Effective monitoring programs are required for early detection of population declines, especially in species with low effective to census population size ratios, in which genetic erosion will precede apparent declines in abundance. Calculation of effective population size (Ne) is thus crucial in genetic monitoring programs, but the accuracy of estimates depends on 1) the amount of marker information and 2) the power of the used method and the suitability of its underlying assumptions to the targeted species. Its estimation and interpretation is especially complex in iteroparous species with overlapping generations, as is the case in most vertebrates. In amphibians, calculation of the effective number of breeders (Nb, a parameter that summarizes some of the information of Ne) can be more readily accomplished by means of sibship assignment analysis. This method is powerful, capable of producing unbiased estimates based on pedigree reconstruction and can accommodate to a wide variety of molecular data and mating systems, and account for genotyping errors. Accuracy of estimates is dependent on the correct reconstruction of pedigrees, which can be hindered when genetic information is scarce and the individuals in the sample are weakly related. In this talk, we argue that pedigree reconstruction can be critically enhanced by a thorough exploration of the mating system of the targeted species and the subsequent inclusion of this information in the analyses. We addressed these questions through the detailed monitoring of four species of pond-breeding amphibians based on direct (capturemark-recapture and counts of egg masses during a six-year period) and indirect (genotyping at 15-18 polymorphic microsatellite loci) methods. The sibship assignment method provided consistent estimates of Nb for two of the species, with inference of robust pedigrees greatly aided by the genotyping of both a cohort of larval samples and samples of candidate parents. The performance on the other two species was less robust, but was enhanced by the incorporation of prior information based on direct field data. Our integrative approach allowed characterization of the mating system of the study species, and showed wide variation in the levels of polygamy and in the respective Nb to census population size ratios. The results will be discussed in the general context of the design of efficient population monitoring programs taking advantage of molecular tools.

Resumen del trabajo presentado al XIV Congreso Luso-Español de Herpetología y XVIII Congreso Español de Herpetología: "Retos de la Herpetología en el siglo XXI", celebrado en Lleida (España) del 5 al 8 de octubre de 2016.-- et al.

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