Markus Erhard

Ecosystem service supply and vulnerability to global change in Europe

Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, “surplus land” for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.

Mapping and assessment of ecosystems and their services: An analytical framework for ecosystem assessments under action 5 of the EU biodiversity strategy to 2020

In the EU, many ecosystems and their services have been degraded 1,2 . Target 2 focuses on maintaining and enhancing ecosystem services and restoring degraded ecosystems by incorporating green infrastructure in spatial planning. This will contribute to the EUs sustainable growth objectives and to mitigating and adapting to climate change, while promoting economic, territorial and social cohesion and safeguarding the EUs cultural heritage. It will also ensure better functional connectivity between ecosystems within and between Natura 2000 areas and in the wider countryside. Target 2 incorporates the global Aichi target 15 agreed by EU Member States and the EU in Nagoya to restore 15% of degraded ecosystems by 2020. It is also a direct response to Aichi targets 2 and 14 of the Global Strategic Plan for Biodiversity, 2011-2020 of Convention of Biological Diversity 3 .

Projected changes in terrestrial carbon storage in Europe under climate and land use change, 1990-2100

Changes in climate and land use, caused by socio-economic changes, greenhouse gas emissions, agricultural policies and other factors, are known to affect both natural and managed ecosystems, and will likely impact on the European terrestrial carbon balance during the coming decades. This study presents a comprehensive European Union wide (EU15 plus Norway and Switzerland, EU*) assessment of potential future changes in terrestrial carbon storage considering these effects based on four illustrative IPCC-SRES storylines (A1FI, A2, B1, B2). A process-based land vegetation model (LPJ-DGVM), adapted to include a generic representation of managed ecosystems, is forced with changing fields of land-use patterns from 1901 to 2100 to assess the effect of land-use and cover changes on the terrestrial carbon balance of Europe. The uncertainty in the future carbon balance associated with the choice of a climate change scenario is assessed by forcing LPJ-DGVM with output from four different climate models (GCMs: CGCM2, CSIRO2, HadCM3, PCM2) for the same SRES storyline. Decrease in agricultural areas and afforestation leads to simulated carbon sequestration for all land-use change scenarios with an average net uptake of 17–38xa0Tg C/year between 1990 and 2100, corresponding to 1.9–2.9% of the EU*s CO2 emissions over the same period. Soil carbon losses resulting from climate warming reduce or even offset carbon sequestration resulting from growth enhancement induced by climate change and increasing atmospheric CO2 concentrations in the second half of the twenty-first century. Differences in future climate change projections among GCMs are the main cause for uncertainty in the cumulative European terrestrial carbon uptake of 4.4–10.1 Pg C between 1990 and 2100.

Analyzing the ecosystem carbon dynamics of four European coniferous forests using a biogeochemistry model

AbstractThis paper provides the first steps toward a regional-scale analysis of carbon (C) budgets. We explore the ability of the ecosystem model BIOME-BGC to estimate the daily and annual C dynamics of four European coniferous forests and shifts in these dynamics in response to changing environmental conditions. We estimate uncertainties in the model results that arise from incomplete knowledge of site management history (for example, successional stage of forest). These uncertainties are especially relevant in regional-scale simulations, because this type of information is difficult to obtain. Although the model predicted daily C and water fluxes reasonably well at all sites, it seemed to have a better predictive capacity for the photosynthesis-related processes than for respiration. Leaf area index (LAI) was modeled accurately at two sites but overestimated at two others (as a result of poor long-term climate drivers and uncertainties in model parameterization). The overestimation of LAI (and consequently gross photosynthetic production (GPP)), in combination with reasonable estimates of the daily net ecosystem productivity (NEP) of those forests, also illustrates the problem with modeled respiration. The model results suggest that all four European forests have been net sinks of C at the rate of 100–300 gC/m2/y and that this C sequestration capacity would be 30%–70% lower without increasing nitrogen (N) deposition and carbon dioxide (CO2) concentrations. The magnitude of the forest responses was dependent not only on the rate of changes in environmental factors, but also on site-specific conditions such as climate and soil depth. We estimated that the modeled C exchange at the study sites was reduced by 50%–100% when model simulations were performed for climax forests rather than regrowing forests. The estimates of water fluxes were less sensitive to different initializations of state variables or environmental change scenarios than C fluxes. n

An approach towards an estimate of the impact of forest management and climate change on the European forest sector carbon budget: Germany as a case study

Abstract The increasing concentration of greenhouse gases in the atmosphere and the consequent warming of the Earth’s surface presents a threat to the environment and economic development. This paper discusses how regional level impacts of transient climate change on forest growth are assessed with process-based models and how these responses are then scaled up to country and European level using national forest inventory data in combination with the European forest information scenario (EFISCEN) model. Stem wood volume and increment in the EFISCEN model is converted to whole tree biomass based on information from process-based models. Calculation of carbon in soil and in wood products is included in this approach. A preliminary carbon budget under current and changing climatic conditions, with current management regime for Germany, is presented and discussed. Although carbon stocks in trees, soil and products are increasing, we found that the German forest sector can sustain a carbon sink until 2050, but the sink gradually becomes smaller, declining from 1.7xa0Mg C/ha per year in 1995 to 0.7xa0Mg C/ha per year in 2050. This is due to ageing of forests, as sink activity in older forests is smaller than in younger forests. The sink activity in the soil increased slightly, but rate of storage in trees decreased more. Under changing climatic conditions, both carbon stock and sink activity in trees and soil were larger than under current climatic conditions. International processes, such as the United Nations Framework Convention on Climate Change (UNFCCC) and The Kyoto Protocol require integrated assessments of the role of forests and forestry on mitigation of climate change, but there is also a need for assessments of the impacts of climate change on forests. Research can provide information for decision-makers regarding the functioning of the system, potential risks and uncertainties. The upscaling approach described in this paper will be used later to investigate the impacts of selected forest management scenarios, under current and changing climatic conditions, on the forestry carbon budgets of 27 European countries.

THE IMPORTANCE OF AGE-RELATED DECLINE IN FOREST NPP FOR MODELING REGIONAL CARBON BALANCES

We show the implications of the commonly observed age-related decline in aboveground productivity of forests, and hence forest age structure, on the carbon dynamics of European forests in response to historical changes in environmental conditions. Size-dependent carbon allocation in trees to counteract increasing hydraulic resistance with tree height has been hypothesized to be responsible for this decline. Incorporated into a global terrestrial biosphere model (the Lund-Potsdam-Jena model, LPJ), this hypothesis improves the simulated increase in biomass with stand age. Application of the advanced model, including a generic representation of forest management in even-aged stands, for 77 European provinces shows that model-based estimates of biomass development with age compare favorably with inventory-based estimates for different tree species. Model estimates of biomass densities on province and country levels, and trends in growth increment along an annual mean temperature gradient are in broad agreement with inventory data. However, the level of agreement between modeled and inventory-based estimates varies markedly between countries and provinces. The model is able to reproduce the present-day age structure of forests and the ratio of biomass removals to increment on a European scale based on observed changes in climate, atmospheric CO2 concentration, forest area, and wood demand between 1948 and 2000. Vegetation in European forests is modeled to sequester carbon at a rate of 100 Tg C/yr, which corresponds well to forest inventory-based estimates.

Regional impact assessment on forest structure and functions under climate change—the Brandenburg case study

Abstract A forest simulation model has been applied in a regional impact assessment to investigate impacts of climate change on forest structure and function in the Federal state of Brandenburg, Germany. The forest model FORSKA-M was linked to a GIS that included soil, groundwater table and land-use maps. Two climate scenarios (current climate and a climate change of 1.5xa0K temperature increase which is combined with a precipitation decrease of 10–20% on average) for 40 meteorological stations in and around Brandenburg were used to assess the sensitivity of species composition to climate change. Furthermore, the implications of vegetation changes for other forest functions were analysed by means of several indicators. To evaluate the impacts of climate change on biodiversity, measures of species diversity (Shannon’s and Simpson’s index) and habitat and structural diversity (Seibert’s index) were applied. The evaluation of impacts on groundwater recharge of natural and managed forests was carried out using the soil water balance model of FORSKA-M. At first, model simulations of the potential natural vegetation (PNV) on the whole area of Brandenburg with different climate scenarios were analysed. The results indicated that climatic warming would lead to a shift in the natural species composition in Brandenburg towards more drought tolerant species. The simulated diversity of the forests would be reduced, and groundwater recharge would be decreased. The majority of forests in the state of Brandenburg have been managed intensively in the past. At present, large areas of Brandenburg’s forests are dominated by pure stands of Scots pine, but current forest management practice aims at increasing the share of deciduous and mixed forests. In order to analyse the possible consequences of climate change on forest management, forest inventory data were used to initialise FORSKA-M with representative forest stands. Simulation experiments with three different management scenarios showed that the short to mid-term effects of climatic change in terms of species composition were not as severe as expected. However, the comparison of different diversity measures indicates a decrease in the species diversity in contrast to an increase in habitat diversity under climate warming. Furthermore, a decrease in productivity and groundwater recharge was simulated under the climate change scenario. The regional impact assessment corroborated the high sensitivity of natural forests in the region to the projected climatic change and it underlined the importance of adaptive management strategies to help forestry to cope with climatic change.

