grassland and blocks of scrub characteristic of the rest of the Malago Valley SNCI.
In May, upon its emergence from the culvert taking it under St Peter’s Rise, the stream was 7m wide and up to 1m in depth and has many rocks and much rubble in its bed. However these dimensions soon narrow to a 4m wide channel with a braided and shallow flow of pools and riffles with the pools averaging 0.5m in depth and the rifles averaging 5cm deep. In August these figures had reduced by approximately one half. Rocks and rubble continue to be frequent on the stream bed but increasingly less so as the stream progresses northeast. The channel is mostly about 1.5m deep with steep earth banks although there are lower and more gentle banksides, usually the inner curves of meanders.
Approximately 80m downstream of the stream’s resurgence there is a small concrete stepping stone weir which local people use to access Manor Wood from the area of amenity grassland. Immediately below this weir is a 1m deep plunge pool. There are other informal children’s trails across narrow and shallow sections of the stream.
For most of its course through this section the Malago has woodland plant species on its right bank: mature ash and English oak are the main canopy species along with some sycamore; some large crack willow and occasional alder are also present along the stream. The understorey is mostly hazel, hawthorn and field maple with some holly, blackthorn and dogwood. In spring ramsons is dominant in the field layer along with ivy. Along the streamside there is much pendulous sedge, some watercress, fool’s watercress, brooklime and hemlock water-dropwort; tutsan –an unusual plant associated with semi-natural ancient woodland is also present in small quantity.
On the left bank there are occasional blocks of scrub but this bank mostly supports thin bands of tall herb vegetation. On two right bank meander bends there are large populations of the locally uncommon plant butterbur; these have very distinctive large leaves and thrive in the open conditions where tree and shrub growth are not too shading. Himalayan balsam is occasional here too.
15 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
The stream’s flow slackens as it nears a heavily silted silt trap pond. Here there is a wide but shallow channel running close to the left bank but the majority of this pool comprises a large bed of silt with much cow parsley, great read-mace, great willowherb and branched bur-reed. Some amphibious bistort Persicaria amphibia is present here. Moorhen were present amongst the tall herb vegetation here and it is likely they may be breeding.
The silt trap pond is formed by a small concrete dam blocking the stream course; this was constructed in the mid 1970s as part of flood prevention works. The dam has a small flow of water over its spillway; this spillway soon leads into a concrete lined channel (with angled concrete banks) which leads into a large metal grated culvert, again part of the 1976 flood prevention scheme. This section below the dam has some semi-mature trees and scrub as well as tall herb vegetation in the more open areas.
Downstream of the silt pond and on the left bank are several large patches of a knotweed species (exact identification not known). This species did not key out satisfactorily to any known species or hybrid of Fallopia or Persicaria. It is highly likely to be of garden origin
Trifid bur-marigold Bidens tripartita was recorded in August from the left bank ledge just upstream from the culvert grille in great abundance; also present here were the bird seed alien white millet Echinochloa frumentacea and numbers of potato plants Solanum tuberosum. There was also an unidentified alien plant which appeared to have been a species of thistle although no flowers were present at the time of survey.
After the culvert entrance the stream is channelled underground for approximately 300m.
16 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
The silt trap pond within the Malago Valley SNCI
M10a Small tributary ditch
Half way along section M10 there is a very small stream flowing into the left bank of the Malago. This stream rises some fifty metres upslope amidst dense mature scrub and flows within a shallow 1m wide ditch which has a quantity of small stones and rotting timber within it. The scrub is mostly sycamore, elder, hawthorn and hazel. The ground flora is patchy under the dense shade but in the spring ramsons is locally common and there is also some bluebell, yellow archangel, dog’s mercury, wood sedge and a single plant of tutsan. In late summer there was no botanical interest here.
M11. A Whimper of a Watercourse
This is the lower section of the Malago before it flows into Pigeonhouse Stream and after its emergence from a 300m length of culvert. The upstream section has some hard engineered banks and there are also areas where the stream bed is of concrete. The flow was remarkably feeble at the time of survey, especially given the relatively strong flow witnessed in the upstream sections of the Malago before the stream entered the culvert. At the time of the May survey the depth of water averaged 3-4 cm and the channel width was approximately 2m. By August this flow was reduced by approximately one third.
Fencing associated with adjacent commercial premises is hard upon the 1.5m high steep earth bank tops and the whole section is rather shady due to the
17 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
presence of semi-mature trees and shrubs: cherry, sycamore and alder as well as much bramble.
The downstream section (after flowing under Hartcliffe Way) has a 4m length of hard-engineered bank on both sides of the stream and then 1.5m high steep earth banks. This whole lower section lies within dense scrub growth and ground layer species diversity is low with ivy the main species present.
In May two female beautiful demoiselle were recorded on bramble in full sun the western side of the Hartcliffe Way bridge.
M12. Up the Junction
To the north of the horse grazed fields adjacent to section 10 of Pigeonhouse Stream there is an area which is fenced off from livestock on the left bank; here an attractive open scrub woodland with much tall herb and tall grass vegetation has developed. This was particularly good for invertebrates at the time of survey. On the right bank there is palisade fence around part of an adjacent depot with dense scrub between the fence and the stream.
It is within the dense scrub on the right bank of this southern end of section B7 that the very small inflow of the Malago forms a confluence with Pigeonhouse Stream. The Malago here contributes only a very small, almost stagnant flow. Pigeonhouse Stream flows within a 1.5m wide channel through section B7 with steep 1.5m high earth banks.
North of the Malago confluence there are a number of commercial and institutional premises on the right side of the stream. These include the Sita / Suez amenity depot, the Saint-Gobain glass complex, and Bedminster Fire Station. Three vehicle access bridges cross the stream here and each is associated with sections of stream that have had trees and shrubby vegetation controlled to the encouragement of emergent and riparian herbaceous species. In between these open areas there are sections of stream where dense scrub is present on both banks. Subsequently there is a significant structural diversity here which will encourage a diverse wildlife interest: many beautiful demoiselle were recorded here at the time of the May survey. In August this section was heavily shaded with much shrub growth.
M13. Fire, Fire, Pour on Water
The section of stream which flows to the west of the Fire Station has a few semi- mature ash, alder and hawthorn as well as some areas of bramble but is mostly free of scrub and subsequently has an excellent suite of tall herb, emergent and herbaceous riparian plant communities, especially on the left bank. These could
18 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
not be physically accessed for survey but it was apparent that there is an abundance of hemlock water-dropwort, great willowherb, hemp agrimony, branched bur-reed and common reed. In May many beautiful demoiselle were recorded here and there were many sticklebacks observed within the stream.
The Malago by Bedminster Fire Station –excellent invertebrate habitat
19 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
A male beautiful demoiselle Calopteryx virgo
M14. Malago Incognito
Downstream from the Fire Station the Malago flows through land with no survey access and no visual access. Subsequently there is no description of this section.
M15. Parson Street to Marksbury Road
Running through a public open space this is the first length to offer visual and physical survey access after the elusive stream of section M13. Both banks of the southern third of this section are hard-engineered: stone revetment on the right bank and a mortared masonry wall on the left bank; both banks are approximately 3m high. A tarmac path runs on top of the left bank wall and leads to an area of garages and back gardens; there are some mature elder growing on the wall but generally this section of bank is largely free of vegetation. The hard-engineered right bank is covered with herbaceous vegetation –mostly tall herbs such as cow parsley and nettle with much bramble and false oat-grass. Running parallel with the east bank is a cyclepath / footpath.
The stream bed is approximately 2-3m wide here and silty with some mid-sized stones and rubble; there is a notable silt side bar at the base of the right bank immediately north of the Parson Street bridge where fool’s watercress, common water-plantain and hemlock water-dropwort are present.
The remainder of this section comprises largely earth banks ranging from gently angled to steep (between 1 and 3m high) largely covered with luxuriant grasses
20 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
and tall herb vegetation. On the right bank this vegetation is present in a largely uninterrupted 2-5m wide band with occasional semi-mature ash, crack willow, white willow and hawthorn.
Along the edge of the stream there is an abundance of emergent and riparian vegetation with fool’s watercress, hemlock water-dropwort, great willowherb, flag iris, branched bur-reed, great sweet-grass as well as occasional specimens of the uncommon water dock –a species more usually found on the Somerset Levels.
Towards the northern end of this section there is some hard-engineered right bank set back two metres from the edge of the stream; between this engineered bank and the stream is a silty floodplain with emergent and riparian plant species. Also recorded here is a population of an invasive alien plant: floating pennywort Hydrocotyle ranunculoides. Curled pondweed, a native plant, is present in scattered locations throughout this section. Bullheads and three- spined sticklebacks were recorded here in May.
At the northern limit of this section, for 10 metres upstream from Marksbury Road bridge, the banks are hard-engineered with masonry but the bank tops are still lushly vegetated with tall herbs and grasses. On the right bank here there is a silty 2m wide ledge where a good range of tall herbs and riparian plants are recorded.
The open and luxuriant vegetation alongside the stream here supported a large number and diversity of invertebrates including (in May) several beautiful demoiselle. Section M15 is one of the most semi-natural and diverse sections of stream throughout the entire survey area.
