Collaborating PIs: Natalie Boelman, Lamont-Doherty Earth Observatory, Columbia University Laura Gough, University of Texas, Arlington John Wingfield, Co-PI University of California, Davis Our project extends beyond changes in vegetation, and considers the cascade of changes that is triggered when Arctic vegetation and seasonality are altered. As highlighted by the Arctic Climate Impact Assessment (ACIA), in contrast to plants, the response of animal populations to simulated or current climate change has been drastically understudied in the Alaskan interior and much of the Arctic. We were funded by the US National Science Foundation's Office of Polar Programs (NSF-OPP) for five years (2010-2014), to study the effects that warming-induced increases in shrub dominance and changing seasonality will have on migratory songbirds in Alaskan Arctic tundra. We are working to identify and characterize the interactions between shrub dominance and weather to determine how these affect food and shelter availability for migratory songbirds. We are taking a mechanistic approach to determining how the reproductive success of populations of two songbirds species (Lapland longspur and Gambel's White-crowned sparrow) respond to variation in both shrub dominance and timing of spring snowmelt. A secondary goal is to develop techniques for monitoring songbird community characteristics via bio-acoustic recordings. For more information see project's web site: Multi-trophic impacts of climate warming in Arctic tundra
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 material is based upon work supported by the National Science Foundation, Office of Polar Programs under Grants #ARC 0908444, 0908602, and 0909133. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.