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Nature conservation, water and urban areas in Britain
Urban Ecology, 9 (1985) 99-142 Elsevier Science Publishers B . V ., Amsterdam - Printed in The Netherlands
99
NATURE CONSERVATION, WATER AND URBAN AREAS IN BRITAIN JOHN G . KELCEY Consultant Ecologist, 4 Waterside, Peartree Bridge, Milton Keynes (Great Britain) (Accepted 14 March 1985)
ABSTRACT Kelcey, J .G ., 1985 . Nature conservation, water and urban areas in Britain . Urban Ecol ., 9 : 99-142 . The paper describes the ecology and nature conservation interest of the aquatic ecosystems of urban Britain . The paucity of published information is attributed to the historical lack of interest by the government's ecological and nature conservation agencies, research workers, and those concerned with the management of urban green space . Urban water bodies are classified according to their origins and use, as modified by age, size, water quality and level of public use . The plants and animals to be found in each category are described . Most of the information relates to London and to birds. However, London is atypical in many respects because of its size, large estuary, large parks, an active natural history society, and because it is the capital city . Apart from Milton Keynes (a new town) and some areas of the West Midlands, there is very little information about the ecosystems of other British towns and cities . The data indicate the importance of urban water bodies for the conservation of wildlife in Britain . The potential for improving the value for nature by ecological engineering is demonstrated . The diffused management responsibilities are described together with the need to impose a discipline on the maintenance authorities by the preparation of management plans in order to ensure continuity and consistency of treatment. A programme of research is advocated on the basis of the re-allocation of existing funds . The prime objective of such a programme is the acquisition of pragmatic information that will allow planning, design and maintenance operations to respond to inevitable development whilst maintaining a high-quality environment-
INTRODUCTION
Unfortunately, ecologists in Britain have shown very little interest in the urban environment, although together with agricultural ecology it provides the most stimulating, exciting and exacting ecological challenge in the world today . What interest there is in Britain can be divided into two categories : (1) Wildlife in towns has stimulated the curiosity and interest of naturalists and natural history societies for many decades . This interest has
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100 centred around curios and the collection of esoteric information related to the occurrence of unusual behaviour of less common species . For example, kestrels (Falco tinnunculus) nesting on office blocks, the occurrence of alien plants on rubbish tips . By far the most studies have been carried out in London by the London Natural History Society, whose area includes large tracts of countryside . It is therefore not typical and virtually nothing is published about other towns and cities . (2) The Government's main environmental research agency, the Natural Environmental Research Council (NERC), which includes the Institute of Terrestrial Ecology (ITE), has shown little interest in urban ecology and has funded or commissioned very little research on the subject . The Nature Conservancy Council (NCC), the Government's nature conservation agency, whilst professing great interest in urban nature conservation, has funded few studies of it when compared with the rural environment . However, a general survey of the wildlife of the West Midlands was commissioned by one of its regional offices (Teagle, 1978) . Both the ITE and the NCC are carrying out national vegetation surveys but neither include a consideration of urban vegetation, although the NCC survey does include a description of vegetation types that occur in urban areas, e .g. ruderal communities . Tansley (1965) in his classic work on British vegetation overlooked urban vegetation, as have recent and more detailed studies of moving water by Haslam (1978) and Haslam and Wolseley (1981) . Harrison and Grant (1976) are primarily concerned with the birds of the Thames, only referring to other organisms in so far as they affect birds . A survey of the rivers of the Southern Region of the Nature Conservancy Council (Hattey, 1977) excluded the rivers of Milton Keynes . This lack of interest is in marked contrast to that in Berlin (Sukopp and Murkstein, 1980 ; Jurging, 1980 ; Grosch, 1980) and Japan (Numata, 1983, 1984) . Why most ecologists, naturalists and conservationists abhor the urban environment with its complex diversity of species, habitats, structures, patterns and functions of space, buildings and people is a mystery . Especially when preference is given to the preservation and protection of the artificial, man-made moorland landscapes of Dartmoor, the Pennines and other similar areas with endless tracts of Calluna uulgaris and Nardus stricta .
As the rural environment becomes more and more intensively farmed and improvements (especially land drainage) continue, urban areas will become more important refuges for wildlife . For it is in urban areas where there is growing pressure for increased landscaping and habitat creation . Another example is Milton Keynes, a new British city situated between London and Birmingham . Prior to the start of development in 1969, the land was highly agriculturalised . Corn is as sterile as concrete and the wildlife was largely confined to road verges, canals, hedgerows, spoil heaps
101 and a few relict woodlands ; paradoxically most of these habitats are man-made . The extensive landscaping of the city provides opportunities for the creation of a wide range of habitats, e .g . 7 .0 km 2 of woodland and 1 .3 km= of grassland alongside the roads alone (Kelcey, 1975) ; 135 ha of water will also be created . If these opportunities are exploited in Milton Keynes and the other new towns, they will be much richer in wildlife than they were before development started, although some quantitative changes will obviously occur . This paper describes the scant information that is available about the aquatic ecosystems of urban Britain, with particular emphasis on their nature conservation interest . Most of the data are concerned with London, there is little to report from other places . It demonstrates how little is known and it is hoped that it will stimulate more thorough and analytical studies of urban areas outside the capital . But there is a more important reason for more detailed ecological studies . In Britain water is treated by most urban planners, designers and managers as a liability, a substance to be culverted, canalised and constrained . The River Thames and River Mersey are monuments to long dead municipal 'benefactors' ; streams disappear into insatiable concrete mouths, the canals of our major cities have been abandoned and made inaccessible whilst the park lakes cry for lack of imagination . Why should this be so? Ignorance? We cannot hope to manipulate and exploit natural resources until we have formed a picture of them and know how they function . USES OF WATER
The primary uses of water in towns are for transport, consumption, waste disposal and industrial processes (e.g. cooling) . The secondary, 'nonessential' uses include recreation, amenity and wildlife conservation . However, most water is put to multiple use, e .g. supply reservoirs are used for sailing and angling as well as being important wildfowl refuges . ECOLOGY OF DIFFERENT TYPES OF WATER BODIES
Table 1 shows a classification of water in urban areas . Each category is subject to three continuous variables : (1) Age ranges from a day to several hundreds of years . Many natural water bodies have been modified to varying degrees whilst field ponds (generally created by man) have been incorporated into landscape schemes when the land has been developed . The ecological impact of these changes is not known. (2) Size of both still and moving water varies continuously from 1 mz or less to several hundreds of hectares . At various arbitrary and undefined sizes the water body is given a name, e .g. pond, lake, river, stream, ditch,
102
TABLE 1 A classification of urban water STILL Natural Temporary pools Lakes Man-made Ponds ornamental amenity garden ex-agricultural mill Industrial flashes (subsidence lagoons) sewage lagoons slurry lagoons burrow pits Flooded/disused mineral workings colliery pits gravel pits clay pits sand pits Reservoirs supply compensation impoundment Recreational power boats sailing/rowing model boating angling paddling/swimming Other Royal Parks, London parks and other areas based in the grounds of large, well established houses/ buildings MOVING Natural streams rivers estuaries Man-made ditches dykes canals MARSHES fen (or alkaline) neutral hog (or acid) salt marsh
103 dyke. However, it may be that the surface area to depth ratio is of greater ecological significance than size, although it is a `parameter' which appears to have received little attention . (3) Water quality varies from clean to grossly polluted . In general, urban water bodies seem to be mesa to eutrophic although streams draining mineral workings may be acid, whilst some clay and gravel/sand pits are oligotrophic . STILL WATER
Natural still water bodies Temporary pools Following rain or snow, small pools of about 1 mz or less appear and last for a few hours to a few weeks . Those that form in spring are often used by undiscerning frogs (Rana temporaria) and toads (Bufo bufo) for spawning . The spawn or tadpoles die as the pond dries up . The common newt (Triturus vulgaris) is also reported from such ponds (Yalden, 1965) . Lakes It is not known how many (if any) lakes of natural origin there are in British towns and, if there are any, to what extent they have been modified . Man-made water bodies Ornamental ponds . Ornamental ponds are usually not more than 50 cm deep, lined with concrete or tiles, have vertical sides and a base often at normal land level . They are most often found in public open space as part of a formal landscape, occurring either as a feature (often with a fountain), e.g . Trafalgar Square, London (Fig . 1), or surrounding and protecting sculptures . The organisms present are restricted to plankton and small invertebrates. The concrete base of a formal pond in Milton Keynes developed a thick layer of the alga Haematococcus sp. within a few weeks of it being filled . A list of the phytoplankton found in this type of pond is given in Table. 2 . Garden ponds . Ponds in the gardens of average-sized houses and in school grounds are small, i .e. 6 m 2 (or less), and generally lined with polythene, fibre-glass or concrete . Beebee (1979) calculated that 70% of garden ponds in and around Brighton contained less than 1000 1 of water, although he believed 1500 1 to be a more realistic figure . These ponds are planted with a wide variety of native and exotic plants, which are generally bought from commercial nurseries or garden centres . Some of the species found are listed in Table 3 .
104
Fig . 1 . Ornamental pond, Trafalgar Square, London .
TABLE 2 Phytoplankton of a formal pond, Milton Keynes Cladophora sp . Stephonodiscus/Cyclotella sp . Anomoeoneis sp . Oedigonium sp . Chlamydomones sp . Nacicula sp . Oscillatoria limosa Spirogyra sp .
