Spatial distribution of soil ergosterol in the organic layer of a mature Scots pine (Pinus sylvestris L.) forest

The spatial structure of the organic layer fungal biomass estimated from so il ergosterol content of a 1 ha plot in a mature Scots pine (Pinus sylvestr is L.) forest was described from 181 samples and examined in relation to th e organic layer properties (thickness, pH, total C, N, K, Mg and Ca) and tw o above-ground environmental factors: gap fraction, i.e. proportion of sky not shaded by trees directly above the sampling point and throughfall. Ergo sterol content of the organic layer had a clear spatial dependence over the studied area, and the spatially structured autocorrelation variance accoun ted for up to 90% of total sample variance in a 4 m range. Most of the meas ured properties of the organic layer and the above ground environmental fac tors were also spatially dependent, although to varying degrees. The spatia l pattern of ergosterol was most strongly related to pH, organic layer thic kness and total C content. Our analyses did not show any direct influence o f gap fraction and throughfall on ergosterol. However, gap fraction and thr oughfall were related to organic layer thickness indicating the importance of the associated factors (moisture, light, temperature, quality of litter) on forest litter decomposition. (C) 1999 Elsevier Science Ltd. All rights reserved.