Martin Forsius

• Research Professor
• Finnish Environment Institute

Browning of surface waters due to increased terrestrial loading of dissolved organic matter (DOM) is observed across the Northern Hemisphere. The effects influence several ecosystem services from freshwater productivity to water purification. Brownification is often explained by changes in large-scale anthropogenic pressures and ecosystem functioni...

Addressing global change requires standardised observations across all ecosystem spheres. To that end, the distributed Integrated European Long-Term Ecosystem, critical zone and socio-ecological Research Infrastructure (eLTER RI) strives for an optimal observational design of its over 200 in-situ facilities. Their spatial distribution should be unb...

Integrated long-term, in-situ observations are needed to document ongoing environmental change, to “ground-truth” remote sensing and model outputs and to predict future Earth system behaviour. The scientific and societal value of in-situ observations increases with site representativeness, temporal duration, number of parameters measured and compar...

The challenges posed by climate change, biodiversity loss, and land-use are deeply interconnected and integrated solutions are needed. This paper presents results from 11 contributions to a special issue covering topics of integrated modeling and spatial prioritization, mass-balance studies, Earth Observation techniques, research infrastructure dev...

We present regionally aggregated emissions of greenhouse gases (GHG) from five land cover categories in Finland: artificial surfaces, arable land, forest, waterbodies, and wetlands. Carbon (C) sequestration to managed forests and unmanaged wetlands was also assessed. Models FRES and ALas were applied for emissions (CO 2 , CH 4 , N 2 O) from artific...

Uncertainties are essential, yet often neglected, information for evaluating the reliability in forest carbon balance projections used in national and regional policy planning. We analysed uncertainties in the forest net biome exchange (NBE) and carbon stocks under multiple management and climate scenarios with a process-based ecosystem model. Samp...

The EU aims at reaching carbon neutrality by 2050 and Finland by 2035. We integrated results of three spatially distributed model systems (FRES, PREBAS, Zonation) to evaluate the potential to reach this goal at both national and regional scale in Finland, by simultaneously considering protection targets of the EU biodiversity (BD) strategy. Modelli...

Forest management methods and harvest intensities influence wood production, carbon sequestration and biodiversity. We devised different management scenarios by means of stakeholder analysis and incorporated them in the forest growth simulator PREBAS. To analyse impacts of harvest intensity, we used constraints on total harvest: business as usual,...

The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topic...

The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for sustainable development in the Artic-boreal region. Air quality in China and long-range transport of the atmospheric pollutants was also indicated as one of the most crucial topics o...

Climate change mitigation is a global response that requires actions at the local level. Quantifying local sources and sinks of greenhouse gases (GHG) facilitate evaluating mitigation options. We present an approach to collate spatially explicit estimated fluxes of GHGs (carbon dioxide, methane and nitrous oxide) for main land use sectors in the la...

The challenges posed by climate change and biodiversity loss are deeply interconnected. Successful co-managing of these tangled drivers requires innovative methods that can prioritize and target management actions against multiple criteria, while also enabling cost-effective land use planning and impact scenario assessment. This paper synthesises t...

Anthropogenic emissions of nitrogen (N) and sulphur (S) compounds and their long-range transport have caused widespread negative impacts on different ecosystems. Critical loads (CLs) are deposition thresholds used to describe the sensitivity of ecosystems to atmospheric deposition. The CL methodology has been a key science-based tool for assessing...

This article provides a synthesis of the latest observational trends and projections for the future of the Arctic. First, the Arctic is already changing rapidly as a result of climate change. Contemporary warm Arctic temperatures and large sea ice deficits (75% volume loss) demonstrate climate states outside of previous experience. Modeled changes...

Because of its serious large-scale effects on ecosystems and its transboundary nature, acid rain received for a few decades at the end of the last century wide scientific and public interest, leading to coordinated policy actions in Europe and North America. Through these actions, in particular those under the UNECE Convention on Long-range Transbo...

