Moles can have a devastating effect on any lawn, although they are most common in sandy, well-drained soils where there is a high population of earthworms, their main food source.
Damage by moles is caused by mounds of earth which may suddenly appear overnight and their tunnelling activity which can lead to an uneven lawn where tunnels have collapsed. They do not usually eat plants, but may eat through plant roots where they interfere with tunnels.
Moles are very territorial and once in your garden can be very difficult to eradicate, so it is best to try to prevent them if there are signs of mole activity in neighbouring areas. If you do manage to remove a mole from your garden, there is a good chance another will take its place unless steps are taken to deter them. There are numerous methods of controlling moles, although success is variable.
An organic, friendly way to discourage moles is to use natural repellents, such as garlic granules, which are a humane and safe way to deter moles from burrowing in your garden.