Visited with the Lakeland Horticulture Society on June 8th, 2014.
The Island of Öland, with flat plains of hard Ordovician limestone, Viking graves and 17th century wooden windmills marking the landscape, could be considered an unusual destination for a garden tour stop. It is because of the combination of forests, meadow, agriculture, and large areas of “limestone treeless pastures,”called the Stora (Great) Alvar, that the geology and flora of the Island of Öland has been observed, studied and recorded by botanist since Carl Linnaeus traveled to the island in 1741.
From Kalmar on the mainland of Sweden we traveled across the 3 ½ mile bridge that connects with Färjestaden on the Island of Öland for a morning exploration to find and photograph the wildflowers of the Stora Alvar. This island that 84 miles (136 km) in length and 9 miles (16 km) at its widest point, is unique in flora and fauna due to the islands geological origins; a submerged island on the sea floor raised out of the “Baltic Ice Lake” approximately 10,000 years after the last ice age. Climate and soil conditions have influenced land use and population since the Stone Age hunters followed wild reindeer and wolves while the land was still connected to a mainland.
On May 15th,1741, Carl Linnaeus set off on a three month summer journey with six students for a scientific exploration of Öland, the Karlsö Islands and Gotland. This summer travel was by request of the Swedish parliament to survey and provide an inventory useful plants, animal, and minerals that were the natural resources of Sweden. Linnaeus also had instructions from the Swedish Board of Manufacturers to look for plants that could be used for dyeing since colors were needed for the textile industry.
Also on the list was to find types of clay that could be used for porcelain as it was an expensive import from China. Finding medicinal plants was also on Linnaeus' list.
Northern Öland is heavily forested with conifer and deciduous trees. Meadows, wetlands and marshlands with rare birds, and hay meadows are also a part of the northern landscape. At the very northern tip of the island there are pine forests (where Linnaeus's charm, the twinflower can be found), ancient oak groves and prehistoric graves. Along the coast line are large limestone boulders. The northern center of the island is suitable for agriculture. It is also the beach resort and tourist area with Solliden Palace (originally built for Queen Victoria), as the summer residence for the Royal Swedish family.
In southern Öland nature reserves have been established in areas of large treeless pasture where flora and fauna is unique; not found on the mainland of Sweden due to the thin subsoil on limestone bedrock. The Stora Alvar, a designated World Heritage Site (due to its unique biodiversity and prehistory) is one of the largest Alvar expanses in the world totaling one hundred square miles (26,000 hectares) on the island. On the Alvar the water supply fluctuates; desert conditions in the summer then autumn heavy rains followed by freezing winter winds which freezes and cracks the thin soil. Plant life is stressed from temperature extremes, nutrient deficiency, dehydration and grazing, but has adapted in unusual ways. Pines, birch, yellow oxytropis, wormwood, rock-rose and mosses and lichens, rooted in limestone slabs, were on the flat plains eight thousand years ago when people migrated from the mainland.
When Carl Linnaeus visited Öland he described the Alvar as a poor but interesting habitat with plants that “flourish on the very sharpest and driest of rocks.” The species that he made note of then can still be found on the island.
Our destination was to explore the edge of the Alvar south of the island village of Vickleby. Initially our scenery was agriculture land with farms. Peony and wild orange poppy were prolific in farmstead yards. Against limestone walls were tall hedges of blooming lilacs. A commercial operation of strawberry picking was taking place in one of the fertile farm fields. The villages and arable land extends along the east and west coast of the island. A strip of coastal grassland used for grazing and sanctuary for birds, is between the farm fields and the sea shore.
Limestone dry stone walls lined the highway for miles as we traveled further south. The scrubby pastures where cattle grazed where delineated by loosely stacked stone walls. Grazing animals are an important function in reducing scrub encroachment on the chalk grasslands that have developed on the shallow soil which is rich in lime but nutrient poor. Plant life on the Alvar plains has been dependent for over two thousand years on the land being grazed and trampled by sheep, cattle and horses. This keeps tall grasses and the common juniper from overgrowing the numerous species on the island that require sunlight and openness.
May and June are the peak months to explore for wildflowers in the Alvar fields in the central southern part of the island. We stopped off the highway at the edge of the “Vickleby Alvar” for a wildflower hunt. This particular Alvar grows a variety of species since it is a combination of bare rock surfaces with sinks and underground streams, gravel, shallow wetlands, moist and dry grasslands, juniper bushes and, thickets of pine and birch. The landscape at the “Vickleby Alvar” site is said to be what Öland may have looked like after the ice caps had retreated and plant colonies were formed on the limestone plains.
Many plants have legends or myths associated with them. The ancient story of the pasque flower (Pulsatilla vulgaris), is that the plant springs up in places that have been soaked by the blood of Romans and Danes because the flower often grows on old borrows and boundary banks.
The pasque flower is a perennial herb of European and Asian origins with upright rhizomes which function as storage organs. The plants roots grow deep into the soil. In the springtime the pasque flower pushes its buds through the earth right after the snow has melted and in a few days blue-violet flowers will appear.
