The Press and Journal (Inverness, Highlands, and Islands)
The ‘Anthill Mob’ comes to rescue of hairy climate heroes in the woodlands
Agroup of volunteers nicknamed the ‘Anthill Mob” have rushed to the rescue of climate-hero ants under threat from an invasive, non-native plant.
Hairy wood ants boost the carbon absorption of woodland, but risk being overwhelmed by gaultheria shallon, a garden plant that has gone wild to become a serious pest in Scottish woodlands.
Over the winter, volunteers Chris and Meg Mellish surveyed the nests of hairy wood ants at Woodland Trust Scotland’s Ledmore and Migdale woods in Sutherland.
More than 50 anthills were found, but the survey also revealed an immediate threat to the insects.
Site manager Ross Watson said: “Some of these newly discovered nests were surrounded by an invasive garden plant, gaultheria shallon, which is also threatening parts of the oakwood.
“The ants prefer sunny, open glades that are south facing, and so does the plant.
“If left unchecked, it forms dense thickets that exclude native vegetation.
“It would overwhelm our ant nests, too, if we let it.”
He added: “This is also a great example of the vital role our volunteers play in managing these sites.
“Without the time and care from Chris, Meg and the others, these nests may well have been lost.”
Mr and Mrs Mellish were joined by more helpers to become a gaultheria clearance squad known as the Anthill Mob.
This spring, they have been manually removing the plant from around the anthills.
Woodland Trust Scotland hopes to eradicate the plant eventually, but it will likely need repeated attacks to finally clear it.
The common garden plant spreads to the wild when birds eat its berries and pass the seeds out in their droppings.
Once one plant is established, it spreads via underground stems.
The hairy wood ant, also known as formica lugubris, collects large quantities of honeydew from sap-sucking aphids in trees.
This honeydew is a major
source of carbohydrate for the adult workers and represents a significant input of carbon into soils in forests where they live.
A close relative of the hairy wood ant has been shown to account for up to 39kg of carbon per hectare, per year.
Aside from their carboncapturing role, wood ants are a keystone species affecting many other organisms.
They remove insect pest species from trees and provide food for other animals, including capercaillie and badgers.
Wood ants eat a variety of other insects including caterpillars and beetles, but the bulk of their diet is made up of honeydew they “milk” from aphids.
In return, the ants protect the aphids from predators.
Wood ants are commonly
seen moving up the trunks of pine trees to collect honeydew from pine aphids living high in the canopy.
Ledmore and Migdale is the most northerly Woodland Trust site in the UK.
It was once part of Andrew Carnegie’s Skibo Estate and lies around the small village of Spinningdale, on the shore of the Dornoch Firth.