PROJECT DESCRIPTION
BACKGROUND
In ponds, wetlands and streams nutrients can be retained by natural processes. Wetlands also provide important habitats for plants and animals. Both of these qualities make ponds and wetlands important features in the agricultural landscape. But wetlands have decreased by some 90 % in this century alone. Increased nutrient loads, mainly due to the intensification of agriculture, and reduced wetland areas, together with canalisation of water streams, have resulted in eutrofication of lakes, streams and coastal waters. Up to now, the measures applied to combat eutrophication have been of a technical nature, addressing waste water treatment and the use of fertilisers in agriculture. But it seems that these measures are insufficient to solve the problem. The field work of this project focused on the catchment areas of two small rivers (Kävlingeå and Höjeå), which covers an area of 1500 square kilometers. The project involved the construction of wetlands and the establishment of buffer-strips in areas of intensive farming. These measures provided a complement to improvements to sewage plants and agricultural practices. In addition, pond, wetlands and buffer-strips functioned as refuges for many plants and animals.
OBJECTIVES
The longterm aim of the project was to reduce the nitrogen and phosphorus concentration in lakes and coastal areas, create more favourable conditions for animals and plants directly dependant on wetland habitats, increase opportunities for the public to access nature, and promote cooperation between authorities and farmers in supporting sustainable development. It was proposed that some 85 new dams and related wetland areas would be established, as well as 25 hectares of protected areas along the water streams.
RESULTS
During the project period 65 wetlands, with a total area of 74 ha, were constructed. Priority was given to areas with a high nutrient concentration in the water and with impoverished biological diversity. The size of the constructions ranged from 0.2 and 6.1 ha, with an average size of 1.1 ha. Buffer-strips (non-cultivated areas with a permanent vegetation of grass, herbs and bushes) were established along 59 km (36 ha) of the streams. Buffer-strips were given priority where the risk of erosion and surface run-off was great, along streams with intensively used farmland in close proximity to open water, and along stretches with a need for recreational areas. The experiences from the project were principally good, with considerable environmental gains achieved. Studies of nutrient retention in four of the wetlands indicated that wetlands are effective nutrient traps. Depending on nutrient load, the reduction capacity varied in the different wetlands. The nitrogen reduction ranged from between 400 and 4,000 kg/ha per year, with a mean of 1,700 kg/ha per year. The relative retention ranged from between 5 and 50%. The reduction of phosphorus varied from between 20 and 80 kg/ha per year, which corresponded to 10-45% of the incoming phosphorus. For suspended matter the reduction ranged from between 1,800 to 14,200 kg/ha per year, or 33 - 50%. Biological studies indicated the positive effect on biological diversity. During the first year after construction, the invertebrate fauna comprised a large number of species and individuals. Plant colonisation showed the same pattern. On average 32 wetland plants were found in each pond. Bird life also showed a quick response, with more than 25 breeding species observed in the studied ponds / wetlands. A total of 19 threatened species of animals and plants from the Swedish red list were recorded in the studies. Within the LIFE project a total of 100 ha of arable land was transformed into areas that are now available for recreation. In terms of cost, the average costs of construction of the measures established in this project were comparable to other available measures with similar environmental benefits.During the project period 65 wetlands, with a total area of 74 ha, were constructed. Priority was given to areas with a high nutrient concentration in the water and with impoverished biological diversity. The size of the constructions ranged from 0.2 and 6.1 ha, with an average size of 1.1 ha. Buffer-strips (non-cultivated areas with a permanent vegetation of grass, herbs and bushes) were established along 59 km (36 ha) of the streams. Buffer-strips were given priority where the risk of erosion and surface run-off was great, along streams with intensively used farmland in close proximity to open water, and along stretches with a need for recreational areas. The experiences from the project were principally good, with considerable environmental gains achieved. Studies of nutrient retention in four of the wetlands indicated that wetlands are effective nutrient traps. Depending on nutrient load, the reduction capacity varied in the different wetlands. The nitrogen reduction ranged from between 400 and 4,000 kg/ha per year, with a mean of 1,700 kg/ha per year. The relative retention ranged from between 5 and 50%. The reduction of phosphorus varied from between 20 and 80 kg/ha per year, which corresponded to 10-45% of the incoming phosphorus. For suspended matter the reduction ranged from between 1,800 to 14,200 kg/ha per year, or 33 - 50%. Biological studies indicated the positive effect on biological diversity. During the first year after construction, the invertebrate fauna comprised a large number of species and individuals. Plant colonisation showed the same pattern. On average 32 wetland plants were found in each pond. Bird life also showed a quick response, with more than 25 breeding species observed in the studied ponds / wetlands. A total of 19 threatened species of animals and plants from the Swedish red list were recorded in the studies. Within the LIFE project a total of 100 ha of arable land was transformed into areas that are now available for recreation. In terms of cost, the average costs of construction of the measures established in this project were comparable to other available measures with similar environmental benefits.
