Parasites and Hormones as Non-invasive Bioindicators of Ecophysiology in Carnivores
Date
2013-04-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Non-invasive measures for investigating physiological responses provide useful tools for understanding how wildlife responds to environmental change. The central and north coasts of British Columbia, Canada, comprise one of the most intact ecosystems in the world; however rapid increases in large-scale human activities, including the threat of oil transport by tankers, could affect ecological processes. I used two biomarkers of physiological responses to investigate how wildlife might be affected by increased or altered patterns in economic activities.
I focussed first on the possibility that environmental change could introduce new parasites or alter existing parasite-host dynamics. By examining larval stages of parasites in wolf feces, I found that most parasites reflected seasonal and spatial patterns in wolf trophic interactions. As a complementary approach, I studied micro- and macro-parasite exposure in dogs as sentinels for wild canids and found that they had been exposed to micro-parasites common in canids elsewhere in North America. Results from dogs and wolves reflected positively the health of their environment and provide a baseline for monitoring against future change.
Widespread salmon declines pose an additional concern for coastal ecosystems, particularly for large carnivores whose fitness is linked with salmon consumption. To investigate how these declines affect bears, I examined stress and reproductive hormones, dietary salmon estimates, and spatial data on salmon abundance. Cortisol and testosterone measurements in bear hair—which reflect cumulative endocrine activity over a 6-month period—varied in relation to salmon consumption and abundance, suggesting that salmon declines might lead to nutritional stress and/or social instability due to competition for salmon. Moreover, trends differed between grizzly and black bears, presumably reflecting their different nutritional requirements, social densities, and habitat use.
An underlying theme was to advance and apply non-invasive research methods. Through several collaborations, I combined morphological techniques with genetics to identify larval stages of parasites in feces. I also validated assays to measure cortisol, testosterone, and progesterone in hair and applied the assays to test whether hormone levels differed in two populations of wolves. Collectively, these studies provide novel understanding of how socio-ecological conditions affect wildlife.
Description
Keywords
Forestry and Wildlife, Ecology, Parasitology
Citation
Bryan, H. (2013). Parasites and Hormones as Non-invasive Bioindicators of Ecophysiology in Carnivores (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27255