Igelbäcken
Encyclopedia
Igelbäcken is a small stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...

 in northern Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

. The drainage area, part of the national park Ekoparken
Ekoparken
The Royal National City Park is the world's first National City Park, established in 1995 in the municipalities of Stockholm, Solna and Lidingö in Sweden.1/ km²2/ Population per km²- Pictures :Some places in "The Eco Park"....

 and divided into several nature reserves, is shared by the municipalities of Järfälla, Sollentuna, Solna
Solna Municipality
Solna Municipality is a municipality in Stockholm County in east central Sweden, located just north of the capital Stockholm. Its seat is located in the 'city' of Solna....

, Stockholm, and Sundbyberg.

Watershed

Stretching more than 10 kilometres west to east from Säbysjön in Järfälla to Edsviken
Edsviken
Edsviken is an elongated, narrow inlet of the Baltic Sea running through the Swedish municipalities of Danderyd, Solna and Sollentuna. Edsviken ranges from Stocksund and Bergshamra in the south to Edsberg in the north. The inlet is about long with an area of approximately ; its maximum depth is...

 near the Ulriksdal Palace
Ulriksdal Palace
Ulriksdal Palace is a royal palace situated on the banks of the Edsviken in the National City Park in Solna, 6 km north of Stockholm. It was originally called Jakobsdal after its owner Jacob De la Gardie, who had it built by architect Hans Jacob Kristler in 1643-1645 as a country retreat...

, Igelbäcken's main feeder is the stream Djupanbäcken carrying water from the small lake Djupan. Due to the location in the national park, its untouched character, and to the rare population of Stone Loach
Stone Loach
The Stone loach, Barbatula barbatula, is a species of ray-finned fish in the Balitoridae family.It is found in Austria, Belarus, Belgium, Bulgaria, China, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Japan, North Korea, South Korea, Latvia, Liechtenstein,...

, Igelbäcken is considered one of the most valuable water bodies in Stockholm. Nevertheless, samples taken in 2001 showed levels of phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 were moderate while levels of metals were increasing between the stream's origin and mouth. The municipalities sharing the catchment area, together with the county administrative board have initiated various project to enhance the natural value of the river and the surrounding green areas. For example, in 2006 Solna and Sundbyberg declared their ambitions to transform the central part of the stream from a straight ditch to a meandering river murmuring over stones, overshadowed by trees and flanked by wetlands intended to attract amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s and wader
Wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...

s; a project partly financed by the Swedish state.

The upper part of the watershed is constituted of Norra Järvafältet, an open-air area characterized by moraine
Moraine
A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have...

 ridges covered with forests separated by water meadows and tilled fields. While some 20 hectares of the surrounding area is used for pasture, the stream is bordered by deciduous plants such as Alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

 and Birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...

 and Bulrush
Typha latifolia
Typha latifolia is a perennial herbaceous plant in the genus Typha. It is found as a native plant species in North and South America, Europe, Eurasia, and Africa...

 can be found in non-shadowed patches. Some 2,5 kilometres from its origin, the stream passes down in a culvert under a traffic route (Akallavägen) and the Barkarby Airport
Barkarby Airport
Barkarby Airport was a disbanded Swedish Air Force base, near Akalla north of Stockholm used for general aviation. Barkarby Airport was one of Sweden’s oldest active airports until it was closed in 2010. A large shopping complex is still situated close to – and partly on – the airfield. Current...

 before merging with the stream Djupanbäcken. This part of the catchment area contains a motocross
Motocross
Motocross is a form of motorcycle sport or all-terrain vehicle racing held on enclosed off road circuits. It evolved from trials, and was called scrambles, and later motocross, combining the French moto with cross-country...

 track, a golf driving range
Driving range
A driving range is an area where golfers can practice their swing. It can also be a recreational activity itself for amateur golfers or when enough time for a full game is not available. Many golf courses have a driving range attached and they are also found as stand-alone facilities, especially...

, a closed dump, and receives stormwater from the E18
E18
E18 or E-18 may be:* E18 error, a Canon digital camera error code* County Route E18 , a County route in California* DRG Class E 18, a class of German electric locomotives* European route E18* E18, a postcode district in the E postcode area...

 traffic route. Thereafter, the stream flows some 4 km in the valley separating the suburbs Akalla
Akalla
Akalla is a district in Rinkeby-Kista borough, Stockholm, Sweden. Akalla has 8,153 inhabitants as of December 31, 2007, in which immigrants, mostly from Asia, make up 64 % of the population....