Eudorina elegans Microspora sp . Diatorna elongatum Synedra sp . Pinnularia viridis
Tabellaria flocculosa Anabaena sp .
Unless otherwise stated the tables have been compiled from a great many sources, including the author's observations . Garden ponds support a rich invertebrate fauna including several species of mollusca, corixids, crustaceans, coleoptera larva, neuroptera and odonata . The frog (R . ternporaria) is declining in many parts of Britain (Cook, 1972 ; Burton, 1976) but is thriving in garden ponds along with other amphibians including toads (B- bufo), smooth newts (T. oulgaris) and great crested newts (T. cristatus) . Beebee (1979) found that 15% of the gardens he surveyed contained ponds, breeding occurring in half of them . From this he estimated that his study area of 70 kmz contained 44 000 adult frogs, i .e . seven animals per ha, about the same density as rural England in the early 1950's .
105 TABLE 3 Wetland plant species
Acorns calamus Alusmaplantagoaquatica Alopercurus genieulatus Angelica sylvestris Apium nodiflorum Beruia erecta Bidens cernua B. tripartita Butomusumbellatus Callitriche stagnalis Calthapalustris Cardamine amara
(1)
(2)
(3)
+ +
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+
+
(4)
(6)
(6)
+ +
+
+ +
+
+
(7)
(8)
(9)
(10) (11)
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+
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+ +
+ +
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+
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+ + +
+ + + +
C. flexuosa
+
C. pmtensis
+
+ +
Carex acutiformis
C. otrubae C. paniculata
+
C. pseudo-cyperus C. riparla
+ +
Ceratophyllum demersum Cirsium palustre Eleocharispalustris Elodea canadensis Epliobium hirsuturn E. palustre Equisetum fluviatsse Eupatorlum cannabinum Filipendula ulmaria Galium palustre Geum rile Glycerin fluitans G . maxima G. plicata Gnaphalium ulignosum Hippurus vulgaris Hottonia palustris Hydrocharis morsus-ranae Impatiens glandulifera 1. capensis Iris pseudacorus
+
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J. compressus J. conglomeratus
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J. effusus
+
Lemna gibba L . minor L. trlsulca Lychnls flos-cuculi Lycopus europaeus Lysimachia nummularia L. vulgaris Lythrum salicaria Mentha aquatica
+
+
Juncus acutiflorus J. articulates
J. inflexus
+
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+
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+
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+
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Menyanthes trifoliata
+
Myosotia scorpleldes My osoton aqwile um Myriophyllum aiterniflorum M. spicatum M. verticillatum
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To be continued
106 TABLE 3 (continued) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) Nupharlute . Nymph.,. alba Nymphoides peltata Oenanthe crocata Petasites hybridus Phalaris arundinaceo Phragmites australis Polygonum amphibium P . hydropiper P. mite Potamogeton beehtokifi P. compresses P. crisp us P.lucens P+ natans P. pectlnatus P. perfoliatus P. pusillus P. trlchoides Potentitla paiustris Raouncuius aquatica agg . R . flammulo K . fluitans R . lingua R . repens R . scleratus Rorippaamphibia R . islandica R . nasturtium-aquaticum Rumex hydrolapathum R . palustris Sagitfaria sagiftifolia Scirpus lacustris Scrophularia aquatica Scutellaria galericulata Sparganium emenum .S . erection Stachys patustris Stellaria alone 'Priglochin palustre 'Ivphaangustifolium T. tatifolia Vateriano dioica V. officindlis Veronica anagadlis-aquatica V. beccabunga V_ catenata Zannichetlia palustris
+ +
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(1) garden ponds ; (2),ex-agricultural ponds ; (3) gravel pits ; (4) sand pits ; (5) compensation reservoirs ; (6) balancing lakes ; (7) grounds of former stately homes ; (8) Martins Pond, Nottingham ; (9) newly created ecological park ; (10) rivers/streams ; and (11) canals.
Neither age, volume, local geology nor the presence of aquatic vegetation are important in determining the suitability of a pond for breeding (Beebee, 1981) . Newts prefer ponds without fish whilst toads prefer the presence of fish . Beebee (1981) describes the ideal newt pond as having no fish, a surface area of < 200 in', 5-50% aquatic vegetation cover, an ionic score of < 400 ppm and a depth of 0 .5-1 .0 m . He recommends
107
Fig. 2 . Pond outside Bletchley Leisure Centre, Milton Keynes .
that ponds be improved for amphibians by keeping some free of fish and waterfowl, not cleaning them out between February and September and permitting the growth of dense vegetation (e.g. flower beds) around at least part of the perimeter . Teagle (1978) found frogs to be well established in gardens in the West Midlands although toads and smooth newts (T. uulgaris) were less frequent . He reports that 142 great crested newts (T. cristatus) were collected from a pond in the West Midlands . This species is also common in the ponds of Milton Keynes . Although garden ponds are often built to keep goldfish (Carassius auratus) and other exotic species, native species also occur in them including three-spined stickleback (Gasterosteus aculeatus), gudgeon (Gobio gobio), roach (Rutilus rutilus) and tench (Tinca tinca). The heron (Ardea cinerea) is a frequent visitor to garden ponds where it finds excellent eating for little effort. The larger amenity ponds in parks and other public open spaces support a similar flora and fauna to those of garden ponds (Fig . 2) . Ex-agricultural ponds. In many new towns, e .g. Runcorn, Warrington and Milton Keynes, field ponds have been or are being incorporated into landscape schemes (Fig . 3) . Several new town development corporations have undertaken pond surveys : Warrington (Moffatt, 1973), Central Lancashire (Hughes and Hibbert, 1973) and Irvine (Weyl, 1978) . Moffatt (1973) used the Trent Biotic Index to assess the wildlife conservation value of the ponds
108
Fig . 3 . Agricultural pond, Milton Keynes, Photograph taken just before the start of housing development.
in an area of Warrington (Fig . 4) . Only three fish and two bird species were recorded : perch (Perca fluviatilis), roach (R . rutilus) and three-spined stickleback (G. aculeatus), and moorhen (Gallinula chloropus) and mallard (Anas platyrhynchos), respectively . But how far is it safe to apply an index developed for rivers to ponds? The Trent Biotic Index was devised by the Trent River Board in the mid-1960's as a rapid technique for assessing the water quality of streams and rivers . It is based on the presence/absence of a number of `species groups' that are tolerant of or sensitive to pollution . The 10-point scale ranges from clean water (10) with > 16 Plecoptera nymphs distributed amongst > 1 species to very poor water (1-0) with < 1 tubificid worm/red chironomid or no animals, respectively (Woodiwiss, 1964) . The retention of this type of pond presents four problems : (a) they normally require general rehabilitation ; (b) will they hold water after the land drainage has been improved and the water table has dropped? (c) can an adequate water supply of the right quality be maintained after the drainage pattern has been disturbed? (d) what quantity of water is required to keep the pond full? Where such ponds have been retained, the flora (Table 3) and fauna are similar to that found in garden ponds but without the exotic species . Mill ponds . Associated with the derelict cotton mills of North-West England
are mill ponds. Little seems to be known about their natural history .
109
I ndices
60
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3 indicate
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capability to support fish
O W W G
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3 l 4 Trent
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Fig . 4 . Assessment of ponds, Bridgewater, Warrington, using the Trent Index .
Water bodies formed by industrial processes
Industrial operations have resulted in the creation of a number of different types of water bodies varying in character and depth, although most are shallow, i.e . about 2 .0 m . Subsidence lagoons . Westerport Lake (10 ha) in Stoke-on-Trent was formed
in the 1890's as a result of subsidence . In recent years it has been rehabilitated to become the core of a water park. The scheme included provision for boating, model boating and a nature study area with a range of habitats and natural plant communities (Land Use Consultants, 1972) . Flashes (the name given to water bodies resulting from land subsidence) in the Cheshire salt field contain a variety of salt-tolerant species (Lee, 1975) . Observations indicate that the presence of amphibia in these waters is low or non-existent . Many flashes have become nature reserves and/or sites of special scientific interest (SSSI), mainly because of the value for birds .
