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This study aimed at evaluating the scale and costs of an environmentally and economically optimal set of Best Management Practices (BMPs) for agricultural pollution abatement in Lithuania in order to reach water protection goals in both inland and marine waters by distributing BMPs optimally in space, while taking climate change impacts into consideration. The assessment of BMPs impact involved the use of the SWAT model by applying two climate change representative concentration pathways (RCP4.5 and RCP8.5) and two time horizons (mid-century and end-century), as well as five BMPs (arable land conversion to grasslands, reduced fertilization, no-till farming, catch-crops, and stubble fields throughout winter). The optimization of the set of BMPs employed a genetic algorithm. The results suggest that the need for BMPs application will increase from 52% of agricultural areas in the historical period up to 65% by the end of century in the RCP8.5 scenario. This means less arable land could actually be used for crop production in the future if water protection targets are met. The high costs for reaching water targets would rise even more, i.e. by 173% for RCP4.5, and by 220% for the RCP8.5 scenario, reaching approximately 200 million euros/year. In such a context, the BMP optimization approach is essential for significant reduction of the costs. Winter cover crops and reduced fertilization show the best effectiveness and cost balance, and will therefore be essential in pursuing water protection targets., (© 2022. The Author(s).)

The study evaluated climate change impact on water flows and nutrient loads to surface water bodies in Lithuania by applying the SWAT model. Seven RCM and GCM combinations were selected and RCP4.5 and RCP8.5 climate change representative concentration pathways were selected for the study. The study concluded that an annual and winter increase in most river water flows are expected. The change will be driven by rising precipitation, mainly in the regions where it is already high. Less snow would result in less surface runoff, substituted by increased lateral and groundwater flows because of more water percolating through the soils. As a result, water flows could be expected to increase by 9.7% for RCP4.5 and by 35.4% for the RCP8.5 climate scenario by the end-century. Whereas sediment transport and phosphorus loads would tend to decline a little bit (median results are -11.4% and -5.6% respectively for the RCP4.5 scenario, -13.3% and -7.4% for the RCP8.5 by the end of century). Conversely, temperature driven nutrient mineralization and increased leaching are expected to cause a significant increase in nitrogen loads (by 23.1% for the RCP4.5 scenario and by 64.4% for the RCP8.5 by the end of century). Overall, it could be concluded that climate change related hydrometeorological and water quality changes were found to be the most profound for the end-century RCP8.5 climate change scenario. [ABSTRACT FROM AUTHOR]

The potential effects of climate change on nutrient (total N and total P) loads in four large-scale (A=2940-6771 km2) river basins in Lithuania were analyzed. The climate impact assessment was based on an ensemble of four (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) future climate projections, representing the averaged outputs from three (GFDL-CM3, NorESM1-M and HadGEM2-ES) global climate models. For each climate projection, near-future (2016-2035) and distant-future (2081-2100) time periods were compared to the baseline period (1986-2005) to distinguish future changes. The results have shown a decreasing trend in the annual nutrient loads in most of the studied rivers under the projected climate change. Seasonal changes in nutrient loads are also predicted with an increase occurring during the winter months and a fairly high decrease occurring in the spring and early summer months. These changes are consistent with the projected changes in the seasonal stream flow. [ABSTRACT FROM AUTHOR]

