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The loggerhead sea turtle (Caretta caretta), has the broadest distribution among sea turtle species in the Mediterranean and requires regional and international collaborations in addition to local efforts to better inform conservation actions. Molecular techniques are powerful tools to assess population dynamics at large scales, especially by determining the connectivity among different nesting and foraging sites, and genetic diversity. In this study, a large sample was collected synchronously in the nesting areas located in the north, south and east of the Mediterranean. Recently described nesting sites from Albania and other nesting sites represented by lower sample size were also included in order to fully assess the genetic composition of the region's rookeries. Samples from 710 individuals were collected and the longer (815 bp) mtDNA D-loop fragment of these samples was ampli ed. We recorded 15 haplotypes, three of which were novel. In addition, our results show that some haplotypes, considered of Atlantic origin, have a wider dispersal in the Mediterranean than previously thought, albeit with low levels of representation. Our results, which also contribute to determining the likely origin of haplotypes that were previously known only from foraging sites, highlight the utility of broad-scale sampling, with increased sample number and longer mtDNA sequence to determine genetic diversity and connectivity. This study also demonstrates that it is important to continue to monitor the contribution of Atlantic origin haplotypes to the Mediterranean population, and the resident Mediterranean population, which is expected to expand its geographical range for reproduction with the effect of climate change and climate change in the long term. This work is important for, among other things, mixed stock analyses (MSA) that seek to localize the origin of stranded or accidentally caught sea turtles or those purposefully obtained from foraging sites to better understand the migratory distribution for conservation purposes.

1. In biodiversity monitoring, large datasets are becoming more and more widely available and are increasingly used globally to estimate species trends and conservation status. These large-scale datasets challenge existing statistical analysis methods, many of which are not adapted to their size, incompleteness and heterogeneity. The development of scalable methods to impute missing data in incomplete large-scale monitoring datasets is crucial to balance sampling in time or space and thus better inform conservation policies. 2. We developed a new method based on penalized Poisson models to impute and analyse incomplete monitoring data in a large-scale framework. The method allows parameterization of (a) space and time factors, (b) the main effects of predictor covariates, as well as (c) space-time interactions. It also benefits from robust statistical and computational capability in large-scale settings.3. The method was tested extensively on both simulated and real-life waterbird data, with the findings revealing that it outperforms six existing methods in terms of missing data imputation errors. Applying the method to 16 waterbird species, we estimated their long-term trends for the first time at the entire North African scale, a region where monitoring data suffer from many gaps in space and time series.4. This new approach opens promising perspectives to increase the accuracy of species-abundance trend estimations. We made it freely available in the r package

The loggerhead sea turtle (Caretta caretta), has the broadest distribution among sea turtle species in the Mediterranean and requires regional and international collaborations in addition to local efforts to better inform conservation actions. Molecular techniques are powerful tools to assess population dynamics at large scales, especially by determining the connectivity among different nesting and foraging sites, and genetic diversity. In this study, a large sample was collected synchronously in the nesting areas located in the north, south and east of the Mediterranean. Recently described nesting sites from Albania and other nesting sites represented by lower sample size were also included in order to fully assess the genetic composition of the region’s rookeries. Samples from 710 individuals were collected and the longer (815 bp) mtDNA D-loop fragment of these samples was amplified. We recorded 15 haplotypes, three of which were novel. In addition, our results show that some haplotypes, considered of Atlantic origin, have a wider dispersal in the Mediterranean than previously thought, albeit with low levels of representation. Our results, which also contribute to determining the likely origin of haplotypes that were previously known only from foraging sites, highlight the utility of broad-scale sampling, with increased sample number and longer mtDNA sequence to determine genetic diversity and connectivity. This study also demonstrates that it is important to continue to monitor the contribution of Atlantic origin haplotypes to the Mediterranean population, and the resident Mediterranean population, which is expected to expand its geographical range for reproduction with the effect of climate change and climate change in the long term. This work is important for, among other things, mixed stock analyses (MSA) that seek to localize the origin of stranded or accidentally caught sea turtles or those purposefully obtained from foraging sites to better understand the migratory distribution for conservation purposes.

No abstract