The Effect of Biodiversity Loss and Climate Change on Tick-borne Disease

Small land mammals can serve as hosts to vectors of disease, which carry and transmit bacteria (e.g. Borrelia) that pose a potential threat to human health. The loss of large land mammals due to urbanization combined with continuing global climate change could result in a cascading environmental effect impacting other inhabitants of the ecosystem, such as small land mammals, and indirectly causing a change in vector population. By investigating how small land mammals impact their environment through herbivory and serving as hosts for ticks, we sought to demonstrate how mammals can influence prevalence of zoonotic disease, such as Lyme disease.   In this study, we conducted field research at Tejon Ranch in Southern California.  We measured herbivory rates by conducting cafeteria trials in a set of experimental plots located at different microclimates of varying elevations.  The prevalence of ticks was determined through the trapping of small vertebrates such as deer mice and Western fence lizards.  The results showed a higher rate of herbivory at the experimental plots at higher elevation where there was more moisture, providing the small land mammals with the environment to succeed.  Trapping of small vertebrates allowed for the collection of ticks which will be tested for zoonotic diseases.  The low capture rate of small land mammals reflects the current environmental stresses such as drought and season.  These data collected will be used as baseline data in the years to come of this long-term experiment as herbivory rates change with the exclusion of large and small land mammals.