Data from: Benefit or ecological trap? Monitoring the effects of small clear-cuts on capercaillie Tetrao urogallus and its mammalian predators
Data files
Apr 01, 2025 version files 106.10 KB
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capercaillie_clearcut_data.CSV
88.77 KB
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predator_clearcut_data.CSV
13.56 KB
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README.md
3.77 KB
Abstract
The shift to “close to nature forestry” as the dominating forestry regime in Western-European forests has resulted in increasing timber volume and denser forests with negative effects on photophilic species. Hence, there is an increasing focus on active habitat management measures to support these species. To guarantee that the measures prove beneficial to the target species, it is essential to evaluate both their benefits as well as possible negative effects. However, while species’ population trends are often well-studied, rigorous monitoring schemes for management interventions are often lacking.
Here we applied a before-after-control-intervention (BACI) study design over multiple years to study the effects of actively creating small clear-cuts of up to 1 hectare on the occurrence of western capercaillie (Tetrao urogallus) and its mammalian predators. While habitat management measures had immediate positive effects on the probability of capercaillie presence that remained constant during the 5 years after the intervention, predator presence did not increase in the years after clear-cutting. Assuming that predator activity density is related to predation risk, this would refute the hypothesis that the intervention created an ecological trap.
Our study confirms correlative studies indicating that the creation of small clear-cuts in a closed forest matrix represents an effective measure for improving capercaillie habitats in Western-European lower mountain forests, and contributes to a solid basis for science-based, large-scale management strategies to comply with international species conservation legislation.
Dataset DOI: 10.5061/dryad.k0p2ngfjw
Description of the data and file structure
Data was collected to study the effects of actively creating small clear-cuts of up to 1 ha on the occurrence of western capercaillie (Tetrao urogallus) and its mammalian predators.
We collected data on capercaillie occurrence and habitat suitability on 30 paired study sites (15 pairs), distributed across the Black Forest. For each pair, a small clear-cut of 0.7–1.0 ha was experimentally created in the centre of one study site (intervention, I), while the other served as control (control, C). On each study site we systematically placed 13 sampling plots on which the terrestrial recording of capercaillie occurrence and habitat variables was carried out once per year from 2018 to 2023.
Furthermore, on each study site we monitored potential capercaillie predators by camera trapping from 2018 to 2021 and calculated predator trapping rates for red fox (Vulpes vulpes), badger (Meles meles), marten (Martes sp.) and wild boar (Sus scrofa).
Files and variables
File: capercaillie_clearcut_data.CSV
Description:
Data on capercaillie (Tetrao urogallus) occurrence at the plots between 2018-2023 and habitat suitability in 2018, before the intervention.
Variables:
- plot_id: Individual identifier for each sampling plot. This id consists of the number of the site pair (1-15), an I for intervention or a C for control and the number of the sampling plot (1-13).
- site_pair: Number of the paired sites (1-15).
- study_site: Individual identifier for each study site. This id consists of the number of the site pair and an I for intervention or a C for control.
- year: The year of the sampling.
- capercaillie_occurrence: 0 for no capercaillie signs (e.g. feathers, faeces, dust baths) were found and 1 for capercaillie signs were found.
- period: B for before the intervention (2018) and A for after the intervention (2019-2023).
- treatment: I for intervention (clear-cut) or C for control.
- hab_suit_2018: Initial habitat suitability in 2018, before the creation of the clear-cuts in 2018. We modelled habitat suitability as the probability of finding capercaillie signs at a plot as a function of the habitat variables using the model of Coppes et al. (2020), which had been calibrated with data collected with the same sampling method from different European capercaillie populations and therefore provides a robust estimate.
File: predator_clearcut_data.CSV
Description:
Data on predator trapping rates at the plots between 2018-2021.
Variables:
- site_pair: Number of the paired sites (1-15).
- study_site: Individual identifier for each study site. This id consists of the number of the site pair and an I for intervention or a C for control.
- year: The year of the sampling.
- species: Name of the species for which the trapping rate was calculated.
- trapping_rates: We calculated trapping rates per species, season and site as the number of trapping events (accounting for the number of individuals, e.g. counting a trapping event with two individuals twice) divided by the number of days the camera was active.
- period: B for before the intervention (2018) and A for after the intervention (2019-2023).
- treatment: I for intervention (clear-cut) or C for control.
Reference:
Coppes, J., Kämmerle, J.-L., Grünschachner-Berger, V., Braunisch, V., Bollmann, K., Mollet, P., Suchant, R. and Nopp-Mayr, U. 2020. Consistent effects of wind turbines on habitat selection of capercaillie across Europe. – Biol. Conserv. 244: 108529.