Meteorological Controls on Water Table Dynamics in Fen Peatlands Depend on Management Regimes

Abstract

Fens belong to the most threatened ecosystems in Europe. Maintaining a high water table through rewetting is an effective measure to rehabilitate many of their ecosystem functions. However, the impact of meteorological conditions such as vapor pressure deficit (VPD) and precipitation on water tables is still unclear for rewetted fens. Here, we compare the impact of meteorological factors on water table dynamics in a drained and a rewetted fen, using multiple regression with data from continuous high-resolution (temporal) water level monitoring and weather stations. We find that an increase in the daily mean VPD causes a higher drop in the water table at the drained and degraded fen compared to the rewetted fen. Precipitation contributes to recharge, causing the water table to rise higher at the drained site than at the rewetted site. We attribute the differential influence of meteorological conditions on water table dynamics to different soil specific yield values (i.e., water storage capacity) largely driven by lower water table position at the drained site. Our study underlines the importance of understanding how and why water tables in peatlands vary in response to meteorological factors for management decisions (e.g., rewetting). Continuous monitoring of water table and vegetation development in rewetted fen peatlands is advisable to ensure long-term success especially under climate change conditions and associated drought events.

Natural Climate Protection through Peatland Rewetting: A Future for the Rathsbruch Peatland in Germany

“…Biodiversity loss is a critical threat, and preserving natural habitats, expanding protected areas, and restoring the degraded landscapes are crucial steps in biodiversity improvement. If the authors' findings [2] are followed, it becomes evident that the current consumption of land and resources by humans, alongside the corresponding environmental changes, has a predominantly negative impact on biodiversity at all levels, ranging from genetic diversity Land 2024, 13, 581 2 of 29 to the biome. Reintroducing degraded lands into new green infrastructures for urban areas [3,4], or areas close to the natural state habitats, is supported by ecological engineering approaches to reduce the land consumption pressures of built-up environments.…”

“…However, intact peatlands mitigate the effects of global warming by manipulating the water cycle in two ways. According to Ahmad, Liu, and Alam et al [13], there is a connection between the meteorological influences, the groundwater level, and the latent heat flow. This comparison between a drained and a rewetted moor (same area) showed that on the one hand, the groundwater fluctuations were less pronounced; therefore, the daily evaporation for the rewetted moor could be increased by around 2.5 times.…”

Influence of vegetation‐induced water table seasonality on groundwater chloride concentration dynamics in a riparian fen peatland

“…The depth to water table in peatlands is not homogeneous and depends on spatial location (Joris & Feyen, 2003), soil physical parameters (Ahmad et al, 2021), vegetation cover (Volik et al, 2020), and of course seasonal atmospheric forcings. As a consequence, its effect on the concentrations of chemical elements varies both spatially and temporally.…”

“…Although chloride behaviour is affected by several processes that indicate topsoil transformation, the depth to water table remains a crucial factor for the chloride concentrations in shallow groundwater. The depth to water table in peatlands is not homogeneous and depends on spatial location (Joris & Feyen, 2003), soil physical parameters (Ahmad et al, 2021), vegetation cover (Volik et al, 2020), and of course seasonal atmospheric forcings. As a consequence, its effect on the concentrations of chemical elements varies both spatially and temporally.…”

Near‐surface controls on peatland hydrology: Implications for rapid adaptation and enhanced resilience to disturbances

“…Despite the importance of these near‐surface controls on peatland hydrology and carbon sequestration, historically the quantification of peatland hydrophysical properties and the hydrological simulation of the ecosystems has focused on peat properties at depth (Wang et al, 2021), linking surface ecological dynamics with the water table depth (WTD) (Ahmad et al, 2021). However, more recently, notably Canadian, peatland studies evaluated moss moistures stresses via known ecohydrological thresholds by quantifying bulk densities, hydrophysical properties, water table depths and peat moistures of very near‐surface layers regrowing or recolonizing onto the cutover surface (Cagampan & Waddington, 2008; Gauthier et al, 2018; Golubev et al, 2021; McCarter & Price, 2015; Turetsky et al, 2008; Waddington et al, 2011) This focus on near‐surface properties and hydrological dynamics is important.…”