Density and cover of winter annual plants

The purpose of this investigation was to answer three general
questions:
1. How does the modification of soil properties and the ratios of
resources (e.g., water-N) by ants alter species assemblages of
winter annual plants at the edge of the ant nests?
2. How does the \\\\"spring cleaning\\\\", clipping, predation or
herbivory by ants affect success of the winter annual plants at
the edge of ant nests?
3. Are there significant differences in the floristic assemblage
and belowground standing crop (root biomass) between the edge of
ant nest and the surrounding unaffected soils?

Data set contains density and cover of all winter annual plants
measured at regular intervals. Density is expressed as the
number of individuals of a species per square meter. The cover
of each species was calculated as the area covered by a
perpendicular (not vertical) projection of its aerial parts onto
the ground surface and expressed in covered area (cm squared) per
square meter.