Identify at least four factors which can affect the size of a wildlife population.
Method
Students become managers of a herd of animals in a paper-and-pencil and discussion-based activity.
Teacher Planning
Subjects: Mathematics, Science, Vocational Agriculture Skills: analysis, computation (calculating percentages),
evaluation Duration: one to two 45-minute periods Group size: any Setting: classroom Conceptual Framework Reference: l.C.3.. l.C,4., 1.0.,
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Background
Wildlife managers attempt to maintain healthy populations of wild animals, while factors-both avoidable and unavoidable-affect the populations. Some of these factors are loss of habitat, weather conditions, pollution of food and water sources, development of other natural resources, poaching, and recreation pressures. Many people are unaware of how such pressures can affect wildlife.
In the United States, it is the legal responsibility of state wildlife agencies to manage the wildlife populations within their respective states. It is the legal responsibility of the U.S. Fish and Wildlife Service, under the U.S. Department of the Interior, to govern some policies and programs affecting migratory species of animals (principally birds) and threatened or endangered species, as well as illegal importation and exportation of animals and animal products, illegal interstate transportation of all species, with additional responsibilities related to the overall well-being of U.S. wildlife.
Wildlife management is based on the best scientific and technical knowledge available. Such knowledge is growing; however, it is still limited, and is continually affected by changes in the complex relationships between wildlife, human beings, and their shared environments.
In a sense, everyone shares responsibility for wildlife management. Although there are legally responsible agencies, their work requires the thoughtful and informed cooperation of citizens. There are frequently differences of opinion about the most appropriate policies and programs affecting wildlife. Individual citizens, private conservation groups, private industry, community groups, and others all make important contributions to the overall conservation and protection of wildlife and its habitat.
The major purpose of this activity is for students hypothetically to assume the role of wildlife managers, and thus gain insight into some of the complex variables that influence stewardship of wildlife. This activity is not designed to provide a comprehensive understanding of all possible factors which can affect wildlife.
Activities
Each student is asked to be the manager of a moose (or other animal) population. The carrying capacity of the habitat is 100 animals. The point of the activity is to end up with a viable population after nine rounds, simulating nine years. If at any time the student's population reaches less than 10 or more than 200 individual animals, that student no longer has a viable "herd" and watches the other students until the conclusion of the activity.
Each student has a beginning population of 100 animals. The cards are separated into three decks of a total of 36 cards: a condition deck (18 cards), a reproduction deck (9 cards), and a management deck (9 cards). Shuffle the cards within each deck. Explain that cards will be drawn in the following sequence: condition card, reproduction card, condition card, management card. This sequence of draw will be repeated, each repetition representing an annual cycle (the students may think of each draw as representing a different season, e.g., autumn, winter, spring, summer). As each card is drawn, it is read aloud to the entire class. Each student then rolls his or her die and follows the instructions on the card to determine his or her herd population's new size. Some computations will result in fractions; numbers may be rounded to the nearest whole. NOTE: Students may object to the use of dice to determine the impact of decisions made for wildlife management purposes. Their concerns are appropriate; wildlife management is based on more than the chance elements reflected in the use of dice. However, chance has its impacts as well, as in the case of weather conditions in a given year. Encourage the students what is unrealistic, about the impact of dice in wildlife management is far more complex than can be represented through this activity.
Wrap up the activity with a class discussion. Include topics such as:
Identify and describe what appeared to be the impacts of the condition, reproduction, and management cards.
Given one of the objectives of this activity-to evaluate hypothetical management decisions-what seemed to be the benefits and/or liabilities, if any, of management decisions made?
Did populations "managed" under different strategies by different students show different trends? How do these compare? Would students "manage" differently if given a second chance?
What aspects of this activity seemed realistic? Which didn't?
What are examples of ways that habitat can be improved? Short term? Long term?
Is human management of wildlife populations necessary? Beneficial? Why or why not? For people? For the animals?
Variation
Add a monetary aspect to the activity. Students allowing hunting might have more available revenue for projects like habitat enhancement based on income from sale of hunting licenses. Other expenses might include salaries of wildlife managers, funds for research, feeding animals in severe conditions, relocation, etc.
Evaluation
Name four factors that can affect the size of a wildlife population.
Some wildlife managers have said that wildlife management involves more management of people than of wildlife. Explain what they might mean by the comment.
Instructions for Making Cards
Make the following cards, according to three categories: Reproduction Cards, Condition Cards, Management Cards. There are 36 cards in total. The number in parentheses indicates how many of each card are to be made. NOTE: The numbers of cards and the suggestions for numerical manipulations, e.g., three times the roll, are relatively arbitrary. they are designed for students to recognize that a number of diverse factors can affect wildlife; the numerical weights should not be interpreted literally.
