Two large scale climate refugia projects now established in Sweden

This summer, members from our Lab (Jonathon Winnel, Stuart Fell and Sofia Corsetti) undertook a large field campaign across Sweden to establish two new projects investigating climate refugia and range dynamics of two boreal understory species: Calypso bulbosa and Nephroma arcticum. The aim of these projects is to help fill critical knowledge gaps required for the effective implementation of climate refugia as an important climate adaption tool!

Stuart Fell records individual plant characteristics at a Calypso bulbosa population in northern Sweden

Climate refugia are relatively cool places in the forest landscape that are buffered from climate change. These are often locations where topography and vegetation features combine to buffer the microclimate, such as densely forested pole-facing slopes and river gorges. Identifying and protecting climate refugia is a potentially important climate adaptation tool because climate refugia can:

• Allow species to persist under climate change

• Allow time for adaptation to occur

• Act as stepping stones through the landscape

• Increase local genetic and species diversity

• Buy time to allow scientists to come up with more solutions to conserve biodiversity and ecosystem functioning

• Act as source populations for species to redisperse from should suitable climate conditions return

However a number of important knowledge gaps currently prevent effective implementation of this potentially important climate adaptation tool that we hope to answer with these two projects. We need to know more about the of role of interaction with the surrounding community and we also need to understand more about the relative importance of different microclimate gradients.

Sofia Corsetti records canopy cover by taking a hemispherical photo at a Nephroma arcticum population in far northern Sweden

Project Calypso bulbosa: The aim of this project is to understand how microclimate preferences of this red listed orchid species vary across its range in Sweden and what effect competition with the surrounding vegetation has on an individual and a population. To investigate this we installed TMS-4 loggers at 35 populations of C. bulbosa, from the southernmost known limit to the northernmost known limit of C. bulbosa in Sweden. At a number of sites we established long term plots where we manipulated vegetation cover to investigate the role of competition on C. bulbosa performance across its range.

Calypso bulbosa (Nornna) is a rare orchid in Sweden

Project Nephroma arcticum: The aim of this project is to investigate microclimate preferences and the effect of gastropod herbivory across the range of this boreal lichen. To do this we established a large-scale transplant experiment across most of Sweden. At 46 known sites of N. arcticum we placed 6 transplants of N. arcticum and in half of the transplants we excluded gastropods. To describe the microclimate at each site we installed TMS-4 loggers. We will follow the growth of the transplants over multiple years and compare how growth relates to differences in microclimate and gastropod herbivory across the entire Swedish range. In addition we are also investigating N. arcticum’s symbiont community to see how it varies in relation to space, microclimate and the soil microbial community.

Transplants of Nephroma arcticum (norrlandslarv) are coupled with a TOMST microclimate logger that records the temperature and soil moisture every 15 minutes

These projects will provide important insights into our understanding of climate refugia, namely, the relative importance of different microclimate gradients and the role that competition and herbivory have in defining climate refugia!