Webinar: Biocontrol and restoration: Effects of saltcedar (Tamarix spp.) management on Virgin River

Title: Biocontrol and restoration: Effects of saltcedar (Tamarix spp.) management on riparian habitat and reptiles and amphibians along the Virgin River Date: Friday, October 16, 2015 at 11am CST Presenter: Heather L. Bateman Arizona State University, College of Letters and Sciences, Mesa, Arizona, USA Abstract: Amphibians and reptiles (herpetofauna) have been linked to specific microhabitat characteristics, microclimates, and water resources in riparian forests. Our objective was to relate variation in herpetofauna abundance to changes in habitat caused by a beetle used for Tamarix biocontrol (Diorhabda carinulata; Coleoptera: Chrysomelidae) and riparian restoration. From 2009-2014 we measured vegetation and monitored herpetofauna at locations affected by biocontrol along the Virgin River in the Mohave Desert of the southwestern USA. Twenty one sites were divided into four riparian stand types based on density and percent cover of dominant trees (Tamarix, Prosopis, Populus, and Salix) and occurrence of restoration. Restoration activities consisted of mechanically removing non-native trees, transplanting native trees, and restoring hydrologic flows. Restored sites had three times more total lizard and eight times more yellow-backed spiny lizard (Sceloporus uniformis) captures than other stand types. Woodhouse's toad (Anaxyrus woodhousii) captures were greatest in Unrestored and Restored Tam-Pop/Sal sites. Results from visual encounter surveys indicated that herpetofauna abundance was greatest in the Restored Tam-Pop/Sal site compared to the adjacent Unrestored Tam-Pop/Sal site. Tam sites were characterized by having high Tamarix cover, percent canopy cover, and shade. Two species of herpetofauna (spiny lizard and toad) were found to prefer habitat components characteristic of Restored Tam-Pop/Sal sites. Restored sites likely supported higher abundances of these species because restoration activities reduced canopy cover, increased native tree density, and restored surface water. Without intervention, biocontrol does not by itself improve riparian habitat complexity and native tree recruitment; therefore, restoration of side-channel surface flows and planting native trees may be necessary. This research was funded by the United States Bureau of Reclamation, Desert and Southern Rockies Landscape Conservation Cooperative. Biography: Dr. Bateman is an Associate Professor at Arizona State University on the Polytechnic campus. Dr. Bateman is a field ecologist and conservation biologist interested in how human land-use affects vertebrate populations and habitats, especially in riparian ecosystems. Her research interests lie in exploring population and community responses to habitat alteration, with a particular interest in amphibians, reptiles, and birds. Her current research focuses on exploring the impacts of leaf beetles used as saltcedar biocontrol on herpetofauna populations along the Virgin River in Nevada and exploring impacts of riparian restoration on herpetofauna in the urban Phoenix environment.