Droughts drive outbreak dynamics of an invasive forest insect on an exotic host

• Autores: Lantschner, Maria Victoria; Aukema, Brian H.; Corley, Juan Carlos
• Año de publicación: 2019
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Forest Ecology and Management 433 : 762-770. (February 2019)
• Materia: Insectos Perforadores de la Madera; Sirex; Plagas Forestales; Timber Boring Insects; Forest Pests; Insectos Forestales; Sirex Noctilio; Región Patagónica
• Institución: Instituto Nacional de Tecnología Agropecuaria

Insect outbreaks are among the most important biotic disturbances in forest ecosystems and can exert immense economic and ecological impacts. Understanding the spatio-temporal patterns of eruptive insects can provide insights into the mechanisms driving their dynamics and help predict future responses under climate change. The aims of this study were to analyze the spatio-temporal patterns of outbreaks of the woodwasp Sirex noctilio –a major invasive pest of pines– in an invaded region of South America, to assess the relative importance of density-dependent and density-independent mechanisms on population dynamics, and to identify the primary factors that influence the magnitude of outbreaks. We used tree ring and insect sampling data of more than 1000 trees to reconstruct S. noctilio outbreaks in 29 pine stands across Patagonia-Argentina over a 16-year period. We found marked spatial synchrony in S. noctilio outbreaks at a regional scale. Rates of tree mortality from S. noctilio were influenced by both density-dependent and density-independent factors. The occurrence of S. noctilio outbreaks are triggered by an abrupt increase in drought, which likely increases the availability of susceptible host trees. The damage caused by the outbreaks is determined by stand level variables, closely related with tree stress. Rates of tree mortality decreased over time due to negative density-dependence in S. noctilio populations, likely due to the loss of suitable resources over time. Depicting mechanisms of large-scale tree mortality in ecosystems provides insights to the drivers of forest outbreaks and other factors such as responses to a changing climate.
Estación Experimental Agropecuaria Bariloche
Fil: Lantschner, Maria Victoria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Sistemas Forestales. Grupo de Ecología de Poblaciones de Insectos; Argentina
Fil: Aukema, Brian H. University of Minnesota. Department of Entomology; Estados Unidos
Fil: Corley, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentina