Moles are usually a nuisance to a homeowner. As they live underground and burrow holes. They are considered as a pest in some countries. They contaminate silage with soil particles and make it unpalatable for animals. They disturb the soil which damages the young plants, allow weed invasion in the garden. They are also involved in damaging the drainage system and watercourses. For more details about their harmful effects and remedial action see the link below:
en.wikipedia.org
en.wikipedia.org