Climatic limitation of emerald ash borer impacts on black ash in canada

Abstract

Emerald Ash Borer (Agrilus planipennis) is an introduced Asian wood boring beetle (family Buprestidae) that is rapidly spreading in North America and poses a significant threat to all North American ash (Fraxinus) species (Herms and McCullough 2014; COSEWIC in prep.). In 2016, the Aboriginal Traditional Knowledge (ATK) Subcommittee of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) solicited the Atlantic Canada Conservation Data Centre (AC CDC) and Donna Hurlburt to co-write a federal status report on Black Ash (Fraxinus nigra) (COSEWIC in prep.). Emerald Ash Borer (EAB) is clearly the largest threat to Black Ash in Canada, already having caused 95% to 99+% ash mortality in heavily susceptible areas (Klooster et al. 2013; 2014). There is, however, good evidence from experimental and modeling studies that cold winter temperatures will limit or prevent the establishment of Emerald Ash Borer in the northern part of Black Ash range (Venette and Abrahamson 2010; Crosthwaite et al. 2011; Sobek-Swant et al. 2012; DeSantis et al. 2013). The extent to which Canadian Black Ash may be protected by cold temperatures is thus a crucial question relative to assessing the species’ federal status. Relatively fine-scale data on climate and Black Ash abundance exist for most of its Canadian range, but a detailed GIS analysis of climate-related limitation of EAB impacts was beyond the scope of the initial COSEWIC status report contract. The COSEWIC ATK Subcommittee thus solicited AC CDC to conduct the analysis described in this report.