Ecological insights and management implications of the global migratory connectivity of green turtles

Abstract

AimGreen turtles are a widely distributed and highly migratory species, despite extensive data on the movement of green turtles, there is no global synthesis on the subject, limiting a holistic understanding of their movement. Based on three decades of published literature, we present the first global model of migratory connectivity for green turtles. LocationGlobal. Time Period1990-2022. Major Taxa StudiedGreen Sea Turtle (Chelonia mydas) MethodsWe conducted a structured literature review extracting georeferenced information on the movement of green turtles from 1990 to 2022, aggregating this information into a single connectivity model, defining sites and "metasites" as nodes of connectivity. We then evaluate the connectivity routes from nesting areas to foraging sites for each RMU, identifying those trajectories moving outside and across the boundaries of these areas. ResultsWe found an increasing number of studies assessing movement of green turtles, with a total of 113 sources of migratory connectivity information. We identified 474 sites, representing locations where green turtles were observed (124 of these being nesting sites). Migratory connections from nesting sites ranged from resident turtles never leaving the area, to rookeries linked to 13 different sites, some over 5,000 km apart. This long-distance connectivity exposes populations to threats across disparate locations. Most connections traversed national jurisdictions, including crossing different Regional Management Units Main ConclusionsWe compiled the largest available dataset describing movement of green turtles worldwide and present the first global model of their migratory connectivity. This model provides ecological insights into regional differences in life histories, identifies geographic and demographic gaps in sampling, and provides baseline information on connectivity to support transboundary management of green turtle populations. The study highlights the need for larger collaborative efforts to aggregate knowledge beyond local jurisdictions, to inform and align effective management measures to protect this threatened species.