Wildlife of
Seychelles

Primary Threats

• Climate change is a primary driver of coral reef stress in Seychelles, with marine heatwaves causing mass coral bleaching (historically severe events including 1998 and subsequent episodes) that reduce reef complexity, fish habitat, and coastal protection. Sea-level rise threatens low-lying coral atolls and nesting beaches (e.g., for turtles and seabirds), while warmer temperatures and altered rainfall can affect freshwater availability and increase erosion/landslides on steep granitic islands during extreme rainfall events.
• Invasive plants and animals are a major island-biodiversity threat. Rats, feral cats, and invasive ants can predate on eggs/chicks of endemic birds and seabirds and disrupt invertebrate communities; invasive plants (e.g., aggressive shrubs/vines) can outcompete native forest species and degrade habitat in key reserves. Biosecurity is challenging across many islands and islets, and reinvasion risk is ongoing due to inter-island transport and tourism.
• Terrestrial habitat loss is concentrated on the main inhabited granitic islands where limited flat land drives conversion of coastal plains and lower slopes for housing, roads, tourism facilities, and utilities. Coastal wetlands, dune systems, and native lowland forests have been reduced or fragmented, affecting endemic birds, reptiles, and plant communities and increasing edge effects and erosion.
• Pollution issues include marine plastics and derelict fishing gear washing onto beaches and outer islands, localized eutrophication and bacterial contamination from wastewater/septic leakage near dense settlements, and runoff from construction and roads that increases sedimentation on nearshore reefs and seagrass beds. Solid-waste management constraints on small islands amplify leakage into the ocean, especially during heavy rains and storms.
• Fishing pressure-particularly on tuna (industrial/foreign fleets) and reef-associated species (artisanal)-can reduce biomass and alter food webs, with additional risks from bycatch (e.g., sharks, turtles, seabirds) and concentrated pressure near accessible reefs. Managing a very large EEZ with limited enforcement capacity increases vulnerability to IUU fishing and complicates stock sustainability and ecosystem-based management.
• Tourism and recreation can disturb sensitive nesting and roosting sites (seabird colonies, turtle nesting beaches) through beach lighting, trampling, noise, and boat traffic. High visitation to iconic natural sites (e.g., coral reefs, Vallee de Mai) requires continuous management to prevent trail erosion, wildlife stress, and degradation of fragile habitats.
• Coastal infrastructure (ports, seawalls, land reclamation, airports, roads) can directly remove or fragment habitats and change sediment dynamics, increasing erosion and reef sedimentation. Climate adaptation infrastructure (hard coastal defenses) may unintentionally squeeze beaches and intertidal habitats, reducing space for natural coastal ecosystems to migrate inland.
• Alteration of natural coastal and watershed processes-such as channelization/drainage, sand extraction restrictions shifting pressures elsewhere, and shoreline armoring-changes sediment transport and can degrade lagoons, mangroves where present, and nearshore reef conditions. On some islands, historical land uses and fire have modified native forest structure, necessitating active restoration to re-establish ecological function.
• Urban expansion around Victoria and peri-urban growth on Mahé and other inhabited islands increases demand for land, water, and waste services, creating cumulative impacts on nearby terrestrial reserves and coastal waters. Increased impervious surfaces intensify stormwater runoff and pollution loads to reefs and bays.
• Pressure on limited freshwater resources and coastal resources (sand, nearshore fish, and lagoon ecosystems) is heightened by population concentration and tourism demand. During droughts or heat extremes, water scarcity can increase reliance on energy-intensive desalination and strain watershed management, while localized overuse of coastal resources can reduce resilience of reef and lagoon systems.