Effectiveness of Riparian Mitigation Measures for Enhancing Ecosystem Functions: A Holistic Summary of Selected Measures

Abstract

Water quality has declined globally over recent decades. The riparian interface is a key location for mitigation measures to support water quality and wider ecosystem services (ES). With new, multi-functional, riparian mitigation measures being designed and implemented, there is a need for evidence on the functioning of such measures with respect to delivery of ES. This study incorporated the judgements’ of experts, to assess the effectiveness of various riparian measures to deliver 14 individual ES. In total 24 experts (covering a range of expertise and nationalities) completed a bespoke questionnaire (and follow-up workshop) to assess their opinion on the effectiveness of 16 mitigation measures (e.g. grass buffers, wooded buffers, integrated buffers, sediment fence) to deliver the identified ES (e.g. water quality, habitats, carbon, recreation). The results highlight the significant variance in effectiveness of the 16 mitigation measures across the 14 individual ES. Wooded buffers were the most effective mitigation measure for seven of the fourteen individual ES and in most cases were deemed highly effective at delivering that service. Linear grass buffer strips consistently scored amongst the least effective measures. The results indicate that riparian mitigation measures are consistently less effective at delivering ES relating to pesticides and biomass production than they are for other ES. This study highlights that there is no ideal riparian mitigation measure capable of delivering the wide range of ES. Future policy/research could focus on developing and implementing bundles of mitigation measures along the source-pathway receptor continuum, by means of a “treatment train” approach.