functioning. Although grazing strategies other than full exclusion may promote restoration, they are likely to proceed more slowly and run a greater risk of failure.
In riparian areas that support agricultural crops, the long-term loss of native plants and the widespread occurrence of exotic plants increase the difficulty of accomplishing restoration goals, such that active management of riparian areas (using constructed buffer zones) is likely to be needed. Buffer zones are a valuable conservation practice with many important water-quality functions. Under proper conditions, these buffers are highly effective in removing a variety of pollutants from overland and shallow subsurface flow. They are most effective for water-quality improvement when hillslope runoff passes through the riparian zone slowly and uniformly and along lower-order streams where more of the flow transverses riparian areas before reaching the stream channel. Riparian buffer zones should be viewed as a secondary practice that assists in-field and upland conservation practices and “polishes” the hillslope runoff from an upland area.
Even when riparian buffer zones are marginally effective for pollutant removal, they are still valuable because of the numerous habitat, flood control, groundwater recharge, and other environmental services they provide. Unless new evaluation procedures are developed that consider both the water quality and ecological functions of riparian areas, it is unlikely that riparian zone size (width and length) and composition (vegetation types, other features) will be determined in a way that optimizes their potential for environmental protection.
Riparian areas associated with forested, grazed, and agricultural lands provide some of society’s best opportunities for restoring habitat connectivity across the landscape. Management of riparian vegetation in ways that optimize their value as habitat for plants and animals will require planning and action at both site-specific and landscape scales. In addition, more integrated management that uses a functional approach and seeks to optimize habitats for a variety of native species is needed. Much riparian management currently suffers from focusing on a single species or taxon.
Many of the restoration strategies discussed above involve land- and water-use changes that will require a new understanding of why riparian areas are important. Through improved educational programs, the ecological importance and intrinsic human values associated with these lands may be better balanced against the competing wants and needs of a modern society.
Although recreational use provides an excellent opportunity to foster stewardship of riparian areas, most recreational development in riparian areas lacks sound ecological assessment and planning. Future management should combine careful design using a landscape perspective, limitations on certain uses that are