Riparian ecosystems, located at the interface of terrestrial and aquatic systems, are often given special attention by scientists for their high biodiversity and biological activity (Naiman et al., 1993; Naiman and Decamps, 1997) and significant role in nutrient and energy flux (McClain et al., 2003). Riparian ecosystems are known to buffer environmental impacts and contribute to the maintenance of water quality (Lowrance et al., 1997). For example, riparian zones can intercept, filter, and process anthropogenic nitrogen inputs (Lowrance et al., 1984; Peterjohn and Correll, 1984; Mayer et al., 2007), attenuate phosphorus (Hoffmann et al., 2009), capture sediments (Liu et al., 2008), reduce urban noise (Harris, 1985), and moderate stream temperature (Wilkerson et al., 2006), functions that are especially important in the face of global climate change and continued land use development. Their position in the landscape and linear pathways create critical corridors for animal migration and movement (Hagar, 1999). Thus, riparian areas provide critical ecosystem services that support society and economies (Millennium Ecosystem Assessment, 2005) and are, therefore, essential to human health and well-being. In many regions such as urban and suburban centers, riparian areas remain the last intact ecosystems to provide parks and green space (Groffman et al., 2003). Ultimately, riparian ecosystems are immeasurably valuable. The continual loss of riparian zones represents a loss of ecosystem services (Sweeney et al., 2004). The proliferation of management initiatives for riparian buffers demonstrates a need for sound, quantitative science on riparian ecosystem function and the results of conservation and restoration actions. The contents of this special issue are intended to help inform management decisions that support the values and services riparian ecosystems provide.