Ant-hill heterogeneity and grassland management

1. In many grasslands, some ants act as ecological engineers to produce long-lasting soil structures which have a considerable influence on the patterns and dynamics of plant, vertebrate and invertebrate species. They promote species richness and diversity.
2. The yellow meadow ant, Lasius flavus, is the most abundant allogenic ecological engineer in grazed European grasslands, producing vegetated long-lasting mounds. Its ratio of influence to biomass is remarkably high. Grassland restoration projects frequently attempt to re-introduce grasslands on abandoned arable fields. When this ant does not colonise naturally it should be introduced. It probably limits the abundance of grasses in a similar manner to hemi-parasitic plant species.
3. Ant-hills make a distinctive contribution to grassland heterogeneity. Measurements on mounds in a single grassland over 45 years document the dynamics of the same 200+ ant-hills in volume, surface area and basal area. As the mounds aged they increase...