Open access publications in the SLU publication database

<p>The Swedish Environmental Protection Agency (SEPA) conducts Integrated Monitoring (IM) of the environmental status in forest ecosystems within the ”Forest” part of Sweden’s national environmental monitoring program. The monitoring is related to the Convention on ”LongRange Transboundary Air Pollution – LRTAP 1979” (UN/ECE). The Swedish Environmental Research Institute (IVL), the Geological Survey of Sweden (SGU) and the Department of Aquatic Sciences and Assessment (IVM) at the Swedish University of Agricultural Sciences (SLU) perform the investigations on behalf of the SEPA. The monitoring program includes ecosystem studies at catchment level with determinations of hydrological and chemical budgets as well as effects on biota, primarily the vegetation and studies of soil processes. The aims are to collect relevant background data from reference areas that can be used to separate anthropogenic disturbance of the ecosystem by air pollution from natural variation. Model simulations for prognoses of future environmental status are an important part of the program. IM also furnish possibilities to test models. The IM sites are located in protected areas where there has been little forestry activity for many decades. Atmospheric deposition of pollutants and anthropogenically induced climate change are the only human disturbances within the IM sites. This report documents the investigations carried out in 2019 on the four IM-sites Gårdsjön, Aneboda, Kindla and Gammtratten. The results are briefly described in the text, with some glimpses of the year’s results. The entire set of data and results are included in appendixes at the end of the report. The IM sites are base poor with permanently acidic conditions and high aluminium concentrations in soil water, groundwater and streams. Only Gammtratten exhibited inorganic aluminium concentrations at levels below those reported to be harmful to gill breathing organisms such as fish (Lydersen et al. 2002). At Aneboda, the trace metals Cu, Zn and Cd exhibited stream water concentrations below biologically harmful levels as well, while Pb slightly exceeds this limit (1,3 µg L-1 compared with 1,0 µg L-1). All sites except Aneboda, with somewhat elevated nitrate concentrations due to storm felling and bark beetle outbreaks, had low concentrations of inorganic nutrients. The coastal near location was reflected in the sea- salt influenced water chemistry at Gårdsjön, while the high concentrations of organic matter influenced the water quality at Aneboda. The water chemistry at Kindla seems to mirror shallow groundwater flow paths, which is common for Swedish forest land. Gammtratten is the least acidic area with an average pH of 5.6 and frequently occurring hydrogen carbonate in the stream water. At Gårdsjön, the ion fluxes were dominated by Na and Cl from the precipitation of sea spray, while the ion fluxes at Aneboda and Kindla were equally influenced by sea salt, sulphur deposition and internal biological processes. Organic matter played a significant role at Aneboda. At Gammtratten, internal biological processes determined the ion fluxes. At all IM sites, the annual mean temperature 2019 was 1.1–1.3°C higher than the long-term average (1961-1990). Especially the moths January-April and December had higher temperatures, while May and October was colder than normal. At Gårdsjön, the higher temperature has resulted in a prolonged vegetation period of approximately one month. The precipitation during 2019 was ca 200 mm higher than long-term average at Aneboda and Gårdsjön, normal at Kindla and ca 145 mm lower than at Gammtratten. The seasonal precipitation patterns were similar at the three southern sites with higher precipitation in winter, spring and early autumn compared with the long-term averages. During the initial months of the year, Gårdsjön exhibited higher precipitation as well, while it was lower than normal during June-November.<br></p>