轮牧对荒漠草原土壤种子库特征的影响OA

The soil seed bank is crucial for maintaining the stability,diversity,and genetic integrity of grassland plant communities.Knowledge of the impact of grazing disturbance on the soil seed bank is essential for the scientific management of grasslands.This research focused on two desert grasslands in gravelly sierozem desert steppe and sandy loam sierozem desert steppe.Field rotational grazing experiments and indoor germination tests were conducted to examine the effects of short-term rotational grazing on the soil seed bank.Results indicate that rotational grazing is not significantly altering soil seed bank density in desert grassland of either soil texture;however,it is driving an increase in perennial plant seed proportions,with seeds showing strong concentration within the 0-5 cm soil layer.Compared to grazing exclusion by fencing,the gravelly sierozem desert steppe under rotational grazing showed an increase in the Shannon index and a decrease in the Simpson index.In contrast,the sandy loam sierozem desert steppe had increases in both the Margalef and Simpson indices.However,the Pielou index of the seed bank did not change significantly with rotational grazing in either type of grassland.The similarity between the seed bank species and aboveground vegetation species was low,with the sandy loam sierozem desert steppe showing overall higher similarity than the gravelly sierozem desert steppe.In the gravelly sierozem desert steppe,the seed bank was mainly influenced by soil factors such as available potassium and pH,while in the sandy loam sierozem desert steppe,it was more affected by total phosphorus and ammonium nitrogen.This study suggests that rotational grazing has a significant impact on the species composition and density of the soil seed bank in desert steppe.Soil texture and environmental factors collectively impact soil seed bank dynamics.