Research Results Guide Turtle Protection in Baja California Sur, Mexico

Sprawling beachfront development in Cabo San Lucas, Mexico, leaves little undisturbed habitat for nesting turtles. © Phillip Colla

Sprawling beachfront development in Cabo San Lucas, Mexico, leaves little undisturbed habitat for nesting turtles. © Phillip Colla

By STEPHANIE ROUSSO and CARLA SANCHEZ

At the southern tip of the Baja California peninsula, Los Cabos is one of the fastest growing coastal tourism destination centers in Mexico. It is also home to the northernmost primary nesting beach for olive ridleys in the eastern Pacific, and hosts some leatherback and green turtle nesting too. The coastline of Los Cabos is already highly developed, and coastal hotels and resorts have grown an additional 15 percent since 2009. While poaching and bycatch are significant threats to sea turtles in the region, coastal development and its impact on nesting beaches pose the greatest threats.

The coastal development taking place in Los Cabos consists predominantly of multi-use megaresorts and residential neighborhoods with multiple single-family lots. One such megaresort, the 610-hectare luxury Diamante Beach and Golf Resort, is a perfect example of the potential impact of coastal development on sea turtle nesting habitat. Located on the beach approximately 10 kilometers north of Cabo San Lucas, Diamante Resort, which is currently under development, boasts 40 one-acre beach estate sites. These homes will bring new artificial lighting, desalination plants, and human activity to the beach, ranging from all-terrain vehicle and horseback-riding tours to shore-fishing, all of which have the potential to adversely impact sea turtle habitat and nesting activity. The cumulative effects from multiple single-family lots can be just as great as from a megaresort.

The typical method of coastal development has been to level the coastal dunes to construct the infrastructure. But such dune removal essentially eliminates the sediment reservoir needed to replenish nesting beaches after the storm season. In response to concerns about the unregulated coastal development promoted by the Mexican Secretary of Tourism (FONATUR) and generally poor habitat management practices in the region, environmental organizations held multiple public workshops about the future conservation of coastal dunes and wetlands of northwest Mexico. Building on the workshops, the Federal Secretary of Environment (SEMARNAT) published a management plan for coastal dunes in 2013. In the plan they specifically cite two federal regulations protecting sea turtles, which detail the importance of healthy dune habitats in supporting successful sea turtle nesting.

For more than 19 years, our organization, ASUPMATOMA A.C., has monitored 21 kilometers of coastline in the Pacific region of Los Cabos. Over the past two years we began evaluating olive ridley nest distribution and density in relation to dune-backed beach profiles. By comparing developed areas with undisturbed areas, we analyzed the impacts of dune removal and related erosion on sea turtle nesting. We found that over the past 18 years, nest density has been on average 43 percent greater in the undisturbed nesting area than in the developed area. Results from the 2013 nesting season (N = 438) also show that more than 52 percent of olive ridley nests occur between 60 and 90 meters from the shore, although the Federal Maritime Protection Zone (ZOFEMAT) extends only 20 meters from the shore. These findings are allowing us to create region-specific scientific recommendations for balancing conservation with tourism development, such as a recommendation to extend the ZOFEMAT. While coastal development poses a significant threat to sea turtles in Los Cabos, we are hopeful that our research will be used to guide improved development practices here and that our experiences can serve as an example for other coastal areas.