maxlike-package: Model species distributions by estimating the probability of...

In maxlike: Model Species Distributions by Estimating the Probability of Occurrence Using Presence-Only Data

Model species distributions by estimating the probability of occurrence using presence-only data.

Description

A species' distribution can be characterized by the probability that it occurs at some location in space. Estimating occurrence probability can be easily accomplished using presence-absence data, but often researchers only have presence locations and environmental data for the study area. MAXENT is a popular software program for modeling species distributions, but it does not estimate the probability of occurrence. Rather, it returns various indices that are not easy to interpret (see Royle et al. 2012). Package "maxlike" provides a simple likelihood-based alternative.

Note

All presence-only models require a random sample of data from locations where the species is present. Unfortunately, random sampling is not a feature of most presence-only datasets, and bias in the estimated probability surface should be expected in such cases. This assumption can be greatly relaxed if one has presence-absence data, which will always contain more information about a species' distribution.

References

J. A. Royle, R. B. Chandler, C. Yackulic and J. D. Nichols. 2012. Likelihood analysis of species occurrence probability from presence-only data for modelling species distributions. Methods in Ecology and Evolution 3:545–554. doi: 10.1111/j.2041-210X.2011.00182.x.

See Also

maxlike, raster

maxlike documentation built on Sept. 18, 2023, 1:06 a.m.