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Current Research

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Current Research


Southwestern Willow Flycatcher Habitat Viewer

U.S. Geological Survey (James Hatten), 2021

An ArcGIS Online (AGOL) page containing historical and predictive maps develop by 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.


Southwestern Willow Flycatcher Habitat Viewer User's Manual

U.S. Geological Survey (James Hatten), 2021

A guide that walks the user through the use of the AGOL-based habitat viewer. 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.

Variation in Salinity Tolerance and Water Use Strategies in an Introduced Woody Halophyte (Tamarix spp.)

Long et al., 2021

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. These results of local adaptation to increased salinity could have implications for continued tamarisk dominance in aridland riparian ecosystems where drought or water management may lead to increased soil salinities. 

Plastic Responses to Hot Temperatures Homogenize Riparian Leaf Litter, Speed Decomposition, and Reduce Detritivores

Jeplawy et al., 2021

A common garden study of six distinct Fremont cottonwood populations across an elevation gradient and covering a range of genomic 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. Results found that all genotypes in the hottest garden produced comparatively small leaves that decomposed quickly and supported lower abundances of aquatic invertebrates, whereas the same genotypes in the coldest garden produced litter with distinct morphologies and decomposition rates.

Invasive Tree Cover Covaries with Environmental Factors to Explain the Functional Composition of Riparian Plant Communities

Henry et al., 2021

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.

Spenders Versus Savers: Climate-induced Carbon Allocation Trade-offs in a Recently Introduced Woody Plant

Long et al., 2021

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.

Adaptive Versus Non-adaptive Responses to Drought in a Non-native Riparian Tree / Shrub, Tamarix spp.

Bush et al., 2021

A common garden experiment to compare the stomatal sensitivity, sap flux, and canopy transpiration of different tamarisk populations. Results showed that higher-elevation tamarisk populations that are adapted to freezing tolerated drought conditions much better than low-elevation populations. Root area to leaf area ratios were also higher in the highest elevation population. Results indicate that rapid changes in ecohydrologic conditions may result in some Tamarix populations becoming maladapted sooner to reductions in available water than others in the western US

Bridging the Research-implementation Gap in Avian Conservation with Translational Ecology

Saunders et al., 2021

An insightful look at several case studies from conservation practitioners and ornithological social scientists to highlight six core principles of translational ecology - an intentional approach in which researchers and practitioners from multiple disciplines collaborate on conservation management. The authors demonstrate how implementing collaboration, engagement, communication, commitment, process, and decision-framing can lead to improved conservation decision-making and delivery of outcomes applicable to specific management decisions. Finally, they recommend strategies for building a stronger translational ecology culture to further improve the integration of these principles into avian conservation decisions.

Salinity Driven Interactions Between Plant Growth and a Biological Control Agent

Long et al., 2021

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. Tamarisk beetles caused a significantly greater reduction in total biomass in the high salinity plants than the low salinity ones (averages of 63% and 32% respectively), likely due to increased water stress and reduced resources to enable regrowth. Although plants compensated for herbivory by regrowing foliage over three defoliation events and maintained similar leaf biomass through regrowth, they ultimately had a reduced basal area and 62% lower root biomass compared to the controls. Thus, herbivory caused a shift in plant allocation of resources from overall growth to compensation, reducing root and stem investment.

Riparian Plant Communities Remain Stable in Response to a Second Cycle of Tamarix Biocontrol Defoliation

Gonzalez et al., 2020

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.

An Herbivore-Induced Plant Volatile from Saltcedar (Tamarix spp.) Is Repellent to Diorhabda carinulata (Coleoptera: Chrysomelidae)

Gaffke et al., 2020

Development of a novel repellant compound for the potential management of tamarisk beetle, specifically the Northern species. 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.



RiversEdge West's

mission is to advance the restoration of riparian lands through collaboration, education, and technical assistance.