-Hjulsta
Hjulsta
Hjulsta is a working-class suburb of Stockholm. It is considered being part of Tensta, but with its own subway station which was opened in 1975 and is the end station of the blue line....

 and Tensta
Tensta
Tensta is a district in Spånga-Tensta borough, Stockholm, Sweden. There are about 6,000 apartments in Tensta and a population of 17,083 as of December 31, 2007....

-Rinkeby
Rinkeby
Rinkeby is a district in Rinkeby-Kista borough, Stockholm, Sweden. Rinkeby had 15,051 inhabitants as at December 31, 2007.Rinkeby is noted for its high concentration of immigrants and people with immigrant ancestry...

 and where are several rural structures including an ecological farm (Hästa Gård), eight allotment-gardens
Allotment (gardening)
An allotment garden, often called simply an allotment, is a plot of land made available for individual, non-professional gardening. Such plots are formed by subdividing a piece of land into a few or up to several hundreds of land parcels that are assigned to individuals or families...

, and some minor overgrown wetlands. East of the valley the river is crossed by a second traffic route (Kymlingelänken) before flowing 2,5 km through an open grassland to reach a railway and the E4
European route E4
European route E 4 passes from north to south through Sweden from the border with Finland, total length . The Finnish part lies entirely within Tornio in northern Finland, and is actually only long...

 traffic route, water from the latter treated in a local cleaning plant. The last 1.4 km passes more allotment-gardens and the gardens of the Ulriksdal Palace
Ulriksdal Palace
Ulriksdal Palace is a royal palace situated on the banks of the Edsviken in the National City Park in Solna, 6 km north of Stockholm. It was originally called Jakobsdal after its owner Jacob De la Gardie, who had it built by architect Hans Jacob Kristler in 1643-1645 as a country retreat...

 before jumping into Edsviken through a low dam.

Environmental influence

In the early 1970s, the stream lost almost a third of its watershed below lake Säbysjön in connection with the construction of a drainage system for the surrounding suburbs. Water leaking into the stormwater
Stormwater
Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...

 tunnel further diminishes the inflow of groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

. Furthermore, a by-product of the construction of these suburbs were the contaminated tips still located in the catchment area. Though the inflow from Lake Säbysjän remains poorly documented, the lake is known to be rich in nutrients and consequently levels of phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 are high in the stream. Below the lake, the drainage area itself brings 120 kg/year of phosphorus and 3.300 kg/year of nitrogen, most of which comes from unsettled and cultivated terrain, a leakage reduced by keeping uncultivated zones next to the watercourse. Contributions of metals, such as zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, are brought to the stream from the surround open terrain and the landfill deposits in the catchment area. While levels of cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...

, copper, zinc, and nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 were reported as increased in ditches draining these deposits, levels of oil, PCB
Polychlorinated biphenyl
Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...

, and chlorinated hydrocarbons
Organochloride
An organochloride, organochlorine, chlorocarbon, chlorinated hydrocarbon, or chlorinated solvent is an organic compound containing at least one covalently bonded chlorine atom. Their wide structural variety and divergent chemical properties lead to a broad range of applications...

 were reported as insignificant.

Flora and fauna

Major stands of Greater Spearwort
Ranunculus
Ranunculus is a large genus of about 600 species of plants in the Ranunculaceae. Members of the genus include the buttercups, spearworts, water crowfoots and the lesser celandine....

 are found in the central valley with minor occurrences both up- and downstream. Next to the poor running waters near Ulriksdal Palace are Intermediate Water-starwort
Callitriche
Callitriche is a genus of largely aquatic plants known as water-starworts. Previously, it was the only genus in the family Callitrichaceae. However, according to the APG II system this family is now included in the Plantaginaceae...

 and further upstream two metre tall Great Willowherb
Epilobium
Epilobium is a genus in the family Onagraceae, containing about 160-200 species of flowering plants with a worldwide distribution. They are generally abundant in the subarctic, temperate and subantarctic regions, whereas in the subtropics and tropics they are restricted to the cool montane biomes,...

 is found along the shores as is instances of Blue Water-Speedwell
Veronica (plant)
Veronica is the largest genus in the flowering plant family Plantaginaceae, with about 500 species; it was formerly classified in the family Scrophulariaceae...

