Bird diversity and density across elevation gradients in Hyrcanian forests: Unraveling ecological patterns, mechanisms, and conservation strategies.

Articles in Press

Document Type : Research Paper

Authors

1 Soil Conservation and Watershed Management Research Department, Kurdistan Agricultural and Natural Resources Research and Education Center, AREEO, Sanandaj, Iran

2 Department of Agricultural & Natural Resources Development, Faculty of Engineering, Payame Noor University, Tehran, Iran

3 Land Affairs Management of Kurdistan Province, Iran

4 Department of Environmental Science, Faculty of Natural Resources, University of Kurdistan, Sanandaj, Iran

5 Department of Environmental, Department of Environment, Tehran, Iran

10.22124/cjes.2026.9437

Abstract

Understanding diversity patterns along elevation gradients is critical for conservation. This study examined bird diversity and density in relation to environmental variables across elevation gradients in the Saadabad-Naharkhoran forest, a subregion of Iran’s Hyrcanian forests. Birds and environmental variables were recorded within a 25-meter radius at 62 sampling points during autumn and winter 2017–2018. Density was estimated using DISTANCE 6.0, and diversity patterns were analyzed using Canonical Correspondence Analysis (CCA) in CANOCO 4.5. Results revealed distinct bird communities across two elevation classes. Species such as the Coal Tit, Great Tit, and Blackbird were associated with the first elevation class and correlated with variables like shrub cover, temperature, and leaf litter percentage. In contrast, species such as the Tree creeper, Great Spotted Woodpecker, and Nuthatch were associated with the second elevation class and correlated with humidity, canopy cover, and large-diameter trees. These findings highlight the significant influence of elevation gradients and habitat structure on bird community composition. The results underscore the importance of preserving old-growth forest structures and maintaining habitat mosaics to support biodiversity. This study provides valuable insights for sustainable forest management in the Hyrcanian forests, emphasizing the need to balance harvesting practices with conservation efforts.

Keywords

References

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Caspian Journal of Environmental Sciences

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Available Online from 10 February 2026

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