Assignment
Do the calculations, graphs,
Hint
some of conse;1721= true class population size.
PA+R=
N=M c/R=150 150/17 sum of the class data 17 marked/115
N class =1323
Density 19.67+28+9=18.89 beans/25m^2
104 area total 820m^2
EST=520
Answer these questions
Questions to answer (due next Friday)
1. Provide your data as tables, including the raw data, calculated estimate of population size, and upper and lower 95% confidence intervals. Also report your results in a single figure for all estimates (bar chart with 95% confidence intervals for all estimates, i.e. your group data and the entire class data for each of the two methods of estimating population size).
2. Why are indices not useful for estimating population sizes, but only for relative comparisons?
3. Evaluate your estimated population sizes in comparison to the actual population size. Which method of estimation was more accurate? What assumptions, if any, were violated for each method? How could you improve your estimate?
4. Why do ecologists estimate population size? When would an ecologist want to use a density estimate versus a mark-recapture estimate? (Think about organisms, habitats, types of questions...)
5. What would happen to your density estimate if:
a. the area observed was 50% smaller?
b. some individuals (e.g., females) were harder to detect?
c. individuals were attracted to sampling areas?
d. sampling areas were not randomly located?
Provide mathematical explanations for why each would occur, making sure to think about both estimates and confidence intervals.
6. What would happen to your mark-recapture estimate if:
a. several of the animals died or migrated out of the area between captures?
b. the marks were not properly observed?
c. handling the animals killed them after you had released it back into the wild?
d. some individuals had a higher probability of being caught than other individuals?
Provide mathematical explanations for why each would occur, making sure to think about both estimates and confidence intervals.
Follow the guideline.