Riparian Monitoring Protocol Implementation Plan for park units in the Southern Colorado Plateau Network

Perkins, Dustin; Weissinger, Rebecca; Witwicki, Dana; Thomas, Helen; Wight, Anneth; Lund, Katrina; Van Grinsven, Matthew; McCoy, Lee; Soles, Ellen

In arid and semiarid regions like the Colorado Plateau, riparian zones typically pro-vide a striking visual contrast to surrounding upland environments. Riparian corridors include a notably diverse set of landforms, plant and animal communities, physical processes, and environments within the larger landscape (Naiman et al. 1993). Because of the unique contribution and importance of riparian areas to regional biodiversity (Sabo et al. 2005), and the disproportionately high use of these systems by plant and animal species (Hubbard 1977, DeBano and Schmidt 2004), riparian zones were identified as ecosystems of concern for the Southern Colorado Plateau Network (SCPN). These ecosystems often provide habitat for federal-ly-listed endangered and threatened terrestrial and aquatic species, and are intimately associated with unique geologic features cited in the enabling legislation for a number of national parks and monuments. They are also the primary focus for an array of recreational activities on public lands. Riparian ecosystems, especially in arid and semiarid regions, are universally recognized for their many natural resource values. Yet, they remain vulnerable to a number of persistent and emerging threats. For example, because of features like relatively high rates of flood disturbance, linear connectivity, and high edge-to-area ratios, riparian ecosystems are prone to invasion by non-native species (Planty-Tabacchi et al. 1996, Richardson et al. 2007, Perkins et al. 2015, Scott et al. 2018). Additionally, riparian systems are, and will continue to be threatened by aridification, or a period of transition to an increasingly water-scarce environment (Colorado River Research Group 2018). This is occurring as a direct result of climate-related increases in temperatures, due in part to continued emissions of greenhouse gasses into the atmosphere. Temperature-related losses to the Colorado River will result in flows that are projected to be 20% lower than current flows by mid-century. Any possible increases in precipitation would provide little offset to these declines (Udall and Overpeck 2017). Similarly, increases in primary productivity with rising CO2 levels are not likely to over-come the negative effects of increased aridity; and drought-tolerant, non-native riparian species are likely to outcompete native riparian species like cottonwood (Populus sp.) and willow (Salix sp.) (Perry et al. 2012). SCPN has targeted a broad range of riparian area for monitoring, from ephemeral washes to large, regional rivers, such as the Escalante and Mancos Rivers (Table 1). Final decisions as to which riparian areas will be monitored by SCPN will be made with the affected parks in the fall of 2018. The rationale to be used in selecting sites for monitoring is explained in Appendix A. This Protocol Implementation Plan (PIP) covers all of the targeted riparian areas using two approach-es: 1) for larger streams, SCPN will utilize the Northern Colorado Plateau’s (NCPN) published wadeable streams monitoring protocol (Weissinger et al 2018) which incorporates vegetation, hydrology (groundwater or surface water), and geomorphology; and 2) for several smaller, ephemeral washes, SCPN will utilize Weissinger et al. (2017) to monitor baseline vegetation conditions with a resampling frequency every 5 years, or after major disturbance events combined with more frequent measurements of groundwater wells and geomorphology. For those systems where geomorphology or groundwater is the primary interest, we will conduct measurements of groundwater and/or geomorphology with minimal to no vegetation sampling. In studying such riparian systems, we are interested in understanding how riparian vegetation, hydrology, and geomorphology change spatially and compositionally in response to disturbance events (drought or large flood events), or to longer term changes in precipitation, temperature, surface flows and ground water.

Riparian Monitoring Protocol Implementation Plan for park units in the Southern Colorado Plateau Network

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