Butterflies are well placed among British terrestrial insect and other invertebrate groups to act as indicators of the state of the environment. They are highly sensitive to environmental conditions and have rapid lifecycles. In addition, they have widespread appeal and as a result we have developed a good understanding of their ecology in the UK and have an incredible wealth of data on the distribution and abundance of most of the UK's 59 resident and regularly occurring migrant species.
The UKBMS uses a structured survey methodology to monitor butterfly populations across the UK year-on-year. This long-term butterfly data enables us to assess the impacts of climate change, land use and the progress of policy initiatives such as the UK Biodiversity Action Plan, agri-environment schemes and site condition monitoring of Sites of Special Scientific Interest (SSSIs).