Lagarosiphon major

Curly Waterweed

Lagarosiphon major is a submerged aquatic plant that originates from South Africa. The plant can grow up to 5 metres long and forms dense mats on the water surface. L. major is characterised by its dense, spirally arranged leaves, which are around 1 cm long and pointed. The plant rarely flowers and when it does, it is usually only on the water surface. The flowers are small and white, with the female flowers remaining on the plant and the male flowers drifting off at the surface. Reproduction is primarily vegetative, with individual plant parts breaking off to form new plants. It prefers stagnant and slow-flowing waters and is tolerant of changing environmental conditions, including different water temperatures and qualities. In Europe and other parts of the world where it has been introduced, it can spread rapidly and quickly forms large carpets on the water surface, competing with native aquatic plants and disturbing the ecological balance of water bodies.

Types of damage

Ecological damage

Due to its rapid reproduction and spread, Lagarosiphon major can dominate aquatic habitats and suppress native aquatic flora, leading to a reduction in biodiversity. In addition, its dense growth can block the light necessary for the growth of other aquatic organisms, thus disrupting the entire ecosystem of the water body.

Economical damage

Lagarosiphon major can block waterways, disrupting water traffic and transport. In addition, it can interfere with recreational use of water bodies such as fishing, swimming and boating. The costs of controlling and eradicating this invasive species can be significant.

Region of origin

Southern Africa

Introduction vectors

Horticulture

Although Lagarosiphon major is mainly traded as an aquatic plant, it can also be accidentally spread with other garden plants when garden waste containing remnants of the plant is disposed of near waterways.

Pet trade (aquaristics)

Lagarosiphon major is a popular aquatic plant and was often bought for aquariums and garden ponds in the past. From there it could enter the environment when the aquarium or pond was cleaned or drained and remnants of the plant got into nearby waterways
Current distribution

Based on the FlorKart Database of the Federal Agency for Nature Conservation, as of 2013

Miscellaneous

Family

The Hydrocharitaceae comprise about 16 genera with about 135 species. They are distributed worldwide and represent the largest family of fully aquatic flowering plants. The family includes both free-floating and bottom-anchored species, which can often form dense stands. Characteristic features are the mostly simple, often linear leaves and the often small, inconspicuous flowers. Many species are important for the ecosystem of freshwaters, but some can also cause problems as invasive plants. Well-known representatives are the hornwort (Ceratophyllum), or the waterweed (Elodea), which are used as aquarium plants.

Climate change

Lagarosiphon major has not yet filled its potentially suitable habitat under current climate conditions. It does not benefit from climate change because in the future its potentially suitable habitat will become smaller. The environmental factors that most influence its dispersal are waterways, soil type, land use type, altitude and annual temperature.

Dispersion forecast

Indicates the proportion of land suitable for habitat under current and future climate conditions (2060-2080) under three emission scenarios (RCP26, RCP45 & RCP85).

Habitat suitability maps

Instructions for use: Click here

Habitat suitability under current climate conditions

These habitat suitability maps show for Lagarosiphon major where suitable habitat conditions exist.

The map on the left shows this for current climate conditions. Below this are maps for the time classes 2040-2060 and 2061-2080, in which three different emission scenarios can be selected.

The slider at the top left allows you to adjust the opacity of the map to make orientation easier.

By clicking on the respective quadrant, information on the environmental conditions present in it can be called up.

The methodology is explained here .

Habitat suitability 2040 - 2060

2040-2060: In the RCP2.6 scenario, GHG emissions are expected to peak by 2040 through comprehensive mitigation measures and to decline rapidly thereafter. By 2060, global warming would stabilise at about 1.5°C above pre-industrial levels. Subtle changes in precipitation patterns could vary regionally, with some areas facing increased drought and others increased precipitation.

2040-2060: Under RCP4.5, GHG emissions would continue to increase until 2040, but stabilise at a high level thereafter. By 2060, there could be a global temperature increase of about 2°C above pre-industrial levels. This scenario would likely cause moderate changes in precipitation patterns, with potential regional differences.

2040-2060: Under RCP8.5, which assumes continued intensive use of fossil fuels, greenhouse gas emissions would rise sharply by 2060. The global temperature increase could be around 2.5-3°C. In this scenario, significant changes in precipitation patterns could occur, with an increased likelihood of extreme weather events.

Habitat suitability 2061 - 2080

2060-2080: By 2080, global warming could be limited to below 2°C in the RCP2.6 scenario, provided emission reductions are consistently pursued. Impacts on precipitation patterns would likely stabilise, although regional variance would remain significant.

2060-2080: In the RCP4.5 scenario, global temperatures would continue to increase and could be around 2.5°C above pre-industrial levels by 2080. Changes in precipitation patterns would likely increase and regional differences could become more pronounced.

2060-2080: Under RCP8.5, global temperatures could rise by more than 4°C above pre-industrial levels by 2080. Precipitation patterns would be expected to change significantly, with further increases in the frequency and intensity of extreme weather events. This would have far-reaching impacts on ecological and socio-economic systems.