Orlången is a

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in central

Huddinge Municipality Huddinge Municipality ( sv, Huddinge kommun) is a municipality in Stockholm County, east central Sweden. Its seat is located in Huddinge (), which is a part of Stockholm urban area. The municipality is, with its approximately 110,000 inhabitants, ...

, just south of

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

. Orlången, one of the lakes in the Tyresån Lake System, forms part of the Orlången Nature Reserve.Huddinge Municipality, ''Orlången'', site

Catchment area

The catchment area is composed of criss-crossing fractured valleys with alternating agricultural lands and forests. The lake and its shores are highly popular for open-air activities such as fishing, bathing, birdwatching,

tour skating Tour skating is recreational long distance ice skating on natural ice. It is particularly popular in the Netherlands and the Nordic countries. It is becoming more popular in areas of North America such as New England, Southcentral Alaska, and Nov ...

, canoeing, skiing, and walking. The Bottnen ("The Bottom") wetland near the inflow from Mörtsjön is an important bird locale. There are several public baths by the lake, but its many cliffs are also popular spots to spend a summer day. Approximately half of the lake is available for angling for people with the required angling card.

Environmental impact

Though the mud-filled valleys surrounding Orlången originally made it moderately

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplank ...

, extended accumulation of nutrients from neighbouring populated areas has made it highly eutrophic. The deepest areas of the lake are depleted of oxygen during both winters and summers, which can indicate that internal loads are worsening the situation; the lake is possibly self-fertilising, as nutrients are released from its sediments. The present discharge of

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

, mostly deriving from three residential areas by the lake, is still too high although it remains controllable.

Flora and fauna

Aquatic plants includes

reed Reed or Reeds may refer to: Science, technology, biology, and medicine * Reed bird (disambiguation) * Reed pen, writing implement in use since ancient times * Reed (plant), one of several tall, grass-like wetland plants of the order Poales * ...

, club-rush, wood club-rush, broadleaf cattail,

flowering rush ''Butomus'' is the only known genus in the plant family Butomaceae, native to Europe and Asia. It is considered invasive in some parts of the United States. Taxonomy The Butomaceae family has been recognized by most taxonomists as a plant ...

water hemlock ''Cicuta'', commonly known as water hemlock, is a genus of four species of highly poisonous plants in the family Apiaceae. They are perennial herbaceous plants which grow up to tall, having distinctive small green or white flowers arranged in ...

yellow iris ''Iris pseudacorus'', the yellow flag, yellow iris, or water flag, is a species of flowering plant in the family Iridaceae. It is native to Europe, western Asia and northwest Africa. Its specific epithet ''pseudacorus'' means "false acorus", ref ...

, yellow loosestrife, bittersweet, yellow water-lily, white water-lily, broad-leaved pondweed, red pondweed, whorled water-milfoil, amphibious bistort,

water-soldier ''Stratiotes'' is a genus of submerged aquatic plant commonly known as water soldiers, described as a genus by Linnaeus in 1753. Several specific names have been coined within the genus, but at present only one is recognized: '' Stratiotes aloid ...

, frogbit,

duckweed Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose ...

, greater bladderwort, and

greater duckweed ''Spirodela polyrhiza'' ( ''S. polyrrhiza'') is a species of duckweed known by the common names common duckmeat, greater duckweed, great duckmeat, common duckweed, and duckmeat. It can be found nearly worldwide in many types of freshwater habitat ...

. Along the shores of the lake are hybrid crack willow,

alder Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...

, bay willow,

grey willow Grey willow or gray willow may refer to: *'' Salix atrocinerea'', a species of willow native to Europe commonly called grey willow *'' Salix cinerea'', a species of willow native to Europe and western Asia, also occasionally called grey sallow *''S ...

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China ...

ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...

purple-loosestrife ''Lythrum salicaria'' or purple loosestrifeFlora of NW Europe''Lythrum salicaria'' is a flowering plant belonging to the family Lythraceae. It should not be confused with other plants sharing the name loosestrife that are members of the family P ...

marsh fern ''Thelypteris palustris'', the marsh fern, or eastern marsh fern, is a species of fern native to eastern North America and across Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily ...

wild angelica ''Angelica sylvestris'' or wild angelica is a species of flowering plant, native to Europe and central Asia. An annual or short-lived perennial growing to a maximum of , it has erect purplish stems and rounded umbels of minuscule white or pale p ...

, marsh woundwort, gypsywort, creeping spearwort,

marsh cinquefoil ''Comarum palustre'' ( syn. ''Potentilla palustris''), known by the common names purple marshlocks, swamp cinquefoil and marsh cinquefoil, is a common waterside shrub. It has a circumboreal distribution, occurring throughout North America, Europe ...

, marsh-marigold, bittersweet,

skullcap Skullcap or skull cap usually refers to various types of headgear. Specifically it may refer to: Headwear * Beanie (seamed cap) * Biretta, forming part of some clerical, academic or legal dress * Calotte (Belgium), a skullcap worn by students at ...

corn mint ''Mentha arvensis'', the corn mint, field mint, or wild mint, is a species of flowering plant in the mint family Lamiaceae. It has a circumboreal distribution, being native to the temperate regions of Europe and western and central Asia, east t ...