. Some rare plants along the stream include Greater Pond-sedge
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...

, Greater Pond-sedge
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...

, True Fox-Sedge
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...

, and Cyperus-like Sedge.

Samples of bottom fauna near the palace in 1994 documented an abundance of species of Oligochaeta
Oligochaeta
Oligochaeta is a subclass of animals in the biological phylum Annelida, which is made up of many types of aquatic and terrestrial worms, and this includes all of the various earthworms...

, including a new species, Fridirica ulrikae. Rake samples in 1998 documented more than a hundred species, a biodiversity explained by the oxygen feed produced by increased water flow that year, most of whom were insensitive to pollution. Two species considered Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...

 were also documented (the caddisfhly
Trichoptera
The caddisflies are an order, Trichoptera, of insects with approximately 12,000 described species. Also called sedge-flies or rail-flies, they are small moth-like insects having two pairs of hairy membranous wings...

 Trichoeochiton fagessi and the freshwater gastropod Aplexa hypnorum
Aplexa hypnorum
Aplexa hypnorum, common name the moss bladder snail, is a species of small air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Physidae, a family which are sometimes known as the bladder snails....

).

One of the most notable species in the stream is the rare Loach
Loach (fish)
Cobitidae is the family of the true loaches, which are Old World freshwater fish. They occur throughout Eurasia and in Morocco, and inhabit riverine ecosystems. Today, most "loaches" are placed in other families...

 species Stone Loach
Stone Loach
The Stone loach, Barbatula barbatula, is a species of ray-finned fish in the Balitoridae family.It is found in Austria, Belarus, Belgium, Bulgaria, China, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Japan, North Korea, South Korea, Latvia, Liechtenstein,...

 (Barbatula barbatula) attracted by the strong current and stony bottom of the stream. During dry periods sections of Igelbäcken dry up which is the most important threat to the fish. While its presence in the stream is still considered as threatened, the numbers of individuals increased during the period 1999-2001. Other fishes in the stream include Perch
Perch
Perch is a common name for fish of the genus Perca, freshwater gamefish belonging to the family Percidae. The perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning spotted, and the...

, Northern Pike
Northern Pike
The northern pike , is a species of carnivorous fish of the genus Esox...

, Roach
Rutilus
Rutilus is a genus of fishes in the family Cyprinidae, commonly called roaches. Locally, the name "roach" without any further qualifiers is also used for particular species, particularly the Common Roach Rutilus (Latin for "shining, red, golden, auburn") is a genus of fishes in the family...

, Tench
Tench
The tench or doctor fish is a freshwater and brackish water fish of the cyprinid family found throughout Eurasia from Western Europe including the British Isles east into Asia as far as the Ob and Yenisei Rivers. It is also found in Lake Baikal...

, Crucian carp
Crucian carp
The crucian carp is a member of the family Cyprinidae, which includes many other fish, such as the common carp, or the smaller minnows. They inhabit lakes, ponds, and slow-moving rivers throughout Europe and Asia. The crucian is a medium-sized cyprinid, which rarely exceeds a weight of over 3.3...

, and, more rarely, Trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...

. European crayfish
Astacus astacus
Astacus astacus, the European crayfish, noble crayfish or broad-fingered crayfish, is the most common species of crayfish in Europe, and a traditional foodstuff. Like other crayfish, Astacus astacus is restricted to fresh water, living only in unpolluted streams, rivers and lakes...

 was observed in 1989 and Signal crayfish
Signal crayfish
The signal crayfish, Pacifastacus leniusculus, is a North American species of crayfish. It was introduced to Europe in the 1960s to supplement the Scandinavian Astacus astacus fisheries, which were being damaged by crayfish plague, but the imports turned out to be a carrier of that disease...

, illegally introduced during the 1990s, is feared to threaten the population of Stone Loach and to bring crayfish plague
Crayfish plague
Crayfish plague, Aphanomyces astaci, is a water mould that infects crayfish, most notably the European Astacus which dies within a few weeks of being infected...

 into the stream.

