Impact of olive grove management on spider (Araneae) community in northwestern Turkey


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Biyolojik Bilimler Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: MERT ELVERİCİ

Danışman: CEMAL CAN BİLGİN

Özet:

Olive (Olea europea) plantations cover vast areas on the Aegean coast of Turkey, including the southern foothills of Kaz Mountains. In such environments, olive trees dominate the terrestrial vegetation in such a way that they might form a novel ‘ecosystem’. The ‘olive grove agro-ecosystem’ is shaped by agricultural management while impacts on biodiversity are largely unknown. As representatives of local biodiversity, spider communities were sampled in soil and vegetation microhabitats, alongside with various environmental variables linked to management or habitat features in organic and conventional olive groves, and in relict patches of natural habitats. 278 spider species from 20,167 specimens and >300 sampling units were collected and standardized by effort. Data obtained were analyzed by using multivariate statistics to interpret associations within the community (NMDS, CCA, RDA models) and by diversity statistics (ANOVA, ANOSİM and permutation tests). Community composition and diversity differed by habitat type (moist or dry grove, maquis, pine and mixed forests) and microhabitat (soil, herb and canopy). Olive groves and mixed forests had richer communities compared to maquis and pine patches. Soil microhabitats were more species rich and diverse than herb or canopy layers. Difference between “organic” or “conventional” management types could not be detected at the community level, whereas impact of soil management (tillage and herbicides) and vegetation cover (tree, shrub or herb cover) were significant on the spider community. Our results may serve as evidence for community composition - environment relationship for spider communities, and help towards more naturefriendly olive grove management in the region.