Husgärdessjön

Vallesjöarna bildas

“The Vallesjöarna lakes were formed when the several kilometers thick inland ice (up to 3.5 km) began to retreat northward around 20,000 years ago, eventually creating a bay in the Valle area. The landscape was depressed by the thick inland ice, but as the ice started to melt, the land surface began to rise, and the sea receded. The fertile clay soils in the Skara and Vara regions were formed when the area was once a seabed.

However, about 12,600 years ago, the climate became colder again, and the ice edge became stationary here in the Valle area (in the so-called central Swedish ice marginal zone).” The period when this occurred is called the Younger Dryas, approximately 12,800 to 11,600 years ago.

Large quantities of moraine in the form of glaciofluvial sediment, boulders, stones, and gravel that were transported with the ice and then deposited inside the ice in so-called sinkholes/glacial potholes, were left behind at the ice edge, shaping the landscape through the formation of features like kame hills, eskers, and moraine ridges. Large deposits parallel to the ice front created marginal fields that were several kilometers long and up to 10 meters high.

The landscape type is called ‘kamelandskap,’ derived from the Scottish word ‘came,’ which means ridge or crest. A kamelandskap is a hilly landscape with a multitude of ridges, hills, and depressions containing deep lakes, up to 26 meters deep. Other depressions are now wetlands (ranging from poor marshes and bogs to extremely rich fens). The Valle area is situated along the Billingen mountain, which resisted the forces of the inland ice and glacial rivers thanks to its ‘cap’ of volcanic rock, typical of the so-called plateau mountains.

Large blocks of inland ice, along with the sediment that accumulated around them, formed so-called dead-ice pits when the ice blocks melted. Even today, traces of these can be seen in Valle. Several beautiful dead-ice pits can be found in the nearby nature reserve Ökull-Borregården. Some of the smaller round lakes may have been formed in this way.

The drainage of the Baltic Ice Lake.

Another phenomenon that has also contributed to the landscape in Valle is the so-called drainage of the Baltic Ice Lake. Vast amounts of meltwater that had accumulated in the area east of what we now call the Baltic Sea were then rapidly emptied into the ocean through openings formed between the ice and the higher terrain to the south. When the water gushed out over this area between Lake Vänern and Lake Vättern, the landscape was shaped into what we see here today.

When the inland ice retreated, it left behind a lush landscape with abundant animal and plant life, which led people to settle here nearly 10,000 years ago, as evidenced by a multitude of ancient remains.

Connected lake system.

During that time, the Vallesjöarna lakes were fewer and more interconnected than they are today, as agricultural activities led to the drainage of the land. The shallow Hornborgasjön was practically gone before the restoration work of it began in the late 1980s. Today, there are about 40 lakes in the Valle area, and Husgärdessjön is among the largest.

The unique nature of the Valle area has made it of national interest for conservation and outdoor activities, resulting in a total of 8 nature reserves in the region today. Lycke-Lilla Höjen, Jättadalen-Öglunda Cave, Eahagen/Öglunda Meadows, Torp, and Höjentorp-Drottningkullen have been nature reserves since 1975. Gullakrokssjöarna became a nature reserve in 1999, while the nature reserves Ökull-Borregården (located near Valle Camping and Husgärdessjön) and Bockaskedeåsen-Toran were established in 2007. The Valle area is considered to have particularly favorable conditions for enriching experiences in natural and/or cultural environments, as well as for outdoor activities, thus providing enriching experiences.

Inflow and outflow.

The water in Husgärdessjön is replenished within the course of 1-2 months. The lakes in the Valle area are groundwater lakes that receive water inflow from streams flowing down from Billingen. Husgärdessjön primarily receives water inflow through a canal from Skärvalången via Vagnsjön.

The water level in the lake system, including Husgärdessjön, is regulated at Ökulls kvarn south of Husgärdessjön. The outlet flows through Ökulls kvarn and further into a canal to the newly restored Spånnsjön, then continuing to Vingsjön, which eventually flows into Hornborgasjön. Eventually, the water from the Vallesjöarna lakes reaches Lake Vänern and the Göta River before flowing into the sea.

Husgärdessjön is also connected to the nearby Ökullasjön through a canal.

Nutrient-poor and alkaline.

