Tackling invasive Tree Mallow to support our seabird populations

As Puffins, Fulmars and Shags begin re-appearing on Fidra and Inchmickery, warden Ally Leonard tells us about the work staff and volunteers have been carrying out on the islands to combat the spread of Tree Mallow.

The Forth Islands are two small islands of less than 5 ha each, within the Firth of Forth.  Inchmickery is situated in the Inner Forth near to Edinburgh and Fidra lies further out close to the seaside town of North Berwick.  Both islands are designated as Special Protection Areas for the large numbers of breeding seabirds found there, including breeding Shags, Fulmars, Kittiwakes, Guillemots, Razorbills, several species of gulls and, of course, Puffins. 

Like seabird populations across the world, these important populations are under threat and one of the biggest challenges faced by seabird colonies that can be acted upon is invasive non-native species (INNS).  In the Firth of Forth, the INNS which has the biggest impact on breeding seabird colonies is Tree Mallow (Lavatera maritima), a fast-growing flowering plant that forms extensive, dense stands of vegetation across the islands limiting breeding opportunities for seabirds, in particular Puffins.

 

Tree Mallow was first introduced into the Forth when it was planted on the Bass Rock by the lighthouse keeper. It is thought to have been used for poultices and in the preparation of ointments to heal burns, and also as toilet paper by lighthouse keepers when the supply boat was unable to land. 

In the mid-2000s, it became clear that Tree Mallow was having an impact on breeding bird numbers, particularly Puffins, on the islands in the Forth.  Since 2011 the RSPB and partners in SOS Puffin have organised regular work parties to clear Tree Mallow. On Fidra, progress is clearly being made in combatting the spread but as one plant alone can produce over 20,000 viable seeds, it is essential that sustained and dedicated clearing continues to prevent any additional seed being added to the seed bank. 

Every year a dedicated group of volunteers spend hundreds of hours out on the islands over the winter months clearing the Tree Mallow before it can set seed. And this year, RSPB Scotland was lucky enough to receive funding from the Scottish Marine Environmental Enhancement Fund (SMEEF) to help carry out this work.

With the funding we employed specialist rope access contractors to clear the Tree Mallow found on the cliffs of Fidra, which is important to help reduce the amount of seeds able to grow on the island

 

With the help of our volunteers, we ventured out to Inchmickery to clear a smaller patch of Tree Mallow before it becomes as wide spread as it is on Fidra and cut down some of the Elder which grows on the island. Elder isn’t as invasive as the Tree Mallow, but it has become very overgrown in the last few years, preventing seabirds from accessing areas to breed and also preventing us from being able to monitor the breeding birds in spring as we simply can’t move across the island in the way that we used to be able to. 

By carrying out this work, we are making these islands even better for the seabirds who call this home in the summer months, and we are very grateful for the support from SMEEF and our partners like the Scottish Seabird Centre.  And now, with spring upon us we are beginning to see the first joyous sights of Puffins and other birds back on the islands.

This project is supported by the Scottish Government’s Nature Restoration Fund, which is facilitated by the Scottish Marine Environmental Enhancement Fund (SMEEF), and managed by NatureScot.