The target load concept is an extension of the critical load concept of air pollution inputs to ecosystems. The advantage of target loads over critical loads is that one can define the deposition and the point in time (target year) when the critical (chemical) limit is no longer violated. This information on the timing of recovery requires dynamic...

Forests regulate climate, as carbon, water and nutrient fluxes are modified by physiological processes of vegetation and soil. Forests also provide renewable raw material, food, and recreational possibilities. Rapid climate warming projected for the boreal zone may change the provision of these ecosystem services. We demonstrate model based estimat...

Atmospheric nitrogen (N) pollution is considered responsible for a substantial decline in plant species richness and for altered community structures in terrestrial habitats worldwide. Nitrogen affects habitats through direct toxicity, soil acidification, and in particular by favoring fast-growing species. Pressure from N pollution is decreasing in...

The international Long-Term Ecological Research Network (ILTER) encompasses hundreds of long-term research/monitoring sites located in a wide array of ecosystems that can help us understand environmental change across the globe. We evaluated long-term trends (1990–2015) for bulk deposition, throughfall and runoff water chemistry and fluxes, and cli...

Since its founding in 1993 the International Long-term Ecological Research Network (ILTER) has gone through pronounced development phases. The current network comprises 44 active member LTER networks representing 700 LTER Sites and ~ 80 LTSER Platforms across all continents, active in the fields of ecosystem, critical zone and socio-ecological rese...

Current climate warming is expected to continue in coming decades, whereas high N deposition may stabilize, in contrast to the clear decrease in S deposition. These pressures have distinctive regional patterns and their resulting impact on soil conditions is modified by local site characteristics. We have applied the VSD+ soil dynamic model to stud...

In order to simulate food web responses of small boreal lakes to changes in thermal stratification due to global warming, a 4 year whole-lake manipulation experiment was performed. Within that time, period lake mixing was intensified artificially during two successive summers. Complementary data from a nearby lake of similar size and basic water ch...

Empirical evidence based on integrated environmental monitoring including physical, chemical and biological variables is essential for evaluating the ecosystem benefits of costly emission reduction policies. The international multidisciplinary ICP IM (International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystem...

Essential Biodiversity Variables (EBVs) have been suggested to harmonize biodiversity monitoring worldwide. Their aim is to provide a small but comprehensive set of monitoring variables that would give a balanced picture of the development of biodiversity and the reaching of international and national biodiversity targets. Globally, GEO BON (Group...

Decomposition of plant litter is a key process for the transfer of carbon and nutrients in ecosystems. Carbon contained in the decaying biomass is released to the atmosphere as respired CO2, and may contribute to global warming. Litterbag studies have been used to improve our knowledge of the drivers of litter decomposition, but they lack comparabi...

The International Long-Term Ecological Research (ILTER) network comprises > 600 scientific groups conducting site-based research within 40 countries. Its mission includes improving the understanding of global ecosystems and informs solutions to current and future environmental problems at the global scales. The ILTER network covers a wide range of...

Ecosystem services have become an important concept in policy-making. Carbon (C) sequestration into ecosystems is a significant ecosystem service, whereas C losses can be considered as an ecosystem disservice. Municipalities are in a position to make decisions that affect local emissions and therefore are important when considering greenhouse gas (...

In this chapter an assessment of critical loads of sulphur and nitrogen for forests and (semi-)natural vegetation and their exceedances in the boreal and temperate region of the Northern Hemisphere (excluding the contiguous USA) is reported. Critical loads were estimated using steady-state mass balance methods (see Chap. 6). The influence of differ...

This chapter presents an overview of national-scale dynamic hydro-geochemical model applications to lake catchments in Norway, Sweden and Finland. Model simulations have been used to predict the recovery of soil and surface water chemistry in response to (1) decreased deposition of acidifying compounds, (2) the combined impacts of acidifying and cl...

Lake acidification in northern Europe provided some of the key impetus for the development of the critical loads approach during the 1980s. While major reductions in acidic deposition have been achieved during the last 20 years, through the application of this approach, regions with continued acidification and critical load exceedance persist aroun...

