The reliability of conservation status assessments at regional level: Past, present and future perspectives on Gentiana lutea L. ssp. lutea in Sardinia

Regional assessments could be more reliable than global ones, especially for species in peripheral parts of their range. In this sense, distribution criteria proposed by the IUCN, expressed by the Extent of Occurrence (EOO) and the Area of Occupancy (AOO), are of critical importance to evaluate the risk category at any scale. Our study was focused on the yellow gentian (Gentiana lutea L. subsp. lutea), a rhizomatous mountain plant of central and southern Europe, included in the Annex V of the Directive 92/43/EEC. The exhaustive and updated regional distribution and the recently published extinct localities, allowed for review of option to increase the number of criteria used for its regional conservation status assessment. In particular, the current restricted EOO and AOO extents and reductions occurred during the last three generations led this plant being considered as Endangered (EN), according to the IUCN sub-criteria A2, B1 and B2. Additionally, Species Distribution Models based on the extant localities and the respective current and future climate scenarios (2050 and 2070) predicted a decrease of its environmental niche reducing its altitudinal range towards higher elevations. This reduction was greater than 50% and confirmed the regional conservation status of EN, also according to the sub-criterion A3.This paper shows the reliability of regional risk assessment of peripheral and/or narrow populations, which is an effective tool for helping the development of the necessary conservation management, underling a diversified set of solutions for each specific past, present and future threat that could occur in each locality.