Does Habitat Restoration Work? A Case Study From Utah's Escalante River

Abstract

The Escalante River ecosystem, like many across the southwestern United States, is threatened by invasive Russian olives trees (Elaeagnus angustifolia).Russian olives are drought tolerant nitrogen-fixers that form dense stands that can alter bank-side, or riparian, communities by outcompeting native willows and cottonwoods These invasives also change rivers by preventing bank erosion, which leads to channelization and degradation of the streambed habitat. In addition, Russian olive leaf litter falling into streams can alter nutrient cycling rates and shift food availability for some aquatic invertebrates. To control Russian olives and prevent their spread, in 2009 the Escalante River Watershed Partnership (ERWP) began removing these trees from Escalante Canyon to restore the river to its natural state. In 2015, students in Collaborative Research in Biology (Biol-423) assisted ERWP in removing Russian olives and conducted a pilot study to assess the effects of removal on riparian and stream invertebrates. Results from that study suggested that invertebrate richness and abundance increased as time since removal increased. To see if this trend was consistent over time, this past March (2018), a second group of Biol-423 students returned to do a follow-up study. Their objective was to resample the original sites and sample the last remaining Escalante River site with living Russian olive trees. This poster shows the results of this 3-year research project.