Landscape ecology can make a large contribution to ecosystem service (ES) studies since most ESs are place-based, and thus best evaluated, maintained, enhanced, and restored using integrative techniques at the landscape scale. Integration of field observation, modeling, and remote sensing are increasingly used to quantify and assess ES at different...

This report presents the results from the research project National Assessment of the Economics of Ecosystem Services in Finland (TEEB Finland). This pioneering project aimed to initiate a systematic national process for the integration of ecosystem services and related biodiversity (i.e. natural capital) into all levels of decision-making. TEEB fo...

We report on preparatory work to develop a virtual laboratory for ecosystem services, ESLab, and demonstrate its pilot application in southern Finland. The themes included in the pilot are related to biodiversity conservation, climate mitigation and eutrophication mitigation. ESLab is a research environment for ecosystem services (ES), which consid...

In 1999 we used the MAGIC (Model of Acidification of Groundwater In Catchments) model to project acidification of acid-sensitive European surface waters in the year 2010, given implementation of the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (LRTAP). A total of 202 sites in 10 regions in Europe were studied. The...

Chronic nitrogen (N) deposition is a threat to biodiversity that results from the eutrophication of ecosystems. We studied long-term monitoring data from 28 forest sites with a total of 1,335 permanent forest floor vegetation plots from northern Fennoscandia to southern Italy to analyse temporal trends in vascular plant species cover and diversity....

Uncertainty in future climate projections is widely recognised, yet few impact model studies explore the implications of this uncertainty on catchment hydrological and biogeochemical responses. Here, we report a novel model chain using HBV, INCA-C and MyLake to simulate runoff, snow dynamics, ice cover, soil moisture, lake thermal stratification an...

Prolongation of the growing season due to a warming climate could represent new opportunities for northern agriculture. Climatic and biotic constraints may, however, together with increasing risk for higher nutrient loads, challenge future crop production. The objective of this study was to speculate how a range of arable land use patterns, resulti...

Inland waters transport and emit into the atmosphere large amounts of carbon (C), which originates from terrestrial ecosystems. The effect of land cover and land-use practises on C export from terrestrial ecosystems to inland waters is not fully understood, especially in heterogeneous landscapes under human influence. We sampled for dissolved C spe...

Carter, Timothy R., Bärlund, Ilona, Fronzek, Stefan, Kankaanpää, Susanna, Kaivo-oja, Jari, Luukkanen, Jyrki, Wilenius, Markku, Tuomenvirta, Heikki, Jylhä, Kirsti, Kahma, Kimmo, Johansson, Milla, Boman, Hanna, Launiainen, Jouko, Laurila, Tuomas, Lindfors, Virpi, Tuovinen, Juha-Pekka, Aurela, Mika, Syri, Sanna, Forsius, Martin & Karvosenoja, Niko (20...

The International Long Term Ecological Research (ILTER) network can coordinate ecological research to provide observations of the ecosystem changes, and their socio-economic impacts on human societies at different scales. In this paper we demonstrate the importance of the ILTER network in the study and monitoring of environmental changes at a globa...

At a global level, it is estimated that nearly two-thirds of ecosystem services have been degraded in just fifty years. The additional stresses imposed by climate change will require extraordinary adaptation. This paper synthesises main result of a large Finnish project studying the vulnerability of key ecosystem services to climate change and the...

The metaphor of ecosystem service may blind us to the complexity of the natural systems which underpin and produce services. We, reviewed key references and propose a framework to illustrate the social system relying on the ecological system and the relationships between ecosystem composition, ecosystem structure, ecosystem processes and ecosystem...

Critical loads for acidification and eutrophication and their exceedances were determined for a selection of ecosystem effects monitoring sites in the Integrated Monitoring programme (UNECE ICP IM). The level of protection of these sites with respect to acidifying and eutrophying deposition was estimated for 2000 and 2020. In 2020 more sites were p...

