Five Rare Plants Join the IUCN Red List as Global Assessments Reveal Rising Extinction Risk

Deep in the foothills of the northern Tian-Shan, a bulbous iris with greenish-yellow flowers pushes through gravelly serozem soils each March, one of the first plants to bloom as the Central Asian spring arrives. In the Nuratau Range of Uzbekistan, a perennial relative of cress clings to just three mountain valleys, its rhizomes dug up by locals to treat digestive ailments and to brace the legs of racehorses used in traditional equestrian games. On a windswept plateau 3,000 meters above sea level, a cushion-forming mustard no taller than ten centimeters survives in a zone where the mean annual temperature hovers around freezing. On the dunes of Sardinia, an annual grass flickers in and out of existence depending on the year’s rainfall, sometimes reaching more than twenty plants per square meter and sometimes nearly vanishing. And on the granite outcrops of the Ulytau massif in central Kazakhstan, a tansy with no plume on its seeds sits stranded on tiny rocky islands within a sea of steppe. What unites these five plants is a new label: Endangered, according to the International Union for Conservation of Nature.

The assessments, published in the journal Italian Botanist as part of an ongoing series of global and regional Red List evaluations, formally classify Iris kuschakewiczii, Lepidium olgae, Parrya saxifraga, Phleum sardoum and Tanacetum ulutavicum as Endangered at the global level. None of the five had ever been assessed before at the global scale, a sobering reminder of how many of the world’s plants remain invisible to conservation planning simply because nobody has yet counted them. The IUCN system is deliberately quantitative: species are assigned to categories based on measurable thresholds, such as the extent of their occurrence, the area they actually occupy, population size, fragmentation and documented decline. Each of these five species crossed those thresholds on multiple independent criteria, and the detailed rationales behind the listings reveal common threads that run far beyond any single plant or country.

Iris kuschakewiczii, known in English as Kuschakewicz’s iris, is a narrow endemic of the mountains of Central Asia biodiversity hotspot, found in south-eastern Kazakhstan and adjacent northern Kyrgyzstan at elevations of roughly 400 to 1,100 meters. It is an early-spring geophyte, a bulb-plant strategy shared with its relatives in subgenus Scorpiris, flowering in March and April and fruiting by May. Expert assessment places the global population at between 6,000 and 18,000 mature individuals, a seemingly healthy number until one examines how those plants are distributed. Field studies recorded densities ranging from 0.6 to 8.8 individuals per square meter in some areas, and an extraordinary 5.5 to 46.7 individuals per square meter in the Chu-Ili Mountains, where populations above 900 meters show complete ontogenetic spectra, meaning all life stages are present and recruitment is active. Yet other populations have been reduced to only a few flowering plants by chronic overgrazing during precisely the weeks when the species flowers and sets seed.

The iris earned its Endangered listing under criterion B2ab(iii,v), a technical shorthand worth unpacking because it explains exactly what the data show. Its area of occupancy, calculated with the GeoCAT tool using two-kilometer grid cells, is just 312 square kilometers, even though its overall extent of occurrence spans 57,592 square kilometers. The species is severely fragmented, confined as it is to discontinuous rocky and gravelly habitat patches separated by plains, agricultural land, settlements and overgrazed foothills. Its seeds are dispersed primarily by barochory, meaning they simply fall to the ground, and no long-distance dispersal mechanism is known. Once a population is extirpated, recolonization is therefore unlikely. Continuing decline is documented in both habitat quality and the number of mature individuals, driven by nomadic and small-holder grazing, quarrying, road construction and the steady expansion of settlements into the lower foothills. The species is already listed in the Red Data Book of Kazakhstan, but most of its populations lie outside formally protected areas.

Even more precarious is the situation of Lepidium olgae, a perennial herb endemic to the Nuratau Range in Uzbekistan, part of the north-western spurs of the Pamir-Alay system. The entire known global population, estimated at about 1,000 to 1,500 individuals, is confined to three valleys in the central part of the range, giving the species an extent of occurrence and an area of occupancy of just 16 square kilometers each, among the smallest figures one can record before a species tips toward Critically Endangered territory. Species distribution modeling has shown that the plant occupies an extremely narrow ecological niche, tightly constrained by seasonal moisture availability, and that in dry years, which recur in the region every five to six years, almost no individuals flower or fruit at all. Under the high-emissions RCP8.5 climate scenario, the suitable range of the species is projected to shrink dramatically as the climate of the Nuratau region aridifies.

What makes the Lepidium assessment particularly striking is the intersection of threats it documents. Approximately 75 percent of the population sits within the Nuratau Nature Reserve, yet illegal grazing penetrates the reserve and its buffer zone, trampling seedlings and juvenile plants while indirect effects such as soil erosion and vegetation succession degrade the habitat. Separately, the thickened underground rhizome is harvested for medicinal and veterinary use, especially prized for treating racehorses in kupkari, the traditional Central Asian equestrian game, and the volumes harvested remain entirely unknown. Add avalanches and mudflows that regularly sweep seedlings off eroded slopes, and the picture is of a species squeezed from every direction. It qualifies as Endangered under criteria B and C combined, with all individuals in a single subpopulation. Perhaps most alarming for conservation planners: the species has never been cultivated ex situ, and not a single seed of it is conserved in any germplasm bank anywhere in the world.

