The main exhibition covers the story of Gotland, from its origins 400 million years ago to today’s Gotland landscape.
Life on an ancient coral reef!
Gotland is a special place. The island is teeming with birds, and abounds in luxuriant blooms and enigmatic rock formations. The limestone-rich earth and the mild climate set the rules for this ecology, but humans have perhaps had the greatest impact on Gotland’s nature, for better and worse.
We hope that Naturum will awaken your questions and curiosity. Will the leafcutter bee survive another season? Is it natural for there to be so many juniper bushes across the limestone plateau, the wide-reaching Alvaret? But most of all we hope that when you return outdoors you will experience nature all over again. The story of Gotland began on a coral reef nearly 420 million years ago. How the story goes from here is up to us.
Welcome in to Naturum Gotland. Welcome out into Gotland’s nature!
The island of Gotland was slowly forged by marine animals in shallow and warm ocean waters some 420 to 430 million years ago, during what is known as the Silurian period. Corals, octopuses, clams, bryozoans and sponges, sea lilies, brachiopods and now extinct trilobites all lived here. They sank to the bottom as they died, and over millions of years this silt on the sea floor was compacted and became hard as stone – in fact, it became limestone. The animals and the plants became fossils in the rock bed. Look down at the stone floor you’re standing on! It is full of sea animal fossils.
Gotland is still moving, at about the rate that your fingernails grow.
All land masses on earth are actually in motion. This is called continental drift. From the tropical ocean south of the equator where Gotland’s limestone mass formed 420 million years ago, the Scandinavian continent has shifted north at a speed of about 2 centimetres per year. The sedimentary deposits from subsequent periods settled on top of this limestone mass. We do not know how deep the future ’Gotland’ sank during that time, but dinosaurs and other now extinct animals lived on its surface. These upper layers, however, have long since eroded, and as a result there are no dinosaur skeletons to be found on Gotland. The bedrock was naturally ground down over the course of the last ice age, and the limestone mass of Gotland resurfaced 10,000 years ago.
PS. The journey continues. 100 million years from now, Gotland will be somewhere near where Siberia is today. Africa will drift northward to connect up with Europe, whilst the American continent will sail away eastward across the Atlantic.
Who governs on Gotland?
Answer: The limestone! The massive limestone of Gotland determines where ground water collects in the earth, where the forest grows best and where the arable fields are distributed. It decides which grasses and which butterflies thrive best, and which birds choose to live here. Limestone dictates how farming is planned, and why so many houses are whitewashed. No limestone, no Gotland!
- Hoburg Marble is limestone from Hoburgen in South Gotland. It is reddish and full of fossils. It is the designated regional stone of Gotland!
- Limestone is a customary building stone in Gotland houses and in the low stone walls traditionally demarcating agricultural land and domestic property. When this stone is cut or sanded down it becomes white and you cannot see any fossils.
- When the surface is polished, the fossils become clearly visible again.
- Sandstone is found only on southernmost Gotland. It is made of ancient sandy soil that has been pressed together into stone. In rare cases it also contains fossils, such as the shellfish here.
- Sandstone is easily hewn, or cut, and is extremely heat-resistant. This is why fireplaces and hearths in the Gotland farmhouses are often built from sandstone from Burgsvik. In the 1600s ’Burgvik furnaces’ were exported to many Swedish and Danish castles. Many fine whetstones, or water stones, were made of sandstone to sharpen axes and knives.
- Have you seen any greystone on Gotland? If so, it was shifted here during the ice age.
They call us Conodonts
Tiny jawless, eel-like fish with razor sharp teeth. We existed for several hundred million years, and in huge numbers during the Silurian period. Loads of us are preserved in just the smallest piece of Gotland limestone. But since we had no skeleton, all that is left of us is our teeth. Our miniscule fangs measure 0.2 to 5 millimetres and can best be seen through a microscope. Because our tiny teeth kept on developing over millions of years, scientists can date the age of a piece of limestone from samples of the rock and our teeth.
