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

Abstract

Marine Protected Areas (MPAs) are essential for safeguarding marine biodiversity. Various international and regional agreements require that nations designate sufficient marine areas under protection. Assessing the functionality and coherence of MPA networks is challenging, unless extensive data on species and habitats is available. We evaluated the efficiency of the Finnish MPA network by utilizing a unique dataset of ∼140,000 samples, recently collected by the Finnish Inventory Programme for the Underwater Marine Environment, VELMU. Using the quantitative conservation planning and the spatial prioritization method Zonation, we identified sites of high biodiversity and developed a balanced ranking of marine conservation values. Only 27% of the ecologically most valuable features were covered by the current MPA network. Based on the analyses, a set of expansion sites were identified that efficiently complement the ecological and geographical gaps in the current MPA network. Increasing protected sea area by just one percent point, would double the mean conservation cover, and specifically increase the protection levels of habitat types based on IUCN Red List of Ecosystems, key species, threatened species and fish reproduction areas. We also discovered that a large part of ecologically valuable species, such as many brown and red algae, blue mussels and eelgrass, exist in the underwater parts of rocky islands and sandy shores. These areas do not belong to the present (Finnish) interpretation of the habitats (e.g., reefs and underwater sandbanks) listed in the EU Habitats Directive. Neglecting these environments may lead to lack of protection of functionally important biodiversity. We emphasize that, in addition to establishing MPAs, also ecosystembased marine spatial planning is needed to safeguard the integrity of marine biodiversity in the northern Baltic Sea. The spatial prioritization maps produced in this study are essentially environmental value maps which can also be used in impact avoidance, such as siting of wind energy and aquaculture, or in avoiding overfishing in the most valuable fish areas. Our approach and analytical procedure can be replicated in the Baltic Sea or elsewhere provided that sufficient data exist.

Ecological coherence of Marine Protected Areas: New tools applied to the Baltic Sea network

“…When applied to the HELCOM MPAs an optimal extension of 3% of the total protected area (Figure ), most of the suggested extension includes the Swedish coast and the Finnish coast along the Baltic Proper and Bothnian Bay, as well as in the Archipelago Sea. Interestingly, many of the new areas in an extended network (Figure ) approximately coincide with a recently suggested extension of MPAs along the Finnish coast based on a prioritizing analysis of biodiversity and habitats (Virtanen et al, ). This overlap is probably fortuitous since the MPAs are based on different criteria (although high connectivity may be correlated to biodiversity), but together give strong support for a future extension.…”

“…Although connectivity has for some time been highlighted as important to provide such network persistence, a clear framework has been lacking about how to include information on connectivity in the design of MPAs. Suggested approaches to implement connectivity range from rules of thumb based on assumed dispersal distance (Shanks et al, ), GIS models of number of connections for set distances (HELCOM, ), advanced graph theory (Treml et al, ), source–sink analyses (Dubois et al, ), to weights in cost–benefit calculations in conservation prioritization tools (Beger et al, ; Virtanen et al, ). We have added another possibility.…”

“…If habitat information is available, e.g. presence–absence or habitat quality (Virtanen et al, ), this can easily be incorporated (Berglund et al, ; Jahnke et al, ).…”

“…The present lack of habitat mapping or species distribution models for most marine areas is a further bottleneck in the assessment of connectivity, although some recent, mainly regional, mapping shows great promise (e.g. Virtanen et al, ). However, the tools presented here are all based on the connectivity matrix, which may be estimated using other methods, e.g.…”

“…Adequate MPA size has been estimated from dispersal distance based on mark–recapture (Jones, Milicich, Emslie, & Lunow, ), pelagic larval duration (Shanks et al, ), genetic divergence (Underwood, Smith, van Oppen, & Gilmour, ), genetic assignment (Berument et al, ), and through biophysical models that include critical larval traits such as larval drift depth (Corell et al, ; Ross, Nimmo‐Smith, & Howell, ). The assessment of sufficient network connectivity is more challenging and ranges from genetic assignments (Planes, Jones, & Thorrold, ), habitat distribution (Sundblad, Bergström, & Sandström, ; Virtanen, Viitasalo, Lappalainen, & Moilanen, ), and biophysical models combined with metapopulation dynamics (Jonsson, Nilsson Jacobi, & Moksnes, ) or network theory (e.g. Treml, Halpin, Urban, & Pratson, ).…”