Summary < Introduction > Background: the current state of knowledge about migratory species
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1 — Introduction

Migratory species have fascinated humans throughout history. This has had many reasons. Early men followed the herds of large herbivores which formed their prey. The herbivores in turn followed the fresh vegetation that flourished after rains and in this way escaped from drought or snow. Later in the history of humankind, nomads had to guide their semi-domesticated herds of cattle along similar paths. This practice of 'transhumance' continues up to the present. Other important prey such as birds or fishes appeared in certain seasons in great abundance, often numbering millions of individuals. Humans could not follow them when they disappeared nor understand where they went. Myths about the origin of these concentrations have prevailed right up into modern times, and it was not until the 19th century that scientific documentation and explanations began to appear. However, the mechanisms of orientation, navigation and homing remain essentially mysterious to us even today.

The use of magnetic, solar or stellar compass has been proven experimentally for many species - but still the exact location of the sensory mechanisms for such magnetic perception remains unknown, and the causal chain linking a genetic program to a certain orientation behaviour is not only unknown but even difficult to imagine. Any simplistic, reductionist model is insufficient to understand the ease with which animals switch from magnetic orientation to solar orientation during one journey, or the precision with which imprecise entities of 'flesh and blood' can orientate themselves as well as our most sophisticated silicon-based instruments and satellites. We can identify individual components in animal navigation, but we are far from understanding their integration.

We have a similar problem with respect to conservation. Over the last 50 years, impressive data sets have been compiled, and progress in monitoring by new technologies such as satellite tracking have provided completely new insights by 24h-monitoring, in all parts of the globe, including the deep sea. Huge monitoring programs provide comprehensive data sets for many species, and most of them indicate frightening declines in population numbers. The reasons are not always understood, and many studies end by stating that more research is needed to understand the 'real' causes for a decline. On the other hand, there are many clear cases of over-exploitation by hunting, fishing and ongoing habitat destruction.

The Bonn Convention on the Conservation of Migratory Species of Wild Animals (CMS) has sought to counteract this process by implementing species-specific agreements, and there are impressive success stories. However, most of them refer to flagship species. A silent majority of species and habitats is continuing to decline unnoticed. Scientific research often starts too late, and early warning programs are missing. Integration of scientific knowledge and conservation programs is often haphazard, and other important factors such as political or economic constraints are mostly ignored.

The database project presented here is an attempt to bridge the gap between scientists and conservationists. The Global Register of Migratory Species (GROMS) consolidates our scattered knowledge on migratory species within one relational database and combines it with a geographical information system (GIS). The aim is to reveal where existing information is deficient, to support the Convention on Migratory Species and to contribute to the Clearinghouse Mechanism under the Convention on Biological Diversity. It addresses a wide audience, from the interested public to specialised scientists. Species distribution maps in GIS format make it possible to tackle interdisciplinary questions by intersection with GIS layers of landuse or environmental data. The 'calculation of range states' by a GIS operation presented here is one possible application, and users are encouraged to perform their own analyses. However, it needs to be considered that the GROMS maps are on a global scale, and therefore cannot provide all answers to local or even regional problems of conservation. A caveat to the reader: a database does n o t provide the solution to any conservation problem. It is a tool - one has to ask the right questions, and the answers have to be interpreted critically. In some cases, they might be contradictory, reflecting different data sets or expert opinions. In other cases there is no answer - this highlights the gaps in our current knowledge. This publication can be used in different ways:

Summary < Introduction > Background: the current state of knowledge about migratory species
Zusammenfassung
Résumé
Resumen

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