Anna Laine

Peatland restoration is seen as a key nature‐based solution to tackle climate change and biodiversity loss. In Europe, nearly 50% of peatlands have been drained during the last decades, which have shifted their soils to carbon dioxide (CO 2 ) sources. Soils of forestry‐drained peatlands are known to vary from CO 2 sources to small sinks depending o...

Here we address the combined impact of multiple stressors that are becoming more common with climate change. To study the combined effects of a lower water table (WT) and increased frequency of drought periods on the resistance and resilience of peatlands, we conducted a mesocosm experiment. This study evaluated how the photosynthesis of lawn Sphag...

Management of drained peatlands may pose a risk or a solution on the way towards climate change mitigation, which creates a need to evaluate the current state of forestry-drained peatlands, the magnitude of degradation processes and indicators for carbon (C) loss. Using a large dataset (778 profiles, 891 peat samples, collected between 1977 and 201...

Plant-mediated CH 4 transport (PMT) is the dominant pathway through which soil-produced CH 4 can escape into the atmosphere and thus plays an important role in controlling ecosystem CH 4 emission. PMT is affected by abiotic and biotic factors simultaneously , and the effects of biotic factors, such as the dominant plant species and their traits, ca...

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...

After drainage for forestry and agriculture, peat extraction is one of the most important causes of peatland degradation. When peat extraction is ceased, multiple after-use options exist, including abandonment, restoration, and replacement (e.g., forestry and agricultural use). However, there is a lack of a global synthesis of after-use research. T...

Climate warming is leading to permafrost thaw in northern peatlands, and current predictions suggest that thawing will drive greater surface wetness and an increase in methane emissions. Hydrology largely drives peatland vegetation composition, which is a key element in peatland functioning and thus in carbon dynamics. These processes are expected...

Peatlands account for 15 to 30% of the world’s soil carbon (C) stock and are important controls over global nitrogen (N) cycles. However, C and N concentrations are known to vary among peatlands contributing to the uncertainty of global C inventories, but there are few global studies that relate peatland classification to peat chemistry. We analyze...

Peatlands constitute a significant soil carbon (C) store, yet the C gas flux components show distinct spatial variation both between and within peatlands. Determining the controls on this variability could aid in our understanding of the response of peatlands to global changes. In this study, we assess the usefulness of different vegetation related...

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. The aim of...

Peatlands are carbon dioxide (CO 2 ) sinks that, in parallel, release methane (CH 4 ). The peatland carbon (C) balance depends on the interplay of decomposer and CH 4 -cycling microbes, vegetation, and environmental conditions. These interactions are susceptible to the changes that occur along a successional gradient from vascular plant-dominated s...

Understanding how plant communities respond to increased evaporation and consequent water level drawdown (WLD) is critical for predicting the functioning of northern peatlands under climate change. Functional traits provide a quantitative link between vegetation and ecosystem functions and, therefore, constitute a useful concept for predicting resp...

Tämän selvityksen tarkoituksena on tuottaa kirjallisuuskatsaus ja siihen pohjautuvia johtopäätöksiä soiden ennallistamisen ilmasto-, vesistö- ja suoluontovaikutuksista. Selvitys pyrkii erityisesti kasaamaan yhteen uusimpia tutkimustuloksia ja aineistoja ennallistamisen vaikutuksiin liittyen ja toisaalta muodostamaan kokonaiskuvan laaja-alaisempaa s...

Methane (CH4) emissions from northern peatlands are projected to increase due to climate change, primarily because of projected increases in soil temperature. Yet, the rates and temperature responses of the two CH4 emission‐related microbial processes (CH4 production by methanogens and oxidation by methanotrophs) are poorly known. Further, peatland...

Most of the carbon accumulated into peatlands is derived from Sphagnum mosses. During peatland development, the relative share of vascular plants and Sphagnum mosses in the plant community changes, which impacts ecosystem functions. Little is known on the successional development of functional plant traits or functional diversity in peatlands, alth...

Current peatland models generally treat vegetation as static, although plant community structure is known to alter as a response to environmental change. Because the vegetation structure and ecosystem functioning are tightly linked, realistic projections of peatland response to climate change require the inclusion of vegetation dynamics in ecosyste...

The relative importance of global versus local environmental factors for growth and thus carbon uptake of the bryophyte genus Sphagnum—the main peat‐former and ecosystem engineer in northern peatlands—remains unclear. We measured length growth and net primary production (NPP) of two abundant Sphagnum species across 99 Holarctic peatlands. We tested...

In boreal peatlands felling and tree harvest are commonly carried out as part of peatland restoration. Stem only harvest is the principal harvest method and it leaves the live crown material (felling residue) containing most tree nutrients at the site. Whole tree harvest where felling residue is removed, is not favoured due to higher transport cost...

