Overview

Brief Summary

In 2012, Aythya innotata was included among the world's 100 most threatened species in a report by the IUCN Species Survival Commission and the Zoological Society of London.

(Baillie & Butcher 2012; Harvey 2012)

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Distribution

Range Description

This species is endemic to Madagascar (although sub-fossil remains of an Aythya duck on Reunion are attributed to A. innotata), where it was found historically in the Lake Alaotra basin in the northern central plateau. It was considered relatively common at Lake Alaotra in the 1930s, but declined dramatically through the 1940s and 1950s (Young and Kear 2006, Rene de Roland et al. 2007). Until the 1990s, the last certain record was at Lake Alaotra in 1960, with one unconfirmed sighting near Antananarivo in 1970 and several other possible records. Then a single male was captured alive in August 1991. Intensive searches (including major publicity campaigns) at Alaotra during 1989-1990 and 1993-1994 failed to discover more birds. However, in 2006 the species was rediscovered when nine adults and four juveniles were observed at a volcanic lake situated 330 km north of Lake Alaotra (S.T. Seing in litt. 2006). Reports from local people that the lake was not suitable for rice cultivation round the edge, it contained no fish and that the water was cold suggest that the species may have persisted at this new location because human disturbance has been minimal (S.T. Seing in litt. 2006). Follow-up surveys in 2006 located c.20 mature individuals with up to nine ducklings observed at the same site (G. Young in litt. 2007). Five birds were seen at a second lake c.3-4 km from the site but these may be part of the 20 individuals counted previously. A total of 25 mature individuals were counted in 2008, with six pairs nesting in the 2007/08 season (L.-A. Rene de Roland in litt. 2008). However, no chicks fledged in 2008 or 2009 (P. Cranswick in litt. 2009, H. G. Young in litt. 2012), and only 19 adults were recorded in July 2009 (Jarrett 2010), including six females (Cranswick 2010). In 2011 there was again no successful breeding, and the lake was apparently in poor condition with little available food other than caddis fly larvae (Cranswick 2012), however a total of 29 mature individuals were counted (L.-A. Rene de Roland in litt. 2012). In 2012 a total of 21 individuals were counted (nine females and 13 males) and 20 breeding attempts were recorded (Bamford et al. 2015).

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Range

Lake Alaotra (Madagascar). On verge of extinction.
  • Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/

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Historic Range:
Madagascar

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Ecology

Habitat

Madagascar Subhumid Forests Habitat

The Lac Alaotra bamboo lemur (Hapalemur griseus aloatrensis) is strictly endemic to the Madagascar subhumid forests ecoregion. This ecoregion, coveris most of the Central Highlands of Madagascar, and boasts a considerable number of endemic species, found chiefly in the relict forest patches and also in some wetland areas. The rainfall here is approximately 1500 mm per year, although it may amount to as much as 2000 mm in the Sambirano area in the northwest and as little as 600 mm in the southwest.

The underlying geology of the ecoregion is mainly ancient Precambrian basement rocks that have been deformed and uplifted over millions of years. There are a few areas of more recent lava flows, and some alluvial deposits associated with wetlands. Vast grasslands now cover much of the central highlands at elevations ranging from 1000 to 1500 metres. The majority of this upland area was formerly forested, and native peoples have affected the fauna and flora through massive deforestation.

Many mammalian taxa are endemic to this ecoregion, including a number of lemurs and numerous shrews, tenrecs and rodents. A far larger number of species are near endemic, with the majority of these shared with the lowland forests to the east. At least 45 species of mammals are found only in the subhumid forest ecoregion and the lowland forest ecoregion of Madagascar and these include, for example, two species of bamboo lemurs (Hapalemur aureus and H. simus).

Of the endemic and near-endemic mammal species in the ecoregion, 12 species listed are on the IUCN Red List; nine species are considered vulnerable; two are endangered and one (the Alaotran gentle lemur) is critical. In the Analavelona forest a species of small mammal was recently discovered, Microgale nasoloi, that is only known from this site and the nearby Zombitse-Vohibasia Forest, the latter being classified in the Madagascar succulent woodlands ecoregion. In addition to the large number of mammalian endemics, there are many special status mammals in the ecoregion, including the Vulnerable Aquatic tenrec (Limnogale mergulus); the Near Threatened Aye aye (Daubentonia madagascariensis);

Two endemic bird species are found in the wetlands of this ecoregion, and others are confined to the subhumid forests or shared with other Madagascar ecoregions. In the wetlands, both the Alaotra little grebe (Tachybaptus rufolavatus) and the Madagascar pochard (Aythya innotata), are considered critically endangered and may be extinct. In the forests the endemic species include, for example, a new genus and species only named a few years ago called the cryptic warbler (Cryptosylvicola randrianasoloi), the yellow-browed oxylabes (Crossleyia xanthophrys), and the brown emutail (Dromaeocercus brunneus). Several other species of birds found here are limited to marshland habitats on Madagascar, including the slender-billed flufftail (Sarothrura watersi), Madagascar snipe (Gallinago macrodactyla), and Madagascar rail (Rallus madagascariensis). Further, Appert’s greenbul (Xanthomixis apperti), an endemic species with a very limited geographical distribution, is abundant on the upper reaches of the Analavelona Massif. More than 20 other bird species that occur in the subhumid forests of this ecoregion are shared only with the eastern lowland forests ecoregion.