110 TABLE 4 Wetland bird species
Gaoia immer (great northern diver) Podiceps cristatus (great crested grebe) P. grisegena (red-necked grebe) P. auritus (Slavonian grebe) P. nigricollis (black-necked grebe) Tachybaptus ruficotlis (little grebe) Phalacrocorax carbo (cormorant) Ardeo cinerea (heron) Ixobrychus minutus (little bittern) Anusplatyrhynchos (mallard) A . crecca (teal) A . strepera (gadwall) Anuspenelope(wigeon) Aythya fuligula X nyroca (boer's Pochard) Aythya nyroca (ferruginousduck) A . acut . (pintail) A . manila (scaup) Spatula clypeeta (shoveler) Netta rufina (red-crested pochard) Aythya fuliguba (tufted duck) A . ferina (pochard) Bucephala clangula (goldeneye) Clangula hyemaiis (long-tailed duck)
(1) (2) (3) (4) (5) (6) (7)
(8) (9) (10) (11) (12)
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Merges sermtor (red-breasted merganser) Al . merganser (goosander) M . albellus (smew) Tadorna tadorna (shclduck) Anser albifrons (white-fronted goose) Brenta canadensis (Canada goose) + Cygnus olor (mute swan) Porzana porzana (spotted crake) ltallus aquaticus (water rail) + Gollinula chloropus (moorhen) + Fulica afro (coot) ttoematopus ostrulegus (oystercatcher) + Charadrius hiaticula (ringed plover) + + C. dubius (little-ringed plover) Pluviaiis squatarola (grey plover) + P. apricariu . (golden plover) + Gailinago gallinago (snipe) Lymnocryptes minimus + (jacksnipe) + Numenha arquata (curlew) + N. phaeopus (whimbrel) Limosa iimosa (black-tailed godwit) + + 7)-inga ochropus (teen sandpiper) T. hypoleucos (common sandpiper) + + T . totanus (redshank) + T. crythropus (spotted redshank) + T. nabularia (greenshank) + T. sohtaria (solitary sandpiper) Caiidris canutus (knot) + C. minute (little stint) C- temminchii (Teraminck's stint) C . melanctos (pectoral sandpiper)
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111 TABLE 4 (continued) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) C. alpine (dunlin) C. testacea (curlew sandpiper) Philomachus pugnax (.if) Phalaropes tricolor (Wilson's phalarope) Recurvitostra avosetta (avocet) Larus marinus (greater black-backed gull) L. fuscus (lesser black-backed gull) L. ergentatus (herring gull) L. canes (common gull) L. glaucoides (glaucous gull) L. hyperboreus (Icelandic gull) L. minutes (little gull) L. ridibundus (black-headed gull) Rissa tridactyla (kittiwake) Chlidonias niger (black tern) Sterna hirundo (common tern) S_ rnaerurn (Artic tern) S. albrfrons (little tern) S. sandvicensis (Sandwich tern) Chlidonias leucopterus (white-winged black tern) Plautus atle (little auk) Alcedo atthis (kingfisher) Riparia riparia (sand martin) Cinclus cinclus (dipper) Locustella naevia (grasshopper warbler) Acrocephalusscirpaceus (reed warbler) A. schoenobaenus (sedge warbler) Motacillu albs (pied wagtail) M. tines (grey wagtail) M . (lave (yellow wagtail) Emberiza schoenialus (reed bunting) Cygnuscygnus(whooperswan) C. columbianus (Bewick's swan) Pond ion haliaetus (osprey) Air galericulata (mandarin duck)
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(12)
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(1) sewage works ; (2) gravel pits ; (3) sand pits ; (4) clay pits ; (5) supply reservoirs ; (6) compensation reservoirs ; (7) recreational lakes ; (8) Royal Parks, London ; (9) grounds of former stately homes ; (10) newly created ecological park; (11) rivers ; and (12) canals .
An SSSI is a statutory designation that the NCC can apply to areas that it believes to be of scientific interest . The NCC is required to notify the landowner of the designation and of any damaging operations . The landowner is required to give the NCC at least 3 months notice of his (or her) intention to undertake any work that will damage the site . The NCC must also inform the local planning authority, who must in turn notify the NCC of any planning application it receives in respect of the site . Sewage works . The older sewage works attract a wide range of birds and bird-watchers. In the winter, birds are present in large numbers but the
112 TABLE 5 Wetland bird species breeding at sewage works Podiceps cristatus (great crested grebe) Tachybaptus ruficollis (little grebe) Anas platyrhynchos (mallard) A . crecca (teal) Spatula clypeata (shoveler) Aythya fuligula (tufted duck) Cygnus olor (mute swan) Rallus aquaticus (water rail) Gallinula chloropus (moorhen) Fulica atra (coot) Haematopus ostralegus (oystercatcher) Charadrius hiaticula (ringed plover) C, dubius (little-ringed plover) Gallinago galiinago (snipe) Numenius arquata (curlew) Tringa totanus (redsbank) Alcedo atthis (kingfisher) Locustella naeuia (grasshopper warbler) Acrophalus scripaceus (reed warbler) A . schoenobaenus (sedge warbler) Motacilla alba (pied wagtail) M. cinera (grey wagtail) M. (lava (yellow wagtail) Emberiza schoeniclus (reed bunting) From Fuller and Glue (1980) .
range of species is small. Spring and autumn migrants, especially waders and passerines, visit in quantity, whilst a large variety of species feed at sewage works during the breeding season . A detailed account of sewage works as a habitat for birds is given in Fuller and Glue (1980) . The bird species seen and those breeding at sewage works are given in Tables 4 and 5, respectively . Like ponds and lakes, sewage works are good breeding grounds for large numbers of diptera, which attract such insect-eating birds as swallow (Hirundo rustica) and swift (Apus apus) . Burton (1974) recorded 31 species of aquatic molluscs at Rye Meads Sewage Works, near London, where water shrew (Neomys fodiens) and water vole (Aruicola amphibius) were also recorded . Slurry lagoons . In Warrington, Cheshire, silt from the Manchester Ship Canal is pumped into a series of lagoons, which vary in their degree of wetness . The vegetation cover varies with wetness, from open wet silt to dense willow (Salix spp .) scrub . The lagoons provide a range of habitats for a wide variety of birds from gulls, ducks and waders to passerines and birds of prey .
113
Tailings from a variety of chemical processes are settled in extensive lagoons throughout Cheshire and Lancashire . The main value of these barren expanses is for birds. Large flocks of waders and seabirds occur, unusual and rare species can often be seen amongst them . Flooded/disused mineral workings The extraction of sand, gravel (Fig . 5) and clay has created a large number of pits throughout Britain . Sand pits . The Shewalton Sand Pit complex in Irvine, Scotland, is a nationally important site for wildlife (Weyl, 1978) . Twenty-nine of the 200 plants found there are wetland species, several being rare locally . More than 88 bird species have been seen at the pits ; the wetland species are listed in Table 4 . Some of them are unusual in or rare visitors to that part of Scotland . Weyl (1978) also reports the occurrence of 49 species of aquatic beetle as well as Odonata and amphibians . The older pits have developed a marginal vegetation that includes Typha latifolia, T. angustifolia, Scirpus
Fig . 5 . Wildlife Conservation Area, Stony Stratford, Milton Keynes . A nature reserve created as a result of gravel extraction for road construction .
1 14
lacustris, Phragmites australis and Glyceria maxima . A list of plants of sand pits is given in Table 3 . Gravel pits . A general account of the birds of gravel pits is given in Catchpole and Tydeman (1975) . They divided the breeding bird communities into two groups : (1) Aquatic, with coot (Fulica atra), mallard (Areas platyrhynchos) and great crested grebe (Podiceps cristatus) as the dominant species . Of secondary importance are moorhen (Gallinula chloropus), tufted duck (Aythya fuligula) and common tern (Sterna hirundo) . (2) Terrestrial, dominated by reed bunting (Emberiza schoeniclus), reed warbler (Acrocephalus scirpaceus) and sedge warbler (A . schoenobaenus) . The breeding community of a gravel pit is shown in Fig . 6 . Gravel pits have been responsible for the spread of two birds across Britain, the great crested grebe (P. cristatus) and the little ringed plover (Charadrius dubius) . Apart from their value for breeding, gravel pits proGreat crested grebe Meadow pipit yellow wagtail Bullfinch Whitethroat
Skylark
Woodpigeon Chaffinch Redpol l Turtle dove Robin Cuckoo Little ringed plover
Pied wagtail Common tern
Fig . 6 . The breeding bird community of Stanstead Abbots gravel pit (from Catchpole and Tydeman, 1975) .
115
vide important roosts and over-wintering facilities for large numbers of birds . The species seen on urban gravel pits are listed in Table 4 . The vegetation of gravel pits is listed in Table 3 . The ponds of Richmond Park, London (some of which are gravel pits), contain ten species of Odonata : Aeshna cyanea, A . grandis, Libellula quadrimaculata, L . depressa, Sympetrum danae, S . striolatum, Lestes sponsa, Ischnura elegans, Enallagma cyathigerum and Coenagrion puella (Bush, 1972) . Clay pits . Clay pits are of considerable ecological interest . The four small flooded clay pits in Milton Keynes are 3-4 ha and 12-22 m deep (Fig. 7) . Light penetration can be as much as 10 m . The phyto- and zooplankton
is poor, as is the bird population . The fish are reported to be few but large, though because of sampling difficulties fish population studies were not carried out to confirm the reports . Although the pits are physically similar (inverted cones or pyramids), they have different biological characteristics . The phytoplankton of two pits is dominated by Chlamydomonas sp ., whilst the zooplankton is dominated by Diaptomus sp ., with Cyclops strenuus and Daphnia hyalina being
Fig . 7 . Flooded, disused clay pit, Bletchley, Milton Keynes .
