Extensive sampling (450 grabs) was performed all over the inner part of Puck Bay (105 km2 area) in summers of 2007–2009. The GIS-based analysis of samples was performed to assess in detail the distribution of 32 benthic species. The minimum area of occurrence was less than 1 km2 for Lekanosphaera rugicauda and the maximum was 83 km2 for Cerastoderma glaucum. The material reveals that species with the pelagic larval stage were most widespread, with the least distance between individuals and the highest average density (e.g. Cerastoderma glaucum, Hydrobia ventrosa). The most isolated and the least dense species within the studied area were discretely mobile, non-larval crustaceans (e.g. Gammarus oceanicus and Lekanosphaera rugicauda), present at single sites with the largest distance from each other. We conclude that analysis of species distribution helps in understanding the threats to populations of marine invertebrates and marine spatial planning, through locating the isolated species and populations.
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The Natura 2000 sites and the Coastal Landscape Park in a shallow marine bay in the southern Baltic have been studied in detail for the distribution of benthic macroorganisms, species assemblages and seabed habitats. The relatively small Inner Puck Bay (104.8 km2) is one of the most thoroughly investigated marine areas in the Baltic: research has been carried out there continuously for over 50 years. Six physical parameters regarded as critically important for the marine benthos (depth, minimal temperature, maximum salinity, light, wave intensity and sediment type) were summarized on a GIS map showing unified patches of seabed and the near-bottom water conditions. The occurrence of uniform seabed forms is weakly correlated with the distributions of individual species or multi-species assemblages. This is partly explained by the characteristics of the local macrofauna, which is dominated by highly tolerant, eurytopic species with opportunistic strategies. The history and timing of the assemblage formation also explains this weak correlation. The distribution of assemblages formed by long-living, structural species (Zostera marina and other higher plants) shows the history of recovery following earlier disturbances. In the study area, these communities are still in the stage of recovery and recolonization, and their present distribution does not as yet match the distribution of the physical environmental conditions favourable to them. Our results show up the limitations of distribution modelling in coastal waters, where the history of anthropogenic disturbances can distort the picture of the present-day environmental control of biota distributions.
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Seven major types of sea space use (Nature Protection Measures, Fisheries Exploitation, Geological Exploitation, Recreation, Large Infrastructures, Navigation, Military uses) in the Polish Marine Areas are presented in terms of how much space is used (km2) for each use and the degree of overlap among the different uses. The greatest degree of conflict is noted with regard to Nature Protection (which overlaps with 60% of the areas used for Recreation and Geological Exploitation), and Fisheries Exploitation (which overlaps with 60% of the areas used for Nature Protection, Recreation, Infrastructure and Navigation). On the other hand, Fisheries Exploitation areas are the least disturbed by other users, and its major competitor is Nature Protection, which claims 20% of the areas used by fisheries. A GIS-based map that illustrates the degree of conflict is included, and the authors suggest participatory management as the proper way to minimize conflicts over sea space use and to promote the effective protection of natural resources.
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