Peat areas, in particular, need to be kept waterlogged to help the growth of sphagnum moss.
Grants from the Species Survival Fund and the Nature for Climate Peatland Grant Scheme have allowed work to begin and the trust has launched an appeal to help fund the remainder of the project.
Head of wilder landscapes Rob Farrington said: “Wild Woodbury demonstrated how effective wetland restoration can be for water quality and wildlife.
“At Tadnoll Heath, Dorset Wildlife Trust will build on that success to create more habitats, strengthen ecosystems, and ensure Dorset’s rivers and wetlands thrive for generations to come.
“Public support is essential to make this possible.”