1. Climate Change, Grass Phenology, and Elk in the Yellowstone Ecosystem
Today we are going to be learning about how the timing of grass green-up or phenology (write on board) affects elk migration. We are going to think about how climate change may affect these patterns and will be doing our own research to predict how it may affect elk.

2. Paradise Valley, Montana
The Paradise Valley of Montana is part of the Greater Yellowstone Ecosystem. It is just outside of Yellowstone National Park and is home to many cattle ranches, private homes, and forest service area. It is also a critical part of the ecosystem for elk, who depend upon its grass in the winter months where it is much warmer than the higher peaks in the park. Understanding elk migration in this area is important for elk conservation and for ranchers who live alongside elk in this area.

3. Elk Migration
Elk in the northern range of Yellowstone National Park are migratory, meaning that they move from one location to another throughout the year. What factors do you think cause elk to migrate? (answers: weather, food, predators) Yes, all of those factors play a part. But today we are going to talk about what role grass (their food) plays in migration.

4. Grass phenology affects elk migration
Phenology= timing of green-up (think spring!)
Elk follow green-wave of grass up elevation from spring to fall
Grass phenology plays a big role in dictating elk migration. Elk move from low elevations in the winter and early spring to higher elevations following a green wave of grass caused by the melting of the snow. Elk are always looking to maximize the amount of green grass they are eating because it is believed to be more nutritious than brown dry grass.

5. Early spring: green grass in low elevations and agriculture
Here is a picture of the paradise valley in the early spring. As you can see, the greenest grass is at low elevations in the valley basin. There are also a lot of ranches with irrigated agriculture. Where would you expect elk to be in this picture? (the greenest grass at low elevations)

6. Mid Summer: Green wave starts to move up in elevation
Here is a picture of the paradise valley in mid summer. You can see that the snow has melted and the greenest grass is moving up in elevation. Where would you expect elk to be in this picture? ( really anywhere, but most likely on the greenest grass up the mountain)

7. Late summer: greenest grass is at high elevations
This is a picture of the paradise valley in late summer. Where would you expect the elk to be in this picture? (Probably in the green grass at the highest elevation)

8. What will happen with Climate Change?
Earlier spring
Shorter growing season
What will happen with to the elk?
Many researchers are concerned that climate change may affect the patterns of green-up that we just saw. They expect to see earlier spring greening, which may shorten the growing season. What do you think this will do to the elk?

9. Couch Potato Elk
Many people are afraid that it will cause elk to eat the grass in agriculture fields when the green grass is no longer available on the elevation gradient. Possibly we will get “couch potato elk” which are elk that just stay in the agriculture fields all year instead of migrating. What would happen if elk did this?

10. One major challenge that researchers have when studying elk is that it is hard to predict and see how grass is changing over such a large scale. Many scientists have recently been interested in what information we can get from satellite pictures of the reflectance of the earth. An instrument on a satellite called MODIS takes pictures of the reflectance of the earth’s surface everyday. They have found that looking at a combination of two bands of reflectance (NDVI) can actually tell us about how green the grass is.
Piekielek 2012

11. This NDVI map represents the timing of the start of green-up in this season.
This is a map that shows us where on the landscape you see grass greening at different times. The grey represents the elevation gain. You can see that the low elevations green up earlier than the high elevations. This map was made by Nate Piekielek (2012).
Piekielek 2012

12. Does this help us understand elk migration?
So how do we know what elk are eating? Just like with studying grass phenology, studying elk is difficult over such a large area. So to get an estimate of what elk are eating across a large area, we can do transects. Transects are random lines placed in a landscape. By running a transect and counting the total amount of elk scat and doing an assessment on the scat we can determine what kind of grass they are eating.

13. How do we know what stage of grass the elk are eating? Chlorophyll
So how do we know what stage of grass the elk are eating. Chlorophyll. Chlorophyll is a green pigment found in all green plants that plays a key role in converting sun energy into energy that can be used by the plant. The greener the grass, the more chlorophyll is present. Therefore, if we look at the amount of chlorophyll in the elk scat, we can match that to the amount of chlorophyll in the grass. Thinking back to the earlier pictures, in the early spring the grass in the low elevation areas will have more chlorophyll than the grass at high elevations.
2010/photosynthesis/

14. Conducting elk scat transects
Today we are going to collect elk scat(jolly ranchers) using a transect method. You will set up the transects as a group and will be collecting different colors of jolly ranchers. The color corresponds to the timing of green up.
Jolly ranchers=elk scat
Pink= early greening grass
Blue= mid season greening grass
Purple=late season greening grass
Green= Agriculture
Will conduct a transect to count
total elk scat and the timing of greening
of grass that the elk are consuming at
6 different time periods

15. Directions:
1.) Assign a recorder, a counter , and a collector. 2.) Go to flag and record the date on the flag. 3.) Connect the two flags with the same date with the string. Make sure the string is in a straight line. 4.) Walk along the string, and count all the jolly ranchers that are within arms length from the center. 5.) Recorder should record the total number of each color of Jolly Rancher 6.) Count up the total number of each color and make a bar graph. 7.) Look at map and determine where the elk in your transect are eating.

16. This is a map of the timing of green up across the study area
This is a map of the timing of green up across the study area. Once you collect your data, you will look at the map to determine where you think elk are moving.

17. Discussion: How will climate change affect elk migration?
Have the students groups get together and show their bar graphs side by side. Discuss the differences in the dates. Ask the students what their guess would be about the available grass for elk at each date.
Then have the students start a discussion about how climate change may affect the elk.
1.) Imagine that climate change shifts everything earlier. What would happen to the elk?
2.) Imagine that there is no longer a purple (Late greening) category. What would happen to the elk?
3.) Imagine that the area is wetter with climate change, and all of the areas are greener longer. What would happen to the elk?
4.) If there was a period at the end of the summer where there was no green grass, what would you do as an elk?

18. Who cares about Phenology?
Who cares about this? Why would each of these groups of people care about phenology?
Ranchers? Elk? Researchers? Landowners? Tourists?