Warming winters


In temperate ecosystems, winter is the season of resource scarcity and energy deficits. To escape the harsh winter environment, many organisms persist within a stable and seasonal environment underneath the snowpack, the subnivium. The climate of the subnivium is dependent on bioclimatic features like snow duration, density and depth, and is a major factor in the overwintering success of plants and animals. Within the Great Lakes Region, the subnivium is historically important, yet winter conditions are changing rapidly. By 2050, mean winter temperatures are predicted to be 3-4 C warmer and the period of snowcover 4 weeks shorter. These climatic changes will likely result in important changes in the subnivium, from fine-scale variability in subnivium temperatures to broad-scale changes in distributions of species dependent on this environment.

We are collaborating with Dr. Jonathan Pauli to better understand how climate change will affect the conditions and distribution of this sensitive seasonal refugium. Over the course of two winters, we collected data on the biophysical conditions responsible for the formation of the subnivium to predict its future extent and duration in the context of forecasted changes in winter climate. Our approach centered on the deployment of automated micro-greenhouses, in which conditions were controlled to mimic those predicted by 2050, across major land cover and latitudinal gradients within the Great Lakes Region. The placement of micro-greenhouses is guided by a robust macroecological design meant to capture the full range of expected climate change and patterns of snow fall and cover across the Great Lakes Region. This project has provided new information on the establishment, maintenance, and temperature dynamics of the subnivium, as well as the extent to which climate change will affect these attributes. Funding is provided for by NSF Macrosystems.

Conservation of Winter Biodiversity in a Warming World

Maintenance of extant biodiversity is paramount since it is recognized that biodiversity stabilizes ecosystems, promotes human well-being, and contributes to elevated ecosystem function. However, global climate change poses a unique subset of challenges and potential threats for the preservation of global biodiversity. Temperate systems characterized by seasonal snow cover are undergoing rapid changes facilitated by climate change as snowpack extent, quality, and duration are all reduced by a warming climate. Furthermore, the transitional zone of the cryosphere, where rain-dominated systems give way to snow-dominated systems, is expected to move northward and higher in elevation. Shifts and reduction in the availability of snow cover poses large challenges for cold-adapted species that rely heavily on snow as climatic refugia. Changes in the spatiotemporal distribution of snow cover will likely impose changes to cold-adapted species assemblages through mechanisms such as reduction in species’ physiological tolerance to ambient conditions leading to ecological patterns such as novel winter communities and reductions in ecosystem stability.

As part of a project funded by NASA and as a collaborative effort between Dr. Jonathan Pauli, Dr. Volker Radeloff, Dr. Daniel Fink, and Dr. Shawn Carter we aim to 1) characterize shifts in snow cover dynamics at a high spatiotemporal resolution and deliver high-quality remote sensing products, 2) identify areas of high winter biodiversity (i.e. cold-adapted birds and mammals) and examine long-term shifts in winter biodiversity, 3) assess the current network of protected areas across the United States in terms of winter environments and areas of high winter biodiversity, and 4)  work with a variety of protected area managers to integrate products and information generated during this project to provide insight for best land management practices in important areas for winter biodiversity. This project works to promote various aspects of the United Nations Sustainable Development Goals (i.e. SDG 15: “Life on Land”), posing ample opportunity for scientific advancement and direct conservation/sustainability applications.

Recent related publications

Thompson, K.L.B. Zuckerberg, W.P. Porter, and J.N. Pauli. 2018. The phenology of the subnivium. Environmental Research Letters 13: 064037

Petty, S.K.,B. Zuckerberg and J.N. Pauli. 2015. Winter conditions and land cover structure the subnivium, a seasonal refuge beneath the snow. PLOS ONE 10: e0127613. Link

Pauli, J.N., B. Zuckerberg, J. P. Whiteman, and W. Porter. 2013. The subnivium: a decaying seasonal refugium. Frontiers in Ecology and the Environment 11:260-267. Link