Stora Karlsö is a one mile by one mile windswept island situated four miles off the west coast of Gotland, which, in turn, is located approximately half-way between Sweden and Latvia, one hundred miles south of Stockholm. It rises 170 feet (52m) out of the sea with steep limestone cliffs, with a delicate, alvarian biotope ontop. Jeff Ranara, my adviser here, was thoughtful enough to place me on the list for the first ever all-staff trip of the Stockholm Resilience Center, all expenses paid.
The goal of the trip was to allow staff to decompress, develop new relationships, and discuss the success and future progression of the Center. The trip was coordinated by Olof Olsson, deputy director of the Stockholm Resilience Center, in conjunction with Henrik Österblom, Jonas Hentati Sundberg, and Martina Kadin, who have been working on the Baltic Sea Bird study on Stora Karlsö. We were treated to amazing scenery, delicious food, and even live music by Jonas and one of the park rangers, who grew up on Gotland together.
The sea bird study was started by Olof Olsson in 1997, one of the first studies of pelagic birds in the Baltic, it sought to use the birds as an indicator species for the Baltic ecosystem. One exceptional development in the study was the construction of a 4-story bird-nesting shelter, grafted to the cliff side, that allows researchers to access roosting mures throughout their lifespan. This is achieved by providing man-made nesting ledges on the outside of the structure which are accessed via small doors from the inside of the structure. Birds can be banded, weighed, and counted year after year.
The survey house is accessed from the top of the cliff, near the lighthouse, and descends several stories before the survey levels are reached. The island provides refuge for countless sea birds as well as other species, and typically the majority of beaches are closed to foot traffic in order to protect the nesting sites. Fortunately, by early September, these sites are opened, and we had unrestricted access to the entire island.
The preservation plan that protects Stora Karlsö was started by Willy Wöhler, in 1880. He convinced many well-to-do Swedes of the natural value of the island, and began restoration work shortly thereafter. Interestingly, with the removal of the substantial sheep flocks, the ecosystem did not return to its native balance, but quickly became overgrown with Juniperus vegetation. This called for a managed re-introduction of some sheep in order to curb the developing monoculture. Today sheep continue to graze the island, albeit in limited numbers (approximately 300-500 per season).
One remarkable tree, sited in the ruins of an old burial mound is known as the Linnaeus Ash, a specimen of the species Fraxinus excelsior. It served as a navigational aid for many years, and has been reinforced with concrete from time to time, as was common practice in with older trees Sweden for quite some time.
The flora of Stora Karlsö is noteworthy for several rare wildflowers, its stark alvar environment, and for evidence of neolithic inhabitation. Besides the numerous burial mounds, excavations have also revealed numerous bronze-age implements and other acheological evidence of continued inhabitation, that continues into the present under the preservation management system.
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