Temporal development of coastal ecosystems in the Baltic Sea - an assessment of patterns and trends

Abstract

Coastal areas are amongst the most biologically productive aquatic systems worldwide, but face strong and varaible anthropogenic pressures. Many marine ecosystems worlwide has gone through substantial structural changes during recent decades, but few studies have addressed the temporal development of coastal ecosystems in an integrated context. The current study represents a first example of a coordinated assessment of ecosystem development in 13 coastal systems of the Baltic Sea. The data covers different geographical areas, ranging from the Kattegat and Skagerak in the southwest to the Bothnian Bay in the north, covers between two to five trophic levels per area, and include time series dating back to the early 1990s. Using multivariate analyses, we assess the temporal development of species abundance or biomass at different trophic levels in relation to the development of variables related to local and regional climate, hydrology, nutrient loading and fishing pressure. Our results highlight the relative timing of change in ecosystem structure and the development of key biological elements across areas. Besides describing the temporal development of coastal ecosystems in the Baltic Sea during the past two decades, our results also highlight limitations and gaps in available monitoring data to support integrated environmental status assessments of Baltic ecosystems as required in current international directives as the Baltic Sea Action Plan and Marine Strategy Framework Directive, as well as the potenital for further developing multisectorial management advice in coastal ecosystem