1. Power analysis for a Mark recapture project Dan Bachen Department of Ecology Montana State University

2. Project overview Data collection –Blacktail WMA –24 plots –4 weeks

3. Mark Recapture Data collection Methods –Trap grids 8x8 –Sherman live traps –5 nights per plot –Unique marks 4 species –Deer mouse dominant > 90% of captures

4. Data example Site Capture Location N1 Capture Location N2 Capture Location N3 Capture Location N4 Capture Location N5 SC104G000 SC104E000 SC106F4G00

5. Power analysis Goals –Optimize sample size Treatment effect -.1 to -1 20 sites used (10 treatment, 10 control) 40 sites used (20 treatment, 20 control) –Effect of -.84 recorded by Ostoja 2009 Assumptions –Abundance estimates normal –Capture probability.2 un-captured individuals.9 captured individuals

6. Power analysis Methods –Generate abundances using likelihood analysis (Rcapture) –Quantify statistics –Use statistics to set parameters –Iterate experiment –Score success

7. Results Mean: 7.44 SE: 5.84

8. Results

10. Discussion Experiment might have worked Did I use the right tools? –No –Aggregation of samples Example: –Abundance= 158.2 –SE= 2.3

11. Future Work Re-run power analysis aggregating samples –New tools –RMark Compare results to other techniques