Cyclamen Colchicum (Albov) Correvon - Field Study 2013
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CyclamenT h e S o c i e t y Cyclamen colchicum (Albov) Correvon - Field Study 2013 Martyn Denney, The Cyclamen Society, United Kingdom Manana Khutsishvili, Ilia State University Institute of Botany, Republic of Georgia 20 October 2013 Interim Report 1 Background Cyclamen L. are a genus in the family of Primulaceae of from 23 to 29 species depending upon the taxonomy adopted for subgenus Gyrophoebe Schwarz, series Pubipedia Schwartz. Cyclamen colchicum (Albov) Correvon is a late summer flowering species that is endemic to Abkhazia, Zemo- Svaneti, Samegrelo and Racha-Lechchumi in the Republic of Georgia. It was first described by the Russian botanist Nicolai Albov from the Gorge of the Okumi River in Abkhazia initially in 1894 as Cyclamen europaeum var. ponticum and in 1895 as C. europaeum var. colchicum . The same year, his friend Henry Correvon elevated it to specific level in his name. Albov also said that Cyclamen europaeum var. typicum (= C. purpurascens Mill.) was found on the high mountains of Samegrelo, an opinion shared by Otto Schwartz from Jena (Denney 2012). The Herbaria of the Ilia State University Institute of Botany (TBI) and the Simon Janashia State National Museum of Georgia (TGM) hold specimens of C. colchicum recorded from a number of locations in Samegrelo which – with the exception of recently discovered populations in the Khobistskali Gorge (Trivedi & Mikatadze- Pantsulaia 2012) – had not been visited by botanists in recent years, in some cases for several or many decades. The objects of the 2013 Field Study carried out from 15-26 August 2013 were to (a) confirm the current distribution and conservation status of Cyclamen colchicum , and in particular whether populations continue to exist at the historic sites; and (b) establish whether there are one or two species of late summer flowering cyclamen in the study area. 2 Habitat 2.1 Geology and Growing Medium Cyclamen colchicum only grows on Upper Jurassic and Cretaceous limestone rocks or where the underlying rock is limestone. All known sites are on this strata and attempts to locate populations of Cyclamen colchicum on adjacent non-calcareous sedimentary rocks failed. Although at all sites visited C.colchicum was closely associated with limestone rock, often growing in tiny crevices or accumulations of soil with the rock, the pH values of the growing medium itself varied from 6.5 – 7.9 and in most locations was largely inorganic. Leaching by rainfall would tend to remove the alkaline components, lowering pH, and this would be enhanced by the increasing organic content. The organic matter that was present was generally fragments of plant roots, mosses and sometimes leaves or rotting wood. An analysis of growing media at the sites visited can be found in Appendix 2. 2.2 Altitude Nicolai Albov described Cyclamen colchicum at its locus classicus in the Okumi River Gorge at an altitude of 300m. He also recorded what he called Cyclamen europaeum var. typicum (= C. purpurascens Mill.) at between 1800 - 2000m. on Migaria and Dzhwari (= Jvari), 1980 – 2000m. on Kwira (= Kvira), 2400m. on Aschi (= Askhi) and between 2400 – 2500m. on Ocháczkue (= Okhachkue). During the 2013 field study using GPS devices with a typical 3D accuracy of ±10m. C. colchicum was recorded at altitudes ranging from 450 – 1928m. 2.3 Aspect, Slope and Shade The majority of Cyclamen colchicum were growing in open conditions with shade provided only by their aspect if the degree of slope was sufficient for this. At these sites the degree of slope varied from vertical (90 °) to approximately 35 ° A few plants at the bottom of some sites were shaded by shrubs or juvenile trees. With the exception of two locations the plants were found growing at sites in the easterly half of the compass, ranging from north-northeast round to south-southeast. One high altitude (1980m.) alpine meadow site (see section 4.2.1) was very open with a minimal slope and protection only offered by the small rocks, rock outcrops and other plants which had little or no effect on the amount of light reaching the plants. Here, the generally south-southwesterly aspect of the site would be insignificant. One low altitude (450m.) site on a cliff high above a river (see section 4.1.2.1) where the majority of the plants were growing on a large ledge at an approximate angle 45 ° had an aspect of northwest. There is no explanation for this anomaly. 