Collaborative research: Understanding the role of environmental change on the long-term population dynamics of one surviving and two extinct arctic mammals

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Of the planet?s ecosystems the Arctic is the most sensitive to climate change. Recent increases in the rate of environmental change in the Arctic pose considerable challenges to the survival of culturally and economically important, arctic-adapted species such as caribou. An ability to disentangle the roles of extrinsic processes, such as climatic or anthropogenic changes to the arctic habitat, and intrinsic processes, such as density-dependent resource limitation, in the dynamics of populations would provide key insights for conservation and management of the arctic biota. However, such efforts have thus far been hindered by the scarcity of long-term data for natural populations. Here, contemporary evolutionary and ecological approaches are integrated for the first time to produce long-term reconstructions of the population dynamics of one surviving and two extinct and arctic mammals: steppe bison, horses, and caribou. To achieve this, the largest, most densely sampled ancient DNA data sets to date will be produced, focusing on two environmentally distinct arctic localities with exceptional chronological control and detailed paleoenvironmental records going back at least 250,000 years. These data will provide the first opportunity to directly evaluate the role of environmental change on the long-term dynamics and extinction risk of arctic fauna. A near-continuous time series detailing changes in the size and structure of bison, horse and caribou populations will be generated, spanning one complete glacial/interglacial cycle and several periods of major environmental change. Novel analytical techniques will be developed to (a) significantly extend the temporal range of paleogenetic reconstructions; (b) incorporate geographic and ecological data explicitly into demographic analyses; and (c) detect and quantify the role of intrinsic and extrinsic processes in the fate of natural populations of large herbivores. In addition, a detailed analysis of evolutionary information in mitochondrial DNA sequences will be performed, using high-throughput sequencing technology and novel experimental methodology to develop the first comparative temporal data set of complete mitochondrial genomes for sympatric (spatially and temporally) species. In addition, understanding how species respond to previous periods of climate change may improve our ability to forecast and mitigate adverse consequences of contemporary climate change for extant arctic species.