, meadowsweet, trifid bur-marigold, and purple small-reed. An inventory of

dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...

in the north-eastern end of the lake documented a presence of

red-eyed damselfly ''Erythromma najas'', the red-eyed damselfly, is a member of the Coenagrionidae family of damselfly, damselflies. Appearance The species is a small damselfly, long, predominantly black with iridescent blue markings. The male resembles blue-tai ...

, northern damselfly,

azure damselfly The azure damselfly (''Coenagrion puella'') is a species of damselfly found in most of Europe. It is notable for its distinctive black and blue colouring. They are commonly found around ponds and lakesides during the summer. Morphology Adults ...

brown hawker The brown hawker (''Aeshna grandis'') is a large dragonfly about long. It is a distinctive species and is easily recognised, even in flight, by its brown body and bronze wings. At rest, blue spots on the second and third segments of the male' ...

club-tailed dragonfly The Gomphidae are a family of dragonflies commonly referred to as clubtails or club-tailed dragonflies. The family contains about 90 genera and 900 species found across North and South America, Europe, Asia, and Australia. The name refers to the ...

downy emerald The downy emerald (''Cordulia aenea'') is a species of dragonfly. It is metallic green and bronze in color, and its thorax is coated with fine hairs, hence its name. Like most other emeralds, the downy emerald has bright shiny green eyes. Adults ...

, and four-spotted chaser. Fishes present in the lake include

smelt Smelt may refer to: * Smelting, chemical process * The common name of various fish: ** Smelt (fish), a family of small fish, Osmeridae ** Australian smelt in the family Retropinnidae and species ''Retropinna semoni'' ** Big-scale sand smelt ''At ...

pike Pike, Pikes or The Pike may refer to: Fish * Blue pike or blue walleye, an extinct color morph of the yellow walleye ''Sander vitreus'' * Ctenoluciidae, the "pike characins", some species of which are commonly known as pikes * ''Esox'', genus of ...

roach Roach may refer to: Animals * Cockroach, various insect species of the order Blattodea * Common roach (''Rutilus rutilus''), a fresh and brackish water fish of the family Cyprinidae ** ''Rutilus'' or roaches, a genus of fishes * California roach ...

rudd ''Scardinius'' is a genus of ray-finned fish in the family Cyprinidae commonly called rudds. Locally, the name "rudd" without any further qualifiers is also used for individual species, particularly the common rudd (''S. erythrophthalmus''). Th ...

tench The tench or doctor fish (''Tinca tinca'') is a fresh- and brackish-water fish of the order Cypriniformes found throughout Eurasia from Western Europe including the British Isles east into Asia as far as the Ob and Yenisei Rivers. It is also ...

bleak Bleak may refer to: Fish * Species of the genus '' Alburnus'' * '' Alburnoides bipunctatus'', also known as the schneider Music * "Bleak", a song by Opeth from '' Blackwater Park'' * "Bleak", a song by Soulfly from '' Dark Ages'' Other uses * B ...

, silver bream,

carp bream The common bream, freshwater bream, bream, bronze bream, carp bream or sweaty bream (''Abramis brama''), is a European species of freshwater fish in the family Cyprinidae. It is now considered to be the only species in the genus ''Abramis''. ...

crucian carp The crucian carp (''Carassius carassius'') is a medium-sized member of the common carp family Cyprinidae. It occurs widely in northern European regions. Its name derives from the Low German ''karusse'' or ''karutze'', possibly from Medieval Lat ...

burbot The burbot (''Lota lota'') is the only gadiform (cod-like) freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments di ...

perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...

zander The zander (''Sander lucioperca''), sander or pikeperch, is a species of ray-finned fish from the family Percidae, which includes the perches, ruffes and darters. It is found in freshwater and brackish habitats in western Eurasia. It is a popul ...

, and

ruffe The Eurasian ruffe (''Gymnocephalus cernua''), also known as ruffe or pope, is a freshwater fish found in temperate regions of Europe and northern Asia. It has been introduced into the Great Lakes of North America, reportedly with unfortuna ...

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 North European ''Astacus astacus'' fisheries, which were being damaged by crayfish plague, but ...

were introduced in the 1970s. Common birds include

great crested grebe The great crested grebe (''Podiceps cristatus'') is a member of the grebe family of water birds noted for its elaborate mating display. Taxonomy The great crested grebe was formally described by the Swedish naturalist Carl Linnaeus in 1758 in t ...

mute swan The mute swan (''Cygnus olor'') is a species of swan and a member of the waterfowl family Anatidae. It is native to much of Eurosiberia, and (as a rare winter visitor) the far north of Africa. It is an introduced species in North America, home ...

