Research in disease ecology

Our research on disease ecology focused on the combined effects of habitat alteration and wildlife community structure on the risk of disease outbreaks in the black-tailed prairie dog (Cynomys ludovicianus), a foundation species in western grasslands and a species of conservation concern. This species is susceptible to blood diseases transmitted by fleas, such as the sylvatic plague. Populations (colonies) contracting plague through infective fleas commonly suffer 100% mortality, so predicting the risk of exposure to infective fleas is of utmost importance for the conservation of this species.

Our field research, conducted from 2002-2007, emphasized gathering data to determine the statistical relationships between outbreaks of plague and bartonellosis in black-tailed prairie dogs and in the alternate host community. We gathered data at both regional and local scales on landscape structure and land use, population demography, vector abundance and distribution, and pathogen and disease occurrence.

Our studies revealed that:

  1. Prairie dog population density is significantly higher in urban than rural contexts.
  2. Plague occurrence is influenced by prairie dog colony characteristics, landscape structure and climate.
  3. The magnitude and direction of the effect of prairie dogs on rodent assemblages vary across their geographic range as well as among years.
  4. Prairie dogs significantly affect the abundance and diversity of disease vectors on rodents.
  5. Plague occurrence alters the metapopulation structure of prairie dogs. Selected publications are listed below; see the “Publications” tab for a full list of publications from this project.

Johnson, W.C. and S.K. Collinge. 2004. Landscape effects on black-tailed prairie dog colonies. Biological Conservation 115:487-497.

Collinge, S.K., W.C. Johnson, C. Ray, et al. 2005. Landscape structure and plague occurrence in black-tailed prairie dogs on grasslands of the western USA. Landscape Ecology 20:941-955.

Ray, C. and S.K. Collinge. 2006. Potential effects of a keystone species on the dynamics of sylvatic plague. pp. 204-218 in S.K. Collinge and C. Ray (editors), Disease ecology: community structure and pathogen dynamics, Oxford University Press, Oxford, UK.

Collinge, S.K., C. Ray, and J.F. Cully, Jr. 2008. Effects of disease on keystone species, dominant species, and their communities. Pp. 189-213 in R.S. Ostfeld, F. Keesing and V. Eviner, (eds.), Infectious disease ecology: effects of ecosystems on disease and of disease on ecosystems. Princeton University Press, Princeton, NJ.

Brinkerhoff, R.J., C. Ray, B. Thiagarajan, S.K. Collinge, J.F. Cully, Jr, B. Holmes and K.L. Gage. 2008. Prairie dog presence affects occurrence patterns of disease vectors on small mammals. Ecography 31:654-662.

Bai, Y., M.Y. Kosoy, C.H. Calisher, J.F. Cully, Jr., and S.K. Collinge. 2009. Effects of rodent community diversity and composition on prevalence of an endemic bacterial pathogen – Bartonella. Biodiversity 10(4):3-11.

Brinkerhoff, R.J., S.K. Collinge, C. Ray, and KL. Gage. 2010. Rodent and flea abundance fail to predict a plague epizootic in black-tailed prairie dogs. Vector-Borne and Zoonotic Diseases 10(1):47-52.

Cully, J.F., Jr., T.L. Johnson, S.K. Collinge, and C. Ray. 2010. Disease limits populations: plague and black-tailed prairie dogs. Vector-Borne and Zoonotic Diseases 10(1):7-15.

Cully, J.F., Jr., S.K. Collinge, W.C. Johnson, C. Ray, B. Thiagarajan, D.B. Conlin, and B. Holmes. 2010. Spatial variation in keystone effects: small mammal diversity associated with black-tailed prairie dog colonies. Ecography 33:667-677.