Wildlife of
Åland Islands

Primary Threats

• Eutrophication is a dominant pressure in Aland's sheltered bays and inner archipelago: nutrient inputs from agriculture (fertilizer/manure runoff) and scattered coastal settlements/cottages can elevate nitrogen and phosphorus locally, while large background loads arrive from the wider Baltic. This drives algal blooms, oxygen depletion in bottom waters, and reed overgrowth that degrades fish spawning/nursery areas and shore meadows. Marine litter and microplastics also accumulate along shorelines, and maritime traffic brings chronic risks of oil/chemical spills.
• Warming and reduced winter ice cover in the Baltic affect ice-dependent and cold-adapted ecology: ringed/seals and coastal food webs can be impacted by poorer ice conditions, and changing temperature/salinity alters fish distributions (affecting pike/perch/pikeperch and herring dynamics). Longer warm seasons can intensify cyanobacterial blooms, while sea-level rise and stormier conditions increase shoreline erosion and flood risk for low-lying coastal habitats and infrastructure.
• Coastal habitat loss and fragmentation occur through shoreline development (new housing/summer cottages), marina/harbor expansion, dredging of shallow bays, and shoreline hardening. These changes disproportionately affect the shallow, sheltered inlets that function as key spawning and nursery habitats for coastal fish and as feeding areas for waterbirds.
• Recreational boating, kayaking, shoreline visitation, and tourism can disturb sensitive nesting and moulting birds on small islets (common in the outer archipelago). Disturbance is especially acute during breeding season when repeated landings near colonies reduce breeding success and increase predation exposure.
• Coastal fisheries (commercial and recreational) can pressure local stocks and age structure of key species (e.g., perch, pike, pikeperch, and herring), particularly in enclosed bays where populations are more localized. Baltic-wide stock fluctuations and ecosystem changes (driven by climate and eutrophication) can compound local harvest impacts.
• Invasive predators and competitors are a major concern on islands: American mink (and locally also raccoon dog where present/arrives) can devastate ground-nesting seabird colonies. Invasive plants (e.g., garden escapes along shores and roadsides) can alter coastal meadow composition. Marine invasives carried by shipping/boat traffic (and changing salinity/temperature) pose ongoing risks to brackish communities.
• Historically managed coastal meadows and wooded pastures can degrade when traditional grazing/mowing declines, leading to scrub encroachment and loss of open-habitat biodiversity. Conversely, eutrophication-driven reed expansion modifies shallow bays, reducing open-water mosaics crucial for fish and birds. Small-scale drainage/ditch maintenance can also alter wetland hydrology.
• Maritime infrastructure and transport corridors (shipping lanes, ports, dredged fairways, undersea cables) can disturb seabed habitats and increase underwater noise and spill risk. Onshore, road access, causeways, and coastal engineering can fragment habitats on larger islands. Renewable energy development (e.g., wind power planning) can create collision/displacement risks for birds if poorly sited in migration and feeding areas.
• Waterfowl hunting and seal management/culls (where permitted/implemented) can add mortality to populations already stressed by food-web changes and disturbance. The impact is context-dependent but can be significant for localized or declining seabird/waterfowl groups if not tightly regulated and monitored.
• Outbreaks such as avian influenza periodically affect seabird and waterfowl colonies in the Baltic region; Aland's dense nesting aggregations on islets can enable rapid spread and high mortality in some seasons.
• While Aland's agriculture is not large-scale by continental standards, intensification or expansion of production on limited arable land can increase nutrient runoff and reduce semi-natural habitats (field margins, meadows) that support pollinators and farmland biodiversity.
• Urban growth is concentrated (notably around Mariehamn), but even modest expansion in an island context can disproportionately increase coastal development pressure, traffic, and wastewater/stormwater loads into nearby bays.
• Forestry operations on the larger islands can simplify forest structure and reduce deadwood-dependent species if management favors uniform stands. Fragmentation from forest roads also increases edge effects and can facilitate the spread of invasive plants.