I'm looking for a resource for analyzing some wildlife population cycle data other than Royama 1992. I get how to do run the Auto-regressive models with a perfect data set, but I am looking for something that gives more discussion to dealing with more realistic data sets containing missing values, trend, etc. Any suggestions? I'm hoping there is something akin to Paul Allison's regression SAS guides (not because of SAS, but because it's practical) for time series analysis, but I haven't found one yet.
Specifically, I want to be able to use periodograms or spectral density to determine if there is even a cycle and then use auto-regression to model density dependence and density independent effects. The data set is messy and I really need something that walks through potential solutions to cleaning up the data and what the pitfalls are.
Hi Timothy, have you considered a state space model (cf. Humbert, J.-Y et al., 2009. A better way to estimate population trends. Oikos 118, 1940-1946)? The performance tends to remain high even with a lot of gaps missing in the time series. Cheers, Matt
Hi Timothy,
If you send me your sample data in DOS (.txt) or Statistica format, I will try to do something with it.
Take a look at the Lomb-Scargle Algorithm which is capable of estimating the periodogram/spectral density of unevenly sampled data. I've used this in a few applications and its quite robust at picking out periodic components in noisy and sparsely sampled data. You can find the reading in the attached link - and there are a variety of software packages that use this algorithm
http://www.aip.de/groups/soe/local/numres/bookfpdf/f13-8.pdf
Hi Timothy!!
I just worked following Berryman and Turchin´s criteria (2001).http://www.jstor.org/stable/3547231?seq=1#page_scan_tab_contents
you can use R to perform your time series analysis. You can follow my time series analysis too. http://www.jclmm.com/qk/20141/1.pdf
Kind Regards and Best wishes
David, thanks for the L-S suggestion. It seems like the superior method and it even has an R package!
- Badges
- Science method
- Similar topics
- Biological Science
- Ecology