| Species name: | Hydrilla verticillata |
| Family: | Hydrocharitaceae |
| Group: | Angiosperms |
| Common names: | Grundnessel |
| Synonymes: | |
| Habitats: | Lakes, Watercourses |
| Time of introduction: | 1950 |
| Year of first report: | 1960 |
| Type of introduction: | Intentional |
| Distribution details: | |
| Donor area: | |
| Status: | Not established |
| Frequency: | Rare |
| Invasiveness: | Not known |
| Impact: | Not known |
| Comments: | |
| Last updated | 19-05-2009 (day-month-year) |
| Resources: | Google image search |
| References: |
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| Habitat | Explanation |
|---|---|
| Agricultural areas | Under cultivation |
| Arctic/alpine | Arctic/alpine vegetation types (latitude and altitude aspects involved) |
| Boreal forest | Conifer forest (Neddleleaf) |
| Coastland | Along and influenced by the sea |
| Continental ice | e.g. the glaciers on Greenland |
| Disturbed areas | Under human influence, but not under cultivation |
| Estuaries and brackish areas | Where freshwater meets the sea, and where salinity varies between 35 ppm and <5 ppm (such as the Baltic Sea) |
| Grass and heathlands | Dry grassland incl. steppe/prarie and heathland |
| Greenhouses or compost heaps | Here the climate is regulated to natural situation (temperature and humidity) |
| Host | Organism were the IAS gets protection or nourishment |
| Lakes | Freshwater bodies (stagnant, lentic waters) |
| Marine habitats | All saltwater habitats, benthic and pelagic (e.g. Atlantic, North Sea, Barents Sea) |
| Mixed conifer/broadleaf forest | Conifers (Neddleleaf) mixed with decidous trees |
| Not known | |
| Riparian zones | Along rivers |
| Rocks and lavafields | Rocky areas without natural vegetation or with very sparse vegetation |
| Shrublands | Shrubs and dwarfed trees |
| Temperate broadleaf forest | Decidous forests |
| Under human management | Inside houses and warehouses, inside furfarms, in closed aquacultural sites, in closed aquaria |
| Urban areas | Near human dvellings |
| Watercourses | Running water (lotic waters) |
| Vector | The bearer or carrier of pathogenic IAS |
| Wetlands | Bogs, mires and wet grasslands, lakeshores |
| Group | Explanation |
|---|---|
| Angiosperms | The other flowering plants - Angiospermophyta, classes Dicotyledoneae and Monocotyledoneae (Dicots and monocots) |
| Annelids | Lophotrochozoans: Annelida (Segmented Worms), Phoronida (horseshoe worms), Pogonophora (bearded tube worms), Sipuncula (peanut worms), Nemertini (ribbon worms), Echiura (Spoon worms), |
| Arthropods | Phylum Arthropoda (Spiders, Insects, Crabs, Crayfish etc.) |
| Birds | Not a big group in numbers, but one of the charismatic groups of vertebrates, Phylum Chordata |
| Bryophytes | Mosses and allies, such as liverworts |
| Cnidarians | Phylum Cnidaria (jellyfishes, corals, hydra, anemones) |
| Comb jellies | Phylum Ctenophora (comb jellies) |
| Coniferous plants | Gymnosperms - Coniferophyta/Pinophyta |
| Ferns | Pteridophyta (Ferns and allies) |
| Fish | An aquatic charismatic group, Phylum Chordata |
| Flatworms | Phylum Platyhelminthes (Flatworms) |
| Fungi | Macrofungi (incl. Lichens) |
| Macroalgae | Multicellular plants living in water (also called seaweeds) |
| Mammals | Not a big group in numbers, but one of the charismatic groups of vertebrates, Phylum Chordata |
| Microorganisms | Bacteria, vira, microfungi, diseases |
| Molluscs | Phylum Mollusca (Snails, Clams, Squid & Octopus) |
| Nematodes | The Ecdysozoan worms: Nematoda, Nematomorpha, Cephaloryncha, Onychophora |
| Other chordates | Urochordata (tunicates, sea squirts), Myxini (hagfish), Cephalochordata (lancelets) |
| Other invertebrates | Phylum Brachiopoda (Lamp Shells), Phylum Porifera (Sponges), Phylum Bryozoa ("Moss animals"), Phylum Rotifera (Rotifers) |
| Phytoplankton | Microscopic plants that live in water |
| Protozoans | Single-celled eukaryotic organisms |
| Reptilia & amphibia | Not big groups in numbers, but charismatic groups of vertebrates, Phylum Chordata |
| Sea urchins & starfish | Phylum Echinodermata (sea urchins & starfish, sea cucumbers) |
| Type of introduction | Explanation |
|---|---|
| Intentional | On purpose |
| Intentional & unintentional | Both the above ways |
| Not known | No information available |
| Unintentional | Unknowingly - as a by-product of human activities |
| Invasiveness | Explanation |
|---|---|
| Invasive | Threatens native biological diversity |
| Not invasive | Does not threaten native biological diversity |
| Not known | |
| Potentially invasive | Has a potential to threaten native biological diversity |
| Distribution | Explanation |
|---|---|
| Africa | |
| Antarctica | This is a continent where we will probably not see too many aliens species from |
| Arctic Ocean | Surrounding the north pole |
| Asia | Divides to Europa along Ural/Kazakstan, Black Sea |
| Europe | Divides to Asia along the Ural/Kazakstan (check maps for details) |
| Indian Ocean | South of India to the southern tips of Africa and Australia respectively |
