I combine ecological modeling approaches with extensive field work to understand what drives species geographic distributions and how these will shift with global change.
[PUBLICATION LIST] [OPEN ACCESS DATA]
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PREDICTIONS OF POPULATION PROCESSES
Recent quantitative advances have greatly improved ecological models, yet detailed scrutiny is critical to evaluate their accuracy and predictive power. For example, outputs of commonly used Integral Projection Models (IPMs) quickly converge with those of classic Matrix Models, illustrating that IPMs fail to provide more accurate estimations of demographic rates. Another challenge is that ecological spatial models lack geographical precision and cannot predict relevant population processes. In my current postdoctoral work with Signe Normand and Sonja Wipf, I am testing if highly precise spatial models can predict population-level processes, such as shrub growth and abundance in Greenland. I collaborated with the Greenland Institute of Natural Resources (Inuit lands) in Summer 2020 to collect independent validation data, a rare yet promising approach.
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RANGE SHIFT FORECASTS
Simple climate-based range shifts predictions are often inaccurate due to a lack of understanding of how separate populations within a species range respond to climate. In my undergraduate research with David Ackerly and Will Cornwell, I showed that geographic range limits are not at the edge of the climate envelope, illustrating that northern range limits do not necessarily correspond to a species' colder range edge. During my PhD and in collaboration with Sam Pironon, Megan Peterson, and Daniel Doak, I illustrated that incorporating local adaptation to climate substantially increases SDM accuracy. However, these improved SDMs cannot predict ecological function, suggesting that SDM-based forecasts do not capture broader ecological impacts. |
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HUMAN DISTURBANCE IMPACTS
While disturbances have the potential to alter competitive interactions that influence range limits, anthropogenic disturbances are often left out of range limit research. In a multi-year international field campaign during my PhD, I found that human trampling disturbance has differential impacts on range limits, highlighting the need to include disturbances in species distribution predictions as well as in landscape management. Working with Sonja Wipf and Christian Rixen during my doctoral fellowship, I furthermore showed that disturbance reduces reproduction and decreases overall species diversity in a community that is surprisingly dominated by competitive, not facilitative, interactions. |
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Funding for this work generously provided by: Swiss Polar Institute; Zeno Karl Schindler Foundation; American Alpine Club; Environmental Studies Program at University of Colorado, Boulder; Indian Peaks Wilderness Alliance; John Marr Ecology Fund; Hazel Schmoll Research Fellowship; Botanical Society of Switzerland.
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