ABSTRACT

Despite the harsh conditions, over one hundred plant species occur in Antarctica, although they are restricted to the milder areas on the Antarctic Peninsula and coastal islands. As the Antarctic continent becomes warmer and wetter due to climate change, plants are colonizing newly exposed ground, and are predicted to become more dominant. However, little is known about how warming will affect Antarctic plant communities or how increasing overall terrestrial communities of a continent, as is occurring in Antarctica via warming, will progress. Using experiments to artificially increase temperatures in plant communities in an international collaboration with biologists from Chile, this project will focus on understanding how warming will affect reproduction and chemistry of Antarctic plants. Through understanding the impacts of warming on plant biology, the project will address the critical issue of how a warming climate will impact the on-going re-vegetation of a rapidly changing continent. The project will further the NSF goal of training new generations of scientists by training multiple graduate and undergraduate students. As a central part of this research effort, the investigators will develop graduate student training and collaboration between institutions in Chile and the U.S including bringing students from Chile to be trained in new techniques in their laboratories in the U.S as well as allowing U.S. students to travel to Chile for research collaboration.

Climate change is shifting species distributions worldwide, and as temperatures continue to increase an unprecedented large-scale effect on these shifting species assemblages is predicted. Mosses are the dominant vegetation in polar regions but in contrast to Arctic systems, we know relatively little about the role of Antarctic mosses in organizing communities and less still on how warming influences Antarctic moss communities. The investigators will use Open Top Chamber passive warming experiments, which have been installed for five years by their Chilean collaborator on King George and Livingston Islands, and will concentrate on how warming impacts bryophyte productivity, sexual systems, and secondary chemistries, and on how these changes affect community processes. A suite of ecological, physiological, and molecular approaches will be used to examine how warming impacts species-specific moss function, community assembly, and ultimately, the moss-mediated engineering of the Antarctic ecosystem. The team will test three integrated research hypotheses: 1) Warming will alter moss species composition, moss sex ratio, and differentially impact moss productivity and reproductive success in Antarctica; 2) Warming will impact the production of moss secondary compounds, influencing the dynamics of biotic interactions and biosphere-atmosphere exchange in terrestrial Antarctica; and 3) Warming will alter moss-microbe interactions, resulting in alterations to the moss food web and community dynamics in terrestrial Antarctica. These data will be the first comprehensive measures of how Antarctic mosses engineer their environment and thereby drive terrestrial responses to warming.

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