116
well represented . The benthic fauna is poor, no one species being present in any great numbers (Baldwin, 1979) . The phytoplankton of the two other pits is dominated by the dinoflagellates Ceratium and Peridinium. Hexartha dominates the zooplankton . Both these pits have rich benthic fauna in which Potamopygrus jenkinsi Asellus, Oligochaetes and Chironomus sp . are well represented (Barnes and Logan, 1977) . All the pits contain extensive Chara meadows . The floating-leafed and emergent vegetation is poorly represented in all but one of the pits where it was planted . Saltwell's clay pit in the West Midlands is a complex of water, woodland, scrub, heath, marsh and carr . It is of such wildlife value that is has been scheduled as an SSSI . The plants of clay pits are listed in Table 3 . Reservoirs There are three types of reservoirs in or on the fringe of urban areas . Supply reservoirs . Supply reservoirs are usually large, open, steep-sided and subjected to large fluctuations in water level . As a result the marginal and floating-leafed vegetation is generally poor . These reservoirs, like other large bodies of water, are important as roosting, feeding and resting places for birds, including migrants . A list of species seen on supply reservoirs TABLE 6 Fish species
Bream (Abrarnis brama) Bullhead (Coitus gobio) Carp, Common (Cyprinus carp to) Carp, Crucian (Carassius carassius) Dace (Leuciscus leuciscus) Eel (Anguilia anguitta) Golden orfe (Leuciscus idus) Goldfish (Carassius auratus) Gudgeon (Gobio gohio) Minnow (Phoxinusphoxinus) Perch (Perca luviatilis) Pike (Esox lucius) Roach (Ruttles rutilus) Rudd (Scardinius erythrophthalmus) Ruff (Gymnocephalus cornea) Stickleback, Three-spined (Gasterosteus acuteatus) Stone loath (Nemacheilus barbatura) Tench (Tinca lineal
(1)
(2)
+
+ + + + +
(3)
+ +
+ +
+ + + +
+ + +
+ + +
+ +
+
+
(1) London Supply Reservoirs ; (2) Royal Park lakes, London ; and (3) urban rivers in the West Midlands .
1 17
is given in Table 4 . Burton (1974) reported that 265700 gulls roosted on the London reservoirs in 1968 and that in 1969, 49 of the 64 smew (Mergus albellus) recorded in Britain were seen on the London Reservoirs . The London supply reservoirs are believed to contain all the common British stillwater fish, including the species listed in Table 6 (G .S. Armstrong, personal communication, 1984) . Species of moving water will have entered the reservoirs when water is pumped from the river for storage, although it is unlikely that these will have established breeding populations . Compensation reservoirs . Compensation reservoirs were built in the 19th century to keep the canal system supplied with water . The 51-ha Brent Reservoir in London was built between 1833 and 1837 . It now supports a variety of grebes, waders, gulls, terns and wildfowl similar to those found on the London supply reservoirs (Batten, 1977) . Because of its wildlife value the reservoir has been scheduled as an SSSI . More than 80 bird species have been seen on Edgbaston Reservoir, Birmingham, although the number of breeding species is much smaller (Teagle, 1978) . Some of the plants and birds associated with compensation reservoirs are listed in Tables 3 and 4, respectively . Quite often the inflow end of these reservoirs develops into carr woodland . reservoirs . Impoundment reservoirs (or balancing lakes) control urban run-off. They are shallow, between 1 .7 and 2 .0 m deep but subject to sudden changes in level, although the magnitude of the change is much less than that of supply reservoirs . The physical structure of balancing lakes varies from town to town and even within towns . Some are partly lined, some are not ; some are on-stream, whilst some are off-stream (Fig . 8) . They may support large bird populations, although on some reservoirs the bird population is inexplicably low. Because impoundment reservoirs have smaller fluctuations in water level and are shallow, they have a more abundant aquatic vegetation . It is therefore probable that the invertebrate fauna is also richer . A list of plant species is given in Table 3 . An ecological monitoring programme of the Milton Keynes balancing lakes was initiated by the author in 1975- It has resulted in the acquisition of a substantial and unique body of information about the water chemistry, physicochemical features, phytoplankton, zooplankton, pelagic and benthic invertebrates and the aquatic vegetation . The ecological and recreational aspects of these lakes are discussed in more detail in Hengeveld and De Vocht (1982) . Impoundment
Recreational lakes Most urban areas contain a recreational lake or lakes . The size varies from paddling pools of about 20 m 2 to boating pools of 1-2 ha (Fig . 9) .
118
Fig . 8 . Willen Lake, Milton Keynes . A balancing lake that is also used for a variety of recreational activities .
Fig . 9 . Boating Lake, Newquay, Cornwall .
1 19 All are shallow, i .e. 0 .5 m or less and usually have vertical walls . They have very little aquatic vegetation . Paddling and swimming pools are often heavily chlorinated to eliminate coliform bacteria and therefore contain no macroscopic organisms . Boating pools are relatively `sterile' although they may support a microscopic flora and fauna similar to that reported for ornamental ponds . The larger boating lakes are of surprising interest . In the summer of 1981 a boating lake in Helston, Cornwall, contained a considerable eel (Anguilla anguilla) population although few other fish were seen . Many lakes in this category have islands on which duck and other species breed . However, whilst these islands afford protection some are unsuitable for breeding and the ground is often bare as a result of heavy shading by evergreens . The sides are vertical, making it difficult for the birds to get on and off. To overcome this, some public authorities have provided duck ladders on water bodies within their jurisdiction . Teagle (1978) reports that mallard (A . platyrhynchos) have little breeding success on the boating lakes of the Midlands compared with London, where they are more adventurous and breed well away from water . A variety of bird can be seen on recreational lakes (see Table 4) ; a number of exotic species also occur but these are not listed .
Royal
Parks, London. There are six Royal Parks in London varying in size and character but all have been created and modified by various sovereigns over the last 500 years . They all contain a lake or pond, many of which are of wildlife value . For example, Regent's Park contains a heronry whilst the Serpentine in Hyde Park has a rich flora and fauna . Lee (1977) reports that the lake has a healthy fish population dominated by roach (R. rutilus) and perch (P. fluuiatilis) . When St . James's Park lake was drained in 1961, 15 000-20 000 roach (R, rutilus) and a few perch (P. fluuiatilis) were recovered . The fish species found in the Royal Park lakes are given in Table 6 . The bird species associated with the lakes are listed in Tables 4 and 7 . An account of the ornamental waterfowl is given in Simms (1974) . Blooms of Rhizoclonium hieroglyphicum and Oscillatoria limnetica have been recorded in St . James' Park lake (Pentelow, 1965) . The invertebrate fauna of this lake includes Daphnia sp ., Sympetrum striolatum, Lymnaea peregra and Asellus aquatieus . Of the amphibians, frog (R . ternporaria) and toad (B . bufo) are known to spawn in many of the Royal Parks.
Other lakes . The grounds of many stately homes and large houses have become incorporated into urban development as parks, hotels or commercial centres . In addition many public buildings are surrounded by extensive grounds, e .g. hospitals . Ninety bird species have been recorded in the grounds of St . Margaret's Hospital, Walsall, including a variety of water birds .
1 20 TABLE 7 Bird species associated with the Royal Parks, London (1)
(2)
(3)
(4)
(5)
(6)
Gauia immer (great northern diver) + Podiceps cristatus (great crested grebe) + + P. griseigena (red-necked grebe) + Tachypabtus ruficollis (little grebe) + + Phalacrocorax corbo (cormorant) + + Ardea cineru (heron) Ixobrychus minulus (little bittern) + + + + Anus platyrhynchos ( mallard) + A. crecca (teal) A . penelope (wigeon) + + Spatula ciypeata (shoveler) + Net to rufina (red-crested pochard) Aythya fuligula (tufted duck) + + + + + + + + + + A . ferina (pochard) Bucephala clungula (goldeneye) + Clangula hyernalis ( long-tailed duck) + .Merges merganser (goosander) + M. albelius (smew) + Todornatadorna(shelduck) Anser albifrons (white-fronted goose) + + + Branta canadensis ( Canada goose) + + Cygnus olor (mute swan) + Pandion haliaetus (osprey) + + Rallus aquaticus (water rail) + Gallinula chloropus (moorhen) + + + + + Fulica afro (coot) + Ilaernatopus ostralegus (oystercatcher) Charadrius dubius (little-ringed plover) + + + Gallinagogollinago(snipe) + Numenius phaeopus ( whimbrel) sandpiper) + + Triage hypoleucos (common T. nebularia (greenshank) + + Calidris alpina (dunlin) Recurvitostra avosettu (avocet) + Larus marinus (great black-backed gull) + + + L . fuscus (lesser black-backed gull) + L . argenlatus (herring gull) + + L. canes (common gull) L . glaucoides (glaucous gull) + h- hyperboreus ( Icelandic gull) L . ridibundus ( black-headed gull) + + Chlidonias niger (black tern) + Plautus alle (little auk) + Motacilla alba (pied wagtail) M. cinera (grey wagtail) + Emberiza schoeniclus ( reed bunting) Acrocephalus scirpaceus (reed warbler) Aix galericulata (mandarin duck) (1) St . James's Park/Green Park ; (2) Hyde Park/Kensington Gardens ; (3) Regent's Park/ Primrose Hill ; (4) Greenwich Park ; (5) Richmond Park ; (6) Hampton Court/Bushy Park .
