Our research group works at the interface between global change biology, macroecology, biogeography, community, ecosystem ecology and remote sensing. Much of our research focuses on understanding the biological and climatic drivers that promote shrub expansion and the ecosystem consequences of this vegetation change for ecosystem functioning and the conservation of tundra ecosystems.
In the Arctic, our research demonstrates a dramatic transformation of plant communities. We have found that vegetation is increasing and bare ground is decreasing (Elmendorf… Myers-Smith et al. Nature Climate Change 2012), and where plants once grew they are now growing taller (Bjorkman, Myers-Smith et al. Nature 2018). Tundra shrub cover is increasing (García Criado, Myers-Smith et al. Global Ecology and Biogeography, 2020), shrublines are advancing (Myers-Smith and Hik, J Ecology, 2018) and shrub growth is climate sensitive (Myers-Smith et al. Nature Climate Change 2015). Yet, biotic interactions may also influence rates of vegetation change (Angers-Blondin, Myers-Smith, Boudreau Polar Biology 2018).
In recent studies, we find that plants are greening up earlier in spring (Assmann, Myers-Smith, et al. Global Change Biology 2019), with climate sensitivity flowering (Prévey… Myers-Smith, et al. GCB 2018), but growing seasons are not necessarily becoming longer (Myers-Smith et al. Ecological Monographs 2019; Prévey… Myers-Smith, et al. Nature Ecology & Evolution 2019). Our remote sensing research indicates that Arctic greening signals detected by satellites represent a more complex land-surface response than vegetation change alone (Myers-Smith et al. Nature Climate Change 2020). Drones allow for cross-scale analyses to bridge the scale gaps between satellite observations and ecological monitoring (Cunliffe, Myers-Smith et al. Environmental Research Letters 2020; Assmann, Myers-Smith et al. ERL 2020).
Globally, our research demonstrates that a broad spectrum of population and biodiversity change is occurring across the planet (Blowes… Myers-Smith et al. Science 2019; Daskalova, Myers-Smith et al. Science 2020; Daskalova, Myers-Smith et al. Nature Comms 2020). Land-use change such as forest cover loss is catalysing biodiversity change including both increases and decreases in the abundance of species and accelerated change in the composition of ecological assemblages (Daskalova, Myers-Smith et al. Science 2020). Taken together, our research is showing that it is the traits and assemblages of species (Thomas, Myers-Smith et al. Nature Comms 2020; Bjorkman, Myers-Smith et al. Nature 2018) and not simply their biodiversity (Vellend… Myers-Smith, et al. PNAS 2013) that is influencing the functioning of ecosystems as global change intensifies.
1. How is tundra vegetation changing in response to global change?
There is growing evidence for increasing shrubs in many tundra ecosystems. Increased shrubs could be due to a warming climate and improved growing conditions or a variety of other factors. We use historical data sets such as repeat photography to explore vegetation change in tundra ecosystems. We are interested in research questions such as whether shrub species have the potential to form dominant canopies at the northern range edge or whether growth forms are locally adapted.
2. Does on-the-ground vegetation change correspond with satellite observations of tundra greening?
Satellites are observing a greening of tundra ecosystems concurrent with the recent Arctic warming trend. Does this greening correspond with on-the-ground observations of vegetation change? We work with circumArctic datasets and collaborators at sites around the Arctic (HiLDEN, ShrubHub, sTUNDRA, ITEX), remotely sensed satellite data and drones (remotely piloted aircraft systems or UAVs) through the High Latitude Drone Ecology Network to ask this scaling question at our focal research sites and across the tundra biome as a whole.
3. How will vegetation change modify the tundra ecosystem function?
We investigate the feedbacks among vegetation change, ecosystem functions and climate. Shrubs can influence the reflectivity (albedo) of tundra ecosystems which could feedback to influence climate warming. In winter, shrubs can trap snow. In summer, shrubs can shade soils. Changes in plant litter inputs can influence the rates of decomposition of tundra soils. These processes could feedback to influence nutrient cycling, carbon stores and biodiversity. We work with trait databases (TRY), field experiments (Tundra Tea Bag Experiment) and hierarchical models to test the relationships between vegetation change, warming, trait change and ecosystem functions.
Much of our field research takes place in the Yukon Territory of Northern Canada. In the Kluane Region of the Southwest Yukon, we are exploring changes in the shrubline ecotone. At the Qiqiktaruk – Herschel Island site on the Arctic Coast of the Yukon Territory, we are exploring vegetation-permafrost interactions.
Much of our research is field-based experimental or observational ecology. We conduct collaborative research, use large scale data sets and statistical modelling to explore patterns of change at the tundra biome scale. We use dendroecology to work back in time and understand how shrub growth has changed over the previous decades and to estimate the climate sensitivity of shrub growth. We have established a common garden experiment in 2013 to test for local adaptation in growth form in tundra willows across climate and latitudinal gradients. And since 2015, we have been working with drones (remotely piloted aircraft systems or UAVs) to link on-the-ground measurements and satellite observations of tundra vegetation change.