ARS | Publication request: Ecosystem effects of Diorhabda elongata (leaf beetle) on Tamarix invaded riparian systems

Submitted to: Water Resources Association
Publication Type: Abstract Only
Publication Acceptance Date: August 12, 2007
Publication Date: October 16, 2007
Citation: Snyder, K.A., Uselman, S.M., Jones, T.J. 2007. Ecosystem effects of Diorhabda elongata (leaf beetle) on Tamarix invaded riparian systems [abstract]. Nevada Water Resources Association-Truckee River Symposium. p. 21.

Technical Abstract: Saltcedar (Tamarix ramosissima) is a pernicious invader of riparian areas in western rangelands. The release of a biocontrol agent, Diorhabda elongata (leaf beetle), was done across several western states in an effort to control saltcedar by defoliating Tamarix with a predator from its native range. In Nevada this has impacted several drainages, including the Truckee River. However, little is known about the interactive effects of saltcedar invasion and subsequent defoliation by the leaf beetle on ecosystem dynamics. The objective of this research is to understand the effects of leaf beetle/saltcedar interactions on water use and nutrient cycling. We have established a site along the Truckee River where the beetle occurs in extremely low densities, allowing us to establish baseline conditions prior to widespread defoliation. We are monitoring ecosystem carbon and water flux with an eddy covariance system, groundwater levels, and plant water source use (shallow soil or groundwater) using stable isotopes. This will provide us with an integrated understanding of water use in this system. To determine the effects on nutrient cycling we have initiated a litter decomposition experiment that will compare litter decomposition rates of litter from beetle affected trees with litter that fell from trees without the beetle. We will assess the impact of long-term herbivory on N mineralization rates in the Humboldt Basin along an herbivory chronosequence and along the Truckee River. Results of this research will provide an ecosystem-level understanding of the impacts of biocontrol on saltcedar invaded riparian ecosystems.