GROMS - Global Register of Migratory Species

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It has become common practice that scientists complain about insufficient data sets, and a claim for "further studies" forms an important part of every species action plan or grant application. The GROMS has demonstrated that indeed there are surprising knowledge gaps. But there is also an overwhelming amount of detailed studies available for certain areas, providing counts and distribution data at a high spatial resolution (e.g. Hammond et al. 1995). Most of the results are stored on paper or scattered digital resources, not amenable to interactive searching. Therefore, a transformation of these results into adequate environmental policies requires time and access to good libraries. The present project hopefully will remedy this situation at least partially: It is now possible to search geographically for a subset of migratory species, and the resulting information could serve as a starting point for decision makers to identify threatened species groups, and to consult the respective experts.
This chapter outlines recommendations and perspectives for an improvement of data exchange and accessibility, and presents a condensed threat analysis for conservation policies, based on the author’s personal experience gained during this project.

Biodiversity informatics lessons from the GROMS project

The GROMS is not an isolated database. Because migration is observed in a wide variety of species, distinct information sources had to be evaluated, ranging from species databases to GIS datasets. The experiences gained during this process of data integration might be useful for the ongoing process of harmonising biodiversity informatics initiatives (see chapter 2, for an outline of the most important initiatives). For fishes, future data exchange between both databases is facilitated by a direct hyperlink, which allows switching from GROMS to Fishbase on the World Wide Web. For the IUCN Red List 2000 in its digital format (Hilton-Taylor 2000), the IUCN species code has been stored within the GROMS, to facilitate future compatibility. In the future, similar connections could be made to other species databases. But up to now there is no comprehensive database available for any of the other animal groups covered by the GROMS. This would be particularly necessary for birds, where considerable nomenclature differences complicated data exchange with a variety of sources, requiring management of synonyms and parallel taxonomies. Given the huge number of ornithologists, and the comparatively low number of unknown species, it is strange that there is still no "Birdbase" available. New taxonomic database initiatives such as the "Global Biodiversity Information Facility" ( will hopefully speed up computer access to taxonomic information, and develop protocols for interoperability of databases.

Taxonomic problems were even worse on the level of subspecies, where the GROMS seems to provide the first digitally available subspecies list of migratory non-passerine birds and marine mammals. This list has to be extended for passerine birds and all other mammals, but hopefully in cooperation with other taxonomic database initiatives. A higher taxonomic resolution is necessary for an adequate assessment of migration behaviour, which differs between populations. In addition, improved genetic studies will lead us to a better understanding of migratory pathways of populations, and conservation plans will have to take into account the results from such high-resolution studies. In summary, maintenance of migrant diversity requires conservation of all subspecies and populations. But subspecies and populations are often subjects of scientific controversy, and a satisfying solution of the "population problem" is still a challenge for biodiversity information systems, requiring complex data models. In addition, an efficient management of population data requires links to museum specimen databases and gene banks.

The greatest challenge for the GROMS was the integration of geographic information. The GIS format allows efficient data exchange, either for export or for import of other distribution maps. The GROMS imported distribution maps for African terrestrial mammals (Institute of Applied Ecology 1998), and exchanged waterbird maps in GIS format with UNEP-WCMC without problems. The difficulty here was GIS data administration, retrieval and visualisation. This required the design of a geodatabase, together with a web interface for visualisation, which is compatible with OpenGIS standards (see chapter 3, and Riede 2001). This should provide the necessary link to environmental datasets from other disciplines (agriculture, forestry, planning agencies) and organisations, including governments and private sector. However, lack of integration between such spatial environmental data sets is comparable or even worse than in biology: "Environmental impact studies for [...] development
projects are completed without access to an integrated database [...]. Large-scale environmental inventories are unable to incorporate local findings. All of this leads to a need for expensive ad-hoc integrations, entire applications to incorporate legacy data, and missed opportunity. The problem is all the more substantial because of the vast array of professionals involved with environmental issues, and the diversity of data that must be considered for various kinds of analysis" (Phillip Dibner, pers. com. in: Open GIS Project document 01-012r1). This analysis by a natural resource ecologist might be an explanation for the inadequacy of most present environmental impact studies, especially with respect to biodiversity.

