About 20 water voles were found living in Little Houghton marsh
A colony of rare water voles has been discovered thriving in marshland in South Yorkshire.
About 20 of the tiny mammals were discovered during a routine inspection by the Environment Agency at Little Houghton Marsh near Darfield.
The marsh, which is due to be developed into a wetland reserve in early 2010, will now include ponds and ditches for the voles to live in.
Water vole numbers in Britain have been in decline for several years.
The Environment Agency said it planned to provide habitats for several important species at Little Houghton including lapwing and grass snakes.
The plans are also designed to provide natural flood defences.
Andrew Virtue, of the Environment Agency, said: "None of the works will affect the principal function of the washland site, to help protect the people of Darfield from flooding."
"All the excess soil from the works will be removed from site so there will be no loss of flood storage capacity", he added.