Riparian buffer zones in agricultural landscapes : Their status today and their future as an ecological tool in Sweden

Abstract: The application of intensive farming and cultivation practices, resulting in large-scale modification of the hydrology of streams and rivers and of the natural vegetation, has increased the need to find ways to mitigate the negative impact of this habitat degradation. Suitable design and creation of riparian buffer zones in agriculture areas, is by many considered the best remedial measure. Riparian buffer zones (RBZ) are protecting waterways from degradation as they can improve and maintain water quality by filtering sediment, nutrients, organic matter, and pesticides. At the same time RBZ constitute habitat for many animals and plants and their existence increases ecological connectivity, reduces erosion and creates recreational areas. The aim of the study was to investigate how agricultural companies in the Örebro County relate to riparian buffer zones along small streams and examine the actual status of riparian buffer zones, to see if they are designed by taking site characteristics into consideration. Furthermore, the aim was to check how consistent the approach of the agricultural companies is with the actual status of the riparian buffer zones as well as with the recommendations of the Swedish Board of Agriculture. In addition, the study aims to make conclusions if riparian buffer zones can be both an economical and an ecological tool in agricultural landscapes. The data collection consisted of two different parts. First, a quantitative survey including 20 agricultural companies was done to investigate how different agricultural companies relate to riparian buffer zones in connection with smaller streams. Second, a field study was carried out to examine the riparian buffer design along small streams in14 agricultural sites, where the stream width, the buffer width, the slope of the riparian zone, the soil texture and the vegetation were measured. The study results from both the questionnaire and the field study suggest that a riparian buffer zone of 3-10 m without overstory vegetation is preferred. These findings follow the Swedish Board of Agriculture recommendations regarding buffer width and overstory vegetation. Because of the small number of sites investigated and the small variation of the variables, no significant correlation was found between site characteristics and buffer zone widths. A larger project that will include more sites all over Sweden could test if the existing riparian zones are designed efficiently. However, an important finding of this study was that the farmers consider RBZ as an important ecological tool for maintaining water quality and for minimizing soil erosion and the use of fertilizers and pesticides. In addition, most of the agricultural companies would consider wider buffer zones and overstory vegetation if they would be compensated with government funding. RBZ can be an economic and ecological tool in agricultural landscapes in the future, if correct guidance to design and manage RBZ according to the site characteristics will be provided to the farmers.