Threat synopsis

Integrated species information systems will allow "data mining that cannot be imagined today" (Edwards et al. 2000). But, as outlined above, there might pass considerable time until these systems will provide all available data with the necessary high spatial resolution needed for efficient planning. Meanwhile, we have to continue with a fuzzy decision approach, which is intuitively followed already by many conservationists. The alarming situation of many migratory species has been outlined, and the major threats are well-known. One does not require huge data sets or sophisticated GIS-analysis to see the disastrous consequences of habitat destruction, pollution, or bycatch by large-scale fisheries. Examples have been presented in the previous chapters, and for individual species within Annex II. The principal threats affecting whole species groups are summarised in Table 5.1.

Tab. 5.1: Cross table for major threats and species groups. "Y" signifies an important threat for the respective group; for details see the respective sections.

EP: Environmental pollution,
AL: agriculture – land conversion,
F: Forestry,
WL: wetland loss,
C: construction,
C-dams: river dams,
FD: fishery – direct,
FI: fishery – indirect,
H: hunting.

Tab. 5.1: Kreuztabelle wichtiger Gefährdungsfaktoren und den betroffenen Tiergruppen. "Y" bedeutet einen beträchtlichen Einfluß des Gefährdungsfaktors auf die Tiergruppe; nähere Beschreibungen und Beispiele findet man in den entsprechenden speziellen Kapiteln sowie in den Legenden des Annex II.

EP: Umweltverschmutzung,
AL: Landwirtschaft – Landumwandlung,
F: Forstwirtschaft,
WL: Verlust von Feuchtgebieten,
C: Bautätigkeit,
C-dams: Staudämme,
FD: Fischerei – direkt,
FI: Fischerei – indirekt,
H: Jagd.

Animal Group
  Habitat conversion Taking
  EP AL F WL C C-dams H FD FI
Bats Y Y Y   Y        
Seals Y         Y Y   Y
Terrestrial mammals   Y Y   Y   Y    
Whales and Dolphins Y         Y   Y Y
Bee-eaters, rollers,
Y Y Y   Y   Y    
Cuckoos Y Y Y            
Hoopoes Y Y              
Nightjars Y Y Y            
Owls Y Y Y   Y   Y    
Pheasants, bustards,
sandgrouses, buttonquails
Y Y     Y   Y    
Pigeons Y Y Y       Y    
Plovers, lapwings, snipes Y Y Y Y Y Y Y    
Raptors Y Y Y   Y   Y    
Seabirds Y     (Y)   Y     Y
Songbirds Y Y Y Y Y   Y    
Swifts and Hummingbirds Y Y Y   Y        
Waterbirds Y Y   Y Y Y Y    
Woodpeckers Y Y Y            
Turtles, crocodiles Y     Y Y Y Y Y Y
Fishes Y   Y Y Y Y   Y Y
Invertebrates Y Y Y Y       Y Y

The most severe threats can be summarised as follows:

Environmental pollution

Herbicide and pesticide use, either for agriculture or for disease control, remains a major threat to practically all groups of migrants. While the use of DDT has been successfully suppressed, other pesticides continue to accumulate within the food chains. Together with organochlorine phosphates, PCBs and a wide variety of other chemical substances, they now can be detected even in pristine ecosystems, such as the Arctic or the Antarctica. Top predators such as seals, whales and dolphins, raptors and certain fish species accumulate huge amounts of chemicals, depending on the regions and their prey. Amazon fish species accumulate mercury from gold mining, and whale meat has such high concentrations of chemicals that it should be forbidden for human consumption. The "International Council for the Exploration of the Sea" ( offers a database of toxic substances found in marine organisms. It demonstrates the impressive variety of chemicals involved, and species affected. It is evident that a successful prevention of chemical pollution, including chemical catastrophes, is extremely important for long-term conservation of most migratory species.

Agriculture land conversion

Because most migrants occupy large areas, they necessarily use agroecosystems at least during part of their life cycle. Many species have adapted remarkably well to traditionally managed areas. But this dependency makes these species particularly sensitive even to apparently small changes in agricultural practice. Most collapses of European bird populations are due to such changes, which have been well studied. They can be remedied remarkably well by extensivation programs, as for the corncrake in England and the Netherlands. Huge problems have to be solved on a global level, due to the rise of new crops and new techniques. Massive changes must be expected from the extension of the European community, and the unavoidable overall extension of agricultural areas. The conflict between wild animals and agriculture will therefore gain importance, and will be among the most difficult challenges to conservationists.

