Ülo Mander

Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon

Bioenergy from crops is expected to make a considerable contribution to climate change mitigation. However, bioenergy is not necessarily carbon neutral because emissions of CO2, N2O and CH4 during crop production may reduce or completely counterbalance CO2 savings of the substituted fossil fuels. These greenhouse gases (GHGs) need to be included into the carbon footprint calculation of different bioenergy crops under a range of soil conditions and management practices. This review compiles existing knowledge on agronomic and environmental constraints and GHG balances of the major European bioenergy crops, although it focuses on dedicated perennial crops such as Miscanthus and short rotation coppice species. Such second‐generation crops account for only 3% of the current European bioenergy production, but field data suggest they emit 40% to >99% less N2O than conventional annual crops. This is a result of lower fertilizer requirements as well as a higher N‐use efficiency, due to effective N‐recycling. Perennial energy crops have the potential to sequester additional carbon in soil biomass if established on former cropland (0.44 Mg soil C ha−1 yr−1 for poplar and willow and 0.66 Mg soil C ha−1 yr−1 for Miscanthus). However, there was no positive or even negative effects on the C balance if energy crops are established on former grassland. Increased bioenergy production may also result in direct and indirect land‐use changes with potential high C losses when native vegetation is converted to annual crops. Although dedicated perennial energy crops have a high potential to improve the GHG balance of bioenergy production, several agronomic and economic constraints still have to be overcome.

Multifunctional land use: meeting future demands for landscape goods and services

Cultural landscapes are multifunctional through their simultaneous support of habitat, productivity, regulatory, social, and economic functions (de Groot 1987; Bastian and Schreiber 1999). Heterogeneity is a basic characteristic of landscape, and this heterogeneity implies the capacity of landscape to support various, sometimes contradictory functions simultaneously. Many elements in cultural landscapes have a multifunctional character, and this has been thoroughly studied. For instance, hedgerows (Burel 1996), forests (Pandey 2002), wetlands and their ecotones (Kruk 2003), riparian buffer zones (Mander et al. 2005) and various grassland ecosystems (Gibon 2005), which control various energy and material fluxes in the landscape, protect biodiversity and provide recreational opportunities for people, are classical examples of multifunctional landscape elements. Land use is the key activity which determines the performance of landscapes with respect to socio-economic functions such as land based production, infrastructure and housing. The degree of integration between these socio-economic functions and environmental functions including natural resources protection depends on the patterns and intensities of land use (Wiggering et al. 2003).

Nutrient runoff dynamics in a rural catchment: Influence of land-use changes, climatic fluctuations and ecotechnological measures

Abstract The main trend in land-use changes in the Porijogi River catchment, south Estonia, is a significant increase in abandoned lands (from 1.7% in 1987 to 10.5% in 1997), and a decrease in arable lands (from 41.8 to 23.9%). Significant climatic fluctuations occurred during the last decades. Milder winters (increase of air temperature in February from −7.9 to −5.5°C during the period 1950–1997) and a change in the precipitation pattern have influenced the mean annual water discharge. This results in more intensive material flow during colder seasons and decreased water runoff in summer. During the period 1987–1997 the runoff of total-N, total-P, SO4, and organic material (after BOD5) decreased from 25.9 to 5.1, from 0.32 to 0.13, from 78 to 48, and from 7.4 to 3.5 kg ha−1 year−1, respectively. Most significant was a 4–20-fold decrease in agricultural subcatchments while in the forested upper-course catchment the changes were insignificant. Variations of total-N, and total-P runoff in both the entire catchment and its agricultural subcatchments are well described by the change of land use (including fertilization intensity), soil parameters and water discharge. In small agricultural subcatchments the rate of fertilization was found to be the most important factor affecting nitrogen runoff, while land-use pattern plays the main role in larger mosaic catchments. Ecotechnological measures (e.g. riparian buffer zones and buffer strips, constructed wetlands) to control nutrient flows from agricultural catchments are very important.

