This Special Issue of Water, Air and Soil Pollution offers original contributions from BIOGEOMON, an international symposium on ecosystem behavior and the evaluation of integrated monitoring of small catchments, held in Prague, Czech Republic, in September 1993. The meeting attracted nearly 200 scientists from 27 countries on five continents. BIOGEOMON was a loose continuation of another international meeting, GEOMON, which was held in Prague in 1987. Both sym posia provided a forum for the discussion of ideas on environmental problems in western and eastern Europe, with important contributions from the American continent. With the dramatic collapse of the iron curtain, it was our hope that more so than GEOMON, BIOGEOMON would provide opportunities for the free exchange of ideas, fostering the development of research collaborations between its participants. With international openness comes the increasing realization that every indus trialized nation has its own legacy of environmental degradation. Anthropogenic impacts differ in severity and scale; air and water transport of pollutants transform local impacts into regional and global ones, ignoring political boundaries and eco nomic differences. Environmental consequences of anthropogenic activities often are detectable at the ecosystem level. Thus, the challenge of ecosystem science, and to the individuals who practice it, is to develop a comprehensive understanding of ecosystem function in the past and at present, and to apply such understanding toward minimizing future insults to the local, regional, and global environment.

The BIOGEOMON conference, held in Prague, September 1993, was dedicated to the use of geochemistry and biology in the elucidation of biogeochemical processes in the context of research on small catchments, which are natural systems that lend themselves to the study of environmental problems at the ecosystem level. Biogeochemical Monitoring in Small Catchments, which contains reviewed papers from the conference, includes long-term studies of nutrient cycling in forested catchments, effects of anthropogenic action on streamwater chemistry, stable isotope studies for tracing biogeochemical processes, determination of the process rates, and mathematical modelling of ecosystem behaviour and mass fluxes. For research scientists and students of ecology, biology, hydrology and geochemistry as well as professionals in natural resources management.