@article {4488, title = {Genetic diversity of soil invertebrates corroborates timing estimates for past collapses of the West Antarctic Ice Sheet}, journal = {Proceedings of the National Academy of Sciences}, year = {2020}, month = {08/2020}, abstract = {

During austral summer field seasons between 1999 and 2018, we sampled at 91 locations throughout southern Victoria Land and along the Transantarctic Mountains for six species of endemic microarthropods (Collembola), covering a latitudinal range from 76.0\°S to 87.3\°S. We assembled individual mitochondrial cyto-chrome c oxidase subunit 1 (COI) sequences (n = 866) and found high levels of sequence divergence at both small (\<10 km) and large (\>600 km) spatial scales for four of the six Collembola species. We applied molecular clock estimates and assessed genetic divergences relative to the timing of past glacial cycles, including collapses of the West Antarctic Ice Sheet (WAIS). We found that genetically distinct lineages within three species have likely been isolated for at least 5.54 My to 3.52 My, while the other three species diverged more recently (\<2 My). We suggest that Collembola had greater dispersal opportunities under past warmer climates, via flotation along coastal margins. Similarly increased opportunities for dispersal may occur under contemporary climate warming scenarios, which could influence the genetic structure of extant populations. As Collembola are a living record of past landscape evolution within Antarctica, these findings provide biological evidence to support geological and glaciological estimates of historical WAIS dynamics over the last ca. 5 My.

}, keywords = {LTER-MCM, climate change, microarthropods, molecular clock, phylogeography, terrestrial biodiversity}, doi = {10.1073/pnas.2007925117}, url = {https://www.pnas.org/content/early/2020/08/19/2007925117}, author = {Gemma E. Collins and Hogg, Ian D. and Convey, Peter and Sancho, Leopoldo G. and Cowan, Don A. and W. Berry Lyons and Byron Adams and Diana H. Wall and Allan Green, T. G.} } @article {4153, title = {Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem}, journal = {Communications Biology}, volume = {2}, year = {2019}, month = {02/2019}, abstract = {

Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km2. Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.

}, keywords = {LTER-MCM}, doi = {10.1038/s42003-018-0274-5}, url = {https://www.nature.com/articles/s42003-018-0274-5}, author = {Charles K. Lee and Laughlin, Daniel C. and Bottos, Eric M. and Caruso, Tancredi and Joy, Kurt and John E. Barrett and Brabyn, Lars and Uffe N. Nielsen and Byron Adams and Diana H. Wall and D. W. Hopkins and Pointing, Steve B. and McDonald, Ian R. and Cowan, Don A. and Banks, Jonathan C. and Stichbury, Glen A. and Jones, Irfon and Zawar-Reza, Peyman and Katurji, Marwan and Hogg, Ian D. and Sparrow, Ashley D. and Storey, Bryan C. and Allan Green, T. G. and Craig S Cary} } @article {4014, title = {Genetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone 1}, journal = {Genome}, volume = {59}, year = {2016}, month = {Jan-09-2016}, pages = {762 - 770}, keywords = {LTER-MCM}, issn = {0831-2796}, doi = {10.1139/gen-2015-0194}, url = {http://www.nrcresearchpress.com/doi/10.1139/gen-2015-0194}, author = {Clare R. Beet and Hogg, Ian D. and Gemma E. Collins and Cowan, Don A. and Diana H. Wall and Byron Adams and John-James Wilson} } @inbook {3221, title = {Antarctic Terrestrial Microbiology : Invertebrates}, year = {2014}, pages = {55 - 78}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, abstract = {

Terrestrial invertebrates are the largest permanent residents for much of the Antarctic continent with body lengths \< 2 mm for most. The fauna consists of the arthropod taxa Collembola (springtails) and Acari (mites) as well as the microinvertebrates Nematoda, Tardigrada and Rotifera. Diversity in continental Antarctica is lower compared with warmer regions such as the Antarctic Peninsula and the subantarctic islands and several taxa such as the arthropods have considerably restricted distributions. The highest diversity of invertebrates is found along the Transantarctic Mountains of the Ross Sea Region and taxa are likely to be relicts from a warmer past that have survived in glacial refugia. Dispersal among the extremely fragmented Antarctic landscape is likely to be limited to transport via fresh- or salt-waters, particularly for the arthropod taxa, although long-distance wind dispersal is also possible for the microinvertebrates. Invertebrates possess several adaptations to low moisture levels and extreme cold temperatures in Antarctica. For example, nematodes and tardigrades avoid extreme dry and cold temperatures by entering a desiccation-resistant anhydrobiotic state. In contrast, arthropods do not have such a resistant state and freezing is lethal. Adaptations for the arthropod taxa include freeze avoidance and the production of intracellular, antifreeze proteins. Climate changes in Antarctica are likely to pose significant challenges for the invertebrate fauna. Changes in temperature, soil moisture and associated shifts in taxon distributions as well as the potential for non-indigenous species introductions are all likely to have considerable impacts on the Antarctic fauna. From a conservation perspective, there is a pressing need for terrestrial observation networks to record the present state of Antarctic terrestrial ecosystems as well as to monitor impending changes. Biosecurity measures which minimize species introductions or transfers of organisms within Antarctica will be essential.

}, keywords = {LTER-MCM}, isbn = {978-3-642-45212-3}, doi = {10.1007/978-3-642-45213-0_4}, url = {http://link.springer.com/content/pdf/10.1007/978-3-642-45213-0_4}, author = {Hogg, Ian D. and Stevens, Mark I. and Diana H. Wall}, editor = {Cowan, Don A.} } @article {3535, title = {Challenges to the Future Conservation of the Antarctic}, journal = {Science}, volume = {337}, year = {2012}, month = {Jan-07-2013}, pages = {158 - 159}, abstract = {

The Antarctic Treaty System, acknowledged as a successful model of cooperative regulation of one of the globe\&$\#$39;s largest commons (1), is under substantial pressure. Concerns have been raised about increased stress on Antarctic systems from global environmental change and growing interest in the region\&$\#$39;s resources (2,\ 3). Although policy-makers may recognize these challenges, failure to respond in a timely way can have substantial negative consequences. We provide a horizon scan, a systematic means for identifying emerging trends and assisting decision-makers in identifying policies that address future challenges (2,\ 3). Previous analyses of conservation threats in the Antarctic have been restricted to matters for which available evidence is compelling (4). We reconsider these concerns because they might escalate quickly, judging from recent rapid environmental change in parts of Antarctica and increasing human interest in the region (see the map). We then focus on a more distant time horizon.

}, keywords = {LTER-MCM}, issn = {0036-8075}, doi = {10.1126/science.1222821}, url = {http://www.sciencemag.org/cgi/doi/10.1126/science.1222821}, author = {Steven L. Chown and Lee, J. E. and Hughes, K. A. and Barnes, J. and Barrett, P.J. and D.M. Bergstrom and Convey, P. and Cowan, Don A. and Crosbie, K. and Dyer, G. and Frenot, Y. and Grant, S. M. and Herr, D. and Kennicutt, M. C. and Lamers, M. and Murray, A. and Possingham, H. P. and Reid, K. and Riddle, M. J. and Ryan, P. G. and Sanson, L. and Shaw, J. D. and Sparrow, M.D. and Summerhayes, C. and Terauds, A. and Diana H. Wall} }