Vegetation and hydrology are important controlling factors in peatland methane dynamics. This study aimed at investigating the role of vegetation components, sedges, dwarf shrubs, and Sphagnum mosses, in methane fluxes of a boreal fen under natural and experimental water level drawdown conditions. We measured the fluxes during growing seasons 2001–...

Sphagnum is the major genus in northern peatlands that contributes to peat formation and carbon sequestration. Sphagnum growth in summer has been fairly well studied but the information about growth in autumn and winter is limited. Therefore, we studied how the growth of Sphagnum is seasonally distributed with a particular interest on possible wint...

Abstract. Current peatland models generally lack dynamic feedback between the plant community structure and the environment, although the vegetation dynamics and ecosystem functioning are tightly linked. Realistic projections of peatland response to climate change requires including vegetation dynamics in ecosystem models. In peatlands, Sphagnum mo...

Vegetation and hydrology are important controlling factors in peatland methane dynamics. This study aimed at investigating the role of vegetation components – sedges, dwarf-shrubs, and Sphagnum mosses – in methane fluxes of a boreal fen under natural and experimental water level drawdown conditions. We measured the fluxes during four growing season...

Questions Peatland ecosystems are a globally important carbon storage that is predicted to turn into a carbon source due to water level drawdown (WLD) associated with climate change. The predictions assume stable plant communities but how realistic is this assumption? If the vegetation is not stable, what are the nature and rate of changes? Locati...

p>Calcareous spring fens are among the rarest and most endangered wetland types worldwide. The majority of these ecosystems can be found at high latitudes, where they are affected by above average rates of climate change. Particularly winter temperatures are increasing, which results in decreased snow cover. As snow provides an insulating layer tha...

Northern peatlands form a major soil carbon (C) stock. With climate change, peatland C mineralization is expected to increase, which in turn would accelerate climate change. A particularity of peatlands is the importance of soil aeration, which regulates peatland functioning and likely modulates the responses to warming climate. Our aim is to asses...

It is well established that in ombrotrophic bogs, water-table depth (WTD) is the primary environmental control on testate amoeba distribution. However, the environmental controls on testate amoebae in minerotrophic fens are less well known and successional change in their assemblages associated with fen-bog peatland development has been scarcely in...

Northern wetlands with organic soil i.e., mires are significant carbon storages. This key ecosystem service may be threatened by anthropogenic activities and climate change, yet we still lack a consensus on how these major changes affects their carbon sink capacities. We studied how forestry drainage and restoration combined with experimental warmi...

Presentation

Decreasing snow cover in winter resulting from climate warming increases the incidence of freeze–thaw cycles (FTCs) in many ecosystems, including peatlands. As peatland eco- systems form a globally significant long-term carbon storage, understanding the effects of changing conditions in winter on carbon dynamics is essential. We studied how FTCs...

Table S3. Impact of drainage and restoration on the cover of plant functional types (PFTs), ANOVA results.

Table S4. Impact of drainage and restoration on the cover of plant functional types (PFTs), parameter estimates.

Table S1. Occurrence of species in study sites.

Table S2. Plant species used for carbon dioxide (CO2) assimilation and chlorophyll fluorescence (Fv/Fm) measurements.

Table S5. Impact of drainage and restoration on the light response of photosynthesis, ANOVA results.

Table S6. Impact of drainage and restoration on the light response of photosynthesis, Parameter estimates.

Table S7. Parameter estimates from the chlorophyll fluorescence (Fv/Fm) model.

Young coastal fens are rare ecosystems in the first stages of peatland succession. Their drainage compromises their successional development toward future carbon (C) reservoirs. We present the first study on the success of hydrological restoration of young fens. We carried out vegetation surveys at six young fens that represent undrained, drained,...

Peatlands provide globally important ecosystem services through climate and water regulation or biodiversity conservation. While covering only 3% of the earth's surface, degrading peatlands are responsible for nearly a quarter of carbon emissions from the land use sector. Bringing together world-class experts from science, policy and practice to hi...

Due to the climate of Finland, it has been suggested that the ecosystems located in Finland are especially sensitive to warming. Therefore, we compared 13 peatland systems throughout Finland along a latitudinal gradient from 69°N to 61°N to examine the response of methane production and methane oxidation with warming climate. Methane production occ...

Previous studies have shown that atmospheric nitrogen (N) deposition is detrimental to sphagna, which are a group of mosses that are important for carbon cycling in northern peatlands. Little is known about species interactions, such as relative responses of tall moss Polytrichum strictum Menzies ex Brid. and sphagna. We studied the effects of N de...

Question Measurements of ecosystem carbon (C) exchange are usually labour-intensive and expensive. In peatlands, these temporally and spatially limited measurements are often up-scaled over comparable ecosystems, such as ombrotrophic bogs, to provide an estimate for ecosystem level carbon dioxide (CO2) fluxes. Peatlands typically have moisture vari...

