An ArcGIS Online (AGOL) page containing historical and predictive maps developed by James Hatten of the USGS for the southwestern willow flycatcher habitat across the southwestern United States. The model outputs a range of probabilities for suitable and less suitable habitat in 20% probability classes. This project shows that the satellite model adequately predicts flycatcher habitat rangewide, but it lacks the ability to predict which patches will be occupied in a given year.
Each year, with the help of numerous partners across thirteen states and Mexico, RiversEdge West produces an annual distribution map that notes the presence and absence of Diorhabda spp. from sampling sites across the west. The links below contain all archived tamarisk beetle maps spanning over a decade.
This study employs functional diversity metrics and guilds—suites of species with similar traits—to assess the influence of an invasive tree (Tamarix spp.) on riparian plant communities in the southwestern United States. Nine distinct guilds were identified with a gradient of functional diversity related to both tamarisk cover and environmental conditions. The identified guilds can be correlated to specific site conditions and can be used to anticipate plant community response to restoration efforts and in selecting appropriate species for revegetation.
Researchers looked at non-structural carbohydrate storage in different genotypes of Tamarix from an experimental common garden. Results suggest that Tamarix from colder locations cope with freeze events by maintaining large storage pools to support tissue regrowth, but with the trade-off of overall reduced growth and reproduction.
A two-part study looking at how changes in soil salinity affect tamarisk growth and how beetle-induced defoliation affects tamarisk growing in soils with different salinities. Results showed that tamarisk plants grow better in soils with a similar salinity to their own origin site and that lower salinity does not benefit tamarisk plants adapted to higher saline conditions.
A look at beetle-occupied tamarisk sites 11-13 years after initial occupancy to determine long-term vegetative community response. Study found that Tamarix cover across sites initially declined an average of ca. 50% in response to the beetle, but then recovered. Changes in the associated plant community were small but supported common management goals, including a 47% average increase in cover of a native shrub (Salix exigua), and no secondary invasions by other non-native plants.
Development of a novel repellant compound for the potential management of the northern tamarisk beetle (Diorhabda carinulata). Repellant has been shown to be effective on reproductive adults and alter the behaviors of 1st and 2nd instar larvae. Continued development and field deployment of this repellent compound may provide a new tool for the management of D. carinulata.
Stahlke et al. developed a reference genome for tamarisk beetles (Diorhabda spp.) and reference panel of all four introduced parental species to monitor range expansion and hybridization across North America. They found a substantial genetic bottleneck among D. carinulata in N. America, although populations continue to establish and spread, possibly due to aggregation behavior. Among hybrids, they found that D. carinata, D. elongata, and D. sublineata hybridize in the field, especially in eastern New Mexico, with D. carinata × D.
To what extent has invasive riparian vegetation (IRV) treatment reversed channel narrowing and reduced dynamism trends? Paired treated and untreated reaches at 15 sites along 13 rivers were compared before and after treatment using repeat aerial imagery to assess long-term (~10 year) channel change due to treatment on a regional scale across the Southwest U.S. Wieting et al. found that IRV treatment significantly increased channel width and floodplain destruction.
Clark et al. evaluated theoretical predictions for evolution of reproductive life-history and dispersal traits in the range expansion of the tamarisk biological control agent, Diorhabda carinulata, or northern tamarisk beetle. With experiments run on field-collected populations, they found that females at the expansion front had increased fecundity and body mass, and reduced age at first reproduction; and that dispersal increased at the expansion front in males, especially when unmated and reared at low density.
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.