Title:
A CASCADE OF EFFECTS CAUSES A POPULATION CRASH IN RESIDENT MAMMALS

Authors:
David D. Leimbach

Abstract:
We spent the late-summer and fall of 2011 through 2013 studying the habitat use and population characteristics of mammals located on two tracts of farm ground at the Prairie for Biodiversity research site in Decatur, Illinois. During the study, population crashes were observed in Peromyscus maniculatus and Microtus ochrogaster. During the first year of the study, a seemingly in hospitable (urban) agricultural area revealed a diverse population of inhabitants. mammal populations had been observed. In the third year, population numbers of Peromyscusmaniculatus and Microtus ochrogaster had also plummeted. Blood samples obtained from the carcasses of deceased animals revealed a population impacted by disease. Due to an initial population explosion from a pulsed resource, the physical effects of enduring the third year of a drought cycle adversely impacted the mammal populations. Resident mammals shifted their energy into survival rather than immune function, which allowed their immune systems to become compromised by parasitic invaders and hastened the population crash.