R: Model species distributions by estimating the probability of...
maxlike-package
R Documentation
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.
Details
Package:
maxlike
Type:
Package
Version:
0.1-5
Date:
2013-12-17
License:
GPL (>=3)
LazyLoad:
yes
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.