A critical load is a deposition limit below which harmful effects for a given ecosystem do not occur; the approach has underpinned European sulfur (S) and nitrogen (N) effects-based emission reduction policies during the last two decades. Surface waters are an important resource in Finland, as such the development of models and determination of cri...

The environmental impact of different forest harvesting scenarios on soil nutrient status and water chemistry under current and future (IPCC A2) climate was evaluated for a random sample of lake catchments (n = 1066) covering Finland. Biomass removal scenarios were derived from a management-oriented large-scale forest model based on data from natio...

Climate change with higher air temperatures and changes in cloud cover, radiation and wind speed alters the heat balance and stratification patterns of lakes. A paired whole-lake thermocline manipulation experiment of a small (0.047 km2) shallow dystrophic lake (Halsjärvi) was carried out in southern Finland. A thermodynamic model (MyLake) was used...

Climate change is projected to increase mean temperature of northern lakes by the end of the twenty-first century. To simulate this scenario, during 2004–2007 we imposed artificial mixing in Halsjärvi, a small, polyhumic, boreal lake in southern Finland, to increase the depth of the thermocline by ~1.5m. The aims of the experiment were to evaluate...

Climate change with higher air temperatures and changes in cloud cover, radiation and wind speed alters the heat balance and stratification patterns of lakes. A paired whole-lake thermocline manipulation experiment of a small (0.047 km2) shallow dystrophic lake (Halsjärvi) was carried out in southern Finland. A thermodynamic model (MyLake) was used...

IntroductionEffects of climate change on nitrate leachingDissolved organic carbon (DOC)Saharan dustEffects of climate warming on soil chemical processesModelling the combined effects of climate change and acid depositionEffects on aquatic biotaConclusions References

IntroductionPhysical impactsChemical impactsConclusions References

For more than a decade, anthropogenic sulfur (S) and nitrogen (N) deposition has been identified as a key pollutant in the Arctic. In this study new critical loads of acidity (S and N) were estimated for terrestrial ecosystems north of 60 degrees latitude by applying the Simple Mass Balance (SMB) model using two critical chemical criteria (Al/Bc =...

A lake model (MyLake) has been used to simulate the impacts of the projected future (2071-2100) climate on the thermodynamic properties of a shallow and a deep lake in Finland. The model has been calibrated using a Bayesian Markov chain Monte Carlo (MCMC) simulation method. The model results show, among others, that the largest change in water temp...

Concentrations of dissolved organic carbon (DOC) are increasing in surface waters across Europe and North America. Two of the main mechanisms proposed to explain this increase are declines in sulphate (SO42-) deposition and changes in climate. Many of the reductions in SO42- have already occurred. Climate change-related effects are occurring now an...

The dynamic hydro-geochemical Model of Acidification of Groundwater in Catchments (MAGIC) was used to predict the response of 163 Finnish lake catchments to historic and future atmospheric deposition (1880–2100) and future tree harvesting practices. Deposition was assumed to follow current legislated European emission reduction policies (CLe) and a...

The dynamic hydro-chemical Model of Acidification of Groundwater in Catchments (MAGIC) was used to predict the response of 163 Finnish lake catchments to future acidic deposition and climatic change scenarios. Future deposition was assumed to follow current European emission reduction policies and a scenario based on maximum (technologically) feasi...

Several hypotheses have been proposed to explain recent, widespread increases in concentrations of dissolved organic carbon (DOC) in the surface waters of glaciated landscapes across eastern North America and northern and central Europe. Some invoke anthropogenic forcing through mechanisms related to climate change, nitrogen deposition or changes i...

The regional-scale trends (south, central and north Finland) in key acidification parameters over the period 1990–2003 were studied in lakes used for monitoring of acidification (157 lakes), and the catchment characteristics that best discriminate between lakes showing recovery (significant increase in alkalinity) and those not showing recovery (no...

