Role of soil mesofauna in reflection of site conditions for oak regeneration (Quercus brantii Lindl.) in Zagros forests (case study: Dalab, Ilam Province)

This study aimed to investigate the role of soil mesofauna for quick and low cost detection of well and poorly seed-origin oak regenerated sample plots in Zagros oak forest ecosystem. The main question of this study is why some areas have a suitable number of natural seedlings while some others do not, despite the presence of mature oak trees? In this study, we sampled 30 100-m² plots with regeneration and 30 100-m² plots without or with only few seedlings in the same physiographic conditions. Soil samples for mesofauna investigation were randomly collected within each sample plot to a depth of 0-20 cm. Soil mesofauna was extracted with a Berlese-Tullgren funnel apparatus.According to CCA ordination, plots with and without natural regeneration have shown, respectively, clumped and uniform patterns of mature oak trees based on Johnson and Zimmer index. In this regard, plots with a clumped pattern were characterized by higher saturation percentage, total phosphorus, total potassium, clay, organic matter, total nitrogen and cation exchange capacity than uniform to random patterns of oak trees. Seed-origin oak regeneration patterns around mature oak trees in plots with and without natural regeneration were clumped and uniform, respectively. The results showed that the number of soil mesofauna in clumped pattern (with higher regeneration) was higher than those in the uniform pattern (with lower regeneration).