Assessment of relation between soil characteristics and wood species biodiversity in several size gaps

The role of disturbance in the structure and dynamics of ecological systems is an essential issue in ecology. The purpose of this research was to comparison of soil characteristics in forest gaps with several size and relation to plant species biodiversity in Lalis forests, Chalous. In order to investigate factors, three gap size small gap (200 m2), medium gap (400 m2), and large gap (600 m2) with three replicate were selected in locate. During the late summer 2008, mineral soil samples (0–30 cm depth) were collected from four different places in each gap, all over the gap area randomly. Nine circular subplots of 3.14 m2 (100 cm radius) were established inside each gap. Subplots were positioned one in the central part of the gap and the others along the cardinal directions. The percent of vegetation cover every wood species was estimated in each subplot and in the whole gap. Some of soil characteristics, such as total carbon, total nitrogen, available phosphorous, soil acidity (pH), C/N ratio, and saturation moisture were measured. By using analysis of variance statistical difference between Soil characteristics in respect to gap size were found. Results showed that the highest carbon and C/N ratio is related to small gaps. The highest of nitrogen, phosphorous, pH, and moisture characteristics are related to large gaps, too. Determination of relation between plane cover biodiversity and soil characteristics were accomplished by correlation. Similar to results, by using correlation statistical difference between diversity indices with soil characteristics was found. With thicken of soil characteristics consist of nitrogen, phosphorous, pH, and moisture increased diversity species (Simpson) and richness species (Margalef) indices. On the contrary, with wane of carbon and C/N ratio increased Simpson and Margalef indices.