The biological control agent (tamarisk beetle, Diorhabda spp.) has been used to defoliate non-native saltcedar (Tamarix spp.) in riparian systems throughout the West since 2001. Many non-native plant control activities have the potential to impact non-target plants and wildlife. Biologists do not yet understand the impacts beetles will have on wildlife species utilizing defoliated habitats. The Virgin River in Arizona and Nevada is now the stage where the tamarisk beetle is predicted to expand. Herpetofauna can respond to changes in habitat and they forage in areas where beetles are active. Therefore, the objective of my study is to determine the potential impacts of biocontrol in riparian areas on vertebrate species such as herpetofauna. During 2009, I studied amphibian and reptile assemblages along the Virgin River prior to beetle introduction and conducted feeding trials with Diorhabda and native lizards. Field sites included three Tamarix–dominated riparian areas and four mixed native tree (Populus, Salix, and Prosopis) –Tamarix areas. I used mark-recapture methods to compare herpetofauna abundance and species richness in these habitats. I conducted feeding trials with four common lizard species to determine if Diorhabda was a potential food source.
Results/Conclusions
Here, I present preliminary data from one year prior to beetle establishment along the lower Virgin River. Traps were open from 32 to 37 days in 2009 with over 600 captures representing 8 species of herpetofauna. Preliminary results indicate that relative abundances of lizards were similar in Tamarix and mixed sites, however species-specific abundances differed. Three out of four lizard species did consume Diorhabda during feeding trials and lizards did not show a preference for Diorhabda over crickets (family Gryllidae). These results provide baseline information on herpetofauna abundances in riparian habitats prior to Diorhabda introduction and confirm Diorhabda as a potential food source for native reptile species.