The Madagascar subhumid forests hold more than twenty strictly endemic amphibians. Several groups of amphibians include more than one endemic species, such as the microhylids Rhombophryne testudo, Scaphiophryne goettliebi, the mantellids Vulnerable Elegant Madagascar frog (Spinomantis elegans); Mantella crocea, M. cowani, M. eiselti, Mantidactylus domerguei, and the Near Threatened Decary's Madagascar frog (Gephiyromantis decaryi); and the rhacophorids Boophis laurenti and B. microtympanum. Other notable amphibian endemics include:the Benavony stump-toed frog (Stumpffia gimmeli)/

There are a number of special status amphibians in the ecoregion including the Near Threatened Ambohimitombo bright-eyed frog (Boophis majori); the Vulnerable Andoany stump-toed frog (Stumpffia pygmaea); the Endangered Andringitra Madagascar Frog (Mantidactylus madecassus); and the Near Threatened Betsileo Bright-eyed Frog (Boophis rhodoscelis).

There are at least 25 strictly endemic reptiles in this ecoregion. These numbers include historically described species as well as newly identified taxa. Numerous speciess of chameleon and dwarf chameleon only occur in this ecoregion, including Calumma oshaughnessyi ambreensis, C. tsaratananensis, Furcifer petteri, Brookesia ambreesis, B. antakarana, B. lineata, and B. lolontany in the northern and northwestern portion; and C. fallax, F. campani, and F. minor in the central and southern portions. Otpher lizard species endemic to the ecoregion include the skinks Mabuya grnadidieri, M. madagascariensis, M. nancycoutouae, Amphiglossus meva, and Androngo crenni; the geckos Lygodactylus blanciL. decaryi and Phelsuma klemmeri, and the Plated lizard Zonosaurus ornatus. There are also a few endemic species of snakes including Pseudoxyrhopus ankafinensis, Liopholidophis grandidieri, and L. sexlineatus.


  • Du Puy, D.J. and Moat, J. 1996. A refined classification of the primary vegetation of Madagascar based on the underlying geology: using GIS to map its distribution and to assess its conservation status. In W.R. Lourenço (editor). Biogéographie de Madagascar, pp. 205-218, + 3 maps. Editions de l’ORSTOM, Paris. ISBN: 2709913240
  • World Wildlife Fund and C.MIchael Hogan/. 2015. Madagascar subhumid forests. Encyclopedia of Earth. National Council for Science and Environment. Washington DC
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Habitat and Ecology

Habitat and Ecology
Behaviour This species is generally sedentary and usually occurs singly, or occasionally in pairs (Langrand 1990). It is not known to flock or to associate with any other species (Kear 2005). Nesting has been observed during the months of July to February (Bamford et al. 2015). Some pairs may make multiple nesting attempts (Bamford et al. 2015).Habitat The species was historically only known from shallow freshwater lakes and marshes that combine open water with nearby areas of dense vegetation (Langrand 1990; Morris and Hawkins 1998; G. Young in litt. 2003). It probably prefers marshy areas and shallow water (G. Young in litt. 2003). However, the site of its rediscovery is a volcanic lake with very little emergent vegetation (G. Young in litt. 2007). What vegetation does grow at the lake edge may provide suitable nesting habitat. The requirement for shallow water may prevent it from using other volcanic lakes similar to the site of its rediscovery (G. Young in litt. 2007).The nest is sited amongst lake-edge vegetation (Cyperaceae) and placed 20-40 cm above water (Bamford et al. 2015). The clutch size is 6-10 eggs (L.-A. Rne de Roland and G. Young in litt. 2012). Diet It is believed to feed almost entirely on invertebrates with a minimal proportion of plant matter (Bamford et al. 2015).


Systems
  • Freshwater
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Source: IUCN

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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
CR
Critically Endangered

Red List Criteria
D

Version
3.1

Year Assessed
2015

Assessor/s
BirdLife International

Reviewer/s
Symes, A.

Contributor/s
Hawkins, F., Rabenandrasana, M., Rn De Roland, L., Seing, S., Watson, R. & Young, G.

Justification
This species was rediscovered in 2006 following the last sighting in 1991. It is currently known from a single location where 29 mature individuals were seen in 2011 and 21 in 2012. While it may also persist at other sites, the population is likely to be tiny and therefore it is classified as Critically Endangered.


History
  • 2013
    Critically Endangered (CR)
  • 2012
    Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Critically Endangered (CR)
  • Threatened (T)