B.J. Butterfield | Geology Reports

USGS2019

Effects of high flow experiments on riparian vegetation resources in Grand Canyon

Flood events have historically had a strong impact on riparian vegetation within Grand Canyon. Pre-dam sandbars were nearly devoid of perennial riparian vegetation due to the magnitude and frequency of periodic floods (Turner and Karpiscak, 1980). Vegetation has increased since dam closure (Waring, 1995), particularly since the early 1990s (Sankey and others, 2015). This increase in vegetation is attributable to multiple aspects of dam operations, including the low magnitude and duration of High-Flow Experiments (HFEs), specifically flows at 45,000 cfs or smaller over 96 hours. Thus, we begin by providing a broader context for understanding vegetation change, and how other factors interact with HFEs to determine their influence on riparian vegetation. We then discuss the potential mechanisms by which HFEs may impact vegetation, the empirical evidence for those impacts and associated confidence in that evidence, and future research approaches to better fill these gaps in our understanding.

Arizona↗

USGS2016

Prestoration: Using species in restoration that will persist now and into the future

Climate change presents new challenges for selecting species for restoration. If migration fails to keep pace with climate change, as models predict, the most suitable sources for restoration may not occur locally at all. To address this issue we propose a strategy of “prestoration”: utilizing species in restoration for which a site represents suitable habitat now and into the future. Using the Colorado Plateau, USA as a case study, we assess the ability of grass species currently used regionally in restoration to persist into the future using projections of ecological niche models (or climate envelope models) across a suite of climate change scenarios. We then present a technique for identifying new species that best compensate for future losses of suitable habitat by current target species. We found that the current suite of species, selected by a group of experts, is predicted to perform reasonably well in the short-term, but that losses of prestorable habitat by mid-century would approach 40%. Using an algorithm to identify additional species, we found that fewer than ten species could compensate for nearly all of the losses incurred by the current target species. This case study highlights the utility of integrating ecological niche modeling and future climate forecasts to predict the utility of species in restoring under climate change across a wide range of spatial and temporal scales.

Arizona, Colorado, New Mexico, Utah↗