The water in Husgärdessjön is clear, nutrient-poor (oligotrophic), while also having a high calcium content, high pH (pH>7), and an alkalinity value over 1.0. These unique characteristics provide favorable conditions for some plants that are sensitive to eutrophication and low pH levels. Several of the Vallesjöarna lakes also harbor species of plants and animals that are listed as endangered and threatened.

Bottom

The bottom of Husgärdessjön in deeper waters is composed of gravel and stones, but here near the camping site, the bottom consists of plateaus of so-called calcareous encrusted reed roots, forming a sort of mud-included limestone (chalk marl) on the sandstone.

Reed roots have formed a thick layer that extends a distance into the lake. It may be a bit soft to walk on, but for species like certain algae to thrive, shallow and clear water with direct sunlight exposure is required. In the past, the shoreline zone was kept free from reeds through grazing animals, but now we need to help keep the edge clear from reeds and other vegetation so that more species can be favored.

Piled jetty

Valle Camping has chosen to construct piled jetties. Pålade bryggor släpper ner mer ljus till livet under bryggorna. Floating jetties create large areas with shaded bottoms, which worsens the conditions for many animals and plants. Perhaps you may notice that some of the poles are slanted, and every year, it is a challenge to restore and adjust the jetties after the ravages of the ice.

Life in the lake

Plants

The Valle area has an exceptional and diverse flora. Here, we have selected some plants that you may encounter during your visit to Husgärdessjön at Valle Camping.

Charophytes (Stoneworts, Chara)

An example of a species that thrives in the nutrient-poor environment and clear water is benthic charophytes or stoneworts. Stoneworts are regularly built with candelabra-like whorls of branches at each node and long distances between each nodal branch. Stoneworts do not have roots; instead, they attach themselves to the substrate using transparent structures called rhizoids. When growing in calm, calcareous water like here in Husgärdessjön, a crust of calcium carbonate (CaCO3) forms on the stem and branches, resembling a type of coral. This process is known as encrustation. In English, the group of plants is called “stoneworts” or “stonewort algae.”

The crust of calcium carbonate makes the algae appear grayish and feel stiff to touch or walk on. Indeed, it may appear and feel like a lifeless plant, but that’s how it grows in calcareous lakes. Yes, it forms large mats or stone-like bushes that can cover the bottom of the lake. If the populations are exposed above the water surface, the plant and the calcareous material can dry out and form white mats on the water surface. Indeed, one could almost say that the calcareous encrusted stoneworts form Valle’s coral reefs :).

In Sweden, there are 34 species of stoneworts, of which 6 are considered threatened and listed in the Swedish Red List. Acidification and eutrophication are believed to be the reasons behind the species’ endangerment, although the situation for the species has improved. Conversely, one can say that charophytes are good indicators of a water body that is not suffering from eutrophication.

In Lake Husgärdessjön, during a survey, six different species of charophytes were found: Chara aspera, Chara globularis, Chara hispida, Chara papillosa, Chara tomentosa, and Chara virgata. At the dock, you probably see the spiked water-milfoil (Chara hispida). Today, all these species are considered to be viable or thriving.

Other plants in Husgärdessjön

Of course, there are plenty of other plants that you can find in and around the lake.

Plants that you can find right on the shoreline, in shallow water, or on land include water buttercup (Ranunculus lingua), celery-leaved buttercup (Ranunculus sceleratus), bittersweet nightshade (Solanum dulcamara), water plantain (Alisma plantago-aquatica), three-lobe beggarticks (Bidens tripartita), flowering rush (Butomus umbellatus), water hemlock (Cicuta virosa), gipsywort (Lycopus europeus), tufted loosestrife (Lysimachia thyrsiflora), purple loosestrife (Lythrum salicaria), whorled mint (Mentha x verticillata), water pepper (Persicaria hydropiper), small bur-reed (Sparganium emersum), and bladderwort (Utricularia sp.).

Some majestic plants that grow both along the shoreline and extend well above the water surface in large stands are common reed or bulrush (Phragmites australis), bulrush (Shoenoplectus lacustris), and narrow-leaved cattail (Typha angustifolia).

On the water surface outside the reed edges, you can find the yellow water lily (Nuphar lutea).

