Effects of Biotic and Abiotic Setting on a Host-Pathogen Relationship: How Environmental and Community Characteristics Influence Infection Prevalence and Intensity of Amphibian Chytrid on California's Central Coast

摘要: Author(s): Hemingway, Valentine | Advisor(s): Raimondi, Peter Abstract: In the face of swift anthropogenic change, it is essential to examine broad ecological context for species concern using a variety approaches in order understand their interactions natural context. Host-pathogen relationships offer close interaction how each are acted upon by biotic and abiotic conditions. Batrachochytrium dendrobatidis, an emerging infectious disease amphibians, has been implicated with wholesale loss marked declines amphibian across globe, thus understanding its dynamics hosts complex, environments key area conservation focus.For this dissertation, I tested importance various factors relationship between B. dendrobatidis three co-occurring hosts, as well metrics host physiological health. Chapter 1, ranked environmental conditions that favor success two native one introduced tadpole species. found top models favoring infection included: a) positive community diversity, b) elevated infected species, c) varying, but strong assorted vegetative cover types. 2, asked which factor, Bd infection, predator best explained including, body condition, total white blood cell count, neutrophil lymphocyte ratio, tadpole. The most important predicting condition varied markedly Tadpole was positively correlated diversity Lithobates catesbeiana, negatively Rana draytonii, index Pseudacris regilla. While only factor impacted ratios bullfrogs, counts, again saw difference way different responded stressors environment. driver elevating counts P. regilla, while had effect R. draytonii. Predator negative on L. catesbeiana. This responses useful from management perspective, may allow practitioners shift habitat suitability interest. Given differences amphibians respond, handful concrete recommendations emerge:1. Decrease decreasing species; provide ponds specialized site, in-pond maintaining site2. Increase sunning sites draytonii regilla maintain complexity3. Create or smaller, exposed, ephemeral 4. larger, shallower, Improve water quality draytonii5. controlling particularly bullfrog tadpoles, adults, fishMy dissertation demonstrates taking approach designing studies combining perspectives such pathogen stress, into account suite likely interacting factors. Broad can help avoid spurious decisions given limited time resources protect rapidly declining