Living on the edge: adaptive and plastic responses of the tree Nothofagus pumilio to a long‑term transplant experiment predict rear‑edge upward expansion

MATHIASEN, PAULA; PREMOLI, ANDREA C.

OECOLOGIA

SPRINGER

Lugar: Berlin; Año: 2016

0029-8549

Current climate change affects the competitive ability and reproductive success of many species, leading to local extinctions, adjustment to novel local conditions by phenotypic plasticity or rapid adaptation, or tracking theiroptima through range shifts. However, many species have limited ability to expand to suitable areas. Altitudinal gradients, with abrupt changes inabiotic conditions over short distances, represent ?natural experiments?for the evaluation of ecological and evolutionary responses under scenariosof climate change. Nothofagus pumilio is the tree species which dominates as pure stands the montane forests of Patagonia. We evaluated the adaptive valueof variation in quantitative traits of N. pumilio under contrasting conditionsof the altitudinal gradient with a long-term reciprocal transplant experimentaldesign. While high-elevation plants show little response in plant, leaf, and phenological traits to the experimental trials, low-elevation ones show greaterplasticity in their responses to changing environments, particularly at high elevation. Our results suggest a relatively reduced potential for evolutionaryadaptation of high-elevation genotypes, and a greater evolutionary poten-tial of low-elevation ones. Under global warming scenarios of forest upslope migration, high-elevation variants may be outperformed by low-elevation ones during this process, leading to the local extinction and/or replacement of thesegenotypes. These results challenge previous models and predictions expected under global warming for altitudinal gradients, on which the leading edge is considered to be the upper treeline forests.