ISLE ROYALE WOLF MOOSE STUDY

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1 ISLE ROYALE WOLF MOOSE STUDY I can explain how and why communities of living organisms change over time. The wolves, the moose, and their interactions have been studied continuously and intensively since This is the longest study of any predator-prey ecosystem in the world. THE LOCATION Isle Royale is located in the northwest portion of Lake Superior. It is ~50 miles long and ~8 miles wide. Isle Royale is home to a population of wolves and moose. These wolves are the sole predator of the moose, and moose represent ~90% of the wolves diet. THE WOLVES Wolves first came to Isle Royale in about the year They arrived by walking on an ice bridge from Canada. In a typical year, Isle Royale has ~24 wolves living in three packs. The challenge in a wolf s life is to get enough food to survive another season. The food they eat - moose - is dangerous to kill and not always plentiful.

2 THE MOOSE Moose first came to Isle Royale in about the year They probably swam to Isle Royale. In a typical year, Isle Royale has ~1000 moose. Except for the close bond between cow and calf, moose live solitary lives. During the summer moose eat enormous amounts of food (~40 lbs per day). They feed on the leaves of dozens of herbs, ferns, shrubs and trees. During the summer a moose will increase its body weight by ~25%. All of this weight is lost each winter. THE STUDY Every summer researchers spend time on Isle Royale. They observe moose forage, assess the impact of moose ticks, perform necropsies on moose carcasses, measure vegetation upon which moose depend, collect wolf scat (for DNA) and moose scat (for diet analysis). Every winter from mid-january to early-march, they count the number of wolves and moose on Isle Royale. They also estimate rates at which wolves kill moose and perform necropsies on wolf-killed moose. Most of these observations are made from a small aircraft that lands on a frozen harbor on the shores of Isle Royale.

3 WHAT HAS BEEN LEARNED ABOUT THE RELATIONSHIP BETWEEN THE MOOSE & WOLVES? While the summer diet of moose is diverse and relatively rich, the winter diet is not. During winter, balsam fir comprises 30-60% of a moose s diet. Balsam fir is not very nutritious, but is it relatively abundant - so moose eat it. Because balsam fir is such an important part of a moose s winter diet, the moose and forest are connected importantly through balsam fir. Isle Royale s wolves and moose have been valuable for informing us about the limits of our ability to predict and understand natural systems, the nature of predation, and many particulars about why and how wolves and moose are the way they are. Wolves, moose, Isle Royale... they represent an intricate, dynamic, interconnected set of relationships. Observing that which is beautiful inspires wonderment and respect.

4 Isle Royale Moose Wolf Assignment Data I can explain how and why communities of living organisms change over time. Below is a data table that shows the estimated population numbers of moose, wolves, and balsam fir trees on Isle Royale from 1960 to Your job is to use the data to create a line graph that shows the relationship between these organisms. Each organism must be charted on the line graph with a different color. When you finish creating the graph, you must answer the questions that follow. Isle Royale Moose Population Study Data Year Wolf Population Moose Population (Estimated)

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6 Analysis and Conclusion of the Study Data Answer the following questions in COMPLETE SENTENCES and turn in with the rest of your packet when you finish your work. 1. In what year did the wolf population peak? 2. As the moose population rises, what happens to the wolf population? 3. What do you think might have happened to the wolf population in the 1980s? 4. What long-term effects could a large moose die-off have on the wolf population? 5. What will happened to the ecosystem if the moose population becomes too numerous? 6. What could happen to the ecosystem if the wolf number rose drastically?

7 7. How many wolves do you predict will be living on Isle Royale 5 years from now? Explain. 8. Consider if the wolf numbers continue to decline so the population eventually becomes extinct on the island. If this occurs, do you think wolves should be reintroduced into the Isle Royale ecosystem? Explain.