Drivers of wetland disturbance and biodiversity impacts on a tropical oceanic island

Wetlands are biologically important elements of landscapes and among the most threatened ecosystems on Earth. On the island of Mauritius, many remaining wetlands are being rapidly converted and fragmented by intense land-use demands. We surveyed 209 coastal wetlands on Mauritius to assess their biophysical attributes, land-use activities, and patterns of disturbance, to help identify factors that threaten wetland biodiversity. Most wetlands exhibited severe edge-related disturbances and more than half were fragmented. Plant species richness was highest in larger, unfragmented wetlands and lower in wetlands with degraded margins. Urban wetlands were smaller and more likely to be fragmented than those adjoining other land uses such as grazing and agriculture. Flooding of urban homes and infrastructure was more likely to occur near fragmented than natural wetlands. Ongoing wetland decline in Mauritius not only contributes to the loss of local biodiversity but reduces the larger ecosystem role these habitats play in regulating surface water and protecting adjacent marine habitats.

► We examined more than 200 Mauritian wetlands.
► Most wetlands showed severe edge disturbance and more than half were fragmented.
► Plant species richness was higher in larger, unfragmented wetlands.
► Urban wetlands were often smaller and fragmented compared to other sites.
► Flooding of homes and infrastructure was more likely near fragmented wetlands.