GROMS - Global Register of Migratory Species

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Because migratory species cross borders, their efficient protection requires international cooperation. Endangered migrants are protected by the Convention on the Conservation of Migratory Species of Wild Animals (also known as CMS or the Bonn Convention), an international treaty bringing together 74 member states (1. June 2001). However, knowledge about animal migration is insufficient and widely scattered. The Global Register of Migratory Species (GROMS) supports the Bonn Convention by summarising the present state of knowledge in a relational database connected to a geographical information system.

The database provides fully referenced basic information on migratory species, GIS maps, and a bibliography. Because of considerable differences in migration behaviour between populations of a single species, populations form the basic entity of the GROMS data model. ‘Populations’ are either defined taxonomically (subspecies) or geographically. A list of 2880 migratory vertebrate species is published here. It contains scientific names with authority and synonyms, vernacular names (English, French, German, Spanish), protection status by listing under CMS and its agreements, threat status according to international red list categories, and CITES appendices. Long-distance migrants and possible migrants are marked up. Bird migrations are comparatively well monitored, but for mammals, fishes and insects sufficient information is only available for economically important species. Considerable knowledge gaps persist for bats, Asian antelopes, small whales, tropical fishes and insects.

The Bonn Convention lists endangered migratory species in its Appendix I, thereby obliging member states to conserve these species by protection and habitat conservation. Appendix II lists species with an unfavourable conservation status, encouraging parties to conclude special agreements, which should benefit the species. An analysis of threat status according to the "International Red List 2000" allowed the identification of threatened migrants not yet listed by CMS, and a corresponding extension of the CMS appendices is proposed. In addition, fish migrations within tropical river systems need to be studied, as there are considerable gaps in knowledge and severe threats by river dam construction in tropical and subtropical rivers.

For 545 species, distribution maps on a global scale were digitised within a geographical information system (GIS), together with point data on aggregation areas for Eurasian ducks and geese. This set of maps makes it possible to provide answers to the seemingly simple query for species occurring within a certain area. A JAVA-based graphical user interface (GUI) has been designed for user-friendly visualisation of interactive maps. This interface connects the GIS maps with the database and allows searching for species within an area or generation of species reports. A web-based version of this tool can be tested at

Maps for 78 (mainly Appendix I) species are printed here, together with species accounts. As an example of analysis using other GIS data sets, distribution maps were intersected with administrative borders of geopolitical units. This operation generates range state lists for each species, and species lists for each country, both of which were re-imported into the database. A calculation of migratory species numbers for each administrative unit reveals that diversity does not increase towards the tropics, but is high in temperate regions. Therefore, the present concentration of biodiversity conservation plans within tropical ‘hotspot areas’ will be insufficient for the conservation of most migratory species: much of the responsibility for conservation of migrants falls into the range of industrialised nations and transformation countries within higher latitudes.

Further possible applications of GIS analysis consist in identification of potential threats by changes in land use and development, pollution hazards, habitat degradation and the effects of ‘global change’. A first pilot analysis identified the following major threats:

  1. Large populations are essential to provide the necessary genetic diversity for adaptation to a changing environment, and to minimise the risk of climatically induced extinction of entire populations.
  2. Hunting and taking must be reduced, as their effect will be more severe on weakened or concentrating populations. Over-exploitation in fisheries has to be stopped, to maintain sufficient resources for seabirds and marine mammals.
  3. Maintenance of entire species ranges and potential habitats is necessary to allow for adaptive changes in migration patterns.


This document is part of the publication: "Riede, K. (2001): Global Register of Migratory Species. Weltregister wandernder Tierarten. Münster (Landwirtschaftsverlag), 400 pp." + CD (see copyright)