Monitoring of marin habitats
The Nature Reserve of Saint-Bartholomew protects underwater ecosystems. Seagrass beds (flowering underwater plants) and coral reefs are home to an exceptional biodiversity. The Nature Reserve’s role is not confined to protection: it also aspires to understand the evolution of these habitats. That’s why scientific monitorings are developed. They allow to monitor the health of these habitats and to highlight the effect of protective measures.
Since 2002 the Nature Reserve of Saint-Bartholomew works with the marin biologist team of Professor Claude Bouchon from the university of Antilles-Guyane. This group studies the evolution of benthic communities (seagrass, coral reefs) in Reserve area but also outside, trying to find out a reserve effect. Centimeter by centimeter, the team observes the dynamics of corals, coutns sea urchins and algae. Seagrass is another important natural environment. They are home to many endangered species (conch, turtle) and serves as a nursery. During the scientific monitoring, the density of the herbarium, the length of the leaves, the presence and size of conch were observed.
Researchers from the University of the Antilles and Guyana have also initiated monitoring of fish. 107 species were recorded between 2002 and 2008 to Ilet Coco and Pain de Sucre. In 6 years, more and more different species frequented these places. The fish do not seem affected by coral mortality. Perhaps because their shelters have not yet been degraded.
In the beginning, the monitoring was bi-annual. It allowed to highlight seasonality: the composition of benthic communities changes according to the seasons. Monitoring now takes place once a year.
After ten years of observation, the reserve effect seems demonstrated. The number of underwater organisms (biomass) and the size of individuals increased in protected areas.
These statistics, performed on 5 to 10 years, also show that the rate of recovery of coral is stable, after a significant decline in 2005 due to a warming waters (a phenomenon of coral bleaching was observed). To Coco and Pain-de-sugar, an average of 27 species of corals have been identified. This is a high value for a caribbean station! Outside the reserve, however, coral reefs are declining.
Conch are fewer and fewer ... This is what was observed in Marigot between 2007 and 2008. The decrease is due to their migration, but also due to poaching. Selective fishing has been set up in Saint Bartholomew, only large individuals are captured.
A cartografy of these areas was completed in 2001 by Sylvain Chauvaud and renewed 10 years later.
A partnership is established between the Natural Reserves of the northern islands of the West Indies, to harmonize monitorings. This network aims to train staff to the simplified monitoring protocols. This is another opportunity for the Natural Reserve of Saint-Bartholomew to explore underwater ecosystems.
The coral reefs of Colombier and beef are studied. The results show an increase in the presence of coral by 9% between 2007 and 2008, no significant bleaching.
Coral reefs are now enrolled in national monitoring networks (French Initiative for Coral Reefs, IFRECOR) and international network (Global Coral Reef Monitoring Network, GCRMN).