Wetland treatment at extremes of pH: A review

Constructed wetlands are an established treatment technology for a diverse range of polluted effluents. There is a long history of using wetlands as a unit process in treating acid mine drainage, while recent research has highlighted the potential for wetlands to buffer highly alkaline (pH>12) drainage. This paper reviews recent evidence on this topic, looking at wetlands treating acidic mine drainage, and highly alkaline leachates associated with drainage from lime-rich industrial by-products or where such residues are used as filter media in constructed wetlands for wastewater treatment. The limiting factors to the success of wetlands treating highly acidic waters are discussed with regard to design practice for the emerging application of wetlands to treat highly alkaline industrial discharges. While empirically derived guidelines (with area-adjusted contaminant removal rates typically quoted at 10 g Fe m(2)/day for influent waters pH>5.5; and 3.5-7 g acidity/m(2)/day for pH>4 to <5.5) for informing sizing of mine drainage treatment wetlands have generally been proved robust (probably due to conservatism), such data exhibit large variability within and between sites. Key areas highlighted for future research efforts include: (1) wider collation of mine drainage wetland performance data in regionalised datasets to improve empirically-derived design guidelines and (2) obtaining an improved understanding of nature of the extremophile microbial communities, microbially-mediated pollutant attenuation and rhizospheral processes in wetlands at extremes of pH. An enhanced knowledge of these (through multi-scale laboratory and field studies), will inform engineering design of treatment wetlands and assist in the move from the empirically-derived conservative sizing estimates that currently prevail to process-based optimal design guidance that could reduce costs and enhance the performance and longevity of wetlands for treating acidic and highly alkaline drainage waters.

Holistic aspects in landscape development: a scenario approach

Abstract A holistic approach to landscape development includes biological, physical and human components. This approach becomes even more useful when landscapes face rapid change. This paper is based on a landscape model ( Keisteri, 1990 ) that consists of visible material features, perceivable non-material features, and underlying processes. Landscape change is sometimes unpredictable because the transformation consists of autonomous as well as human-steered processes. This study argues that study of the perceivable, non-material features and underlying processes influencing landscape change can be used to create scenarios that predict the visible, material changes in the landscape. As an example, a case study has been carried out in Obinitsa, Estonia. Four scenarios were created to project the possible landscape changes in that marginal area. After that the locals’ preferences of these scenario were tested. Of the different development options people prefer those which resemble the identity of the landscape or those which, although introducing larger changes, create a feeling of certainty, predictability, welfare and well-being.

Gaseous fluxes in the nitrogen and carbon budgets of subsurface flow constructed wetlands

In 2001 and 2002, fluxes of N(2)O, CH(4), CO(2) and N(2) were measured in two constructed wetlands (CW) for domestic wastewater treatment in Estonia. The difference between the median values of N(2)O, CH(4), and N(2) fluxes in the horizontal subsurface flow (HSSF) CWs was non-significant, being 1.3-1.4 and 1.4-4.1 mg m(-2) d(-1) for N(2)O-N and CH(4)-C, and 0.16-0.17 g N m(-2) d(-1) for N(2)-N respectively. The CO(2)-C flux was significantly lower (0.6 g C m(-2) d(-1)) in one of the HSSF filters of a hybrid CW, whereas the single HSSF and VSSF filters emitted 1.7 and 2.0 g C m(-2) d(-1). The median value of CH(4)-C emission in CWs varied from 1.4 to 42.6 g C m(-2) d(-1), being significantly higher in the VSSF filter beds. We also estimated C and N budgets in one of the HSSF CWs (312.5 m(2)) for 2001 and 2002. The total C input into this system was similar in 2001 and 2002, 772 and 719 kg C year(-1), but was differently distributed between constituent fluxes. In 2001, the main input flux was soil and microbial accumulation (663 kg C year(-1) or 85.8% of total C input), followed by plant net primary production (NPP) (10.2%) and wastewater inflow (3.9%). In 2002, 55.7% of annual C input was bound in plant NPP, whereas the increase in soil C formed 28.5% and wastewater inflow 15.7%. The main C output flux was soil respiration, including microbial respiration from soil and litter, and the respiration of roots and rhizomes. It formed 120 (97.5%) and 230 kg C year(-1) (98.2%) in 2001 and 2002 respectively. The measured CH(4)-C flux remained below 0.1% of total C output. The HSSF CW was generally found to be a strong C sink, and its annual C sequestration was 649 and 484 kg C year(-1) per wetland in 2001 and 2002 respectively. However, negative soil and microbial accumulation values in recent years indicate decreasing C sequestration. The average annual N removal from the system was 38-59 kg N year(-1) (46-48% of the initial total N loading). The most important flux of the N budget was N(2)-N emission (22.7 kg in 2001 and 15.2 kg in 2002), followed by plant belowground assimilation (2.3 and 11.9 kg N year(-1) in 2001 and 2002), and above-ground assimilation (1.9 and 9.2 kg N year(-1), respectively). N(2)O emission was low: 0.37-0.60 kg N year(-1)(.).

