Determining and comparing grazing zones based on animals’ dung in semi-steppe rangelands: The case of North Iran

Cattle dung distribution in rangeland ecosystems is uneven and affects nutrient availability to plants. Identifying spatial patterns of dung is crucial for understanding the ecological process of system functioning and grazing intensity. The aims of this study were to determine changes in deposited dung in various grazing intensity zones, as well as to find any possible pattern between accumulated dung and distance from the watering point in plain rangeland of Inche-Shourezar in North of Iran. For this purpose, five zones at distances of 50, 150, 350, 650, and 1050 m from the watering point were selected. It measured dung number and weight within plots of 25*50 cm size. Comparison of means showed significant differences of dung amount among the zones except 150 and 350 m (P-value ≤ 0.01). A declining trend was found in moving from the center to the further zones, therefore it is necessary to decrease livestock concentration around socialization points to avoid rangeland degradation. Quadratic regression was the best-fitted model for distance and dung number (r2 = 0.915) while cubic regression was fitted significantly for distance and dung weight (r2 = 0.901). The finding of this research confirmed that grazing gradient and dung deposition don’t necessarily follow a linear way, while specifically, the dung number parameter showed a more realistic spatial distribution and more coefficient of determination than dung weight. Therefore, using the dung number is a more appropriate method than the dung weight to determine the grazing intensity. It can be concluded that grazing zones are significantly determinable through the calculation of livestock dung. Therefore, using dung as a proxy and rapid method is suggested to estimate the grazing intensities at plain rangelands.