Water Regulating in Kenozero Taiga: Excess or Lack of Water and Where Does It Go?

Water-regulating ecosystem services (ESs) are a key factor in water supply for the population and the economy. In recent years, these ESs have been intensively included in regional and global assessments. However, the degree of knowledge of various water-regulating ESs and the availability of models for their estimation and mapping vary greatly. For example, most regional assessments currently do not take into account the ESs of moisture and precipitation recycling by forests which can lead to erroneous decisions on land use and forest management. To what extent is it possible to make adequate decisions on the basis of a partial assessment of the ESs? In this article, we discuss this problem using the example of boreal forests in the catchment of the Lake Kenozero in the north of the European part of Russia. Using the InVEST model, two ESs were quantified and mapped: water yield regulation due to evapotranspiration and water quality assurance due to prevention of soil erosion. The reduction in water yield due to evapotranspiration was estimated at 125 mm/year, and the prevention of soil erosion was estimated at 9.56 t/ha/year. Forest felling in the study area from 2007 to 2021 led to an increase in runoff and soil erosion by 6 mm/year and 0.03 t/ha/year, respectively. The hypothetical total instantaneous forest loss could lead to an increase in runoff and soil erosion by 71 mm/year and 2.44 t/ha/year, respectively. A tradeoff between these ESs was predictably identified as deforestation led to an increase in water yield and a deterioration in water quality due to soil erosion. The significance of a number of other water-regulating ESs for making regional decisions was expertly assessed. In particular, the importance of the ESs of precipitation recycling of sludge under climate change was discussed. Expanding the range of ESs under consideration increases the likelihood of choosing a protection strategy instead of a harvesting one in forest management.