You are here:
Riparian Habitat Changes Across the Continental UnitedStates (1972–2003) and Potential Implications for Sustaining Ecosystem Services
Citation:
Jones, K. B., T. E. Slonecker, M. S. NASH, A. C. NEALE, T. G. WADE, AND S. Hamann. Riparian Habitat Changes Across the Continental UnitedStates (1972–2003) and Potential Implications for Sustaining Ecosystem Services. LANDSCAPE ECOLOGY. Springer, New York, NY, 25(8):1261-1275, (2010).
Impact/Purpose:
Riparian buffers consisting of natural land cover have an ecological importance that often far exceed their spatial extent in the landscape (Baker et al. 2006). Riparian buffers often serve as corridors for species migration and possess a disproportionately larger number of plant and animal species than adjacent areas, but especially along stream and river corridors that transcend arid, urban, and agricultural landscapes (Jones et al. 1985; Naiman et al. 1993; Knopf and Samson 1994; Spackman and Hughes 1995; Naiman and DeCamps 1997; Storey and Cowley 1997; Skagen et al. 1998; Woinarski et al. 2000; Groom and Grubb 2002; Lee et al. 2001; Boutin and Belanger 2003; Lees and Peres 2008). Intact riparian buffers also provide important ecological functions in developing catchments, including dissipation of energy associated with flooding events, storage of nutrients and sediments, and filtering of other non-point source pollution that would otherwise end up in streams (Swanson et al. 1982; Lowrance et al. 1984; Peterjohn and Correll 1984; Rhodes et al 1985; Jones et al. 2001; Kiffney et al. 2003; Sweeney et al. 2004; Vidon and Hill 2004; Dwire and Lowrance 2006). Native vegetation cover along the edge of the riparian zones also helps reduce stream bank erosion (Likens and Bormann, 1974; Swanson et al., 1982; Lowrance et al., 1984; Rhodes and Skau, 1985) and water temperature (Chen et al. 1998). Riparian buffer protection and restoration may be key to off-setting the impacts of global climate change, especially in rapidly developing landscapes (Killeen and Solorzanno 2008).
Description:
Riparian ecosystems are important elements in landscapes that often provide a disproportionate range of ecosystem services and conservation benefits. Their protection and restoration have been one of the top environmental management priorities across the US over the last several years. Despite the level of concern, visibility and management effort, little is know about trends in land cover within riparian buffers. Moreover, little is known about whether or not cumulative efforts to restore and protect riparian zones and floodplains are affecting the rates of riparian habitat change nationwide. To address these issues, we analyzed riparian land cover change between the early 1970s and the late 1990s/early 2000s using existing spatial data on hydrography and land cover. This included an analysis of land cover changes within 120 m riparian buffer zones, and at catchment scales, for 42,363 catchments across 63 ecoregions of the continental US. Total natural land cover and forests declined by 0.7 and 0.9% respectively across the study period. Gains in grassland/shrubland accounted for a lower percentage of total natural land cover loss. Conversely, urban and developed land cover increased by more than 1.3% across the study period. Despite these changes, we documented an opposite trend of increasing proportions of natural and forest land cover in riparian buffers versus the catchment scale. We surmise that this trend reflects cumulative efforts to protect riparian ecosystems across the US. However, existing models limit our ability to assess the impacts of these changes on specific ecosystem services. We discuss the implications of changes observed in this study on the sustainability of ecosystem services. We also recommend opportunties for future riparian change assessments.