Determining the role of density-dependent effects in disease induced population impacts

Emerging infectious diseases have contributed to the loss of biodiversity and threaten conservation efforts across the globe. Managing infectious diseases can be challenging in wildlife, often due to the complex nature of pathogen transmission in muti-host systems that can lead to varied decline and recovery patterns. Common disease management strategies focus on the reduction of pathogen transmission at low host densities to be effective. Density-dependent contact rates are generally assumed to be the mechanism driving these decline patterns. However, other density-dependent processes that influence transmission probability could also influence mortality in a density-dependent manner. Here we examine the processes by which population density contributes to the observed declines of bats infected with white-nose syndrome, a fungal disease that has decimated bat populations across North America. We evaluated the contribution of both density-dependent transmission rates and density-dependent environmental exposure on pathogen prevalence and host population declines. Our analyses indicate that the importance of population density varies depending on the phase of the epidemic, and that density-dependent declines are not observed in years when we see density-dependent transmission. Instead, we find that the amount of pathogen a host is exposed to in the environment is density-dependent and likely contributes to the observed patterns of decline. This research contributes to our general understanding of the role of density-dependent processes in disease dynamics and can help inform when certain disease mitigation efforts will be most effective.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biological Sciences

Department dc:contributor.department

Biological Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2026

Author dc:creator

• Newell, Rose Gabrielle

Chair dc:contributor.committeechair

• Hoyt, Joseph R.

Committee members dc:contributor.committeemember

• Hawley, Dana Michelle
• Langwig, Kate Elizabeth

• Disease ecology
• white-nose syndrome
• density dependence

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:46339

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/143650