Ruskohypikäs

Die Dunkle Hüpfmaus (Notomys fuscus) ist ein Nagetier aus der Gattung der Australischen Hüpfmäuse (Notomys).

Beschreibung

Die Kopf-Rumpflänge beträgt 80 bis 115 mm. Die Schwanzlänge erreicht zwischen 120 und 155 mm. Die Hinterfußlänge beträgt 35 bis 40 mm und die Ohrenlänge 24 bis 28 mm. Das Gewicht beträgt zwischen 20 und 50 g. Der hellorange bis graue Rücken kontrastiert scharf mit der weißen Unterseite. Beide Geschlechter haben einen Kehlsack. Die Weibchen besitzen vier Bauchzitzen.

Verbreitung

Ihr Verbreitungsgebiet erstreckt sich über das südwestliche Queensland (Pelican Waterhole), das nordöstliche South Australia (südliche Strzeleki Desert und Cobblers Desert sowie Carraweena, Montecollina Bore und die Quinyambie Station) bis zum westlichen New South Wales.

Lebensweise

Diese Art ist ein Bewohner der Sanddünen. Sie gräbt einen Bau rund einem Meter unter der Oberfläche, der bis zu fünf Meter lang sein kann. Bis zu fünf Tiere können dann in zwei benachbarten Erdhöhlen leben. Sie geht bei Nacht auf Nahrungssuche und ernährt sich von Sämereien, Blättern und gelegentlich Insekten. Über das Brutverhalten in der Wildnis ist nur wenig bekannt, jedoch weiß man von Tieren, die in menschlicher Obhut gezüchtet haben, dass die Tragzeit 38 bis 41 Tage betrug und ein bis fünf Junge großgezogen wurden. Die Weibchen werden nach 70 Tagen geschlechtsreif.

Gefährdung

Die Dunkle Hüpfmaus ist eine ziemlich seltene Art. Von der IUCN wird sie als vulnerable (gefährdet) und im Nature Conservation Act (Naturschutzgesetz von Queensland) wird sie als endangered (stark gefährdet) gelistet. In weiten Teilen Südaustraliens und im südwestlichen Nordterritorium ist sie ausgestorben. Die Gründe für den Rückgang sind bis heute nicht ganz erforscht. Hauptfaktoren sind aber vermutlich eingeführte Füchse, verwilderte Hauskatzen sowie die Veränderung ihres Lebensraumes durch grasende Viehherden und Kaninchen.

Literatur

• Peter Menkhorst: A Field Guide to the Mammals of Australia. Illustrated by Frank Knight. Oxford University Press, South Melbourne u. a. 2001, ISBN 0-19-550870-X.
• Ronald Strahan (Hrsg.): The Mammals of Australia. The National Photographic Index of Australian Wildlife. Revised edition. New Holland, Sydney 1998, ISBN 1-87633-401-0.

Weblinks

• Queensland Parks and Wildlife Serve - Dusky Hopping Mouse (Memento vom 27. April 2009 im Internet Archive)
• Notomys fuscus in der Roten Liste gefährdeter Arten der IUCN 2006. Eingestellt von: J. Baille, 1996. Abgerufen am 1. November 2006.

The dusky hopping mouse (Notomys fuscus), is a small rodent endemic to Australia, inhabiting desert regions characterised by sand dunes. Populations have experienced significant declines since the arrival of Europeans, and continue to be subject to threatening processes. It is currently listed as a threatened species.^[2]

Taxonomy

Adult dusky hopping mouse (Notomys fuscus). Photo: Katherine Moseby.

The dusky hopping mouse, or Wilkinti,^[2][3] is a mammal in the order Rodentia, and suborder Sciurognathi. The species is in the family Muridae and the subfamily Murinae (includes all Australian native rats and mice). The dusky hopping mouse belongs to the genus Notomys, a group of desert-dwelling rodents.^[4]

The species was originally described as Ascopharynx fuscus (Wood Jones 1925) from a specimen collected in South Australia. Subsequent collections were described as Notomys fuscus eyreius in 1960.^[5] Hopping mice collected in Queensland between 1957 and 1959 were described as a new species, Notomys filmeri, however, later taxonomic investigation revealed these were Notomys fuscus.^[6]

Description

Specimen of dusky hopping mouse (Notomys fuscus), showing throat pouch. Image: Queensland Museum.