April thru May are the months to see the pasque flowers in prolific bloom on Öland and Gotland so we were late to see their color in mass. There were a few blooms left in early June with the majority of the plants now with light and airy seed pods. The seeds are easily carried by the wind where they can reproduce in the proper environment. The pasque flower can die out from sites that become overgrown, preferring unimproved chalky pastures and grasslands as found in the Öland Alvar.
There are 32 different species of orchids on the island. The first orchids appearing in May and continue for a span of four months. The burnt-tip-orchid (Neotinea ustulatea L.), with the common name due to the burnt appearance of its spike, is a very small meadow orchid with origins of central and southern Europe. It has found its northern most limits in Sweden. The burnt-tip-orchid requires unfertilized and unploughed grasslands as they grow underground for as long as 10-15 years before the first leafy stem will appear. It will be several more years before they flower. If grazing on the Alvar meadow is discontinued though, the orchid will decline as it is a small plant and will not survive in tall grass. The orchid has adapted to the harsh climate of the Alvar with tubers that are storage organs and its thick roots.
The elder-flowered orchid (Dactylorhiza sambucina) is native to Europe; from the Mediterranean to as far north as central Scandinavia. The orchids habitat varies from mountain meadows, pastures, forest border open woodlands and on the Island of Öland, poor grasslands.
The elder-flowered orchid could have been in bloom at the time of Linnaeus visit to the island. He originally assigned the binomial name to this plant in 1745 as Orchis sambucina. The name was amended in 1962 to Dactylorhiza sambucina, since the orchid has two underground tubers, each one divided into several lobes which is characteristic of the genus Dactylorhiza.
The elder-flowered orchid (nicknamed Adam & Eve) is unique as it's blooms are generally yellowish-white but in the same pasture elder-flowered orchids with red blooms can jointly punctuate the landscape. The orchid's flower has no nectar but confuses pollinating insects, especially the bumblebees, as being a nectar bearing plant. Once the bees are aware of that, only a few flowers develop seed capsules. Seed germination is lengthy and requires the presence of a specific fungi.
Orchis mascula, nicknamed appropriately early purple orchids, are the earliest blooming orchids on the island. They contribute to a colorful show on the flat Ice Age plain when it blooms along with the elder-flowered orchid. Both orchids grow where the soil is a little deeper. Like all the orchids on the island they are dependent on Alvar grasslands being grazed. These two European beauties have adapted and made their home in the tough and often inhospitable environment of the Stora Alvar.
Öland rock-rose (Helianthemum oelandicum) is a shrubby sunflower plant of bright flowers blooming from late spring to midsummer; covering then spilling over limestone rocks. The plant has a special tough hard root system which allows it to survive in the gravel that remains from limestone erosion and cope with drought in July. Autumn brings torrential rains and then winter frost cracks the Alvar gravel. The Öland rock-rose is one of the species that Carl Linnaeus's made note of in his 1741 visit.
Along with the rock rose grows a herbaceous perennial with sky-blue blooms, globe daisy (Globularia vulgaris), an alpine plant native to the Mediterranean regions. It prefers open rocky habitats with alkaline, sharply drained soil. With its special root system it survives in the limestone gravel of the Stora Alvar. The globe daisy is a member of the Plantain family and according to the MacDonald Encyclopedia of Medicinal Plants, the leaves of this plant can act as a mild laxative having “purgative, stimulatory, and antirheumatic properties.” In it's history it has also been used in local compresses to heal wounds. In Sweden it is only on the Island of Öland and Gotland that the globe daisy can be found.
In Sweden each province is represented by at least one species of a plant. This idea was adapted from the American State flowers. With the Stora Alvar as the Helianthemum oelandicum only habitat in the world, it is appropriate that the Öland Rock-Rose is the province flower of the Island of Öland.
A wildflower has found to be a marker of the Bronze and Iron Age settlements on the island. The Dropwort (Filipendula vulgaris), is often found in large groups that are situated on prehistoric dwelling sites. It stands above its companion plants that hug the dry grasslands with tiny fluffy white plumes with pink to red tinges, borne on stems well above its foliage. Its starchy tubers on the ends of its roots can store water for the dry periods. Those long root tubers were also used in the days of the Vikings as food and domestic pigs liked to sniff out the tubers and eat them also.
Unique to the Island of Öland is the mauve, short tufted perennial herb alvar chives (Allium schoenoprasum L.var. alvarense) of the onion family. The Latin name for chives was first given by Carl Linnaeus in species Plantarum (1753) and the name of the genus Allium, can be traced back to 184 B.C. when it was the name for garlic. Of more recent note regarding names, A. schoenoprasum L. has been moved from the family of Liliaceae to the family of Alliaceae.
