Amaranthus retroflexus

Red-root Amaranth

The Red-root Amaranth (Amaranthus retroflexus) is an annual plant that originates from North and Central America, but is now found in many parts of the world. It is characterised by its upright growth habit and a height of up to 1.5 metres. The leaves of the Red-root Amaranth are oval, pointed at the end and alternate. They can sometimes have a reddish-purple tinge. The plant produces dense, erect inflorescences that contain small, inconspicuous flowers. After pollination, tiny, black seeds develop and are produced in large quantities. Amaranthus retroflexus is known for its adaptability to different soils and locations and can grow in agricultural land, gardens, wasteland and other disturbed areas.

Types of damage

Ecological damage

Amaranthus retroflexus can spread rapidly and suppress native plant species. Due to its ability to produce large quantities of seeds that have a high germination capacity, it can occupy ecological niches and affect the diversity and structure of native plant communities

Economical damage

In agricultural areas, Amaranthus retroflexus can lead to considerable yield losses, as the plant spreads on arable sites and is extremely competitive. As a late germinator, it is often no longer detected by soil herbicides, which leads to higher control costs.

Region of origin

North America

Introduction vectors

Agriculture

Contaminated seeds of agricultural crops

Dissemination by animals

Amaranthus retroflexus produces a large quantity of seeds that can be transported over long distances, for example by the wind or by birds.

Current distribution

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

Miscellaneous

Family

The Amaranthaceae family comprises about 174 genera with about 2360 species. They are distributed worldwide, mainly in tropical to subtropical areas. This family contains annual and perennial herbaceous plants, semishrubs, shrubs and trees. Some species are succulent. The leaves are usually entire and the flowers often small but grouped in showy, often richly branched inflorescences. Important representatives are amaranth, quinoa and beetroot, which are used as food plants, as well as the ornamental plants woolflower and bloodleaf.

Climate change

Amaranthus retroflexus has already filled its potentially suitable habitat under current climate conditions. However, it benefits from climate change because in the future its potentially suitable habitat will become larger. The environmental factors that most influence its spread are precipitation in autumn, soil type, temperature in summer, road infrastructure and altitude.

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 Amaranthus retroflexus 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 beschrieben.

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.