Climate Change, Biosecurity and Migratory Insect Pests: Integrating Population Dynamics with ‘Over the Horizon’ Invasion Ecology

Migratory insect pests can pose recurrent biosecurity risks as pests disperse from source areas into seasonally vulnerable regions. Under a changing global climate, pest risks may alter as migration patterns shift; for example changes in the timing of migration events to higher latitudes. Future pest impacts are likely to be influenced by a combination of both direct and indirect factors, such as changes in pest demography, geographical ranges and host growing conditions. Understanding such complex future scenarios requires a simulation approach to project the implications for biosecurity.

The CRCNPB 10071 project has focused on the case study of the population dynamics of the aphid Rhopalosiphum padi in several agricultural landscapes of Australia. The spatially-explicit aphid-wheat-CYDV model demonstrates a novel integration of (1) a coupled spatial population dynamics model of host-disease-vector; (2) airborne pest dispersal simulation; (3) climate change scenarios to estimate future risk from existing pest species in the Australian agricultural environment.

Here we present successful simulation results from the coupled model in Spatial Dymex to examine impacts of BYDV and changing CO2 levels on the aphid-wheat-virus system, as well as the spatial simulation of aphid dispersal across the landscape into wheat crops from their over-summer grassland hosts.

This work carried out by the CRCNPB 10071 project has been an important precursor to the development of a bid for future CRC work on biosecurity threats in Australia via wind-borne dispersal.