Rangeland Ecology & Management

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INTEGRATING TAMARIX BIOCONTROL WITH CONVENTIONAL MANAGEMENT METHODS IN SOUTHWESTERN RESERVOIRS
Author
Murray, Leeland
Lehnhoff, Erik
Schutte, Brian
Sutherland, Carol
Publisher
Society for Range Management
Publication Year
2018
Body

Tamarix spp., invasive riparian shrubs, are ecological and economic threats in the southwest as they displace native vegetation and necessitate costly management. Tamarix control typically consists of chemical and mechanical removal, but these methods can prove to have negative ecological and economic impacts. Tamarisk beetles (Diorhabda spp.) released for biocontrol, are becoming increasingly established within Western river systems and are another form of control. While there is abundant research on each of these treatment methods, no research has been conducted on integrating these methods to improve management. Our work, conducted at Caballo Reservoir in southern New Mexico addressed the question, could Diorhabda herbivory be combined with mechanical and chemical treatment to achieve greater control with fewer non-target impacts. A field experiment was conducted by testing the impacts of integrating mowing and herbicide with herbivory at a standard and low rate (2.78 lb ae ha-1 and 0.93 lb ae ha-1 respectively), with treatments replicated five times, at two field locations � a seasonally flooded and dry site. Green foliage percent and gas exchange (via LI-COR 6400) were measured. Results showed herbicide treatments reduced transpiration rates and green foliage at both sites, and was influenced by adults and larva beetle numbers. At the end of two growing seasons, herbivory alone showed a high green foliage percent recovery, while mowing and herbicide treatments all displayed severely reduced percentages of green foliage.� Data shows combining conventional management methods with biocontrol could result in additional stress through a combination of reduced green foliage recovery and a continued reduction in aboveground biomass within mowed treatments. Incorporating this new knowledge into land management objectives for Tamarix control can result in more effective overall management plans.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Reno, NV