The future abundance of key bird species for pathogen transmission in the Netherlands

Wild birds serve as reservoirs and vectors for many different pathogens and changes in their distribution and abundance due to environmental change will influence disease risk. We study three species which are highly abundant in north-western Europe and which can transmit a wide range of diseases including avian influenza and West Nile virus: blackbirds, mallards and house sparrows. Using the Netherlands as a case study, we created random forest models for predicting the distribution and abundance of these species, both now and in the future. Climate, land use and vegetative cover were all important predictors of bird abundance. The three species had different spatial distributions, largely related to their preferred habitat and food availability. In the future, mallard and house sparrow populations were predicted to increase, while there was little change for blackbirds. Quantifying the consequences of these abundance changes is complicated as there are many factors to consider, however increased pathogen reservoirs will likely increase disease risk and changes in distribution may affect local outbreak risk. The future abundance maps created in this study, and the methods used to create them, will be useful tools for disease modellers and policymakers to estimate future disease risk and to plan accordingly.