The Nature Conservancy has spearheaded the installation of two fences that will keep pigs and goats out of remote parts of Kauai and protect the island’s water supply.

Pigs and goats trample on native plants, encouraging erosion and disrupting the ecosystem. Trae Menard, The Nature Conservancy’s director of forest conservation, said Thursday the invasive animals are affecting the ability of the forest to recharge the island’s water source. 

The two fences together protect 8,000 acres and create Kauai’s largest pig and goat-free area. 

One fence cuts through the Alakai Swamp. The other sweeps between cliff faces in upper Wainiha Valley. The areas are so remote that crews and fencing materials had to be inserted by helicopter. 

Federal and state funds paid the $700,000 cost with the help of private donors.