As a method of tackling climate change and increase biodiversity, conifer plantations are being duplicated across the UK, although at the risk of hurting red squirrel populations.
Red squirrels are already a threatened species listed as decreasing in the ICUN Red List, they are nearing extinction throughout much of the United Kingdom due to the incursion of the grey squirrels. Red squirrels were thought to thrive in conifer type habitats as they are much better adapted to exploiting the food source conifer plantations have to offer. Red squirrels tend to choose small, seeded cones as a diet whereas grey squirrels are more generalist.
However, new research has surfaced which overturns these views and highlights the role of pine martens in these habitats.
Pine martens are native predators and, until very recently, were in decline just like red squirrels. Their numbers have shown an upward trend which is good news for red squirrel populations as they suppress grey squirrel numbers in and around many native broad-leafed woodlands.
This new research, published in Proceedings of the Royal Society B, found that pine martens did not have the same effect on grey squirrel populations in conifer habitats. In fact, in conifer habitats, pine martens were found to be preying on red squirrels because of they no longer had access to a diverse diet.
To gather the data needed for this research, scientists from Queens University, Belfast and the University of St Andrews teamed up with Ulster Wildlife and citizen scientists. Utilising camera traps placed throughout 700 sites in Northern Ireland across a five year time period in search of red squirrels, grey squirrels and pine martens.
The lead author for the research Dr Joshua Twining from Queens University in Belfast, explained the findings to a Guardian environment correspondent –
“In natural woodland, there are diverse amounts of prey, and lots of refuges for squirrels, so red squirrels don’t get predated all that much. But in conifer plantations, where a single species is planted and of uniform age there is very little biodiversity or alternate prey, and an absence of refuges, so pine martens will eat red squirrels to survive here.”
Mr Twining explained that the research him and his peers had conducted suggested that those who manage land and especially woodland, should reconsider whether introducing more conifer plantations should take priority over Britain’s native broadleaf trees.
He goes on to explain that strategies need to be adapted if the country is to continue with the expansion of conifer plantations as opposed to the expansion of native British woodland.
Roughly three-quarters of forested areas in the UK and Ireland are made up of non-native timber plantations.
This is not the first time conifer plantations have caused concern amongst ecologists. More often than not, conifer plantations tend to be monocultures ( habitats with only one or very few different plant species present).
Additionally, conifer plantations tend to be harvested by the timber industry after a few decades. Providing less diversity than native broadleaf tree species. Government tree planting schemes favour conifers because they are easier to plant and harvest.
A spokesperson from the UK Department for Environment, Food and Rural Affairs told the Guardian –
“We are committed to taking action to recover our threatened native species in England, such as the red squirrel. The planting of coniferous trees in England is at a low level, with our Nature for Climate Fund focusing on the establishment of native broadleaf woodlands at a large scale. Alongside our England Trees Action Plan, this will support the recovery of native red squirrel populations across the country.”