M16: Malago Vale
Immediately north of the Marksbury Road bridge is a 20m section of semi-mature dense scrub forming part of the boundaries of adjacent houses. The left bank is hard-engineered here for a length of approximately 15m but the right bank comprises a gentle silty bank with some hemlock water-dropwort and great willowherb. The stream is 1.5m wide and was approximately 10cm deep here at the time of the May survey but these dimensions had decreased to 0.6m wide and 6cm deep in August..
Downstream the stream flows on the western edge of the Malago Vale public open space, the channel was 1.5m wide and some 8-10cm deep in May but 0.8m wide and approximately 5cm deep in August. The left bank comprises a 0.5m high steep earth cliff grading into a gentle slope up to a tall mesh fence which marks the edge of an industrial site. Between the stream and the fence is a 3m wide area with scattered mature scrub –mainly hawthorn, elder, blackthorn and
21 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
hazel and areas of bare ground with a localised dominance of ivy. Immediately east of the fence there is line of mature Leyland cypress which cast considerable shade over the stream and its banks.
On the right bank, opposite the cypresses and the mesh fence there is an area of strimmed vegetation associated with timbered terracing and a timbered bank; this is presumably an educational resource allowing children safe access to the stream side for pond dipping. The plant community here was very poor however on the left bank hemlock water-dropwort and pendulous sedge are common immediately adjacent to the stream; curled pondweed is occasional here.
To the north of the timber terraced area the banks are more natural, comprising earth and with relatively gentle 45 degree slopes down to the watercourse where the 1.5m wide watercourse has much mid-sized rubble and stone within it and the depth of water was approximately 10cm at the time of the May survey. In August the watercourse was approximately 1m wide and some 6cm deep. The line of cypress trees with associated fencing continues on the left bank but on both banks there is also much mature scrub –typically hazel, hawthorn and blackthorn with occasional mature crack willow. The right bank has much bare ground beneath the scrub.
A foot /cycle bridge crosses the stream some thirty metres south of Bedminster Road bridge. North of this there is some hard engineering associated with a culvert outlet on the right bank, the outflow from this culvert is approximately half that of the main stream. There is also some semi-derelict mesh fencing on the right bank and some recent clearance of elder and buddleia. Scattered bushes of elder, buddleia and hawthorn as well as occasional mature poplars are present on both banks. Tall herbs (including some Russian comfrey) and rank grasses predominate on both banks but 2-3m wide silt ledges alongside both banks support dense riparian and emergent vegetation; occasional clumps of ramsons are present on the right bank. In May the stream is approximately 1.5m wide at this point and had a depth of 10cm; however by August these dimensions had changed to 1m wide and 7cm deep.
M17. The Bedminster Triangle
Emerging from under the Bedminster Road bridge there is some hard engineering associated with the bridge; Adria bellflower and wall-rue grow sparsely on this masonry. More hard engineering occurs on the downstream half of the right bank where concrete and masonry form the support for a section of St John’s Lane. A foul water discharge culvert emitting an unpleasant milky-grey fluid at the time of both May and August surveys is also present in this right bank area of hard-engineering.
22 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
The remaining areas of bank are of earth and comprise relatively steep slopes supporting mature and semi-mature trees and shrubs such as Lombardy poplar, ash, sycamore, crack willow, hazel, hawthorn, English oak and elder –all of which cause dense shading over approximately half of this section. Bramble is locally common whilst ramsons, nettle, ivy and goosegrass are abundant. Hemlock water-dropwort, reed canary-grass and pendulous sedge are occasional on the streamside. Curled pondweed is occasional within the channel.
In May the channel was 2-3m wide here and depth of water was approximately 10cm deep, however in August this had decreased slightly to 2m wide and approximately 7cm deep. Most of the stream bed is silt but there are some areas of rubble and stone; a small island of silt is present towards the right bank and this supports a limited tall herb and riparian flora.
The stream flows under St John’s Road where it is culverted for approximately 30m. However a small section of the Malago emerges from under the St John’s Road culvert where a square brick-lined open-air sluice chamber is located. This chamber is surrounded by metal railings and within the area enclosed by these railings there is a sparse flora of species typical of disturbed ground such as thale cress, perennial wall-rocket, prickly lettuce and barren brome with a few young specimens of buddleia and ash and occasional hemp agrimony. Within the chamber itself there is much silt and occasional plants of hemlock water- dropwort, common water-plantain and a horse chestnut seedling.
M18. Cotswold Road Canyon
Throughout this section the left bank is almost entirely hard engineered (vertical and 4-5m high) whilst only the southern half of the right bank is hard engineered. The non-hard-engineered sections comprise steep earth and rubble slopes running down from the back gardens of houses along Cotswold Road. Railings and some sections of masonry wall run the whole length of the left bank top as a tarmac footpath runs on the bank top parallel to the stream.
This section is very shaded as there are many mature and semi-mature trees on both banks – ash, sycamore, crack willow, hawthorn, hazel, dogwood species and elder along with some bramble, lilac and garden privet. Ivy predominates in the ground flora and there is only an occasional presence of streamside species such as hemlock water-dropwort and pendulous sedge. Rustyback fern is locally common on the masonry wall atop the left bank, young specimens of buddleia and some Guernsey fleabane grow here too. Occasional small clumps of ramsons are present on the right bank slope, along with some herb benet, false oat-grass,
23 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
In May the channel was 2-2.5m wide throughout but with only 5-10 cm of water over the largely silty bed. In August channel width had reduced to 1.5m and water depth averaged approximately 5-6cm.
In the northern quarter of this section the footpath crosses the stream and there is a more luxuriant tall herb community on the left bank which forms part of the base of the adjacent railway embankment. Japanese knotweed –a pernicious alien plant is found here. On the right banks there is a thin strip of relatively dense shrubs associated with railings; Virginia creeper is very common here.
M19. Water Rail
Emerging from a section of culvert under the railway line there is no physical access to this section of the Malago. The embankment of the railway line forms the right bank whilst the left bank, 2-3m in height and a steep slope of approximately 70 degrees, appears to have been partially re-profiled as part of the clearance works on a former industrial site which previously abutted the stream. In May there was no physical access and only limited visual access however in August several sections of hoarding that screened the site had been ripped down thus allowing close access. The site of the industrial unit comprised a loose hardcore substrate with an ephemeral /short perennial and scattered tall herb plant community where prickly lettuce, Canadian goldenrod, herb robert, fescue grasses and black medick were most frequent. The right ban is hard engineered with only a small quantity of vegetation –typically water-cress, common couch and great willowherb in isolated silty pocket. There is some coppiced sycamore and a relatively dense tall herb community on the left bank where nettle, Russian comfrey, hemp agrimony, mugwort, broad-leaved dock, spear thistle and hogweed are particularly prominent..
M20. Clarke Street dog-leg
This is the final section of surveyed stream; to the north the Malago is culverted and hidden from view until it emerges from its culvert in the bank of the River Avon (New Cut).
This section flows entirely within a brick and concrete lined channel; there are no sections of bank which are not hard-engineered. The bed has much small and mid-sized rubble and there are also occasional silt side bars where small quantities of emergent and riparian vegetation grow: hemlock water-dropwort, bittersweet, fool’s watercress and hemp agrimony; occasional clumps of water- starwort are also present in the watercourse which was 2-2.5m wide 4-10cm deep in May and 2m wide and approximately 5cm deep in August. The upper sections of the brick walls support a sparse flora of young buddleia, thale cress, Guernsey fleabane, perennial wall-rocket, herb benet, red valerian, lamb’s
24 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
lettuce, goosegrass, garlic mustard, common ragwort, Oxford ragwort, ivy-leaved toadflax and wall rue.
Old sluice on the Clarke Lane dog-leg
6.2 Pigeonhouse Stream
Throughout the course of the two main confluent streams this is the largest and has more of its course above ground; it is fed by more tributaries and has arguably the greater nature conservation interest and aesthetic appeal.
As with the Malago this stream has two distinct characters: a brisk watercourse flowing down steep wooded gullies on the northern slopes of Dundry Hill, and a more sluggish lowland section slowly cutting through the Hengrove and Bedminster plain.
The key feature of the stream and its tributaries on the upper slopes is the very rich woodland ground flora with species present that are often termed “ancient woodland indicators”. These can provide stunning displays of colour in spring and early summer, especially so when large sheets of bluebells are found.
On the plain there is a much reduced botanical interest but different habitats and plant communities, typical of lowland watercourses, are present. These can provide texture and colour as well as the habitat for many invertebrates -all adding interest to an otherwise rather barren amenity landscape through which much of the stream flows.
25 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
6.2.1 Dundry Slopes
There are many small streams and seepages on the north slopes of Dundry Hill, many of them ultimately contributing to the flow of Pigeonhouse Stream. To have surveyed and recorded all of them would have taken a considerable amount of time and other resources, so only those indicated on maps provided to the surveyor were subject to the survey.
The main focus is Pigeonhouse Stream itself. However as it displays several distinct characters over its course on Dundry the description of it is here divided into seven sections, each of which is distinctly different.
