Migratory Connectivity and the Conservation of Migratory Animals
Migration is the repeated seasonal movement to and from a breeding area. The linking of individuals or populations of a given species within its range, including its breeding, migration, and wintering areas, is known as migratory connectivity. In this Article, we discuss how new technologies and approaches are enhancing our knowledge of migratory connectivity, which in turn can improve our legal and policy approaches to the conservation of migratory animals. Advances in studying and documenting migratory connectivity require new approaches to the design and implementation of both domestic and international conservation efforts. Understanding migratory connectivity of different populations of species between specific geographic locations can also help build “social connectivity” for conservation—the cultural, educational, economic, and institutional linkages between these same locations that are a necessary foundation for effective and sustainable conservation efforts.
Origins of juvenile green sea turtles (Chelonia mydas) in the Bahamas: A comparison of recent and historical rookery contributions
Abstract Conservation of green sea turtles (Chelonia mydas) benefits from knowledge of population connectivity across life stages. Green turtles are managed at the level of genetically discrete rookeries, yet individuals from different rookeries mix at foraging grounds; therefore, rookeries may be impacted by processes at foraging grounds. Bimini, Bahamas, hosts an important foraging assemblage, but rookery contributions to this assemblage have never been resolved. We generated mitochondrial DNA sequences for 96 foraging green turtles from Bimini and used Mixed Stock Analysis to determine rookery contributions to this population using 817 and 490 base pair (bp) rookery baseline data. The MSA conducted with 817 bp data indicated that Quintana Roo, Mexico, and Central Eastern Florida contributed most to the Bimini population. The MSA conducted with 490 bp data indicated that Southwest Cuba and Central Eastern Florida contributed the most to Bimini. The results of the second MSA differ from a previous study undertaken with 490 bp data, conducted in Great Inagua, Bahamas, which suggested that Tortuguero, Costa Rica, contributed the most to that foraging assemblage. Large credible intervals in our results do not permit explicit interpretation of individual rookery contributions, but our results do indicate substantial relative differences in rookery contributions to two Bahamian foraging assemblages which may be driven by oceanic currents, rookery sizes, and possibly juvenile natal homing. Our findings may implicate a shift in contributions to the Bahamas over two decades, highlighting the importance of regularly monitoring rookery contributions and resolving regional recruitment patterns to inform conservation.
Population Surveys ( ground and aerial ) on Nesting Beaches
Nesting beach surveys are the most widely implemented monitoring tool in use by the global sea turtle community and are an important component of a comprehensive program to assess and monitor the status of sea turtle populations. These assessments are necessary to evaluate the effects of recovery and conservation activities which are being implemented at all life history stages. Appropriately designed nesting beach surveys, in concert with studies of nesting females (see Alvarado and Murphy, this volume; Balazs, this volume; Owens, this volume) and nest success (see Miller, this volume), can provide information relative to the number of nests deposited annually, the number of nesting females that are reproductively active annually, and annual nest productivity. Nesting beach surveys, as discussed in this chapter, refer to ground and/or aerial surveys conducted to gather information on the number of nesting and non-nesting emergences occurring on a nonarribada beach. Readers contemplating population surveys on mass nesting beaches should consult Valverde and Gates, this volume.