Migration and Range Change Estimation in R

A set of tools for likelihood-based estimation, model selection and testing of two- and three-range shift and migration models for animal movement data as described in Gurarie et al. (2017) . Provided movement data (X, Y and Time), including irregularly sampled data, functions estimate the time, duration and location of one or two range shifts, as well as the ranging area and auto-correlation structure of the movement. Tests assess, for example, whether the shift was "significant", and whether a two-shift migration was a true return migration.

marcher

Migration and Range Change Estimation in R (Development version)

UPDATE 2020.04.27: Github version has been updated to iron out some more issues, including an error in the range-shift testing function.

Install via:

require(devtools)
install_github("EliGurarie/marcher", build_vignettes = TRUE)

UPDATE 2019.10.04: Github version has been updated to iron out some issues (especially with plotting).

UPDATE 2017.04.12: A stable version of marcher is now on CRAN at https://cran.r-project.org/web/packages/marcher/index.html

The marcher package provides functions and tools for mechanistic range shift analysis decribed in Gurarie et al. (2017). 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.

References

Gurarie, E., Francesca, C., Peters, W., Fleming, C., Calabrese, J., Müller, T., & Fagan, W. (2017) Whether, whither, when, and will it return? A framework for modeling animal range shifts and migrations. Journal of Animal Ecology, 86(4):943-59.