1. Estimating Population size
Important in evaluating the health of ecosystem:
Is organism threatened or endangered….need protection? Wolves
Over-running habitat….
Should Population be thinned ? Deer

2. Count Individuals
Best for stationary organisms

4. Yosemite Transect

5. transect

6. Clumped distribution

7. Estimating population size by genotyping feces

8. Remote Cameras

9. Radio collars/ tracking devices

11. Mark and capture Method

12. Population Estimation
Basic Sampling Techniques
Tracking Snakes
Mark and recapture bees

14. Lincoln Index
ratio P N Entire Pop size recapture sample size
N R # marked # marked in recapture
P = (N1 x N2) R
P = total size of population
N1 = size of first sample (you will mark all & release)
N2 = size of second & subsequent samples (recapture: some will be marked, some won’t)
R = number of marked individuals recaptured in second sample = =

15. Estimating Population Size
MATERIALS: 50 beans, marking pen, plastic container with lid
PROCEDURE:
Mark 20 of the beans with the marker.
Place all 50 beans in the container and cover with the lid. Gently shake the container to mix the beans thoroughly. Take the lid off and without looking, withdraw 10 beans. Count the number of marked beans (R) and record in the data table.
Put the 10 beans back in the container and replace the lid. Shake the container again and withdraw a second set of beans. Again, record the number of marked beans in the sample in the data table. Continue in this manner until you have completed 10 trials.
Calculate the estimated population size for each trial using the Lincoln Index. When you have done this for all 10 trials, find the average by adding the estimates and dividing by 10.