Assessment Notes

Justification

Cortinarius viridans is a strictly Mediterranean ectomycorrhizal fungal species with conspicuous large sporocarps, apparently with a narrow-endemic local distribution, being restricted to the montane forests of Cyprus, where the species occurs in association with the endemic Cyprus Cedar. Here, Cyprus Cedar is treated as a subspecies of Lebanon Ceder, Cedrus libani var. brevifolia which is assessed as VU on the IUCN Red List, based on its very small, geographically restricted population which makes it vulnerable to stochastic events. The small Cyprus Cedar forest patches currently are comprised of less than a dozen fragmented small populations in the Paphos forest, between 900 and 1,600 a.s.l. and may be threatened by forest fires and climatic changes. Cortinarius viridans is estimated to have a total population of <1,000 mature individuals and an area of occupancy of < 20 km2. Hence, the species qualifies to be red-listed as Vulnerable, based on a very small population restricted to a small area (D1 and D2).

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Taxonomic notes

Cortinarius viridans was described as new species in 2021, based on a monographic treatment of sect. Leprocybe in Europe, including extensive sampling in the Mediterranean region (Bidaud et al. 2021, cf. also Ammirati et al. 2021). The species is a close sister species to the frondose/Abies forest associate C. melanotus.

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Geographic range

Cortinarius viridans is so far known only from a handful of collections in Cyprus Cedar forests in the Troodos mountain range of Cyprus, being apparently restricted to a narrow altitudal range (900–1,600 m asl) in the western part of Cyprus (Bidaud et al. 2021). The species belongs to section/subgenus Leprocybe, a group which is now well-studied in Europe, with a recent monograph based on morphological and extensive fylogenetical data including the Mediterranean regions (Bidaud et al. 2021, cf. also Ammirati et al. 2021). It is thus unlikely that this species is much overlooked. However, a wider, Mediterranean distribution associated also with Cedrus libani, cannot be ruled out.

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Population and Trends

The species is so far known from 5 sites in montane Cyprus (Bidaud et al. 2021). Its ectomycorrhizal host tree, the Cyprus Cedar, occupies a small area within the altitudinal range of 900–1,600 m asl., and the real, total number of sites of Cortinarius viridans is estimated to not exceed 20 sites, each estimated to have fewer than 5 genetically unique fungi, corresponding to less than 1,000 fungal individuals according to IUCN standards (per Dahlberg and Mueller, 2011), with an area of occupancy of < 20 km². The Cyprus Cedar forests were formerly almost extinct, but have been locally re-planted, and the re-established forest patches are apparently at the moment not declining, but are very vulnerable to stochastic events, due to the extremely small and geographically restricted population.

Population Trend: unknown

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Habitat and Ecology

Cortinarius viridans is a Mediterranean species, recorded only from Cyprus Cedar forest fragments in montane Cyprus. The species is a putative ectomycorrhizal associate with Cyprus Cedar, Cedrus brevifolia (or Cedrus libani var. brevifolia). According to present knowledge, C. viridans is endemic to Cyprus, and this seems so far to be the only documented endemic Basidiomycota with an endemic tree host in the Mediterranean region (Bidaud et al. 2021). The small Cyprus Cedar forest patches are currently comprised of less than a dozen fragmented small subpopulations in the Paphos forest, between 900 and 1,600 a.s.l. (Hab. type 9590, Commission of the European Communities 2009) and may may also be restricted to serpentine and igneous substrates.

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Threats

Cortinarius viridans and its host, the Cyprus Cedar, occupies a very small area, and is vulnerable to stochastic events. Although the small Cyprus Cedar forests at the moment do not seem to be seriously declining, some dieback has been observed, probably due to long-term decrease in rainfall. Furthermore, in the future, the Cyprus Cedar and its associate, C. viridans may be threatened by forests fires and climatic changes, seriously affecting the altitudinal forest zonation of the Cyprus mountains (Christou and Garnder 2011, 2019). Based on some studies and technical reports, Cyprus Cedar forests are expected to be severely threatened during the first half of the 21^st century, as a result of reduced rainfall and climate warming (see Linares et al. 2011, Shoukri and Zachariadis 2012).

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Conservation Actions

To prevent the decline and fragmentation of the Cyprus Cedar forests with good habitat quality, it is important to set aside reserves with strict conservation, and it is preferential to also try to restore/establish some new sites within the optimal altitudinal zone (which may shift upwards in the mountain zonation with climate change). More surveying and monitoring of Cortinarius viridans are also needed, as well as monitoring of the status of montane forests with the endemic Cyprus Cedar, Cedrus libani var. brevifolia.

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Use and Trade

No use or trade is known.

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Source and Citation

Brandrud, T.-E. 2021. Cortinarius viridans. The IUCN Red List of Threatened Species 2021: e.T209474380A209474414. https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T209474380A209474414.en .Accessed on 27 December 2023

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• Country occurrence