Genetic diversity and population structure in Nothofagus pumilio, a foundation species of Patagonian forests: defining priority conservation areas and management

M Gabriela Mattera,M Victoria Lantschner,Carolina Soliani,Mario J Pastorino,Paula Marchelli

doi:10.1038/s41598-020-76096-0

Abstract

Patagonian forests are the southernmost temperate forests in the world, and Nothofagus pumilio is one of their most ecologically important tree species (i.e., a foundation species). It presents great adaptability and a wide distribution range, making it a suitable model for predicting the performance of trees facing global climate change. N. pumilio forests are increasingly threatened by extreme climatic events and anthropogenic activities. This study aims to identify priority conservation areas and Genetic Zones (GZs) for N. pumilio, promoting the implementation of specific practices to ensure its management and long-term preservation. Thirty-five populations (965 trees) sampled across its distribution (more than 2200 km latitudinally) were genotyped with SSRs, and geographical patterns of genetic variation were identified using Bayesian approaches. The phylogeographic patterns of the species and geomorphological history of the region were also considered. Six priority conservation areas were identified, which hold high allelic richness and/or exclusive allelic variants. Eighteen GZs were delineated based on the genetic structure of this species, and maps showing their distributional range were drawn up. Overall, this study defines management units based on genetic data for N. pumilio for the first time, which will facilitate the establishment of sustainable practices and highlight priorities for investment of conservation funding.

Highlights

Patagonian forests are the southernmost temperate forests in the world, and Nothofagus pumilio is one of their most ecologically important tree species
A second, well-known alternative for operational genetic management units (OGMUs) delineation is the definition of Provenance Regions (PRs), which aims to ensure the safe transference of propagation material without risk of maladaptation since it is based on variation in adaptive c haracters[27]
Several authors have suggested that areas containing high allelic richness and/or exclusive allelic variants are meaningful for conservation p urposes[30,31,32], because they play a key role as genetic diversity reservoirs or sources of locally-adapted genotypes

Summary

Introduction

Patagonian forests are the southernmost temperate forests in the world, and Nothofagus pumilio is one of their most ecologically important tree species (i.e., a foundation species). Nothofagus pumilio, commonly called lenga, is one of the most important species of Patagonian forests, since it has the largest distribution area of all native trees in the region, covering about 1.636 million hectares and occupying a range of about 20° latitude (from 36°S to 55°S) in Argentina. This species has a similar distributional range to the west of the Andes mountain range, in C hile[11]. Several authors have suggested that areas containing high allelic richness and/or exclusive allelic variants are meaningful for conservation p urposes[30,31,32], because they play a key role as genetic diversity reservoirs or sources of locally-adapted genotypes

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Results