Lutra 47(2)_Editorial_2004

Sousliks

It is no easy task to understand fluctuations in population density and the mechanisms underlying the disappearance, (re)colonization and successful dispersal of species. Often tremendous efforts are necessary in order to gain insight in these processes, they include sampling many variables, radio tracking numerous individual animals, or the patience to wait for the outcome of observations consistently collected over a long time span. Insight into such ecological mechanisms is, however, indispensable to draw conclusions about population viability and the possibilities for the survival of a species. In recent times our knowledge about the distribution of most species has improved considerably. However, all efforts to further improve our knowledge about species distribution remain highly relevant, especially in the case of rare or little known species. The collection of data on the distribution of the European mink in northwestern Spain by Zabala et al. is a good example. Keeping track of the distribution and density of the species will be the next step. Ideally, when monitoring a species, different and consistent sources of information can be drawn on. Such possibilities are well utilized by Camphuysen, who discusses the situation of the harbour porpoise in Dutch coastal waters, based on data of stranded animals, recordings from birdwatchers and at-sea observations.....