Surveys conducted by counting pine marten droppings also known as scats, in two Dumfriesshire forests show that artificial dens are boosting pine marten numbers in productive timber plantations.
The plantations in Forest of Ae and Castle O’er are managed by Forestry and Land Scotland and produce over 120,000 tonnes of timber each year.
They’re also home to growing populations of pine marten, a native predator species that gained protected species status in 1988.
FLS says the research shows that productive timber plantations can provide vital, enduring habitat for species like pine marten, particularly if they have an elevated and safe space to rest and breed.
Increased numbers
Pine marten researchers Johnny Birks and John Martin wanted to establish whether artificial dens would boost pine marten numbers in productive plantations.
In partnership with FLS, they installed 50 dens in Forest of Ae in 2020, and none in Castle O’er, to offer comparison.
They have returned every autumn to survey the pine marten, which they do by tracking their scats, or faeces, along a series of fixed 1.5km transects through the forests.
Regular communication with the FLS team means they know which parts of the plantation are being harvested or where and when machinery is on site.
Johnny Birks said: “Productive forests provide the UK with timber, which is vital, but they’re also home to a variety of species.
Spotting scat
The duo estimates how pine marten populations are faring in the forest by counting scats and sending some of them for DNA analysis for authentication.
John Martin said:
“We use pine marten scats as a proxy for population establishment.
“It’s a basic survey method but it indicates population growth or decline. It’s important you can distinguish between pine marten and fox scat – it wouldn’t be obvious to a beginner but do enough of these surveys and it becomes easy to differentiate between them, with DNA confirmation as a crucial back-up.”
The 2023 results were promising.
John Martin said: “Both plantations showed an encouraging increase in the abundance, density and spread of likely marten scats.
“Our DNA results also showed that the species is continuing to establish in both forests.
“Forest of Ae, which has artificial dens, is still leading the way, with 50 scats compared with 15 in Castle O’er. We found several scat clusters, which suggests more communication between neighbouring territory-holders than in Castle O’er.
“Although it’s tempting to attribute the greater numbers at Ae to the artificial dens, the population at O’er could be lagging simply because pine martens started establishing there a year or so later.”
Adapting productive forests for native species
Bill Coombes, regional environment advisor for FLS said: “Plantations like those at Forest of Ae and Castle O’er provide Scotland with much-needed, sustainable timber.
“Trees in plantations tend to be quite young, and so don’t have the cavities that pine marten like to rest and breed in.
“We are therefore managing our forests to retain some areas of older trees and some windblown areas, as well as some dead trees which will provide potential areas for the pine martens to use. These retained areas also provide suitable habitats for a range of flora and fauna as they develop.
“We’re very happy to support this project and monitoring at these two plantations, and we also monitor boxes in Galloway Forest. FLS is adding more artificial dens at key points across the country to control grey squirrels.
“We hope the marten populations continue to grow, and of course, people are very welcome to visit our forests to spot them for themselves.”
FLS manages 312,600 hectares of productive plantations in Scotland. As well as yielding substantial amounts of sustainable timber, the management of these plantations creates a mosaic of stands of varying age and structure, which supports remarkable biodiversity.
These plantations are crucial habitats for many species in Scotland. Furthermore, the timber they produce reduces the amount that is imported to Scotland, thereby protecting more biodiverse, often endemic-rich, natural forests around the world.