121
Edgbaston Park, Birmingham (an SSSI), supports 47 bird species that are associated with water ; an account is given in Speak et al . (1975) . The park also contains an interesting flora ; the emergent vegetation of the pool merges into alder carr and then into the swamp garden of the university botanic gardens . Martins Pond, an old 2-ha fish pond within 6 km of the centre of Nottingham, contains 42 wetland plant species . The site is now a local nature reserve . The plants and birds associated with this general type of habitat are listed in Tables 3 and 4, respectively . Small nature reserves (about 1 ha) are being created, rather like wildlife zoos, in several major cities . One such reserve, the William Curtis Ecological Park in London, contains a pond in which there are 46 species of aquatic plants (see Table 3) and twelve bird species associated with water (see Table 4) ; Douglas (1981) also reports that frog (R . temporaria) and toad (B. bufo) breed on the site . MOVING WATER
Many towns and cities are built on the banks of rivers, whilst small tributaries and streams have become completely encroached by urban development . Many water courses have been modified by straightening, reinforcement or even culverting (Figs . 10 and 11) . Water courses running through public open space, playing fields, golf courses etc . have been treated in a variety of ways from over-zealous maintenance to total neglect . But in general, most rivers and streams have been treated with contempt by development . The Thames in London and the canals of London, Liverpool, Birmingham and Manchester are classic examples . Most water courses in urban areas are used for the disposal of Man's effluent, whether it be urban run-off, treated sewage or from industrial processes . Although improvements have been made over the last 2 decades, whether it is enough and in time remains to be seen. The cleaning-up of the River Thames is chronicled by Harrison and Grant (1976) ; it is doubtful whether a similar account could be written for most other urban water courses . The better treatment and landscaping of urban streams is strongly advocated by Keller and Hoffman (1977) and Kelcey (1978a) . The other water courses in this category and a common feature in the towns of the Midlands and North-West England are the canals . Most were dug out of the landscape in the 19th century, although some are improved natural watercourses . Unmodified streams . Streams (arbitrarily defined by the author as movingwater courses < 2 .0 m wide) have a waterside vegetation similar to that of canals (Table 3). Impatiens glandulifera, an introduced species, has spread rapidly along stream and river banks and is now abundant along many urban watercourses .
122
Fig . 10 . An `improved' watercourse, Milton Keynes .
Teagle (1978) records frog (R . temporaria), dragonfly (Aeshna grandis), Gammarus sp ., Poecilobothrus nobilitatus, Ancylus fluviatilis, crayfish (Astacus pallipes), mayfly and caddisfly larvae in the streams of Birmingham . Unmodified rivers . In Britain, rivers (defined by the author as moving water > 2 .0 m wide) are the responsibility of a number of water authorities that cover the country . Streams and dykes on the other hand are
1 23
Fig . 11 . An improved watercourse, Stevenage .
Fig . 12 . Duck ladders in a public park, Hemel Hempstead .
the responsibility of the riparian owner or in some cases of an Internal Drainage Board. Water authorities are responsible for the surveillance of water quality ; they do so using chemical and biological parameters . A number of biological indices have been devised, which use the presence
124
or absence of certain invertebrate species . The Trent, Index was used by Weyl (1978) to classify and monitor the changes in water quality of the rivers in hvine, Scotland, from 1967 to 1977 . Weyl (1978) records 127 invertebrate species in the Irvine rivers, which also contain salmon (Salmo salar) and brown trout (Salmo trutta fario) . The fish species recorded in the rivers of the West Midlands are given in Table 6 ; however, they are not a conspicuous part of the fauna . A surprising variety of birds is frequently seen on urban rivers (see Table 4) . The waterfalls and artificial nature of some of the streams simulate the fast flowing water of the uplands . The duck population of rivers in some urban parks has been encouraged and sometimes augmented with exotic species . For example, there is a collection of exotic waterfowl on Dawlish Water, Devon, whilst duck ladders have been provided in Hemel Hempstead to enable ducks to scale the steep banks (Fig . 12) . Andrews (1977) gives an account of the quantitative and qualitative. changes that occurred in the fauna of the River Thames during the 1976 TABLES Upstream penetration of the River Thames (near London Bridge) invertebrates following a period of drought 25 June 1975
2 August 1976
Crustacea Acanthocyclaps americanus Cyclops agilis speratus Cyclops vicinus Aselies aquaticus Crangonyx pseudogracilis Gam mares pulex
Eurytemora affinis Crangon crangon Gam mares salinus Neomysis integer Palaemon longirostris Sphaeroma rugicauda
Ephemeroptera Caenis moesta Hirudinea Erpobdella octoculata Glossiphonia heleroclita Mollusca Dreissena polymorpha Lymnaea peregra Physa fo nl inatis Potarnopyrgus jenkinsi Tuhificidae Limnodrilus ho ffmeisteri Psammoryctides barbatus Potamothrix hammoniensis Tubifex tubifex From Andrews (1977) .
Dreissena polymorpha Polamopyrgus jenkinsi
Clitellio arenaius
m
and estuarine
1 25
drought, especially the upstream penetration by marine and estuarine species . The changes in the invertebrate fauna are given in Table 8 . 216 species of macroinvertebrate have been found in the Thames tide-way and its main tributaries (Aston and Andrews, 1978) . The return of wildfowl to the River Thames and a systematic account of the status of the bird species associated with the river between 1900 and 1976 is given in Harrison and Grant (1976) . A detailed account of the fish of the tidal Thames (150 km) is given in Wheeler (1979) . Urban water courses often receive warm water from industrial plants and power stations, which enable unusual species to survive, e .g. Physa acuti, which is found in the River Cole, West Midlands (Teagle, 1978) . Biological surveys of the Rivers Ouse and Ouzel in and around Milton Keynes were commissioned annually from 1972 to 1974 by the Milton Keynes Development Corporation (MKDC, 1975) and from 1975 onwards by the Anglian Water Authority (MKDC, 1976) . The fluctuation in the number of animal species recorded in the River Ouzel is shown in Table 9. The animal species found in a section of the River Ouzel in 1972 and 1977 are given in Table 10 . The plant species of urban rivers are listed in Table 3 . TABLE 9 Changes in the number of animal species found in the River Ouzel in, above and below Milton Keynes
1972 1973 1974 1975 1976 1977
Upstream of Milton Keynes
Simpson Bridge, Milton Keynes
Downstream of Milton Keynes
29 29 29 30 28
14 2 9 14 12
27 15 21 23 20
From MKDC (1975, 1977) .
Estuaries . Many urban developments are associated with estuaries, which are important for birds, e .g. Irvine and the Firth of Forth in Scotland, the Mersey, Ribble and Thames in England . The birds of the Thames estuary are described by Harrison and Grant (1976) . It is thought that the reduction in the duck population of the Firth of Forth has been caused by the improvement of sewage effluent . It will be paradoxical if too much cleaning up of the environment is detrimental to wildlife conservation interests . The Surrey Docks, London, have been studied by Grant (1970) and Alderton (1977), who have demonstrated
1 26 TABLE 10 Animal species present in the River Ouzel, Simpson Bridge, Milton Keynes in 1972 and 1977 1972
1977
Annelids Erpobdella octoculata Glossiohonia complanata C. heteroclita Theromyzon tessulatum
Molluscs Lymnaea peregra L . auricularia Hydrobia jenkinsi Ancylus lacustris
Crustacea Asellus aquatic us Gammarus pulex Insects Agrionsplendens
Ishnura elegans Chironomid larvae
Erpobdella octoculata E. testacea
Tuhificids
Lymnaea peregra Physa fontinalis Hydrobia jenhinsi
Asellus equaticus
Coenagrion sp . Baetis VernuS
Chironomid larvae Fish Gasterosteus aeuleatus Cobitus taenia
From MKDC (1975, 1977) .