Typical Pigeonhouse Stream headwaters ground flora: bluebell Hyacinthoides non-scripta and sweet woodruff Galium odoratum
P1. Lower slopes tributary stream
This small tributary stream flows into Pigeonhouse stream just south of the grated culvert which takes the watercourse under Bishport Avenue. For much of its lower course it flows through dense scrub where hawthorn, blackthorn, elder, dogwood, bramble and young English oak and ash trees are common. Wych elm, crack willow, wild cherry and wild privet are also present here. Ivy is abundant in the field layer along the banks of this lower reach but spring-
26 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
flowering ancient woodland species such as bluebell and yellow archangel appear to be colonising here.
Further upstream there are areas where the scrub is more mature and open, thus allowing for greater infiltration of light. Here there is a more diverse woodland ground flora with wood vetch being particularly notable. Wood sedge, yellow archangel, bluebell, wood anemone, wood speedwell and dog’s mercury –all typical field layer species of established or ancient woodland –were present but never in abundance during the May survey.
In May and where sufficient light allows there is a riparian plant community with great willowherb, cuckoo flower, figwort, pendulous sedge, wild angelica, opposite-leaved golden saxifrage, hemlock water-dropwort and fool’s watercress. In August dense shading from bankside scrub significantly lowers the botanical interest here.
The stream is very small, basically a thin smear of water flowing over a earth channel bed 0.25m wide in a 0.5m deep incised channel. This channel enters a valley form to the southeast which is vegetated with dense scrub and developing broadleaved woodland. The stream emerges from a seepage with a slight tufa element to it.
P2a Pigeonhouse Stream (headwaters)
The stream rises at a spring (ST581666) on the junction between the flat fields on the summit of Dundry Hill and the lip of the steep north facing hill slopes. This is a tufa spring and it has been enhanced by the construction of rough rubble masonry walling and subtle artworks as part of a community artworks project (completed 199?).
The spring had a reputation for its waters being used in the cure of eye disorders: it was “good for the eyes”. This is almost invariably an indicator that it was formerly considered a holy well; the connection with eyesight is obscure but is widely thought to be a vestige of some rite or superstition that was associated with sacred waters.
Around the spring are semi-mature hazel, ash, English elm, field maple and hawthorn; there is much dog’s mercury and some bluebell here too along with large quantities of tall herbs such as cow parsley and nettle.
27 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
The Pigeonhouse Stream headwater spring, with tufa being deposited in-channel
P2b. Pigeonhouse Stream (tufa stream)
Flowing through an area of planted broadleaved woodland (circa ten to fifteen years old) and dense nettle and bramble growth the stream deposits a considerable amount of precipitated calcium carbonate minerals. A smaller tufa spring rises here and flows into the main channel which is shallow and not cut into the hillside. The flow of water is mostly less than 2cm deep and 0.30m wide.
Emerging into a small open area the stream pools in ruts formed by motorbikes and there is a flora typical of streams in the south Bristol area: brooklime, great willowherb, water mint, hard rush and fool’s water-cress. Great horsetail is locally abundant here in the spring but completely dominant by August.
P2c. Pigeonhouse Stream (ancient woodland)
Flowing northeast the stream enters a block of dense scrub (predominantly bramble and hawthorn) with much nettle. This forms the edge of an area of very attractive broadleaved woodland that has a very rich springtime ground flora of ancient woodland indicators. Bluebell is dominant here although dog’s mercury, wood anemone and sweet woodruff can be locally abundant. Sanicle, pignut, moschatel and yellow archangel are also common; early dog violet, wood millet and goldilocks buttercup are also present but infrequent. Only one small clump of ramsons was recorded.
28 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Ash and English oak are the predominant canopy trees, with several large specimens, although sycamore is also present. Hazel, hawthorn, blackthorn, field maple, elder, and dogwood form the understorey.
The stream here is deeply incised into a narrow gully for most of its course with a bed never in excess of 0.5m and a banktop to banktop width of approximately 1.5-2m. The banks and bed are of soil. In May the stream was rarely in excess of 2cm deep and possessed few definite pool and riffle features however by august there was scarcely any water present.
Three smaller deeply incised channels flow into the main channel within this woodland area; all but one were dry at the time of survey. The one tributary stream with water is very similar in character to the main channel but had a much smaller flow rate.
Rank abandoned pastures with considerable amounts of tall herb and scattered scrub vegetation (predominantly bramble) surround this area on most sides and the boundaries are largely diffuse with only relict post and wire fencing in places.
There is a children’s rope swing off one of the larger oaks in this wood, around this feature there is much bare ground and also some plastic and metal litter.
P2d. Pigeonhouse Stream (middle slopes)
Emerging from the ancient woodland the stream in May had an average depth of 2cm and was mostly a film of water flowing over an earth bed 0.20m wide; in August the depth averaged 1cm. There are several small falls (less than a metre in height) and the channel comprises a series of very tight meanders cut some 1.5 deep although there are also some areas where the stream flows over a relatively flat surface not cut into the soil.
Grazing livestock on the north (left) bank have access to this side of the stream which has post and wire fencing. The livestock keep the bankside scrub open and cause the woodland ground flora to be poached and limited to small blocks associated with tree roots or steep areas of stream bank. The south (right) bank is not grazed and here the scrub is tall and dense and the spring ground flora rich with some greater stitchwort as well as much bluebell, yellow archangel and other species typical of the more botanically notable sections of headwater stream.
29 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
P2e. Pigeonhouse Stream (south of pipeline crossing)
Until the small area of cleared streamside, where recent pipeline works cause a significant break in continuity, the stream flows within a narrow and steep sided valley with mature scrub and broadleaved woodland on both banks. The channel is often incised deep, frequently in excess of 3m although the stream bed width in May rarely exceeded 1m and in August less than 0.5m. Water depth at the time of the May survey was mostly less than 5cm although there were occasional shallow pools with depths of 10cm. In August the average depth was between 2cm and 3cm. A few small stones are present in the bed of the stream.
Notable spring ground flora species such as wood anemone, bluebell, yellow archangel and sweet woodruff are locally common here but this stretch of streamside is less densely packed with ancient woodland ground flora than sections upstream and downstream. This may reflect a more recent woodland colonisation event here than along other sections; some post and wire fencing is present on both banks. The wooded banks are fringed by dense banks of bramble and the adjacent fields grazed by horses.
A footbridge crosses the stream approximately half way along this section; either side of it there is a considerable amount of metal and plastic debris which has been dumped here. A small dry side valley joins the stream from the north (left) bank at this point.
P2f. Pigeonhouse Stream (pipeline crossing)
A 10m wide swathe of streambank habitat has recently been cleared to allow a pipeline to be laid. This pipeline crosses under the stream and some vegetation has recolonised; there is no shrubby growth here mostly just common herbaceous plants associated with disturbed damp ground such as creeping buttercup, docks, great willowherb and silverweed; on the stream edge there is brooklime, floating sweet-grass, hard rush and pendulous sedge. On the banks there are some woodland species such as wood vetch, thin-spiked wood sedge, greater stitchwort, dog’s mercury and grey sedge.
A number of large rocks lies in the stream and on its banks; these were presumably placed here after the pipeline works finished to help stabilise the bank and channel and reduce the risks of erosion. The stream here is approximately 1m wide and with a maximum depth in may was 10cm but in August was 5cm; the banks are less than 1m high. Post and rail fencing against the adjacent fields is present 8-10m from the stream on both sides
30 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
P2g. Pigeonhouse Stream (pipeline crossing to culvert)
Enlarged by two tributary streams (see 4 and 8) the main watercourse here flows through a landscape with gentler gradients than upstream sections and the flow is slightly less brisk than witnessed before. The channel bed is typically 1m wide and the banks between 0.5m and 3m deep -the deeper sections being gully-like; the whole watercourse lying within a small valley with sides of approximately 30- 40 degrees although in some downstream sections there is a 3m wide floodplain in places. Some areas of gravel and occasional small to mid size stones are present within and adjacent to the streambed; a more developed series of pools and riffles is apparent here although water depth never exceeded 10cm at the time of the May survey and no more than 6cm in August.
Throughout this section the bankside vegetation is typically that of mature scrub developing into broadleaved woodland. A number of veteran English oak and ash are present here, although unfortunately most are much damaged by arson and attempted felling / partial ring barking. Mature hazel and hawthorn are dominant in the understorey which also includes field maple, dogwood, guelder rose, grey willow, blackthorn and locally abundant bramble.
The springtime field layer is occasionally very rich although it becomes progressively impoverished downstream. An exceptional area of ancient woodland ground flora, covering no more than 4 square metres, is found on the north (left) bank at ST586671. Here there is a dense area of sweet woodruff, wood vetch, thin-spiked wood sedge, wood millet, hairy St John’s-wort, bluebell, yellow archangel, hairy wood-rush, wood spurge (the only recorded location for this species during the survey), primrose, dog’s mercury, moschatel, common valerian and wild strawberry. This location is also where there is a great deal of erosion occasioned by children; this exceptional flora is threatened by this activity and indeed its historic area may have been reduced by the impact of children’s activities. During the August survey it was apparent that several small fires had been started on some of the remaining areas of species-rich vegetation. The long-term survival of this, the most species-rich section throughout the whole survey area, is in doubt.
