Richmond Park is probably best known for its majestic deer herds that roam the landscape. However there is another smaller and more secretive animal that shapes the iconic grasslands, the yellow meadow ant (Lasius flavus).
Acid grassland is a nationally important habitat that covers around 67 per cent of Richmond Park. These grasslands are scattered with thousands of mounds that many may mistake as tussocky grass clumps, however these are in fact ant- hills that have been carefully crafted by yellow meadow ants. Some of these mounds are thought to be decades or even centuries old, and are of incredible ecological importance to our grasslands.
What lays beneath these large mounds is truly fascinating! The ants in a single colony work tirelessly over many lifetimes to build one mound that increases in volume over time: they can be up to one metre tall and two metres across…amazing! The yellow meadow ant, like all ants, is social and forms colonies made up of thousands of female worker ants which are quite tiny at just 3-5mm long. At any one time these mounds may be inhabited by between 8,000 and 14,000 individuals, with one queen, who is considerably larger than her workers. Queens have been known to survive for up to 22 years. They are then replaced when they die, enabling the colony to live on and keep building! To maintain this healthy working colony the queen can lay an impressive 100 eggs per hour.
Yellow meadow ants in Richmond Park
So why are these ants and their hills so important? Yellow meadow ants are ecosystem engineers, shaping and modifying their habitat around them. Not only are the hills a home for them, but they are responsible for a higher diversity in both the flora and fauna of the grasslands. They act as a food source for a number of insect-eating birds including the green woodpecker, of which the yellow meadow ant makes up 80% of its winter diet. A multitude of fauna are attracted to the ant-hills by their sun-warmed soils, including small copper butterflies and the common lizard, which enjoy basking atop the mounds.
The ant hills micro-climate and soil composition differs from that of the surrounding grassland, which enables a variety of other species of flora to flourish, such as flowering plants, grasses, lichens and fungi. Together all of these elements provide a unique and biodiverse habitat that is incredibly special. The grassland soil is kept healthy and porous due to the numerous tunnels and galleries built by the ants that crisscross within the mound.
Bugs in the ground
So next time you are wandering through Richmond Park don’t forget to watch your step and look out for the mounds of grass and just imagine the incredibly intricate and fascinating world that is right beneath your very feet. Yellow meadow ants and their mounds, without doubt play a vital role in increasing plant species richness and diversity in grasslands and are a much valued species across the Royal Parks.
The Royal Parks Mission: Invertebrate Project Officer