PH25 Wildlife Ecotoxicology II
Exhibit Hall
8:00 AM - Thursday
(PH302) Assessing avian exposure to monosodium methanearsonate (MSMA) as used for bark beetle control in British Columbia forests.
Morrissey, C.1, Dods, P.1, Albert, C.2, Wilson, L.1, Cullen, W.3, Williams, T.2, Elliott, J.1, 1 Canadian Wildlife Service, Environment Canada, Delta, BC, Canada2 Simon Fraser University, Burnaby, BC, Canada3 University of British Columbia, Vancouver, BC, Canada
ABSTRACT- Recent and historical outbreaks of the mountain pine beetle (Dendroctonus ponderosae Hopkins) have caused significant damage to forests in British Columbia through destruction of thousands of hectares of large diameter, mature lodge pole pine, ponderosa pine and white pine. Management strategies employ a variety of techniques to reduce timber losses from beetle outbreaks including the use an insecticide monosodium methanearsonate (MSMA). Given that insectivorous birds, particularly woodpeckers, are attracted to beetle outbreak areas in forests due to increased food availability, they may be subsequently exposed to elevated concentrations of organic arsenicals through ingestion of wood boring insects from MSMA treated trees. We assessed the risk to avian predators through analysis of bark beetles from different life stages and in trees with known MSMA treatment (4 weeks and 1 year after treatment) to determine levels of total arsenic and organic/inorganic arsenic speciation. MSMA metabolites were highest in adult mountain pine beetles relative to larval and pupal stages and other insects collected from trees at both 4 weeks and 1 year post treatment. Concentrations of total arsenic in mountain pine beetles from treated trees ranged from 13.94- 354.1 
g/g dw with the organic metabolite monomethly arsine (MMAA) contributing over 90% to the total arsenic extracted. Mountain pine beetles from reference trees had low concentrations that averaged < 1 g/g dw total arsenic. Debarking indices and radio telemetry methods were used to identify woodpecker foraging on beetle infested trees with and without MSMA treatment. Debarking indices indicated woodpecker foraging of MSMA treated trees was significantly lower than non treated trees. However, approximately 30% of MSMA trees had some evidence of woodpecker foraging (5%-100% debarked), while focal observations and surveys confirmed woodpeckers occupy MSMA stands. Given the extent of mountain pine beetle infestation and the increasing use of MSMA in British Columbia forests, this study addresses important knowledge gaps on woodpecker exposure to MSMA.
Key words: woodpeckers, arsenic, forestry, bark beetles