The Sango Bay area, north of the Uganda–Tanzania border, adjoins the Lake Nabugabo area to the north. The main road between Masaka and Mutukula at the Tanzanian border marks its western limit; its eastern limit is the Lake Victoria shoreline. There are wetlands, grasslands and forests. In total, the forests within this site cover 15,000 ha. There are five Forest Reserves: Kaiso, Tero East and West, Namalala and Malabigambo. All are of a rather homogeneous nature, broadly classified as swamp-forest, formerly important for its Podocarpus timber species, most of which have been logged out over the past 100 years.
The canopy is generally lower than that of medium-altitude mixed evergreen forest, although many of the component species are the same. The area is considered of biogeographic interest because it lies in the transition between the East and West African vegetation zones. There is evidence that the area was a Pleistocene refugium. The Malabigambo Forest is contiguous with Minziro Forest of neighbouring Tanzania. The site also contains a mosaic of wetland types, including permanent and seasonal swamp-forests, papyrus Cyperus papyrus swamps, herbaceous swamps interspersed with palms, and seasonally flooded grasslands. The Sango Bay wetlands are extensive, stretching along the shores of Lake Victoria from Kyabasimba in the south to Malembo in the north. In areas such as Kyabasimba, the shoreline is varied, with sandy shores, rocky shores, forested shores and a fishing village. The shoreline of the bay itself is fringed by papyrus, merging into the extensive flood-plains of the Bukora river delta. The bay is relatively unsheltered and experiences serious wave action. As a result, there is little fringing water-hyacinth Eichhornia, unlike bays in the Entebbe area. At Sango Bay itself, there is a small fish-landing site and an old disused pier, whose structures are important roosts for birds. At the mouth of the River Kagera, the shore is relatively exposed, with mainly sandy shores merging into papyrus swamp. The deposition of silt carried by the Kagera has led to the creation of a wide shallow belt with a sandbar at the river mouth.
Sango Bay wetland system
This is a mass wetland system that consists of Kagera, Sango Bay itself and the Musambwa Island. It is one of the most important areas in terms of tourism potential, flora and fauna biodiversity as well as supporting the surrounding communities.
The Forest Reserves consisting of Kigona, Kaiso, Tero (East and West), Namalala and Malabigambo are part of the Sango Bay area and are rather homogenous in nature and the biggest section can be broadly classified as swamp forest. Malabigambo Forest and Kaiso wetlands are contiguous with the Minziro Forest wetlands of neighbouring Tanzania and important as an international cross-border management site. The site contains a mosaic of wetland types including permanent and seasonal swamp forests, papyrus swamps, herbaceous swamps interspersed with palms and seasonally flooded grasslands. Malabigambo Forest is contiguous with Kagera wetland and floodplain mainly composed of a mat of papyrus swamp sectioned by the meandering Kagera River. Kagera swamp runs to the Tanzanian border.
It is also of national and international interest. It contains one of the World’s Stone Age Sites, internationally known as the Sangoan, which dates to about 200,000 years ago. The system is a source of fish to the people of the area, source of medicinal plants, raw materials for building and making crafts including luxurious sofa chairs and mattresses. The plains are also used for grazing and tourism has been developed on Musambwa Island. Sango Bay wetland system is part of the area in Uganda, which supports more than 75% of the global population of the Blue swallow.
In addition, the system supports huge congregations of waterbirds, unique plant communities including endemic tree species, breeding ground for several fish species, contains globally endangered mammals and restricted range primate species and is considered to be a Pleistocene refugium.
The rocky area of Musambwa, one of the biggest breeding sites for water birds and large extents of seasonally flooded areas that contain a large population of wintering Blue Swallows in Uganda.
The major area of interest is the Kagera system and associated swamp forest in the Malabigambo Forest Reserve. The forest reserve is contiguous with the permanent swamp and completely floods in the wet season.
The Shoebill Balaeniceps rex (Vulnerable) also occurs in the seasonally flooded swamps in Sango Bay area and is thought to occur in large numbers in the Kagera extensive wetlands.
Sango Bay-Musambwa-Kagera area is unique in many ways because of its biogeographical location. It is found in the transition between the East and West African vegetation zones and this biogeographical ecotone makes it biodiversity rich. A total of 331 species of vascular plants belonging to 88 families were recorded. Of these 122 were herbs, epiphytes or hemi epiphytes belonging to 35 families; 68 lianas belonging to 38 families and 141 trees and shrubs belonging to 42 families.
Unique fauna have been recorded in the area. These include 65 species of mammals and 417 species of birds including huge congregations of migratory species such as the White-winged Black Tern Chlidonias leucopterus and large numbers of Squacco Herons (Ardeola ralloides). Musambwa islands in Sango Bay contain the biggest known breeding colony of Grey-headed Gulls (Larus cirrocephalus) as well as the only breeding area known for the Little Egrets (Egretta garzetta) and Long-tailed Cormorants (Phalacrocorax africanus) in Uganda. The Papyrus Gonolek Laniarius mufumbiri is a papyrus endemic which is common and vocal in the Sango Bay-Kagera swamps. Great White Pelicans (Pelecanus onocrotalus) roost at the mouth of the River Kagera in several hundreds and small numbers of Pink-backed Pelicans (Pelecanus rufescens).
In addition, this wetland complex contains over 50 guinea-congo biome bird species of the 142 bird species found in the whole biome that stretches from Liberia to Kakamega Forest in Eastern Kenya: of these over 30 are restricted to the forest interior. It contains 8 out of the 12 bird species of the lake Victoria basin restricted Biome and one record of an afrotropical Highlands biome bird species, Chubbs Cisticola (Cisticola chubbi). The occurrence of these species at such low altitude is indicative of a unique and complex biological diversity.
Thirty one (31) species of fish including Clarias spp, Protopterus aethiopicus and Labeo victorianus have been recorded. The Sango Bay ecosystem of wetlands and forests contains 14% of the fish species of Uganda. It has endemic fish such as Oreochromis esculentus and O. variabilis. The invertebrate communities observed include a large variety of butterflies and dragonflies for which 259 and 67 species have been recorded respectively. The System contains an endemic dragonfly Macromia bispina and endemic butterflies Tametheira orientalis, Elymnias bammakoo and Charaxes imperialis ugandicus.