The regional-scale trends (south, central and north Finland) in key acidification parameters over the period 1990–2003 were studied in lakes used for monitoring of acidification (157 lakes), and the catchment characteristics that best discriminate between lakes showing recovery (significant increase in alkalinity) and those not showing recovery (no...

Dissolved organic carbon concentrations ([DOC]) in surface waters are increasing in many regions of Europe and North America. These increases are likely driven by a combination of changing climate, recovery from acidification and change in severity of winter storms in coastal areas. INCA-C, a process-based model of climate effects on surface water...

The dynamic hydro-chemical Model of Acidification of Groundwater in Catchments (MAGIC) was used to predict the response of 163 Finnish lake catchments to future acidic deposition and climatic change scenarios. Future deposition was assumed to follow current European emission reduction policies and a scenario based on maximum (technologically) feasi...

A survey of 1,189 lakes was conducted in the fall of 1987 as part of the Finnish Research Project on Acidification (HAPRO). Most of the lakes for the survey (n=987) were randomly selected by a two-stage cluster sampling from two separate subregions, together covering the whole country. Lakes of sizes 0.01-10 km2 were included in the statistical sam...

The MAGIC model was used to evaluate the relative sensitivity of several possible climate-induced effects on the recovery of soil and surface water from acidification. A common protocol was used at 14 intensively studied sites in Europe and eastern North America. The results show that several of the factors are of only minor importance (increase in...

Trends in total organic carbon (TOC) concentrations over the period 1987-2003 were studied in 13 small forest lakes. Recovery from acidification (reduced SO(4) deposition) and long-term changes in runoff as potential drivers for the trends were examined. The results showed that TOC concentrations have increased throughout Finland. Ten of the 13 lak...

We designed artificial neural networks to model daily total organic carbon (TOC), total nitrogen (Ntot) and total phosphorus (Ptot) concentrations in streamwater and used the simulated concentrations to predict future fluxes under scenarios of climate change. The streams drain two forested catchments located in southern and eastern Finland. In the...

This report is a summary of the main results from the EU project 'Carbon' - Nitrogen Interactions in Forest Ecosystems' (CNTER). Since carbon (C) and nitrogen (N) are bound together in organic matter we studied both the effect of N deposition on C cycling in forest ecosystems, and the effect of C accumulation on N storage and release. Based on comp...

Proton (H+ ion) budgets were calculated for 17 forested sites in Europe using open field (bulk) and throughfall deposition and runoff or soil leachate data. Proton budgets integrate information about the complex chemical and biological processes that govern the generation or consumption of acidity in the ecosystem into a single parameter. The sites...

Acid rain! Dead fish! Forest dieback! In the 1980s and 1990s, these headlines appeared frequently in environmental news coverage in Europe and North America. Air pollutants from highly industrialized regions had caused widespread damage to pristine ecosystems far downwind. The victims-people living in regions such as eastern Canada and Norway-press...

Sulphur and nitrogen oxides emissions in Europe and deposition in Finland during the 21st century. Boreal Env. Res. 9: 185–198. This paper describes the development of European scenarios of sulphur and nitrogen oxide emissions and resulting depositions in Finland during the 21st century, based on the IPCC Special Report on Emissions Scenarios. The...

This study is based on a Finnish lake survey conducted in 1995, a dataset of 874 statistically selected lakes from the national lake register. The dataset was divided into subgroups to evaluate lake water-catchment relationships in different geographical regions and in lakes of different size. In the three southernmost regions, the coefficients of...

Concerns on the harmful effects of air pollutants in 1970s prompted international collaboration to combat air pollutants at their sources. The Convention on Long-range Transboundary Air Pollution was established in 1979, with subsequent setup of its working bodies. They included the Working Group on Effects, which laid the basis for the cooperative...

Long-term base cation balances (Ca, Mg and K) for forest mineral soils in Finland were calculated with mass balance methods. The aim of the study was to identify the areas in which weathering and base cation deposition do not support leaching and uptake of base cations by vegetation. The effect of stem harvesting and whole-tree harvesting on the ba...