| N. America | Canada, USA, Mexico |
| N. Atlantic Ocean | The upper part of the Atlantic, equator divides from the southern part |
| N. Pacific Ocean | Pacific Ocean the upper part, equator divides from the southern part. |
| Not known | |
| Oceania | Australia, New Zealand and small islands |
| S. America | All countries south of Mexico |
| S. Atlantic Ocean | The southern part of the Atlantic Ocean |
| S. Pacific Ocean | The lower part of the Pacific ocean |
| Southern Ocean | Ocean surrounding Antarctica and extends to 60 degrees latitude |
| Frequency | Explanation |
|---|---|
| Absent | Not found(primarily intended for phase II where we compare lists) |
| Common | Many sites in the country |
| Eradicated | Has been succesfully eradicated |
| Extinct | Has been successfully eradicated |
| Local | Locally abundant, many individuals in some areas of the country |
| Not known | |
| Rare | Few sites where it is found in the country |
| Very common | Many sites and many individuals |
| Pathway | Explanation |
|---|---|
| Agriculture | Plants for production of food for human and animal consumption, incl. crops and contaminants of hay, grain, fodder |
| Angling/sport | Live bait or dispersal via fishing gear or/and boats or as a consequence of aquasports |
| Animal husbandry | Animals for production of food for human, including the pest species introduced via the animal hosts |
| Aquaculture | Fish/crayfish/algae/seafood farming, or a consequences of stocking of species (pest species) - includes mariculture |
| Aquaria | Ponds and aquariums |
| Ballast water & sediments | Ballast water and sediments in tanks, as well as solid ballast, incl also the dispersal via shipping in general (eg. Brown rat) |
| Biological control | Introduced as a putative biocontrol agent/pest of another species |
| Escapes | Fur farming, pet-animals escaping from cativity, laboratory animals, animal escapes, pet trade |
| Fisheries | Commercial fishing |
| Forestry | Timber and tree production, including the pest species introduced via tree hosts or product thereof |
| Horticulture | Plants used for ornamental purposes, gardening |
| Hull fouling | Fouling of ships hulls |
| Hunting | Released as hunting quarry or prey |
| Landscaping | The use of plants in the landscape (such as hegde plantings, binding of silt, erosion control) |
| Medicinal | Typically plants (maybe a few animals) for this purpose |
| Not known | |
| Ornamental | Animals used for ornamental purposes auch as colourful slugs and birds in parks etc. |
| Reintroduction | Re-introduction of species that have died out in the country previously |
| Secondary introduction | Introduced species where populations have been introduced from a nearby country/sea area - not the natural distribution area |
| Transport | Infrastructure, translocation of machinery, transportation along roads and rails, planes, package material etc. |
| Status | Explanation |
|---|---|
| Established | The species has formed self-reproducing populations in semi-natural or natural areas. |
| In captivity/culture | Greenhouses, houses and otherwise confined by humans |
| Not established | The species has not formed self-reproducing populations (also called casual or incidental) |
| Not known | |
| Suspected | The species is suspected to be found in the country, but no scientific proof published |
| Within country transfer | The species occurs naturally (is indigenous) within one part of the country but has been introduced by humans into another region where it has not previously occurred. |
| Impact | Explanation |
|---|---|
| Abiotic changes | Modification of fire regime, succession, hydrology, nutrient availability, |
| Competition | Competing with other organisms filling the same niche in the food chain (horizontal effect), physical disturbance |
| Decomposition | Entering the local food web by being a new decomposer (vertical effects) |
| Disease transmission | Being a reservoir for parasites or a vector for pathogen or being a parasite/pathogen |
| Extinction | Extinction of native species - such a grave effect is rarely seen in our parts of the world (let's hope we se no records here) |
| Genetic | hybridising with a related species or varieties, may lead to extinction by gene flow or dilution of locally adapted genepool |
| Herbivory | Entering the local food web by being a new herbivore (vertical effects) |
| Human health | Human health effects by being toxic, causing diseases or allergies |
| None | Preferably (!) based on some kind of scientific knowledge |
| Not known | no information available |
| Predation | Entering the local food web by being a new predator (vertical effects) |
| Resource allocation | Being a new ressource for native or introduced species (for herbivores, predators or decomposers) (vertical effects) |
| Socio-economic | Fouling, clogging of waterways, leading to increased pesticide/herbicide use, control and management costs etc. |
| Toxic | Being toxic for local species, thereby displacing these. |