Lesson Nine: Population Problems

FWClogoSmallBefore European settlement, Florida had an estimated black bear population of 11,000 and an estimated human population of 350,000. Today, at least 4,000 Florida black bears share the state with over 20 million people. As discussed in the previous lessons, one of the primary factors threatening the continued success of the Florida black bear is habitat loss. As more and more land is cleared to make room for shopping malls, homes, schools, roads, and other facilities for Florida’s steadily growing human population, less and less undisturbed, natural habitat is left for bears to inhabit.

Photo courtesy of Mark Stevens

Courtesy of Mark Stevens

And unfortunately, most of the natural habitat that still remains is criss-crossed with a network of roads. In addition to directly causing the death of bears as a result of collisions with vehicles, roads traversing black bear habitats also indirectly impact bear populations by isolating individuals from food sources, shelter, and potential mates.

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In this Lesson 9 Population Problems, students will construct line graphs illustrating human population growth and Florida black bear roadkills and learn how to interpret the graphs.  They will also create bar graphs of monthly black bear roadkill, interpret the results, and discuss seasonal variation in road mortality.

Biologists at the Florida Fish and Wildlife Conservation Commission have been collecting information on and keeping records of the number of black bears killed on Florida roads for more than 30 years. The data indicate black bear mortality due to vehicle collisions is increasing. In fact, today, roads are considered the leading direct cause of Florida black bear mortality. As the population of people in the state increases, the number and size of roads and the number of vehicles on these roads also increases. Many major roads and highways, like Alligator Alley in south Florida, US 19/98 in the Panhandle, and State Road 40 in north-central Florida, are arteries connecting large urban centers and they cut directly across black bear habitat.

Lesson 9-2The number of bears killed on Florida’s roads has remained above 200 bears each year since 2012. Vehicles killed a total of 231 black bears in 2016. With the total population of black bears in the state at about 4,000, that means that in the year 2016, 5.7 percent of the total black bear population was killed on Florida roads and highways.

Lesson Summary:

Key Question: How does the growth of Florida’s human population affect bear populations?

Main Topic: Impact of human population growth on Florida black bear mortality rates, especially due to road kills

Format: Math and graphing activity

Description: Students interpret data tables and construct line graphs illustrating the relationship between human population growth and road kills of Florida black bears over time.  They also construct bar graphs to investigate seasonal differences in male and female Florida black bear road kills.

Common Core Standards: Coming Soon

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