The results of my research suggest that tadpoles of the Western
toad (Bufo boreas) and the Cascades frog (Rana cascadae) display an
alarm response to chemicals from injured conspecific tadpoles.
Furthermore, results suggest that the Bufo boreas alarm response can
be elicited by a natural predator when it feeds on...
Ultraviolet-B radiation (UV-B) has been suggested as a factor contributing to global amphibian population declines. While ambient UV-B levels damage the eggs and embryos of some amphibian species, few studies have addressed how UV-B affects other life history stages or sublethal responses. My dissertation focuses on (1) investigations of sublethal...
Emerging infectious diseases are increasing globally and are a threat to human, wildlife, and ecosystem health. The emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), or amphibian chytrid fungus, is associated with worldwide amphibian population declines and extinctions. Bd has been found on every continent where amphibians exist and has been documented...
Rapid rates of biodiversity loss have supported the notion that Earth is experiencing a sixth major extinction event. The causes of worldwide biodiversity loss are multifaceted and context dependent. One of the most prominent groups experiencing population declines and extinctions are amphibians. Several pathogens and their associated diseases are especially...
The earth is undergoing a “biodiversity crisis” characterized by loss of populations, species, genetic diversity, and ecosystem services. Part of this crisis consists of population declines, extinctions, and increased incidence of deformities in amphibians. It is unknown whether deformities contribute to these declines. Many cases of population declines in amphibians...
The tadpoles of several anuran species with groupforming
larvae are relatively unpalatable to many of
their potential predators. To more fully understand the
role of palatability and its relationship to group
formation as an antipredator defense in anuran amphibian
larvae, I investigated the palatabilities of the larvae
of three species...
Juvenile T. townsendii were tested at 55-62 days of
age to determine whether 1) they could distinguish kin from
non-kin and 2) whether this ability was based on
familiarity or on genetic relatedness. Seventy-three pups
were observed in 68 pairwise tests. The frequencies and
durations of 8 behaviors as well...
Some parasites may modify the behavior of their
hosts. Altered behaviors may: 1) benefit the host in
that they defend against the pathogen, 2) benefit the
pathogen and represent manipulations of the host
response, and 3) benefit neither the host or the
pathogen and simply be a product of the...
Ultraviolet-B radiation (UVB) is an abiotic stressor in both terrestrial and aquatic systems. The stratospheric ozone layer, depleted due to anthropogenic activities and the cause of elevated UVB at earth's surface over the last four decades, is predicted to recover by 2065. However, UVB levels in aquatic systems may continue...
The current rate of global biodiversity loss and extinctions is unparalleled and a major concern. Freshwater organisms are facing particularly rapid rates of biodiversity loss. Amphibians, which require an aquatic environment for part of their life cycle, are one of the most vulnerable vertebrate groups. Amphibians are experiencing population declines,...
