Ben Christie sampling lagoonal invertebrates
FOLLOW-UP SURVEY ON TRUST’S NEW COASTAL LAND REVEALS IMPORTANT INVERTEBRATES
Our follow-up survey on Norfolk Wildlife Trust’s new marsh at Cley has found five invertebrate species of conservation importance, including lagoon sand shrimp Gammarus insensibilis (legally protected) and mud snail Ecrobia ventrosa.
The Trust commissioned a specialist baseline study on their new land at Cley Marshes when they purchased it in 2014. This was surveying the plants and invertebrates in the site’s ditches, dykes and scrapes.
Since then, the Trust has carried out extensive work on the marsh to convert it from wildfowling ponds to a nature reserve and wanted to repeat the surveys. The plan was to compare with the 2014 baseline and identify any changes resulting from the work.
Twelve sample ditches and lagoons sites from the 2014 survey were re-surveyed for aquatic invertebrates, following the same methodology. For each, we took two dip-net samples to collect a crosssection of the aquatic invertebrates in the water: one in underwater vegetation near the shore; and one reaching out into the depths of the open water.
Ben Christie, our invert specialist said: “By first grouping inverts into taxonomic orders and then using specialist microscope keys for identification, we were able to efficiently identify the specialist communities for every sample site. This allowed both a direct comparison of communities in 2014 and 17, but also showed distributions for five invertebrate species of conservation importance.
“Norfolk Wildlife Trust can now fully assess the benefits of their management on invertebrates as well as the birds and other wildlife who are dependent on them in the food chain.”
With support from members, business and the Heritage Lottery Fund, Norfolk Wildlife Trust acquired 60 hectares of land at NWT Cley Marshes in 2014. Norfolk Wildlife Services carried out baseline studies of the plants and invertebrates with particular focus on the impacts of the January 2014 flooding on the site’s ecology.
We decided to get stuck into the project (literally) to survey the saline lagoons and freshwater dykes across the site for aquatic plants such as Phragmites australis, and aquatic invertebrates such as the water boatman Arctocorisa garmari. Initial results showed that an increased proportion of the open water on the site was unsurprisingly either brackish or saline. The effect on invertebrate species was evident during surveying as several groups were under-represented such as dragonflies.
In early summer 2015, we will survey the terrestrial invertebrates when they are most active. Some of the terrestrial invertebrates sought for include the Red Data Book ground beetle Pogonus luridipennis, or more commonly found cross spider Araneus diadematus. Invertebrates like these are key indicators of the habitat quality and conditions present.
NWS will be running a workshop in September next year, looking at how the invertebrate population at Cley supports birds such as bittern, avocet and godwit. Check our website for more details on this “Bittern’s Breakfast and Avocets Lunch” event.
We are a wholly-owned subsidiary of Norfolk Wildlife Trust, one of the largest and oldest Wildlife Trusts in the country. All of our profits are donated back to NWT, directly benefiting the county’s wildlife and wild habitats. For more information about Norfolk Wildife Trust see their website at http://www.norfolkwildlifetrust.org.uk
Wildlife Trust environmental consultancies offer professional expertise throughout the country in ecology, landscape and planning. Profits go to their parent bodies, conservation charities with the collective aim of protecting wildlife for the future. The Association promotes quality standards. Its members share training and knowledge and work together on major and national projects.
Norfolk Wildlife Services is one of 22 members of the Association of Wildlife Trust Consultancies. If you need an ecological consultant elsewhere in England, Wales or Scotland then visit the AWTC website for further details of a Wildlife Trust Consultancy in your area.
Please keep an eye on the NWT website at www.norfolkwildlifetrust.org.uk/jobs