Ain Kull

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.

Impact of climatic fluctuations and land use change on runoff and nutrient losses in rural landscapes

Results on the influence of land use and climatic changes on nutrient losses in the Porijogi river catchment, south Estonia, are presented, The main tendency in land use changes is a significant increase in abandoned lands (from 1.7% in 1987 to 12.5% in 1994), and a decrease in arable lands (from 41.8 to 22.5%). Significant climatic fluctuations were observed from 1951-1994. Warmer winters (increase from -7.9 to -5.8°C from 1950-1994) 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. Changes in water discharge and land use are also reflected in the mean annual runoff of total inorganic nitrogen (TIN) and total-P which decreased from 15.6 to 2.7 kg N ha -1 yr -1 (83%) and 0.32 to 0.21 kg P ha -1 yr -1 (34%), respectively during this period. However, nutrient losses from the forest subcatchment (upper course) did not change significantly. In contrast, the mean annual runoff of water, organic matter (after biological oxygen demand: BOD 5 ), TIN, total-P and SO 4 from cultivated subcatchments showed a significant decrease.

Climate-related change in terrestrial and freshwater ecosystems

Climate-related change in terrestrial and freshwater ecosystems. in: BACC Author Group, Assessment of Climate Change for the Baltic Sea Basin

The reclamation of the North Estonian oil shale mining area

The restoration of post-industrial landscapes is often a challenge regarding multifunctional land use issues. Multifunctionality is important from the point of view of both natural capital and socio-economic values (Haines-Young et al. 2006). On the other hand, restoration provides several opportunities for the optimal use of landscape functions (de Groot 2006). In this paper we analyse opportunities for the further multifunctional use of the oil shale mining region in North-Eastern Estonia.

Key sustainability issues and the spatial classification of sensitive regions in Europe

Cross-cutting environmental, social and economic changes may have harsh impacts on sensitive regions. To address sustainability issues by governmental policy measures properly, the geographical delineation of sensitive regions is essential. With reference to the European impact assessment guidelines from 2005, sensitive regions were identified by using environmental, social and economic data and by applying cluster analysis, United Nation Environmental Policy priorities and expert knowledge. On a regionalised ‘Nomenclature of Territorial Units for Statistics’ (NUTS) level and for pre-defined sensitive region types (post-industrial zones, mountains, coasts and islands) 31 % of the European area was identified as sensitive. However, the delineation mainly referred to social and economic issues since the regional data bases on environmental indicators are limited and do not allow the separation of medium-term vital classes of sensitive regions. Overall, the sensitive regions showed indicator values differing from the EU- 25 average.

A framework for habitat monitoring and climate change modelling: construction and validation of the Environmental Stratification of Estonia

Environmental stratifications provide the framework for efficient surveillance and monitoring of biodiversity and ecological resources, as well as modelling exercises. An obstacle for agricultural landscape monitoring in Estonia has been the lack of a framework for the objective selection of monitoring sites. This paper describes the construction and testing of the Environmental Stratification of Estonia (ESE). Principal components analysis was used to select the variables that capture the most amount of variation. Seven climate variables and topography were selected and subsequently subjected to the ISODATA clustering routine in order to produce relatively homogeneous environmental strata. The ESE contains eight strata, which have been described in terms of soil, land cover and climatic parameters. In order to assess the reliability of the stratification procedure for the selection of monitoring sites, the ESE was compared with the previous map of Landscape Regions of Estonia and correlated with five environmental data sets. All correlations were significant. The stratification has therefore already been used to extend the current series of samples in agricultural landscapes into a more statistically robust series of monitoring sites. The potential for applying climate change scenarios to assess the shifts in the strata and associated ecological impacts is also examined.

The changing landscapes of transitional economies: the Estonian coastal zone

In the coastal zone there is a transition from maritime to continental ecosystems which ensures a variety of ecotopes, high biological diversity and the potential to supply multiple services (ecological, economic and social). In addition to the natural environmental gradient, there is a remarkable footprint of human activities over thousands of years, which makes the coastal zone one of the most densely populated and economically exploited regions in the world. According to some scenarios, within 50 years more than 75% of the world’s human population will live in coastal zones (Small and Nicholls 2003).