Many desire lines run through the woodland and along the banks of the stream here, and it is presumed that many were created by children. A small foul water outlet culvert empties into the left bank of the stream of this section
The stream flows into a grated culvert approximately 60m south of Bishport Avenue. Above the culvert there is dense bramble scrub and pockets of relict rank neutral grassland where species such as black knapweed and glaucous sedge are found.
31 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
P3. Main tributary
Flowing from the southeast of Pigeonhouse Stream is a small stream which forms the main tributary on the Dundry north slopes. It flows into Pigeonhouse Stream just south of the pipeline crossing and in many respects is a smaller version of the upper reaches of Pigeonhouse Stream proper. Flowing mostly within a tight earth gully 1-2m wide at the base and 4m high with a bank top to bank top width of approximately 4m. There are very few stones of any size in the stream bed and the stream itself was between 0.75m and 1m wide at the time of the May survey with an average depth of approximately 3cm. In August these dimensions were halved.
Upstream the valley is slightly wider and there are fewer gully sections. Many rusting hulks of stolen and burnt cars (which were rolled down the hill by the thieves /arsonists –particularly during the mid- late 1990s) lie within the course of the stream. These have quickly been overwhelmed by silt, are rusting with considerable speed and are being enveloped by vegetation -in particular bramble.
The predominant vegetation along the banks of this stream is a semi-mature broadleaved woodland with dense scrub (mainly bramble) on the outer edges where the woodland meets grazed pasture. Species composition of both canopy, understorey and field layer is very similar to that of the Pigeonhouse Stream in that it is diverse and rich in many ancient woodland early summer species: wood anemone, wood millet, wood speedwell, sweet woodruff, sanicle, bluebell, moschatel and yellow archangel. There are several very large English oaks and ash and the stream is occasionally very shaded and enclosed by dense shrub growth; in these areas ivy is the dominant ground flora species.
P3a. Minor stream
This small stream is approximately 0.35m wide and in May had a thin smear of water 2-3cm deep running within its bed flowing within a 1.5m wide and 1-2m deep earth gully. In August there was no water present. The headwaters are essentially a collection of tufa seepages flowing together to form the stream.
Dense scrub covers much of the banks and extends to form a small block of woodland enveloping a number of the tufa seepages. The ground flora is of some interest with many of the ancient woodland indicator species but they are limited to within 2m of the edge of the stream and are only recently colonising the scrub. Large ash and English oak are frequent here.
32 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
P4. Upper tributary stream
A small tributary flows into Pigeonhouse Stream from the south east roughly halfway up the hill slope. Most of its course runs through broadleaved woodland which has developed from mature scrub and in May there were bluebell, wood speedwell, yellow archangel and some sweet woodruff amongst other woodland plants. A minor sub-tributary flows in a shallow channel where hard rush, water mint, angelica, meadowsweet brooklime and hemp agrimony grow. The ground flora was impoverished in August. Two small dry gullies, running through the developing broadleaved woodland, lead into the main stream from the south west.
The distinctive stipules of wood vetch Vicia sylvatica, a locally scarce woodland plant recorded in sections P1, P2f & P2g
33 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
6.2.2 Hengrove Plain
This section comprises the stream as it flows over the relatively flat landscape of Hartcliffe, Hengrove and Headley Park until the confluence with the Malago.
P5. Resurgence
Pigeonhouse Stream has been culverted for approximately 250 metres under Bishport Avenue. It emerges from a metal grilled brick culvert east of Miltons Close where some residents celebrate its re-emergence with the ritual deposition of household debris and shopping trolleys.
The stream channel is approximately 2m in width and lies within an earth gully with steep banks that are 1m to 1.5m high. In may the stream itself averaged 3- 4cm in depth and consisted of a series of riffles with small shallow pools. By August the flow and other dimensions had halved. There is much small diameter rubble and small to mid size stones on the stream bed, most are held fast within the earth substrate. IN May at several locations garden waste within black bin liners had been thrown into the stream; this had been removed by August
The right bank supports a band of mature shrubs, mostly hawthorn, hazel and ash but with some field maple, blackthorn, dogwood, sycamore and wild privet. This bank is heavily shaded and supports a species poor ground flora dominated by ivy. The left bank has less shrub growth and correspondingly has a more herbaceous vegetation characterised by a 3-4m wide strip of tall herbs dominated by nettle.
Along the course of the stream banks, especially where there is sufficient light there are riparian plant species –typically pendulous sedge with some hemlock water-dropwort, figwort, wild angelica, wavy bitter-cress and meadowsweet.
For a distance of ten metres downstream of the Hareclive Road bridge the banks are hard engineered and the bank tops support a species poor tall herb flora.
P6. Hareclive Road to Fulford Road
There is a fifteen metre section of hard engineered bank immediately north of the Hareclive Road bridge but after this the channel returns to a more naturalistic form very similar to that seem in section B1 except that the stream channel is often deeper (with a 3m deep gully with steeply sloping and occasionally vertical banks). The stream bed is similar to that in B1 as is water depth and the nature of pools and riffles.
34 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Two foot bridges cross the stream in this section; the southern one has 4m of hard engineering downstream whilst the northern bridge (which appears to present difficulties of public access – crossing involves climbing over metal barriers) has no hard engineering.
The upstream half of this section is distinguished by shrubs being evenly spread across both banks thus creating an attractive alternation of shade and luxuriant tall herb vegetation. Plant species composition is very similar to that described for section B1 although some large crack willow and an occasional alder and Lombardy poplar add greater variety to the list of woody species and an increasing proportion of the tall herb community consists of rank grasses such as false oat-grass. Hemlock water-dropwort and great willowherb can be common on the edge of the stream in the more open areas.
Around the Briscoes Avenue road bridge there is a 3m hard engineered zone both upstream and downstream. North of the bridge there are some self-sown apples and a semi-mature English oak. The banks here are steep 2m high (mostly earth) cliffs and water depth averages 8cm. This section is particularly notable for outcrops of Lias limestone which are clearly visible within the overwhelmingly earth cliffs.
Spectacular dumps of domestic refuse and shopping trolleys, cruelly sacrificed to the dark-hearted river goddess, were to be found around the road bridges in May; these were an eyesore spoiling the aesthetics of an otherwise very attractive public open space and must be removed whenever they appear. By August these features had largely gone although scattered shopping trolleys were present in other downstream locations –possibly those from P6 that had been washed downstream.
In August a juvenile grey wagtail was recorded foraging along the stream here.
P7. Whitchurch Lane or Bust
This is the final stretch of Pigeonhouse Stream before it is culverted once more – this time for 300 metres under Whitchurch Lane and Hengrove Way. The Lias shelf continues here both within banks and the stream bed and creates a small waterfall –a very attractive feature. Steep (2-3m high) banks are typically found on the outer bends of meanders here whilst the inner bends of the meanders are lower –typically 1 -1.5m high. Except where the Lias outcrops the banks and stream bed are mostly of earth; there is some well-worn rubble and small stones within the bed and occasional areas of gravel.
With regards to the plant communities in many respects this section is very similar to section B2 but the belts of tall herb vegetation atop the banks are narrower here and there is proportionately more scrub and tree vegetation with
35 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
some large sections of bank downstream supporting many large semi-mature alders, ash and field maples with an occasional large crack willow. Of particular note are some shrubs which have rarely been encountered elsewhere along the stream: spindle and buckthorn –the latter is a relatively uncommon species in the wider countryside and any record of it is of some note. Dense thickets of blackthorn are also increasingly common to the north.
The tall herb / rank grass community supports an increasing quantity of cow parsley and hoary cress Lepidium draba; the northern edge of this section is notable for a very large area of unmown tall herb and rank grass. Within the scrub areas there are occasional records of both native and hybrid bluebell; apart from the native bluebell there is a very poor woodland species ground flora with no other species of note. A large expanse of an unidentified creeping plant – possibly a vine – was recorded on the left bank of this section some 30 metres above the culvert entrance.
The stream is culverted under Whitchurch Lane and Hengrove Way through a large concrete culvert with substantial metal grill.
A hoard of sacrificial objects offered up to Pigeonhouse –the South Bristol river goddess (Early I-Player Age: c 2000- 2010 AD) (Section P5)
36 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
P8. The Hengrove Lake District
Around the old Wills headquarters building there are two large pond features fringed by mature and semi-mature trees such as willows Salix spp. (both native and non-native), alder, ash, sycamore and dense scrub comprising such species as hawthorn, elder, hazel, dogwood and bramble.
The two ponds are effectively one: the Wills building (at the time of both surveys undergoing conversion into residential accommodation) being built over the waterbody giving the impression of two ponds. At the time of survey both ponds had been drained and comprised large extents of dried mud. The northernmost edge of the northern pond however has a small D-shaped terrace feature below the lip of the main pond edge. This lip is of concrete and there is a wide but very shallow flow of water down this spillway onto the concrete terrace. Around the fringes of the terrace there is a band of emergent and riparian vegetation with hemlock water-dropwort, pendulous sedge, flag iris, great willowherb and branched bur-reed.
Below the outflow of the terrace there were a large number of three-spined sticklebacks and one male beautiful demoiselle.
P9. Crox Bottom
Flowing through the Crox Bottom SNCI –an attractive public open space between the residential district of Headley Park and the A4174 Hartcliffe Way – Pigeonhouse Stream has two very distinct aspects.
