Förändringar i markanvändning över tid och dess påverkan på vattenkvalitet
The EU Water Framework Directive has led that management follows the boundaries of natural catchments.
The Swedish waters suffer from a nutrient overload that originates mainly from diffuse sources such as agriculture and the subcatchment of Hackstabäcken in Vallentuna Kommun, just north of Stockholm, has been chosen for this study because of its high nutrient load and because it has undergone obvious changes in land use through the years.
In this study, the land use in 1902 is compared with the land use in 2011 in order to investigate if it has influenced the ability of the landscape to produce ecosystem services related to nutrient removal. These services will continue to be produced as long as the system is stable and resilient, but when landuse changes and manure from horses increases it will lead to disturbances that can convert a system from one regime in to a completely different one. That will result in loss, or degradation, of ecosystem services such as denitrification, phosphor sedimentation and adsorption, vegetation uptake and infiltration.
The results of this study are based upon area calculations of landuse from old maps from 1902 and 2011. Through these maps it becomes clear that the forests in Hackstabäcken, has increased with 170 ha together with an urbanization of 311 ha, at the same time as wetlands and arable land has diminished and lakes has suffered from reductions. Wetlands have been reduced with 76 ha and the ones remaining are of insufficient quality from a nutrient removal perspective.
Data from 1902 and 2011 regarding number of horses and bovines indicated a decrease in bovines and an increase in horses. This can mean a higher load of phosphorous since horses have an insufficient uptake, as opposed to bovines that regulate their uptake according to need.
This study points to the importance of sharing knowledge so the connections between landuse and water status is more commonly known. Which is an important part of the Water Framework Directive.
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