Along Sweden's southeast coast in the enchanting archipelago of Blekinge county lies the Tromtö-Almö Natura 2000 area. Covering more than 33 square kilometres, including 23 square kilometres of vibrant marine environments, the site is a treasure trove teeming with ecological richness. It offers sanctuary for nesting and resting birds, as well as endangered insects.
To delve deeper into the wonders of this natural haven, we spoke with Anothai Ekelund from Blekinge's County Administrative Board (CAB).
Hi Anothai, and thanks for joining us. Can you tell us more about Tromtö-Almö's unique environmental
Tromtö-Almö is an extensive area that includes several nature reserves and is bordered by other Natura 2000 sites, such as Haglö, Ivö, and Vambåsanäs. The peninsula is renowned for its substantial coastal forests dominated by majestic beech trees, interspersed with diverse oaks and alders. Amid these lush woodlands, beautiful large expanses of grazed coastal pastures and meadows burst with delicate and rare plants, attracting a myriad of insects—a perfect breakfast buffet for birds.
In addition to its terrestrial wonders, this coastal Natura 2000 area harbors several wetlands that are not only rich in biodiversity but also provide crucial ecosystem services such as water purification and water retention. Their high water retention capacity will play a vital role in reducing the risk of flooding and enhancing resilience to drought in future climate change scenarios.
Adjacent to the Natura 2000 area, Listerbyån, a nearby watercourse, flows into the marine environment. Its river mouth, or estuary, features a mix of freshwater and saline seawater, creating a complex habitat that supports both marine and brackish organisms. Estuaries like this are crucial for migratory fish species such as salmon (Salmo salar), trout (Salmo trutta), eel (Anguilla anguilla), and lamprey (Petromyzon marinus).
Moreover, the estuary serves as critical spawning and nursery grounds for northern pike (Esox Lucius) and bream (Abramis brama), while also providing essential foraging and wintering areas for many bird species.
What makes the underwater ecosystems here so special?
Tromtö-Almö is a truly unique mosaic of habitats under the surface, ranging from muddy sediments to rocky bottoms, with depths plunging to 18 metres in the outer archipelago. At the heart of this marine diversity are key habitats like expansive mudflats, serene sandflats, tranquil coastal lagoons, and resilient reefs.
These diverse environments support a rich tapestry of plant communities. The submerged, soft-bottom meadows feature hornwort (Ceratophyllum demersum), sago pondweed (Stuckenia pectinate), Eurasian watermilfoil (Myriophyllum spicatum), and eelgrass (Zostera marina). Towering forests of brown perennial microalgae such as bladderwrack (Fucus vesiculosus), and delicate stoneworts (Charales) also thrive.
These underwater habitats provide protective structures for essential spawning and nursery grounds for coastal-living predatory fish species such as northern pike (Esox lucius) and perch (Perca fluviatilis). The species are ecologically important as they regulate the numbers of smaller fish such as stickleback (Gasterosteus aculeatus). The hard-bottom substrates and reefs also serve as a spawning area for herring (Clupea harengus). Herring has a significant role in the ecosystem as a food source for other fish, birds and marine mammals.
In this intricate web of life, these fish species play a pivotal role in maintaining the delicate ecological balance of the Baltic Sea.
Forests of microalgae form part of diverse tapestry of underwater plant life. Photo: Anothai Eklund.
Stickleback (Gasterosteus aculeatus)
Herring (Clupea harengus)
Northern pike (Esox lucius)
Can you tell us more about the bird species that find refuge in Tromtö-Almö?
The exposed mudflats and sandflats that lie west of Slätthammar’s swimming area and the lagoon south of Hammarholmen on Almö, are crucial foraging areas for ducks and waders. Sheltered bays host large flocks of wintering seabirds like the common pochard (Aythya farina), and the site holds particular significance as a wintering area for tufted ducks (Aythya fuligula) and smews (Mergellus albellus).
The outer archipelago, with its exposed islets and small islands, serves as an important nesting and breeding site for threatened species such as the Caspian tern (Hydroprogne caspia) and the Baltic lesser black-backed gull (Larus fuscus fuscus), both of which are listed as vulnerable on HELCOM’s Red List.
Smew (Mergellus albellus)
Lesser black-backed gull (Larus fuscus fuscus)
Common pochard (Aythya farina)
What are the primary threats to this fragile ecosystem, and how are they being managed?
While Tromtö-Almö's sheltered coastal areas boast high diversity of flora and fauna due to high nutrient concentrations and water temperatures, they face significant threats from climate change, eutrophication, and human activities like dredging, boating and construction of harbours, piers and docks. Rising temperatures and nutrient levels can lead to oxygen-depleted conditions and degradation of vital habitat-forming vegetation.
To counter these challenges, stringent regulations are imposed on fishing, construction, and recreational activities, especially in vulnerable zones. The area is particularly sensitive to extensive fishing of coastal predatory fish, which could trigger adverse cascading effects that profoundly and negatively impact the dynamics of the entire ecosystem.
Additionally, wintering birds are vulnerable to disturbances from boat traffic and other human activities. Protecting these species necessitates minimizing human interference during crucial periods, such as breeding and nesting seasons.
The area is particularly sensitive to extensive fishing of coastal predatory.
Photo: Robert Ekholm.
So, what strategies are crucial for ensuring Tromtö-Almö’s long-term sustainability?
Tromtö-Almö's diverse landscapes and rich biodiversity underscore its significance in both regional and global conservation efforts. The variety of habitats, from deciduous forests to underwater ecosystems, supports a wide array of species, many of which are threatened or vulnerable.
The site is not only rich in biodiversity and vital for species, but also they also provide critical ecosystem services such as water purification and retention. For future climate change scenarios, their high water retention capacity could help to reduce the risk of flooding and enhance resilience to drought.
To ensure its long-term preservation, effective conservation strategies need to be implemented alongside increased community involvement. Public awareness and education about the ecological importance of the area can promote sustainable practices, garner support for conservation measures, and protect biodiversity.
Continued monitoring is also essential to be able to grasp the dynamic changes within these ecosystems and to adapt management practices accordingly.
Tromtö-Almö stands as a beacon of natural beauty and biodiversity, offering insight into the delicate balance of life in coastal and marine environments. By addressing its environmental challenges through dedicated conservation efforts, we can secure the future of this ecological gem for generations to come.
Red List species
Among the species listed in this article, the following are identified in HELCOM’s Red List as they face the threat of extinction due to human activities or natural environmental variability. These species are in urgent need of special attention and protection efforts:
Birds:
Tufted duck (Aythya fuligula) – near threatened
Caspian tern (Hydroprogne caspia) – vulnerable
Baltic lesser black-backed gull (Larus fuscus fuscus) – vulnerable
Fish and lampreys:
Eel (Anguilla anguilla) – critically endangered
Lamprey (Petromyzon marinus) – vulnerable
Salmon (Salmo salar) – vulnerable
Trout (Salmo trutta) – vulnerable
Herring (Clupea harengus) – least concern
Macrophytes:
Bladderwrack (Fucus vesiculosus) – least concern
The area of the Tromtö-Almö nature reserve
The area within the Natura 2000 site that is a marine environment
The area within the Natura 2000 site that is a marine environment
The area within the Natura 2000 site that is a marine environment
The area within the Natura 2000 site that is a marine environment
The area within the Natura 2000 site that is a marine environment
The greatest depths reached in the outer archipelago
The area within the Natura 2000 site that is a marine environment
Species protected under the EU Habitats and Birds Directives
Species protected under the EU Habitats and Birds Directives
The area within the Natura 2000 site that is a marine environment
Species protected under the EU Habitats and Birds Directives
