Ecological Shifts under Climate Change in Boreal and Arctic Forests

Northern Research Station scientists are working with colleagues from Austria and the University of Oregon to study how different types of ecosystems across a wide area of Siberia might be affected by climate change. In the southern part of Siberia, taiga landscapes are dominated by trees, while in the northern part, tundra landscapes are dominated by shrubs. The research focuses on Siberia because there are no gradients like this in North America.

Climate change affects albedo, which is the brightness of the land. Albedo affects how much heat the planet absorbs from the sun. With climate change, the land in Siberia is expected to be less bright because snow will melt earlier each year and stay melted longer. This means it will absorb more heat, which could increase global warming.

The goal of the research is to find out when ecosystems might change with climate change, for example from tundra to forest, and to predict what types of trees and shrubs will grow where and how much carbon the trees will store. The scientists are interested in how changes in vegetation might affect the Earth’s climate.

This research is partially funded by the National Science Foundation.
 

Key Findings

Fire

• The model predicts that wildfires will get worse because of climate change. There will be more fires and a larger area burned each year, and individual fires will get bigger and burn hotter.
• The greatest increase in wildfires will be in the northern area of Siberia as the forests become denser. As climate change continues, the time between wildfires will get shorter.
• Even though the model predicts that more fires will happen with climate change, individual fires will be largest when the climate warms just a bit. As fires burn wood and leaves on the forest floor, the next fire will have less to burn.
• In the southern and mid-taiga landscapes, the model predicts that forests will change a lot because of more wildfires. Trees like larch and Scots pine will be replaced with ones that can resprout or regrow from seeds after intense fires, like birch and poplar.
• More fires mean that more young forests will develop across the whole region as older areas of forests burn

Albedo

• The computer modeling predicts that as the climate changes, the brightness of the land (albedo) in Siberia will decrease a lot, mainly because it will not be covered in snow for more of the year.
• This decrease in brightness could cause global warming equivalent to almost 7% of human-caused emissions.

The research team is looking at how fast temperatures are changing compared to how fast plants can move to new areas where the climate is better for them. They are using the LANDIS-II computer model to simulate how thawing permafrost affects factors like soil moisture and competition among different types of trees and shrubs. They are also looking at how disturbances like wildfires and insect outbreaks affect the forest on boreal and arctic landscapes.

Another part of the modeling work is looking at changes in albedo, the amount of sunlight that the landscape reflects. The scientists are using existing data from boreal forests to investigate changes in albedo.  

The research team is also planning to use computer models to predict how Siberian silk moth populations will change in different places as the climate changes.

This research will help scientists improve their computer models of vegetation and climate around the world. The research will also help us learn how changes in the environment are affecting other aspects such as fires and how seeds move around.