Biology: House Sparrows & Leopard Seals
Azana Best, azana_best1@baylor.edu
Baylor University, with Dr. Sarah Kienle
Biology
Comparison of stable isotope analysis values of various leopard seal tissues
The rapidly changing climate is causing a shift in the ecosystem of the Southern Ocean . Leopard seals (Hydruga Leptonyx), are apex predators of the Southern Ocean that heavily control the structure of the Southern Ocean food web. Leopard seals are one of the least studied apex predators on Earth, due to their remote habitat, solitary nature, and aggressive behavior. Researchers opportunistically collect samples from leopard seals to study their diet (stable isotopes; bulk nitrogen and carbon), leading to a variety of different types of archived samples. However, the comparison of these tissues and how well they represent the individual’s diet is unknown. Our objective is to compare the isotopic composition of each tissue to further inform us on leopard seal diet and similarities and differences between the tissues (whiskers, hair, blood, claws, blubber) from the same individuals. The isotopic measurement of several tissues from the same individual can provide short-, intermediate-, and long-term dietary information. Our preliminary data shows an association between two very distinct tissues, blood and whiskers. Additionally, we investigated the variation of nitrogen and carbon isotopes along the length of whiskers, providing important base-line information on the variance in isotope values from seals feeding on heterogeneous diets. Our next steps are to analyze the isotopic composition of the remaining tissues and assess the variation between the tissues based on their different turnover rates. These results will allow more accurate dietary reconstructions on the basis of isotopic analysis of the tissues of seals and other marine mammals.
DiDiAlice Coker, dcoker@nevada.unr.edu
University of Nevada, Reno, with Dr. Jenny Ouyang
Biology
How Artificial Light at Night Affects the Behavior and Fitness of House Sparrows
Human activities change habitats faster than local species can adapt, threatening many with extinction. Loss of biodiversity degrades ecosystem functioning through the loss of ecosystem services. Urbanization is one such activity presenting novel stressors that reduce survival and reproduction. One stressor is light pollution which interferes with natural light-dark cycles and may disturb sleep and wake cycles, perhaps most noticeably in city-dwelling birds. Abnormal light exposure through artificial light at night may perturb behavioral rhythms important for reproductive success (fitness) and survival. It is currently unknown what long-term effects abnormal light has on survival and fitness. This study will inform how artificial light at night correlates with fitness in adult house sparrows (Passer domesticus). I hypothesize that artificial light at night dysregulates behavioral rhythms thereby imposing long-term negative effects on fitness. I will assess nocturnal activity and parental effort as proxies for behavior, while offspring survival estimates will inform fitness. Nocturnal activity will be acquired by tracking the movement of subjects with radio transmitters. Parental effort will be the rate at which parents feed chicks, determined through observation of nests. Offspring survival will be estimated using the number and body condition of offspring, calculated using weight and tarsus length. Measures will be compared among three sites around Reno, Nevada exposed to low, medium, and high intensities of artificial light at night. Establishing the strength of the relationship between artificial light at night and fitness will support the implementation of effective wildlife conservation measures.