Egle Köster

• PhD
• Project reseracher at University of Eastern Finland

Purpose Our study investigates how low-intensity surface fires affect the concentration of dissolved organic carbon (DOC) and the quality of dissolved organic matter (DOM) in boreal forest soils. DOC, a crucial and labile carbon (C) pool, is highly sensitive to disturbances such as wildfires, yet its post-fire dynamics remain poorly understood in b...

Northern peatlands are increasingly threatened by climate warming-induced hydrological changes, jeopardizing their pivotal role in maintaining the carbon balance. However, the impacts of drying and extreme weather events on the productivity of Sphagnum mosses — the dominant and most important carbon-sequestering plants in northern peatlands — remai...

Boreal forests are one of the most important biomes storing carbon (C). Wildfires burn yearly on average more than 1% of the boreal forest, and it is expected that the fire return intervals will shorten due to climate change. Fire is one of the most influential factors affecting soil organic matter quantity and quality, soil C pools, and presumably...

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...

Northern forest soils are a major carbon (C) reservoir of global importance. To estimate how the C balance in these soils will change, the roles of tree roots and soil microbes in C balance should first be decoupled. This study determined how the activity of heterotrophs and tree roots together with root-associated microbes in the rhizosphere varie...

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-...

The temperature changes for the future climate are predicted to be the most pronounced in boreal and arctic regions, affecting the stability of permafrost and fire dynamics of these areas. Fires can affect soil microbiome (archaea, bacteria, fungi, protists) directly via generated heat, while fire-altered soil properties have an indirect effect on...

Common practices and several studies have demonstrated the positive effect of biochar amendment on climate change mitigation, soil properties, and plant growth. We performed a greenhouse experiment to assess the potential of wood biochar to improve the properties of the growing media and the growth of seedlings in boreal tree species. We added will...

Key message During the first summer, wood biochar amendments increased soil temperature, pH, and soil CO 2 effluxes in a xeric boreal Scots pine forest. The increase of soil CO 2 efflux could be largely explained by increases in by soil temperature. Higher biochar application rates (1.0 vs 0.5 kg m −2) led to higher soil CO 2 efflux while the pyrol...

Wildfires strongly regulate carbon (C) cycling and storage in boreal forests and account for almost 10% of global fire C emissions. However, the anticipated effects of climate change on fire regimes may destabilize current C-climate feedbacks and switch the systems to new stability domains. Since most of these forests are located in upland soils wh...

One of the effects of climate change on boreal forest will be more frequent forest wildfires and permafrost thawing. These will increase the availability of soil organic matter (SOM) for microorganisms, change the ground vegetation composition and ultimately affect the emissions of biogenic volatile organic compounds (BVOCs), which impact atmospher...

Climate warming in arctic/subarctic ecosystems will result in increased frequency of forest fires, elevated soil temperatures and thawing of permafrost, which have implications for soil organic matter (SOM) decomposition rates, the CO 2 emissions and globally significant soil C stocks in this region. It is still unclear how decomposability and temp...

Wildfires burn approximately 1% of boreal forest yearly, being one of the most significant factors affecting soil organic matter (SOM) pools. Boreal forests are largely situated in the permafrost zone, which contains half of global soil carbon (C). Wildfires advance thawing of permafrost by burning the insulating organic layer and decreasing surfac...

Rising air temperatures and changes in precipitation patterns in boreal ecosystems are changing the fire occurrence regimes (intervals, severity, intensity, etc.). The main impacts of fires are reported to be changes in soil physical and chemical characteristics, vegetation stress, degradation of permafrost, and increased depth of the active layer....

Background and aims The addition of biochar to soil may offer a chance to mitigate climate change by increasing soil carbon stocks, improving soil fertility and enhancing plant growth. The impacts of biochar in cold environments with limited microbial activity are still poorly known. Methods In order to understand to what extent different types an...

