dear Nick, I do not know your data, however it seems to me that the pattern of relative abundance of salamanders should not exhibit a sudden change, but rather a gradual change.
If this is the case, have a look to the segmented package and references therin. In particular have a look to the relevant Rnews paper Segmented: an R package to fit regression models with broken-line relationships. R News, 8, 1: 20-25 at http://cran.r-project.org/doc/Rnews/Rnews_2008-1.pdf Hope this helps you, best, vito On Tue, 16 Nov 2010 17:30:49 -0500, Nicholas M. Caruso wrote > I am trying to understand my population abundance data and am looking into > analyses of change point to try and determine, at approximately what point > do populations begin to change (either decline or increasing). > > Can anyone offer suggestions on ways to go about this? > > I have looked into bcp and strucchange packages but am not completely > convinced that these are appropriate for my data. > > Here is an example of what type of data I have > Year of survey (continuous variable) 1960 - 2009 (there are gaps in the > surveys (e.g., there were no surveys from 2002-2004) > Relative abundance of salamanders during the survey periods > > Thanks for your help, Nick > > -- > Nicholas M Caruso > Graduate Student > CLFS-Biology > 4219 Biology-Psychology Building > University of Maryland, College Park, MD 20742-5815 > > ------------------------------------------------------------------ > I learned something of myself in the woods today, > and walked out pleased for having made the acquaintance. > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. -- Open WebMail Project (http://openwebmail.org) ______________________________________________ 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.
