Cactus moss

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Cactus moss
Cactus moss (Campylopus introflexus)

Cactus moss ( Campylopus introflexus )

Systematics
Class : Bryopsida
Subclass : Dicranidae
Order : Dicranales
Family : Leucobryaceae
Genre : Campylopus
Type : Cactus moss
Scientific name
Campylopus introflexus
( Hedw. ) Brid.

The cactus moss ( Campylopus introflexus ), also known as long-haired or hair- wearing scimitar moss , is a deciduous moss from the Leucobryaceae family .

The moss originally comes from the subtropical to cold-temperate latitudes of the southern hemisphere. It has been introduced in North America and Europe. The so-called invasive neophyte proves on the colonization especially the coastal dunes and other sandy habitats, especially in the Netherlands, Belgium and Germany as problematic as the moss species compositions and the appearance of the characteristic there communities changed. Significant changes in the ecosystem are ascribed to the cactus moss due to the formation of dense and large mats.

Taxonomy

The moss species was first described by Johannes Hedwig as Dicranum introflexum . Further synonyms given in the literature are: C. polytrichoides auct. pp and C. lepidophyllus ( C.Muell. ) Par. fide sim. In the early years of the discovery of the cactus moss in Germany and North America, C. introflexus was used for the species known as C. pilifer due to confusion . This means that older work on C. introflexus refers to C. pilifer . Only later did it emerge that it was the Dicranum introflexum, which is widespread in the southern hemisphere, or moss, which is now known as C. introflexus .

Characteristics and biology

Cactus moss ( Campylopus introflexus ) with sporogons
Cactus moss ( Campylopus introflexus ), close-up with glass hair

The acrocarpic cactus moss grows in dense, light to olive green, often grayish and up to 5 centimeters high mats and extensive moss carpets. The stems are between 0.5 and 5 centimeters high. The lanceolate and entire-edged leaflets measure 4 to 6 millimeters in length. They are transparent at the leaf base. The leaf vein is wide and takes up about half the leaf width. There are two-cell lamellae on the back of the leaf vein. On the underside of the leaf vein there are chlorophyllous, water-white hyalocytes . Especially in the upper trunk area, these run out at the tip into a strikingly right-angled bent glass hair . When wet, the leaflets stick out from the stem. When dry, on the other hand, they are close-fitting and form white stars when viewed from above due to the whitish-transparent, protruding glass hairs. Plants grown in wet periods only form glass hairs on the lower leaves. The capsules are brown and 1.5 millimeters long. Its 7 to 12 millimeter long, yellowish to brown stem is growing straight. Usually several sporophytes are formed on a plant.

Habitats

In the southern hemisphere, Campylopus introflexus grows on diverse substrates from sea level to heights of 200 meters. In North America and Europe it is a pioneer colonizer of open, near-natural and anthropogenic locations with dry and acidic soils. The moss predominantly colonizes stone and sandy soils and penetrates the silver grass fields of the coastal and inland dunes , into dwarf shrub heaths and lichen-pine forests . It also colonizes open sand areas in post-mining landscapes . In the UK, however, it grows on peaty soil moist heaths and peat disturbed and burning Moore . It grows on lime-free, long-term dry, poor mineral and humus soils in mostly sunny locations. It colonizes rotten wood less often.

Distribution and ways of propagation

original distribution area in black, new populations in red

The original distribution area of ​​the cactus moss is the southern hemisphere. There it occurs in South America, Africa, Australia and the Pacific islands up to cold-temperate climates. It has been introduced in North America and Europe. In North America, it mainly populates the west coast of the USA and Canada. In Europe it was first detected in England in 1941. From there it has spread over large parts of Europe. Today it is present from Iceland to Spain, from Ireland to Poland. In France it was found in 1959 at Cape Finisterre . It has settled in the Netherlands since 1961, in Belgium since 1966, in Denmark since 1968, in the Faroe Islands since 1973 , in southern Sweden since 1976, in western Norway since 1978 and in Iceland since 1983. The moss was first detected in Poland in 1986 and in the Carpathian Mountains in 1994. In the year 2000 the first proofs for Russia and Latvia were received.

In Germany, the cactus moss was first detected in 1967 near Münster (Westphalia). It is said to have immigrated via the Netherlands. It has been found on the East Frisian Islands since 1970 . In Germany, with a focus on the west, moss is widespread in all federal states with a continuing tendency to spread and has developed established populations in many places. The years of the first finds on the East Frisian Islands are given as follows: 1970 on Langeoog , 1975 on Baltrum , 1976 on Spiekeroog , 1977 on Norderney and 1980 on Borkum , Juist and Wangerooge . In 1985 the moss was first found on the Attersee in Upper Austria .

