The activities are as follows:
- Teacher Guide
- Student activity, Graph Type A, Level 3
- Student activity, Graph Type B, Level 3
- Student activity, Graph Type C, Level 3
- Grading Rubric
Humans are changing the earth in many ways, including warming the planet by burning fossil fuels and adding greenhouse gasses to the atmosphere. Scientists have documented rising temperatures across the globe and predict an increase of 3° C in Michigan within the next 100 years. Humans are also changing the earth by transporting species across the globe, introducing them into new habitats. These introduced species may cause problems in their new habitats. Additionally, increasing temperature from climate change may change the way that native and introduced plants and animals interact.
All living organisms have a range of temperatures they are able to survive in, and temperatures where they perform their best. For example, arctic penguins do best in the cold, while tropical parrots prefer warmer temperatures. The same is true for plants. Depending on the temperature preferences of a plant species, warming temperatures due to climate change may either help or harm that species.
Scientists are concerned that invasive species may do better in the warmer temperatures caused by climate change. Invasive species have been introduced from one area into another, and now thrive in their new habitat. Invasive species harm native species and cause many problems for humans. There are several reasons to expect that invasive species may benefit from climate change. First, because invasive species have already survived transport from one habitat to another, they may be species that are better able to handle change, such as temperature changes. Second, the new habitat of an invasive species may have temperatures that allow it to survive, but are too low for the invasive species to do their absolute best. This could happen if the invasive species was transported from somewhere warm to somewhere cold. Climate change could increase temperatures enough to put the new habitat in the species’ range of preferred temperatures, making it ideal for the invasive species to grow and survive.
To determine if climate change will benefit invasive species, scientists at Michigan State University focused on one of the worst invasive plants in Michigan, Centaurea stoebe (spotted knapweed). They looked at Centaurea plants growing in a field experiment with eight rings. Half of the rings were left with normal, ambient air temperatures. The other half of the rings were heated using ceramic heaters attached to the side of the rings. These heaters successfully raised air temperatures by 3° C. At the end of the summer, the scientists collected all of the Centaurea plants from the rings. They recorded both the (1) abundance, or number of Centaurea plants within a square meter, and (2) the biomass (dry weight of living material) of the plants in a square meter as a measure of performance.
Featured scientists: Katie McKinley, Mark Hammond, and Jen Lau from Michigan State University