NNNSI "Pond Invaders" Invasive Alien Species Survey

Ponds are great! They create a fantastic garden feature and can be filled with an abundance of wildlife species. However, some ponds hold a less desirable inhabitant… Sadly invasive aquatic plants have been widely stocked in garden ponds for a number of years, and the plants present in these ponds now present a real threat to our native biodiversity in the wild.

The spread of these species is largely fuelled by the unknowing actions of pond owners, gardeners and anglers. Once in the wild these plants rapidly take over their new habitat, and can be costly to remove (just three invasive aquatic plant species cost more than £3m a year to control in GB).

The Pond Invaders survey aims to tackle the impact of some of the worst invasive species that are found in ponds. YOU can help by telling us when you see them. Without accurate and up-to-date information on the distribution of these species, we cannot control them effectively.

THE POND INVADERS SURVEY SPECIES ARE:

Water fern (Azolla filiculoides)
New Zealand Pigmyweed/Australian Swamp-stonecrop (Crassula helmsii)
Parrot's feather (Myriophyllum aquaticum)
Floating pennywort (Hydrocotyle ranunculoides)
Creeping Water-primrose (Ludwigia peploides)

 

IF YOU HAVE SEEN ANY OF THESE 5 NON-NATIVE SPECIES PLEASE USE OUR ONLINE RECORDING FORM (LINKS BELOW) TO TELL US ABOUT YOUR SIGHTING(S).

FOR MORE INFORMATION ON EACH OF THESE SPECIES SEE DETAILS BELOW THE ONLINE RECORDING FORM LINKS.



HAVE YOU SPOTTED ANY OF THESE 5 NON-NATIVE SPECIES?

 

The easiest way to send us information about the species you have seen is via our online form. Please select one of the three options below to send us your record(s):


 


 

(e.g. more than 20 records; including records of more than one species,
at more than one location and on several different dates 
- please send as excel spreadsheet where possible using our template)

DOWNLOAD THE NBIS RECORDING SPREADSHEET HERE AND THEN CLICK ABOVE TO EMAIL US YOUR RECORDS
 (or email nbis@norfolk.gov.uk)
 



 

....SOME BASIC INFORMATION:

 

Water fern (Azolla filiculoides)

Description: A small free-floating plant which forms dense mats of vegetation on the surface of a water body. Each plant is 2.5cm long with a fern-like appearance, and non-wettable leaves. It is usually green but often has a reddish tinge.
When was it introduced? Originating from the Americas, it was first recorded in England in 1883 and has spread rapidly over the last 50 years.
How does it spread? Vegetative fragmentation and through spores.

 

 

New Zealand Pigmyweed/Australian Swamp-stonecrop (Crassula helmsii)

Description: A hardy plant which can grow in and out of water. It is particularly easy to spot when growing at the edge of a pond where its characteristic narrow and fleshy leaves are clearly visible. When submerged, the plant has more elongated stems, with flatter leaves. Leaves lack a notch at the tip (unlike native waterstarwort).
When was it introduced? First introduced to the UK in 1911 as an oxygenating pond plant.
How does it spread? Spreads by vegetative fragmentation.

 

Parrot's feather (Myriophyllum aquaticum)

Description: Feather-like leaves with a blue-green colour. Usually produces significant growth above the pond surface, but can also be submerged. The stems are brittle which means it is not usually found in fast flowing water.
When was it introduced? Grown in water gardens in the UK since 1878. First recorded in the wild in 1960.
How does it spread? Vegetative fragmentation.

 

 

Floating pennywort (Hydrocotyle ranunculoides)

Description: This aquatic plant has characteristic, kidney-shaped leaves which can be free-floating or emergent. It has fleshy stems and fine, white roots. Floating pennywort can rapidly dominate a water body.
When was it introduced? A recent introduction, this plant was first found growing in the wild in 1990.
How does it spread? Vegetative fragmentation (does not produce viable seed in the
UK).

 

Creeping Water-primrose (Ludwigia peploides)

Description: This plant has a distinctive floating form and is easiest to identify when in flower (July— August). The large yellow flowers have five petals.
When was it introduced? This plant is uncommon in the UK, occurring at less than 20 known sites. It was first found in the wild in 1999.
How does it spread? Vegetative fragmentation and seed.

 

 

 

We have created a dedicated FAQs page and advisory service to support the Pond Invaders campaign.
Find out more: www.norfolkbiodiversity.org/nonnativespecies