Evaluating the thermal effects of peatland restoration using UAV monitoring

Mid-latitude montane peatlands have undergone extensive anthropogenic modifications in past decades. Projects aimed at their restoration represent critical ecological interventions, reinstating their hydrological regime, preserving biodiversity, and mitigating the effects of climate change.

This research aims to investigate the effect of mid-latitude montane peatland restoration on the responses in land surface temperature (LST) and wetness using multispectral and thermal UAVs supported by instrumental monitoring. We aimed to test the hypothesis that peatland restoration should have a cooling effect on LST due to increased wetness, enhanced evapotranspiration, and latent heat flux.

Multispectral and thermal UAV monitoring, coupled with in-situ instrumental monitoring, was used to acquire data on spatial, quantitative, and qualitative changes in peatland response to restoration aimed at plugging the drains built in the past decades. In particular, we investigated: (i) the change in total surface water extent after peatland restoration, (ii) the LST response of restoration dikes, and (iii) the distribution of LST in restored peatlands.

The study was conducted in the montane peat bog of Rokytka in the Šumava Mountains, one of Central Europe's largest montane peatland complexes. The monitoring covered the vegetation seasons from 2018 to 2023, a period of extensive restoration activities in the peatland headwaters, allowing assessment of both pre-and post-restoration conditions.

The very high spatial resolution of the spatial data allowed us to analyze changes in peatland area in terms of canopy structure, wetness, and thermal response. The results showed a significant expansion of the waterlogged surface of the peatland due to the clogging of the former drains. However, the land surface temperature analysis indicates that the newly constructed dike systems have only a limited cooling effect compared to the thermal regime of the natural peatland vegetation. Furthermore, the analysis of new and old dike systems showed a continuous decrease of their positive effect.

The study proved that UAV monitoring is a unique monitoring technique that allows obtaining objective information on the thermal effects of peatland restoration, separating their effects from the properties of the surrounding environment, and objectively assessing their impact on the peatland thermal regime.