Reindeer (Rangifer tarandus L.) are considered to be an important mammalian herbivore, strongly influencing Arctic lichen-dominated ecosystems. There is no wide knowledge about the effect of reindeer on greenhouse gas (GHG) fluxes in northern boreal forests. Ground vegetation plays an important role in absorbing nitrogen (N) and carbon dioxide (CO2...

Forest fires are one of the most important natural disturbances in boreal forests, and their occurrence and severity are expected to increase as a result of climate warming. A combination of factors induced by fire leads to a thawing of the near-surface permafrost layer in subarctic boreal forest. Earlier studies reported that an increase in the ac...

Fire is a major natural disturbance factor in boreal forests, and the frequency of forest fires is predicted to increase due to climate change. Nitrogen (N) is a key determinant of carbon sequestration in boreal forests because the shortage of N limits tree growth. We studied changes in N pools and fluxes, and the overall N balance across a 155-yea...

Relationship between total living biomass (above- and belowground biomass), above-ground tree biomass and ground vegetation biomass (sum of bottom and field layer vegetation) and time since the fire. Relationship between the nitrogen pools of total living biomass, above-ground tree biomass and ground vegetation and time since the fire. (TIF)

Data (the pools, fluxes and balance of nitrogen and nitrogen cycling genes). (XLSX)

In this work, we investigated how the reindeer grazing in subarctic boreal Scots pine forests and climate (air temperature and the amount of precipitation) affects soil temperature, soil water content, and ultimately the CO2 efflux from forest soils. The study was carried out in years 2013 and 2014, where 2013 was an extremely dry year (especially...

We compared the changes in aboveground biomass and initial recovery of C pools and CO2 efflux following fire disturbances in Scots pine (Pinus sylvesteris L.) stands with different time since stand-replacing fire. The study areas are located in hemiboreal vegetation zone, in north-western Estonia, in Vihterpalu. Six areas where the last fire occurr...

In boreal forest ecosystems fire, fungi and bacteria, and their interactions, have a pronounced effect on soil carbon dynamics. In this study we measured enzymatic activities, litter decomposition rates, carbon stocks and fungal and microbial biomasses in a boreal subarctic coniferous forest on a four age classes of non-stand replacing fire chronos...

Reindeer (Rangifer tarandus L.) are the most important large mammalian herbivores in Lapland, strongly affecting the dynamics of vegetation by grazing and trampling, and this is likely in turn to have consequences for the soil processes. We have investigated the changes occurring in above- and belowground biomasses, and soil C dynamics (CO2 efflux,...

Fire is one of the most important natural disturbances in the boreal forest. It strongly influences boreal forest structure and function, and alters microbial biomass and species composition e.g. by significantly reducing the abundance of decomposing fungi. We measured carbon stocks and estimated fungal biomass and soil carbon turnover in Pinus syl...

Factors that strongly affects the dynamics of ground vegetation in northern boreal forests are grazing and trampling by reindeers. Cladina stellaris, which is the main species of lichen in northern areas, is also an important food source for reindeer. The population of reindeer is high, and it has a considerable influence on the boreal forest ecosy...

Apomictic microspecies, for example those of the genus Alchemilla, are often difficult to distinguish. Still, their differences are thought to be persistent due to apomixis. Apomicts are argued to have general-purpose genotypes. The present study aims to assess the variation of morphological characters of Alchemilla depending on environmental condi...

Anthyllis vulneraria L. (Fabaceae) s. lato includes many cryptic taxa, ranging from 25 to 60 subspecies according to different authors. The delimitation of intraspecific taxa of A. vulneraria s. lato has always been complicated and inconsistent. Different data sets (multivariate analyses of morphological variation, allozymes, chloroplast SSRs and I...

Väitekirja elektrooniline versioon ei sisalda publikatsioone. Käesolevas töös analüüsiti võrdlevalt hariliku koldrohu (Anthyllis vulneraria) ja hariliku kortslehe (Alchemilla vulgaris) liigikomplekside morfoloogilist ja geneetilist varieeruvust. Hariliku koldrohu puhul mõõdeti kokku 26 tunnust looduslikest populatsioonidest kogutud isendeil ja lisa...