Weeds & Infestations

The spread of invasive weeds is a growing problem in Wilderness nationwide. Seeds are easily transported to trailheads on the wheels of motor vehicles, and then carried into the Wilderness by hikers, pack stock, other animals, wind, and flowing water. Hay for packstock is also a culprit in spreading weeds. Non-native invasive plant species are finding their way into even the most remote Wildernesses. Once established, many of these species aggressively out-compete native vegetation, replacing native grasses and forbes with mono-culture stands of weeds. This change in vegetation has significant effects on the availability of food and habitat for many species including ungulates, predators, insects, and birds.

Invasive weeds pose a real management dilemma, given their significant impact on native ecosystems. The magnitude of ecological impact may vary from one situation to the next, so it is difficult to present simple hard and fast rules for handling invasive plants and weeds in Wilderness. The following discussion is therefore intended to offer some general guidelines and factors to consider when faced with a weed control issue in Wilderness.

The rapid spread of non-native invasive plants and weeds is a concern on all land nationwide, not just in Wilderness. The invasions begin outside of Wilderness, where there is intensive human activity and soil disturbance. In other words, invasive weeds in Wilderness are a problem that originates outside the wilderness, not within it. For this reason, intensive eradication treatments should focus primarily on areas outside Wilderness where weeds originate. Unless the spread of weeds is successfully halted outside the Wilderness boundary, then intensive eradication efforts inside Wilderness will ultimately fail.
Management approaches to controlling the spread of noxious weeds range from preventive measures such as public education, to more intensive actions such as hand-pulling, using domestic goats to graze the plants before they can go to seed, aerial and hand-held spraying of herbicides, and introducing biological controls such as certain insects adapted to controlling specific weed species.
Inside Wilderness the major emphasis should be on measures to reduce the transport of weeds into the Wilderness. Such preventive measures include public education, requiring certified weed-seed-free feed for packstock,, and possibly locating trailheads several miles from the wilderness boundary. Hand-pulling to eliminate small plots of weeds can curb their spread within the Wilderness.

Use of intensive measures such as the aerial spraying of herbicides are highly controversial, with many unknown effects on ecosystems and human health. Whether aerial herbicides should be used anywhere is a topic worthy of significant debate. If aerial spraying is considered at all, it should be restricted to areas outside the Wilderness because it violates the untrammeled nature of Wilderness as defined by law. Aerial application of herbicides inside wilderness is rarely, if ever, necessary because until weeds are first brought under control outside Wilderness, there will be no successful way to permanently eradicate them inside Wilderness no matter how much herbicide is deployed. For this reason, the control of invasive weeds in Wilderness should rely primarily on methods that are compatible with wilderness and protection of Wilderness values including its untrammeled quality.
Intensive and incompatible control measures should never be undertaken merely for purposes of enhancing public land grazing allotments in Wilderness, or boosting populations of game species.

Although hunting and livestock grazing are allowable uses of Wilderness, they are not the statutory purpose of Wilderness and therefore an area’s untrammeled quality should not be compromised simply to accommodate non-Wilderness activities unrelated to wilderness protection. In such circumstances the appropriate approach would be to rest or retire the grazing permit to decrease the soil disturbance that is conducive to the spread of weeds, and reduce the number of hunting permits to a level that is compatible with current game populations while also implementing non-intensive weed control measures that are compatible within Wilderness.