Date lodged: 27 February 2018
To ask the Scottish Government what assessment it has been made of the impact of beavers on (a) red squirrels, (b) beech trees and (c) other aspects of biodiversity.
Answered by: Roseanna Cunningham 8 March 2018
a) Scottish Natural Heritage (SNH) assessed the potential interaction and effects (positive or negative) between beavers and other mammal species, including red squirrels, when preparing its ‘Beavers in Scotland’ report submitted to the Scottish Government in June 2015: http://www.snh.org.uk/pdfs/publications/research/Beavers%20in%20Scotland%20-%20Final%20-%2010%20June%202015.pdf
SNH further assessed the likely impact of beavers on red squirrels as part of its preparation for the Strategic Environmental Assessment it has undertaken: ‘Beavers in Scotland Strategic Environmental Assessment Environmental Report’: http://www.gov.scot/Resource/0052/00528945.pdf
Red squirrels were not included in the Environmental Report as any impact on red squirrels from beaver felling activity is expected to be negligible.
b) SNH assessed the potential interaction and effects (positive or negative) between beavers and woodland habitat when preparing its ‘Beavers in Scotland’ report submitted to the Scottish Government in June 2015:
Beaver browsing preferences and effects were assessed as part of the Scottish Beaver Trial woodland monitoring and included comparing results found at Knapdale with those found elsewhere in Europe, including beaver selection of trees: section 5.2 of ‘The Scottish Beaver Trial: Woodland monitoring 2009 – 2013, Final Report’:
Beavers show strong preference for particular tree species e.g. willow, rowan and birch. Beech does not form a native component of any Natura woodland habitat in Scotland. It does poorly on wet ground and is therefore unlikely to form a high proportion of the woodland in areas occupied by beavers. Any impact is therefore likely to be small scale, and localised to individual trees.
c) SNH carried out a review of beaver impacts on biodiversity: ‘A review of beaver ( Castor spp.) impacts on biodiversity, and potential impacts following a reintroduction to Scotland, (2015)’: https://goo.gl/djEqVu .
This reviewed the evidence that beavers act as ecosystem engineers, and included a meta-analysis of published studies. The impact on a wider range of species groups were considered, including plants, invertebrates, fish, amphibians, birds and mammals. It explored the impact beavers will have on the biodiversity of Scotland and in particular, examined the effect of a beaver reintroduction on protected or vulnerable species and habitats.