Soil properties rather than topography, climatic conditions, and vegetation type shape AMF-feathergrass relationship in semi-natural European grasslands

Due to the fact that arbuscular mycorrhizal fungi (AMF) provide water and elements (e.g. phosphorus) to the host, arbuscular mycorrhiza (AM) is considered to be an important plant-fungi interaction and can be helpful for plants occupying extreme habitats. Such habitats include Central European semi-natural dry feathergrass grasslands. One of the main components of feathergrass steppes in Eurasia is Stipa pennata (Poaceae). Currently, because of a lack of land use leading to the overgrowth of grasslands and consequently to habitat deterioration, this species is rare and protected in many European countries. No information regarding the simultaneous impact of vegetation, topography, soil and climatic factors on the AMF-feathergrass relationship has been published to date. Thus, the aim of our study was to investigate factors that shape AMF root colonisation and AMF community composition in different types of European semi-natural feathergrass niches occupied by S. pennata. To do that, we collected roots and soil samples along with data about topography, soil chemical and physical properties, climate and vegetation cover from three different types of edaphic niches. We found that AMF root colonisation was lower in sand than in gypsum or limestone soils and was largely explained by environmental factors. AMF root colonisation degree was predominantly influenced by soil nitrogen content, and increased along with pH. Soil physical stress disrupted relationships between AMF root colonisation degree and soil pH. The largest percentage of variance in the composition of AMF communities was explained by soil factors, followed by climate, topography and vegetation. AMF communities associated with S. pennata were composed mainly of 'generalists' species.