Canada goose The Canada goose (''Branta canadensis''), or Canadian goose, is a large wild goose with a black head and neck, white cheeks, white under its chin, and a brown body. It is native to the arctic and temperate regions of North America, and it is o ...

mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...

water rail The water rail (''Rallus aquaticus'') is a bird of the Rallidae, rail family which breeds in well-vegetated wetlands across Europe, Asia and North Africa. Northern and eastern populations are bird migration, migratory, but this species is a perma ...

osprey The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...

marsh harrier The marsh harriers are birds of prey of the harrier subfamily. They are medium-sized raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. They are found almost worldwide, excluding ...

northern lapwing The northern lapwing (''Vanellus vanellus''), also known as the peewit or pewit, tuit or tew-it, green plover, or (in Ireland and Britain) pyewipe or just lapwing, is a bird in the lapwing subfamily. It is common through temperate Eurosiberia. ...

sandpiper Sandpipers are a large family, Scolopacidae, of waders. They include many species called sandpipers, as well as those called by names such as curlew and snipe. The majority of these species eat small invertebrates picked out of the mud or soil. ...

tern Terns are seabirds in the family Laridae that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated as a subgroup of the family Laridae which includes gulls and skimmers and consists of e ...

gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...

long-tailed tit The long-tailed tit (''Aegithalos caudatus''), also named long-tailed bushtit, is a common bird found throughout Europe and the Palearctic. The genus name ''Aegithalos'' was a term used by Aristotle for some European tits, including the long-tail ...

lesser spotted woodpecker The lesser spotted woodpecker (''Dryobates minor'') is a member of the woodpecker family Picidae. It was formerly assigned to the genus ''Dendrocopos'' (sometimes incorrectly spelt as ''Dendrocopus''). Some taxonomic authorities continue to list ...

reed warbler The ''Acrocephalus'' warblers are small, insectivorous passerine birds belonging to the genus ''Acrocephalus''. Formerly in the paraphyletic Old World warbler assemblage, they are now separated as the namesake of the marsh and tree warbler f ...

sedge warbler The sedge warbler (''Acrocephalus schoenobaenus'') is an Old World warbler in the genus '' Acrocephalus''. It is a medium-sized warbler with a brown, streaked back and wings and a distinct pale supercilium. Sedge warblers are migratory, crossing ...

marsh warbler The marsh warbler (''Acrocephalus palustris'') is an Old World warbler currently classified in the family Acrocephalidae. It breeds in temperate Europe and the western Palearctic and winters mainly in southeast Africa. It is notable for incorpora ...

, and

thrush nightingale The thrush nightingale (''Luscinia luscinia''), also known as the sprosser, 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, Muscic ...

. Additionally, a couple of cranes has been breeding by the lake for about ten years. The

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

forest north of the lake and the shallow reeds there is an important

biotope A biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. ''Biotope'' is almost synonymous with the term "habitat", which is more commonly used in English-speaking countrie ...

for

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

s, as the area produces a plenitude of insects while offering favourable milieux for hibernation. Inventories during the 1990s have documented a presence of

northern bat The northern bat (''Eptesicus nilssonii'') is the most abundant species of bat in northern Eurasia occurring from England to Hokkaidō and south to northern India. Description The northern bat is dark brown or black with some gold touched at th ...

parti-coloured bat The parti-coloured bat or rearmouse (''Vespertilio murinus'') is a species of vesper bat that lives in temperate Eurasia, from Western and Southern Europe, eastwards over the Caucasus and Iran into Mongolia, north-east China, Korea, Afghanistan a ...

Daubenton's bat Daubenton's bat or Daubenton's myotis (''Myotis daubentonii'') is a Eurasian bat with rather short ears. It ranges from Ireland to Japan (Hokkaido) and is considered to be increasing its numbers in many areas. This bat was first described in 181 ...

noctule ''Nyctalus'' is a genus of vespertilionid bats commonly known as the noctule bats. They are distributed in the temperate and subtropical areas of Europe, Asia and North Africa. There are eight species within this genus: * Birdlike noctule, ''N ...

soprano pipistrelle The soprano pipistrelle (''Pipistrellus pygmaeus'') is a small species of bat. It is found in Europe and often roosts on buildings. Taxonomy Until 1999, the soprano pipistrelle was considered as conspecific with the common pipistrelle The co ...

brown long-eared bat The brown long-eared bat or common long-eared bat (''Plecotus auritus'') is a small Eurasian insectivorous bat. It has distinctive ears, long and with a distinctive fold. It is extremely similar to the much rarer grey long-eared bat which was o ...

, and

whiskered bat The whiskered bat (''Myotis mystacinus'') is a small European bat with long fur. Although uncommon, ''M. mystacinus'' is often found around human habitation and around water; it is similar to Brandt's bat Brandt's bat or Brandt's myotis (''M ...

Notes

References

* * (Fact sheet and bathymetric map) * {{DEFAULTSORT:Orlangen Geography of Stockholm Lakes of Stockholm County

Catchment area

Environmental impact

Flora and fauna

See also

Notes

References