The same gap between national protection and on-the-ground reality characterizes Parrya saxifraga, a pulvinate perennial endemic to the high-mountain Angren Plateau of western Tian-Shan in Uzbekistan, where it grows between 2,600 and 3,500 meters on eroded clayey-gravelly slopes in a zone of near-zero mean annual temperature. Only 17 occurrence records across 10 localities have ever been documented, and targeted expeditions between 2018 and 2025 failed to rediscover the species at four sites known only from herbarium specimens of the mid-twentieth century. A reduction analysis in GeoCAT estimates that the area of occupancy has declined by around 34 percent. The surviving population of roughly 1,500 to 2,000 mature individuals forms a single subpopulation dominated by adult and sub-senile plants, a demographic signature of poor recruitment. The threats now bearing down on it are distinctly modern: heavy summer pastoralism on alpine pastures, and two major infrastructure projects, a 600-hectare tourist complex called Arashan Resort whose construction near the Arashan lakes began in 2026, and a planned new toll road between Tashkent and Andijan near the Kamchik Pass that could affect one of the ten known locations.

Sardinia’s Phleum sardoum tells a different but equally instructive story, because here the new assessment actually lowered the risk category. The annual grass, endemic to coastal dune systems of western and northern Sardinia, had previously been assessed as Critically Endangered when only two localities were known. Recent surveys have revealed additional populations along the Trinita d’Agultu coastline, around Aglientu, in the Gulf of Asinara and in the Pistis dune system of the south-west, broadening the known footprint and justifying a move to Endangered under criterion B2b(iii,v)c(iv). But the numbers behind that category remain troubling: an area of occupancy of just 48 square kilometers, seven threat-defined locations based on recreational pressure, strong year-to-year swings in abundance, from 0.18 to over 20 plants per square meter in consecutive years of monitoring, and a documented decade-long decline in the southern populations. Summer tourism brings trampling and informal paths across the dunes, while invasive aliens such as Acacia saligna and Carpobrotus acinaciformis crowd out native dune vegetation at Rena Majore. Eight seed lots are preserved at the University of Cagliari’s seed bank, one of the few ex situ safeguards in this entire group of species.

Tanacetum ulutavicum, the Ulytau tansy, rounds out the list with a distribution that illustrates a subtle but deadly conservation problem: a species can look widespread on a map while being functionally confined to scraps of habitat. Its extent of occurrence in central Kazakhstan is a moderate 39,000 square kilometers, but its area of occupancy is only 136 square kilometers, concentrated in small granite-outcrop patches of roughly 207 to 1,200 square meters with densities as low as 0.06 individuals per square meter. Seeds lack dispersal structures such as a pappus, so populations stranded on rocky microsites embedded in unsuitable steppe have little chance of recolonizing lost patches. Grazing, trampling and unregulated recreation are degrading the remaining sites, and the assessment team concluded the species is severely fragmented in the formal IUCN sense. It joins the iris in being listed as Endangered under B2ab(iii,v).

Taken together, the five assessments sketch a portrait of plant extinction risk that is neither dramatic nor cinematic, but cumulative and quiet. The plants assessed here are threatened overwhelmingly by grazing pressure, land conversion, recreation, quarrying and shifting climate patterns, forces that act year after year on populations too small and too scattered to recover on their own. The assessors’ recommendations are correspondingly practical: regulate grazing during flowering and fruiting, restrict quarrying and construction within occupied habitats, map subpopulations to inform land-use planning, and above all build ex situ safeguards through seed banking and cultivation before options close. For a species like Lepidium olgae, whose rhizomes are being harvested for racehorses while its flowers fail in drought years, and for Parrya saxifraga, whose habitat is being transformed by a resort and a highway, the window for such measures is already narrowing. Each of these five Endangered listings represents a plant that science caught just in time, and a reminder that thousands more have yet to be counted at all.

Subject of Research: Global IUCN Red List conservation assessments of five endemic vascular plant species

Article Title: Global and Regional IUCN Red List Assessments: 20

Article References: Orsenigo, S., Beskho, N., Cogoni, D., Dubynin, A., Epiktetov, V., Khabibullaev, B., Khusniddin, A. S., Selyutina, I., Shomurodov, K., & Fenu, G. (2026). Global and Regional IUCN Red List Assessments: 20. Italian Botanist, 21, 255-277. https://doi.org/10.3897/italianbotanist.21.202195

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.21.202195

Keywords: IUCN Red List, plant conservation, endemic species, Central Asia, Sardinia, biodiversity, overgrazing, climate change, Iris kuschakewiczii, Lepidium olgae, Parrya saxifraga, Phleum sardoum