The site encompasses Lake Manyara National Park, the part of the lake which falls outside the park and the Marang Forest Reserve on the escarpment above the park. Lake Manyara is 40 km long by 13 km wide and is oriented almost north–south along the western margin of the Eastern Rift, some 85 km south of Lake Natron (TZ031). The escarpment rises 900 m above the level of the lake leaving a narrow western shore of Acacia–Commiphora woodland with sizeable stands of groundwater forest dominated by Trichilia roka with Croton macrostachyus and Cordia africana. The lake is generally saline (pH levels vary with rainfall) with areas of fresher water where perennial streams flow into the lake. The largest of these is the Simba river which drains from the Ngorongoro Highlands to the north-west and the Makayuni river which flows in from the east. There are extensive swamps in the north and smaller ones elsewhere associated with the minor rivers flowing off the escarpment. The level of the lake fluctuates considerably between seasons and between years and is occasionally reduced to a relatively small saline pool. On the escarpment, the Marang forest is composed of montane vegetation dominated by Olea capensis, Albizia gummifera, Podocarpus latifolius and Macaranga sp. The drier plateau forest contains Bersama abyssinica and Clausena anisata with Croton sp. and Olea africana as canopy dominants.
See Box and Tables 2 and 3 for key species. The groundwater forest to the north of the lake, and largely within the National Park, is a well-known breeding site for thousands of Pelecanus rufescens and Mycteria ibis along with much smaller numbers of Leptoptilos crumeniferus and Ardea cinerea. The lake holds huge numbers of Phoenicopterus minor with nearly 2 million birds recorded in 1991. However, only 78,320 birds were counted in 1994. Observations of Porzana porzana and Anthus cervinus suggest the muddy margins of the lake provide important feeding habitat for long-distant migrants. Histurgops ruficauda is locally common to the east of the lake, but uncommon within the park, especially during periods of high water when open grassland is inundated.Several other species of global conservation concern have been reported: Ardeola idae is infrequently recorded the northern swamps; Falco naumanni occurs on the plains east of the lake, with a flock of 400 recorded in 1961, and Circus macrourus are uncommon in the same area; a single Falco fasciinucha was recorded from the park in 1961.
Non-bird biodiversity: There is an important population of Loxodonta africana (EN) within the National Park and Marang Forest Reserve. There are a few prides of Panthera leo (VU) within the National Park.
Pressure/threats to key biodiversity
The north-western quarter of the lake, including some of the important swamp in the north and the groundwater forest, is well protected within the Lake Manyara National Park. The eastern and southern shores are unprotected and are utilized by Masai tribesmen and their stock. The land to the north-east lies within the Mto wa Mbu Game Controlled Area which regulates the hunting of wild animals along the shoreline, but offers no habitat protection. The entire lake and parts of the eastern shore should be given stronger protection. There is anecdotal evidence to suggest that the inflow of freshwater to the lake has declined as a result of increased irrigation, higher levels of tourism, increasing population demographics, especially in Mto wa Mbu, and general deforestation and land degradation, particularly on the plateau to the west of the park. There is also concern that deforestation is leading to increased siltation of the lake. Marang is an important catchment forest and is under considerable pressure from villagers in the Mbulu Highlands. The Forest Reserve is currently being incorporated into the National Park.
BirdLife International (2021) Important Bird Areas factsheet: Lake Manyara. Downloaded from
http://www.birdlife.org on 04/12/2021.