Task 4: Vegetation management
This task identifies sites where vegetative conditions are contributing to erosion. Establishing native trees, shrubs and grasses keeps soils, banks and floodplains in place and functioning properly. Disturbed areas in projects under other tasks are seeded to help jumpstart revegetation. In some cases, fences are built to allow vegetation to recover. A demonstration project using goats to reduce sagebrush and tamarisk is being conducted as part of this task.
Removal of undesirable species
A main element of this task is to remove undesirable noxious and invasive plant species. Critical concerns in the watershed are the invasion of noxious species like tamarisk, or salt cedar, shrubs and Russian olive trees, especially in arroyos and riparian areas. The invasion of these species has helped reduce more desirable native plant species like cottonwoods and willows.
A history of overgrazing and fire suppression has helped to increase monotypic stands of sagebrush, cholla cactus and pinyon-juniper in the watershed. Selective removal of these species allows for the regeneration of grasses. The reestablishment of healthy grasslands provides a pathway for precipitation to infiltrate, and can prevent the movement of large amounts of sediment being washed from the land surface or scoured from eroding gullies that drain into watercourses.
A 3-part demonstration project using goats to control sagebrush and tamarisk is part of this task.
Click on the heading above to read an article about the goat grazing demonstration.
A seed mixture of native grasses and forbs can be effective where upland range and arroyo improvements have been made and seeds are not available on site. Site preparation, mulch, tackifier and fertilizer is used when needed. Seeding is also used to stabilize disturbed areas associated with road improvements or stream channel restoration. An appropriate, certified weed-free local seed mix is used.
Reestablishment of native plants in riparian areas
Riparian areas provide for shading and bank stabilization and are floodplains that act as filters to remove sediment during runoff events. Increasing the growth of desirable native plant species prevents the encroachment of non-native species.
Two methods may be employed to promote reestablishment of riparian areas in decline: the construction of small fence exclosures, and the additional planting of native riparian plants. Exclosures promote the recovery of herbaceous and woody riparian
vegetation and protect existing plants from cattle. Cottonwood and willow poles and rooted cuttings, and plugs of wetland plant species can be planted in suitable areas to reestablish riparian buffers.