Migration and Range Change Estimation in R
The marcher package provides functions and tools for
mechanistic range shift analysis decribed in Gurarie et al. (in
press). The methods are designed to estimate parameters of range
shifting, including coordinates of the centroids of (2 or 3) ranges, the
times of initiation and duration of each shift, ranging areas and time
scales of location and velocity autocorrelation. Because the estimates
are likelihood based, there are several handy inferential tools
including confidence intervals around all estimates and a sequence of
hypothesis tests, including: (a.) What is the appropriate (highest)
level of autocorrelation in the data? (b.) Is an estimated range shift
significant? (c.) Is there a stop-over during the migration? (d.) Is a
return migration a strict return migration?
The vignette introduces the family of range shift models and illustrates methods to simulate, visualize, estimate and conduct the hypothesis tests.
Gurarie, E., Francesca, C., Peters, W., Fleming, C., Calabrese, J., Müller, T., & Fagan, W. (in press) A framework for modeling range shifts and migrations: Asking whether, whither, when, and will it return. Journal of Animal Ecology.