Numerous birds, such as Thrush Nightingale
Thrush Nightingale
The Thrush Nightingale, Luscinia luscinia , is a small passerine bird that was formerly classed as a member of the thrush family Turdidae, but is now more generally considered to be an Old World flycatcher, Muscicapidae...

, Common Snipe
Common Snipe
The Common Snipe is a small, stocky wader native to the Old World. The breeding habitat is marshes, bogs, tundra and wet meadows throughout northern Europe and northern Asia...

, and Eurasian Woodcock
Eurasian Woodcock
The Eurasian Woodcock, Scolopax rusticola, is a medium-small wading bird found in temperate and subarctic Eurasia. It has cryptic camouflage to suit its woodland habitat, with reddish-brown upperparts and buff-coloured underparts...

, breed along the stream, and species feeding in and around it include White-throated Dipper
White-throated Dipper
The White-throated Dipper , also known as the European Dipper or just Dipper is an aquatic passerine bird found in Europe, Middle East, Central Asia and the Indian Subcontinent. The species is divided into several subspecies, based primarily on colour differences, particularly of the pectoral band...

, Herons
Ardea (genus)
Ardea is a genus of herons. Linnaeus named this genus as the Great Herons, referring to the generally large size of these birds, typically 80–100 cm or more in length....

, and Lesser Spotted Woodpecker
Lesser Spotted Woodpecker
The Lesser Spotted Woodpecker is a member of the woodpecker family Picidae. It is assigned to the genus Dendrocopos ....

. The cultivated grounds located along the central reach of the stream attract species such as Long-eared Owl
Long-eared Owl
The Long-eared Owl - Asio otus is a species of owl which breeds in Europe, Asia, and North America. This species is a part of the larger grouping of owls known as typical owls, family Strigidae, which contains most species of owl...

, Common Kestrel
Common Kestrel
The Common Kestrel is a bird of prey species belonging to the kestrel group of the falcon family Falconidae. It is also known as the European Kestrel, Eurasian Kestrel, or Old World Kestrel. In Britain, where no other brown falcon occurs, it is generally just called "the kestrel".This species...

, Red-backed Shrike
Red-backed Shrike
The Red-backed Shrike is a carnivorous passerine bird and member of the shrike family Laniidae.English common names include 'Wariangle' and 'worrier'.-Description:...

, Whinchat
Whinchat
The Whinchat Saxicola rubetra is a small migratory passerine bird breeding in Europe and western Asia and wintering in Africa.Its scientific name means "small rock-dweller", in reference to its habitat...

, and Skylark
Skylark
The Skylark is a small passerine bird species. This lark breeds across most of Europe and Asia and in the mountains of north Africa. It is mainly resident in the west of its range, but eastern populations are more migratory, moving further south in winter. Even in the milder west of its range,...

. Goshawk breed in the surrounding pine forests.

No inventory of amphibians has been made in the stream itself, but most species common to the Stockholm area have been documented in the surrounding area with an abundant number of European viper
Vipera berus
Vipera berus, the common European adder or common European viper, is a venomous viper species that is extremely widespread and can be found throughout most of Western Europe and all the way to Far East Asia. Known by a host of common names including Common adder and Common viper, adders have been...

s. Four species of bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s were documented in 1197 near the central part of the stream: Whiskered bat
Whiskered bat
The whiskered bats Myotis mystacinus and related species, are small European bats with long fur. Although uncommon, M. mystacinus is often found around human habitation and around water; it is similar to Brandt's bat Myotis brandtii, from which it was distinguished as a separate species only in...

, Common Noctule
Common Noctule
The Common Noctule is a species of bat common throughout Europe, Asia, and North Africa. The UK distribution can be found on the National Biodiversity Network website ....

, Common Pipistrelle
Common Pipistrelle
The Common Pipistrelle Pipistrellus pipistrellus is a small pipistrelle bat whose very large range extends across most of Europe, North Africa, southwestern Asia, and possibly into Korea. It is one of the most common bat species in the British Isles....

, and Northern Bat
Northern Bat
The Northern Bat is a species of bat. An adult Northern Bat has a body length of 4.9-6.6 cm, a tail of 3.2-5.1 cm, and a wing length of 4.1-5.1 cm. The species is found across Europe and Asia, from England to Hokkaidō and south to northern India.-References: 2006 IUCN Red List of Threatened...

.
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