On the one hand, it spreads through asexual reproduction through broken stem tips. New plants can develop from these. Whole moss cushions can also be carried by wind, animals (rabbits, birds) and people and colonize new, self-isolated and distant locations. The regeneration-happy shoot tips are mostly formed in young stands, so that they grow very quickly. They can cover several hundred square meters within ten years. If sporogons are formed, they produce numerous spores between 10 and 14 µm in size, which can be spread over long distances. The formation of sporogons can only rarely be observed in Germany. The colonization of the Faroe Islands before the colonization of Norway is seen as a sign of the high generative dispersal of moss.

Status and invasiveness

In Austria, the moss is expected to spread further. While the cactus moss is absent-minded in most European countries and is considered to be unproblematic, the moss has spread strongly in the Netherlands and Belgium in the past 20 years and is considered to be a source of danger for other mosses and lichens. It is referred to here as "tankmos" because it is said to have been spread with tanks during World War II . In Germany, too, moss is classified as problematic and is considered an invasive neophyte. On the East Frisian Islands in particular, it invades the moss and lichen-rich stages of the dry sand grassland of the gray dunes. In the brown dunes it settles in gaps of crowberry and broom heather. Sometimes the moss covers grow up to 10 centimeters high and even form dry cracks when it is dry. Heavily populated silver grass meadows are sometimes classified as a separate plant sociological society , the Campylopus introflexus society.

Environmental impact

The enormous spreading power on the generative and especially the vegetative way makes the spread of the cactus moss questionable. The dominant populations of the cactus moss arise either from the colonization of open areas or from the displacement of other, previously mostly population- forming species such as Dicranum scoparium , Politrichum juniperum or P. piliferum . In silver grass meadows, the numbers of most characteristic species decrease and the appearance of the biotope changes. Finally, closed mats of moss are formed, which lie like a "shroud" over the gray dunes. In addition to the vascular plants, the mosses and lichens ( Cladonia species) that are characteristic of silver grasslands are being displaced. The moss carpets can crack when it is dry and are turned over by animals, which in turn creates open spaces. These are usually closed quickly by the cactus moss. It is unknown whether other plants or the original vegetation can establish themselves in these gaps. The displacement of the typical dune vegetation, which due to its rarity and sensitivity belongs to the habitats of the Fauna-Flora-Habitat Directive worthy of protection, contributes significantly to a decrease in biodiversity and the endangerment of a number of mostly rare species. In Küstenheiden Denmark dense stands reducing the moss regeneration of the heather ( Calluna vulgaris ), which is associated with the reduction of the germination of the seeds due to lack of light and dryness in the dense moss carpets.

It is believed that the change in habitats could be a cause of the decline of the Bracheeper ( Anthus campestris ). This is associated with a reduction in arthropods as a source of food and the loss of suitable breeding grounds in the dunes dominated by cactus moss. Other effects of the spread of Campylopus introflexus on wildlife are not yet known.

After all, the moss stands several centimeters high have, in different ways, a considerable influence on the site conditions and thus on the ecosystems in terms of water balance and succession . The dark moss cushions heat up faster than the adjacent light sand areas, which leads to a greater drying out of the sand habitats. On the other hand, the moss cushions and carpets also store more water. It is still unclear whether this will result in a more balanced water balance in the ecosystems. The colonization of sand habitats with cactus moss accelerates the natural succession of the vegetation insofar as the sands are fixed by the moss and plants such as common heather and wire smear ( Deschampsia flexuosa ) are able to settle here. It is not yet known how accelerated succession will affect ecosystem dynamics.

Sources and further information

Individual evidence

  1. ↑ a b Richard Pott : Color Atlas North Sea Coast and North Sea Islands. Selected examples from the southern North Sea from a geobotanical perspective. Ulmer, Stuttgart 1995, ISBN 3-8001-3350-4 .
  2. ^ A b Franz Essl, Wolfgang Rabitsch: Neobiota in Austria. Federal Environment Agency, Vienna 2002, ISBN 3-85457-658-7 digital version (PDF; 4.12 MB).
  3. ↑ Thilo Hasse: Vegetation studies in a lichen-rich inland dune landscape in the De Hoge Veluwe National Park (NL) - statement on a planned reactivation of the sand drift. Münster 2002, (Münster Westphalian Wilhelms University, diploma thesis, 2002).

literature

Web links

Commons : Cactus moss ( Campylopus introflexus )  - album with pictures, videos and audio files