Biocontrol & Threatened and Endangered Species Amanda Stahlke1*

Applying Satellite-based Habitat Models to Inform Riparian Habitat Restoration and Management Actions for Two Listed Riparian Species, the Southwestern Willow Flycatcher and the Yellow-billed Cuckoo 

  James Hatten1, Jennifer Holmes2, and Matthew Johnson3* 

Using Tamarisk Beetle Pheromone Lures to Reduce Re-growth of Tamarisk Following Tree Cutting  Cynthia Brown1*, Hannah Ertl2, Dan Bean3, Zeynep Ozsoy4, Farley Ketchum Sr.5, and Emily Swartz6 

An Integrated Pest Management Plan for the Bill Williams River National Wildlife Refuge. This plan outlines the biological degradation of native riparian forest habitat along the Lower Colorado River and the invasive species management actions needed to protect and restore riparian forests and marshlands of the Bill Williams River. 

DeRango, B., 2023. Integrated Pest Management Plan Bill Williams River National Wildlife Refuge.

From the abstract:

An understanding of trait-environment relationships is particularly important in the case of invasive species which may alter abiotic conditions and available resources. This study is the first to measure the functional response of riparian plant communities to biocontrol of an invasive species.

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.

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.

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.

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.