 In addition to the lateral dispersion ( by invertebrates and deer ) there is also importance in the fact that burial ( vertical dispersion ) by ants ( or other vectors ) increases the survival of new plants by two mechanisms . First , vertical dispersion ensures sufficient depth to preserve the seeds through their dormancy ( Trillium seeds are normally dormant for their first year ) . Second , vertical dispersion ensures adequate anchorage of the rhizomes . This is particularly important for young plants because their small rhizomes , with few & short roots , are easily dislodged ( e.g. frost heaveal and other erosion factors ) and desiccated . 