Chives have been cultivated in Europe since the 16th century (possibly earlier), in domestic gardens and are often used for culinary purposes. The plant has an extensive range worldwide. Allium schoenoprasum grows in a variety specific habitats so it was thought that the different populations (ecotypes) could be separate species. Through studies it was determined they were not. The different forms of species were then divided into three morphological types distinguished by the form of the plant and the size of the pollen. On the islands of Öland (and Gotland), the chives on the Alvar are endangered; threatened by increased grazing of sheep so protected. The Allium schoenoprasum whose habitat is site specific; the thin limestone rocky soil of the open grassland of the Stora Alvar, was assigned the subspecies alvarense attached to the binomial name.
White stonecrop (Sedum album), a perennial herb, favors alkaline, calciferous soil so it thrives on the thin soil of the Alvar. The fleshy leaves store water which helps the plant survive long periods of drought,which starts in July on the Alvar. As the photograph shows, the stonecrop's leaves are grape red; a protective pigment to protect the plant in the sun baked environment. July is the month when the most drought resistant species bloom, including the white stone crop. White blooms will top the stems into August.
The Geranium columbinum, nicknamed by the English, Long Stalked Crane's Bill, is a herb with pink to violet flowers found throughout Europe and Western Asia. Eventually it was introduced into North America. The species columbinum (out of 750 known species) prefers moderately dry, nutrient rich calcareous soils. Carl Linnaeus described it as Pelargonium columbinum in his species Plantarum, in 1753.
Kidney vetch (Anthyllis vulneraria var. vulneraria), whose scientific name means 'wound,' may have been a plant that treated wounds centuries past but any medicinal practices were not recorded. Kidney vetch is a creeping biennial herb whose origins reach back to the continental period that followed the Ice Age. Different subspecies have adapted to different soil conditions and climates. Ssp vulneraria preference is free draining chalk and limestone soil and rocky outcrops. It also grows in grasslands that are disturbed but not heavily grazed.
The flower of the kidney vetch is a good nectar source but it takes a larger insect such as the bumblebee to force open its large stiff petals. Kidney vetch was on Linnaeus's list of species that he found in the thin soil of the Alvar.
Carl Linnaeus was an observant traveler writing not only of the flora and fauna of the islands, but of weather conditions, insects, runic stones, rock formations, farmers and their methods of farming, people and their superstitions and local remedies for various diseases. He later published Öland and Gotlandic Journey 1741 (Öländska och Gothländska resa), in 1745.
Carl Linnaeus recorded 311 species of vascular plants during his three weeks of travel on the Island of Öland in June1741. Subsequent botanical interest in the 19th century was driven by the potential to find species new to the island or the Swedish mainland. By the early 20th century the study of the vegetation of the island had become comprehensive. The environment and climate conditions (ex. frost heaving and water support of desert plants) in relation to the flora and vegetation on the Alvar were studied. Lichens and mosses were identified as part of the plant community. By the 1930's at least 1100 species of vascular plants were documented on the island.
An ecological research station (currently Ecological Research Station Linné, an independent foundation) was founded on Öland in 1963 under the guidance of Uppsala University. Research on the role and actions of populations since the Bronze Age that effected the Alvar's have been one of the important studies. A 19th century example was the occurrence of a reduction of the population on the island from 1881-1910 when approximately 13,000 people left the island for North America. Land usage – grazing and cutting of trees, was reduced or abandoned. This resulted in an increase of shrubs and the junipers on the Alvar. As a result there was a decline of the important plant species on the Alvar and a loss of biodiversity. When large scale restoration and management programs were funded and grazing was reintroduced, the plant species on the Alvar pastures were increased.
We concluded our visit on the Island of Öland eating lunch at picnic tables that shared the land with nearby Bronze Age burial mounds and wooden windmills. To the east were flat plains dotted with scrubby juniper bushes on the limestone plains. A glance to the west and the panoramic view was cultivated farm land with the deep blue of the Baltic Sea beyond; a similar contrast in views that Linnaeus would have perceived as he traveled the same southern trail in 1741, from July 4th-7th.
We did not have time to travel further south (as Linnaeus would have), to the larger burial grounds of Mysinge and Gynge. We needed to return to the port city of Oskarshamn for the three hour afternoon ferry ride to the medieval city of Visby on the Island of Gotland. By late evening we were settling in to summer cabins at Toftastrand Pensionat, located on the sandy western shores of Gotland on the Baltic Sea where the summer sun only momentarily sets.
Photos by George Feather and Deborah McMillin
References
Chiej R, “The MacDonald Encyclopedia of Medicinal Plants,” MacDonald & Co. LT D, Maxwell House, London
Jansson, Thorsten, “ Welcome to Stora Alvaret,” The Kalmar County Administrative Board
NatureGate, http://www.luontoportti.com
Rabinowitch, Halm D. & Brewster, J.L., Onions and Allied Crops:Biochemistry Food Science Minor Crops, Volume 3, CRC Press 1990
Raven,Sarah, Wild Flowers, Bloomsbury, London
Rosén, Ejvind, Shrub expansion in alvar grasslands on Öland, Acta Universities Upsaliensis
Sjögren, Erik, Studies of vegetation on Öland, Acta Universities Upsaliensis
http://www.kew.org/science-conservation/plants-fungi/neotinea-ustulata-burnt-tip-orchid