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This project was based on my Master’s thesis work within the Research Training Group ConFoBi (projet B6 on relationships between forest and birds). It contributed to Mariela Yapu Alcazar’s PhD research and I was also under the supervision of Michael Wohlwend.

Summary

This project explored how unpaved forest roads and paths influence bird communities in the southern Black Forest (Germany), a landscape managed under close-to-nature forestry combining wood production, conservation, and recreation (Bauhus et al., 2013; Storch et al., 2020). These management activities create a dense network of small roads and trails that slightly open the forest canopy. While the ecological impacts of large paved roads are well known (Benítez-López, Alkemade & Verweij, 2010), the subtler effects of these narrow, low-traffic structures remain less understood (Šálek et al., 2010; Mammides et al., 2016).

Bird surveys were conducted along a gradient of canopy openness—from forest interiors to paths, unpaved roads, and forest edges—following standardized point count methods (Bibby, 2000; Balestrieri et al., 2017). The results showed that species richness remained relatively constant across all habitat types. However, community composition and functional traits (body mass and wing shape) (Tobias et al., 2022) only shifted at forest edges, suggesting that small canopy openings along roads and paths do not replicate true edge effects. Birds appeared to treat these linear features as part of the forest rather than as distinct habitats.

Overall, the study indicates that narrow forest roads have a limited ecological footprint on bird assemblages in structurally diverse, managed forests. This work contributes to understanding small-scale fragmentation and complements broader research on road ecology (Coffin et al., 2021; Wu et al., 2023).

Publication

Master’s Thesis

Note: the master’s thesis version was not peer-reviewed and may include early-stage analyses that were improved in the publication.

References in the summary

• Balestrieri, R., Basile, M., Posillico, M., Altea, T. & Matteucci, G. (2017). Survey effort requirements for bird community assessment in forest habitats. Acta Ornithologica, 52(1), 1–9.
• Bauhus, J., Puettmann, K. J. & Kühne, C. (2013). Close-to-nature forest management in Europe: does it support complexity and adaptability of forest ecosystems? In Managing forests as complex adaptive systems (pp. 187–213). Routledge.
• Bibby, C. J. (2000). Bird census techniques. Elsevier.
• Benítez-López, A., Alkemade, R. & Verweij, P. A. (2010). The impacts of roads and other infrastructure on mammal and bird populations: a meta-analysis. Biological Conservation, 143(6), 1307–1316.
• Coffin, A. W., Ouren, D. S., Bettez, N. D., Borda-de-Água, L., Daniels, A. E., Grilo, C., Jaeger, J. A. G., Navarro, L. M., Preisler, H. K. & Rauschert, E. S. J. (2021). The ecology of rural roads: Effects, management, and research. Issues in Ecology, Report No. 23. Ecological Society of America, 36 p.
• Mammides, C., Kounnamas, C., Goodale, E. & Kadis, C. (2016). Do unpaved, low-traffic roads affect bird communities? Acta Oecologica, 71, 14–21.
• Šálek, M., Svobodová, J. & Zasadil, P. (2010). Edge effect of low-traffic forest roads on bird communities in secondary production forests in central Europe. Landscape Ecology, 25(7), 1113–1124.
• Storch, I., Penner, J., Asbeck, T., Basile, M., Bauhus, J., Braunisch, V., Dormann, C. F., Frey, J., Gärtner, S., Hanewinkel, M. et al. (2020). Evaluating the effectiveness of retention forestry to enhance biodiversity in production forests of Central Europe using an interdisciplinary, multi-scale approach. Ecology and Evolution, 10(3), 1489–1509.
• Tobias, J. A., Sheard, C., Pigot, A. L., Devenish, A. J. M., Yang, J., Sayol, F., Neate-Clegg, M. H. C., Alioravainen, N., Weeks, T. L. & Barber, R. A. et al. (2022). AVONET: morphological, ecological and geographical data for all birds. Ecology Letters, 25(3), 581–597.
• Wu, N., Hu, B., Wang, Y., Qin, Y., Ma, G., He, H. & Zhou, Y. (2023). Even minor logging road development can decrease the functional diversity of forest bird communities: Evidence from a biodiversity hotspot. Forest Ecology and Management, 534, 120865.