In the south it is rather sluggish and heavily shaded. A series of masonry weirs have been built across the stream causing it to consist largely of pools usually 0.5- 1m deep but occasionally up to 1.5m deep or more in May. The stream is frequently 4m wide and flows over an earth bed with stones of varying sizes as well as patches of gravel. Given the slow flow here there is much deposition of silt on the bed. The banks (both comprising earth with some unstratified stone) are asymmetrical: the left bank is generally steep and 2m high whilst the right bank is generally 0.5m high and with a much gentler gradient. Within the stream there are small patches of curled pond weed and fennel pondweed Potamogeton pectinatus, both are tolerant of moderate levels of pollution.
On top of the left bank there is a thin band of mature scrub and semi-mature trees with a broad hard-surfaced footpath /cyclepath to the immediate west of this and only thin bands of tall herb /rank grassland community between them. The right bank however grades into semi-mature woodland where in spring there are large populations of ramsons with ivy generally the dominant ground flora species. Mature alder are very common along both banks with pendulous sedge and some hemlock water-dropwort common amongst these trees.
37 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
A footbridge crosses the stream in the south and just north of this there is a foul water outlet which was discharging an unpleasant-smelling milky-grey coloured fluid at the time of both May and August surveys. Near this point an adult kingfisher was recorded during the August survey.
The northern half of this section is in considerable contrast to the southern half. A large silt trap pond has largely infilled with silt (proving the design works). The eastern edge of this pond abuts dense scrub woodland which overhangs the very sluggish stream which meanders on the right (eastern) side of the pond. Large fish (possibly roach Rutilus rutilus or rudd Scardinius erythrophalamus) were noted just upstream of the silt trap pond.
The term pond is misleading here as effectively it is a wetland with a luxuriant emergent and tall herb vegetation dominated in the autumn by common reed Phragmites australis but with branched bur-reed Sparganium erectum more dominant in the spring. Bittersweet Solanum nigrum, greater pond sedge Carex riparia, flag iris Iris pseudacorus and great willowherb are all very common here. Pendulous sedge Carex pendula, hemlock water-dropwort Oenanthe crocata, great sweet-grass Glyceria maxima, water-starwort Callitriche sp., fool’s water- cress Apium nodiflorum, angelica Angelica sylvestris and water-cress Rorippa nasturtium-aquaticum are also frequent whilst common water-plantain Alisma plantago-aquatica is present but rare. In August trifid bur-marigold was common here and some fennel pondweed was recorded in the sections of deeper open water. The west bank of the pond has a very high level of light as recent felling works had removed an umber of mature and semi-mature trees here. This silted pond and its immediate environs would be expected to provide excellent conditions for many invertebrate species (large red damselfly Pyrrhosoma nymphula was noticeably abundant during the May survey) and is a rare habitat type within Bristol.
A wide foot /cycle bridge crosses the dam forming the upper (downstream) edge of the pond. There is a substantial spillway here with a 5m wide spread of what is effectively a thin smear of water running over the concrete. At the base of the shute is a 6m square concrete pool, the lip of which acts as a weir for the stream to flow over.
Downstream of the spillway the stream is fairly brisk and runs over a very rocky bed. The right bank is approximately 3-4m high, steep and covered with tall herbs and an occasional tree. The left bank is a very steep hillside supporting a mature broadleaved woodland with many large trees overhanging the stream and in May with a field layer dominated by ramsons. This section terminates near Hartcliffe Way where the stream is channelled into a very large metal grated and concrete sided culvert.
38 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Large red damselfly Pyrrhosoma nymphula was common during the survey around emergent vegetation in the Crox Bottom silt trap pond (P9)
P10. Hartcliffe Way / Pigeonhouse Stream – separate worlds / parallel lives
Emerging from the culvert which takes it under Hartcliffe Way Pigeonhouse Stream resumes a more typical form: in May the stream bed averaged 2m in width and had an approximately 8cm depth of water but in August these dimensions had fallen to 1m wide and between 4 and 6cm deep. The southern quarter of this section runs through very dense scrub and has steep sloping banks which run up to form part of the hillsides of adjacent fields. The stream bed is mostly silt and the banks are of earth.
The rest of this section has a more open aspect with numerous breaches in shrub and tree growth on both banks. Horses graze the fields on either side of the stream and there are many random horse trails through the scrub. Mature crack willow and alder are very distinctive trees here. On the right bank there is very dense scrub along the lower elevations of the field and this, combined with the mature trees lining both banks, reduces light levels so that ivy is the dominant ground flora species although ramsons is locally very common where light levels are better and there are also some patches of dog’s mercury here. Those areas with greatest exposure to light have dense stands of nettle, goosegrass and dock species.
39 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Many of the alder appeared unhealthy and may be dying from Phytophthora - a water-borne fungal disease to which alders are particularly susceptible. Some felling of alder and willow had taken place some months prior to the survey, this appeared to be unrelated to any works to make dead or dying trees safer as very healthy trees had been cut as well as diseased trees. The works appear to be more related to “tidying-up” the field edge, moreover the quality of the felling was very poor and resulted in straps of bark from the stumps being ripped off potentially causing serious injury to the trees.
40 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
7. Discussion
7.1 General Access was gained to approximately 85% of the sections of above-ground watercourse; thus a reasonably accurate assessment of the habitat quality and wildlife potential of this system has been obtained. Climatic conditions throughout the survey period were favourable and all surveys were undertaken in good weather thus helping ensure high surveyor effort.
The timings of the surveys were satisfactory as they were undertaken at times of year when sufficient plant species were readily identifiable and most faunal species, including breeding birds were active (spring) and dispersing juveniles recorded (August).
7.2 Variation between May and August surveys
Water levels were higher in May, as might be expected earlier in the year. Levels had fallen by between one third and one half by August.
The May surveys were notable for the rich woodland field layer assemblages in the headwater streams –particularly those of Pigeonhouse Stream. These colourful and interesting displays had mostly gone by August with only remnant vegetative material remaining of many of these species. Dog’s mercury, sanicle and wood vetch were notable exceptions to this with the latter two species still being in flower.
The August surveys were beneficial for identifying late developing species such as trifid bur-marigold and a number of alien species. Equally it was of value to contrast the silt trap communities in M10 and P9 between early and late summer. Reed had become dominant in P9 but this would not have been expected from the growth of this species here in May.
Both bird and invertebrate diversity appeared to have declined between the two surveys –as measured by records. With regard to the invertebrates this is most probably an artefact of the cool and overcast conditions during the August survey. With regard to the birds this will be due to the ending of the breeding season resulting in birds being less obvious. Of note in August however were sightings of Kingfisher (P9) and a juvenile grey wagtail (P6) – species which were not recorded in May.
41 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
8. Recommendations
It would be excellent to utilise current water engineering thinking and technology to restore sections of culverted stream where possible. Realistic opportunities to enhance the watercourses by re-wilding will be few however and are likely to arouse justifiable, though not always necessarily accurate, concerns regarding flood risk. However more small scale projects such as those described below have the potential to maintain and enhance the biodiversity of the Malago and Pigeonhouse Stream system and add to the public’s awareness and enjoyment of the streams and their wildlife.
Increase the size of the Dundry slopes SNCI The current boundaries of the East Dundry Slopes SNCI exclude many sections of woodland which support exceptional assemblages of ancient woodland indicator species. This exclusion places these areas at a greater risk of destruction through development or inappropriate management (e.g. scrub clearance, re-fencing field margins etc). It is proposed that these boundaries are amended to include the areas of woodland around the streams described in this report.
Litter clearance An opportunity exists in sections P5 and P6 (Hartcliffe) to undertake a major litter clearance operation. It may be necessary to make this a regular event (e.g. once a month) to ensure that a large build up of domestic debris is not encouraged. Engaging the local population in this project would be very beneficial.
The new Honda Stream-mower proved unexpectedly popular in South Bristol
42 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Investigation of foul water discharge It is recommended that Environment Agency (EA) staff investigate the discharge of foul discoloured water into the streams along sections M17, P3 and P9.
Remove invasive alien species –floating water pennywort This invasive species, currently only present in section M15, must be removed with immediate effect to prevent further infestation of the rest of the Malago / Pigeonhouse stream system. Removal must follow accepted Environmental Agency approved protocols.
Prevent veteran trees being used as fence posts A significant number of the veteran trees (mainly oaks and ash) in the headwater areas on Dundry slopes have multiple sections of wire fencing attached to them. Many have incorporated old sections of wire within their bark and in places this has caused injury and occasionally death to the tree. It is proposed that landowners and tenants are informed of the danger to these characterful trees and encouraged to erect purpose-made fence posts instead.
Tackle culture of arson on veteran trees. For many years veteran trees on the Dundry slopes and in Manor Woods have been subject to repeated acts of arson –mainly stacking combustible materials in hollows at the base of the trees and setting light to them. Several of these veteran trees have been killed or seriously weakened by this activity. The loss of such trees will affect both the nature conservation, historical and aesthetic value of the area. Educating local children on the great value of these trees and how easy they are to destroy may be of value.
43 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Arson attacks on large trees are frequent on the Dundry slopes headwaters; they will weaken the trees, encourage infection and lead to the death of the tree. They are also moronic.
