IUCN assessments classify two Italian metallophytes and one Uzbek endemic as Endangered

Four plant taxa were assessed for the IUCN Red List in regional and global evaluations: two metal-tolerant plants in northeastern Italy and two endemic plants from Uzbekistan’s Nuratau Mountains. The regional assessments classified Alyssum wulfenianum subsp. wulfenianum and Noccaea cepaeifolia as Endangered in Italy. At the global level, Phlomoides anisochila was classified as Endangered, while Phlomis nubilans was classified as Near Threatened.

These Red List assessments were based on compiled occurrence records, field observations, population estimates, information on ecology and reproduction, and geospatial calculations. The two Italian taxa were evaluated under criterion B using an extent of occurrence calculated with a minimum convex hull in QGIS 3.28.13 and an area of occupancy calculated with a fixed grid of 2 × 2 km cells. The two Uzbek taxa were evaluated with GeoCAT using the same grid dimensions.

For Alyssum wulfenianum subsp. wulfenianum, the Italian regional assessment estimated an extent of occurrence of 60.2 km² and an area of occupancy of 20 km². The regional population was estimated at about 3,600 mature individuals. This narrow endemic is restricted to the southeastern limestone Alps, principally around Cave del Predil and the Rio del Lago valley in Friuli-Venezia Giulia, with a smaller distribution across the border in Carinthia, Austria.

The subspecies is a perennial that grows on calcareous rocks, screes, debris, and gravel-sand riverbeds at approximately 600–900 m above sea level. It is described as a hyperaccumulator metallophyte associated with high concentrations of zinc and lead and is also reported to accumulate thallium. It occurs where natural contamination or mining has created metal-rich substrates and is considered a poor competitor on non-metalliferous soils. Subpopulations on the slopes of Mount Re were described as stable, whereas those in the Rio del Lago stream bed were highly fluctuating and in decline.

The assessment classified A. wulfenianum subsp. wulfenianum as Endangered under criteria B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v), reflecting no more than five locations and continuing declines in area of occupancy, habitat extent and quality, locations or subpopulations, and mature individuals. Potential future changes associated with mine remediation, hydrological regulation, gravel extraction, and phytoremediation were distinguished from the observed condition of the populations. Increased recreational use of the Cave del Predil geomineral park and resulting human trampling were also identified as threats. No information on extreme fluctuations was available for this assessment.

For Noccaea cepaeifolia, the Italian assessment estimated an extent of occurrence of 21.5 km² and an area of occupancy of 16 km². Its Italian population was described as a few thousand individuals, with additional small, scattered subpopulations. The narrow endemic occurs in the calcareous southeastern Alps, with its Italian range centered on Cave del Predil and a limited extension into Carinthia. Some subpopulations in former mining areas and on nearby slopes were considered stable, but reductions had been observed in lower-altitude populations along Rio del Lago.

N. cepaeifolia was also classified as Endangered in Italy under criteria B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v). As with A. wulfenianum subsp. wulfenianum, the assessment cited no more than five locations, continuing declines in geographic and demographic measures, potential habitat alteration from mining remediation and riverbed works, and trampling associated with recreation. The assessment did not report information on extreme fluctuations. Both Italian assessments noted that detailed reproductive information was unavailable, and the authors called for research and monitoring of reproductive biology, environmental influences on reproduction, population trends, and the effects of mining remediation and flooding.

The global assessment of Phlomis nubilans estimated 50,000–100,000 mature individuals from field studies conducted over the preceding 10 years, alongside 71 known occurrence records. Its calculated extent of occurrence was 4,381.61 km² and its area of occupancy was 172 km². The endemic perennial occurs in the Nuratau Mountains, where agricultural development, excessive grazing, geological exploration, mining, and quarrying were identified as pressures. Grazing was described as the main indirect threat because livestock trample young plants and contribute to soil erosion and habitat degradation, although livestock do not eat the species.

Although P. nubilans met the numerical area thresholds associated with criterion B for Endangered, the assessment cited more than 10 locations, more than 10,000 mature individuals, no severe fragmentation, and no known extreme fluctuations. It was therefore classified as Near Threatened. A species-distribution model projected a significant reduction in suitable range under the RCP8.5 scenario as aridification increased; this was a model-based projection rather than an observed loss of area. The demographic structure of the species was described as poorly studied, with available data regarded as contradictory.

Phlomoides anisochila was classified as Endangered globally under criteria B1bc(ii,iii,iv)+B2bc(ii,iii,iv)+C2ab. Field work documented about 1,000 individuals across 34 occurrence records, with small isolated groups commonly containing 10–30, 50–70, or occasionally 100–200 plants. Its extent of occurrence was 214.5 km² and its area of occupancy was 40 km². The assessment recorded extreme fluctuations in mature individuals and estimated fewer than 250 mature plants in the largest subpopulation, supporting the application of criterion C as well as criterion B. Grazing, geological exploration, avalanches, mudflows, and drought-related pressures were identified, while species-distribution modeling projected a reduction in suitable range under the RCP8.5 scenario as drought increased. The authors proposed expanded protection within Nuratau Nature Reserve, regulation of grazing, restrictions on mining and geological exploration, research and monitoring, cultivation methods, reintroduction, and seed banking for the two Uzbek taxa.

Subject of Research: Regional and global IUCN Red List assessments of four threatened plant taxa in Italy and Uzbekistan

Article Title: Global and Regional IUCN Red List Assessments: 18

Article References: Orsenigo, S., Beshko, N. Y., Casolo, V., Castello, M., Khabibullaev, B. S., Petrussa, E., Shomurodov, K. F., Uliana, L. R., & Fenu, G. (2025). Global and Regional IUCN Red List Assessments: 18. Italian Botanist, 19, 185-203. https://doi.org/10.3897/italianbotanist.19.156865

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.19.156865

Keywords: IUCN Red List, plant conservation, Italy, Uzbekistan, metallophytes, Nuratau Mountains, Cave del Predil, endemic plants, habitat degradation, population monitoring, Global, Regional