Neophytes are often portrayed as dangerous and hostile. But only very few species have negative consequences for our ecosystems. These species not only shape nature but also cultural landscapes. Alternative ways to deal with this potential danger are therefore not entirely new.
What are neophytes and are they dangerous?
Neophytes are plants that are not part of the natural vegetation of a habitat and have been spread worldwide by humans. Only a few neophyte species that are considered invasive have negative impacts on native ecosystems. Most neophytes can exist peacefully alongside native plants and often enrich our cultural landscapes.
What are neophytes?
Neophytes are a subcategory of neobiota. This term is derived from the Greek terms néos for “new” and bíos for “life”. In the strict definition, neobiota includes all species that have been spread throughout the world by humans. These creatures spread into foreign areas where they were not previously considered native. Few naturalists are of the opinion that other species that spread into foreign areas without human intervention also fall under the neobiota.
The term Neobiota includes:
- Neophytes: neobiotic plants
- Neozoa: neobiotic animals
- Neomycetes: neobiotic fungi
A look into history
So-called new plants are not an unknown phenomenon. It is a natural process that new species are constantly immigrating to Central Europe. The entire vegetation of Central Europe is characterized by species that have migrated since the Ice Age. The ecosystems in Germany and Europe have developed a high level of resistance to newly immigrated species.
There are many niche habitats in which alien species find a place and thrive alongside native plants. This development is promoted by climate change, because due to global warming, heat-loving plants and animals are increasingly spreading to northern regions.
Neophytes in Germany before and after 1492
During the Neolithic period, people carried away numerous wild herbs when they imported grain. Today many of these herbs are on the Red List of Endangered Species. These plants, which came to Europe through Neolithic humans or Roman trade, are called archaeophytes. It was only since Columbus discovered America in 1492 that the global movement of goods and people, and thus the movement of plants, increased. All plants introduced after this year are called neophytes.
Current situation
Almost half of all neophytes that have established themselves in Germany were introduced intentionally. Of this amount, 30 percent are ornamental plants. The remaining 20 percent are agricultural and forestry crops such as corn, potatoes and tomatoes. The other half of the new plants were introduced unintentionally, for example as an unwanted addition to the seeds.
When combating alien species makes sense:
- Remaining occurrences of endangered species are being displaced
- when there are risks of hybrid formation between alien and native species
- historical authenticity of the species in a cultural landscape is endangered
Invasive neophytes in Germany
Japanese knotweed is an introduced plant in Germany
Not all organisms that do not belong to native nature are undesirable or dangerous. There are few newcomers who can establish and spread independently in a foreign climate. The so-called rule of ten states that only ten percent of all introduced species can survive in the new habitat. The remaining 90 percent disappear after a short time. A further ten percent of the new species can establish themselves and ten percent of these lead to negative effects. These plants are called invasive neophytes.
At around 0.2 percent, the proportion of invasive plants - measured against all neophytes - is negligible.
Definition
While the neobiotic species only include organisms that have been introduced into foreign areas, the attribute “invasive” refers to animals, plants and fungi that have firmly established themselves in their new habitat. They pose a danger to the local flora and fauna because they have a strong influence on the species composition and can displace animals or plants.
Excursus
What financial damage do neophytes and neozoa cause?
Gray squirrels, raccoons and giant hogweed are considered alien species in Germany that have now successfully established themselves. Such a spread of non-native species can come at the expense of the new homeland if it displaces species with weak competition and loses habitats. Invasive species can be a major threat to native biodiversity and cause economic damage. According to an estimate by the EU Commission from 2018, these creatures are said to have caused damage worth twelve billion euros across Europe.
Why are invasive neophytes so competitive?
The requirements of these plants match the conditions in the new habitat particularly well. You can fill a previously unfilled gap there. Many neophytes have no predators in foreign areas, which means that nothing stands in the way of their spread. In Germany, neophytes are increasingly growing on disturbed and nutrient-rich sites such as roadsides and farmland. In contrast, forests or moors are rarely populated by newcomers. This suggests that these plants are adapted to nutrient-rich locations and are tolerant to disturbances.
Characteristics that support spread:
- Plants produce large quantities of seeds
- their ability to spread vegetatively is very high
- high adaptability to new environmental conditions
Neophytes: examples of alien plants
The beautiful balsam is a master at throwing seeds
The list of neophytes in Germany includes around 400 plants. This neophyte list contains established plant species, some subspecies and varieties as well as new species that have arisen through crossings and vegetative propagation. In 2019, the EU published the Union List, which lists 66 invasive animal and plant species. Of these creatures, a handful of species are considered to pose a major threat to biological diversity due to their biology.
| scientific | Origin | Problem | |
|---|---|---|---|
| Hercules Plant | Heracleum mantegazzianum | Caucasus | produces up to 10,000 seeds |
| Japanese knotweed | Fallopia japonica | East Asia | explosive spread over extensive root shoots |
| Glandular Balsam | Impatiens glandulifera | Himalayas | shoots seeds up to seven meters |
| Canadian Goldenrod | Solidago canadensis | North America | forms impenetrable thickets |
Lupine (Lupinus polyphyllus)
The species, originally from America, is characterized by a long taproot. One plant develops up to 60 flowers. These develop around 2,000 seeds that can be thrown over a distance of six meters. There are nodule bacteria on these roots that bind atmospheric nitrogen and make it available to plants. As a result of their spread, soils become more fertile, which is not desirable everywhere. The lupine also spreads in poor soils and displaces species that depend on such locations.
