Investigation of environmental correlates of Ambystoma tigrinum Ranavirus in two Arizona amphibian species

Cooney, Kathryn Anne (2021) Investigation of environmental correlates of Ambystoma tigrinum Ranavirus in two Arizona amphibian species. Masters thesis, Northern Arizona University.

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Abstract

Diseases have been linked to worldwide amphibian declines, with Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), and viruses in the genus Ranavirus, causing mass mortality events. Despite the clear impact of disease on some amphibian populations, few studies have investigated the relationship between local environmental conditions and the spatial and temporal trends of pathogen infection. Trends and dynamics of disease occurrence and prevalence in host species are not well understood despite seasonality and habitat differences being linked to spatial and temporal disease variability. In this study, we investigated abiotic and biotic environmental conditions that correlate with the occurrence and the prevalence of Ambystoma tigrinum virus (ATV) in western tiger salamanders (Ambystoma mavortium) and Chiricahua leopard frogs (Rana chiricahuensis). We found that for both species, larger site areas resulted in lower prevalence of ATV. Ambystoma mavortium also had higher prevalence in 2019 compared to 2020. Additionally, prevalence tended to increase over each season, with late-season (post-June) prevalence being significantly higher than earlier in the year. Sites with higher amphibian species richness were also found to have higher ATV prevalence. Also, R. chiricahuensis had higher ATV prevalence at sites that also had higher turbidity. Our results generally concur with the few other studies of Bd and Ranavirus, which also show the importance of various environmental conditions related to epizootics. These results show that ATV infection dynamics may be driven by different environmental factors in different host species. Knowledge of wildlife disease trends can be beneficial to management agencies for the conservation of at-risk species, in this case especially for threatened R. chiricahuensis and endangered Sonoran tiger salamanders (Ambystoma tigrinum stebbinsi). Future research should further explore the relationships between disease, various amphibian host species as well as life stages within species, and environmental conditions including abiotic and biotic conditions.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Chiricahua leopard frog; ranavirus; Western tiger salamander
Subjects:	Q Science > QL Zoology
MeSH Subjects:	C Diseases > C02 Virus Diseases C Diseases > C03 Parasitic Diseases
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited:	01 Feb 2022 19:04
Last Modified:	01 Feb 2022 19:04
URI:	https://openknowledge.nau.edu/id/eprint/5625

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