American Society of Naturalists

A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.

“The critical role of infectious disease in compensatory population growth in response to culling”

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Eleanor Tanner, Andy White, Peter W. W. Lurz, Christian Gortázar, Iratxe Díez-Delgado, and Mike Boots (July 2019)

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Using mathematical models we show how culling populations harboring endemic disease can lead to compensatory growth

Wild boar (<i>Sus scrofa</i>).<br />(Credit: Christian Gortázar)
Wild boar (Sus scrofa).
(Credit: Christian Gortázar)

Abstract

Despite the ubiquity of disease in nature, the role that disease dynamics play in the compensatory growth response to harvesting has been ignored. We use a mathematical approach to show that harvesting can lead to compensatory growth due to a release from disease-induced mortality. Our findings imply that culling in systems that harbor virulent parasites can reduce disease prevalence and increase population density. Our models predict that this compensation occurs for a broad range of infectious disease characteristics unless disease induces long-lasting immunity in hosts. Our key insight is that a population can be regulated at a similar density by disease or at reduced prevalence by a combination of culling and disease. We illustrate our predictions with a system-specific model representing wild boar tuberculosis infection, parameterized for central Spain, and find significant compensation to culling. Given that few wildlife diseases are likely to induce long-lived immunity, populations with virulent diseases may often be resilient to harvesting.