the value of the area for birds (see Table 11) . The Bogside Flats in Irvine has been designated an SSSI mainly because of the large number of waders and wildfowl it supports, including 1000-3000 over-wintering golden plover (Pluuialis apricarius) . Man-made watercourses
Ditches . Very little is known about the ecology of draining ditches . They
are small and often dry up in the summer months, carrying water only in times of rain . The banks are either well maintained or neglected . These water courses tend to attract large quantities of rubbish . Canals . Eight ecological zones can be recognised across a canal : three ter-
restrial (boundary hedge, tall and short grass) and five aquatic (open water, free-floating, submerged, floating-leafed and emergent) . There are also a number of micro-habitats including walls, bridges and lock gates . The flora and fauna are similar to that of slow-moving rivers. Baldock (1976) describes the Grand Union Canal, Milton Keynes, as supporting
127 TABLE 11 Water birds seen at Surrey Commercial Docks, London
Arias platyrhynchos ( mallard) A. crecca (teal) A . penelope ( wigeon) A . americana ( American wigeon) A . acuta (pintail) Spatula clypeata (shoveler) Aix galericulata (mandarin duck) Aythya marlin (scaup) A. fuligula (tufted duck) A . ferina (pochard) A. nyroca (ferruginous duck) Bucephala clangula (goldeneye) Mergus serrator (red-breasted Merganser) AT. merganser ( goosander) M. albellus ( mew) Tadorna tadorna (shelduck) Anser anser (greylag goose) Cygnus olor (mute swan) Gallinula chioropus (moorhen) Fulica atra (coot) Charadrius hiaticula (ringed plover) C . dubius (little ringed plover) Pluvialis squatarola (grey plover)
Gallinago gallinago (snipe) Lymnocryptes minimus (jacksnipe) Numenius arquata (curlew) Tringa ochropus (green sandpiper) T. hypoleucos ( common sandpiper) T. totanus (redshank) Calidris alpina (dunlin) Philomachus pugnax (ruff) Phalaropus fulicarius (grey phalarope) Sterna hirundo/S . maerura (common/Artie tern) Larus marinas (great black-backed gull) L, fuse us (lesser black-backed gull) L . argentatus (herring gull) L . canus (common gull) L . ridibundus ( black-headed gull) Rpparia riparia (sand martin) Locustella naevia ( grasshopper warbler) Acrocephalusechoenobaenus (sedge warbler) Motacilla alba (pied wagtail M. cinerea ( grey wagtail) M. flaw (yellow wagtail) Ember" schoeniclus (reed bunting)
a fauna that is typical of a hard, moderately eutrophic, slow-moving water with abundant weed and a muddy substrate . Zebra mussel (Dreissena polymorpha), which was introduced in the
19th century, has used the canal system to spread throughout the country . Elodea canadensis has done the same thing, using the same route . A survey of the Union Canal, Lothians, Scotland, found that the 30-km canal contained 220 plants of which 22 are aquatic, five being of limited distribution in the Lothians (Sheldon, 1976) . It includes Naumburgia thyrisfolia (which is rare in Britain as a whole) and Lemna gibba (which is rare in Scotland) . Seventy-eight invertebrate species were found including Erpobdella testacea, which was recorded in Scotland for the first time . Only three fish and three amphibian species were found . A programme to monitor the ecological effects of the urbanisation of 20 km of the Grand Union Canal, Milton Keynes, was started by the author in 1973 ; some of the results are summarised in Kelcey (1982) . The invertebrate fauna of a section of the canal is listed in Table 12 ; Table 13 lists the number of major plant and animal groups that have been found along the whole canal corridor. Seven of the 14 dragonfly species (Odonata) recorded in Milton Keynes breed in the canal : Aeshna grandis, A . mixta,
1 28 TABLE 12 Invertebrate fauna of a 100 m length of the Grand Union Canal in Milton Keynes Towpath side Platyheminthes Polycelis teniis Annelida Glossiphonia heteroclita Helobdella slagnalis Erpobdella octoculata Piscicola geometra Stylaria lacustris Naididae Tubificidae Molluscs Bithynia leachi B. tentaculata Lymnaea auricularis L . peregra Physa fontinalis Planorbis albus P. carinatus Vulva to piscinalis
Pisidium sp . Sphaerium sp .
Crustacea aq uaticus Gammarus pulex Side crystallina Ostracoda Hydracarina species a species b Insecta Caenis horaria
Asellus
C . moesta C . robusta Cloeon dipterum
Chironominae Orthocladiinae Tanypodinae Forcipomyia sp . Lepidoptera (larva) Dytiscidae (larvae) Sigara falleni
No . of animals
Non-towpath side
2
Dugesia
7 9 3 2 3 2 2
Glossiphonia heteroclita Helobdella stagnalis Hemiclepsis marginata Pisicola geometra
1 14 2
6 4 3 1. 5 3 22
38 7
tigrina
Tubificida
Bithynia tentaculata Lymnaea auricularia L. peregra
Physo fontinalis Planorbis albus P. carinatus Potamopyrgusjenhinsi Segmentina complantata Valvata piscinalis Anodonta cygnea Pisidiurn sp . Sphaerium sp . S . lacustre
Asellus
aquatic us Corophium curvispinurn
4 10
Ostracoda Simocephalus
24 1
species
36
Caenis horaria C . moestc
2
76 262 8 17 1 5 1 9 5
vetulus
C . robusta Cloeon dipterum
Chironominae Orthocladiinae Tanypodinae Sialis lutraria Dytiscidae (larvae) (adult) Haliplidae
No . of animals 5 11 15 1 3 23
8
2 4 5 3 25 1
81 17 1 17 3 14 50
33 4 47 20 2 8 13 11 2 1 5
129 TABLE 12 (continued) Towpath side
No . of animals
Non-towpath side
No . of animals
Corixidae (nymphs) Nepa cinerea Gerris laeustris Notonecta glauca Trichoptera species a species b Zygoptera
3 1 2 1 2 1 13
Elmidae Sigara distincta S. falleni Sigara nymphs Trichoptera species b others Zygoptera
1 7 4 33 7 7 6
From Baldock (1976) .
TABLE 13 Number of wetland species in the major plant and animal groups that are associated with the Grand Union Canal in Milton Keynes No . of species Flowering plants and ferns Dragonflies and damselflies (Odonata) Fish Small mammals Birds Phytoplankton Amphibians
59 7 13 3 20 134 1
Coenagrion puella, Enallagma cyathigerum, Ischnura elegans, Libellula quadrimaculata, and Sympetrum striolatum . For one species, L . quadrimaculata, it is the only breeding site (Parker and Halliday, 1979) . Three mammals, water shrew (N. fodiens), water vole (A . amphibius) and brown rat (Rattus norvegicus), occur in the canal (Dickenson, 1975) . A comparison of the numbers of fish and the biomass is given in Table 14 . The bird species associated with the canal are given in Table 4 . Fifty-nine species of higher aquatic plants have been found in the canal (Table 3) . The dominant species is Elodea canadensis, although Potamogeton pectinatus is dominant in the northern section (Tasker, 1980) . Juncus effusus, Sagittaria sagittifolia and Sparganium erectum are common but no one species is dominant throughout the length of the canal within the city . Smooth newt (T. vulgaris), a number of Coleoptera, Hemiptera, Hirudinea, platyhelminthes, Gammarus sp ., crayfish (A . pallipes), water spiders and eleven species of mollusca occur in the urban canals of the West Midlands (Teagle, 1978) .
1 30 TABLE 14 Numbers of fish and total weight (kg biomass) in the Grand Union Canal, Milton Keynes Species
Total numbers
Total weight (kg)
1974
1974
1979
2000 Bream (Abramis brama) Carp (Cyprinus carpio) Crucian Carp (Carassius carussius) Bullhead (Co ttus go bio) 580 280 Dace (Leuciscus leuciscus) 11 660 Gudgeon (Gobio gobio) Loach (Nemacheilus barbatura) Perch (Perca fluviatilis) 14660 Pike (Exo lucius) 1 540 Roach (Rutilus rutilus) 100 240 Rudd (Scardinius erythrophthalmus) 200 Ruff (Gymnocephalos cernua) 8 800 Tench (Tinca tinca)
6 557 547 1 093 2 551 2 551 5 466 1 640 34436 364 91 828 547 11 843 3 280
151 620
162 705
Total &Without carp weight .
Fig . 13 . Canal
he centre of Birmingham .
156 .16 6 .38 3 .40 194 .37 246 .14 483 .5 3290 .8 8 .20 155 .06 4544 .09
1979 1419 .4 2714 .0 79 .6 30 .2 58 .3 94 .3 14 .4 730 .4 161 .1 2354 .4 28.9 205 .6 290 .0 5455 .74
131
Fig. 14 . Canal, Leicester. Many people in Britain believe canals to be dangerous and because of this many canals have been modified . For example, the Rochdale Canal, Manchester, has been filled with concrete to leave a water depth of about 15 cm, resulting in the loss of a valuable natural resource for recreation, wildlife and amenity (Kelcey, 1978b) . The Greater London Council's scheme to improve 19 km of the Grand Union Canal in London concentrates on physical and recreational improvements ; the opportunities for wildlife have been overlooked or ignored (GLC, 1975) - see Fig . 13 . Although few canals are now used by commercial traffic, they are wellused by pleasure craft . The absence of boats leads to the development of a hydrosere and the eventual reduction in the aquatic wildlife . On the other hand, over-use results in the annihilation of aquatic plants and the consequential loss of other parts of the ecosystem . Heated industrial discharges into the St . Helens Canal, Lancashire, allow several tropical fish species to survive (Fig . 14) . MARSHES Marsh habitats can be divided into four types : fen (alkaline), neutral, bog (acid) and salt marsh . All four types occur in urban areas . Marsh represents an ecotone between water and dry land and because it is neither one nor the other it presents a number of maintenance problems : (a) it
1 32
looks untidy, especially in the autumn/winter and therefore gives the appearance of derelict land ; as a consequence it collects rubbish and becomes an eyesore ; (b) it is sensitive to changes in land drainage ; (c) changes in water quality can cause considerable changes in the vegetation ; (d) it is very difficult to manage, either chemically or mechanically . Merecroft, a marsh in Birmingham, contains a variety of plants including Caltha palustris, Stachys palustris, Filipendula ulmaria, Frangula alnus and Typha augustifolia . The vegetation of a species-rich marsh in Luton,
Bedfordshire, is described in Dony (1953) . The susceptibility of this site to the disturbances mentioned earlier is discussed in Davis (1976). Acid bogs are much less common than fen or neutral marsh in urban areas . Westfield Bog, which contains six species of Sphagnum, is one of the most interesting habitats within 20 km of London (Cole, 1980) . The bogs and pools of Sutton Park, Birmingham, contain a variety of acidloving plants, including Sphagnum spp ., Anagallis tenella, Drosera rotundifolia, Eriophorum angustifolium, E . aaginatum, Hydrocotyle vulgaris, Menyanthes trifoliata, Pedicularis palustris, Pinguicula vulgaris, Potentilla palustris, Ranunculus lingua, Viola palustris and Vaccinium oxycoccus .
