Lichens from the aurifodinae of the upper Ticino river valley (N Italy)

Aurifodinae were open-pit gold mines of the Roman age which left behind them elongated heaps of rounded stones. They are located in lowland semi-natural landscapes, and can be seen as screes at a lower altitude and in a milder climate than typical mountain screes. We investigated the lichen biota of the aurifodinae remains in the upper Ticino river valley (western Po Plain, Northern Italy), in a small, discontinuous, 6.5 ha wide area. Metamorphic siliceous stones prevail, while calcareous stones are rare and scattered. We recorded 35 infrageneric taxa, including three species new to Piemonte: Cladonia conista, C. cryptochlorophaea, and Placidiopsis cinerascens. Several taxa are also new to the submediterranean ecoregion and/or to the Ticino river valley. The function of aurifodinae as a refugium for saxicolous lichens in the lowlands and their potential role in creating wide areas with open dry habitats in the past centuries are discussed.