Monitoring of three protected saproxylic beetles (Cerambyx cerdo, Osmoderma eremita, Rosalia alpina) in South Tyrol: Population status and habitat management

In this study we present the results of monitoring several important populations of
three protected saproxylic beetles: Cerambyx cerdo, Osmoderma eremita, and Rosalia
alpina. These three species are of special interest since their occurrence denotes the
presence of old trees and near natural forests.

Cerambyx cerdo and Osmoderma eremita were monitored at one site with species-specific
standardised sampling techniques (visual survey transects, pheromone, and bait traps).
Capture-mark-recapture techniques were employed. However, the low number of
recaptures did not allow for a reliable estimate of population size for these species.
Furthermore, additional new occurrences were confirmed, expanding the local known
distribution.

Finally, a target monitoring on a newly discovered population of Rosalia alpina involved surveys of newly placed beech logs and the surrounding natural habitats. This monitoring resulted in 79 individuals counted with 21 recaptures. Using the individual
patterns on the elytra, an open population model for capture–mark–recapture (POPAN
analysis) was used to estimate a local population of 171 adult individuals.
This study sums up the methods, results and conclusions of coordinated surveys and
monitoring of saproxylic beetles from 2023 to 2025 and underlines the need and poten
tial for long-term monitoring to inform targeted habitat management and conservation.