Assessment of mycorrhizal colonisation and soil nutrients in unmanaged fire-impacted soils from two target restoration sites

摘要

The mycorrhizal colonisation of plants grown in unmanaged soils from two restoration sites with a fire history inNorthern Portugal was evaluated from the perspective of supporting restoration programmes. To promote restorationof original tree stands, Quercus ilex L. and Pinus pinaster Ait. were used as target species on two sites, denoted Site1 and 2 respectively. The aim of the study was to assess whether mycorrhizal propagules that survived fire episodescould serve as in situ inoculum sources, and to analyse the spatial distribution of soil nutrients and mycorrhizalparameters. In a laboratory bioassay, P. pinaster and Q. ilex seedlings were grown on soils from the target sites androot colonisation by ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi was determined. The ECM rootcolonisation levels found indicated that soil from Site 2 contained sufficient ECM propagules to serve as a primarysource of inoculum for P. pinaster. The low levels of ECM and AM colonisation obtained on the roots of plants grownin soil from Site 1 indicated that the existing mycorrhizal propagules might be insufficient for effective root colonisationof Q. ilex. Different ECM morphotypes were found in plants grown in soil from the two sites. At Site 2 mycorrhizalparameters were found to be spatially structured, with signif icant differences in ECM colonisation and soil Pconcentrations between regions of either side of an existing watercourse. The spatial distribution of mycorrhizalpropagules was related to edaphic parameters (total C and extractable P), and correlations between soil nutrients andmycorrhizal parameters were found.