Macro-moths
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Increase moth diversity after upland restoration
Data collection in progress
Cairngorms Connect
Scotland
Problem: In the UK, ancient native woodland is now an extremely localised habitat, largely restricted to the Highlands of Scotland and covering approximately 1% of its former range. This is due to land conversion (deforestation) for sheep grazing, grouse shooting, and an overabundance of grazing deer, combined with a dense mat of heather, that prevent the forest from regenerating.
Action: Cairngorms Connect is removing non-native trees, planting specific tree species that require help to re-establish (enrichment plantings), and reducing deer numbers to allow the woodland to regenerate naturally.
Indicator: Moths are a good indicator of recent habitat change, as they are relatively species diverse and have short generation times, allowing them to respond rapidly to habitat changes. Certain moth species are associated with different characteristics of developing woodland, for example young birch, open woodlands, or mature birch trees. As native woodlands regenerate in restored areas, Cairngorms Connect expects to find a greater diversity of moths. Increased moth diversity will also provide greater prey availability for birds, bats, and wood-ants, species which are expected to re-colonise after restoration interventions.
Methods
Two complementary approaches are being used to monitor macro-moths across the project area. The first is a “longitudinal” study (measuring change through time): four sites are monitored every year at a range of altitudes (300, 500, 700, 900 m above sea level), to track changes in the moth assemblage in real time. The second is a “chronosequence” approach (simultaneously comparing different areas that are at different stages of restoration). Forty sites are monitored in one year across the study area, with a resurvey planned for ten years later. Additionally, 20 sites are monitored in comparison areas in Norway and the Eastern Cairngorms. This is done to indicate how species assemblages in the Cairngorms Connect area compare to areas of geographically and climatically similar habitat under contrasting management regimes.
At each site, moths are surveyed with a light trap (Robinson trap for the longitudinal element, portable Heath trap for the chronosequence element), monthly in June and July (and additionally in August and September for the longitudinal element). From these data, Simpson’s diversity is quantified across the chronosequence sites, and species diversity is quantified across the longitudinal sites. Cairngorms Connect is also looking more closely at key species or groups of species that are known to be woodland indicators.
The same longitudinal and chronosequence approaches are also being used to monitor songbird populations and vegetation.
The Common Quaker moth. Photo: Ellie Dimambro-Denson
A moth trap with temperature probe and rain guage. Photo: Ellie Dimambro-Denson
Results
To date, four years of surveys have been completed at the four longitudinal sites. For the chronosequence element, one year of surveys has been completed at 34 sites within the project area, 20 sites in the Norway comparison area and 19 sites in the East Cairngorms comparison area. A total of 14,428 individual moths of 239 species have been surveyed.
Data are still being collected and analysed, but this page will be updated once we have results to share.
News Articles
Cairngorms Connect website: Celebrating moth night
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