The leaf beetle Diorhabda elongata Brullé subspecies deserticola Chen, collected in northwestern China, has been released in the western United States to control tamarisk (Tamarix spp.). While beetle establishment and saltcedar defoliation have been noted at northern study sites, this species has not established at latitudes south of the 38th parallel.

The northern tamarisk beetle Diorhabda carinulata (Desbrochers) was approved for release in the United States for classical biological control of a complex of invasive saltcedar species and their hybrids (Tamarix spp.). An aggregation pheromone used by D. carinulata to locate conspecifics is fundamental to colonization and reproductive success.

A presentation by Dan Bean at the 2020 RiversEdge West Conference about new knowledge on aggregation phermones, phenology, and genomics. 

Riverine ecosystems are known to provide important habitat for avian communities, but information on responses of birds to differing levels of Tamarix is not known. Past research on birds along the Colorado River has shown that avian abundance in general is greater in native than in non-native habitat.

In this chapter, Carothers et al have three objectives: first, they document the value of nonnative Tamarix as summer habitat for birds compared to native riparian habitats of mesquite bosques and cottonwood/willow, and mixed deciduous gallery woodlands; second, they specifically focus on the unintended consequences to native avifauna of dam construction, Tamarix invasion, native vertebrate colonization of the Tamarix-dominated riparian habitat, and subsequent biocontrol along approximately 300 miles of the Colorado River in Grand and Glen Canyons; and, third, the

Remote sensing methods are commonly used to monitor the invasive riparian shrub tamarisk (Tamarix spp.) and its response to the northern tamarisk beetle (Diorhabda carinulata), a specialized herbivore introduced as a biocontrol agent to control tamarisk in the Southwest USA in 2001.

A 2006 review of the saltcedar (Tamarix) biocontrol program. 

 

DeLoach, C.J., Milbrath, L.R., Carruthers, R., Knutson, A.E., Nibling, F., Eberts, D., Thompson, D.C., Kazmer, D.J., Dudley, T.L., Bean, D.W. and Knight, J.B., 2006. Overview of saltcedar biological control. In Monitoring science and technology symposium: unifying knowledge for sustainability in the Western Hemisphere. Proceedings RMRS-P-42CD. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado (pp. 92-99).

Stabler and Still estimate density and standing biomass of tamarisk along waterways in a northwest to southeast transect in Oklahoma to test the hypothesis that environmental conditions in northwest Oklahoma would make successful invasion by tamarisk more likely. They found that the invasive potential of tamarisk in Oklahoma is likely limited by streamflow and climate but not by soil salinity. 

"This case challenges the Animal and Plant Health Inspection Service’s (“APHIS”) 2010 decision to terminate, without taking necessary remedial action, the agency’s program authorizing wide-scale release of an invasive species known as the tamarisk leaf-eating beetle (“beetle”) that is having, and will continue to have, devastating effects on the highly endangered Southwestern willow flycatcher (“flycatcher”) and its habitat, including designated critical habitat."

Ctr. for Biological Diversity v. Vilsack, 276 F. Supp. 3d 1015 (D. Nev. 2017)

In this 2010 Memo from the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS), USDA - APHIS terminates the tamarisk biocontrol program.

In this November 20, 2014 letter, Secretary of the United States Department of Agriculture Vilsack responds to Senator John McCain regarding impacts of the tamarisk biocontrol program on the federally-listed, endangered southwestern willow flycatcher. 

This document is an update to the previous risk analysis that was produced on August 9, 2017, to help inform decision makers of the spread potential of Diorhabda beetles and the potential control options available within the authority of APHIS to limit impacts to the SWFL and designated critical habitat. APHIS updated the analysis in response to a remedial order from the United States District Court for the District of Nevada on June 19, 2018.

 

Remedial order issued to address nontarget effects by the tamarisk beetle on the endangered Southwestern Willow Flycatcher. Lists actions required of Animal and Plant Health Inspection Service (APHIS). 

Center for Biological Diversity v. Vilsack, No. 2: 13-cv-1785-RFB-GWF (D. Nev. June 19, 2018).

Guide to establishing wetland hydrology, vegetation, and wildlife habitat functions on soils capable of supporting those functions.

Guide to maintain, develop, or improve wetland habitat for waterfowl, shorebirds, fur-bearers, or other wetland dependent or associated flora and fauna.

A guide to restoring wetland function, value, habitat, diversity, and capacity to a close approximation of the pre-disturbance conditions.

Document intended to guide enhancement of soil functions, hydrology, vegetation and habitat specific to wetlands.

Nagler et al. test the assumption that removing saltcedar (Tamarix spp.) will save water and create environments more favourable to these native species. They compared sap flux measurements of water used by native species in contrast to saltcedar, and compared soil salinity, ground water depth and soil moisture across a gradient of 200–1500 m from the river's edge on a floodplain terrace at Cibola National Wildlife Refuge (CNWR).

Glenn et al. measure transpiration and stomatal conductance to investigate the environmental constraints on an arid-zone riparian phreatophtye, saltcedar (Tamarix ramosissima and related species and hybrids), growing over a brackish aquifer along the Colorado River in the western U.S. Depth to groundwater, meteorological factors, salinity and soil hydraulic properties were compared at stress and non-stressed sites that differed in salinity of the aquifer, soil properties and water use characteristics, to identify the factors depressing water use at the stress site.

In this 2014 poster, Ryan and Harris report preliminary results on a study of evapotranspiration (ET) at the Cibola National wildlife Refuge. They ask whether groundwater responds to a massive change in ET of surface vegetation and assess baseline well and evapotranspiration data as a proxy for the anticipated tamarisk beetle migration.