Ecosystem health

Abstract

1. Humans have inhabited the Baltic Sea drainage area for thousands of years, but only in recent decades have the impacts from anthropogenic activities surpassed what could be considered sustainable levels from a Baltic Sea ecosystem perspective. 2. Human-induced degradation of the health of the Baltic Sea ecosystem accelerated in the 1950s. 3. Assessments of the ecosystem state in the 2000s have shown that anthropogenic pressures, which impair the overall ecosystem health are currently present in all parts of the Baltic Sea. 4. The major anthropogenic pressures that have contributed to impoverished biodiversity in the Baltic Sea comprise eutrophication, chemical contamination by hazardous substances and overfishing. 5. Ecosystem regime shifts took place in the Baltic Sea in the late 20th century, primarily due to hunting, fishing and eutrophication, in combination with changes in climatic conditions. 6. Some of the anthropogenic impacts, such as local sewage pollution, contamination by organochlorines and some mammal and bird population declines due to toxins and hunting, have largely been alleviated. 7. However, widespread eutrophication that is evident through bottom hypoxia and shifts in biodiversity is still likely to pose great challenges for the management of the Baltic Sea in the near future. 8. After many decades of scientific research, environmental assessments and political negotiations, international legislation and regional cooperation are currently in force to bring the Baltic Sea ecosystem into a healthier state than it is today.