Gyalectidium colchicum Vězda, 1983, Folia Geobot. Phytotax. 18(1): 58.
Type: U.R.S.S. Rossia merid., Colchis (Transcaucasia occid.), distr. Lazarevskoje: in faucibus rivi Dagomys Zapadnyi, supra vicum Tretja Rota [Tret’ya Rota]. [WGS 84: 43.7419, 39.6814]. Ad folia Buxi colchicae. 1979/6/25 Vězda, A.
Gyalectidium colchicum, is in a state of regression throughout the Black Sea coast region due to anthropogenic pressure, mainly the development of tourism, deforestation, the construction of Olympic facilities in Sochi 2014. Species is strictly associated with old-grown evergreen forests in Caucasus and Macronesia. It has been red-listed VU B1b(iii) in Russia (Krasnodar Area) because its distribution area is fragmented and some populations have disappeared given the loss of their natural habitat (Urbanavichus, 2006). According to monitoring, the Black Sea population has a rapid declined during 2012-2013.
It has been known only from the western part of the Caucasus (Russia, Abkhazia, Georgia), adjacent areas of the Black Sea coast of Turkey (Trabzon and Rize provinces) and Macaronesia (Portugal - Azores: Terceira and São Miguel; Madeira; Spain - Canary Islands: Gomera and La Palma)
Russia: the Black Sea coast of Krasnodar Area, W Caucasus (Vězda, 1983; Urbanavichus, 2006). Caucasian population rapidly declined.
Turkey: Trabzon and Rize provinces (Aslan et al., 2005). Unknown population trend.
Portugal: Azores (Terceira and São Miguel), Madeira. Unknown population trend.
Spain: Canary Islands (Gomera and La Palma). Unknown population trend.
Population Trend: Deteriorating
It is foliicolous species prefer to grow on leaves evergreen trees and shrubs (Buxus colchica and Laurocerasus officinalis in the Black Sea coast and Laurus azorica in Macaronesia). Species is strictly associated with virgin wet Buxus forests (the Black Sea coast from Russia to Turkey) and old-grown mountain cloud forests (Macaronesia) with numerous relicts species.
It is threatened by habitat loss caused by a catastrophic defoliation of Buxus trees, forestry (legal and illegal logging), road development, the construction of Olympic facilities in Sochi 2014, and climate change.
Study of population trends are needed across its distributional range. Response to climate change and habitat loss have to be studied.
Aslan, A., Vězda, A., Yazici, K., Karagoz, Y. 2005: New foliicolous lichen records for lichen flora of Turkey. - Cryptogamie, Mycologie 26(1): 61-66.
Ferraro, L.I., Lücking, R., Sérusiaux, E. 2001: A world monograph of the lichen genus Gyalectidium (Gomphillaceae). - Botanical Journal of the Linnean Society 137: 311-345.
Urbanavichus, G. P., Urbanavichene, I. N. 2012: Addition to the lichen flora of Abkhazia and Caucasus. – Vestnik Tver State University. Ser. Biology and Ecoligy. 27: 109-116.
Vězda, A. 1983: Foliicole Flechten aus der Kolchis (West-Transkaukasien, UdSSR). - Folia Geobotanica et Phytotaxonomica 18: 45-70.
Urbanavichus, G. P. Gyalectidium colchicum – In: Red Data Book of Krasnodar Area. Krasnodar: 385.