Department of Physics, Chemistry and Biology (IFM)

Oak and pine stands in the eastern Mediterranean basin represent habitats of different land use and management. Many oak stands have a long history of traditional management followed by recent abandonments, while many pine stands are recently established as conventionally managed forestry plantations. Differences in human utilization of the forest resources have created forest habitats with different stand attributes and associated biodiversity. Knowledge about the distribution and richness of biodiversity associated with different forests is therefore crucial for sustainable forestry planning and management. This study showed that pine and oak forest stands harbor different set-ups of bird assemblages and differ in their capacities to support suitable habitats for some birds. Oak stands supported higher bird species richness and diversity, and a higher proportion of unique species. The number of bird territories did not differ between stands of oak and pine, suggesting that there are no differences in the availability of total food resources. At the level of guilds, ground-nesters (including some mainly insectivorous passerines) and primary hole-nesters (woodpeckers) were significantly more abundant in oak stands, indicating that pine stands lack some features vital in supporting species belonging to these guilds. Although stand age and stand structure were found to be the most important variables determining bird assembly structure, the abundance of ground-nesters and primary hole-nesters were more likely to be explained by the factor forest type. Analyzed for pine stands only, the strongest association was found between ground-nesters and the amount of grass and herbaceous vegetation in the forest understory. For primary hole-nesters the associations with stand structure in pine stands were less clear due to few observations. These results, however, indicate that the differences in abundance of these guilds may be explained by a combination of lack of suitable nest sites and shortage of food resources. For bird assemblages inhabiting oak stands, structures important for nesting and foraging may be closely connected to the properties of the trees themselves, e.g. through existence of cavities and leaves utilized by invertebrates to feed upon. The replacement of oak stands to pine plantations, a common measure in many parts of the Mediterranean basin, is not an ecologically sustainable forestry practice, and will result in the inevitable loss of highly oak-associated species.

In order to provide suitable habitats for birds highly associated with oak forests, these habitats need future conservation. Forestry planning should focus on conserving old stands and promote recruitment of new oak stands to secure oak continuity at a landscape scale. More research is needed to further evaluate the biological values of oak stands in southwestern Turkey.

Forestry practices of managed pine stands in Isparta province should strive for increasing the amount of old trees, preferably by extending the rotation time or develop a more selective logging technique to secure pine continuity. A certain amount of understory cover of shrubs, low trees and vascular plants also need to be retained to benefit birds associated with such attributes, and enhance overall species richness in managed forests.