Coastal adaptation in action at Cwm Ivy

Cwm Ivy marsh at high tide

Welcome to the Cwm Ivy saltmarsh restoration project site

Cwm Ivy marsh, on the North Gower coast, was claimed from the sea as farmland in the 17th century. It was protected by a sea defence which over the years was increased in size and strength. In 2014 the sea wall breached and the sea is reclaiming the land, transforming Cwm Ivy freshwater marsh to saltmarsh. 

Within this article we’re keeping you up to date with the changes happening at Cwm Ivy. If you scroll back through the posts you can see how it’s transformed from the early days after the breach to the thriving habitat it is today. 

Habitat transformation at Cwm Ivy

This transformation began in 2014 when the sea wall breached and the sea came rushing in to Cwm Ivy marsh for the first time in hundreds of years. 

In the early days, it looked like a sea of mud, as one habitat reacted to the influx of saltwater and started its transformation to a new habitat. 

We were confident that the salty mud and water coming through the breach would bring with it an array of seeds from specialist salt-tolerant plants and that Cwm Ivy marsh would return to its saltmarsh roots. 

We were amazed by the pace of change, and what we can see now, such a short time on, is mind-blowing. We’ve come from those tentative first steps to a thriving habitat, absolutely teaming with wildlife. 


Three years on from the breach

Cwm Ivy marsh, in just three years, has transformed, by the winter of 2017, we had a fully functioning saltmarsh at Cwm Ivy. Watch the video to hear about the transformation and habitat gains at Cwm Ivy.

Monitoring the change

Since the breach, we’ve been regularly monitoring the plants, birds, mammals, invertebrates and sediment composition at Cwm Ivy. This monitoring has helped us to understand the habitat transformation at Cwm Ivy. 

" The rate of change has exceeded all expectations. Just three years on and we have a dynamic and thriving set of intertidal habitats here at Cwm Ivy"
- Corrine Benbow, Salt marsh Project Officer

Through our monitoring we’ve been able to keep a close eye on how the habitat has changed, comparing records from before and after the breach. 

The detailed monitoring allows us to understand the complexity of the developing ecosystem and how this compares with other similar coastal realignment sites. It also enables us to share knowledge with others – the public, schools, scientists and researchers, as well as land managers across the UK. 

Why allow the sea in?

In places like Cwm Ivy, rising sea levels are having a big impact. In line with our Shifting Shores report, which held one clear message… as a nation we can no longer build our way out of trouble on the coast. This meant that at Cwm Ivy, we were no longer trying to defy nature by holding back the tide, instead, letting nature take its course. 

Latest updates

03 Jul 18

Mud beetles galore

These strange excavations can be seen all over any patches of bare mud on the marsh. They’re made by tiny mud beetles…there must be millions of them, judging by the number of mud piles….just another reason why Cwm Ivy attracts so many feeding birds!

Thousands of mud beetle mounds on Cwm Ivy, Gower

18 Jun 18

Gall midge

These mysterious little packages have appeared all over the bistort plants on the fringes of the marsh. They are made by the gall midge Wachtliella persicariae. Each gall contains several larvae that will pupate there inside a cocoon and the bright pinkish/red galls are far easier to spot than the midges themselves!

Mysterious midge packages all over the marsh, Cwm Ivy, Gower

09 May 18

Flowering Saltmarsh

Our wonderful group of welsh mountain ponies are doing a cracking job of grazing the saltmarsh at Cwm Ivy, allowing the habitat to flower fully whilst keeping control of scrub and invasive Spartina grass.

Ponies controlling invasive species, Cwm Ivy, Gower