US Geological Survey


Date of this Version



Published in Weber, Samantha, and David Harmon, eds. 2008. Rethinking Protected Areas in a Changing World: Proceedings of the 2007 GWS Biennial Conference on Parks, Protected Areas, and Cultural Sites. Hancock, Michigan: The George Wright Society.


The threat of invasive species to natural areas presents enormous challenges, but there are opportunities for working toward solutions, often in conjunction with agricultural and forestry perspectives. There is a growing awareness of the danger to botanical biodiversity and conservation from “emerging infectious diseases” that have increased in incidence, geographical distribution, or host range/pathogenicity; have newly evolved characteristics; and/or have been newly discovered (Anderson et al. 2004). There is a heightened concern for forest health due to accelerating worldwide movement of plant pathogens (e.g., with ineffective quarantine measures) that negatively affect both biodiversity and commercial forestry (Wingfield 2003). An important related concept is that of the ability of fungi to jump to new hosts following anthropogenic introduction. Native hosts are exposed to pathogens with no coevolved recognition or defense mechanism, and microevolution toward increased virulence of introduced pathogens can result (Wingfield 2003; Slippers et al. 2005). The rust fungus Puccinia psidii (Basidiomycota, Uredinales: Pucciniaceae), a species first documented to have jumped from native guava (Psidium guajava, Myrtaceae) to introduced Eucalyptus spp. (Myrtaceae) in Brazil in 1912 (Coutinho et al. 1998) is an extremely important example of this phenomenon (Wingfield 2003; Slippers et al. 2005). Such threats have typically been underestimated by quarantine authorities worldwide, largely due to a lack of understanding of the taxonomy and ecology of the fungi involved (Wingfield 2003). For example, Coutinho et al. (1998) stated: “A detailed taxonomic study is needed to determine the host range and geographical distribution of P. psidii. It is still not certain whether more than one species of Puccinia is capable of infecting members of the Myrtaceae. Comparisons at the molecular level would be particularly useful in this regard.”