In 1977, California removed the last herbivores from San Miguel Island after years of overgrazing. Decades later, the barren landscape produced a stunning ecological comeback, transforming into an island covered with native vegetation

San Miguel Island offers one of California’s clearest examples of how a damaged landscape can recover when the pressure on it finally stops. The island was heavily grazed for more than a century by introduced livestock, including thousands of sheep. By the 1970s, much of the land had suffered from lost vegetation, exposed soil and erosion. Then the last feral burros were removed in 1977, ending the major grazing pressure that had shaped the island for generations.

The recovery did not happen overnight. San Miguel did not suddenly turn green the year the burros disappeared. Instead, native plants gradually began reclaiming areas where they could still find enough soil, moisture and shelter to survive. Decades later, the difference is striking. A place once described in historical accounts as a “barren lump of sand” now supports broad areas of native vegetation and provides habitat for wildlife found nowhere else.

San Miguel island had a long ranching history

San Miguel Island sits at the western end of Channel Islands National Park, off the Southern California coast. Its isolation makes it feel remote, but for much of the 19th and 20th centuries, the island was used for ranching. Sheep were especially important, with the NPS reporting that thousands were once kept there.


The animals put constant pressure on the island’s vegetation. Sheep grazed the grasses and other plants close to the ground, while cattle, horses and burros also moved across the landscape. On an island already exposed to strong winds, losing plant cover created a serious problem because there was less vegetation holding the fragile soil in place.

The 1977 removal was not the beginning of recovery

The year 1977 is important, but it is not the whole story. The final sheep were removed in 1966, when a remaining group of 148 animals was found and eliminated. Feral burros continued to live on San Miguel until they were finally removed in 1977.

That distinction matters because the island’s ecological recovery began before the last burro left. Once sheep grazing ended, some native vegetation had an opportunity to return. The removal of the burros later eliminated another source of grazing and trampling, giving recovering plant communities a much better chance to spread.

Native plants had survived in protected places

One of the most interesting parts of San Miguel’s recovery is that nature did not have to start completely from nothing. Some native plants survived in places where livestock could not easily reach them, including steep cliffs and canyon walls. Seeds also remained in parts of the soil.

When grazing pressure disappeared, those surviving plants became important sources for new growth. Native grasses and flowering plants could spread into areas that had previously been kept bare by animals. Over time, vegetation began doing something that livestock grazing had made difficult for decades: holding the soil together and creating better conditions for other plants to grow.

The landscape changed, but not everywhere at the same speed

San Miguel’s recovery is impressive, but it is not a story of every part of the island returning to its original condition. Some areas suffered severe erosion, and where the original soil was lost, natural recovery has been much harder.

That is especially important on an island exposed to strong winds. Once loose soil begins moving, vegetation has a harder time becoming established. The National Park Service continues to manage invasive plants and protect native species because removing the original problem does not erase all of the damage that came before it.

Wildlife benefited from the vegetation comeback

The return of plants changed more than the appearance of San Miguel Island. Vegetation provides food, cover and nesting areas for wildlife, including species that are closely associated with the Channel Islands.

The island supports endemic wildlife such as the San Miguel Island fox and deer mouse, along with several Channel Islands bird species. As native plant communities became stronger, they helped rebuild the habitat on which these animals depend.

This is why San Miguel matters beyond its own coastline. The island shows how removing an introduced species can set off a much larger ecological change. Plants return first, soil becomes more stable, and habitat gradually improves.

San Miguel island is still a protected, difficult place to visit

For visitors, San Miguel is very different from a typical California beach destination. The island is remote, weather can change quickly, and access is controlled because of its sensitive environment and history as a former military site.

The National Park Service requires visitors to follow specific access rules, and some areas can only be visited with a park-approved escort. There is also no regular food or drinking-water service on the island, so anyone planning a trip has to prepare carefully before leaving the mainland.

Camping is available at the Lester Ranch area, where the NPS lists nine primitive campsites. Reservations are required, and visitors must bring their own water and supplies. The island is best approached as a protected wilderness area rather than a conventional tourist attraction.

The biggest lesson from San Miguel is not simply that removing livestock made the island greener. It is that ecosystems can sometimes repair themselves when the pressure preventing recovery is removed, even after years of serious damage.

But the island also shows why recovery takes patience. Some native plants returned because seeds and surviving vegetation were still present. Other areas remain difficult because erosion removed the soil those plants needed. San Miguel’s recovery is therefore both encouraging and realistic.