Data for: Water level drawdown makes boreal peatland vegetation more responsive to weather conditions

Climate warming and projected increase in summer droughts puts northern peatlands under pressure by subjecting them to a combination of gradual drying and extreme weather events. The combined effect of those on peatland functions is poorly known. Here, we studied the impact of long-term water level drawdown (WLD) and contrasting weather conditions on leaf phenology and biomass production of ground level vegetation in boreal peatlands. Data was collected during two contrasting growing seasons from a WLD experiment including a rich and a poor fen and an ombrotrophic bog. Results showed that WLD had a strong effect on both leaf area development and biomass production, and these responses differed between peatland types. In the poor fen and the bog, WLD increased plant growth, while in the rich fen, WLD reduced the growth of ground level vegetation. Plant groups differed in their response, as WLD reduced the growth of graminoids, while shrubs and tree seedlings benefited from it.
In additio..., The study site was located at Lakkasuo in southern Finland (61°47’N, 24°18’E). Based on its ecohydrology, Lakkasuo can be divided into a mesotrophic fen, an oligotrophic fen and an ombrotrophic bog, hereafter called rich fen, poor fen, and bog. In 2000–2001, a water level drawdown (WLD) experiment was initiated to mimic the long-term effects of lower water tables (WT) on the ecosystems. Within the three sites, an intact control area and a WLD area were established, located 20 m apart. The drainage treatment lowered the WT by an average 6.4 cm in 2017 and 7.5 cm in 2021 when compared with the control areas. To disentangle the potential effects of short-term changes in growing conditions from the long-term influence of peatland drying/drainage, we compared observations collected during two growing seasons with contrasting weather conditions, i.e., summers of 2017 (cold and wet) and 2021 (warm and dry). 
The seasonal development of leaf area index (LAI: m2 m-2) was estimated for each vascu..., ,