4.4 — Geographic analysis

Because habitat loss is the major threat for most species, effective protection requires detailed knowledge of a species' range, of the distribution of its potential and actual habitats, and of the exact delimitation of areas where it is protected. These geographic data are most effectively managed by Geographical Information Systems (GIS). Such systems allow a highly flexible visualisation of maps in different scales and projections (all the maps published in Annex II are generated with GIS software). In addition, there is a huge potential for further computer-aided analysis, for example:

• Comparison of maps from different sources and in different projections,
• Data quality control,
• Mapping the distribution of diversity hotspots,
• Calculation of range territories,
• Intersection with other GIS-layers such as ecoregions, land use or climate change,
• Geographic threat analysis.

The following chapter describes some of these applications, in particular for data quality control and mapping of migrant diversity. The basic concepts of GIS analysis have already been outlined in section 3.2, and the integration of results into the database is described in section 3.4. Users are encouraged to perform their own analyses, but need to keep in mind that the GROMS maps are at global scale. This means that zooming into maps reveals a considerable lack of acuity (for an enlightening discussion of scale problems, see Erasmus et al. 1999).

This document should be quoted as part of the publication "Riede, K. (2001): The Global Register of Migratory Species ­ Database, GIS Maps and Threat Analysis. Münster (Landwirtschaftsverlag), 400 pp." + CD

 by Klaus Riede