Ecological and low intensity agriculture as contributors to landscape and biological diversity

Possible impacts of ecological farming and low intensity conventional agriculture on landscape values such as biodiversity, landscape diversity and nutrient flows are analysed. Literature data and the results of several case studies are summarised. The results show that ecological farming significantly increases biological and landscape diversity and decreases the risk of nutrient leaching and soil erosion. Marginal areas, where low intensity agriculture creates less pollution load and supports biodiversity, have the most potential for conversion to ecological agriculture. However, owing to the greater impacts of ecological agriculture on biodiversity in intensively managed agricultural areas, ecological farming should be developed within the core areas of intensive agricultural production.

Phosphorus removal using Ca-rich hydrated oil shale ash as filter material--the effect of different phosphorus loadings and wastewater compositions.

We studied the phosphorus (P) binding capacity of Ca-rich alkaline filter material - hydrated oil shale ash (i.e. hydrated ash) in two onsite pilot-scale experiments (with subsurface flow filters) in Estonia: one using pre-treated municipal wastewater with total phosphorus (TP) concentration of 0.13-17.0 mg L(-1) over a period of 6 months, another using pre-treated landfill leachate (median TP 3.4 mg L(-1)) for a total of 12 months. The results show efficient P removal (median removal of phosphates 99%) in horizontal flow (HF) filters at both sites regardless of variable concentrations of several inhibitors. The P removal efficiency of the hydrated ash increases with increasing P loading, suggesting direct precipitation of Ca-phosphate phases rather than an adsorption mechanism. Changes in the composition of the hydrated ash suggest a significant increase in P concentration in all filters (e.g. from 489.5 mg kg(-1) in initial ash to 664.9 mg kg(-1) in the HF filter after one year in operation), whereas almost all TP was removed from the inflow leachate (R(2) = 0.99). Efficiency was high throughout the experiments (median outflow from HF hydrated ash filters 0.05-0.50 mg L(-1)), and P accumulation did not show any signs of saturation.

Development of European landscapes

This editorial paper analyses comprehensive information presented on International Association for Landscape Ecology (IALE) European Conference “Development of European Landscapes” jointly organized by the University of Stockholm and University of Tartu, held in both Stockholm, Sweden, 30 June–2 July 2001, and in Tartu, Estonia, 3–6 July 2001. Selected conference findings from oral presentations and posters are presented here. About 130 oral presentations and 50 posters representing 33 countries were presented during the conference. Sixteen papers published as part of this special issue of Landscape and Urban Planning, and summarized here, deal with general and methodological principles of the landscape analysis and research, and also, present case studies on landscape ecology, planning and management from various European countries.

Ecosystem services of peatlands: Implications for restoration

The aim of this overview paper is to analyse the inclusion and use of the ecosystem services concept in scientific studies of degraded peatlands and peatland restoration. Publications indexed by the Institute of Science Information (ISI) Web of Science (WoS) from 1980 to October 2009 were analysed. Word combinations relevant to peatland ecosystem services in the title, keywords and abstract were used. We followed the division of ecosystem services into four categories: supporting, regulating, provisioning and cultural, as provided by the Millennium Ecosystem Assessment (2005). The analysis indicated that the concept of ecosystem services is not referred to explicitly in ISI WoS studies on peatland restoration. The interpretation of the content identified using search phrases related to various beneficial functions of peatlands showed that they mainly include information on regulating and supporting ecosystem services critical to sustaining vital ecosystem functions that deliver benefits to people. There are only a few articles addressing provisioning and cultural ecosystem services. One of the key issues concerning the effect of peatland restoration in the provisioning of ecosystem services is the balance of greenhouse gases and their role in global climate regulation.