Graduation Date
Winter 2003
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Wildlife
Committee Chair Name
Cynthia J. Zabel
Committee Chair Affiliation
Cal Poly Humboldt Faculty or Staff
Second Committee Member Name
Timothy E. Lawlor
Third Committee Member Name
T. Luke George
Keywords
x
Abstract
Forestry practices may indirectly influence the ecological maintenance of zoonotic disease agents by their direct impacts on rodent community structure and the relative abundance of their associated ectoparasites. Relative abundances of three species of forest rodents and their ticks were compared among four types of stands within the Hoopa Valley Indian Reservation in northwestern California, (USA). The stands were characterized by age since last harvest and silvicultural treatment. Two stand types were harvested 20 to 25 years prior to sampling while the other two stand types were harvested 35 to 40 years prior to sampling. Additionally, each age category was further characterized as having received thin and release silvicultural treatment post harvest or as having received no additional treatment post harvest. Eight sites, two sites per stand type, were surveyed during the summers of 1999 and 2000. Within each site, small mammals were live-trapped for six consecutive nights and upon initial capture sedated for the collection of ticks. Within my study grids, populations of Peromyscus truei nearly doubled, Neotoma fuscipes reduced nearly by half, and Tamias senex remained relatively constant between the 1999 and 2000 summer field seasons. The prevalence of infestation of immature Ixodes pacificus was lower during 2000 by nearly 61 % on both Nfuscipes (1999: 56%; 2000: 22%) and T. senex (1999: 82%; 2000: 32%) and by 51 % for P. truei(1999: 53%; 2000: 26%). However, in 2000, mean intensities of immature I. pacificus increased for
P. truei (1999: 2.0 ticks/infested animal; 2000: 2.5 ticks/infested animal) while intensities on both N. fuscipes (1999: 3.27 ticks/infested animal; 2000: 1.8 ticks/infested animal) and T. senex (1999: 5.73 ticks/infested animal; 2000: 2.13 ticks/infested animal) decreased. Based on differences in rodent captures between stand types, thin and release timber management was correlated with changes in populations of N. fuscipes and T. senex. In addition, infestation levels of immature I. pacificus were greater on all three rodent species in the younger, thinned stands. Differences in rodent captures between stand ages were significant for P. truei and T. senex. Based on these results, there was a relationship between forest disturbance and differences in patterns of abundance of forest rodents and their ectoparasites. These results suggest that timber management practices may affect forest rodent communities, which may, in tum, affect the prey base for forest carnivores and the maintenance of zoonotic disease agents. IV P. truei (1999: 2.0 ticks/infested animal; 2000: 2.5 ticks/infested animal) while intensities on both N. fuscipes (1999: 3.27 ticks/infested animal; 2000: 1.8 ticks/infested animal) and T. senex (1999: 5.73 ticks/infested animal; 2000: 2.13 ticks/infested animal) decreased. Based on differences in rodent captures between stand types, thin and release timber management was correlated with changes in populations of N. fuscipes and T. sen ex. In addition, infestation levels of immature I. pacificus were greater on all three rodent species in the younger, thinned stands. Differences in rodent captures between stand ages were significant for P. truei and T. senex. Based on these results, there was a relationship between forest disturbance and differences in patterns of abundance of forest rodents and their ectoparasites. These results suggest that timber management practices may affect forest rodent communities, which may, in tum, affect the prey base for forest carnivores and the maintenance of zoonotic disease agents.
Recommended Citation
Whitaker, Deborah A., "Relation of Thin and Release Timber Management Practices to Abundance of Woodrats, Chipmunks, Mice, and Ticks Within the Hoopa Valley Indian Reservation" (2003). Cal Poly Humboldt theses and projects. 2622.
https://digitalcommons.humboldt.edu/etd/2622