The dusky hopping mouse has pale orange-brown upper parts, occasionally with grey tinged streaks. The under parts are grey-white.^[7] It grows to 80–115 mm long,^[7] with an average weight of 35 g.^[4][7] The tail is between 120 and 155 mm long,^[7] ending in a tuft of dark hairs.^[2][8] They have a well-developed throat pouch, with an opening surrounded by a fleshy margin with inward pointing, coarse white hairs.^[7][9] Its ears are large and furless for dissipating heat, and they have prominent dark eyes,^[2][10] and strong incisor teeth.^[8][10] It has short front legs, and long, elongated hind feet.^[2][8] with only three pads on the sole.^[7] Male reproductive anatomy is distinctive.^[4] The glans is small and tapered towards the tip. The surface has large dorsally projecting spines, with slightly curved tips.^[11] The testes are extremely small compared to other native rodents.^[12][13] Females have two pairs of inguinal teats.^[7][8]

Distribution

Sub-adult dusky hopping mouse (Notomys fuscus). Photo: Katherine Moseby.

The species historically inhabited large areas of central Australia, south-west Queensland, and far west South Australia,^[14] and Western Australia.^[15] Sub-fossil specimens were found in far-south South Australia, near the Flinders Ranges.^[14] Populations were recorded in the Northern Territory, however have not been observed since 1939.^[16][17] It is highly likely to have occurred in western New South Wales.^[18] Distribution has shown a marked decline of more than 90% since the arrival of Europeans,^[14] with populations now patchy and highly fragmented.^[2][14] It is currently thought to be restricted to the Cobblers Sandhills and Strzelecki Desert in north-east South Australia,^[14][15] south-west Queensland and far north-west New South Wales.^[7][19] The species was presumed to be extinct in New South Wales, before being re-discovered in Sturt National Park in 2003.^[18][20] Since then, a number of sightings have been recorded near Broken Hill, New South Wales.^[20][21]

Ecology

Habitat

The Strzelecki Desert, contains habitats preferred by the dusky hopping mouse (Notomys fuscus). Photo: Mike Letnic.

The preferred habitat of the dusky hopping mouse is the crests and slopes of stabilised desert sand dunes and ridges,^[15][20] with sand required for digging burrows.^[22] Dense populations tend to occur only within the vicinity of major drainage systems.^[14] It does not appear to favour a particular vegetation type, occurring in dunes well-vegetated by canegrass (Zygochloa paradoxa), as well as degraded ecosystems dominated by ephemeral herbaceous species.^[14] It has also been associated with perennial shrub species such as nitre bush (Nitraria billardierei) and Acacia species.^[20]

Behaviour

The dusky hopping mouse is a social species,^[7] living in colonies of up to five individuals.^[20][22][2] They live in burrows consisting of vertical shafts with a series of entrances approximately 3 cm in diameter,^[7][2] leading to a network of horizontal tunnels and chambers^[3][4] extending up to 2m deep.^[22] Notomys species dig their burrows from below, resulting in an absence of loose sand surrounding the entrance holes.^[10] This species prefers to forage at night in sheltered microhabitats, rather than open areas, to avoid the risk of predation.^[23] It is an opportunistic,^[14] omnivorous feeder, however is considered a granivore (74% of the diet).^[24] Green plant material, insects,^[24] and fruits are also eaten.^[14] It does not need to drink water.^[2][20] The neck throat pouch is a glandular area, used for marking territories. Females may scent-mark their young, ensuring they acquire a smell that grants them acceptance within the colony.^[9]

Dusky hopping mouse (Notomys fuscus) tracks in the sand. Photo: Mike Letnic.

Life cycle and reproduction

In the wild, lifespan has been recorded as being up to 13 months of age.^[22] In captivity, males and females reach reproductive maturity at 70 days of age.^[25] This species is likely monogamous, and females may display selectivity in choosing which males will sire offspring.^[10][13] Breeding is non-seasonal, occurring year-round, in both wet and dry conditions.^[14][25] Females are observed to be polyoestrous, with a gestation period of 32 to 38 days, and a litter size of one to five offspring. An average of 42 days occurs between litters, and the maximum reproductive life for females is approximately 24 months, and males 36 months.^[25] Subpopulations may persist at low but stable numbers, however others exhibit “boom-and-bust” variation, with numbers increasing and decreasing rapidly in response to rainfall and resource availability.^{[21][22][26][27]}

Dispersal and movement

When travelling slowly, hopping mice move on all fours, however they hop on the hind feet when travelling at speed.^[4][8] Individuals can disperse over large distances to colonise isolated habitats, crossing areas of hard unsuitable substrate.^[22] Foraging distances are up to 400m per night, extending up to 1.5 km over three nights.^[22][26] Individuals inhabiting degraded habitats with limited vegetation and food resources show lower mobility, whereas those inhabiting highly diverse habitats with a wide variety of resources have wider ranging movement patterns.^[26]

Threats

Predation

Feral cats (Felis catus) target small mammals as prey, such as native rodents. Photo: Megan Moppett.