Mapping and Assessment of Ecosystems and their Services: Indicators for ecosystem assessments under Action 5 of the EU Biodiversity Strategy to 2020

Environment Europe Direct is a service to help you find answers to your questions about the European Union Summary The second MAES report presents indicators that can be used at European and Member States level to map and assess biodiversity, ecosystem condition and ecosystem services according to the Common International Classification of Ecosystem Services (CICES v4.3). This work is based on a review of data and indicators available at national and European level and is applying the MAES analytical framework adopted in 2013.

Simulation of tree and stand development under different environmental conditions with a physiologically based model

Abstract A simulation approach is used to describe annual tree growth and tree mortality from the output of a physiologically based model (FORSANA). Height and diameter growth are calculated directly from the amount of carbon allocated to sapwood by considering an optimum height/diameter ratio, which depends on stand density. Tree mortality is defined by means of a relation between net primary production and carbon loss due to compartment senescence. Thus, all responses to environmental conditions considered in the physiological part of the model are implicitly considered in the stand development description. The dynamic simulation of stand properties, on the other hand, is required to apply the physiological based process description to long-term assessments. The model is used to describe height and diameter development of three Scots pine ( Pinus sylvestris L.) stands in eastern Germany which are exposed to different levels of nitrogen deposition and SO 2 air pollution. Results are compared with tree ring analysis covering a period of 27 years. For further evaluation, the model is initialised with forest inventory data of 288 pine stands and is run over 23 years using daily weather and deposition data as well as fertilisation information as input. The results are compared to data from a second inventory of the same stands. This comparison is conducted separately for regions exposed to high and low deposition. The model represents annual height and diameter development at two of the three selected sites. With respect to the third site, considerable disturbances in the early years of stand development are assumed to be responsible for the unusual growth trend. The regional evaluation of the model yields correlation coefficients with forest inventory data between 0.57 and 0.86, with a generally better fit on diameter and stemwood volume than height. The approach demonstrates the uncertainty of estimations which are based on investigations at only few sites, and is discussed as a possible method for regional assessment of forest development under environmental change.

Analysing Seasonal Differences between a Soil Water Balance Model and in Situ Soil Moisture Measurementsat Nine Locations Across Europe

We compared soil moisture from the soil water balance model for European Water Accounting (swbEWA) with in situ observations from nine locations in three European climatic zones (continental, Mediterranean and maritime temperate), for different periods between 2003 and 2011. Despite the simplicity of the swbEWA model, the patterns of temporal changes in soil moisture content are well represented at all locations. Annual averages show that the model overestimates the soil moisture content, and that overestimations are the smallest when measurements are obtained from more than one depth. These results suggest that the relationship between simulated and observed soil moisture also depends on the number of measurements and the depth over which they are taken. In the continental climate, where snow cover and frozen soil influence soil moisture, we observe higher root mean square error values in winter months. However, in the Mediterranean and maritime temperate climates, we do not observe clear common seasonal patterns in the soil moisture profile, which makes it difficult to relate the model’s accuracy to climate. With the percentage of correctness and probability of detection measures, we tested the model performance in simulating dry versus non-dry events. The percentage of the correctly classified dry and non-dry events is higher than 84 % at all locations, whereas the probability to detect dry events is significantly lower, exceeding 50 % at only four out of nine stations. The frequency distribution of consecutive days with dry soil (CDDS) confirms the model performance: higher number of short dry periods (with less than 20 days of soil moisture near wilting point) are reproduced and observed in continental climates, whereas long dry periods (longer than 50 days) are noted in the Mediterranean climate. Overall, the statistical measures suggest that the model produces the highest accuracy in summer months at the stations in continental climates, whereas in the Mediterranean climate, the accuracy is slightly higher in the colder seasons.