Effects of Soil Moisture on Vegetation Invasion into Transition Zones between Windword Slopes of Active Dunes and Interdune Lowlands

Abstract

During the vegetation natural regenerations in semi-arid sand areas, seed germination and seedling emergence are critical phases of maintaining plant population and realizing natural regeneration. It is generally accepted that soil moisture and soil seed bank are primary dependent factors in the phases. But the binary correlation analysis between seedling density and soil seed bank density as well soil moisture in transition zones between windword slopes of active dunes and interdune lowlands indicated that the correlation between seedling density and soil seed bank density was not significant (P > 0.05) in the plant growing season; but the one between seedling density and soil moisture was significant and positive (P < 0.05); moreover, seedling density increased logarithmically with the increasing of soil moisture. The conclusions reveal that soil moisture is a primary dependent factor during seedling emergence and establishment in the transition zones between the windword slopes of active dunes and interdune lowlands, but soil seed bank is not; and plant natural regeneration depends more on those propagating seeds from plant communities in neighbouring sand dunes.