Range & Diversity

Range and Diversity Modeling with Lifemapper (LmRAD)

The Lifemapper team is currently working to achieve two objectives with their Range and Diversity Modeling: first, to support Macro-Ecological modeling; and second, to integrate different scientific disciplines.

Studying biodiversity patterns includes describing, visualizing and analyzing different aspects of the numbers and abundances of taxa in both time and space. This can be done at multiple scales, looking at different resolutions of time, space, and even different levels of organism classification, like phylogenetic or taxonomic attributes.  Biodiversity patterns can be explained by species distributions and abundance.  These patterns are critical information for conservation and land management decisions.

A simple Range and Diversity experiment could consist of several general steps.  First, choose a region of interest.  Macro-ecological studies often start with continents or even the entire world.  Second, choose a set of organisms to study.  Researchers may choose species by taxonomy, phylogeny, or other attributes, such as ecological, like predator/prey relationships or physical attributes, like body size.  Organism data can come from any data source, it can be past, present or future, as well as predicted or observed.  Third, intersect each organism layer with a grid for the chosen geographic region to create a matrix where each cell contains a value for presence or absence of each species in the experiment.  This structure is known as a Presence Absence Matrix, or PAM.  Fourth, compute indices, by-site, and by-species calculations.  Finally, randomize the PAM, and re-compute indices and calculations to determine the statistical significance of the results.

There are major challenges related to study biodiversity patterns at large extents, high resolutions, and with thousands of species.  Lifemapper addresses these challenges by providing web services for assembling and analyzing many species distribution layers at multiple resolutions over arbitrary geographical extents.   These web services can be accessed programmatically and through the Lifemapper web app in the future.