- How accurately did your group estimate the population size in PART A?
Hopefully within ballpark.
- Explain why the mark and recapture method is an important tool for the wildlife biologist.
We can use this method to answer several questions:
Is the population approaching carrying capacity (or perhaps over-populated?)
Is the population declining and the species should be protected?
Is an endangered species recovering?
- Should only one person have performed the ten sampling trials or is it alright to rotate this duty within your groups?
If the procedure is described properly, different individuals should be able to repeat the sampling, and avoid any bias a given individual may make in setting traps.
- p. 148 Suppose a farmer clipped the toes of 88 mice in his field. Two weeks later the farmer trapped and caught 54 unmarked and 9 marked field mice. Calculate a population estimate for the mice in his field. Do you think the farmer should buy a cat?
N = Tn/t (n = marked + unmarked)
N = 88 * (54+9) / 9
N = 88 * 63 / 9
N = 88 * 7
N = 616
Time to buy a cat?
- A wildlife biologist wanted to estimate the size of a deer population because farmers were complaining that the deer were destroying their crops. She trapped and tagged the ears of 28 deer in June. In August she trapped a total of 60 deer and 17 of these had tagged ears. How large was the deer population in that area? The carrying capacity is 95, Should any hunting permits be issued? If so, how many?
N = Tn/t
N = 28 * 60 / 17
N = 1680 / 17
N = 98.8 = 99
If carrying capacity is 95, can issue 4 hunting permits to reduce the number to 100% carrying capacity.
- Skip question on mealworms.
- Using Tables 3 and 4, do the original T or n seem to play a role in the accuracy of the population estimate for the group? Give some examples from the data and explain.
Assuming capture rate is random, the larger the T (original captured) and n (recaptured), the less your estimate is affected by random events.
