The Nature Conservancy says native plant species have dramatically recovered at a preserve on the slopes of Haleakala on Maui ever since the organization fenced out goats and pigs.

Mark White is the Maui program director for the Nature Conservancy. He said native shrub cover has tripled at Waikamoi Preserve since the hoofed animals were removed and fenced out.

Invasive alien grass also declined in the preserve.

The group surveyed a 1,000-acre area between 6,000 and 8,000 feet above sea level.

Plant ecologist Guy Hughes says the shrubs recovered once goats and pigs weren't trampling over them.

This also lets moss and lichen do well, a sign the ecosystem is recovering.