High‐resolution riparian vegetation mapping to prioritize conservation and restoration in an impaired desert river

Abstract

In highly impaired watersheds, it is critical to identify both areas with desirable habitat as conservation zones and impaired areas with the highest likelihood of improvement as restoration zones. We present how detailed riparian vegetation mapping can be used to prioritize conservation and restoration sites within a riparian and instream habitat restoration program targeting 3 native fish species on the San Rafael River, a desert river in southeastern Utah, United States. We classified vegetation using a combination of object‐based image analysis (OBIA) on high‐resolution (0.5 m), multispectral, satellite imagery with oblique aerial photography and field‐based data collection. The OBIA approach is objective, repeatable, and applicable to large areas. The overall accuracy of the classification was 80% (Cohen's κ = 0.77). We used this high‐resolution vegetation classification alongside existing data on habitat condition and aquatic species' distributions to identify reaches' conservation value and restoration potential to guide management actions. Specifically, cottonwood (Populus fremontii) and tamarisk (Tamarix ramosissima) density layers helped to establish broad restoration and conservation reach classes. The high‐resolution vegetation mapping precisely identified individual cottonwood trees and tamarisk thickets, which were used to determine specific locations for restoration activities such as beaver dam analogue structures in cottonwood restoration areas, or strategic tamarisk removal in high‐density tamarisk sites. The site prioritization method presented here is effective for planning large‐scale river restoration and is transferable to other desert river systems elsewhere in the world.

The NorWeST Summer Stream Temperature Model and Scenarios for the Western U.S.: A Crowd‐Sourced Database and New Geospatial Tools Foster a User Community and Predict Broad Climate Warming of Rivers and Streams

“…Useful covariates might include inventories of channel realignments, water diversions, or detailed measures of riparian canopy conditions. Promising in the latter category are new remote‐sensing applications for describing riparian vegetation and site‐potential shade (Dauwalter et al, ; MacFarlane et al, ; Wawrzyniak et al, ), although these tasks are made more challenging by the prospect that climate change may also alter future riparian communities (Catford et al, ).…”

Big biology meets microclimatology: defining thermal niches of ectotherms at landscape scales for conservation planning

“…In extreme instances, human-assisted migrations into thermally suitable but otherwise inaccessible habitats might also be considered (Thomas 2011). Remote sensing is a promising tool that is increasingly used to provide high-resolution local information about vegetation characteristics (Bode et al 2014, Dauwalter et al 2015, MacFarlane et al 2016) and habitat morphology (McKean et al 2008, Harpold et al 2015) but requires various forms of calibration to represent the environmental nuances most relevant to ectotherms. Different tactics could be emphasized at those boundaries, including protection and restoration of riparian vegetation and instream flows to maximize shade and ameliorate stream warming ( Fig.…”

“…Management and regulatory communities sometimes have that information but it may not be in geospatial or database formats suitable for efficient spatial analysis, so developing databases and ensuring compatibility with strategic models are important future tasks. Remote sensing is a promising tool that is increasingly used to provide high-resolution local information about vegetation characteristics (Bode et al 2014, Dauwalter et al 2015, MacFarlane et al 2016) and habitat morphology (McKean et al 2008, Harpold et al 2015 but requires various forms of calibration to represent the environmental nuances most relevant to ectotherms. Moreover, estimating unimpaired site potential relative to current conditions is a significant challenge for remote sensing or any habitat assessment technique, and one that will only become more difficult as that potential changes in association with climate or other global change agents (Catford et al 2013).…”

CO-RIP: A Riparian Vegetation and Corridor Extent Dataset for Colorado River Basin Streams and Rivers

“…This dataset can support novel research on the potential effects of riparian habitat fragmentation, and inform future land-use and riparian network connectivity planning in the basin [57]. The riparian vegetation map could be immediately applied to prioritize potential areas for restoration and conservation activities in the Colorado River Basin [58]. For example, in the western US, there are more than 70 avian species considered to be riparian habitat obligate or dependent [59,60].…”