Forest Ecology and Management 481 (2021) 118716 Available online 28 October 2020 0378-1127/© 2020 Elsevier B.V. All rights reserved. Spatiotemporal variation in mating system and genetic diversity of Araucaria angustifolia: Implications for conservation and seed collection Newton Cl´ ovis Freitas da Costa a, b, * , Lilian Iara Bet Stedille b , Miguel Busarello Lauterjung a , Tiago Montagna a , Rafael Candido-Ribeiro a, c , Alison Paulo Bernardi a , Adelar Mantovani b , Mauricio Sedrez dos Reis a , Rubens Onofre Nodari a a Núcleo de Pesquisas em Florestas Tropicais (NPFT), Universidade Federal de Santa Catarina, Rodovia Admar Gonzaga 1346, Florian´ opolis, Brazil b Uso e Conservaç˜ ao dos Recursos Florestais (UCRF), Universidade do Estado de Santa Catarina, Avenida Luís de Cam˜ oes 2090, Lages, Brazil c Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada A R T I C L E INFO Keywords: Araucaria forests Spatial genetic structure Grasslands Small patches Isolated trees ABSTRACT Understanding spatiotemporal variations in genetic diversity and mating system can allow policymakers to better support actions towards conservation and management of plant populations. However, multiyear studies are still scarce for many long-lived tree species. Therefore, we herein analyze how genetic diversity, genetic structure and mating system of Araucaria angustifolia vary within and among populations, generations (adults and seed co- horts) and years. We evaluated two A. angustifolia populations occurring in forest-grassland landscapes, one of them for three years. Differences in Ho and He were observed among generations and populations, with sig- nifcant fxation indexes for all adult and seed cohorts evaluated. Pairwise F ST values showed that genetic di- vergences were greater between populations, followed by those among years, and, fnally, less relevant values among generations. No signifcant spatial genetic structure was found in either population. Paternity correlation, number of pollen donors, coancestry and proportion of half and full-sibs may vary over the years in A. angustifolia. In practical terms, the present study demonstrates how recommendations for seed collection may change according to the evaluated year, such as the number of seed trees, which ranged from 42 to 48. Furthermore, multiyear analyses allow a more comprehensive understanding of the genetic aspects for a long- lived tree species. Finally, we present and discuss these aspects and their variations in space, time and be- tween reproductive events, including recommendations for seed collection. 1. Introduction Conservation and management practices of natural populations of trees have long benefted from studies involving different aspects of genetic diversity (Bittencourt and Sebbenn, 2007; Aguilar et al., 2008; Sebbenn et al., 2011; Lanes et al., 2016; Montagna et al., 2018b; Ramos et al., 2018). In these studies, questions related to the magnitude of genetic diversity and the variation within and between populations generally have direct implications for conservation practices (Lowe et al., 2018; Lauterjung et al., 2019). In a fne-scale analysis, spatial genetic structure (Chung et al., 2003; Vekemans and Hardy, 2004; Hardy et al., 2006) can be used to inform minimum distances of seed collection for ex situ conservation or genetically-sound restoration programs (Buzatti et al., 2012; Montagna et al., 2018a, 2019). Mating system analysis is also a way of trying to understand how genetic ex- change among plants infuences the organization of genetic diversity in plant populations. By assessing genotypes of multiple seed trees and their progeny, one can estimate the minimum required number of seeds to collect and from how many mother-trees in order to achieve an acceptable effective population size (Ne) (Ritland and Jain, 1981; Rit- land, 1985; Eckert et al., 2010). Genetic studies on key species of forest ecosystems helped to unravel effects of anthropogenic habitat modif- cations and their consequences, such as reduction in effective popula- tion sizes, increase of inbreeding effects, and potential negative implications for species genetic parameters (Ouborg et al., 2006; Vranckx et al., 2014). * Corresponding author at: Uso e Conservaç˜ ao dos Recursos Florestais (UCRF), Universidade do Estado de Santa Catarina, Avenida Luís de Cam˜ oes 2090, Lages, Brazil. E-mail addresses: newton_eu16@hotmail.com (N.C.F. Costa), rafael.ribeiro@ubc.ca (R. Candido-Ribeiro), bernardialison@gmail.com (A.P. Bernardi), msedrez@ gmail.com (M.S. Reis). Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco https://doi.org/10.1016/j.foreco.2020.118716 Received 8 February 2020; Received in revised form 9 July 2020; Accepted 15 October 2020