Steven Mamet

Steven Mamet

Biography

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.

Microbial ecology
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.

Biographie

Steven Mamet est originaire d’Edmonton, en Alberta, au Canada, près de la limite sud de la forêt boréale. Ses recherches ont porté sur les limites de l’aire de répartition géographique des arbres, ainsi que sur les changements environnementaux dans les zones de pergélisol continu et discontinu. Il s’intéresse largement aux communautés végétales, se concentrant sur la démographie et la croissance le long des gradients environnementaux.

Écologie microbienne
Les recherches postdoctorales actuelles de Steve portent sur les interactions microbiennes le long des gradients d’invasion des plantes et dans les zones perturbées par des facteurs naturels ou anthropiques. À l’aide de données provenant de nouveaux essais de diversité végétale et de séquençage d’ADN à haut débit, il suit les communautés microbiennes actives sur le plan écologique et détermine qui interagit avec qui, dans les prairies et les sites contaminés par les hydrocarbures. Les résultats de cette étude et d’autres recherches suggèrent que la compréhension des processus et des interactions souterrains est primordiale pour élucider les processus mécanistes sous-jacents aux modèles de végétation en surface.

Dynamique du pergélisol et de la végétation
Steve est co-chercheur principal de l’expédition Climate Change at the Arctic Edgewatch depuis 2013. Son objectif est de s’appuyer sur des études passées et simultanées sur la végétation et le pergélisol à la limite des arbres afin de fournir des conditions de base auxquelles il peut comparer les changements climatiques récents et rapides à la dynamique du pergélisol. Plus précisément, il s’est engagé à prolonger les observations sur le terrain à long terme des régimes thermiques actuels de pergélisol / couche active et de couche limite à Churchill, au Manitoba (2000-présent) et Macmillan Pass, Territoires du Nord-Ouest (1990-présent). Ces enregistrements sont essentiels pour la détection du signal climatique terrestre dans le pergélisol et sa variabilité spatio-temporelle. Les résultats de ses recherches amélioreront considérablement notre compréhension des facteurs qui déterminent le profil et le processus des arbres des informations essentielles pour développer des modèles couplés physico-écologiques afin de prévoir les réponses futures de l’écotone de la limite des arbres aux changements environnementaux.

Selected Publications/ Publications sélectionnées

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.