Nothofagus pumilio is a common temperate tree species found in the southern portion of the Andes mountain range. Known locally as “lenga” (from the native Mapuche language), N. pumilio is a commercially important and scientifically interesting species. Of the seven Nothofagus species found in South America, N. pumilio has the most extensive distribution, spanning a latitudinal range from 36° to 54° S. It has adapted to survive in a wide variety of environmental conditions. It is a cold-tolerant and often high-elevation species that generally grows up to the treeline. However, at the highest and coldest latitudes of its range (i.e. Tierra del Fuego), it can also grow near sea level. It exists both in Valdivian (temperate) rainforests, where rainfall exceeds 3000 mm per year, and at the edge of the dry Patagonian steppe, where rainfall may only reach 300 mm per year.
Local environmental conditions such as temperature, precipitation, and day length are major drivers of evolutionary adaptation. The Andes mountain range, which is the longest on Earth and runs almost exactly north-to-south, provides a unique research opportunity for studying the effects of environmental conditions on local tree populations. By sampling N. pumilio individuals and populations along its entire distribution range, we can study the relationships between local environmental conditions (both current and past) and the genotypes and phenotypes currently found in N. pumilio.
The LocalAdapt project, which began in January 2019, aims to do just that. LocalAdapt is part of a new branch of tree research, combining the scientific disciplines of dendroecology and genetic analysis. We will analyze DNA samples from each individual using exome capture. Phenotype will be approximated using the relatively new discipline of dendrophenotyping, which focuses on tree ring chronologies. The first phase of the project involves sampling 500 individuals from 20 sites across the species’ range. Seventeen sites are paired, meaning two (and in one case three) sites are chosen within a single population – sites that are close enough to share gene flow but far enough to experience different environmental conditions and selective pressures. Two standalone “xeric” sites are located at the far eastern edge of the natural distribution, where preciptation is much lower than average, and the final site is located at the far northern edge, where only one environmental niche is present.
This project is part of an ongoing research partnership between Instituto Nacional de Tecnología Agropecuaria (INTA, Bariloche, Argentina) and Philips Universität (Marburg, Germany). Scientists at these institutions have been collaborating for the past two decades to study multiple Nothofagus species, including N.pumilio.
LocalAdapt also uses nearly identical research methods to the European- Union-centric GenTree project, which focuses on 7 common tree species across Europe. Data collected on N. pumilio will be analyzed in conjuction with data collected in GenTree, to determine whether there are patterns of convergent evolution between closely- and distantly-related species in Patagonia and Europe.