Jumping in with Both Feet: Exploring Factors that Shape Juvenile Amphibian Movement

Investigation into how animals move within the landscape is important for both understanding of ecological processes and conservation management. Animal movement is important in shaping life history transitions, demographics, individual fitness, and species distributions. However, as landscapes become increasingly affected by human activities, movement becomes important as species navigate landscapes experiencing habitat fragmentation, isolation, and degradation. To address how human activities are changing animal movement, there is a need to understand the movement patterns and behaviors of an animal during early life stages. Amphibian species often have bi-phasic life histories with aquatic larval tadpoles and terrestrial juveniles and adults. All dispersal between populations and across the landscape occurs during these terrestrial stages. In particular, the juvenile life stage is thought to be an important dispersal stage, but has been understudied in amphibian biology. In this dissertation, I performed several projects investigating the factors that shape juvenile movement and how aquatic conditions before metamorphosis may express latent effects on these behaviors. I also examined how these observed behaviors may affect the population connectivity in future climates. The movement behavior of juveniles was strongly influenced by the identity of the species, environmental conditions, and individual size. Aquatic environments expressed latent effects on juvenile amphibian size, but not directly on movement behavior. Terrestrial environmental conditions were also important with dry terrain and low ambient humidity associated with increased movement distances. Using an individual-based simulation model, the observed effect of environmental conditions on movement behavior also reduced population connectivity in future climate conditions, when compared to current climates. Movement ecology is a growing field, and through the application of various tools and techniques that are being developed we can fill in the gap of knowledge around amphibian terrestrial movement

Starting on the Right Foot: Carryover Effects of Larval Hydroperiod and Terrain Moisture on Post-metamorphic Frog Movement Behavior

Changing patterns of precipitation and drought will dramatically influence the distribution and persistence of lentic habitats. Pond-breeding amphibians can often respond to changes in habitat by plastically shifting behavioral and developmental trait response. However, fitness tradeoffs inherent in life history strategies can carry over to impact development, behavior, and fitness in later life stages. In this experiment, we investigated carryover effects of hydroperiod permanence on the movement behavior of newly-metamorphosed juvenile Northern Red-legged Frogs (Rana aurora). Frogs were raised through metamorphosis in mesocosms under either permanent or ephemeral hydroperiod conditions. After metamorphosis, individuals were removed from the mesocosms, measured, uniquely tagged with elastomer, and moved to holding terrariums. Movement behavior was quantified under two terrain conditions: a physiologically-taxing, dry runway treatment, or a control, moist runway treatment. Individuals were given 30 min to move down the 1 × 20m enclosed structure before distance was measured. We applied a hurdle model to examine two distinct components of movement behavior: (1) the probability of moving away from the start location, and (2) movement distance. We found that hydroperiod condition had an indirect carryover effect on movement via the relationship between individual size and the propensity to move. Individuals from ephemeral mesocosm conditions metamorphosed at a smaller size but showed increased growth rates as compared to individuals from permanent hydroperiod conditions. Individual snout-vent length and runway condition (moist or dry) were significant predictors of both aspects of movement behavior. Larger individuals were more likely to move down the runway and able to move a farther distance than smaller individuals. In addition to the influence of size, dry runway conditions reduced the probability of individuals moving from the start location, but increased the distance traveled relative to the moist runway. The demonstrated cumulative impact of stressors suggests the importance of addressing direct, indirect, and carryover effects of stressors throughout ontogeny

Comparing anuran performance and movement

Movement in an important component of an animal’s life cycle when it relies on both aquatic and terrestrial habitats. When multiple species overlap in the use of these habitats, they rely on other methods to reduce competition for shared resources. This dataset measured the jumping performance and movement behavior of three anuran species as juveniles. By relating their movement behavior to physical and behavioral attributes, we worked to understand the factors that determine an individual’s movement, and how these factors change between species. The three species in this dataset represent three distinct groups of anuran species. In the Cascade mountains these species rely on the same breeding habitat and emerge in the same time frame. This project aimed to examine differences in their movement behavior and how morphological and performance abilities impact their movement

A recreation ecology perspective on the COVID-19 (SARS-CoV-2) pandemic: Potential parks and protected area impacts relating to visitor spatial use, terrestrial flora and fauna, and management

Measures to limit the spread of COVID-19 require changes in the ways that people travel, gather, and recreate in outdoor spaces. In 2020, to limit human-to-human transmission of COVID-19, US park and protected area managers at all levels of governance implemented closures and restrictions on the types of activities and facilities available for public use. At the same time, the US Centers for Disease Control and Prevention outlined suggestions for social distancing, wearing face masks, and limiting travel and group sizes for social gatherings. This thought piece explores potential shifts in park accessibility and human behaviors that may lead to cascading impacts on visitor spatial use, terrestrial flora and fauna, and park management. We discuss potential changes in visitor spatial behavior and possible subsequent ecological impacts on terrestrial flora and fauna. Additionally, we connect these topics with management implications and emphasize adaptive management and continued monitoring to address current and future pandemic-related issues. We provide park managers, researchers, and other professionals with expected social and ecological implications resulting from managerial and behavioral shifts in response to the COVID-19 pandemic. Furthermore, we suggest management approaches to address and monitor these impacts. This information can help shape how park managers respond to the ongoing pandemic and future human health issues that impact park visitors and flora and fauna. Finally, we offer suggestions for where prospective researchers can direct their focus, especially in areas where recreation ecology and human disease management intersect