Murray State University
The Effects of Habitat Fragmentation on the Health of White-footed Mice (Peromyscus leucopus)
Institution
Murray State University
Faculty Advisor/ Mentor
Terry Derting
Abstract
Anthropogenic disturbances leading to white-footed mouse habitat fragmentation may affect the health of animals in disturbed areas. To determine those effects, if any, we tested the null hypothesis that anthropogenic disturbances have no effect on immunocompetence, stress level, and masses of gastrointestinal or reproductive organs. We studied two types of habitat patches; those disturbed by human activities, specifically agriculture and urbanization, and those that were undisturbed. Adult males were trapped live. Blood samples and white blood cell counts (WBC) were prepared following capture. To challenge humoral and cell-mediated branches of the immune system, subjects were injected with sheep red blood cells (SRBC) the morning after capture and phytohemagglutinin (PHA) seven days later. Final blood sampling and dissection were performed on the eighth day. Mice from disturbed habitats had a greater cell-mediated immune response, but a reduced humoral immune response compared with those from undisturbed habitat. Mice in disturbed habitats also had a lower hematocrit, and tended to have a smaller increase in WBCs in response to SRBC injection. Mice caught in disturbed habitats also tended to have heavier mass of adrenal glands, and greater stomach and caecum masses. Masses of reproductive organs and corticosterone levels showed no significant differences. We concluded that white-footed mice from disturbed habitats exhibited reduced humoral immune function compared with animals in undisturbed habitat. In contrast, cell-mediated immunity, diet quality and stress level were not adversely affected by anthropogenic disturbances. These results suggest that habitat fragmentation and human disturbances have specific, rather than general, effects on health of white-footed mice.
The Effects of Habitat Fragmentation on the Health of White-footed Mice (Peromyscus leucopus)
Anthropogenic disturbances leading to white-footed mouse habitat fragmentation may affect the health of animals in disturbed areas. To determine those effects, if any, we tested the null hypothesis that anthropogenic disturbances have no effect on immunocompetence, stress level, and masses of gastrointestinal or reproductive organs. We studied two types of habitat patches; those disturbed by human activities, specifically agriculture and urbanization, and those that were undisturbed. Adult males were trapped live. Blood samples and white blood cell counts (WBC) were prepared following capture. To challenge humoral and cell-mediated branches of the immune system, subjects were injected with sheep red blood cells (SRBC) the morning after capture and phytohemagglutinin (PHA) seven days later. Final blood sampling and dissection were performed on the eighth day. Mice from disturbed habitats had a greater cell-mediated immune response, but a reduced humoral immune response compared with those from undisturbed habitat. Mice in disturbed habitats also had a lower hematocrit, and tended to have a smaller increase in WBCs in response to SRBC injection. Mice caught in disturbed habitats also tended to have heavier mass of adrenal glands, and greater stomach and caecum masses. Masses of reproductive organs and corticosterone levels showed no significant differences. We concluded that white-footed mice from disturbed habitats exhibited reduced humoral immune function compared with animals in undisturbed habitat. In contrast, cell-mediated immunity, diet quality and stress level were not adversely affected by anthropogenic disturbances. These results suggest that habitat fragmentation and human disturbances have specific, rather than general, effects on health of white-footed mice.