Student Stella Modeling Project

The Black Bear Population In Maryland.

Should there be a hunting season?

• Unit Purpose
• Unit Objective
• Unit Overview
• Materials
• General Considerations
• General Facts about Maryland Black Bears
• Bear Model 1956-1996
• Bear Model 1996-2036 with hunting
• Conclusions

Unit Purpose

Introduce the concept of modeling and the use of modeling software to students in a Computer Programming II course using a topic of local interest to our rural students/community. Provide cross-curricular instruction opportunities. Illustrate the "dynamic" nature of populations and other systems. Encourage the objective study of an emotionally charged issue. Enable students to have an actual impact on local policy decisions. Expose students to "how science is done".

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Unit Objective

The number of incidents of crop and livestock damage due to bears has been increasing. Legislation has been proposed to create a fund of money to reimburse farmers for damages due to bears. A hunting season has been proposed as a solution to the problem. We had two main objectives:

1. Create as realistic a model of the bear population as current information would allow.
2. Based on that model, would a hunting season be a viable option and, if so, what would be the optimal quota of bear.

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Unit Overview

Students used various resources to research the black bear in Maryland. The resources included various web sites on the internet, local park ranger knowledgeable about area bears, State Department of Natural Resources "Bear Expert", Frostburg State University Wildlife professor, high school science teachers and Project WILD. The information was discussed in class. Each student created their own Stella model of the black bear population. Students then critiqued the various models and the class collaboratively created one group model.

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Materials

STELLA (modeling software), Netscape (World Wide Web) and the above human resources.

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General Considerations

While there has been an effort to collar and track black bears in the state, a surprising amount of information is based on estimates or is unknown. Where information was not available, we've made every attempt to make an informed, rational choice in our information. In order to determine if a hunting season was viable, we first had to come up with a model that would realistically portray the current bear population. We created two models, 1 for the bear population starting in 1956-1996 in which we achieved the current estimated population. We then took the numbers based upon that model and used them in our model for the hunting question. It is also based on a 40 year range, 1996-2036.

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General Facts about Maryland Black Bears

• In 1956 there were only approximately 12 bears in the state!
• In 1991 (the year when the last count was done) the population was estimated at between 165-200. The number being used most often in 1995 was 200.
• The majority of Maryland Bears now live from Cumberland, west.
• Some bears make their way to other parts of Maryland from other states. When these bears are captured, they are brought to Western Maryland. They amount to only about 1 bear every 2 or 3 years.
• Bears have large territories and will migrate/immigrate from/to the "state"
• There has never been a direct restocking program in the state of Maryland. However, in the late 70's, Pennsylvania stocked areas of south western Pennsylvania and many of these bears immigrated to Western Maryland. In the mid-80's, West Virginia modified its hunting law so that there was more pressure on male bears and less on females. This increased the number of bears in the state some of whom made their way into Western Maryland.
• Bears average about 3 per litter.
• Females breed around 3 years of age though about 10% or less breed at 2 years of age. The bears who breed at 3 give birth to their cubs when they are 4 years old, the others give birth when they are 3 year of age.
• There is a two year period between litters ... unless the female loses all of the litter in which case that same female will breed the following year (not wait two). The loss of a whole litter happens about 1 out of every 7 or 8 litters
• The ratio of male to female is actually a little skewed to males approximately 60-40.
• Less than 10 percent of mature bears die each year. This is generally not due to disease but to vehicles and illegal poaching.
• There is a 50 percent mortality for first year bears.
• By the time cubs reach maturity, here is approximately a 70% mortality rate
• Of tagged bears recovered last year (dead), 19 were recovered out of state, 11 were recovered in state. An indication that the habitat will not support more bears will be if there is an increase of tagged bears that are recovered outside the state - especially females whose range is less that of males. This suggests the area is near (or perhaps beyond) the saturation point for the optimal bear population.

Conclusions

The estimated 200 bears living in Maryland seem to be an adequate stock for a viable bear population. Using 200 as a target population size, we have found that a hunting season which culls 10 or so mature black bear per year would not adversely impact the survivability of the population. Having said that, we must point out that no provision has been made in the current model for habitat stress from other states nor from the effect of increasing encroachment of humans into the bear territories (such as increased bear/human contact and decrease in food supply).