Orlången is a

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

in central

Huddinge Municipality Huddinge Municipality () 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, the second most pop ...

, just south of

Stockholm Stockholm (; ) is the Capital city, capital and List of urban areas in Sweden by population, most populous city of Sweden, as well as the List of urban areas in the Nordic countries, largest urban area in the Nordic countries. Approximately ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

. Orlången, one of the lakes in the Tyresån Lake System, forms part of the

Orlången Nature Reserve Orlången Nature Reserve (''Orlångens naturreservat'') is a nature reserve surrounding Lake Orlången in central Huddinge Municipality, south of Stockholm, Sweden. Description The reserve, founded in 1998, encompasses a total area of 15 square ...

.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Though the mud-filled valleys surrounding Orlången originally made it moderately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 a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

, 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; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

, 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 * Re ...

club-rush ''Schoenoplectus'' (club-rush ld World species bulrush or tule ew World species is a genus of plants in the Cyperaceae, sedge family with a cosmopolitan distribution. Note that the name bulrush is also applied to species in the unrelated ...

, 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 plan ...

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 a ...

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", ...

yellow loosestrife Yellow loosestrife is a common name for several plants in the genus ''Lysimachia'' and may refer to: * ''Lysimachia'' × ''commixta'', native to eastern North America *'' Lysimachia punctata'' *''Lysimachia vulgaris ''Lysimachia vulgaris'', th ...

, bittersweet, yellow water-lily, white water-lily, broad-leaved pondweed, red pondweed, whorled water-milfoil, amphibious bistort, water-soldier, 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 fr ...

greater bladderwort ''Utricularia vulgaris'' (greater bladderwort or common bladderwort) is an aquatic species of bladderwort found in Asia and Europe. The plant is free-floating and does not put down roots. Stems can attain lengths of over one metre in a single g ...

, and greater duckweed. Along the shores of the lake are hybrid crack willow,

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

, 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 *''Sal ...

aspen Aspen is a common name for certain tree species in the Populus sect. Populus, of the ''Populus'' (poplar) genus. Species These species are called aspens: * ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') * ''Populus da ...

, 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 Pr ...

marsh fern ''Thelypteris palustris'', the marsh fern, or eastern marsh fern, is a species of fern native to eastern North America and across Eurasia. It prefers to grow in swamps, bogs, wet fields or thickets, fresh tidal and nontidal marshes, or wooded str ...

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

, marsh woundwort,

gypsywort ''Lycopus europaeus'', common names gypsywort, gipsywort, bugleweed, European bugleweed and water horehound, is a perennial plant in the genus ''Lycopus'', native to Europe and Asia, and naturalized elsewhere. Another species, '' Lycopus america ...

, creeping spearwort,

marsh cinquefoil ''Comarum palustre'' ( syn. ''Potentilla palustris''), known by the common name marsh cinquefoil,Streeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ''Collins Flower Guide''. Harper Collins also purple marshlocks and swamp cinquefoi ...

marsh-marigold ''Caltha palustris'', known as marsh-marigold and kingcup, is a small to medium sized perennial herbaceous plant of the buttercup family, native to marshes, fens, ditches and wet woodland in temperate regions of the Northern Hemisphere. It flow ...

, bittersweet, skullcap,

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 to ...

, 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 dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...

in the north-eastern end of the lake documented a presence of red-eyed damselfly, northern damselfly, azure damselfly,

brown hawker The brown hawker (''Aeshna grandis'') is a species of large Palearctic dragonfly belonging to the family Aeshnidae, the hawkers. This species is found in Europe and temperate Asia, except the far east of Asia. Taxonomy The brown hawker was first ...

, club-tailed dragonfly, downy emerald, 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 or The 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 * Cal ...

rudd ''Scardinius'' is a genus of freshwater ray-finned fishes belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related species. The fishes in this genus are commonly called rudds. Locally, the name "rudd" without ...

tench The tench or doctor fish (''Tinca tinca'') is a freshwater, fresh- and brackish water, brackish-water fish of the order Cypriniformes found throughout Eurasia from Western Europe including Great Britain, Britain and Ireland east into Asia as far ...

bleak Bleak may refer to: Fish * Species of the genus ''Alburnus'' * Some species of the genus ''Acanthobrama'' * ''Alburnoides bipunctatus'', also known as the schneider * ''Alburnoides oblongus'', Tashkent riffle bleak * ''Aphyocypris chinensis'', Chi ...

silver bream Silver bream is the common name of several species of fish: * ''Blicca bjoerkna'' (white bream), freshwater species of cyprinids from Europe and Western Asia * ''Acanthopagrus australis'' (surf bream), marine and freshwater species of sea bream from ...

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

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''), also known as bubbot, mariah, loche, cusk, freshwater cod, freshwater ling, freshwater cusk, the lawyer, coney-fish, lingcod, or eelpout, is a species of coldwater ray-finned fish native to the subarctic regions of ...

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

zander The zander (''Sander lucioperca''), sander or pikeperch, is a species of ray-finned fish from the Family (biology), family Percidae, which also includes perch, Gymnocephalus, ruffe and Darter (fish), darter. It is found in freshwater and brackis ...

, and

ruffe The ruffe (''Gymnocephalus cernua''), also known as the Eurasian 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 as an invasive species ...

Signal crayfish The signal crayfish (''Pacifastacus leniusculus'') is a species of crayfish indigenous to North America. Introduced to Europe in the 1960s to supplement the North European ''Astacus astacus'' fisheries, which were being damaged by crayfish plague ...

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. The bird is characterised by its distinctive appearance, featuring striking black, orange-brown, and white plumage, and elaborate courtship displa ...

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 Eurasia, and (as a rare winter visitor) the far north of Africa. It is an introduced species in North America, home to ...

Canada goose The Canada goose (''Branta canadensis''), sometimes called Canadian goose, is a large species of 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 A ...

mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa. It 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 usual ...

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

osprey The osprey (; ''Pandion haliaetus''), historically known as 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 a wingspan of . It ...

marsh harrier The marsh harriers are bird of prey, birds of prey of the harrier (bird), harrier subfamily. They are medium-sized Bird of prey, raptors and the largest and broadest-winged harriers. Most of them are associated with marshland and dense reedbeds. ...

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

sandpiper Scolopacidae is a large family of shorebirds, or waders, which mainly includes many species known as sandpipers, but also others such as woodcocks, curlews and snipes. Most of these species eat small invertebrates picked out of the mud or so ...

tern Terns are seabirds in the family Laridae, subfamily Sterninae, that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated in eleven genera in a subgroup of the family Laridae, which also ...

gull Gulls, or colloquially seagulls, are seabirds of the subfamily Larinae. They are most closely related to terns and skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gulls were placed ...

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 famil ...

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

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 incorpor ...

, 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 Leaf, 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 flora (plants), plants and fauna (animals), animals. ''Biotope'' is almost synonymous with the term habitat (ecology), "habitat", which ...

for

bat Bats are flying mammals of the order Chiroptera (). 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 birds, flying with their very long spread-out ...

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 France to Hokkaidō and south to Kazakhstan. Description The northern bat is dark brown or black with some gold touched at the tip ...

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 occurs across Eurasia, from Ireland in the west to Hokkaido in the east, and is believed to be increasing its numbers in many areas of it ...

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 Biological specificity is the tendenc ...

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 ...

, 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 (''Myotis brandtii''), from which it wa ...

. Orlången vinter 2012a.jpg, Orlången in the winter. Orlången Stensätra 2011.jpg, Orlången. Sundby gård värdshuset 2012.jpg, Sundby estate, 2012.

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