This study aimed at the evaluation of the change in the effectiveness of Best Management Practices (BMPs) for agricultural pollution control in terms of reduction of nutrient loads to surface water bodies in Lithuania in the context of climate change (CC). The SWAT model was used by applying two CC representative concentration pathways (RCP4.5 and RCP8.5), three time horizons (historical – 2000–2019, mid-century – 2040–2059, and end-century – 2080–2099), and five BMPs (arable land conversion to grasslands, reduced fertilization, no-till farming, catch-crops, and stubble fields throughout winter). The most effective (with the greatest nutrient reduction) BMPs include grasslands, stubble fields, and winter cover crops. No-plough farming and reduced fertilization BMPs appear to be the least effective ones. CC would increase the potential of reduced fertilization and conversion to grasslands BMPs up to 179% and 17%, respectively for total nitrogen (TN) reduction. Regarding total phosphorus (TP), the reduction potential would increase 226% for fertilization reduction, and remain approximate for grasslands (at median −4%). Due to winter reduction of loads, no-plough stubble fields, and winter cover crops would decrease by as much as − 50%, − 12% and − 26%, respectively for TN, and − 30%, − 11%, and − 17%, respectively for TP, compared to the historical period. The greatest change would be recorded for the most extreme CC scenario (RCP8.5) and the longest time horizon (end-century). The effectiveness of BMPs (except for no-plough) for TN load reduction would increase more, and on average would become greater in agriculture dominated areas (of central-northern Lithuania) than elsewhere, although the maximum reduction values would occur in western (and in some cases eastern) Lithuania (except for reduced fertilization). This suggests the importance of the application of the measures in both areas. BMPs (except for grasslands) are expected to have relatively little effect on the overall crop yield. • Climate change will alter the effectiveness of Best Management Practices. • Practices intervening surface runoff pathway is expected to lose effectiveness. • Nutrient reduction potential is predicted to increase in agricultural areas. [ABSTRACT FROM AUTHOR]

Abstract Climate change is likely to increasingly impact estuarine fish populations. Changes in water temperature or salinity can have deleterious effects on fish growth and behaviour. A decrease in the abundance of freshwater fish in the northern areas of the Curonian Lagoon has been attributed to increased salinity of inflowing water from the Baltic Sea. Thus, this study investigated the effects of possible changes in environmental salinity and temperature on the growth and behaviour of perch (Perca fluviatilis L.). Laboratory experiments revealed that brackish water (salinity 3 and 6) has neither a negative nor a positive effect on growth rates among perch young-of-the-year, when compared to freshwater (salinity 0). In contrast, results from behavioural experiments demonstrated that perch prefer to remain in brackish water (salinity 6) when given a choice between brackish and freshwater, and in warm water (18 °C) when given a choice between warm and cold water (12 °C). For this reason, the temperature rather than the salinity of inflowing colder brackish water from the Baltic Sea will be the most likely driver of short-term changes in fish distribution in the Curonian Lagoon. Highlights • Brackish water (salinity 3 and 6) has no effect on perch YOY growth rates. • Perch prefer to remain in brackish (salinity 6) water compared to fresh (0) water. • Perch prefer to remain in warm (18 °C) water compared cold (12 °C) water. • Temperature is the driver of changes in fish distribution in the Curonian Lagoon. [ABSTRACT FROM AUTHOR]

Climatic changes will influence the possibilities for agricultural production (e.g. longer growing season), agricultural management practices (e.g. changes in tillage, fertilization, increased use of fungicides) and runoff conditions, and thereby the losses of nutrients from agricultural fields to the environment. Nitrogen (N) is of particular interest in the Baltic Sea region because of its adverse effects on water quality. This paper gives an overview of the expected climatic changes in the Nordic–Baltic region, and the possible effects of these changes on runoff and N losses. Downscaled climate scenarios are used as a basis for evaluating the potential effects of climate change on hydrology, runoff and N losses. Examples from selected catchments in Nordic–Baltic water quality monitoring programmes, including data from extreme events, are presented and used for an assessment of the required adaptations. The analysis shows that there is a strong relationship between annual precipitation and runoff, and between runoff and N loss. The seasonality of precipitation, runoff and N loss indicate high losses outside the growing season. With climate change, increased precipitation is expected to occur mainly outside the growing season – in September–March – and result in increased runoff and thereby increased N losses. Existing data show that extreme events of precipitation have occurred in all seasons during the monitoring period, and have caused high runoff and high losses of N. With the expected increases in N losses, there is an urgent need for efficient measures to reduce N losses in order to fulfil the requirements of e.g. the EU Water Framework Directive (EU-WFD) and the Nitrates Directive and reduction of greenhouse gas emissions (GHG) from agriculture. [ABSTRACT FROM AUTHOR]