What is habitat restoration?

Many people who cherish California’s landscapes do not have a clear idea of what “restoration” is or what value it has.  Some people also wonder why non-native species are a problem.  Those of us who care about the Channel Islands will benefit from an understanding of both concepts.  The terms “habitat restoration” or “environmental restoration” have many definitions.  In the broadest sense, they refer to returning the functional aspects of a given ecosystem to a semblance of its pre-disturbed state thereby increasing the number and variety of organisms that live there. 

A habitat provides critical feeding, breeding, and nursery areas that organisms depend on to survive.  Once these habitats are disturbed or destroyed, the plants and animals that live there often disappear.  Restoration is helpful in reversing long-term trends in habitat loss and in reestablishing threatened and endangered species.  It can involve many activities including controlling polluted runoff, removal of barriers to migrating animals and reestablishing or maintaining hydrology.  The control of non-native species of plants or animals is most often a major component of a restoration program.

Non-native species cause an estimated $116 billion in economic damage each year in the United States.  Nearly half of the endangered plants and animals nationally have been negatively affected by non-native species.  What’s more, islands have been disproportionately affected by non-native species.  More than 75% of recorded animal extinctions worldwide since colonial times have occurred on islands, and most of these extinctions were caused by introduced species.  On the Channel Islands, non-native species are a threat to the unique plants and animals that exist on the islands and no where else in the world.  Some of these species have already disappeared and others have been driven to the brink of extinction.  Photo: non-native plants like these Eucalyptus trees and the periwinkle covering the ground often spread out of control and almost completely exclude native species. 

When settlers brought trees and shrubs to North America they did not bring any of the predators that kept these plants under control.  This is one reason many weeds spread aggressively and take over important wildlife habitat, devastating shelter and forage while reducing the diversity and quality of native habitat.  Weeds often do not hold and protect the soil the way native plants do, so erosion increases causing sediment in streams.  Weeds can also be a painful nuisance to people using recreational areas on public lands.  If no effort is made to remove some of the most aggressive non-native plants, they soon overwhelm native species.

Not every non-native organism is a problem, and no restoration project can hope to eradicate them all.  Our project primarily works to eradicate or control non-native plants in some of the most sensitive habitats on Santa Cruz Island.  We work with a steering committee of island managers who help us prioritize which plants should be removed and in what areas.  This ensures that we are most effective and our resources are maximized.

Habitat restoration helps ensure that the unique plants and animals that are found on the Channel Islands will thrive and not disappear forever.  It is an essential part of the effort to preserve one of California’s most stunning landscapes for the future.  For more detailed information about habitat restoration, visit the Society for Ecological Restoration web site at, www.ser.org.■