Two mechanisms drive changes in boreal peatland photosynthesis following long-term water level drawdown: species turnover and altered photosynthetic capacity

Datasets that support the major results of the study that quantifies the long-term consequences of climate change-induced drying for peatland photosynthesis in the level of individual species and vegetation community. Climate change and the related increases in evapotranspiration threaten to make northern peatlands drier. The carbon sink function in peatlands is based on the delicate balance between the photosynthesis and decomposition. However, little is known about how existing and invading plant species will photosynthesize under drier conditions. We measured the species-level photosynthesis of vascular plants and mosses characteristic for the three peatland types (rich fen, poor fen, bog) within a 16-year water level drawdown (WLD) experiment from Lakkasuo peatland (61° 47’ N; 24° 18’ E), Finland. Species level photosynthesis was upscaled to site level using non-linear mixed effect models and species-vice leaf area data, specific leaf area data and moss cover and density data.

本数据集支撑本研究的核心结论，该研究量化了气候变化诱导的干旱对泥炭地光合作用在物种个体与植被群落层级的长期影响。
气候变化及伴随的蒸散量上升，正促使北方泥炭地趋于干旱。泥炭地的碳汇功能依托于光合作用与有机质分解间的微妙平衡。然而，目前学界对于现有及入侵植物物种在干旱条件下的光合表现仍知之甚少。
我们于芬兰拉克苏奥（Lakkasuo）泥炭地（坐标：61°47’ N；24°18’ E）开展了为期16年的水位下降（water level drawdown, WLD）实验，针对三类典型泥炭地类型——富营养沼泽（rich fen）、贫营养沼泽（poor fen）、藓类沼泽（bog）——中的维管植物（vascular plants）与苔藓（mosses），测定了其物种水平的光合速率。
研究采用非线性混合效应模型，结合物种单叶面积数据、比叶面积（specific leaf area）数据以及苔藓盖度与密度数据，将物种水平的光合观测数据升尺度至样地水平。