Steven Mamet is originally from Edmonton, Alberta, Canada, near the southern limit of the boreal forest. His research background has focused on geographic range limits of trees, as well as environmental change in continuous and discontinuous permafrost zones. He is broadly interested in vegetation communities, focusing on demographics and growth along environmental gradients.
Steve’s current postdoctoral research focuses on microbial interactions along plant invasion gradients and in naturally- and anthropogenically-disturbed areas. Using data from novel plant diversity assays and high-throughput DNA sequencing, he tracks active ecologically active microbial communities and determines who interacts with who in polar desert frost boils, grasslands, and hydrocarbon contaminated sites. Results of this, and other research suggest understanding belowground processes and interactions is paramount to elucidating mechanistic processes underlying aboveground vegetation patterns.
Permafrost and vegetation dynamics
Steve has been co-principle investigator of the Climate Change at the Arctic’s Edge Earthwatch Expedition since 2013. His aim is to build on past and concurrent studies of vegetation and permafrost at treeline in order to provide baseline conditions to which he can compare recent, rapid climatic changes to permafrost dynamics. Specifically, he is committed to extending existing long-term field observations of present permafrost/active layer and boundary layer thermal regimes at Churchill, Manitoba (2000-present), and Macmillan Pass, Northwest Territories (1990-present). These records are essential for the detection of the terrestrial climate signal in permafrost and its spatiotemporal variability. Results of his research will significantly improve our understanding of factors that determine treeline pattern and process; information that is essential for developing coupled physical-ecological models to predict future responses of the treeline ecotone to environmental change.
MULLER, A., HARDY, S., MAMET, S.D., OTA, M., LAMB, E., & SICILIANO, S.D. (2017) Salix arctica changes root distribution and nutrient uptake in response to subsurface nutrient patches in high arctic deserts. Ecology 98(8): 2158–2169. doi:10.1002/ecy.1908. To assist with the amalgamation of data sets from two graduate students, Mamet contributed to data analysis, writing of the manuscript, and developed two of three figures.
MAMET, S.D., CHUN, K.P., KERSHAW, G.G.L., LORANTY, M.M., & KERSHAW, G.P. (2017) Recent increases in permafrost thaw rates and areal loss of palsas in the western Northwest Territories, Canada. Permafrost and Periglacial Processes. Early View – doi:10.1002/ppp.1951.
CHUN, K.P., MAMET, S.D., METSARANTA, J. BARR, A., JOHNSTONE, J.F., & WHEATER, H. (2017) A novel stochastic method for reconstructing daily precipitation times-series using tree-ring data from the western Canadian boreal forest. Dendrochronologia 4: 9–18. Mamet provided the tree ring data and chronology analysis, wrote the sections on boreal forest ecology, and contributed to manuscript conceptualization and figure design.
MAMET, S.D., LAMB, E.G., PIPER, C.L., WINSLEY, T., & SICILIANO, S.D. (2017) Archaea and bacteria mediate the effects of native species root loss on fungi during plant invasion. The ISME Journal. doi:10.1038/ismej.2016.205.
MAMET, S.D., YOUNG, N., CHUN, K.P., & JOHNSTONE, J.F. (2016) What is the most efficient and effective method for long-term monitoring of alpine tundra vegetation? Arctic Science 2(3): 127–141.
MAMET, S.D., CHUN, K.P., METSARANTA, J.F., BARR, A., & JOHNSTONE, J. (2015a) Tree rings provide early warning signals of jack pine mortality across a moisture gradient in the southern boreal forest. Environmental Research Letters 10(8): 084021.
MAMET, S.D., CAIRNS, D.M., BROOK, R.K., & KERSHAW, G.P. (2015b) Modeling the spatial distribution of subarctic forest in northern Manitoba using GIS-based terrain & climate data. Physical Geography 36(2): 93–112.
IRESON, A.M., BARR, A.G., JOHNSTONE, J.F., MAMET, S.D., VAN DER KAMP, G., WHITFIELD, C., MICHEL, N.L., NORTH, R., WESTBROOK, C., DEBEER, C., CHUN, K.P., NAZEMI, A. & SAGIN, J. (2015) The Changing Water Cycle: The Boreal Plains Ecozone of Western Canada. WIREs Water 2(5): 505–521. Mamet led the writing on vegetation response to climate change, and contributed to manuscript conceptualization and figure design.
MAMET, S.D. & KERSHAW, G.P. (2013a) Multi-scale analysis of environmental conditions & conifer seedling distribution across the forest-tundra ecotone of northern Manitoba, Canada. Ecosystems 16(2): 295–309.
MAMET, S.D. & KERSHAW, G.P. (2013b) Age-dependency, climate & environmental controls of recent tree growth trends at subarctic & alpine treelines. Dendrochronologia 31(2): 75–87.
MAMET, S.D. & KERSHAW, G.P. (2013c) Environmental influences on winter desiccation of Picea glauca foliage at treeline, & implications for treeline dynamics in northern Manitoba. Arctic, Antarctic, and Alpine Research 45(2): 219–228.
MAMET, S.D. & KERSHAW, G.P. (2012) Subarctic & alpine treeline dynamics during the last 400 yrs in northwestern & central Canada. Journal of Biogeography 39(5): 855–868.
MAMET, S.D. & KERSHAW, G.P. (2011) Radial-growth response of forest-tundra trees to climate in the western Hudson Bay Lowlands. Arctic 64(4): 446–458.