The Gulf of Riga as a resource for wind energy — a project description

Wind is one of the main renewable energy resources. The planning of offshore wind farms is an ongoing process and the Gulf of Riga region is no exception. Accurate information on marine wind field with high spatial and temporal resolution is therefore needed. Rough ice conditions in the Gulf of Riga could impose a threat to the construction and operation of offshore wind parks. The Gulf of Riga is an important habitat area for marine mammals and birds. They could suffer the most from the operational activity of wind parks. People are afraid that their living standards may decrease. In several cases it remains uncertain how the planned wind parks contribute to the energy needs of adjacent counties. The project aims directly at producing policy-relevant and scientifically based information on wind energy fields, the most affected key natural species populations and social reactions of and economic benefits for the entire Gulf of Riga region. A decision-making tool based on spatial planning methods of the GIS environment will be developed to facilitate common planning for the exploitation of wind energy in the Gulf of Riga region. Dynamic maps of wind energy, ice conditions, migrating and wintering bird populations, and seals dating back to 2001 and having the projection to future climate will be produced. The indicators for spatial planning with regard to public attitude towards the development of wind parks and for the quantification of local plans concerning renewal energy consumption will be developed and integrated into the decision-making tool. The outputs of the project contribute to the elaboration of policy-relevant, environmental and socio-economic issues related to the exploitation of renewable energy. The project objectives are to provide the decision-makers and potential developers of wind parks in the Gulf of Riga with reliable marine wind information derived from high-resolution remote sensing data, coastal wind measurements and an ensemble of regional climate models. Wind fields will be complemented with the information on habitat areas for seals and wintering, migrating and breeding birds. Local people and authorities will be involved in the active process of the selection of suitable areas for wind parks through mapping their attitude and considering the requirements for the areas of renewable energy. The project partners are research institutes and funds for nature from Estonia and Latvia and the project period is from July 2010 until June 2012. This project is financed by the Estonia-Latvia Programme. Estonia-Latvia Programme is implemented according to the principles of the European Territorial Cooperation and it supports cross-border cooperation between Estonia and Latvia. It is funded by the European Regional Development Fund (ERDF), the Republic of Estonia and the Republic of Latvia.

Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots

Nitrous oxide (N2O) is a powerful greenhouse gas and the main driver of stratospheric ozone depletion. Since soils are the largest source of N2O, predicting soil response to changes in climate or land use is central to understanding and managing N2O. Here we find that N2O flux can be predicted by models incorporating soil nitrate concentration (NO3−), water content and temperature using a global field survey of N2O emissions and potential driving factors across a wide range of organic soils. N2O emissions increase with NO3− and follow a bell-shaped distribution with water content. Combining the two functions explains 72% of N2O emission from all organic soils. Above 5 mg NO3−-N kg−1, either draining wet soils or irrigating well-drained soils increases N2O emission by orders of magnitude. As soil temperature together with NO3− explains 69% of N2O emission, tropical wetlands should be a priority for N2O management.In a global field survey across a wide range of organic soils, the authors find that N2O flux can be predicted by models incorporating soil nitrate concentration (NO3–), water content and temperature. N2O emission increases with NO3– and temperature and follows a bell-shaped distribution with water content.

Residual Cadmium and Lead Pollution at a Former Soviet Military Airfield in Tartu, Estonia

This paper presents data on the levels and dynamics of cadmium (Cd) and lead (Pb) concentration in the plants, soil, and groundwater of the landing corridor and airfield of a former Soviet military air base in Estonia, immediately at the end of its 40-year service in 1992 and over the following 8 yr. In 1991-92 we found high Cd concentrations in the meadow plants Trifolium pratense and Dactylis glomerata (up to 56 mg kg−1). In 1993, the Cd concentration had dropped to 0.12–0.19 mg kg−1, and stabilized in 1997–2000 at 0.04 mg kg−1. Cd concentration in plants decreased significantly with increasing distance from the landing strip. Elevated Cd concentration (0.012 mg L−1) was found in the fuel of the TU-22M (Backfire) strategic bombers. In 1991 and 1993, leaded fuel influenced the mean Pb concentration in plants (1.8–4.2 mg kg−1). Average Pb concentration in both topsoil and the 30-40 cm soil horizon decreased between 1991 and 2000 from 28 to 6.5 and from 13.5 to 4.3 mg kg−1, respectively. Cd concentration in the topsoil of the landing corridor showed a significant increase between 1991 and 1993 (0.07–0.3 and 0.3–1.2 mg kg−1, respectively), but stabilized later on the level of 0.04 mg kg−1. The concentrations of both Pb and Cd in the soil were higher closer to the fuel bunkers. Current assessment of the movement of these metals from the vegetation to the soil and to groundwater is linked to potential leaching to the surrounding environment.