Conservation status assessments cited here follow the IUCN Red List categories and criteria (version 3.1) and the Italian National Red List for vascular plants (2020). Regional assessments may differ from national figures. This article reflects data available as of May 2026; any subsequent revisions to official assessments should be verified against primary sources.
Overview of Threat Status in Italian Thistle Flora
Of the approximately 45 Cirsium, Carduus, and Onopordum taxa recorded from Italy (including subspecies recognised in the most recent national checklist), at least 11 carry some form of national or regional threat designation. The highest concentration of threatened taxa occurs within the genus Cirsium, which includes several narrow endemics restricted to specific Apennine sub-ranges or to coastal habitats under acute pressure from tourism and infrastructure development.
The 2020 Italian National Red List assessed 113 Asteraceae species at national level. Among the tribe Cardueae (which includes all three thistle genera covered here), the proportion assessed as Threatened (Vulnerable, Endangered, or Critically Endangered) is markedly higher than for Asteraceae as a whole, reflecting the dependence of many thistles on semi-natural grassland habitats that have contracted by an estimated 40–60% in Italy since 1960.
Critically Endangered and Endangered Species
Cirsium tenoreanum Pett. — Tenore's Thistle
Restricted to a small number of known localities in the Basilicata and northern Calabria Apennines, all below 1,400 m. A perennial with narrow, deeply divided leaves and relatively small pale purple heads (2–3 cm). The total known population was estimated at fewer than 500 mature individuals in the most recent dedicated survey (2018, Italian Ministry of Environment). Primary threats are overgrazing by feral cattle in the Pollino National Park buffer zone, where the largest subpopulation occurs, and scrub encroachment on previously managed hay meadows following abandonment of traditional agro-pastoral practices. Status: Endangered (EN) — Italian National Red List 2020.
Cirsium apenninum (Ten.) Grande — Apennine Thistle
A Tyrrhenian-slope endemic distributed across four discrete range fragments in the central and southern Apennines. Perennial, 50–100 cm, with pinnately lobed grey-green leaves and nodding flower heads 3–4 cm, pale pink. Documented from moist rocky grassland and stream margins between 800 and 1,600 m. The main subpopulation in the Monti Lattari (Campania) faces pressure from tourist track construction and trampling. Status: Endangered (EN) — Italian National Red List 2020.
Vulnerable Species
Cirsium italicum (Savi) DC. — Italian Thistle
Assessed as Near Threatened at national level and as Vulnerable in the regional red lists of Tuscany and Emilia-Romagna. Total range is disjunct across the central and southern Apennines and isolated coastal sites in Le Marche and Abruzzo. The primary pressure is mesophilous scrub encroachment following cessation of annual hay cutting, which removes the light conditions necessary for regeneration from seed. Road verge management is a secondary threat; C. italicum colonises road embankments where cutting is timed appropriately but is eliminated where verges are cut before seed set (i.e., before late August).
Cirsium morisianum Rchb. f. — Moris's Thistle
A Sardinian endemic, the sole representative of the island's endemic thistle flora at the species level. Restricted to granite grasslands and rocky scrub edges in the Gennargentu massif and Sulcis-Iglesiente mountains, 400–1,200 m. A robust perennial to 1.5 m with large (5–8 cm) dark purple flower heads. The Sardinian regional assessment places it as Vulnerable; total known occupied area is estimated below 200 km². Fire regime changes and increased recreational use of the Gennargentu National Park represent the main current pressures. Status: Vulnerable (VU) — Sardinian Regional Red List.
Carduus chrysacanthus Ten. — Golden-Spined Thistle
Notable for its golden-yellow spine tips, a character unique among Italian Carduus. Restricted to dry limestone grassland and garigue in Campania, Calabria, and Sicily, below 800 m. The species is sparse throughout its range and has not been the subject of a detailed population census since 2012. Agricultural intensification on the Campanian plain has reduced lowland populations; Sicilian records are concentrated in the Madonie and Nebrodi parks. Status: Vulnerable (VU) — Italian National Red List 2020.
