This EBA includes lakes, pools and marshes in eastern Madagascar, including those at sea-level (notably in the region of the Pangalanes Canal) and in the uplands. The boundary of the EBA has been difficult to define as these wetland areas are patchy and often small, being, in many cases, small areas of aquatic habitat within the East Malagasy wet forests (EBA 094), and therefore not always featuring on generalized vegetation maps. The extent of the EBA is thus similar to that of the eastern rain forests, although the EBA has been represented by a coastal strip and a handful of key inland localities, including the wetlands around Lake Alaotra (220 km², the largest lake in Madagascar) and those around Lake Itasy, which are (or have been) very important sites for restricted-range species.

Two species have very small distributions: Tachybaptus rufolavatus is known chiefly from Lake Alaotra, and Aythya innotata is also restricted largely to this same region although there are isolated data on its presence elsewhere, including at Lake Itasy. The remaining extant species are more widespread, with Anas melleri being also known from a few sightings in the West Malagasy wetlands (EBA 096) and Actophilornis albinucha largely occurring there, being extremely rare and possibly extinct in this EBA.

Another species of the West Malagasy wetlands, Madagascar Heron Ardea humbloti, has also been recorded in this EBA but has not been included as one of its restricted-range species because the records are presumed to be of wandering juveniles.

Lake Alaotra is a rice-producing centre of national importance; since 1923 it has been undergoing a transformation for agricultural purposes and its water has become heavily laden with sediments because of the intense erosion affecting neighbouring hills (Langrand 1990, Pidgeon 1996). It is also heavily polluted with insecticides (including DDT), and, as a result, there is very little aquatic vegetation. In addition, areas under rice cultivation quickly become unusable, resulting in new areas constantly being required and the continuing erosion of reedbed and shallow water (A. F. A. Hawkins in litt. 1995).

Three of the four species endemic to this EBA are considered highly threatened: there have been no reliable records in the last 10 years of Tachybaptus rufolavatus, which is in the irreversible process of disappearing through hybridization with Little Grebe T. ruficollis (a recent colonizer of Madagascar), hunting and trapping, the various impacts of introduced fish (which considerably limit the development of aquatic vegetation), probably poisoning through pesticides and loss of habitat; Aythya innotata has also become increasingly rare during the twentieth century, with one record at Lake Alaotra in 1960, a sighting near Antananarivo in 1970, and the capture of a single bird in 1991 which later died in captivity (Wilmé 1994); Sarothrura watersi is known only from a few well-separated areas in this EBA, including most recently from Ranomafana, now a national park; its distribution appears coincident with that of the much-pressurised East Malagasy wet forests (EBA 094), and habitat loss and degradation there will also affect this wetland species.

There is currently no protection specifically for wetlands in this EBA, although some sites (e.g. Vohiparara marsh in Ranomafana) fall incidently within protected areas. Conservation action in Madagascar has traditionally been oriented towards forests as they harbour the highest proportion of endemic species (Langrand and Goodman 1995). More surveys are therefore required to identify sites holding wetland species, especially those that are far from habitation and thus unlikely to be under immediate threat from conversion to ricefields (A. F. A. Hawkins in litt. 1996; see also Langrand and Wilmé 1993). To assess and prioritize suitable wetlands for protection, a monitoring procedure has been proposed using birds as indicators, e.g. Madagascar Grebe Tachybaptus pelzelnii, a widespread threatened species (classified as Vulnerable), and Anas melleri (Langrand and Goodman 1995; see also Pidgeon 1996).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: East Malagasy wetlands. Downloaded from https://datazone.birdlife.org/eba/factsheet/111 on 22/11/2024.