Assessing a landscape barrier using genetic simulation modelling: implications for raccoon rabies management

Area of Science:

• Ecology and Evolutionary Biology
• Epidemiology
• Conservation Genetics

Background:

• Landscape features significantly influence animal movement and the spatio-temporal dynamics of infectious diseases.
• Assessing the impact of barriers like rivers is crucial for wildlife disease risk management, particularly for diseases like rabies.

Purpose of the Study:

• To quantify the barrier effect of the Niagara River on raccoon (Procyon lotor) movement.
• To evaluate the risk of raccoon rabies transmission from New York State to Ontario, Canada.
• To integrate genetic data from simulations and field samples for enhanced disease spread modeling.

Main Methods:

• An individual-based, spatially explicit computer model simulated raccoon population expansion across the Niagara River.
• Genetic population structure was analyzed using mitochondrial DNA haplotypes, phi ST genetic distance, Mantel tests, and gene diversity.
• Model outputs were compared with genetic data from 166 field-sampled raccoons to calibrate the river's barrier effect.

Main Results:

• The "best fit" model indicated the Niagara River prevents approximately 50% of raccoon crossing attempts.
• Founder effects were the primary driver of genetic structure in the colonizing population.
• Increased river barrier effect correlated with decreased genetic diversity in the raccoon population.

Conclusions:

• The Niagara River acts as a significant barrier, reducing potential cross-river rabies infection.
• Genetic data from simulations and field samples effectively calibrate landscape barrier effects on gene flow.
• This approach enhances the investigation and control strategies for wildlife infectious diseases.