3 Distribution Cyclamen colchicum is currently confined to the eastern part of Abkhazia, Samegrelo and southwest Svaneti – with the exception of one high altitude population a few hundred metres inside the extreme west of Racha- Lechkhumi. Unfortunately the populations in Abkhazia and in the mountains west of the Enguri River are not currently accessible to western or Georgian botanists. Due to pressures of time and economics the study was carried out by following forest tracks rather than exploring on horse-back or hiking. Necessarily therefore, the sites found represent a cross-section through the forest and mountain areas and almost certainly are indicative of wider populations where the habitat is correct in the same general area. Sites found fall roughly into two categories: Relatively low level river valley locations and high level alpine meadows. GPS co-ordinates for these sites are in Appendix 1 (restricted circulation). Herbarium voucher specimens for all sites visited by the team are held at TBI. One site not visited by us but recorded in August 2012 by Sandro Kolbaia is also noted below. Areas visited but where no Cyclamen colchicum were observed are also listed. 3.1 River Valleys & Gorges 3.1.1 Khobistskali Gorge A site in the Khobistskali Gorge was originally recorded by Manana Khutsishvili, 08-10-2010. Herbarium voucher specimen held at TBI Three populations were observed by the team at altitudes between 600 – 630 m. 3.1.1.1 Site at 606m. (Cyclamen Society reference 13/01) A small population of less than 100 plants of Cyclamen colchicum growing on limestone cliffs in rock crevices and on ledges in accumulations of soil with a high mineral content and rock fragments. Relatively dry open conditions with some plants in approximately 25% shade provided by shrubs & juvenile trees. Aspect south-southeast; slope from vertical to 45 °. Soil pH: 6.7 Some natural regeneration with juvenile plants at the 2-3 leaf stage. Principal companion plants: Alnus barbata (syn. Alnus glutinosa subsp. Barbata), Rhododendron ponticum, Philadelphus caucasicus (syn. Philadelphus coronaries), Hedera colchica, Rubus sp ., Polypodium vulgare, Asplenium trichomanes 3.1.1.2 Site at 622m. (Cyclamen Society reference 13/02) A population of possibly between 100 - 200 plants of Cyclamen colchicum growing on limestone cliffs both in the main valley and the gorge of a tributary stream, in rock crevices and on ledges amongst mosses in accumulations of soil consisting of a brown loam with rock fragments. Relatively dry open conditions with an easterly aspect in the main valley with the majority of plants on inaccessible high open rock ledges, but a few low level plants shaded by juvenile trees. In the tributary gorge, C. colchicum was growing in damper conditions in rock crevices and on ledges in 25-50% shade with a north-northeast aspect Soil pH: 6.7 Khobistskali Gorge : Herbarium voucher specimen held at TBI. Manana Khutsishvili, 8th October 2010. Strong evidence of natural regeneration with juvenile, white, 1-5mm tubers in rock crevices and semi- mature seedlings scattered around parent plants. Principal companion plants: Alnus barbata (syn. Alnus glutinosa subsp. Barbata), Castanea sativa, Ilex colchica, Rhododendron ponticum, Laurocerasus officinalis, Philadelphus caucasicus (syn. Philadelphus coronaries), Hedera colchica, Brunnera macrophylla, Rubus sp . 3.1.1.3 Site at 630m. (Cyclamen Society reference 13/03) A small population of less than 100 plants of Cyclamen colchicum growing on open ledges on a north- northeast facing limestone cliff in the main valley and in approximately 50% shade on the damp north facing side of the dry gulley of a seasonal tributary stream. Soil pH: 6.5 Some natural regeneration with seedlings observed in the tributary gulley. Principal companion plants: Laurocerasus officinalis, Rhododendron ponticum, Hedera colchica, Rubus caucasicum, Hypericum androsaemum, Pteris cretica, Phyllitis scolopendrium, Asplenium trichomanes 3.1.2 Tekhura River Valley towards Lebarde A site at an altitude of 700m. was originally recorded by Moisei Sokhadze, 08-08-1965. Herbarium voucher specimen held at TGM Three populations were found by the team at altitudes between 450 – 920m. 3.1.2.1 Site at 450m. (Cyclamen Society reference 13/05) An inaccessible thriving population high on a northwest facing limestone cliff above the River Tekhura. Cyclamen colchicum growing on two or three ledges (one very large) in accumulations of soil. Visible companion plants: Populus sp., Staphylea colchica, Castanea sativa, Picea orientalis 3.1.2.2 Site at 470m. (Cyclamen Society reference 13/06) A small population of apparently less than 50 plants growing on a limestone cliff, limestone scree and in humus-rich soil amongst mosses under shrubs. A site with a southeast aspect with open scree & cliff areas, and an area under shrubs with up to 75% shade. Generally damp conditions both under the surface of the scree and in the shaded areas. Soil pH: 7.9 Evidence of minor atural regeneration in shaded areas. Principal companion plants: Smilax excelsa, Carpinus caucasica (syn. Carpinus betulus), Buxus colchica (syn. Buxus sempervirens), Hedera colchica, Andrachne colchica (syn. Leptopus colchicus) 3.1.2.3 Site at 920m. (Cyclamen Society reference 13/07) A site extending over several hundred horizontal metres from an altitude of approximately 920m. to 933m. Cyclamen colchicum growing in accumulations of a dark brown humic loam with rock fragments on ledges on near vertical limestone outcrops and low cliffs with a generally easterly aspect with grasses below.