Mahonia aquifolium

Oregon Grape

The Oregon grape (Mahonia aquifolium) is an evergreen plant that is native to North America. It is often used as an ornamental plant in Europe and other parts of the world and has become invasive in some areas. The plant can reach a height of up to 2 metres and is characterised by its dark green, glossy leaves, which have thorny tips at the edges. They are similar in shape to those of the European holly (Ilex aquifolium). Mahonia aquifolium flowers from April to May with bright yellow flowers arranged in dense racemes at the end of the branches. The resulting fruits are small, blue-black berries that are often eaten by birds, which helps to spread the seeds.

Types of damage

Ecological damage

Mahonia aquifolium can suppress native plant species and alter the chemical properties of their soil environment. This can lead to a reduction in biodiversity, especially in dry forests, pine forests and mesophilic deciduous forests.

Economical damage

The Oregon grape can invade forestry areas and affect the growth and productivity of crops and disturb natural regeneration.

Region of origin

North America

Introduction vectors

Horticulture

The Oregon grape was often planted in gardens and parks as an ornamental tree

Dissemination by animals

Birds can eat the berries of the Oregon grape and excrete the seeds in other places. This allows them to be spread over greater distances
Current distribution

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

Miscellaneous

Family

The Berberidaceae family comprises about 14 genera with about 570 species. They are distributed worldwide, with a focus on the temperate zones of the northern hemisphere and South America. The family mainly includes shrubs, but occasionally also herbaceous plants and trees. Characteristic are the often prickly twigs and the radially symmetrical, usually six-petalled flowers. The fruits are usually berries or aggregate fruits. Well-known representatives are the barberries (Berberis), with some species as ornamental and medicinal plants, and barrenworts (Epimedium) as ornamental plants.

Climate change

Mahonia aquifolium 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 spread are soil type, rail infrastructure, road infrastructure, autumn precipitation and annual rainfall.

Positive effects

Parts of the Oregon grape can be used in pharmacology. For example, Ointments containing mahonia root extract are used to treat psoriasis.

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 Mahonia aquifolium 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.