Environmental gradients as “natural labs” for elucidating the regeneration dynamics of three Nothofagus species under different climatic scenarios in Patagonia

Abstract

We work in Patagonian forests, the southernmost woody ecosystems of the world, in which three tree species have a clear altitudinal distribution. Nothofagus obliqua is frequent at 650-850 m above the sea level, N. nervosa at 900-1000 m and N. pumilio is distributed above 1000 m up to the treeline. Temperature is the environmental factor that shows the strongest association with altitude. In this ecosystem, by coupling mathematical models with ecological data, we previously demonstrated that seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche and that this trait contributed to germination dynamics across altitude. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to early-spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude (Arana et al., 2016 New Phytologist 209:507).