Beneath the clear water, various plants thrive, including hornwort (Ceratophyllum demersum), Canadian waterweed (Elodea canadensis), whorled water-milfoil (Myriophyllum verticillatum), spiked water-milfoil (Myriophyllum spicatum), shining pondweed (Potamogeton lucens), water moss (Fontinalis), and perfoliate pondweed (Potamogeton perfoliatus).

Invasive Species

Unfortunately, the cottage area that existed in the vicinity during the mid-1900s has led to the establishment of some invasive species in the area. We are currently working in various ways to eradicate them, but this effort will take a long time.

Animals

Mussels

Five species of freshwater mussels have been found in the Valle lakes. These mussels range from 5 to 15 cm in length (most are just under 10 cm, but some species can grow up to 20 cm).

They live at the bottom and are filter-feeders. Buried in the sediment, their posterior end faces upwards, and their siphons (breathing tubes) are open towards the water. Indeed, several of these mussel species can live for a relatively long time, and their annual shell growth allows us to determine their age, much like counting the rings on a tree. By examining the growth rings on the mussel shells, scientists can estimate the age of the mussels and gain valuable insights into their life history and the environmental conditions they have experienced over the years. This information is essential for understanding the population dynamics and conservation status of these mussels in the Vallesjöarna lakes and beyond.

The mussel population in Lake Husgärdes is substantial, and you can likely spot a few from the dock. During surveys, three species have been found: the common pond mussel (Anodonta anatina), the swollen river mussel (Unio tumidus), and the swan mussel (Anodonta cygnea).

The common pond mussel is recognizable by its 7-10 cm large rhombic to egg-shaped yellow to yellow-green shell with vivid green hues. It is almost always a hermaphrodite and requires host fish for its larvae.

Fish

In Husgärdessjön there are, among others, perch (Perca fluviatilis), pike (Esox lucius), bream (Abramis brama), roach (Rutilus rutilus), cormorant (Scardinius erythrophthalmus) and tench (Tinca tinca).

During the summer, you often see small perch swimming under the dock. They are recognized by their striped appearance and the red fins on their undersides. The species can reach up to 35 cm in length (with some records reaching up to 50 cm), but most are considerably smaller. The colors of perch vary depending on their living environment. Compared to relatives living in darker habitats, the perch in the lake are relatively light in color. You might already know that perch have black bands on their bodies, but did you know that no two perch have the same patterning?

Fishing in Lake Husgärdessjön

As you may know, neither hunting nor fishing is included in the right of public access. Fishing rights in Husgärdessjön are individual and held by the owners of the fishing rights. There are no fishing licenses available and the public is not allowed to fish in the lake. As a resident of the campsite, you can obtain permission to fish during your stay, subject to certain limitations and conditions. You can find more information about fishing in Lake Husgärdessjön here.

One of Sweden’s 95,700 lakes that are larger than one hectare (10,000 m2, 100×100 m)

Birds

The Valle area boasts rich birdlife, and Hornboga Lake is just a few kilometers away as the crow flies.

Mammals

If you take a nighttime dip and swim in the lake, you are likely to encounter some of the bats that live around the area. They often swoop by, hunting for insects on the water surface.

The Valle area is considered to have Sweden’s most diverse bat fauna north of Skåne. Bats are the most species-rich group of mammals in Sweden. With 19 bat species found here, constituting a quarter of all mammal species in the country (75 species). Over the years, 14 of these bat species have been identified in the Valle area through repeated recordings of bat ultrasonic calls at several locations in the area.

Some of the most common species found in Valle include the Daubenton’s bat (Myotis daubentonii), the soprano pipistrelle (Pipistrellus pygmaeus), the noctule bat (Nyctalus noctula), and the northern bat (Eptesicus nilssonii).

Other Animals

Apart from what we have mentioned, there are, of course, many other animals in and around the lake. These include a diverse insect fauna, amphibians, and crustaceans, as well as larger mammals that occasionally visit the lake, such as deer and moose. Foxes, badgers, and hares can also be found in the area. Additionally, beavers have made their home in the lake, and occasionally, smaller martens pay a visit to the lakeshore.

History

While this text has focused on life in the lake, don’t forget that Lake Husgärdes also holds a central place in Sweden’s history. You can find more information about it at www.axevallahus.se.