Regular monitoring of semi-aquatic bird species It would be interesting to have data on the species of birds particularly associated with watercourses: moorhens, kingfishers, and possibly grey wagtails. It would be very valuable if local bird watchers, or dog walkers, can be encouraged to walk a particular length of stream whenever possible and make a note of any of these species with comments on what the birds were doing. This information, if supplied to a recognised person or small group to assist ease of data transmission, could lead to an understanding on breeding activity for example or critical times of year when parts of the brook will be of great value to particular species.
Information resources for local people. It is likely that many local people are not aware of the full interest and value of their neighbourhood streams. Whilst not pinpointing the locations of specific vulnerable wildlife it would be valuable to provide information resources (leaflets, walks, illustrated indoor talks, notice boards etc) that will inform people of what is in their streams.
44 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Ensure the watercourses are acknowledged at a policy level It is important that the Malago and Pigeonhouse Stream system is fully acknowledged as an important nature conservation and aesthetic resource at a policy level to ensure that this system receives funding for suitable and necessary projects and to ensure its continued protection within the Bristol Local Plan.
Maintain a diversity of habitats It is important that a wide diversity of habitats is maintained along the Malago and Pigeonhouse Stream system. This is particularly relevant with regard to areas dominated by tall herbs (such as nettles and docks) or brambles both of which are often seen as unsightly and of low conservation value. Although the aesthetic value of these plant communities is debatable their high nature conservation value is not and they are of far greater wildlife value than the amenity grassland or tree planting schemes which often replace them when these areas are viewed as wasteland and land managers seek to “enhance” their value. Tall herbs and brambles are especially important for invertebrates and a very high species diversity and biomass can be found here.
Thorough investigation of the need to de-silt sections of stream and silt trap ponds. The two main silt trap ponds are largely full of silt and support a rich and unexpected emergent flora with associated invertebrates. These are very important habitats and are rare within a Bristol context. However the silt traps will soon cease to serve their intended purpose and it may be necessary to remove the material from within them. To ensure minimum biodiversity loss it is recommended that all parties involved with these features agree a management plan to ensure that works only proceed when necessary from a public safety perspective and that they are timed to minimise disturbance to wildlife. It is also recommended that this protocol be applied to sections of the Malago downstream on the silt traps.
45 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
9. Conclusions
The streams comprising the Malago and Pigeonhouse Stream system are amongst the most natural and species rich watercourses in the urban Bristol area. They frequently have great aesthetic attraction and provide opportunities for many local people to experience attractive plants and landscapes as well as many opportunities to enjoy significant populations of butterflies, damselflies and birds.
Local people can be encouraged to monitor the wildlife of the stream system and to become actively involved in monitoring changes.
It is important that the high nature conservation and aesthetic value of this stream system is acknowledged at a policy level to ensure that resources are available to maintain and enhance features and to ensure that damaging works do not take place.
As one of the three watercourses linking Dundry Hill with the River Avon the Malago-Pigeonhouse Stream provides an essential green lung running through areas of dense housing, some with high levels of social deprivation. There are many opportunities provided by the streams for local people to enjoy nature, including scarce species, without having to leave the city
Tall herb vegetation alongside Pigeonhouse Stream, south of Whitchurch Lane (section P7)
46 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
10. APPENDICES
Species records
In the following accounts it is to be acknowledged that many plant and bird species occur throughout the entire Pigeonhouse Stream and Malago system. Only those species that are rare or otherwise notable or that were recorded in only a few locations are afforded a slightly more detailed account.
The following species are all incidental records. The omission of any species from these lists does not imply its absence from the survey area.
10.1 Plant species
Common name Scientific name Status in survey area
Field maple Acer campestre Frequent to common in upper reaches, increasingly less common downstream of Crox Bottom and Malago Valley SNCI Norway maple Acer platanoides Rare, mostly self-sown in lower reaches of Malago Sycamore Acer pseudoplatanus Occasional throughout Yarrow Achillea millefolium Rare in tall herb communities Moschatel Adoxa moschatelina Locally frequent in Pigeonhouse Stream headwaters & tributaries. Also scattered throughout Malago headwaters (M1,M6 & M7) Ground elder Aegopodium podigaria Occasional throughout Horse chestnut Aesculus hippocastaneum Rare but found scattered throughout Bugle Ajuga reptans Scattered throughout areas with more established open woodland e.g. M6 & M7, P2 (all sections) and P3 Common water-plantain Alisma plantago-aquatica Scarce, mainly in open areas of deep silt e.g. M10,M16 & M17, P8 & P9 Garlic mustard Alliaria petiolata Common throughout Ramsons Allium ursinum Frequently dominant, especially on upper reaches of Malago. Notably scarcer on upper reaches of the Pigeonhouse Stream. Occasional in downstream locations within established woodland Italian alder Alnus cordata Occasional within amenity tree
47 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
planting e.g. M5 Alder Alnus glutinosa Common in lower reaches of Pigeonhouse Stream (particularly P10); scarce on the Malago Wood anemone Anemone nemorosa Abundant in upper reaches of Pigeonhouse Stream (P1-4) and slightly less so in upper reaches of Malago (M4, 6 & 7) Wild angelica Angelica sylvestris Common throughout Cow parsley Anthriscus sylvestris Abundant throughout Fool’s water-cress Apium nodiflorum Occasional: on edges of streams where some silt and open conditions combine Thale cress Arabidopsis thaliana Occasional in disturbed ground in lower reaches of the Malago Burdock species Arctium spp. Occasional throughout especially in areas of tall herb False oat-grass Arrhenatherum elatius Very common /abundant in tall herb strips along the lower Malago (M15-16) and Pigeonhouse Stream (P5-7) Mugwort Artemesia vulgaris Occasional within open tall herb communities Cuckoo pint Arum maculatum Very common throughout areas of woodland and dense scrub Wall-rue Asplenium ruta-muraria Rare, only on masonry e.g. M17, M18 & M20 Maidenhair spleenwort Asplenium trichomanes Very rare, only on masonry of M20 Common winter-cress Barbarea vulgaris Scarce on stream edge and in tall herb vegetation away from Dundry slopes Daisy Bellis perennis Occasional in proximity to mown amenity grassland Trifid bur-marigold Bidens tripartita Locally common on left bank of M10 upstream of culvert grille; and amidst riparian tall herb community in silt interceptor pond of P9. An Uncommon plant species in the Bristol region Barren brome Bromopsis sterilis Occasional in disturbed ground in lower reaches of the Malago and in tall herb communities Buddleja Buddleia davidii Frequent within the downstream sections of the Malago especially M17-M20 Water-starwort Callitriche sp. Occasional in sections downstream of P8 and M9 Hedge bindweed Calystegia sepium Frequent and locally abundant within scrub and tall herb
48 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
communities in the downstream (urban) sections of both the Malago and Pigeonhouse Stream Large bindweed Calystegia silvatica Common throughout Adria bellflower Campanula potenschlagiana One large clump on masonry revetment of M17 Wavy bittercress Cardamine flexuosa Frequent throughout; especially on shady stream banks and in woodlands Hairy bitter-cress Cardamine hirsuta Occasional throughout Cuckoo-flower Cardamine pratensis Occasional throughout, mainly wooded headwater streams Grey sedge Carex divulsa Occasional throughout, especially in Dundry slopes headwaters Hairy sedge Carex hirta Occasional as part of tall herb communities in the downstream (urban) sections of both the Malago and Pigeonhouse Streams Pendulous sedge Carex pendula Common, occasionally very common, throughout Remote sedge Carex remota Occasional; particularly along the wooded banks of the Malago headwater streams Thin-spiked wood sedge Carex strigosa Rare; only recorded along sections P2f & P2g of Pigeonhouse Stream (lower Dundry slopes area) Wood sedge Carex sylvatica Very common along all the Dundry headwaters; frequent in M10 & M10a and P9. Black knapweed Centaurea nigra Rare in open scrub alongside some of the Dundry slopes headwaters Red valerian Centranthus ruber Rare; only in M18 & M20 Rustyback fern Ceterarch officinarum Rare, on masonry: only in M18 Opposite-leaved golden- Chrysosplenium oppositifolium Occasional on streamsides in saxifrage the wooded Dundry slopes headwaters Enchanter’s nightshade Circaea lutetiana Frequent within shady woodland and mature scrub throughout Creeping thistle Cirsium arvense Occasional as part of open tall herb communities Spear thistle Cirsium vulgare Rare, on edges of open tall herb communities Wild clematis Clematis vitalba Occasional throughout Pignut Conopodium majus Common in the headwater stream woodlands Field bindweed Convolvulus arvensis Rare: around edges of tall herb communities where there has been recent ground disturbance
