Search

7 Pág. Instituto de Ciencias Forestales (ICIFOR), Estimates of contemporary effective population size (Ne) can provide valuable information for genetic conservation and monitoring, pinpointing populations at higher risk of genetic erosion, decreased fitness, maladaptation and, ultimately, demographic decline. There are however potential limitations in the application of commonly employed genetic estimators of contemporary Ne to widespread forest tree populations. Genetic isolation by distance within populations, small and spatially restricted samples, among-population gene flow and overlapping generations are factors that can potentially affect the accuracy of marker-based estimates of contemporary Ne, depending on the demographic scenario. In particular, we illustrate the uncertainty faced by forest researchers and managers when interpreting contemporary Ne estimates obtained for continuously distributed tree populations with large census size N. To that end, we use previously published genotypic data of 21 Pinus pinaster populations, including distinct sampling schemes, together with a widely used method based on linkage disequilibrium patterns observed in a single (one-time) population sample. We hypothesize that spatially restricted sampling might be the main putative factor behind the apparently low Ne/N estimates obtained for the large and continuously-distributed populations studied here. Because of its statistically-inherent assessment difficulty, we call for caution when interpreting marker-based estimates of contemporary Ne for monitoring widely-distributed tree populations or small genetic conservation units embedded within large continuous tree populations., This work was supported by the Spanish Ministry of Agriculture, Fisheries and Food (MAPAMA) [grant number AEG 17-048] in the frame of the measure 15.2 “support to the conservation and use of forest genetic resources” and under Regulation (EU) No 1305/2013 of the European Parliament and of the Council of 17 December 2013 on support for rural development by the European Agricultural Fund for Rural Development (EAFRD) with 75 % co-financing. This paper was also supported by the European Union 's Horizon 2020 research and innovation programme [grant agreement No 862221 (FORGENIUS)]. We thank two anonymous reviewers for their constructive criticism.