QuestionsSphagnum fuscum (Schimp.) Klinggr. is a characteristic species of the later stages of mire development. It is hypothesized that competition limits its success in earlier successional stages where higher mineral nutrient availability and wetter conditions favour species with a higher production rate and, therefore, a stronger ability to com...

Northern forests and peatlands are globally significant elements in carbon (C) cycling. Recent research has also highlighted the role of aquatic ecosystems in landscape C budgets. We measured contemporary carbon dioxide (CO2) and methane (CH4) exchange, lateral C transfer (dissolved organic carbon (DOC), CO2, CH4), and long-term C accumulation in a...

Model validation experiments are fundamental to ensure that the peat growth models correspond with the diversity in nature. We evaluated the Holocene Peatland Model (HPM) simulation against the field observations from a chronosequence of peatlands and peat core data. The ongoing primary peatland formation on the isostatically rising coast of Finlan...

Growing public interest in conserving peatlands has created a need for restoration and rapid indicators of progress in peat formation. Vegetation and hydrological indicators are commonly assessed, but changes in mineralization and decomposition rates might better indicate when peat formation is underway in restored peatlands. In Finland, we investi...

We compared the amount and composition of different aboveground biomass (BM) fractions of four mires with their net ecosystem CO2 exchange (NEE) measured by eddy covariance. We found clear differences in response of green biomass (GBM) of plant functional types (PFTs) to water table (WT), which resulted in larger spatial variation in GBM within a m...

Sphagnum mosses are widespread in areas where mires exist and constitute a globally important carbon sink. Their ecophysiology is known to be related to the water level, but very little is currently known about the successional trend in Sphagnum. We hypothesized that moss species follow the known vascular plant growth strategy along the successiona...

Question: How does restoration affect the hydrology and the understorey vegetation of managed pine fens? Location: Oligotrophic pine fens in Natura 2000 areas in Kainuu, eastern Finland. Methods: Eleven managed pine fens and eight pristine reference pine fens were chosen for the study in 2005. The managed fens, which had been drained for forestry d...

Questions: What impact do a wet and a dry growing season have on CO2 dynamics of mire plant communities along a primary succession gradient from the initiation stage to the bog stage? Location: Mires on a land uplift coast, Finland. Methods: We measured CO2 dynamics and vascular plant green area development on five mires that form a sequence of mir...

Although carbon (C) gas exchange during the summer largely determines the annual C balance of mires, the wintertime fluxes cannot be ignored. Decomposition continues as long as the soil is not frozen and a proportion of the gases produced during summer are also released during winter. We measured carbon dioxide (CO2) and methane (CH4) fluxes along...

Chamber method is commonly used to measure the CO2 exchange from plant communities. Due to low time resolution, actual measurements reflect only momentary CO2 exchange rates. Therefore, a common way to derive seasonal or annual estimates is to establish models describing the response of CO2 exchange to environmental variables, and then to reconstru...

Background/Question/Methods Peatland research community generally considers ombrotrophic mires, or bogs, as climax ecosystems that have developed via autogenic processes. While the term climax ecosystem has been widely criticized, it quite well describes bogs, which can persist for thousands of years. In addition to persistence, the bog vegetation...

A vegetation survey was carried out in a relatively intact Atlantic blanket bog in Southwest Ireland to study the vegetation patterns in relation to environmental variation, and to quantify the effect of artificial and natural borders on compositional variation. The data were analysed using canonical correspondence analysis. In terms of both vegeta...

This study aims to calculate the carbon balance of an Atlantic blanket bog in South-western Ireland between 2003 and 2008. Included in the carbon balance are the three main carbon components for peatlands: the two gaseous atmospheric carbon exchange components carbon dioxide (CO2) and methane (CH4) and the riverine loss of carbon as dissolved organ...

Peatlands play an important role in the global carbon (C) cycle, by acting as a large, long-term C sink. The C sink is sustained by a high water level that inhibits decomposition of organic matter. The C gas dynamics are therefore sensitive to changes in water level, and in climatically different years a peatland can vary from a sink to a source of...

Pristine peatlands are a significant source of atmospheric methane (CH4). Large spatio–temporal variation has been observed in flux rates within and between peatlands. Variation is commonly associated with water level, vegetation structure, soil chemistry and climatic variability. We measured spatial and temporal variation in CH4 fluxes in a blanke...

The surface of bogs is commonly patterned and composed of different vegetation communities, defined by water level. Carbon dioxide (CO2) dynamics vary spatially between the vegetation communities. An understanding of the controls on the spatial variation of CO2 dynamics is required to assess the role of bogs in the global carbon cycle. The water le...

Net ecosystem exchange (NEE) was measured in a patterned peatland with eddy covariance (EC) and chamber methods during a 12-month period. The peatland surface was composed of microforms characterized by a difference in water level and vegetation composition. The distribution of microforms varied spatially within the peatland. To achieve corresponde...