Mafia Island (6975)
Tanzania, Africa
Site overview
KBA status: confirmed
Year of last assessment: 2004
National site name: Mafia Island
Central coordinates: Latitude: -7.8333, Longitude: 39.7833
System: marine, terrestrial
Elevation (m): 0 to 25
Area of KBA (km2): 296.82233
Protected area coverage (%): 99.32
KBA classification: Global
Legacy site: Yes
Site details
Site description: The Mafia group of islands lie 25 km off mainland Tanzania, virtually opposite the Rufiji Delta (TZ032). They consist of the main island and a number of much smaller islands and islets. They are essentially all coral rock islands with some of the smaller ones nothing more than a sandbank at low tide. The coastal bush vegetation has been largely replaced by coconut plantations and small-scale agriculture. The vegetation was heavily degraded as long ago as the 1940s and only small patches of coastal forest remain.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs. KBA identified in the process of compiling the 2003 CEPF Ecosystem Profile of the Eastern Arc Mountains and Coastal Forests Hotspot (which was later [in 2005] split into two Hotspots, the East Afromontane and the Coastal Forests of Eastern Africa). Species taxonomy and threat category was based on IUCN Red List 2002.
Additional biodiversity: See Box for key species. The islands are known to hold at least 154 species. They are particularly important for Dromas ardeola with 500–1,000 birds recorded at Chole Bay in 1997 and 1998. The site also holds good numbers of Tringa cinerea, Pluvialis squatarola and Calidris ferruginea. Sterna bergii occurs and Sterna dougallii used to breed on the smaller islets and may still do so. The local breeding population of Ardea goliath on coastal islets is worthy of note. The race Cercotrichas quadrivirgata greenwayi is endemic to Zanzibar and the Mafia islands. Centropus superciliosus loandae are common on Mafia island and appear to breed alongside smaller numbers of the black-capped Centropus superciliosus burchelli. Non-bird biodiversity: The area has, until quite recently, been an important breeding ground for sea-turtles. However, the levels of poaching for meat and carapace have increased far beyond any sustainable offtake. A newly described toad, Stephopaedes howelli, has been found in the remnant coastal forest.
Habitats
Land use: agriculture | fisheries/aquaculture | nature conservation and research
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 100 |
Threats
Summary of threats to biodiversity at KBA: The Mafia Marine Park includes most of the south-western shoreline and a number of islets to the south and as far west as Boydu island. The establishment of the marine park has offered hope of long-term protection to a significant portion of the remaining important habitat. Other sites around Mafia may well hold important numbers of waterbirds, but habitat degradation continues to some extent, with dynamite fishing and coral extraction among the major problems. There is little remaining coastal forest on Mafia and there is little hope for these remnants without formal protection. There is no recent data available on the extent of harvesting of seabird colonies for eggs. A proposed prawn farm in the Rufiji Delta would degrade the natural fisheries in the vicinity of the delta and would probably affect fish populations around Mafia.
Additional information
References: Bregnballe et al. (1990), Bryceson (1978, 1981), Horrill and Ngoile (1991), Horrill et al. (1996), Iles (2001), Moreau (1940, 1944), Ray (1968).