Phenotypic plasticity and genetic adaptation in arctic plants in a warming climate: responses to long-term experimental and observed climate change

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Species have three options to deal with the changes in climate: adapt, migrate or go extinct. While the climate of the planet has gone through major changes in the past, the changes were relatively slow which allowed organisms with the right mix of genetic traits, to adapt and survive. However, the current warming, due to the increased emissions of greenhouse gases, is happening at a rate that has never been seen before, especially in the Arctic. The climate of the Arctic has already warmed by more than 1°C in the past 50 years. We do not know if tundra plant species have the ability to adapt to the rapid warming. We know that tundra plants responded as predicted when warmed in experiments or when measured over the past 20-30 years as the climate has warmed. Most plants flowered earlier, increased in growth and produced larger and better seeds in warmed environments. What we need to know is whether these changes in warmed plants are permanent, and if the plants in warmed plots continue to grow larger and produce better seeds even when they are grown outside the warmed plots. We will collect seeds from the major tundra plant species we have been following since 1992 in a set of warming experiments at a site on Ellesmere Island in the High Arctic. We will do the same at another experimental site in the Low Arctic, north of Yellowknife. The seeds will be germinated and seedlings grown in climate controlled chambers at the University of British Columbia where they will be allowed to flower and produce seeds. Seedlings from these second generation seeds will be planted into warmed and unwarmed plots at the research sites. If the plants from seeds that originally came from warmed plants continue to flower earlier, have larger leaves, and larger and better seeds than the plants from the unwarmed plots, then we will have very strong evidence that the plants have been able to adapt to the warmed conditions over the 19-20 years of the experiment. If there is no difference between the plants, then we can conclude that genetic adaptation to the warming has not (yet) occurred. This type of research is critical to understand and predict the future of tundra ecosystems in a warmer world.