Comoros is one of the five ‘hottest’ biodiversity spots in the world due to its large number of unique species found nowhere else on the planet. The coastal and marine environment is rich and varied, with fringing coral reefs, mangroves, seagrass beds, beaches of black, red and white sand, lava flows, islets and submarine banks.
At least four ecosystems can be found in Comoros:
- coastal ecosystem types (mangroves, seagrass beds and coral reefs);
- a savanna shrub land ecosystem type;
- a forest ecosystem type; and
- a wetland ecosystem type.
Comoros has many endemic, threatened or migratory species such as sea turtles, whales, dolphins, lemur and dugong, and sea cucumbers.
The Comorian coral reefs are fringing reefs which constitute a narrow platform that only extends a short distance from the coast. The Comorian reefs occupy about 60% of Grande Comoro’s coast, 80% of the Anjouan coast and 100% of Mohéli’s coast. Basaltic rocky reefs are also found in Comoros. There is vast coral reef coverage around the Sima peninsula, though live hard coral cover and fish abundance and richness varies widely.
Eight seagrass species are found in the Comoros. Extensive seagrass beds are found in the Mohéli Marine Park, which harbors almost 90 per cent of the seagrasses in the country. The remaining area is made up of seagrass beds located at Mitsamiouli, Malé and Ouroveni in Grande Comoro and at Bimbini and Ouani in Anjouan.
Comoros seagrasses have been affected by sedimentation and climate change. For example, T. ciliatum beds in Mohéli Marine Park were destroyed by high sediment influx into the lagoon from upland deforestation, coupled with high rainfall, which took place between 1993 and 1998.
Mangroves are present in few locales, but cover appears to be stable. The Comoros harbor about 120 ha of mangroves, with about 75 per cent of these occurring on the south coast of Moheli Island, especially in the region of Damou and Mapiachingo. Other mangrove areas include Grande Comore and Anjouan. Seven species occur in the Comoros, the most abundant being R. mucronata and A. marina.