Research Article |
Corresponding author: Filippo Prosser ( prosserfilippo@fondazionemcr.it ) Academic editor: Lorenzo Peruzzi
© 2023 Filippo Prosser, Alessio Bertolli, Giulia Tomasi.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Prosser F, Bertolli A, Tomasi G (2023) Changes in the flora of Lobbia Alta, a peak of the Adamello-Presanella Alps (Trento, Italy) between 1935 and 2021. Italian Botanist 15: 9-20. https://doi.org/10.3897/italianbotanist.15.97630
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Global warming is causing an enrichment of summit flora worldwide. This article presents the case of a peak in the southeastern Alps (Lobbia Alta, 3,196 m a.s.l., Adamello, Trento, Italy), for which a complete list of tracheophytes dating back to 1935 was available. As this peak is well delimited by glaciers and vertical cliffs, it has been possible to faithfully repeat this floristic inventory. We made three surveys, in 1991, 2006 and 2021, exploring the whole area. It resulted that in 86 years the species present on this peak have tripled, increasing from 17 to 51, with an acceleration in recent years. The biological forms have increased from two to six. The average temperature and the nutritional indexes according to Ellenberg have increased as well. We found that as many as six species reach their elevation record in the Alps on the Lobbia Alta, suggesting that this area is particularly prone to species ascension. Particularly interesting is the discovery of a 35 cm-tall specimen of Larix decidua at 3,130 m a.s.l., which seems to be the elevational record of the species.
Climate change, flora of Trentino, southeastern Alps, summit flora
In the Alps, the climate has warmed by about 1.8 °C since 1880, almost double the global average. Models are especially pessimistic for the southern Alps, where at the end of the current century an increase of more than 4 °C compared to the period 1981–2010 is expected in a worst-case scenario (
The aim of this research was to investigate the changes in the summit flora of a peak on the southern slope of the eastern Alps, an area particularly prone to global warming. We also sought to establish whether the plants found there constituted an elevational record.
The Lobbia Alta (3,196 m a.s.l.; 46.1704°N, 10.5674°E; Fig.
Nino Arietti (Bardolino 1902; Brescia 1979), one of the most important botanists in Brescia, noticed that the Lobbia Alta corresponded to what botanists at the time called the “glacial island” and for this reason, in 1935, he surveyed its flora (
The herbarium of Nino Arietti, kept at the Civic Museum of Natural Sciences of Brescia (HBBS,
In all of our three surveys (1991, 2006 and 2021), the entire area (Fig.
The sampling effort of our surveys was as follows: on 25 August 1991, Lobbia Alta was visited by one of the authors of this paper (FP) and three operators; we estimate that the survey took about 6 hours. On 23 August 2006 it was investigated by two of the authors of this paper (AB and FP) and five operators (
Biological forms follow
The number of species surveyed on Lobbia Alta in 86 years has risen from 17 to 55 (Suppl. material
Variability of the temperature index and nutrients index for each survey are shown in Figs
In the period 1935–1991, the number of species grew from 17 to 36 (Suppl. material
In the period 1991–2006, the number of species rose to 45 with the confirmation of all the species surveyed in 1991 (Suppl. material
In the period 2006–2021, the total number of species rose to 51, with an entry rate of 0.4 species / year. As many as 10 species were found for the first time; however, compared to 2006, four species are not confirmed (Potentilla frigida Vill., Rhododendron ferrugineum, Salix herbacea and Solidago virgaurea subsp. minuta (L.) Arcang.). The first phanerophyte, Larix decidua Mill., and the first geophytes, Agrostis schraderiana Bech. and Coeloglossum viride (L.) Hartm., appear. Among the nanophanerophytes, R. ferrugineum is not confirmed, but Salix helvetica Vill. appears. Furthermore, among the fruticose chamaephytes, the lack of confirmation of S. herbacea is compensated by the addition of Empetrum hermaphroditum Hagerup. The temperature index approaches 2 (Fig.
The elevations recorded in the 2021 survey show that for about 20 species the elevation record published in “Flora del Trentino” had been exceeded (
Coeloglossum viride, a circumboreal species present at 3,150 m a.s.l. on the Lobbia Alta, is probably the highest known orchid in Europe, including the Caucasus (
Gentiana nivalis L., a species widespread mainly in the European mountains, was found at 3,123 m on the Lobbia Alta, just above the known elevations in the Alps. The second known record is 3,110 m in Val di Cogne in the Pousset valley (2001, Poggio and Gerard in
Gentianella anisodonta (Borbás) Á.Löve & D.Löve, an endemic species to the eastern Alps, found at 3,145 m on the Lobbia Alta, is most likely the record for the elevation of the species.
We found a 35-cm tall specimen of Larix decidua on Lobbia Alta (Fig.
Primula daonensis, an endemic species to a small sector of the eastern Alps, was found up to 3,151 m on the Lobbia Alta; it confirms an earlier record for the species, which was always on the Lobbia Alta at 3,110 m (
Salix helvetica, a species with alpine distribution, was found at 3,111 m on the Lobbia Alta, but the specimen is little more than a seedling. The second highest record is at 3,010 m in Val di Cogne, under the Lauson glacier (Mainetti et al. 2016 in
Our results are in agreement with the general trend of enrichment of the flora of the high alpine peaks. Various species have managed to reach the Lobbia Alta, despite being a rather isolated peak surrounded by ice and inhospitable cliffs. Seed dispersal by wind (e.g., Larix decidua) and birds (e.g., Empetrum hermaphroditum) has made it possible to colonize these peaks. More and more often, seedlings and saplings find suitable conditions for their establishment due to the increasingly longer period without snow, consequent to climate warming. Lobbia Alta, and in particular its southern side, appears suitable for the settlement of species from lower elevations, as shown by elevation records also for some species that are widespread in the western Alps (Gentiana nivalis, Larix decidua, Salix helvetica) where, due to the mass effect, species usually reach their highest elevation in the Alps (see e.g.,
In 2021, the presence of some species, recorded after 1935, has not been confirmed, i.e., Potentilla frigida, Rhododendron ferrugineum, Salix herbacea, and Solidago virgaurea subsp. minuta; this would suggest that the colonization process is not linear, but is “trial and error”. On a peak of more than 3,000 m a.s.l. such as Lobbia Alta, it is the newcomers who are more likely to disappear, rather than the species that have been established there since a long time. Nonetheless, the latter could also be undermined by further global warming.
We thank Gilles André, Elena Barni, Enzo Bona, Jasmin Ducry, Khatuna Gigauri, Michael Jutzi, Harald Pauli, Jean-Louis Polidori, Jean-Paul Theurillat, Thomas Wilhalm, Sonja Wipf for providing data on elevation records of species; Luca Bronzini, Sara Tamanini and Massimo Tambosi for the help offered during the survey of 1991; Elena Guella, Maurizio Odasso, Lucio Sottovia, Mauro Tomasi and Luca Bronzini again for the help offered during the survey of 2006. Finally, we thank the anonymous reviewers who contributed to greatly improve the text.
Floristic occurrences of the flora of the Lobbia Alta (Trento, Italy) between 1935 and 2021
Data type: table (excel file)