Research by Queen’s PhD student Tara Zamin (Biology) investigates how and why vegetation is changing in the Arctic. The new data indicating that growth of tundra deciduous shrubs can be greatly stimulated by warmer temperatures supports satellite-based observations of increased greening as the region’s climate has warmed over the past few decades.

Such greening is of global significance because it means more incoming solar energy is absorbed by the earth’s surface rather than reflected back to space, and therefore tends to result in atmospheric temperature rises – a positive feedback to further warming.

“My research is a small piece of the puzzle but it shows that warming can result in substantial vegetation change,” says Ms. Zamin. “We need to be aware of things like this so we can anticipate and prepare ourselves for worldwide changes due to warmer temperatures.”

Ms Zamin spent three summers in the Arctic comparing the growth of tundra plants which were covered by plastic greenhouses with adjacent exposed plants. In addition to the warming experiment, she added nitrogen and phosphorus fertilizers to other plots.

“I was surprised that shrub growth was limited by both of these nutrients,” says advisor Paul Grogan (Biology). Most climate-related research has focused on nitrogen as the key element driving the functioning of low arctic ecosystems with the assumption that warming enhances nitrogen availability in the soil leading to increased plant growth. “For plants, the supply and acquisition of nitrogen and phosphorus are as different as meat and vegetables are to the human diet. Tara’s data clearly demonstrates that we must include phosphorus in future studies to more accurately understand and predict how and why arctic tundra vegetation is responding to climate warming."

Ms Zamin’s research was published in Environmental Research Letters.