Marilyn Ramenofsky, Ph.D. - US grants

The University of California Davis is awarded a grant to acquire and deploy specialized receiver/antenna units that will enable automated animal telemetry at the Quail Ridge Natural Reserve using the existing wireless communications towers. The project will also enhance the wireless communications at the UC Davis West Campus Reserve (Putah Creek) and establish a compatible telemetry receiver network at that site. The proposed system is compatible with a diverse range of available radio transmitter devices and will allow researchers visiting the sites to pursue continuous, real-time animal movement and physiological studies that would be technically difficult or impossible in settings without an extensive off-grid communications infrastructure. A key objective of the automated telemetry program at Quail Ridge will be the integration of animal movement information from the reserve into the NSF-funded Movebank database.

Automated animal telemetry systems provide an unparalleled opportunity to study animal movement, interaction, and physiology. With such systems, signals from tiny transmitters attached to individuals are detected by a network of receivers, which interpret signal strength and direction to determine real-time animal location and activity; the transmitters may also communicate physiological parameters such as body temperature and heart rate. Data collected by the network are then streamed to the web, where researchers, instructors and students have instant access. In spite of the enormous potential of automated telemetry networks, very few operational systems exist. The daunting investment necessary to establish such a system, given the challenges of constructing receiver towers, providing electric power, and building a functional communications network in a remote setting, has greatly limited their implementation.

Most vertebrates live more than one year and are subjected to varying degrees of seasonal changes in diverse habitats. Animals must also cope with unpredictable events that include stresses from severe weather events, predators and recently, human disturbance, pollution, global climate change etc. Changes in morphology, physiology and behavior that underlie coping mechanisms for predictable and unpredictable environmental changes are regulated by neuroendocrine and endocrine secretions that in turn are triggered by environmental signals. Except for effects of photoperiod, relatively little is known about how environmental signals are perceived and transduced into neuroendocrine secretions. This project is to determine how animals in their natural habitat perceive environmental cues and how this information is processed resulting in responses. The work will involve both field and laboratory approaches that also provide an ideal training opportunity for undergraduate and graduate students. Such an approach is timely given the impact of global change and how organisms in general may be able to cope. Fieldwork will address the degree of seasonality, behavioral modulation and responses to acute stresses in populations of songbirds at comparable latitudes and altitudes in North and South America. Laboratory studies will focus on mechanisms at cell and molecular levels. What environmental cues are important, how are they perceived and transduced into hormone secretions, and how do those hormones then act are the focus of this project. In addition, the PI has developed an environmental endocrinology course for undergraduate and graduate students (including international courses)and leads a NSF research coordination network.

As a consequence of global warming, arctic North America has been ?greening? over the past several decades, with increases in relative abundance and size of shrubs documented in numerous locations. Much of the research on this topic examines how this shift toward more woody species affects element cycling, particularly carbon, with potential feedbacks to the atmosphere regionally and globally. To date, the response of higher trophic levels to such shifts in vegetation in the Arctic has not been well studied. One group that has been almost completely ignored is migratory songbirds; they have a complex relationship with shrubs that provide both shelter and food, both of which are directly affected by weather patterns. This research will characterize the interactions between tundra vegetation and migratory songbirds in habitats that differ in shrub dominance for five consecutive growing seasons that will differ in timing and severity of weather events. The team will 1) identify and characterize interactions between shrub dominance and weather to determine how these affect food and shelter availability for migratory songbirds; 2) examine how reproductive success of populations of two songbird species responds to variation in both shrub dominance and timing of spring snowmelt, and; 3) measure how both variation in shrub dominance and timing of spring snowmelt affect composition and size of the entire songbird community. The multi-year approach will allow for examination of how interannual variability in arctic seasonality, particularly the timing of snowmelt, impacts songbird communities. Because the increasing shrub dominance is occurring too slowly for organisms to respond to during the time period of a grant, the researchers will examine habitat usage in open tundra plots, moderate shrub dominance plots, and high shrub dominance plots, at each of four study sites on the North Slope of Alaska. These include Atigun Valley, one of the first tundra stops made by migratory songbirds as they travel north, and at Toolik Lake, farther north, including two additional sites farther north to increase the spatial scale of sampling. In five project years, they will sample intensively at all four field sites to investigate spatial and temporal variation in plant resources, arthropod abundance, songbird community composition, and the arrival, settlement and reproductive success of two songbird species. During five years they hope to capture a range of interannual variability in weather, onset of spring snowmelt, and biotic responses to provide and understanding of current relationships and to predict how future changes in climate and vegetation may affect these organisms. They also intend to verify the use of remote techniques for monitoring bird community attributes via bioacoustic recordings for conducting automated bird community censuses.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

Each autumn and spring a rush of wings fill the night skies as birds migrate between distinct locations for breeding and the other for over-winter survival. However, recent reports indicate that the numbers of migratory species are rapidly declining worldwide. Reasons for these declines have been attributed in general to global environmental change but few specifics are known. Even though bird migration has been appreciated for hundreds of years, little is understood of how environmental conditions influence regulation of the physiological and behavioral mechanisms of migration. Another enigma is that even though spring and autumn migrations appear similar in distance and terrain covered, the climatic conditions and physiological and behavioral states of migrants in the two seasons differ. The studies proposed are designed to determine the mechanisms of both spring and autumn migrations in a long-distance migrant, the Gambel's White-crowned Sparrow. Comparisons are drawn with a close relative and non-migrant, Nuttalls White-crown Sparrow. Intraspecific comparisons of this nature are rare and vital for determining the adaptations of migrants. Specifically, how do such factors such as photoperiod (day length) affect the behavior, physiology and biochemical changes required to migrate long distances (6000 km)? For example, migrants must increase appetite to achieve a temporary state of obesity and increase aerobic capacity and endurance of flight muscles, etc. to complete each migratory bout. Studies will test how the spring increase in day length affects feeding, fattening and skeletal and heart muscles. Comparisons will be run in autumn, when day length is declining. Results from these studies may provide intricate clues for determining how the environment affects migrants in order to slow or even prevent further loss of this remarkable adaptation.