49 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Canadian fleabane Conyza canadensis Only recorded in sections M18-20 where also with C. sumatrensis. Common in M19 Guernsey fleabane Conyza sumatrensis Rare, only on masonry; M18 & M20 Dogwood Cornus sanguinea Occasional throughout Non-native dogwood species Cornus sp. Rare; in association with amenity tree planting Hazel Corylus avellana Very common (locally abundant) throughout Hawthorn Crataegus monogyna Very common throughout Ivy-leaved toadflax Cymbalaria muralis Occasional on masonry throughout Cock’s-foot Dactylis glomerata Common throughout the more open areas Perennial wall-rocket Diplotaxis tenuifolia Scarce, only in association with highly urbanised sections of the lower Malago Teasel Dipsacus fullonum Occasional amongst the tall herb communities; common in the northern reach of P9 Broad buckler fern Dryopteris dilatata Occasional amongst the wooded headwaters on Dundry slopes Male fern Dryopteris filix-mas Frequent amongst the wooded headwaters on Dundry slopes also in the woodlands of M10, M10a and P9; scarce elsewhere White millet Echinochloa frumentacea An unusual alien grass, probably derived from bird- seed; present as at least two plants on left bank of M10 just above culvert grille, growing with trifid bur-marigold. Nuttall’s waterweed Elodea nuttallii Rare, only recorded in sluggish sections of P9. Possibly under-recorded Common couch Elytrigia repens Frequent within the tall herb communities; more obvious in late summer Great willowherb Epilobium hirsutum Common throughout Spear-leaved willowherb Epilobium montanum Occasional throughout Common horsetail Equisetum arvense Occasional throughout Great horsetail Equisetum telmateia Common (though localised) amidst the Dundry slopes headwaters; scarce elsewhere Spindle Euonymus europaeus Occasional amongst woodland and scrub throughout Hemp agrimony Eupatroium cannabinum Scattered throughout streamside locations, often in large clumps Wood spurge Euphorbia amygdaloides Rare: only recorded as a small population in P2g Japanese knotweed Fallopia japonica Rare; only on part of the
50 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
railways embankment at M18 Meadowsweet Filipendula ulmaria Occasional throughout, especially amongst tall herb communities Wild strawberry Fragaria vesca Rare; only recorded in P2g Ash Fraxinus excelsior Abundant throughout Goosegrass Galium aparine Abundant throughout, especially amongst tall herb communities Sweet woodruff Galium odoratum Abundant along much of the Pigeonhouse Stream headwater network, especially in established woodland. Herb robert Geranium robertianum Frequent throughout, especially in open woodland or scrub Herb benet Geum urbanum Frequent throughout, especially in open woodland or scrub Ground ivy Glechoma hederacea Frequent amongst woodland and scrub throughout Floating sweet-grass Glyceria fluitans Scarce, mostly in association with the silt traps of P9 & M10. Great sweet-grass Glyceria maxima Scarce, probably under- recorded; only identified along section M15 Plicate sweet-grass Glyceria notata Scarce, mostly in association with the silt traps of P9 and M10. Probably under-recorded Ivy Hedera helix Dominant or abundant in most of the woodland areas and particularly in areas of mature scrub Hogweed Heracleum sphondylium Frequent as part of the open tall herb communities Wall barley Hordeum murinum Rare; on edge of open tall herb communities Bluebell Hyacinthoides non-scripta Abundant along all the Dundry slopes headwaters, occasionally dominant in the ground flora. Scarce in the established woodlands of P9 and M10 / M10a; very rare elsewhere Hybrid bluebell Hyacinthoides x massartiana Occasional away from the Dundry slopes. A garden escape Floating pennywort Hydrocotyle ranunculoides Rare, only in a discrete area of M15 Tutsan Hypericum androsaemum Rare though consistent, most likely native rather than garden escape. In sections M7, M10, M10a, P2c-P2e. Hairy St John’s-wort Hypericum hirsutum Rare, only recorded in M9 and P2c
51 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Imperforate St John’s-wort Hypericum maculatum Very rare, only recorded as two plants in M7 Holly Ilex aquifolium Frequent but not common along the Dundry slopes headwaters, occasional in the established woodlands of M10 and P9; very rare elsewhere Himalayan balsam Impatiens glandulifera Occasional; only in any quantity in section M10 Flag iris Iris pseudacorus Scarce, mostly in association with the silt traps of M10 and P9, although also along section M15 Hard rush Juncus inflexus Occasional throughout, more so on Dundry slopes though never common. Prickly lettuce Lactuca seriola Rare, only along sections M16-20; locally common on former commercial site at M19 Yellow archangel Lamiastrum galebdolon Very common along the Pigeonhouse Stream headwaters; locally common along the Malago headwaters. Rare in the established woodlands of M10, M10a & P9 White dead-nettle Lamium album Occasional throughout although not recorded on the Dundry slopes headwaters Nipplewort Lapsana communis Occasional amongst the open tall herb communities throughout, and along walls in section M17, M18 and M20 Hoary cress Lepidium draba Rare, only recorded in lower reaches of section P7 where it is locally abundant Garden privet Ligustrum ovalifolium Rare; mostly recorded along the lower reaches of the Malago in Bedminster Wild privet Ligustrum vulgare Occasional throughout the Dundry slopes headwater woodlands and the established woodlands of M10 and P9 Purple toadflax Linaria purpurea Rare; occasional only in M19 Perennial rye-grass Lolium perenne Very common amongst the open tall herb communities and occasional elsewhere Honeysuckle Lonicera periclymenum Occasional throughout the Dundry slopes headwater woodlands and rare elsewhere Hairy wood-rush Luzula pilosa Rare, only recorded as a small clump in P2g Purple loosestrife Lythrum salicaria Scarce; only in number at the silt pond in M10 Water mint Mentha aquatica Occasional where a depth of
52 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
silt and open conditions combine Dog’s mercury Mercurialis perennis Very common / locally abundant throughout the Dundry slopes headwater woodlands and to a lesser degree in the woodlands of M10, M10a and P9; elsewhere only found in small quantity amongst dense established scrub. Wood millet Milium effusum Frequent but never common amongst the wooded headwaters of Pigeonhouse Stream and in section M6 on the upper Malago Three-veined sandwort Moerhingia trinerva Rare; only recorded on the eastern edge of woodland at M7 Garden forget-me-not Myosotis sylvatica (dom) Rare; a garden escape Garden daffodil Narcissus sp. Rare; a garden escape Hemlock water-dropwort Oenanthe crocata Very common throughout, locally abundant. Thrives in open conditions though will also tolerate shade Wood sorrel Oxalis acetosella Rare; only recorded as to clumps, one at M4 and the other on the lower reaches of P3 Yellow-juiced poppy Papaver dubium lecoqii Rare; only on bare ground meander in M10 Virginia creeper Parthenocissus quinquefolia Rare though locally abundant at M18 Amphibious bistort Persicaria amphibia Only recorded in silt pond in section M10 Redleg Persicaria dulcamara Local throughout Butterbur Petasites hybridus Two large patches on scrub free meanders in M10 Reed canary-grass Phalaris arundinacea Uncommon: in the silt trap communities in M10 and P9, and between M15 and M18 Common reed Phragmites australis Uncommon: in the silt trap communities in M10 and P9, also along M15 Hart’s-tongue fern Phyllitis scolopendrium Very common /locally abundant along the Dundry slopes headwaters and in the established woodlands of M10, M10a and P9. Scattered, though not uncommon, elsewhere where established dense scrub is present Intermediate polypody Polypodium interjectum Rare; occasional records from veteran trees along the Dundry slopes headwaters
53 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Soft shield fern Polystichum setiferum Occasional records from along the Dundry slopes headwaters; rare in the established woodlands of M10 and P9. Grey poplar Populus canescens Rare; in association with areas of planted trees Poplar Populus x canadensis Rare; in urban areas Curled pondweed Potamogeton crispus Uncommon but locally frequent downstream of P8 and M12 Fennel pondweed Potamogeton pectinatus Rare and scattered in P9 Silverweed Potentilla anserina Uncommon amongst open tall herb communities throughout Barren strawberry Potentilla sterilis Rare amongst the Dundry slopes woodland Primrose Primula vulgaris Frequent, though never common, component of the woodlands along the Dundry slopes woodlands; very rare in established woodlands of M10 and P9 Cherry Prunus avium (cult) Occasional along the Malago downstream of M11, invariably associated with gardens or tree planting schemes Blackthorn Prunus spinosa Common throughout English oak Quercus robur Frequent though never common along the wooded headwaters on the Dundry slopes; almost invariably as mature specimens Meadow buttercup Ranunculus acris Common Goldilocks buttercup Ranunculus auricomus Rare; only recorded within the woodland block of P2c; almost certainly under-recorded. Lesser celandine Ranunculus ficaria Very common throughout, especially in shaded areas Creeping buttercup Ranunculus repens Very common throughout Buckthorn Rhamnus cathartica Rare; only recorded once half way along the left bank of P7; probably under-recorded Gooseberry Ribes uva-crispa Rare; only recorded occasionally within the wooded headwaters on Dundry slopes Watercress Rorippa nasturtium-aquaticum Uncommon and only where there is a slack flow, sufficient silt and open conditions Rose species Rosa sp. Occasional throughout; some are most likely to be dog rose Rosa canina, others will probably be garden escapes Bramble Rubus fruticosus agg. Abundant throughout Water dock Rumex hydropiper Very rare; only recorded in
