| Summary: | The Uplands are very distinctive environments for their habitats, wildlife, land use, and management history. They mostly support heather communities and organic soils; their functioning is intrinsically linked to management practices (heather burning, draining and grazing). Recent habitat losses in the uplands have shown a need for their protection. This study focuses on the consequences of heather burning on peat soil characteristics in the Pennines. Two areas of research were investigated: (1) the modifications of the organic matter characteristics and input of black carbon (BC) to soil as a result of heather burning, and (2) the potential alteration of the soil accumulation rate due to fire regimes. The use of 13C NMR spectroscopy of soil organic matter has shown none of the structural changes usually observed for vegetation and soil affected by fire (e.g. increase of aromatic C), possibly indicating insufficient number of successive fires for changes to be noticeable. Instead, the changes were related to the degree of soil decomposition. A laboratory controlled burning experiment estimated low charcoal production from heather «1% vegetation biomass), representing a potentially low input of aromatic C and BC in soils. BC analyses of soil samples did not show any direct increase of BC content in soil either immediately after the fire, or at longer fire rotations (i.e. every 10 and 20 years). Rather, the BC content in soils is thought to originate from fossil fuel combustion. Dating techniques e1oPb), chronological indicators (total Pb, stable isotopes), and their comparison with external references to assess the soil accumulation rate indicate possible overestimations of the values. In this particular context, the validity of the 210Pb technique is questioned. The alteration of the signal in soils could be due to a volatilisation and redeposition of 210Pb during the fire. This needs further investigation.
|
|---|
