Beetles
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Increase diversity and abundance
Data collection in progress
Iron Curtain to Green Belt
Bulgaria
Problem: Dead and dying wood is a key component of natural forests that is often missing from commercial forestry plantations. The saproxylic communities that decompose this biomass are among the most diverse functional groups in healthy old-growth native forests, but are scarce in homogeneous plantations.
Action: Plantation forests of non-native and native conifers are being transformed to native deciduous forests through a process of natural regeneration and native species plantings, to create a more heterogeneous natural woodland, including an eventual greater proportion of deadwood from deciduous trees.
Indicator: Saproxylic beetles are good indicators of forest restoration due to their key role in the trophic web of the forest ecosystem and their specificity for the deadwood substrate that characterizes mature natural woodland (Gimmel & Ferro 2018). These beetles are highly sensitive to commercial forest exploitation and forestry management, meaning they are scarce in plantation forestry stands, but should increase as natural forest structure is restored (Dollin et al. 2008).
Cerambyx cerdo. Photo: Rostislav Bekchiev
Alpine longhorn beetele (Rosalia alpina). Photo: Rostislav Bekchiev
Morimus asper. Photo: Rostislav Bekchiev
Stag beetle (Lucanus cervus). Photo: Rostislav Bekchiev
Methods
The key indicator species to be monitored will be three saproxylic beetle species (Lucanus cervus, Morimus asper funereus and Cerambyx cerdo) and the ground beetle Carabus intricatus. The three saproxylic beetles are umbrella species, whose presence will reflect the preservation of many other species typical of deciduous woodlands (Gojković et al. 2022). The ground beetle is dependent on deadwood for shelter and overwintering, and is also highly mobile, meaning that it may potentially be able to respond more rapidly forest restoration by colonising nearby habitats.
Six 1 x 1 km study sites that contain areas undergoing restoration will be surveyed. Within each site, 1-km transects will be walked in three different habitat types: (i) conifer plantation forestry in the process of transforming to native broadleaved forest; (ii) homogenous conifer plantation; (iii) natural deciduous forest.
Data will be collected by two observers walking each survey transect and recording the species and abundance of all the beetles observed. The observers inspect leaf litter, lying tree trunks, standing deadwood and lying deadwood as well as flying individuals. Transects are 1 km long and 10 m wide. Surveys are carried out during the day, ideally between 3pm-7pm, and continue until either one hour has passed or the transect is completed, whichever is soonest. Surveys will be carried out twice per year in June and July from 2024-2027, including a pre-restoration baseline survey in 2024.
Each beetle of the indicator species found will be recorded using the SmartBirds Pro mobile app to allow spatial analyses and relative abundance estimation. The relative abundance will be calculated as the number of individuals of each species per transect.
Habitat data on the forest type and structure will also be collected at each transect surveyed.
A type of flat bark beetle (Cucujus cinnaberinus). Rostislav Bekchiev.
Results
This page will be updated with baseline data, once it is collected, processed and analysed.
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