As the cards are read aloud, be certain to note differences in decreasing or increasing herd size by percentage or by number.
(After using these cards once, students may want to experiment with making additional cards, or changing these cards. Students may also want to make additional complete sets of cards for use by small groups or individual students.)
NOTE CONCERNGIN REPRODUCTION CARDS: The rate of reproduction is designed to vary with population density. The method for determining your populations's rate of reproduction at a particular population size is derived from a number of assumptions. One of these is that carrying capacity is 100 individuals. As your population drops below 100, the potential rate of reproduction increases reaching a peak at just above 50 individuals. This effect mimics the potential for rapid population growth many herbivore populations can exhibit when population levels are well below carrying capacity; in other words, food resources are readily available for reproductive effort, given that other environmental factors prove favorable. Below 10 individuals, reproduction is not allowed, reflecting the severe reduction in reproductive activity observed at very low population levels because of, for example, imbalanced sex rations, the inability to find suitable mates, or the disruption of social and mating systems. As the population grows above 100 individuals, the reproduction rate steadily decreases, reflecting the increasing activity of limiting factors as the population exceeds carrying capacity.
Reproduction Cards
Reproduction Card - Excellent Year (3)
This has been an excellent reproduction year. Increase your heard by (100/your current population size) times five times your roll, if your current population is over 50 individuals. If your population is between 50 and 10, increase your population by the number equal to five times your roll. If your population is under ten, you may not reproduce.
Reproduction Card - Average Year (6)
This has been an average reproduction year. Increase your herd by (100/your current population size) times three times your roll, if your current population is over 50 individuals. If your population is between 50 and 10, increase your population by three times your roll. If your population is under 10, don't reproduce.
Condition Cards
Weather Card (2)
_____(Students need to specify what) has had a serious negative impact on the survival of the herd. Decrease your herd by the percentage equal to five times your roll.
Weather Card (2)
_____(Students need to specify what) has had a dramatic positive impact on the survival of the herd. Increase your herd by the percentage equal to five times your roll.
Habitat Destruction Card (2)
_____(Students need to specify what) has occurred, destroying critical habitat. Decrease herd size by the number five times your roll.
Predator Card (1)
Predation has occurred, affecting the herd size. Decrease herd size by the percentage equal to your roll.
Habitat Degradation Card (4)
_____(Students need to specify what) has occurred, damaging critical habitat. Decrease herd by the number equal to three times your roll.
Disease Card (1)
Disease has struck the her. Decrease herd by the percentage equal to your roll.
Habitat Loss Card (5)
_____(Students need to specify what) has resulted in a loss of critical habitat for the herd. Decrease herd by the number equal to five times your roll.
Poaching Card (1)
Poaching - illegal killing of animals - has reduced the size of the herd. Decrease herd by the number equal to two times your roll.
Management Cards
Habitat Restoration Card (1)
_____(Students need to specify what) has occurred, restoring critical habitat. Increase herd by the percentage equal to five times your roll.
Habitat Alteration Card (2)
_____(Students need to specify what) has occurred, altering critical habitat. Increase or decrease (students choose which before rolling the die) herd by the percentage equal to three times your roll.
Habitat Improvement Card (1)
_____(Students need to specify what) has occurred, improving critical habitat. Increase herd by five times your roll.
Research Card (1)
_____(Students need to specify what) research has been successfully accomplished. Increase or decrease (students choose which before rolling the die) herd by two times your roll.
Law Enforcement Card (1)
_____(Students need to specify what) law enforcement activities have protected the herd against illegal actions like poaching. Increase herd by the percentage equal to two times your roll.
Education Card (1)
_____(Students need to specify what) education activities have led to increased understanding of wildlife and habitat. Increase or decrease (students choose which before rolling the die) herd by the percentage equal to two times your roll, or by two times your roll.
Habitat Acquisition Card (1)
Habitat acquisition has increased the area of available and suitable habitat. Increase herd by five times your roll.
Hunting Card (1)
A request for a hunting season has been made. Do you wish to allow hunting in your area? If yes, decrease your herd by the percentage equal to five times your roll. If no, record no change in the size of your herd.
Wildlife managers attempt to maintain healthy populations of wild animals, while factors-both avoidable and unavoidable-affect the populations. Some of these factors are loss of habitat, weather conditions, pollution of food and water sources, development of other natural resources, poaching, and recreation pressures. Many people are unaware of how such pressures can affect wildlife.
In a sense, everyone shares responsibility for wildlife management. Although there are legally responsible agencies, their work requires the thoughtful and informed cooperation of citizens. There are frequently differences of opinion about the most appropriate policies and programs affecting wildlife. Individual citizens, private conservation groups, private industry, community groups, and others all make important contributions to the overall conservation and protection of wildlife and its habitat.
