A DesktopGARP distribution map.

GARP (Genetic Algorithm for Rule-set Production) is an algorithm developed by David Stockwell that determines characteristics of a species native habitat based on environmental data observed at known collection points. A GARP analysis looks for similarities in the environmental profiles of the collection locations and forms conclusions about the range of the species based on factors such as temperature, precipitation, elevation, and soil type.

DesktopGarp brings the power of the GARP algorithm to BRC’s suite of habitat analysis tools. DiGIR and Species Analyst search multiple collection databases to create an occurrence map—a map locating where all specimens of a given species were found. DesktopGarp then merges this specimen information with environmental data to produce a distribution map—a map showing the geographical areas the species is most likely to inhabit.

Scientists can use DesktopGarp to:

• study the species range as it is now;

• estimate the range the species might have occupied in the past;

• model how changes to the environment (such as a change to the average temperature) might affect the species range;

• investigate how an ecosystem might react to the introduction of a foreign species.

A GARP analysis is computationally intensive. BRC’s Lifemapper distributes the computational load by letting Internet users around the world participate in creating GARP niche models.