Inland salt-marshes are scarce in Britain and not well documented . Wild brine streams and the extraction of salt for the chemical industry has produced localised saline soil and pools throughout the small towns in the Cheshire salt-field . An account of the vegetation of these areas is given in Lee (1975) ; Williams (1973) and Venables (1974) describe the vegetation of saline pools near Droitwich in the English Midlands . MANAGEMENT
Most urban water bodies over 30 cm deep are considered to be a public danger, and in many towns there is substantial public pressure to fill them in or at least fence them off. Ditches, streams and ponds attract rubbish and become eyesores, supermarket trollies breed in them, and anglers spend a lot of time and effort beating down the emergent vegetation . Responsibility for maintenance is diffuse . Water quality and flow is the responsibility of the water authorities whilst the banks are the responsibility of the landowner . Small streams, ponds and lakes are also the responsibility of the landowner whilst the British Waterways Board is responsible for the canals . Rivers, streams, ditches, dykes canals and estuaries pass through many different ownership and administrative boundaries, making consistency of management virtually impossible . This is exacerbated by the differing objectives of the various managing agencies . In order to improve the quality of urban water bodies for wildlife, two simultaneous operations are essential . First, it is necessary to establish an education programme aimed at politicians, professional and manual staff and the community at large . Local authorities in Britain generally lack the expertise to manage whole landscapes but especially the aquatic
1 33
element . They need to acquire this expertise if the landscape is going to make an impact and add to the quality of life. The community at large must understand, appreciate and care for their surroundings, otherwise the landscape will not survive . The second measure is technological : the improvement of existing water bodies for wildlife by some skillful ecological engineering ; for example, slackening the bank slopes, sculpting the edges, appropriate planting of terrestrial and aquatic plants, and the introduction of aquatic animals (invertebrates and vertebrates) . Greater efforts are also needed to exploit the opportunities to create new aquatic habitat (Kelcey, 1978a) . The initiative advocated by Newbold et al . (1983) in respect of nature conservation and river engineering is urgently required for urban watercourses . Once more it sadly reflects a missed opportunity . A management plan setting out the objectives, priorities, specification of works and the costs should be prepared for each water body . Such plans have been produced by the author for about 1000 ha of parkland (including ponds, lakes, streams, rivers and canals) in Milton Keynes . Where rivers and other linear water courses pass through several ownerships the plan must be agreed to by all interested parties . CREATION OF NEW WATER BODIES
Urban areas provide considerable opportunities to engineer the ecology of new and existing water bodies for wildlife, as a primary or a secondary interest (Kelcey, 1978a) . In some cases the rehabilitation must be done with great care . Apparent `derelict' sites may have a relatively rich flora and fauna that can easily be destroyed by well-meaning but ill-informed improvement . In many cases the opportunities are not comprehended or, if they are, ignored (Kelcey, 1978b) . Unfortunately the creation of habitats appears to be a phenomenon of new towns ; although similar opportunities exist in established towns and cities, they are generally not exploited, mainly because of the administrative problems and the lack of `will' . PLANNING AND DESIGN IN PRACTICE
The British planning system provides for a hierarchy of plans from regional plans to structure plans (which cover an administrative county of about 2000-3000 km') to local and district plans (which are concerned with a township or part of one). In addition, there is a subject plan, which deals with a specific subject, e .g. minerals . As far as the author is aware, there are no subject plans concerned with either water or nature conservation . Water generally receives superficial treatment in most aspects of local authority planning . This is mainly because it lies outside the remit of local
1 34
planning authorities . For example, land drainage and supply reservoirs are the responsibility of the water authorities, the canals are owned by the British Waterways Board whilst recreational and amenity lakes are in private ownership or the responsibility of the local authority's landscape maintenance department . Two examples of the treatment of water in planning and design are given below . One relates to a linear system (namely the canal network) of an established urban area, the second to a lake in a new town . Both are commendable but not typical of the treatment of water as a wildlife, recreational and visual resource in towns . West
Midlands
The West Midlands cover the densely urbanised and once heavily industrialised area of midland England . In 1980 the County Council produced a canal strategy (WMCC, 1980) . Although not a statutory planning document, it sets out in broad terms the Council's objectives for the treatment of about 240 km of canal in its area (Fig . 15)_ The strategy identifies the two major problems from which the canal network is suffering . Firstly, it is old and in poor condition . Secondly, about 30% of the derelict land in the County is adjacent to it . However, the Council recognises that most of the wildlife value results from underuse . Those lengths of subregional, district and local nature conservation value have been identified, although it points out that this value is being eroded by pollution, the dumping of rubbish and culverting . One of the 27 policy statements says that the Council will encourage the conservation and enhancement of the canal network as a wildlife habitat . In stating that "the canal network is an important environmental and recreational asset whose potential has yet to be realised", the Council recognises that successful implementation of its policies can only be achieved with the co-operation of a large number of organisations . To overcome the notorious difficulty that planning departments have in implementing their policies, the County Council has established a canal liaison committee to investigate means of doing so . It also says that it will work with the District Councils to protect the wildlife value of the canals . More recently, the Council has produced a nature conservation strategy (WMCC, 1984) ; again although not a statutory planning document, is provides guidelines for planning control and the preparation of plans . Amongst other things the strategy seeks to "protect and enhance a basic network of open space and wildlife corridors" . This has been achieved by identifying and designating three categories of land (including water features such as rivers, lakes, fen and bog) : (a) `Wildlife Reservoirs', which are large areas of good wildlife habitat ; (b) `Open Space/Wildlife Corridors', open spaces that link up with Wildlife Reservoirs of the countryside ; (c) `Links and Stepping Stones', canals, rivers and disused railways that act as links
135 between the Wildlife Reservoirs and Corridors . Stepping stones are good habitat areas of over 50 ha and which are located on the Links . The distinction between categories (b) and (c) is not at all clear. Whilst the policies contain references to aquatic systems, the implementation proposals concentrate on terrestrial systems . However, one special project termed `Operation Kingfisher' is a collaborative effort between statutory authorities and voluntary groups and is aimed at improving the wildlife quality of the River Cole and the land adjacent to it . Considerable emphasis is put (in both strategies) on implementations being carried out by voluntary organisations . This policy reflects the high correlation between the interest of urban local authorities in wildlife conservation and the availability of government funded employment, financial incentive schemes and the large pool of voluntary labour . A large part of the habitat survey work of the West Midlands, on which the strategy is based, was carried out by a voluntary organisation, education establishments and a government employment scheme . As laudable as these developments are, the foundation for the effective and long-term management of urban wildlife resources is very insecure, relying as it does on `voluntary' labour . Birmingham . The city of Birmingham is a component of the West Midlands (see Fig . 15) . In preparing its district plan for the central area, the City Council (BCC, 1984) has developed a policy for the improvement of public open space, including the canals (see Fig . 16 ; BCC, 1984) . In doing so it has been cognisant of the WMCC's canal strategy for the 1980's . The proposals include using the canals to link open space (to this end, the City Council has successfully negotiated a public right of access to the canal towpath with the British Waterways Board) and the tidying-up and landscaping of the towpaths and canalside areas . Although the proposals include a general statement about the intention to improve the condition of the canals themselves, nothing is said about their ecological condition nor of their actual or potential nature conservation value and what, if anything, needs to be done to protect, improve or create that value . As with the County Council's proposals success can only be ultimately measured by the extent and quality of the implementation . Milton Keynes
Most of the housing/water-front/public open space development in Britain has occurred alongside rivers and canals ; although as far as canals are concerned, the development has tended to be directed away from rather than towards water . It is rare to find housing that is directly adjacent to a lake sited in public open space . The development of the area around Lodge Lake, a 4 .72-ha wet balancing lake in the Loughton Valley of Milton Keynes, is an attempt to
1 36 KEY Birmingham City boundary Birmingham City centre J Canal net- . , '
akm
Fig . 15 . The canal network of the West Midlands, England .
N KEY Canal network and open space improvements - •' --Mayor marls
\
f 500 m
Fig . 16 . The canal system of Central Birmingham, England .
I
Conservalon Areas
137 KEY Inlets Park Housing
O Water Marsh Island
r
Hedge
i 100m
Fig . 17 . The planning and design of and around Lodge Lake, Milton Keynes . merge nature conservation, other recreational interests (e .g . angling and walking), major public open space and housing . A long, narrow island, created to retain the visual and wildlife qualities of a strong hedge and the course of the original stream, divides the lake in half (see Fig . 17) . The eastern half has a shallow, undulating margin with bays and pools whilst the western side has a steeper, straighter margin going into deeper water. The eastern, southern and northern sides lie in the valley park . On the west side there is housing with some gardens reaching the water's edge (Fig. 18) . A wide range of emergent and submerged aquatic plants have been planted, including Phragmites australis, Iris pseudacorus and Nymphaea alba, and the lake stocked with fish, e .g . bream (Abramis brama), roach (Rutilus rutilus) and tench
(Tinca
tinca) .
