| Abstract: | Gentiana lutea L. subsp lutea (hereafter G. lutea) is a long-lived geophyte, which has high
medicinal value for the intensely bitter properties residing mainly in the root, being the main
vegetable bitter employed in homeopathy and for the liqueurs production. G. lutea is presented in
the Annex V of the Directive 92/43/EEC. In addition, it’s included in the List of endangered
medicinal plants in the Annex D to the Council Regulation (EC) No. 338/97 of EU, whose purpose
is the protection of plant species by control of their trade.
Due to a lack of knowledge on the current G. lutea distributional information in Sardinia,
Species Distribution Models (SDMs) could be even an important tool to limit search efforts by
selecting the areas where field surveys are to be carried out for guiding discoveries of new localities
and to evaluate the influence of extant and extinct localities. Once distribution knowledge was
updated, further activities performed on representative localities, including ex situ and in situ
studies were carried out.
Firstly, our contribution to conserve this specie in Sardinia, included ex situ aspects that
provided an alternative and complementary method for preventing immediate extinction and
support further interventions. The experimental examination of the time when germination occurs in
natural sites, the understanding of the seed behaviour in the soil and the investigation of the
germination response under laboratory conditions. In particular, the isolated and on the boundary
Sardinian population can differ genetically and morphologically from central populations because
of their smaller population size and greater physical and ecological distances from the centre of the
range, and may contain genotypes adapted to extreme environmental conditions; it is therefore
important to check the effect on seed ecophysiology germination on small and spatial isolated
populations. Previous studies have found that the germination of many mountain plants was
promoted by cycles of cold-wet stratification that released seed dormancy in transient and
permanent seed banks. In this way, dormancy played a key role in optimizing germination success
by controlling the timing of germination. Thus, this research would contributed to this species
conservation, suggesting the optimal protocol of germination and multiplication and, on the other
hand, the information of the different kinds of seed dormancy.
G. lutea is reported as being threatened not only by root harvesting practices, but also by
global climatic warming due to its distribution, which is restricted mainly to the upper sectors of the
mountains. Especially in mountain areas, climate warming is projected to shift species’ ranges to
higher elevations. Plant species have responded to global warming through a generally accelerated
phenology, enhanced growth and increased reproductive effort. Even fewer studies have addressed
such response of the populations at the boundary of species range distributions which are thought to
be particularly sensitive to climate change, hence it was evaluated the effect of anomalous
temperatures (extremely warm) during the year of 2015 on phenology and reproductive successful.
Monitoring the underlying drivers of this variation in phenological shifts will contribute to a
mechanistic understanding of the biological effects of climate change.
Finally, the criteria established by the IUCN that are widely employed as the gold standard
for information on the conservation status of species were applied at regional scale for G. lutea. The
assessment through the IUCN Criteria and Categories at global level was updated as Least Concern
(LC) and at Italian level as Near Threatened (NT). Considering the regional level, the only previous
assessment in Sardinia date to back to 1997 as Critically Endangered (CR), this work will contribute
to an implementation of knowledge and conservation management for this taxon. An updating of
local conservation status of G. lutea was thus provided by the analysis of its decline and comparing
its potential suitable habitats based on the emissions scenarios presented by the Intergovernmental
Panel on Climate Change (IPCC) for 2050 and 2070. |
