Dirachma Socotrana—Back from the Brink?
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ORYX VOL 25 NO 4 OCTOBER 1991 Dirachma socotrana—back from the brink? M. Bazara'a, L. Guarino, A. Miller and N. Obadi Socotra, a small island in the Indian Ocean, is renowned for its remarkable flora. More than one-third of its 750 plant species are endemic, and seven are included in the IUCN Plant Red Data Book. Among these is Dirachma socotrana, which is something of a botanical curiosity. It was described in 1881 but confusion over its vernacular name led to the belief that it was widespread on the island. In 1989 the authors failed to find it in many of the sites where local people said it grew and on a second visit in 1990 the puzzle was resolved with the help of a linguist. In fact the species is apparently confined to one mountain pass. Although it is not immediately threatened it is, like many of the other plants on the island, at risk because of development plans. The small Indian Ocean island of Socotra has ered by a Scottish botanist, Sir Isaac Bayley long been renowned for its fascinating flora, Balfour, during his pioneering botanical expe- which includes such botanical curiosities as dition to the island in 1880. He collected only the cucumber tree Dendrosicyos socotrana and sterile material but was able to complete the the dragon's blood tree Dracaena cinnabari. description of the plant the following year Socotra, like many other oceanic islands, con- from flowering material collected by a tains a large number of endemic plant and ani- German explorer and naturalist, Georg mal species. There are approximately 750 Schweinfurth. Balfour was puzzled by the species of flowering plants and ferns recorded; affinities of the genus but on the basis of its of these over 250 are endemic. One of the most Geranium-like fruits placed it in the interesting of these is Dirachma socotrana—one Geraniaceae. Since then botanists have either of the seven species from Socotra recorded in placed it in a family of its own, the the IUCN Plant Red Data Book (Lucas and Dirachmaceae (e.g. Hutchinson, 1959), or Synge, 1978), where its status is categorized as treated it as an anomalous member of the endangered. It was considered to be the sole Geraniaceae (e.g. Cronquist, 1981). representative of the family Dirachmaceae, The name Dirachma was chosen by Balfour which White (1983) gives as the only endemic to reflect 'drachmam', the local name for the family in the Somalia-Masai regional centre of species given by Schweinfurth. The wood of endemism and which was, until recently, drachmam was noted for its sweet smell when thought to be endemic to Socotra. However, in burnt. In 1989 we found pieces of dried drach- 1979 another species was discovered in mam to be widely available on Socotra. Dead Somalia. This second species still awaits scien- wood (the living tree is never cut) is collected tific description. in the mountains and sold in the coastal settle- Dirachma socotrana is a small, white-flow- ments, where it is highly valued as an incense. ered, deciduous tree reaching about 3 m in We were told that it was quite common in the height. It is something of a botanical curiosity, mountains and were shown pieces of the possessing an interesting mixture of character- wood in most houses that we visited. istics. For example, the flowers have eight Balfour (1888) remarked that the species petals, sepals and stamens—an unusual num- was 'on the slopes of Haghier; not uncommon' ber in flowering plants, while the fruits closely and in view of this and the above comments it resemble those found in Geranium. seemed surprising that the tree was not seen Dirachma socotrana was originally discov- by any other collectors on the island until 1967 229 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.42, on 30 Sep 2021 at 06:01:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300034384 ORYX VOL 25 NO 4 OCTOBER 1991 when Radcliffe-Smith found about 30 trees in and the tree has little local importance. The the Muqadrihon Pass. However, Q. Cronk, bark may be stripped by goats in times of who briefly visited the island in 1985 under drought when better browse is unavailable the auspices of the WWF, failed to find the tree but this is the only use we recorded. Tifit is, in the Muqadrihon Pass. At the time of his according to local people, restricted to the area visit, however, the trees were not in leaf. He of the Muqadrihon Pass. In all, we counted was informed that the trees were cut for fire- some 30 trees in approximately 1 sq km. wood from the more accessible regions, but