Threatened Species:
- Arnica and cat paws
- Bristgrass and globeflower
- Orchid and Turkish lily
Mugwort ragweed (Ambrosia artemisiifolia)
The ragweed is a thorn in the side of allergy sufferers
In Bavaria, ragweed is becoming increasingly widespread. The species was able to spread unnoticed through bird food and mainly grows in gardens under bird feeders. As a ruderal plant, the species, which comes from North America, colonizes disturbed sites and roadsides. It grows on railway embankments, on rubble heaps and construction sites. Since the pollen can cause severe allergies, the Bavarian Ministry of the Environment has developed an action program to combat the species.
Robinia (Robinia pseudacacia)
The tree comes from North America and is planted in avenues under the name Silberregen. The special properties of this species become apparent in rubble dumps: it is resistant to road s alt and tolerates emissions. The robinia currently has the greatest displacement potential. It is able to bind atmospheric nitrogen and accumulate it in the soil. Since the woody plant spreads in poor locations, it causes such areas to be over-fertilized. Protected and specialized species are being pushed out of these habitats.
This is what robinias cause:
- species-rich semi-dry lawns are shaded
- rare orchids are lost
- Insects that specialize in orchids cannot find food sources
- damp embankments are loosened and softened by foothills
- Nitrogen accumulated in the soil is washed into the water bodies
Does the individual have to do something?
As beautiful as some neophytes are, they tend to crowd out native species
It is primarily a matter of nature conservation to decide on control measures. There are still large gaps in invasiveness assessment. Many connections within the spread of such species are unknown. An individual's good will can quickly lead to negative consequences. Mixtures and carelessness can also damage native and endangered species. Every clearing action represents another intervention that can disrupt breeding birds or create a gateway for new species.
Tip
Make sure that you choose the plants in your garden carefully and, if possible, do not plant plants that tend to spread.
Prevent spread
If the populations have already expanded to such an extent that complete clearing seems unrealistic, further spread should be controlled. Make sure lupins and goldenrods do not reproduce from seeds. Cut off the inflorescences in good time before seeds form. Continuously removing new shoots helps prevent vegetative spread.
Using neophytes in the kitchen
Many neophytes such as potatoes, Jerusalem artichokes and tomatoes have now become an integral part of the kitchen. Even among the plants naturalized after 1492 there are herbs that are edible. If the species do not threaten the habitat, comprehensive control makes little sense. Rather, you can harvest seeds, leaves or shoots of these plants and keep their spread under control through targeted collection campaigns.
Neophyten Seminar
Tip
Look carefully at pictures of native and alien species before you go collecting. Many species look very similar.
Japanese knotweed
The plant is considered a medicinal herb in China and Japan and is used for healing teas. Their young shoots taste similar to the leaf stalks of rhubarb. They can be processed into tasty dips and tangy jams. If they are very young, the shoots can be eaten raw.
Lupine
The seeds of the lupine are a relatively unknown ingredient in dishes. Their nutritional content is comparable to that of related legumes such as peas and soybeans. Before the seeds can be consumed, the bitter substances must be removed. In traditional processes, this is done by storing it in s alt water for 14 days. The seeds are then boiled several times in fresh water. Lupine seeds can be prepared as a pea vegetable or used in salads.
Frequently asked questions
What are alien species, neophytes and neozoa?
In Germany and neighboring German-speaking countries, plants are usually referred to as neophytes and animals as neozoans. In English usage, a division into plants, animals and fungi is unusual. Non-native species are collectively referred to as “alien species”. If the species have a displacing character, they are considered “invasive species”.
How dangerous are neophytes?
There are some species that pose he alth risks to humans. However, not everyone reacts the same way. Sensitive people and allergy sufferers should exercise caution. Giant hogweed produces a substance that destroys the skin's natural sun protection when touched. Severe burns and blistering can occur under normal sunlight.
The ragweed produces billions of tiny pollens until November, which penetrate the respiratory tract and trigger allergies. The narrow-leaved ragwort likes to settle in pastures and fields. If their poisonous plant parts get into the grain harvest, they can affect he alth when eating bread.
Can neophytes be useful?
Neophytes play an even more important role the more remote a location appears from nature. Due to their location requirements, some plants may be more suitable as native plants when it comes to colonizing severely degraded areas. Neophytes are now considered important food plants for many animals:
- Copper rock pear provides food for birds
- late-flowering giant hogweed provides food for bees when hardly any other plants are blooming
- Glandular balsam is one of the most visited flowering plants among bumblebees in August
- Horse chestnut leafminer is an important food source for tits while rearing young
Why are neophytes spreading so much?
Plants live in a constantly changing world in which living conditions also continually fluctuate. This leads to poorly adapted species being pushed out and better adapted creatures finding a new niche. Such processes also take place independently of human intervention. But many species cannot access these habitats without transport by humans.
Do neophytes need to be combated?
It requires a critical look at whether a species actually needs to be eradicated again. Such a measure represents further human intervention, which in turn can provide a gateway for new undesirable species. It is only because of humans that places are created where highly specialized and endangered native species cannot find a basis for life. If a non-native species happens to arrive at this location, it can exploit its growth advantage. Alternative measures such as control or use appear to make more sense in modern nature conservation concepts.
