The potential effect of climate change on the establishment of invasive pines in Patagonia

Abstract

Climate change can enhance or hinder the spread of invasive plant species, as climatic conditions influence the population dynamics of invaders in their new range. Pines are one of the most widely distributed and problematic invasive tree species globally. Here we experimentally evaluated how two invasive pine species (Pinus ponderosa and Pinus contorta) respond to simulated climate change conditions in northwestern Patagonia. We conducted a full factorial manipulative field experiment with 3-year-old pine saplings growing in warmed (Open Top Chamber), watered, warmed + watered, and control treatments. In the warmed treatments P. contorta saplings showed lower survival and tended to grow taller while maintaining their root growth. In contrast, P. ponderosa saplings, which did not show differences in survival among treatments, did not vary their aerial growth under warmed conditions, but tended to increase their root-to-shoot ratio. Both species showed similar survival and growth in the watered treatments compared to the control, indicating that the implemented difference in water (ca. 30% during the growing season) had no significant effect. Our findings suggest that a decrease in the invasive capacity (initial stages) of P. contorta may occur under climate change but no significant changes are expected for P. ponderosa. This observed differential response may modify the current relative abundance of invading pine species in northwestern Patagonia and has implications for the response of invasive species to climate change elsewhere.