Does hybridization among tamarisk beetles change the risk of non-target attack in the field? Clark et al. study the consequences of hybridization in tamarisk beetles (Diorhabda). They paired laboratory phenotyping with genomics to assess changes in risk of non-target attack and body size and fecundity. Body size and early fecundity were similar in pure and hybrid females, indicating that hybridization is not detrimental to insect fitness or the biocontrol program and may provide variation that allows populations to become locally adapted.
What site conditions are associated with greater recovery and overall higher cover of willows? Goetz et al. performed a meta-analysis of tamarisk removal and willow (Salix) recovery across the southwest, compiling data from 260 sites where tamarisk was subject to active removal and/or biocontrol and 132 reference sures. Cut-stump method with biological control was the most effective method to improve native species dominance. Willow cover was generally highest in locations with low drought stress, as reflected by soil properties, distance to water, and climate.
A common garden study of six distinct Fremont cottonwood populations across an elevation gradient and covering a range of genetic variation to determine responses to different heat conditions. The common gardens had mean annual temperatures of 11, 17, and 23°C and all received regular watering throughout the growing season.
A study subjecting tamarisk from two distinct populations originating from areas with greatly varying soil salinities to a range of different salinities. Results showed dramatic differences between growth with the low salinity population accumulating 72% more biomass when grown at 4 ppt compared to 16 ppt, while the high salinity population produced 50% more biomass when grown at 16 ppt. Additionally, the high salinity population had a lower turgor loss point and exhibited greater stomatal control relative to the low salinity population.
A guide that walks the user through the use of the AGOL-based habitat viewer (https://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=b362c94bd7714969805ab7dd29336ce0). User is provided with instructions for changing base map layers, toggling through data layers, utilizing tools to compare different datasets, and locating the metadata for the provided layers. Manual uses screen shots of the AGOL platform to aid in seamless navigation.
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.