Courtney Brain

A successful first delivery season for the T&I INNS Project

The Test and Itchen Invasive Non Native Species Project only began in July of last year (2021), which made it hard to take action against invasives with only weeks remaining of the delivery season. So the 2022 Delivery Season was the first full delivery season for this project and it went swimmingly!

We started our season by celebrating Invasive Species Week 2022 in May. Invasive Species Week is a national series of events hosted around the UK, largely co-ordinated by the GB Non Native Species Secretariat, to raise awareness on the harm invasive species are having on our native ecosystems. In honour of Invasive Species Week we ran a volunteer INNS training event, arming our INNS Volunteers with the skills to identify the priority target species for this project so they were equipped to join us for riverbank surveys later in the season. Later in the week we successfully removed large amounts of Himalayan balsam on the lower banks of the River Itchen, we even had Alex and Dave from the team joining us for this one!

A few weeks later, in early June, we completed our first annual Summer INNS Survey. Over the course of seven survey days we had 6 volunteers assisting several members of staff to record 217 instances of invasive non native species along 36 km of the Test and Itchen. Not only was it incredible to finally collect fresh data for this project, but wonderful to spend several days walking along the picturesque chalk streams of the upper reaches of the Test and Itchen. Check out the T&I INNS Project Portal to see maps from our surveys!

Armed with data from the Summer INNS Surveys 7 strategic sites were chosen to be targeted for removal over July and August. With landowner permission, and assistance in some cases, our dedicated INNS volunteers joined us to remove American skunk-cabbage, Himalayan balsam, monkey flower and orange balsam across several sites in the upper reaches of the Test and Itchen river catchments.

In total the volunteers did an incredible job removing 172 trugs worth of invasive plant material from the river banks and margins across the 7 sites! Between our 8 new INNS Volunteers they dedicated 60 hours of their time to join us for removal events and we couldn’t be more thankful for their help! And thankfully they’ve all said they can’t wait to join us next year, which is very exciting for us.

Did you know the roots of American skunk-cabbage plants can grow horizontally and vertically to depths equivalent to depths half the height of the mature plant – so that could be a whopping 75cm! Monkey flower apparently only grows to 60cm but the plants we were pulling out were bigger than us!

Alongside the efforts of our INNS Volunteers, The Summer INNS Surveys also highlighted 8 sites to be targeted with biological control to reduce the presence of water fern. With the assistance of landowners and river keepers, we were able to release the weevil Stenopelmus rufinasus at 5 sites as planned in July and August, a further 3 have been postponed until early next spring.

Overall, it has been an incredibly successful first season to kickstart this ambitious multi-year project! A huge thank you to all those involved so far and plan on being involved in the future. We are delighted and incredibly grateful for all of the support we have received from riparian owners, stakeholders, local communities and of course our wonderful INNS Volunteers so thank you everyone!

We can’t wait to get back out there next season!