Effect of deforestation on water chemistry in the Ko?cieliska Valley in the Western Tatras in southern Poland

摘要

Effect of deforestation on water chemistry in the Ko?cieliska Valley in the Western Tatras in southern Poland. Bark beetle infestation is a leading source of local tree stand damage in Tatra National Park. In addition, hurricane-force winds also cause damage to tree stands, as in the case of the 2013 wind event in the Kopki Ko?cieliskie area of the Ko?cieliska Valley. The purpose of the study was to determine the effect of deforestation on seasonal changes in water chemistry, especially in the case of nitrate. The research was performed in the years 2015 and 2016 in seven catchments. The total number of monthly water samples was 175. Three forested catchments were selected along with two catchments deforested by high winds, one catchment deforested due to the action of the bark beetle, and one catchment affected by several different forms of deforestation. The following four types of measurements were performed in the field: pH, electrolytic conductance (EC_25°C), total mineralization (Mt). The following analyses were performed in the laboratory using DIONEX 2000 ion chromatography equipment – concentration of 14 ions in water samples: Ca2+, Mg2+, Na+, K+, NH₄+, Li+, HCO₃?, SO₄2?, Cl?, NO₂?, NO₃?, PO₄3?, Br?, F?. The concentration of NO₃? was many times higher in samples collected in deforested areas (x? = 16.53 mg·L?1) versus forested areas (x? = 3.06 mg·L?1). The share of NO₃? in overall water chemistry in catchments deforested by high wind events is more than three times higher (3.25% mval·L?1) than in forested catchments (1.07% mval·L?1), and almost twice as high as that for a catchment affected by the bark beetle (1.8% mval·L?1). In fact, it is high enough that the position of the nitrate ion in the sequence of anions in the deforested catchment shifts from HCO₃ > SO₄ > NO₃ > Cl (natural sequence occurring in forested carbonate-type catchments) to HCO₃ > NO₃ > SO₄ > Cl. In addition, the concentration of nitrate in stream water was found to be lower during the vegetation season, which is associated with the nitrogen intake of plant root systems in the summer season.