But what did we really look like? This is one of natural history’s great riddles. Judging from individual fossils, scientists have tried to make an educated guess. Perhaps like this?
10,000 years is really not a very long time. But the Baltic Sea has changed dramatically over that time. The ice covering Scandinavia began to recede northward 10,000 years ago. The glacier, several kilometres thick, was so heavy that the crust of the earth was thrust downward by the weight. But as the ice lessened, the rock beneath it pushed up from below and broke through the surface of the sea.
The shoals, or rocks, that poked up would grow to become the reefs of Karlsöarna, as well as Högklint outside Visby, Torsburgen near Hemse, and Hoburgen at the southern end of Gotland. Once above sea level, herbs, grasses, birds and insects were first to inhabit the rocky land, and humans arrived later. There is a cave at Stora Karlsö that was home to a Stone Age huntsman 9,000 years ago.
An ailing sea in recovery
The Baltic Sea is a unique inland sea, with fresh water in the north that turns increasingly saline the farther south you travel. Yet it is also quite shallow, with an average depth of only 56 metres. This makes the Baltic Sea particularly susceptible to damage from environmental pollutants and over-fertilization. Compare this to the Mediterranean Sea, which is 1,500 metres deep on average and therefore contains 30 times more water in which to dilute the emissions we spill into it!
Today both pike and cod have all but disappeared from the Gotland coasts, and the sandy white sea floors in many places are covered with slimy algae. The sea is ailing.
But there is good news too. Poisons and an excess of fertilizers have begun to decrease in recent years. Marine wildlife such as the grey seal and the white-tailed eagle, previously at serious risk of disappearing, are a common sight today. Sea bass are increasing in number, and the native bladder wrack seaweed is growing back. Maybe the Baltic Sea is on a path to recovery and will be truly healthy in our own future.
The beach meadow – sea, grass and cows
Sea, hay-making, and grazing animals have formed the beach meadows of Gotland. When the sea washes over the beach it brings seaweed with it, fertilizing the soil. The grazing animals receive nutrient-rich feed and keep the beach meadow open. There is an abundance of birdlife. If the beach meadow is not grazed or cut it quickly becomes overgrown. Then, many birds leave the area and it becomes almost entirely silent in the springtime. Many of the beach meadows on Gotland can be found right here at Sudret.
It´s no coincidence that many birds have chosen the beach meadows as their favourite breeding ground. A throng of small creeping insects thrives in the fine-grained, nutrient-rich earth of the beach meadows. The shallow water also offers a generously-stocked larder.
The Alvar – Gotland´s desert
On the barren limestone ground, known as ”alvar” in Swedish, alpine and Mediterrean plants live side by side. The limestone soil is scanty, sometimes entirely non-existent. In order to survive on this barren ground, plants and animals must be able to withstand intense heat, biting winter cold, extreme drought, and flooding. Get down close to the ground and admire the lichens, herbs and insects that are able to survive in the brutal conditions on the alvar.
No cows, no sheep – no alvar
The alvar´s existence is dependent upon grazing animals to survive, otherwise it becomes overgrown with juniper shrubs, blackthorn, Swedish whitebeam, or pine trees. After the sheep were taken away from the island Stora Karlsö in 1887, the alvar became overgrown. Unlike other alvar, this area has been restored into its original condition. And the sheep are back.
Alvar is a unique type of nature in the world
As much as 71 percent of the world´s alvar is found in Gotland, Öland and Västergötland. Other alvar regions exist in Estonia and North America. Alvar is found all over Gotland, but the most impressive regions are in Sundre, the area around Östergarn and on the island of Fårö.
The meadow – a living monument to the past
The meadow is the living cultural heritage of a way of life, with roots in the Iron Age. In times past the meadow was important for the existence of the farm. Nowadays it doesn’t fulfil the same function, but is nonetheless preserved. For generation after generation our ancestors have preserved their meadows in order to ensure the greatest possible amount of feed for their animals. These persistent efforts have resulted in creating environments comprising the richest numbers of species we have here in Sweden. In a well-tended meadow as many as 50 different kinds of plants and grass can grow within the space of one square meter. Count them for yourself!