Wetland loss

Rivers and wetlands are under severe threat by increasing demand for water, pollution of water catchment areas and drainage. Wetlands are important key habitats not only for waterbirds, but also for many other bird species and fishes. Mangroves in particular have been transformed at an alarming rate within the last decade, which severely affects marine habitats and species. Booming shrimp aquacultures converted most mangrove habitats in southern East Asia, Ecuador, Central America and parts of Africa in not much more than a decade. Even remote areas have been totally transformed, and probably have affected fish species, turtles, waterbirds and seabirds directly or indirectly (Hardtke 1998).

Dam construction

River dams have led to the immediate collapse of the respective diadromous fish populations. This includes economically important species such as salmon or sturgeon, and led to the breakdown of local fisheries. In addition, freshwater dolphins and some marine mammals with inshore migration (including manatees) are severely affected. Additional effects include the alteration of the entire watershed including wetland complexes and deltas due to upstream and downstream changes of riverbeds,

increased sediment load and higher salinity due to evaporation: one third of the Colorado river flow (Mexico, US) evaporates from reservoirs (McCully 1998). Existing and planned dams often have pharaonic dimensions, and impacts are probably irreversible. The "Three Gorges Dam" (Yangtse, China) is now under construction, and will affect the staging areas of the Siberian crane (Figure A2.45). The huge investments for dam construction in "third world countries" are only possible by international funding from multilateral development banks and export credit agencies (e.g. World Bank, European Development Fund; for an extended list see McCully 1998 (Table 9.2) and World Commission on Dams,


Hunting has been the cause for complete or nearby extinction for several migratory species, such as the passenger pigeon (Ectopistes migratorius). Some other species became exterminated without leaving traces of their possible migratory behaviour, such as Steller’s seacow or the great alk. Hunting is still a severe problem in some parts of the world, such as the hunt for houbara bustard (Chlamydotis undulata) in the middle east (see Figure A2.68). The recent shooting of satellite-tracked birds in France and Germany demonstrates the inadequacy of control, even within CMS member states with highly regulated hunting schemes. Among the shot species were several listed on CMS Appendices, such as a black stork (Ciconia nigra; Appendix II), or the threatened lesser white-fronted goose (Anser erythropus; Appendices I and II), shot at a protected site in Germany (Øien & Aarvak 2001). Though the time and localities of shooting could be identified with high precision, and both cases raised considerable publicity, there was no legal persecution in any of the cases.

Fishery – direct and indirect

Fishery is the most direct and massive way of "taking". Whaling should be included here, because of the strong overlap with respect to habitat and main actors. Though there are extensive legislative frameworks and quotas, fishing is a direct form of massive non-sustainable exploitation. Several once abundant fish stocks collapsed, and with them whole regional economies. Besides the direct threat of the target species, depletion of marine species affects entire marine food webs, and top predators such as marine mammals or seabirds. Whaling is a highly political issue, mainly debated within other international agreements such as IWC and CITES. Memoranda of Understanding and "further research" will not be sufficient to solve these problems, and it is recommended that CMS instruments and legislative frameworks be extended by executive and efficient control instruments, such as the employment of fishery observers or test cases at court.

Finally, global change will severely affect a considerable number of migratory species. This new threat is difficult to measure, predict and to combat. Emerging problems cannot be solved directly. However, the following recommendations should be considered, to minimise catastrophes and species extinction risks:

  1. large populations are necessary to provide the genetic diversity for the necessary adaptation to a changing environment,
  2. maintenance of entire species ranges and potential habitats are necessary, to allow for adaptive changes in migration patterns,
  3. hunting and taking must be reduced, as their effect will be more severe on weakened or concentrated populations.

Concluding remarks

Given the wide ranges of most migratory species, the creation of "protected areas" is not sufficient and will not provide the necessary resilience for a long-term maintenance of viable populations. Many migrants are still numerous and not red-listed. They have adapted to agroscapes and managed to co-exist with humans, but will probably not be able to cope with further intensification and the increased "ecological footprints", in particular of industrialised nations. Therefore, it is not enough and might be even counterproductive to concentrate conservation efforts at certain "biodiversity hotspots", mostly in the tropics. Industrialised nations harbour a considerable portion of migrant biodiversity. But in spite of overdevelopment, they still rely on formulas of "economic growth", which inevitably lead to the further destruction of wetlands, coastal environments, forests and river systems, all of which are of extreme importance for migratory species. Industrialised nations should take a lead in demonstrating that sustainable co-existence of man and animals is possible by developing or re-developing ecologically sound agricultural practices, and minimise ecological footprints of their citizens.


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)