Hydrological responses to managed burning and grazing in an upland blanket bog

摘要

The management of the UK uplands by rotational burning and grazing is a widespread practice that aims to control the development of vegetation in order to create suitable habitats for grouse and sheep. By modifying the above ground biomass it is possible that above and/or below ground hydrological regimes may be altered. This study investigates the effect burning has on various hydrological parameters of an upland blanket bog. The study was conducted on a long-term experimental site examining different combinations of managed burning and grazing intensities. The study has found that: (1) Although depth to water table shows strong seasonal trends, the shallowest water tables were found on those sites that were burnt every 20 years and grazed by sheep. The deepest water tables were found on those sites that had never been burnt. (2) In the year following a managed burn, water tables on those sites that were burnt were significantly shallower than before the burnt. (3) Hydraulic conductivity, as determined by dipwell slug tests, was found to be significantly lower on those plots that were burnt every 20 years. (4) Runoff occurrence was recorded and occurred at a significantly greater frequency on those sites that had recently been burnt. (5) By using antecedent weather conditions, significant parameters were found that could be used to model runoff generation. This paper demonstrates how the use of managed burning in upland settings can affect various hydrological responses of the peatland. These variations in hydrological response will have important consequences on DOC export through changes in water table and the partitioning of precipitation into runoff.