WLF 448: Fish & Wildlife Population Ecology

Lab Notes 5, Fall 2008

Lab Notes 5, Fall 2008

As part of your new job as a research technician, you helped collect data on the
population response of deer mice (*Peromyscus maniculatus*) to grazing. A pilot study
was conducted in the Curlew Valley of southeastern Idaho. Mark-recapture was used to
estimate the abundance of deer mice in 9 small isolated fields (3 with no grazing, 3 with
moderate grazing, and 3 with high-intensity grazing). A trapping grid consisting of 70
live traps, spaced 15 m apart, and covering 0.81 ha was established in each field.
Trapping was conducted for 10 consecutive nights (per field). As part of the ** preliminary
data analysis**, your boss has asked you to analyze data from

How many individual animals were captured? (1pt)

How many animals were captured more than once? (1pt)

What percent of the animals caught on the fourth night were new captures (first time captures) (1pt)

What was the mean of the maximum distance (in meters) between capture points for all deer mice captured 4 times? (hint: look at the summary tables in your output, assuming you selected "Summary" in 2Capture). Why might this number increase for animals caught more frequently (i.e., explain the increase in the mean maximum difference between 2, 3, 4, 5, and 6 captures)? (2pts)

Which model did you use to estimate abundance? Explain this model in your own words (assumptions of the model). (2pts)

Is the population closed?

**Justify your answer**. (2pts)What is the estimated probability of

**capture**under the*appropriate*model? What is the estimated probability of**recapture**under the same model? What does a higher probability of recapture imply? (3pts)What is the estimated population size under the

*appropriate*model? What is the*approximate*95% confidence interval for this estimate? (2pts)Do you consider this a good estimate of

*Peromyscus*abundance in the sample you analyzed?**Why or why not?**(Hint: consider the precision of the estimate, robustness of the model selected, and probability of capture given N<100). (3pts)

CAPTURE input and output files. = 3pts.

Hardcopy of your input file.

Hardcopy of your output file(s).

**Note:**you can call the output file into a wordprocessor, "clean up" the output, and then print the applicable portions. If you take this approach, select a small Courier font to keep numbers aligned.Answers to the questions.

**Note:**please include the question or a shortened version of the question with your answer. Also, answers should be typed and*double spaced*.

Problem sets are due at the beginning of lab the following week
- if they are not turned in at that time, we will deduct 2 points per day up to a maximum
of 1/2 the total available points. THERE WILL BE NO EXCEPTIONS TO THIS RULE!!!!! |

* Revised:* 30 September 2008