مطالعه تغییرات شاخص‌های تنوع زیستی جامعه پرندگان در تیپ‌های پوششی متفاوت جنگل شصت‌کلاته گرگان

The biodiversity of birds has very important roles in ecological researches of forest. The goal of this research was to study the changes in diversity, richness and evenness of bird community in four vegetation cover types, namely, Fagus, Fagus-Carpinus, Carpinus-Parrotia and Parratio-Carpinus-Quercus along summer, autumn and winter in Shast-Kalate forest. First, the homogeneous vegetation units were chosen using field records. The bird sampling was conducted using sampling point procedure. The bird species and the number of all observations in relation to each species in each sampling plot were recorded in three seasons. The species diversity indices were calculated using Simpson and Shannon-wiener and evenness was calculated using Camargo indices. Furthermore, the species richness was calculated and compared in four different types of forest cover. Based on the results, the highest diversity index was observed in winter and the lowest in summer. The indices of diversity and richness in summer and autumn were higher in Fagus forest type and in winter were higher in Fagus-Carpinus forest type compared to the other forest types. The highest evenness index was observed in Fagus forest type. Moreover, the Parrotio-Carpinus-Quercus forest type showed the lowest species richness, species diversity and evenness in the three seasons. The results confirmed the effects of season and different forest cover type on the biological diversity of bird community and illustrated that approaching to cold season along Fagus and Fagus-Carpinus forest type increases the biodiversity indices values. The results also highlighted the importance of forest maturity. However, preventing forest exploitation may not be the best solution for biodiversity conservation, but use of some methods like selection cutting is suggested as one of the most appropriate and sustainable solutions for preserving the structure of forest exploitation and creating suitable habitat for bird species and other wildlife populations.