RESEARCH It is always easy to advocate more research and surveys to provide more information . The art of the landscape scientist/manager is to correctly identify the questions that need to be answered and then to formulate
138
Fig . 18 . Lodge Lake, Milton Keynes : wildlife to the left, housing to the right .
a research brief that will provide information on which he or she can make a wiser decision . The preparation of this paper has demonstrated the paucity of information about the ecology of urban ecosystems, especially compared with that of rural areas . The redistribution of resources to enable further studies to be made in urban areas is not unreasonable . The major problem with ecological research in the United Kingdom is that it is ad hoc and lacks both objectives and a programme . It is therefore desirable that the first step should be to assess what information is required to obtain a reasonable understanding of urban ecosystems and then to set out a programme through which those objectives could be achieved . The NERC's report Amenity grasslands - the need for research (NERC, 1977) goes someway along these lines but failed to establish a programme with financial targets . The priority of such a programme must be to provide a description of the extent and quality of the physical, chemical and biological aspects of urban ecosystems . More quantitative studies can follow . A description of the ecosystems is essential to formulate policy and as a base line for measuring change .
1 39 CONCLUSIONS
The variety of urban lakes and ponds is attributed to nine factors : size : < 1 m 2 to several hundreds of hectares ; age : from ephemeral storm pools to several hundreds of years ; depth : from a few millimetres to several metres ; in general urban water bodies are shallow, i .e. < 2 .0 m ; substratum : concrete to silt ; bank slope : vertical to about 1 : 20 ; edge shape : straight to well indented ; edge material : concrete to soil ; edge vegetation : overhanging vegetation varies from none to dense evergreen ; openness : the area of open water varies from 100% in large reservoirs to none in small eutrophic ponds . These factors are influenced by three others : (a) source and quality of water; (b) degree of management ; (c) degree of human disturbance, excluding management . As far as moving water is concerned, Haslam (1978) lists the most important physical variables as flow, substrate, width, depth, drainage order (where the watercourse is in the drainage system) and slope . Whilst more is known about bird communities and populations of urban water bodies than about any other group of organisms, the level of information is still poor . However, what there is indicates that many urban water bodies are or have the potential to be rich in wildlife, possibly richer than some of their rural counterparts . Because of the lack of information, planning, design and management, policies are weak or non-existent . Planning policies are concerned with broad principles and rely on voluntary labour for most of their implementation . Wildlife and wildlife habitats in towns and cities perform a variety of functions. They increase the amenity value and visual quality of the townscape and take pressure off the countryside by providing opportunities for education and recreation . However, urban watercourses are also under attack . Many people believe them to be dangerous and a hazard to health . Such pressures are exacerbated by the deposition of litter, vandalism, illegal shooting and egg collecting. Consequently landscape managers and engineers prefer to see them filled in or culverted . Urban areas provide great opportunities for the rehabilitation and creation of aquatic habitats ; ecological engineering can make many of the rarer species much more common . With increasing pressure on the rural environment and growing awareness of and interest in wildlife, it is probable that urban areas will have a major role in wildlife conservation in the future . The importance of urban areas for wildlife is not reflected in the Nature Conservancy Council's discussion document, Objectives and strategy for
140
nature conservation in Great Britain (Ratcliffe, 1983) . This document gives priority to the protection of elite sites in the rural environment and is constrained by a naturalist's philosophy of 40-50 years ago . It continues to propound an antiquated and inappropriate system, rather than seeking the imaginative and radical approach that is needed if development and nature conservation are to come to terms . The management of urban green space, and incorporation of development (which will always be necessary) into it, is a delicate art that requires knowledge about the extent, structure and function of urban ecosystems . ACKNOWLEDGEMENTS
I am most grateful to John Benson and Lesley Fairbank for their helpful comments on an earlier draft of the manuscript, and to Anne Robinson for her kindness in preparing Figs . 4 and 6 . G .S . Armstrong of Thames Water kindly provided additional information about the fish of London's supply reservoirs . N . Lewis supplied the list of plants of Martins Pond, Nottingham, Lesley Fairbank the list of algae in Table 2 . The following have allowed me to use published information : Anglian Water (parts of Tables 9 and 10), Birmingham City Council (Fig . 16), Biological Conservation (Fig . 5 and Table 5), Blackwell Scientific Publishers (Table 14), London Natural History Society (Tables 8 and 11), Milton Keynes Development Corporation (parts of Tables 9 and 10) and West Midlands County Council (Fig. 15) . Finally, I wish to acknowledge my debt to the poor and deprived of this country for many long and interesting conversations (in the most strange and unmentionable of places) which have sharpened my mind . REFERENCES Alderton, R .E ., 1977 . Birds at Surrey commercial docks, January 1973 to December 1975 . London Bird Rep ., 40 : 85-90 . Andrews, M .J ., 1977 . Observations on the fauna of the metropolitan river Thames during the drought in 1976 . London Nat., 56 : 44-56 . Aston, K .F .A . and Andrews, M .J., 1978 . Freshwater macroinvertebrates in London's rivers, 1970-77 . London Nat ., 57 : 34-52 . Baldock, B., 1976 . A survey of the freshwater invertebrates of the Grand Union Canal . Ecological Studies in Milton Keynes, 17 . Milton Keynes Development Corporation, 76 pp. Baldwin, P ., 1979 . Survey of the invertebrates of Coldharbour, Jubilee and Newfoundout pits . Ecological Studies in Milton Keynes, 48 . Milton Keynes Development Corporation, 61 pp . Barnes, L .E . and Logan, P., 1977 . Survey of the freshwater invertebrates of Fletton's pits . Ecological Studies in Milton Keynes, 25 . Milton Keynes Development Corporation, 26 pp . Batten, L ., 1977 . Sailing on reservoirs and its effect on water birds . Biol . Conserv ., 11 : 49-58. BCC, 1984 . Birmingham Central Area District Plan . Birmingham City Council, Birmingham, 49 pp .
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142 Lee, R .L .G ., 1977 . The Serpentine fish and theirr parasites . London Nat ., 56 : 57-70 . MKDC, 1975 . Biological Surveys of the Ouse and Ouzel 1971-74 . Ecological Studies in Milton Keynes, 14 . Milton Keynes Development Corporation, 76 pp. MKDC, 1977 . Biological Surveys of the Ouse and Ouzel 1975-77 . Ecological Studies in Milton Keynes, 24 . Milton Keynes Development Corporation, 68 pp . Moffatt, D ., 1973 . Bridgewater : ecological assessment . Warrington Development Corporation, Warrington, England, 70 pp . NERC, 1977 . Amenity grasslands - the need for research . Natural Environment Research Council, London, 64 pp . Newbold, C ., Purseglove, J . and Holmes, N ., 1983. Nature conservation and river engineering. Nature Conservancy Council, London, 36 pp . Numata, M . (Editor), 1983 . Water oriented urban ecosystem studies, I . Environ . Sci. Res . Rep . B175-R15-1, Chiba University, Japan, 138 pp . Numata, M . (Editor), 1984 . Water oriented urban ecosystem studies, II . Environ . Sci. Rep . B211-R15-3, Chiba University, Japan, 133 pp . Parker, D .M . and Holliday, R .J ., 1979 . Survey of dragonflies . Ecological Studies in Milton Keynes, 40 . Milton Keynes Development Corporation, 58 pp . Pentelow, F .T .K ., 1965. The lake in St . James's Park. London Nat ., 44 : 128-138 . Ratcliffe, D ., 1983 . Objectives and strategy for nature conservation in Great Britain - a discussion document . Nature Conservancy Council, London, 44 pp . Sheldon, J ., 1976 . Biological survey of the Union Canal . Lothian Regional Council, Edinburgh, 30 pp . Simms, E ., 1974 . Wildlife in the Royal Parks . HMSO, London, 47 pp. Speak, N .J ., Peers, C .J. and Bingham, S .V ., 1975 . The birds of Edgbaston Park Nature Reserve . Proc . Birmingham Nat . Hist . Soc ., 23 : 31-36 . Sukopp, H . and Murkstein, B ., 1980 . Die Ufervegetation der Berliner Havel 1968-77. Garten Landschaft, 80(1) : 30-36 . Tansley, W .G ., 1965 . The British Islands and their Vegetation . Cambridge University Press, Cambridge, 484 pp . Tasker, A ., 1980 . A survey of the macrophytes of the Grand Union Canal . Ecological Studies in Milton Keynes, 55 . Milton Keynes Development Corporation, 39 pp. Teagle, W .G ., 1978 . The endless village . Nature Conservancy Council, Shrewsbury, 58 pp . Venables, A ., 1974 . Vegetation of Upton Warren, Droitwich . Diss ., Department of Plant Biology, University of Birmingham (unpublished) . Weyl, R ., 1978 . Irvine New Town. Wildlife Survey, Vols . 1 and 2- Irvine Development Corporation, Irvine, Scotland, 55 + 106 pp . Wheeler, A ., 1979 . The Tidal Thames - The History of a River and its Fishes . Routledge and Kegan, London, 228 pp . Williams, J .T., 1973 . A preliminary survey of salt-tolerant vegetation near Droitwich . Proc. Birmingham Nat . Hist . Soc ., 22 : 185-190WMCC, 1980 . A Canal strategy for the 1980s, West Midlands County Council, Birmingham, 29 pp . WMCC, 1984 . The Nature Conservation Strategy for the West Midlands. West Midlands County Council, Birmingham, 60 pp . Woodiwiss, S.S ., 1964 . The biological system of stream classification used by the Trent River Board . Chem . Ind ., 11 : 443-447 . Yalden, D ., 1965 . Distribution of reptiles and amphibians in the London area . London Nat ., 44 : 57-69 .