Pedo-climatic and land use preferences of Gentiana lutea subsp lutea in central Italy

Background and aims - Gentiana lutea L. is a species of high economic importance threatened in several European countries and included in their Red lists. Nevertheless, there is a dearth of data about its ecology, especially in the Mediterranean mountains, which are the southern part of its distribution area. Our aim was to determine the environmental constraints affecting the distribution and performance of G. lutea in the aforesaid context. Methods - We performed the research on the Sibillini Mountains (central Italy) by assessing the relations between some vegetative traits and types of land use. Using a stratified sampling design, we randomly selected a number of 500 x 500 m cells including one or more populations. Our sampling scheme was based on two different grain sizes: 10 x 10 m plots and individuals level. Data were analysed using descriptive statistics, Mann-Whitney U-test, and Redundancy Analysis. Key results - G. lutea was found on northerly slopes with moderate slope angle, mostly at altitudes ranging from 1450 to 1750 m a.s.l., shifting on southerly aspects at the highest altitudes. Available Water Capacity was the main variable leading the vegetative performances of individuals (optimal values were greater than 50). The relatively low values of soil water deficit (mostly lower than 30 mm yr(-1)) indicated a very low tolerance of the species to summer water stress. Grassland abandonment was the most suitable land use for the spread of G. lutea populations. Conclusion This study addressed the dearth of data on the ecology of G. lutea providing more information about the main environmental factors affecting its spatial pattern of distribution in central Apennine, providing key data for assessing the land suitability for G. lutea cultivation.