Table 1. Mark-release-recapture data.
|
Turtle age (years) |
First visit # Marked & released |
Second visit Total Captured (marked and unmarked) |
Second visit Total recaptures (marked only) |
|
0 |
75 |
63 |
7 |
|
1 |
50 |
40 |
10 |
|
2 |
55 |
45 |
25 |
|
3 |
59 |
56 |
38 |
|
4 |
42 |
35 |
20 |
|
5 |
38 |
42 |
24 |
|
6 |
12 |
18 |
9 |
|
7 |
15 |
14 |
12 |
|
8 |
8 |
7 |
7 |
|
9 |
0 |
0 |
0 |
Question 1:
Based on these results (Table 1), what is the estimated number of individuals in the population in 2012 (round to the nearest whole number)? HINT: calculate the number of individuals in each cohort first.
a) 674 individuals
b) 1250 individuals
c) 745 individuals
d) 152 individuals
Table 2. Life-table for closely related species.
|
Age (x) |
Nx |
lx |
mx |
|
|
|
0 |
725 |
|
0.000 |
|
|
|
1 |
300 |
|
0.000 |
|
|
|
2 |
165 |
|
0.455 |
|
|
|
3 |
99 |
|
0.825 |
|
|
|
4 |
87 |
|
1.104 |
|
|
|
5 |
53 |
|
1.088 |
|
|
|
6 |
40 |
|
0.973 |
|
|
|
7 |
19 |
|
0.825 |
|
|
|
8 |
10 |
|
0.410 |
|
|
|
9 |
0 |
|
— |
|
|
Question 2:
By aIDing to the above life table (Table 2), what is the estimated net reproductive rate, R0, of this turtle species?
a) 0.51 individuals/individual
b) 10.5 individuals/individual
c) 0.77 individuals/individual
d) 1.41 individuals/individual
Question 3:
Using the life table (Table 2), what is the estimated generation time?
a) 1.08 years
b) 10.5 years
c) 3.9 years
d) 4.8 years
Question 4:
In another closely related species of turtle (general reproductive dynamics are the same as the first two turtle species in question 1 and questions 2 & 3), we find that the value for the net reproductive rate (R0) is 0.95 and the generation time is 2.5 years. Solving for l or r as you think appropriate, what is the per capita rate of growth for this population?
a) 0.02 individuals/individual/year
b) -0.35 individuals/individual/year
c) 0.51 individuals/individual/year
d) -0.02 individuals/individual/year
Question 5:
You also compute the per capita rate of growth of the population represented by Table 2, and obtain a value of -0.173 individuals/individual/year. Based on this value, which of the following describes this population?
a) growing
b) declining
c) stable
d) none of the above
Question 6:
Given the total population size of the population in Table 2 (in year 2012), using the per capita growth rate in question 5, and assuming that this growth rate does not change, what is the expected population size of these turtles in year 2022?
a) 474 individuals
b) 230 individuals
c) 4730 individuals
d) 0 individuals