The meadow is field´s mother
The more meadows a farm had, the more animals could survive the winter, and the more fertilizer was produced for the tilled fields.
Thus the expression ”the meadow is field ́s mother”. When artificial fertilizer and tractors were introduced (during the first half of the 20th century) meadowland was no longer needed and quite a lot of meadows where brought under cultivation, while others became overgrown. Despite that, Gotland still has many meadows at present, even if only a fraction of what once existed.
The Bog – Nursery, pantry, and sewage treatment plant
”Gotland is not an island. Gotland is a lake.” That´s what Jacob Cederström, County Governor at the beginning of the 19th century thought. Then, more arable land was needed to provide for the growing population. The marshes and swamps were drained and transformed into farmland and meadows. Now, only a small portion of Gotland´s rich wetlands remains. Muskmyr in Sundre is a perfect example.
The wetlands are still extremely important. They soak up excess ground water, and reduce eutrophication by binding nitrogen. Today, old drained bogs are being restored in order to improve the ground water and save the lives of animals. Without water – no life!
Great Fen-Sedge, good roof
In the past, Great Fen-Sedge (Saw-sedge), which grows abundantly on Gotland, was used mostly to roof outhouses and barns. A good thatched roof could last for forty years. The saw- edges of its blades make it hold together well. To prevent rain from seeping in, the roofs were constructed at a very steep angle. Of course, thatching a roof is traditionally a festive event, known as täckating (”a covering/roofing bee”).
The flowering pine forests of Gotland
In the pine meadows there are neither blue berries or lingonberries, nor moss-covered hillocks. Nor are there any elk for that matter. Instead, you ’ll find flowers and lush grass and, in springtime, the ground is covered with mats of blue and wood anemones. The flowers thrive there because of the lime content of the soil. But Gotland also has more sun and less rain than the mainland, making the pine forest here a drier place. Moreover, for thousand of years, Gotlanders have put their animals out to graze in the forest, and they continue to do so in this day. The old, gnarled pine trees are a paradise for both birds and insects.
The first forestry Law
During the 17th and 18th centuries, the pine forests were cut down in order to provide fuel for the growing limestone industry. In addition, Gotland was a significant exporter of timber and tar (causing Gotland to be called ”Little Norrland” at that time).
Grazing livestock hindered the re-growth of the trees. In 1869, as a reaction to the ruthless exploitation of the forests, Gotland recieved the first forestry law ever in Sweden. Nowadays, nearly half of the total area of Gotland is covered by forest.
Lime! Tar! Sniff!
Small lake or large puddle?
The extremely thin soil of the alvar cannot easily absorb rain and melted snow. Small, temporary lakes or ponds, referred to as vätar on Gotland, (literally: wet spots) aret thus created in the depressions in the bedrock. These pools dry out in the summer and lime that had been dissolved in the water is deposited becoming first lime mud, and then micrite limestone. The illustration shows the bottom of a dried out pool with lime mud which has cracked in brilliant patterns. These patterns are accentuated by stones that readily settle in the chequered patterns when the ground alternately freezes and thaws.
One of the plants most characteristic of the alvar is the low- growing dwarf shrub, wild thyme. Its narrow, hard leaves spread their aromatic scent over the expansive landscape. Take a sniff!
But what is that smell?
The seaweed that grows on the ocean floor and pulled out and driven to the shore by strong winds is known as släke in the gotlandic dialect, meaning piles of seaweed. When the släke rots the odor at the beach becomes quite pungent. Take a whiff!
Who is guilty?
Birds and birdsong in all due respect, it is on the ground you ́ll find the real challenge! Here you can see the droppings. Which belongs to which animal? Guess first, then lift the lid for the right answer!