Introduced predators such as the red fox (Vulpes vulpes)^[28] and feral cat (Felis catus) have detrimental impacts on dusky hopping mouse populations.^[23][29] Where cat and fox abundance is high, dusky hopping mouse populations decline.^[28][29][30] Cats target smaller prey such as rodents, which can make up a large proportion of their diet.^[31] Native species, such as the barn owl (Tyto alba), frequently consume this species,^[23][32] as does the dingo.^[23][33] Dingoes may de-populate localised populations of hopping mice within months,^[34] particularly under drought conditions.^[33] Crest-tailed mulgara (Dasycercus cristicauda) have also been recorded eating this species.^[35]

Habitat degradation

Livestock, kangaroos and rabbits overgraze vegetation required for shelter and food sources,^[20] leading to scalding, wind and sheet erosion and a shift from perennial, to less productive ephemeral plant species.^[14][26] Livestock also damage habitats by trampling.^[31][36] Reduced food availability limits hopping mice abundance, and the availability of suitable habitat limits their distribution.^[14][26] However, higher annual rainfall and more productive ecosystems may buffer the effects of livestock, by providing more dependable and abundant resources, allowing mice to proliferate.^[14][33]

Sub-adult Dusky Hopping Mouse (Notomys fuscus). Photo: Katherine Moseby.

Competition

Competition for food and habitat occurs with the house mouse (Mus musculus),^[22] which increase in abundance more rapidly under favourable conditions, depleting resources and outcompeting the native mice.^[14] The rabbit (Oryctolagus cuniculus) also competes with dusky hopping mice for food. Declines in rabbit abundance, and increased resources, following the release of the Rabbit Haemorrhagic Disease Virus (RHDV) in Australia in 1995, saw the dusky hopping mouse increased their extent of occurrence by 241 to 365% over 14 years.^[37]

Climate Change

This species experiences natural population declines during dry periods, when food resources are limited, and increase strongly following rainfall events.^[26][33] Decreases in rainfall, less frequent rainfall events and more frequent droughts under climate change may cause declines or extinctions.^[19][22] Predation of hopping mice by dingoes intensifies under drought conditions, which may significantly impact populations.^[33]

Conservation status

Dusky hopping mouse (Notomys fuscus) in the Strzelecki Desert. Photo: Sue Rodwell.

The total remaining population is estimated to be between 2,500 and 10,000 individuals.^[2][14]

• International Union for the Conservation of Nature (IUCN) Red List: Vulnerable^[22]
• Australia: Vulnerable (Environment Protection and Biodiversity Conservation Act 1999)^[2][19]
• New South Wales: Endangered (Biodiversity Conservation Act 2016 No 63)^[38]
• South Australia: Vulnerable (National Parks and Wildlife Act 1972)^[39]
• Queensland: Endangered (Nature Conservation Act 1992)^[40][41]
• Northern Territory: Endangered (Territory Parks and Wildlife Conservation Act 2000)^[17][42]

References

Wikimedia Commons has media related to Notomys fuscus.

Notomys fuscus Notomys generoko animalia da. Karraskarien barruko Murinae azpifamilia eta Muridae familian sailkatuta dago.

Erreferentziak

• Notomys fuscusri buruzko informazioa Mammals of The World datubasean

Ikus, gainera

• Notomys
• Muridae

Il topo saltatore scuro (Notomys fuscus Jones, 1925) è un roditore della famiglia dei Muridi diffuso in Australia.^[1][2]

Descrizione

Roditore di piccole dimensioni, con la lunghezza della testa e del corpo tra 80 e 115 mm, la lunghezza della coda tra 120 e 155 mm, la lunghezza del piede tra 34 e 40 mm, la lunghezza delle orecchie tra 24 e 28 mm e un peso fino a 50 g.^[3]
Le parti superiori sono arancioni, talvolta miste al grigiastro, particolarmente sulla testa. Le parti inferiori sono bianche. Sono presenti solo tre cuscinetti sulla pianta dei piedi. La coda è più lunga della testa e del corpo. Entrambi i sessi hanno delle sacche golari ben sviluppate, circondate da una parte carnosa ricoperta di ruvidi peli biancastri. Il cariotipo è 2n=48 FN=52.

