Protected areas host important remnants of marine turtle nesting stocks in the Dominican Republic

At a Conservation Crossroad: The Bahoruco-Jaragua-Enriquillo Biosphere Reserve in the Dominican Republic

This paper assesses the Dominican Republic’s willingness to pay (WTP) for a conservation, restoration, and sustainable development program for the Bahoruco-Jaragua-Enriquillo Biosphere Reserve (RBJBE). Created in 2002, the RBJBE covers approximately 4858 km2, of which approximately 900 km2 correspond to the sea surface. With three core conservation zones, the RBJBE constitutes a complex space with a history of conflicts rooted in exploiting natural resources and social and economic issues. At the same time, it is a biodiversity hotspot of global importance. We present a Contingent Valuation Method to estimate the WTP for a conservation and restoration program called PROBIOSFERA. The non-parametric and parametric estimates of the WTP are DOP 165.00 (≈USD 2.94) and DOP 181.88 (≈USD 3.25), respectively. The socioeconomic variables that positively affect the WTP are income level, educational level, and age. The ecosystem services that are statistically related to WTP are the provisioning and supporting services. Regardless of the monetary valuation scenarios defined, the estimated annual monetized aggregated welfare associated with the RBJBE for Dominican society is DOP 7.2 billion (≈USD 128.1 million).

Low Diversity and Strong Genetic Structure Between Feeding and Nesting Areas in Brazil for the Critically Endangered Hawksbill Sea Turtle

Marine turtle nesting areas are characterized by receiving several females every year. The species Eretmochelys imbricata, known as hawksbill turtle is listed as Critically Endangered by the IUCN, and has been the target of studies on genetic structure and population diversity in nesting areas. Therefore, this study aimed to analyze the genetic diversity and haplotype composition of populations sampled in nesting areas from the coast of northeastern Brazil based on the mtDNA D-loop region. We used genetic information and compared it with data from feeding areas available in public databases. We recorded a total of six exclusive haplotypes in the nesting areas and 27 exclusive haplotypes for the feeding areas. The H_1 haplotype was shared in all nesting areas. The turtles of these regions had a low diversity and a genetic structure composed of five divergent groups separating the reproductive areas from the ones of feeding areas. Positive and significant geographical distance relationships were also recorded with FST values (r = 0.2302, p = 0.007). Our results revealed that hawksbill turtles from reproductive areas comprise a single population that needs management strategies to protect the threatened species, in addition to providing information that contributes to future actions for the species conservation.

Nesting ecology and population trend of leatherback turtles Dermochelys coriacea at Pacuare Nature Reserve, Costa Rica

The leatherback turtle Dermochelys coriacea, the only extant species in its family, is categorized as Vulnerable on the IUCN Red List. The protection of nesting beaches and the associated conservation efforts along the Western Atlantic coast of Central America have improved the population trends of some of the most important rookeries. Here we report the life history, ecology and population trends of leatherback turtles over 18 years (1994–2012, excluding 1998) of effective protection in the Pacuare Nature Reserve, on the Caribbean coast of Costa Rica. A mean density of 142 nests per km, probably the highest in Central America, indicates the importance of this rookery within the Caribbean region. Long-term conservation efforts at the Reserve have significantly reduced poaching and contributed to maintaining a high level of hatchling production. Long-term monitoring has also facilitated estimation of relevant demographic parameters of the population, such as nesting success (mean 69.8 ± SD 7.3%), clutch size (which is positively correlated with female size), hatching success (mean 55.2 ± SD 6.0%), remigration interval (2.5 years), and growth rate of remigrant females (mean 0.3 ± SD 1.0 cm per year), which is slightly faster than growth rates reported for Pacific leatherback turtles. Overall, efforts at Pacuare have been successful in protecting leatherback turtles and understanding their life history, highlighting the importance of long-term conservation projects for maintaining threatened leatherback populations.

