Potential positive effects of solar panels on peatland restoration

Peatlands have accumulated around 600 Gt of carbon throughout the Holocene, but centuries of drainage for agriculture and peat extraction have transformed these ecosystems into major carbon sources in many regions of the world. Rewetting drained peatlands can essentially reduce these emissions and is therefore a key strategy for achieving net zero targets by 2050. However, it is unclear if common rewetting measures are sufficient to restore peatlands to a near pristine state. Degraded peat soils and more frequent severe droughts under climate change often produce deeper water tables with larger seasonal fluctuations, which reduce the recovery potential of characteristic peatland vegetation such as Sphagnum mosses. Both a stable water table and, particularly in raised bogs, the re-establishment of Sphagnum are necessary to restore the carbon sink function of rewetted sites and to meet nature conservation goals. Rewetting also raises socioeconomic challenges, because rewetting land formerly used for agriculture can lead to loss of income for landowners. One recently proposed land-use approach is to combine rewetting with renewable energy production by installing solar parks on rewetted peatlands to replace the loss of income. A potential ecological benefit is reduced evapotranspiration from shading by solar panels, which could help stabilize seasonal water-table fluctuations. However, the effect of such shading on peatland vegetation, especially Sphagnum, remains unknown.  In this study, we combine process-based modeling with a field experiment to assess short- and long-term effects of solar panel shading on water table dynamics and Sphagnum growth. Preliminary results indicate that shading stabilizes water levels and, despite light limitation beneath solar panels, can enhance Sphagnum performance. These findings suggest that solar parks could simultaneously support renewable energy production and peatlands restoration.