Biologia

Comportamento

È una specie terricola, notturna e gregaria. Si rifugia in profondi sistemi di tane e cunicoli, costruiti nelle dune sabbiose.

Alimentazione

Si nutre di semi, germogli e insetti.

Riproduzione

Le femmine danno alla luce 1-5 piccoli alla volta dopo una gestazione di 38-41 giorni. Le nascite avvengono subito dopo le stagioni piovose, sebbene in cattività si riproducano durante tutto l'anno.

Distribuzione e habitat

Questa specie è diffusa nella parte nord-orientale dell'Australia Meridionale, nella parte sud-occidentale del Queensland e in una piccola zona del Nuovo Galles del Sud nord-occidentale. In passato l'areale era più esteso e comprendeva gran parte dell'Australia Meridionale e della parte meridionale del Territorio del Nord.

Vive in pianure e creste sabbiose.

Tassonomia

Sono state riconosciute 3 sottospecie, di cui una estinta:

• N.f.fuscus †: Vissuta in epoca recente nella parte meridionale del Territorio del Nord;
• N.f.eyreius (Finlayson, 1960): parte nord-orientale dell'Australia Meridionale, Nuovo Galles del Sud nord-occidentale;
• N.f.filmeri (Mack, 1961): parte sud-occidentale del Queensland.

Conservazione

La IUCN Red List, considerato l'areale limitato e seriamente frammentato e il continuo declino nella qualità del suo habitat, classifica Notomys fuscus come specie vulnerabile (VU).^[1]

Note

Bibliografia

• Peter Menkhorst & Frank Knight, A Field Guide to the Mammals of Australia, Oxford University Press, USA, 2001, ISBN 978-0-19-550870-3.

검은껑충쥐(Notomys fuscus)는 쥐과에 속하는 설치류의 일종이다.^[2] 오스트레일리아 토착종으로 중부 지역 사막의 토착종이다. 인적이 드문 사막 지대의 생활할 수 있도록 특화되어 있다. 다른 모든 껑충쥐와 마찬가지로 강한 앞 이빨과 긴 꼬리, 짙은 눈, 큰 귀, 잘 발달한 엉덩이, 아주 길고 좁은 뒷발을 갖고 있다. 몸무게는 20~50g이다.(일반적인 집쥐는 10~25g이다.) 발바닥에 4개의 발바닥 살이 붙어 있다. 털 색은 다양하지만 연한 오렌지색을 띠며, 회색을 띠기도 하며 하체는 희다. 털은 짧고 섬세하며 부드럽다. 긴 털의 끝은 짙은 붓꼬리 형태를 띤다. 특정 시기가 아닌 조건에 맞는 때에 연중 번식을 한다. 암컷은 4개의 젖꼭지를 갖고 있으며, 태어나 약 70일 수에 성적으로 성숙해진다.

검은껑충쥐는 취약종으로 분류한다. 오래된 기록에는 한때 퀸즐랜드주 일부와 뉴사우스웨일스주, 멀리 [빅토리아 주]], 노던 준주, 사우스오스트레일리아주를 포함한 오스트레일리아 중부 지역에서 넓은 분포 지역을 차지했던 것으로 보이지만, 현재는 스첼레키 사막에서 소수의 제한된 지역과 사우스오스트레일리아 주와 퀸즐랜드 주 경계 지역 근처에서만 발견된다.^[3] 노던 준주에서도 일부가 살고 있는 것으로 추정되지만, 2000년과 2002년 탐사에서는 발견되지 않았다.

나머지 개체군은 연결된 모래 언덕과 다년생 식물이 있는 모래 서식지, 호수 또는 물길 가까운 지역에 집중적으로 분포한다.(오트레일리아 중부에서 "호수"는 일반적으로 건조하며, 영구적인 지표수는 아주 드물다.) 검은껑충쥐는 야행성 동물이고, 군집성 동물이다. 낮 동안에는 아주 깊은 굴 속에 숨어 지낸다. 굴 입구 직경은 약 3cm이고, 굴 깊이는 수직으로 약 1.5m 정도이다.

검은껑충쥐 개체수가 감소 추세를 보이는 이유가 아직 완전히 밝혀지지 않았지만, 특히 소와 토끼 등 도입종과의 먹이 경쟁과 포식자인 도입종 고양이와 여우 때문으로 추정된다.^[4]

각주