Assessing the efficacy of direct conservation interventions: clutch protection of the leatherback marine turtle in the Dominican Republic

The beaches of Jaragua National Park in the Dominican Republic are the country's last known major nesting site for the leatherback marine turtle Dermochelys coriacea. This nesting aggregation is threatened by widespread illegal egg take, and clutch relocation and artificial incubation have been carried out as protection measures since 1974. We assess the efficacy of such efforts and investigate how artificial incubation may be influencing the success and sex ratios of clutches. We compare hatching success, incubation duration and embryo mortality in in-situ clutches (n = 43) with those incubated artificially at sites in the east and west of the Park (n = 35 and n = 31, respectively). Our results show that in the west, artificial incubation significantly decreases hatching success in clutches. In the east the duration of incubation is increased, which we predict would result in an increase in the number of males from these clutches. Clutch relocation is currently the only viable conservation option for clutches on eastern beaches because of illegal egg take but action is needed to ensure that the natural sex ratio is not distorted. However, on the western beaches in situ clutch incubation seems possible through beach protection. Further community engagement and enforcement are required to improve conservation measures at eastern beaches if long-term, less sustainable intervention is to be avoided.

Genetic structure and natal origins of immature hawksbill turtles (Eretmochelys imbricata) in Brazilian waters

Understanding the connections between sea turtle populations is fundamental for their effective conservation. Brazil hosts important hawksbill feeding areas, but few studies have focused on how they connect with nesting populations in the Atlantic. Here, we (1) characterized mitochondrial DNA control region haplotypes of immature hawksbills feeding along the coast of Brazil (five areas ranging from equatorial to temperate latitudes, 157 skin samples), (2) analyzed genetic structure among Atlantic hawksbill feeding populations, and (3) inferred natal origins of hawksbills in Brazilian waters using genetic, oceanographic, and population size information. We report ten haplotypes for the sampled Brazilian sites, most of which were previously observed at other Atlantic feeding grounds and rookeries. Genetic profiles of Brazilian feeding areas were significantly different from those in other regions (Caribbean and Africa), and a significant structure was observed between Brazilian feeding grounds grouped into areas influenced by the South Equatorial/North Brazil Current and those influenced by the Brazil Current. Our genetic analysis estimates that the studied Brazilian feeding aggregations are mostly composed of animals originating from the domestic rookeries Bahia and Pipa, but some contributions from African and Caribbean rookeries were also observed. Oceanographic data corroborated the local origins, but showed higher connection with West Africa and none with the Caribbean. High correlation was observed between origins estimated through genetics/rookery size and oceanographic/rookery size data, demonstrating that ocean currents and population sizes influence haplotype distribution of Brazil's hawksbill populations. The information presented here highlights the importance of national conservation strategies and international cooperation for the recovery of endangered hawksbill turtle populations.

Contextualising the Last Survivors: Population Structure of Marine Turtles in the Dominican Republic

Nesting by three species of marine turtles persists in the Dominican Republic, despite historic threats and long-term population decline. We conducted a genetic survey of marine turtles in the Dominican Republic in order to link them with other rookeries around the Caribbean. We sequenced a 740bp fragment of the control region of the mitochondrial DNA of 92 samples from three marine turtle species [hawksbill (n = 48), green (n = 2) and leatherback (n = 42)], and incorporated published data from other nesting populations and foraging grounds. The leatherback turtle (Dermochelys coriacea) in the Dominican Republic appeared to be isolated from Awala-Yalimapo, Cayenne, Trinidad and St. Croix but connected with other Caribbean populations. Two distinct nesting populations of hawksbill turtles (Eremochelys imbricata) were detected in the Dominican Republic and exhibited interesting patterns of connectivity with other nesting sites and juvenile and adult male foraging aggregations. The green sea turtle (Chelonia mydas) has almost been extirpated from the Dominican Republic and limited inference could be made from our samples. Finally, results were compared with Lagrangian drifting buoys and published Lagrangian virtual particles that travelled through the Dominican Republic and Caribbean waters. Conservation implications of sink-source effects or genetic isolation derived from these complex inter-connections are discussed for each species and population.