title: The role of reproductive phenology, seedling emergence and establishment of perennial Salix gordejevii in active sand dune fields.
abstract: OBJECTIVE
  The function of sexual reproduction of perennials in restoration of vegetation of active dune fields frequently has been underestimated. The objective of this study was to evaluate the role of sexual reproduction of the perennial Salix gordejevii in the revegetation of active dunes.
  
  
  METHODS
  Seedling emergence and establishment of S. gordejevii were examined both in controlled experiments (germination at different burial depths with different watering regimes) and in field observations in three dune slacks. The reproductive phenology and soil seed bank of S. gordejevii, the dynamics of soil moisture, the groundwater table and the landform level of three dune slacks were monitored.
  
  
  RESULTS
  Seeds of S. gordejevii began maturation on 1 May, and seed dispersal lasted from 8 May to 20 May. Seeds on the soil surface germinated significantly faster than those buried in soil (P<0.05). Seedling emergence was negatively correlated with landform level. When most seedlings emerged, there was a significantly positive correlation between soil moisture and seedling emergence (P<0.01). Rainfall was negatively correlated with seedling emergence. Seedling establishment was significantly and positively correlated with seedling emergence (P<0.05), and 72.3 % of the emergent seedlings were established at the end of the growing season. These results indicated that (a) seeds matured and dispersed before the rainy season; (b) seeds germinated as soon as they contacted a moist surface and relied more on soil moisture than on rainfall; and (c) more seedlings emerged at lower sampling points in dune slacks.
  
  
  CONCLUSIONS
  In natural conditions, restoration of active sand dune fields generally commences with revegetation of dune slacks where sexual reproduction of perennials contributes greatly to species encroachment and colonization and hence plays an important role in restoration of active dune fields. Furthermore, aeolian erosion in dune slacks, leading to good soil moisture, facilitates seed germination, seedling emergence and establishment of S. gordejevii.
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, PR China.
authors.forename: Qiaoling
authors.initials: Q
authors.lastname: Yan
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Liu
authors.forename: Junling
authors.initials: J
authors.lastname: Ma
authors.forename: Deming
authors.initials: D
authors.lastname: Jiang
mesh_terms: D017753:Ecosystem; D018525:Germination / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D032108:Salix / Q000502:physiology*; D036226:Seedlings / Q000502:physiology*; D012639:Seeds / Q000502:physiology; D012822:Silicon Dioxide; D012987:Soil; D013997:Time Factors
chemical_list: D012987:Soil; D012822:Silicon Dioxide