Hi, This is a question regarding technique rather than an R specific issue. I have been asked to evaluate a 30+ year long term continuous survey of bird presence/absence data that has an associated ocular estimate of the vegetation community percent coverage. The data are organized by subpopulations (5), and by year ( 1991 - present). We are interested in gaining understanding on whether bird presence is 1) related to vegetation community cover and 2) whether that relationship is variable over the period of record. Ultimately I can associate management to this, but that data has not be pulled together yet for this survey.
My first thought was to simply look to a clustering and nmds to examine which sites were more similar given the vegetation community. Following this I had intended to repeat that analysis using year as a grouping variable to see if the clusters change. This would then provide the basis for a trajectory analysis. Ok, so that might be rather very simple, I'm now considering a repeated measures approach, but do not have much experience here. Since every site is the same in all years, what changes is the bird count and perhaps the vegetation community coverage estimates. Can someone let me know if this alternate approach is a better approach and how to conduct the analysis in R? Thanks very much. If additional information is needed I can provide it, but I didn't want to fill mail boxes with unnecessary info at this time. Steve Steve Friedman Ph. D. Spatial Statistical Analyst Everglades and Dry Tortugas National Park 950 N Krome Ave (3rd Floor) Homestead, Florida 33034 steve_fried...@nps.gov Office (305) 224 - 4282 Fax (305) 224 - 4147 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
