Modeling Species Distribution with GIS - Research Techniques in Animal Ecology - page 397

Figure 11.1 Percentage of the papers dealing with habitat modeling using no spatial information,
RS , GIS , and a combination of RS and GIS for three periods (1980-1985, 1986-1991, and 1992-1996).
according to the available layers. The combination of these layers and the sub-
sequent identification of the areas that meet the species' requirements identify
the species' distribution range, either actual (if there is evidence of presence) or
potential (if the species has never been observed in that area).
This basic scheme can be implemented using different approaches. A few
classifications based on different criteria have been attempted. For example,
Stoms et al. (1992) classified models based on the conceptual method used to
define the species-environment relationship, whereas Norton and Possingham
(1993) based their classification on the result of the model and its applicabil-
ity for conservation. Accordingly, Stoms et al. (1992) classified GIS species dis-
tribution models into two main groups—deductive and inductive—whereas
Norton and Possingham (1993) gave a more extensive categorization of mod-
eling approaches.
We have tried to define logical frameworks that can be used to classify
species distribution models based on the major steps that must be followed to
build them. To this end, we find the deductive-inductive categorization the
most suitable starting point because it focuses attention on the definition of
the species-environment relationship, which is the key point for the imple-
mentation of distribution models.