What are buffer strips and how can they help?
Catchment riparian areas are considered key zones in which to target mitigation measures aiming at interrupting the movement of pollutants from agricultural land to surface waters. Hence, unfertilised buffer strips have become a widely studied and implemented ‘edge of field’ mitigation measure assumed to provide an effective physical barrier against nitrogen, phosphorus and sediment transfer across them.
The James Hutton Institute has led an initiative to look at wider aspects of managing buffers to achieve a number of multiple diffuse pollution mitigation, stream and riparian habitat and social functions. A workshop was held in 2010 in Ballater, UK to highlight research on riparian buffer strips brought together under the EU COST Action 869 knowledge exchange programme.
Following this workshop the James Hutton Institute has contributed to six out of thirteen papers for a special collection of the Journal of Environmental Quality, and acted as editor with colleagues at the Danish National Environmental Research Institute and at Alterra Institute in the Netherlands. The link to access the summary paper from this special collection is given here.
What does the research tell us?
Given design consideration and some limited ongoing maintenance riparian buffer strips can provide multiple benefits to compensate for the small amount of land taken out of production, such as a physical barrier between spraying and fertilising activities and the stream, trapping sediment and nutrient runoff from fields, allowing trees to grow which stabilise banks from eroding via root growth, provide habitat and shade waters from extremes of temperatures that kill fish, and by providing access to walk alongside streams and rivers.
To ease the legislative process buffer strips are often narrow mandatory strips uniformly against all streams and rivers, across different riparian soil water conditions, between bordering land uses of differing pollution burdens and without prescribed buffer management. It would be easy to criticise such regulations for not providing the opportunity for riparian ecosystems to maximise their provision of a wider range of ecosystem goods and services. However, the scientific basis on which to judge the best course of action in designing and placing buffers to benefit their multifunctionality has slowly increased over the last 5 years. Our collection of papers evaluates a range of studies of riparian buffer management and assessment from across Europe. The themes addressed are: (i) evidence of catchment- to national- scale effectiveness, (ii) ecological functioning linking terrestrial and aquatic habitats, (iii) modelling tools for assessment of effectiveness and costs, and (iv) process understanding enabling management and manipulation to enhance pollutant retention in buffers. The combined understanding leads us to consider four principle key challenges for buffer strip research and policy:
- How can we bring efficient placement and design of buffers in landscapes to minimise diffuse pollution delivery?
- What are the key aspects and aims in the ongoing management of riparian buffers?
- How can we maximise benefits for riparian habitat restoration through buffer design?
- What are the most important aspects of multiple benefits to different stakeholders and how should we go about observing progress to achieving desired goals?
For more information contact: Marc Stutter