National Mammal Week 2020 Day 2: Dwarf shrub and Heath
Nature Scot (formerly Scottish Natural Heritage) Mammal Advisor Rob Raynor writrs about ‘A Managed Habitat that Benefits Our Only Native Lagomorph’
Our purple heather-clad hills in August and September present a striking and colourful upland spectacle much admired by visitors and regarded by many as how the hills should naturally look.
It is, of course, a highly managed habitat maintained by systematic rotational burning, to promote ideal conditions for red grouse, but its extent has been declining since the 1940s due to changes in land-use such as upland afforestation and conversion to grassland. In addition to heather, such dwarf shrub habitats usually also comprise various other woody species, including blaeberry (bilberry) and cowberry etc, plus a range of other characteristic upland plant species, but heather predominates.
Of our two hare species, the native mountain hare (Lepus timidus) is better able to cope with a poorer quality diet comprised of much woody vegetation, hence its association with this upland habitat. It turns out that management for grouse also creates perfect conditions for mountain hares and it is no coincidence that the highest densities of the latter occur on land that is managed primarily for grouse shooting, because the mosaic of varying ages of heather created by controlled burning, benefits the hares in just the same way. So, while in the more “natural”, wooded mountain hare habitat of Scandinavia there are typically only around three hares per square kilometre (comparable with poorer quality open hill and forested habitat in Scotland), on managed grouse moors densities can be 20 or 30 times this and, exceptionally, up to around 300/km². It’s a reality that if our moors were allowed to revert back to more natural conditions with extensive areas of scrub and montane woodland, the mountain hare population would be expected to decline accordingly, before stabilising at a new lower level.
Mountain hares are easy to identify in the winter and early spring, with their white or mainly white fur, but from late spring to late autumn they have greyish fur and can be confused with the brown hares and rabbits which usually live at lower levels.
Although there are still areas of Scotland with high densities of mountain hares, there is concern about their conservation status, with the available population information suggesting declines in some areas. The picture is further complicated by natural fluctuations in the population, whereby numbers can vary dramatically over periods of about a decade.
To improve our understanding, NatureScot (formerly Scottish Natural Heritage) has been working with several other organisations including the James Hutton Institute and the Game & Wildlife Conservation Trust to develop and pilot a new bespoke mountain hare monitoring scheme, based on night-time counts using spot-lights along fixed transects in set areas across the Highlands. However this method, while effective in open moorland, is only practical in terrain that is not too steep or craggy. In practice, this means it is restricted mainly to the hills of the central and eastern Highlands, leaving extensive areas in the west and north-west where other approaches to counting hares are needed. One option, to be trialled over the next year, is to involve citizen scientists from a range of backgrounds and interests to record the mountain hares they see (along with selected upland bird species if they wish), either on informal hill walks such as routes up the higher summits over 3,000 ft (the “Munros”), or in defined survey squares, using a modified version of the Mammal Society’s Mammal Mapper smartphone app. We hope this trial will be well supported and can subsequently form part of a more comprehensive national monitoring scheme that includes night time lamping counts, thereby providing more reliable population information for use in assessing conservation status and to help inform management decisions.
How Can You Help?
More information about the scheme will become available over the coming months on the NatureScot website – see https://www.nature.scot/
Mammal Mapper is currently being updated to support this exciting new project and we will have more news on the way soon! Meanwhile you can download Mammal Mapper for free and start recording the mammals you see today! Learn more about the app here
You can learn more about the mountain hare here