Preparing the Southwestern Willow Flycatcher for the Tamarisk Leaf Beetle in the Middle Rio Grande, NM; Ondrea Hummel

¹ Tetra Tech, Albuquerque, NM, USA; ondrea.hummel@tetratech.com, joe.schroeder@tetratech.com 

Tamarisk (Tamarix spp.; aka saltcedar) is an invasive shrub that has become a major nesting substrate for the federally endangered Southwestern Willow Flycatcher (Empidonax traillii extimus; flycatcher) [1]. The tamarisk leaf beetle (Diorhabda spp; TLB) is an introduced biocontrol agent which feeds on tamarisk, triggering defoliation events. Defoliation of tamarisk during the flycatcher nesting season (May – July) decreases nesting success by exposing flycatcher eggs and nestlings to potentially lethal temperatures from direct sunlight and increasing nest parasitism. 

 

Tetra Tech was contracted by the U.S. Army Corps of Engineers to develop a spatial model to identify priority areas for flycatcher habitat restoration in the Middle Rio Grande. Tetra Tech’s Albuquerque Office Environmental Team integrated their collective experience in ecological restoration, stream engineering, GIS and remote sensing applications, and flycatcher habitat relationships to develop a flycatcher habitat restoration siting model which, in combination with field investigations, was used to identify the top 0.5% of potential flycatcher habitat restoration opportunities within the Middle Rio Grande.

 

The flycatcher habitat restoration siting model provides a timely solution for flycatcher conservation in the form of a siting tool that can be used to efficiently allocate funding for flycatcher habitat creation within the Middle Rio Grande. 

 

[1] More than 50% of flycatcher nests in the Middle Rio Grande, NM, have been documented in tamarisk since 2011 (Moore and Ahlers 2017).