Challenges of biodiversity inventories in mosaic archipelagoes - a case study from the northern Baltic Sea

Abstract

The mosaic archipelagoes, high water turbidity, variable benthic habitats and very long shoreline of the Northern Baltic Sea make it costly and technically challenging to collect data that is useful for decision making concerning conservation and sustainable use of the marine environment. The Finnish Inventory Programme for the Underwater Marine Environment (VELMU) has gathered information on species, communities and habitats during 2004-2016 from over 122,000 observation points. The data consists of 95,600 points made with drop-video or ROV, 23,200 with dive line points (from ca. 2000 dive sites), 1850 fish larvae sampling sites, >1000 benthos samples, 780 geological sediment samples, and 20,000 km of acoustic profiling (e.g. echosounding). In addition, satellite observations, LIDAR, aerial imaging with drones and automatic video platforms were used or tested. The majority of the data has been published in an open map service (https://paikkatieto.ymparisto.fi/velmu). We present our national sampling design, by which the majority of data was collected cost-effectively in a 5 year time span (2011-2015). We show examples of our results, such as geographical distribution maps and spatial models for species, habitats, biodiversity and environmental factors. We also explain how the VELMU data has been used in marine spatial planning in the Finnish sea area. In the planning process, areas with high nature values were identified and given a high conservation priority, while other areas were identified as more suitable for human activities, such as aquaculture, wind energy production and ecotourism. Based on our 13 years long experience we review the challenges of mapping species and habitats in complex marine environments, and provide a checklist for establishing a successful inventory programme in such conditions.

Evaluation, Gap Analysis, and Potential Expansion of the Finnish Marine Protected Area Network

“…The Quark, located in the middle of the Gulf of Bothnia, acts as a dividing biogeographical line between the north and south, beyond which survival of many marine species becomes impossible. Continuing south from the Quark, the Archipelago Sea with its 52,500 islands constitutes one of the most complex archipelago systems in the world (Viitasalo et al, 2017). In contrast to the north, marine areas in the south are more impacted by various physical and humaninduced pressures that weaken water quality.…”

“…Finland has an important role in the conservation efforts of the Baltic Sea, not only because of the long coastline (48,000 km) and large number of islands (∼100,000) (Viitasalo et al, 2017), but also because Finland has since 1930 systematically developed its protected area network. Presently 10% of the Finnish sea areas (including EEZ) are under protection.…”