Habitat Pressures: What Is Driving Decline
Field surveys and literature synthesis identify four dominant pressure types across threatened Italian thistle populations:
1. Agricultural Intensification and Herbicide Use
Herbicide application along field margins and roadsides is the single most cited pressure in conservation assessments for lowland Carduus and Cirsium species. In the Po Valley, broad-spectrum herbicide applications to cereal field margins have effectively eliminated Carduus acanthoides and C. arvense from large sections of the agricultural plain, though both remain common where margins are unsprayed. For the rarer C. italicum, even low-frequency applications of aminopyralid-based herbicides can suppress flowering without complete plant mortality.
2. Scrub Encroachment Following Land Abandonment
Rural depopulation in the Apennines since the 1960s has resulted in widespread abandonment of traditional hay meadows and extensively grazed grasslands. Without regular cutting or grazing, tall scrub — primarily Prunus spinosa, Crataegus monogyna, and Rosa canina — colonises meadow margins within 5–10 years, shading out the biennial and perennial thistles that require relatively open, low-competition conditions for establishment.
3. Alteration of Grazing Regimes
While overgrazing can eliminate sensitive thistle species from pastures, the more widespread problem in the Italian Apennines is under-grazing or complete grazing withdrawal. Several Cirsium endemics depend on grazing disturbance to maintain the open microsites required for seedling establishment. The shift from extensive cattle and sheep grazing to fallow pasture in mountain areas has been documented as a contributing factor in the decline of C. tenoreanum and C. apenninum at multiple sites.
4. Coastal Development
For thistle species with coastal or sub-coastal distributions (notably some Carduus taxa in Sicily and Sardinia), beach stabilisation works, road construction, and tourism infrastructure have directly destroyed known localities. Coastal dune habitats supporting Carduus pycnocephalus aggregations on the Tyrrhenian coast have contracted by an estimated 35% between 2000 and 2020 according to ISPRA habitat mapping data.
Protected Areas and Existing Safeguards
All Italian Critically Endangered and Endangered thistle taxa have at least one known subpopulation within the national park system or within a Natura 2000 Special Area of Conservation. The Pollino National Park (Basilicata/Calabria), the Cilento and Vallo di Diano National Park (Campania), and the Gennargentu National Park (Sardinia) collectively encompass the largest proportion of known threatened thistle populations. However, protected area designation does not automatically translate into habitat management: several Apennine parks lack the resources to maintain the hay-cutting regimes or controlled grazing that are required to prevent scrub encroachment.
The Italian agri-environment scheme under the Common Agricultural Policy (CAP) Pillar 2 includes a "semi-natural grassland maintenance" measure that provides payments to farmers maintaining traditional late-cut meadows. Uptake in areas with threatened Cirsium populations has been assessed as moderate; the Italian Institute for Environmental Protection and Research (ISPRA) identified insufficient targeting of the measure toward localities with documented rare species as a weakness of the 2014–2020 programming period.
Data Gaps and Research Priorities
Several aspects of Italian thistle conservation biology remain poorly documented:
- Population size and trend estimates for C. tenoreanum and C. apenninum require updated field surveys; both species were last systematically counted before 2020.
- Seed bank longevity data for Apennine endemics are absent; this affects the feasibility assessment of ex situ conservation measures.
- The impact of climate change on phenology and altitudinal range is not yet modelled for Italian Cirsium endemics; upslope range shifts have been hypothesised based on European-scale analyses but not directly measured in Italy.
- Genetic diversity assessments using microsatellite markers are available for C. vulgare and C. arvense across Europe but have not been conducted for any Italian endemic taxon.
External Assessment Sources
- IUCN Red List: iucnredlist.org
- Italian National Red List for Vascular Plants (2020): ISPRA
- GBIF species occurrence data: gbif.org
- Plants of the World Online (taxonomy and distribution): powo.science.kew.org