About 20 are found just inland of the highest that the tree was widespread in other areas of part of the pass, on a gentle south-west-facing the island and that in one spot there were over slope. Seven were found on limestone cliffs to 1000 trees. the north-west of the pass. Isolated trees were In 1989 the authors visited the island and also found on steep granite slopes to the tried to assess the status of the species. The south-east and along the path going up to population at Muqadrihon was found again Muqadrihon from the coastal plain. The area and we were also told by informed local peo- is heavily wooded and there could well be ple that drachmam was widespread on the more trees, but the total population is certain- island. We were therefore rather perplexed at ly very low. Following several years of not being able to find it in any of the sites to drought, the area is fairly heavily grazed and which we were led. no regeneration was noted. It was only in 1990, after again visiting The Muqadrihon Pass is probably the Muqadrihon with a linguist, Dr Miranda wettest area on the island and has the most Morris, that we were able to resolve the mys- luxuriant vegetation. It crosses, in a north- tery. Drachmam is, in fact, the dried wood of east/south-west direction, from the Hadibon 'tahn' Cephalacroton socotmna (Euphorbiaceae), plain on the north coast to the Wadi Ayhaft, a relatively widespread endemic tree. The ver- which runs to the interior of the island. It also nacular name of Dirachma socotrana is 'tifit', marks the junction of the granite of the (r* 0 50 100 km 1 I I Sam hah Abd al Kuri Darsa Map showing location of Socotra off the north-east coast of Africa. 230 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.42, on 30 Sep 2021 at 06:01:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300034384 DIRACHMA SOCOTRANA—BACK FROM THE BRINK? View of the Muqadrihon Pass, showing dragon's blood trees Dracaena cinnabari (A. Miller). Haggier Mountains and the limestone of the are all ncluded in the IUCN Plant Red Data Reiged Plateau so that the slopes above the Book (Lucas and Synge, 1978). pass are granite to the south-east and lime- The low number of known trees and the stone to the north-west. The vegetation is lack of natural regeneration is obviously a dense, semi-deciduous, submontane thicket cause for serious concern for the long-term with emergent Dracaena cinnabari and dominat- survival of the species. Any changes in the ed by Buxus hildebmndtii, with Cephalocroton area such as the building of a road through the socotranus, Acacia pennivenia, Arthrocarpum Muqadrihon Pass or the digging of new wells gracile, Ormocarpum dhofarense, Rhus thyrsiflora, could rapidly lead to the extinction of this Boswellia ameero, Ficus vasta, Jatropha unicostata, species. At present, however, the existing trees Carphalea obovata, Commiphora ornifolia and C. are under no immediate threat. The socotrana. With the exception of the Ficus and Muqadrihon Pass cannot be reached by car Buxus, all the species mentioned above are and traditional restraints against the cutting of endemic. Several other rare and endangered live trees are still generally adhered to. Of the species are found in the Muqadrihon Pass trees we examined, about half had some of including, for example, Indigofera socotrana, their bark stripped by goats but otherwise which is known only from there and one other seemed quite healthy. place on the island, and Punica protopunica (a In general it is encouraging to record that very rare wild relative of the pomegranate and the vegetation in many parts of the island is the only other member of the family still relatively healthy and not suffering the Punicaeae), which has its largest population devastation experienced on nearby mainland here—about 12 trees. On the cliffs above the Africa and southern Arabia. In the majority of Pass are large populations of Dorstenia gigas areas where the vegetation has been most and Begonia socotrana. The last three species obviously altered the indications are that this 231 Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.42, on 30 Sep 2021 at 06:01:15, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605300034384 ORYX VOL 25 NO 4 OCTOBER 1991 is not a recent event and that there has been of important and endangered species, and no dramatic change since Balfour's time. Socotra is included in these efforts. The It is impossible at present to be able to com- planned measures would include establishing ment on the past distribution of Dirachma on a nursery on the island where the numbers of Socotra.