THE SOIL SEED BANK PATTERN IN HIGHLAND RANGELANDS OF EASTERN ANATOLIAN REGION OF TURKEY UNDER DIFFERENT GRAZING SYSTEMS

Abstract

Soil seed bank dynamics are crucially important for natural recovery of degraded ecosystems. The study was conducted on the natural rangelands applied different grazing system at Kargapazari Mountain in Erzurum, Turkey and was aimed to explain the role of applied different grazing system and soil properties on the abundance and spatial distribution of plant species in the seed bank. Total 73 taxa were recorded, 22 of them were annual species on the experimental area. The species number in the seed bank changed between 26 and 36 among the sites. The winter grazing system (WGS) sites had the highest species richness while spring grazing system (SGS) sites had the lower species richness. The highest perennial grasses seedlings were recorded for spring-autumn grazing system (SAGS) and season-long grazing system (SLGS) sites than the others. Similar differences were also recorded for the other functional groups and common species among the range sites. The differences in spatial distribution of plant species in the seed banks were mainly addressed geomorphological heterogeneity rather than grazing system effect while the differences in seed bank composition among range sites were mainly addressed in the difference of grazing season and pressure originated from grazing system practices. The effects of grazing system practices and soil properties on seed bank composition were clearly explained with Redundancy Analysis (RDA). However, there were great differences in seed bank composition among the range sites and virtually all sites have enough seed stock for natural recovery but current grazing system practices should be improved in favour of increasing seed scattering of desired plants in the experimental area and similar steppe rangelands.