openModeller id: ENVSCORE
Current version: 0.1 Developer(s): Tim Sutton and Chris Yesson
Accepts Categorical Maps: no
Requires absence points: no
Author(s): Nix, H. A.
Implements a lax Bioclimatic Envelope Algorithm. For each given environmental variable the algorithm finds the minimum and maximum at all occurrence sites. During model projection, the probability of occurrences is determined as: p = layers within min-max threshold / number of layers Thus choosing a threshold of p=1 gives you the same model output as the original Bioclim model taking both the Suitable & Marginal classes as predicted presences. The Envelope Score algorithm is equivalent to the inclusive 'OR' implementation of Bioclim described in Pineiro et al (2007).
Nix, H.A. (1986) A biogeographic analysis of Australian elapid snakes. In: Atlas of Elapid Snakes of Australia. (Ed.) R. Longmore, pp. 4-15. Australian Flora and Fauna Series Number 7. Australian Government Publishing Service: Canberra. Piñeiro, R., Aguilar, J. F., Munt, D. D. & Feliner, G. N. (2007) Ecology matters: Atlantic-Mediterranean disjunction in the sand-dune shrub Armeria pungens (Plumbaginaceae). Molecular Ecology. 16, 2155-2171.
The following image shows a sample model in the environmental space (temperature x precipitation) generated with the standard dataset used for tests (Thalurania furcata boliviana localities dataset):
|fig. 1: Envelope score model for 2 variables.|