54 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
small number in M15 Broad-leaved dock Rumex obtusifolius Frequent throughout, especially amongst tall herb communities Wood dock Rumex sanguineus Very common throughout White willow Salix alba Rare, presumed mostly to be planted Goat willow Salix caprea Uncommon and mostly along the Dundry slopes headwaters Grey willow Salix cinerea Frequent throughout Crack willow Salix fragilis Occasional downstream of P7 and M9 Elder Sambucus nigra Common throughout Sanicle Sanicula europaea Uncommon and entirely restricted to the wooded areas of the Pigeonhouse Stream headwaters Common figwort Scrophularia nodosa Occasional along the Dundry slopes tributaries and in M10 and P9. Rare elsewhere. Common ragwort Senecio jacobaea Occasional, usually on the edges of tall herb communities. Rare elsewhere and mostly in association with walls and disturbed ground Red campion Silene dioica Occasional throughout, especially amongst wooded areas and scrub Stone parsley Sison amomum Rare; only on bare ground in M10 Bittersweet Solanum dulcamara Occasional, especially downstream of M10 and P9 Black nightshade Solanum nigrum Rare; on left bank of stream near silt pond in M10. Prickly sow-thistle Sonchus asper Occasional in areas of disturbed ground within the urban areas Smooth sow-thistle Sonchus oleraceus Occasional in areas of disturbed ground within the urban areas Branched bur-reed Sparganium erectum Common in the silt traps of M10 and P9; occasional in areas downstream of these sections –especially in M15 Hedge woundwort Stachys sylvatica Occasional in scrub and woodland throughout Greater stitchwort Stellaria holostea Scarce in the wooded headwaters of Pigeonhouse Stream Chickweed Stellaria media Occasional throughout in open and disturbed areas Russian comfrey Symphytum x uplandicum Occasional amid tall herb communities in the lower reaches of Pigeonhouse Stream and the Malago
55 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
Lilac Syringa vulgaris Occasional in the lower reaches of the Malago, especially adjacent to gardens Black bryony Tamus communis Scarce in the wooded headwaters of Pigeonhouse Stream and the Malago Dandelion Taraxacum officinale agg. Occasional, usually on the edges of tall herb communities. Rare elsewhere Fringecups Tellima grandiflora Rare; a small area along the lower reaches of M18 White clover Trifolium repens Occasional; in association with tall hedge communities amidst amenity grassland; rare elsewhere Greater reed-mace Typha latifolia Limited to the silt traps of M10 and P9 Wych elm Ulmus glabra Occasional amidst the woodland and scrub along the Dundry slopes headwaters; rare in M10 and P9 English elm Ulmus procera Rare; mostly as component of thin strips of scrub and large hedgerows along Malago headwaters (M3-M5) Nettle Urtica dioica Frequent as part of the open tall herb communities; occasional within the headwater woodlands and common in glades within dense scrub. Wild valerian Valeriana officinalis Rare; mainly in lower reaches of Pigeonhouse Stream headwaters e.g. P2e Lamb’s lettuce Valerianella carinata Rare- only in M20 Brooklime Veronica beccabunga Occasional throughout where there is a depth of silt and open conditions; most frequent around the silt traps of M10 and P9 Wood speedwell Veronica montana Very common /locally abundant throughout all the wooded headwaters on the Dundry slopes; downstream of the Dundry slopes only in P5 Ivy-leaved speedwell Veronnica hederifolia Occasional in association with disturbed ground throughout Guelder rose Viburnum opulus Scarce; mainly within the Dundry slopes headwater woodlands Tufted vetch Vicia cracca Occasional throughout within tall herb communities and on woodland and scrub edges Bush vetch Vicia sepium Occasional throughout within tall herb communities and on
56 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
woodland and scrub edges Wood vetch Vicia sylvatica Rare; only recorded along the lower reaches of the Pigeonhouse Stream and its tributaries on the Dundry slopes: sections P1, P2f & P2g Sweet violet Viola odorata Only recorded as scattered clumps in the Pigeonhouse stream headwaters P2c- P2e Early dog violet Viola reichenbachiana Locally frequent along the wooded Dundry slopes headwaters Rat’s-tail fescue Vulpia myuros Uncommon: only along M19 and M20
Yellow archangel Lamisatrum galeobdolon –a common and attractive species of the Dundry slopes tributaries
57 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
10.2 Fish species
Common name Scientific name Status in survey area
Bullhead Cottus gobio Occasional in lower reaches of the Malago Roach / Rudd Only in the sluggish channel of Pigeonhouse Stream within Crox Bottom. Possibly introduced by anglers. Waters too turbid to identify with accuracy Three-spined stickleback Gasterosteus aculeatus Frequent throughout all sections except the Dundry slopes headwaters where absent
Three-spined stickleback Gasterosteus aculeatus, the commonest species of fish within both the Malago and Pigeonhouse Stream
58 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
10.3 Bird species
Common name Scientific name Status in survey area Buzzard Buteo buteo Seen frequently over Dundry slopes; one bird being mobbed by crows over Crox Bottom (P9) Moorhen Gallinula chlorops Recorded in the silt traps in M10 and P9; possibly breeding Feral pigeon Columba livia (domest.) Frequent throughout urban areas Stock dove Columba oenas Male heard calling on upper slopes of Pigeonhouse Stream headwaters Woodpigeon Columba palumbus Frequent throughout though particularly on Dundry slopes Collared dove Streptopelia decaocto Frequent around housing Kingfisher Alcedo atthis One recorded in flight in August –P9 Great spotted woodpecker Dendrocopos major Recorded once in May - section M5 House martin Delichon urbica Occasional foraging above survey area Swallow Hirundo rustica Occasional over Dundry slopes Pied wagtail Motacilla alba Occasional throughout Grey wagtail Motacilla cinerea Recorded once – foraging in P6 during August survey Wren Troglodytes troglodytes Common throughout; pair observed taking food to nest in section M20 Dunnock Prunella modularis Frequent throughout Robin Erithacus rubecula Frequent throughout Blackbird Turdus merula Frequent throughout Song thrush Turdus philomelos Occasional throughout Chiffchaff Phylloscopus collybita Frequent on the Dundry slopes; elsewhere mostly around Manor Woods, Crox Bottom and Pigeonhouse Stream and Meadows SNCI Willow warbler Phylloscopus trochilus Rare; one male singing near Malago headwaters Whitethroat Sylvia communis Occasional around Malago and Pigeonhouse Stream headwaters –maximum of five singing males Lesser whitethroat Sylvia curruca Rare; one male recorded around Pigeonhouse Stream (P1 / P2f)/ Blackcap Sylvia atricapilla Common in areas of woodland and dense scrub, particularly on Dundry slopes Goldcrest Regulus regulus Occasional on Dundry slopes
59 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
area Long-tailed tit Aegithalos caudatus Small parties in more wooded sections, especially on Dundry slopes Blue tit Parus caeruleus Frequent throughout Great tit Parus major Frequent throughout Coal tit Periparus ater One bird recorded around section M5 Carrion crow Corvus corone Occasional throughout – mainly on amenity grassland Jackdaw Corvus monedula Frequent throughout; especially in association with housing and amenity grassland Jay Garrulus glandarius Frequent in wooded Dundry slopes headwaters Magpie Pica pica Frequent throughout Starling Sternus vulgaris Small groups on amenity grassland around; almost certainly common breeders around Hartcliffe and Withywood House sparrow Passer domesticus Locally frequent –especially around Withywood and Hartcliffe Goldfinch Carduelis carduelis Frequent throughout, especially in areas of tall herb vegetation Greenfinch Carduelis chloris Scarce but well –distributed Chaffinch Fringilla coelebs Occasional throughout Bullfinch Pyrrhula pyrrhula Occasional on the Dundry slopes area
10.4 Mammal species
Common name Scientific name Status in survey area
Roe deer Capreolus capreolus Occasional sightings and many field signs throughout the Dundry slopes woodlands and scrub Brown rat Rattus norvegicus Droppings very common throughout Grey squirrel Sciurus carolinensis Occasional in more wooded sections Fox Vulpes vulpes Droppings (scats) common throughout
60 Wildlife Survey of Pigeonhouse Stream and the Malago (2010)
10.5 Invertebrate species
Common name Scientific name Status in survey area
A micro-moth Adela reaumurella Approximately 30 males displaying and holding territory on the edge of a hedgerow (ST 581665)near the source of Pigeonhouse Stream Peacock Inachis io Occasional throughout Orange tip Anthocaris cardamines Occasional throughout in May Large white Pieris brassicae Common throughout Small tortoiseshell Aglais urticae Common throughout Speckled wood Pararge aegeria Common throughout Holly blue Celastrina argiolus Common throughout Common blue Polyommatus icarus Occasional in open grassy areas in August Gatekeeper Pyronia tythonius Frequent amongst open scrub in August Meadow brown Maniola jurtina Frequent throughout in August
Freshwater shrimp Gammarus pulex Common throughout Water louse Asellus aquaticus Occasional throughout Caddis fly larvae Limnephilidae Rare; only under stones in M10
Beautiful demoiselle Calopteryx virgo Common around sunny areas in P9, P10, M11-13 and M15 Blue-tailed damselfly Ischnura elegans Rare; only in the silt traps of M10 and P9 Large red damselfly Pyrrhosoma nymphula Common in the silt trap of P9; occasional in M12 and M18
The micro-moth Adela reaumurella (a male with typically long antennae)
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