Counting marmots…
Non-technical Abstract (Project 1): Climate change is predicted to decrease biodiversity by increasing the extinction risk of many species, but there are very few examples of climate change actually leading to population declines, because this is a challenging topic to study. One prominent way that climate change is expected to affect populations is by changes in the timing of life-cycle events, such as flowering date or date of emergence from hibernation. Despite changes in the timing of such events being one of the most widespread biological responses to climate change, incredibly little is known about whether and how changes in timing affect popualtions, especially for plants. This project therefore aims to link climate change-induced shifts in the timing of life-cycle events, such as leaf-out and flowering, to plant population dynamics. We are conducting a field experiment where we experimentally advance the timing of leaf-out and flowering in several plant species by melting the snow early. These plants will be compared to control plants to learn how these earlier life-cycle events affect plant survival and reproduction. The data from the field study will be used to build population models that will allow us to understand whether earlier life-cycle events increase or decrease plant popualtions, and why (or have no effect). In doing so, this project will be one of the most comprehensive assessments to date of the risk that climate change-induced earlier life-cycle events pose to plant biodiversity. Non-technical Abstract (Project 2): Pollinator populations are declining, but we have a very poor understanding of the ecological consequences of these declines. There is widespread concern that many flowering plant species will decline in tandem with pollinators because approximately 87% of flowering plants rely on animal pollination for their reproduction. Increases in pollination typically increase the number of seeds a plant can make, and because of this, scientists who study pollination often assume that changes in the amount of pollination have direct consequences for the persistence of plant populations. However, the number of seeds a plant makes typically does not limit population growth, especially for perennial plants. This suggests that alterations to pollination may not actually have extensive consequences for plant populations. But no studies have connected pollinator-mediated declines in seed output to the actual ability of a plant population to persist. This project makes that connection using mathematical population models informed by data from a field experiment. In doing so, this project will advance basic scientific knowledge by bridging two ecological subfields that are surprisingly disconnected, and it will increase our understanding of the ecological consequences of pollinator declines.