Effects of Agriophyllum squarrosum seed banks on its colonization in a moving sand dune in Hunshandake Sand Land of China

Abstract A field study was conducted in a moving sand dune to detect the effects of different positions of the dune and the burial depth on seed number, germination rates of Agriophyllum squarrosum in the soil seed banks and its colonization during natural succession processes. The results showed that wind and the movement of sand played an important role in the colonization of A. squarrosum seed banks. The positions of sand dune and burial depth significantly affected the number of seeds in soil seed banks. The number of seeds was more abundant at the top of the dune and windward slope than at leeward slope, and it reached a maximum at the 10–20 cm depth. The number of seeds was fewer at leeward, and decreased with increasing burial depth. However, there was no significant difference in the germination rates of seeds among positions of the sand dune. Therefore, the plant density at the windward slope and tops was higher than that at leeward. Our results suggested that the seeds of A. squarrosum were more likely to be deposited at the dune tops and windward slopes than at leeward, and thus to form larger seed banks. At the sand dune tops and the windward slope, the seed number at 10–20 cm depth was much greater than at 0–5 and 5–10 cm burial depths. However, the germination rate of seeds at 0–5 and 5–10 cm depths were significantly higher than that at 10–20 cm depth. The results indicated that it was the germination rate at the top 0–5 and 5–10 cm, rather than the total number at the 10–20 cm that determined the observed higher density of A. squarrosum at the dune tops and the windward.