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Bradleya 32/2014 pages 81–91 A preliminary assessment of the conservation status of the genus Aloe L. in Madagascar Solofo E. Rakotoarisoa 1, Ronell R. Klopper 2,3 & Gideon F. Smith 2,4,5 1 Millennium Seed Bank Project, Royal Botanic Gardens Kew, Kew Madagascar Conservation Centre, Lot II J 131 B, Ambodivoanjo, Ivandry, Antananarivo, Madagascar. (email: [email protected]). 2 Biosystematics Research and Biodiversity Collections Division, South African National Biodiversity Institute, Private Bag X101, Pretoria, 0001 South Africa. (email: [email protected]). 3 H.G.W.J. Schweickerdt Herbarium, Department of Plant Science, University of Pretoria, Pretoria, 0002 South Africa. 4 Centre for Functional Ecology, Departamento de Ciências da Vida, Universidade de Coimbra, 3001-455 Coimbra, Portugal. (email: [email protected]) 5 Department of Botany, P.O. Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth, 6031 South Africa. Summary : The island of Madagascar harbours Zusammenfassung : Die Insel Madagaskar ist die 128 species (161 taxa) of Aloe L., which are all en - Heimat von 128 Arten (161 Taxa) von Aloe L., und demic to this biodiversity hotspot. Most Malagasy alle sind in diesem Biodiversitäts-Hotspot en - aloes have very restricted distribution ranges and demisch. Die meisten madagassischen Aloen are represented by small populations. Madagas - haben eine sehr beschränkte Verbreitung und can aloes are very popular in horticulture and an sind durch kleine Populationen gekennzeichnet. important part of the ornamental plant export in - Madagassiche Aloe-Arten sind im gärtnerischen dustry. The aloes of Madagascar are prone to Bereich geschätzt, und sie stellen einen wichtigen human pressures that affect the degradation of Teil der Zierpflanzenexportindustrie dar. Die their natural habitats and their survival. How - Aloen von Madagaskar werden durch anthropo - ever, there has not been a treatment to assess the gene Faktoren bedrängt, welche zur Degradation conservation status of the Malagasy aloes. Here, ihrer Standorte führen und das Überleben for the first time, we aim to provide a risk assess - gefährden. Bisher gab es jedoch keine formelle ment and make available preliminary conserva - Beurteilung des Gefährdungsstatus' der mada - tion statuses for all the known aloes of gassichen Aloen. Hier versuchen wir für das erste Madagascar. Specimen information from different Mal überhaupt eine Beurteilung der Risiken, und herbaria and different websites have been gath - wir machen für alle bekannten madagassischen ered and compiled into a BRAHMS database. The Aloen eine vorläufige Einschätzung des Conservation Assessment Tool was used for data Gefährdungsstandes. Es wurden Angaben zu analysis during the conservation assessments. It Belegen aus verschiedenen Herbarien und von was found that around 39% of Madagascan aloes verschiedenen Webseiten zusammengetragen und are threatened, with only 4% being Least Con - in eine BRAHMS-Datenbank zusammengestellt. cern. Of great significance is the fact that almost Das Werkzeug für die Beurteilung des 50% of the aloes in Madagascar are regarded as Gefährdungsstatus wurde dann während der Data Deficient, likely leading to a huge underes - Evaluation zur Datenanalyse verwendet. Es timate of the percentage of threatened aloes. Fur - zeigte sich, dass rund 39% der madagassischen ther research into Data Deficient taxa and a Aloe-Arten gefährdet sind, und nur 4% gehören in comprehensive conservation assessment for all die Kategorie "Least Concern". Von besonderer the aloes of Madagascar is required. These results Wichtigkeit ist die Tatsache, dass für fast 50% der will inform priorities in conservation projects con - madagassischen Aloen unzureichende Angaben cerning aloes and the areas where they occur. vorhanden sind, was wahrscheinlich zu einer deutlichen Unterschätzung des Prozentsatzes gefährderter Aloen führt. Es braucht weitere Un - Bradleya 32/2014 81 Figure 1. Aloe suzannae from southern Madagascar is Figure 2. Aloe helenae from southeastern Madagascar one of only two Madagascan aloes currently included in is currently listed as Critically Endangered on the IUCN the IUCN Red Data List. It is listed as Critically En - Red Data List. Photograph: D. Rabehevitra. dangered. Photograph: S.E. Rakotoarisoa. treatment of the genus in Madagascar was pro - tersuchungen dieser "Data Deficient"-Taxa sowie duced by Perrier de la Bathie in 1926 (Perrier de umfassende Einschätzungen des Gefährdungssta - la Bathie, 1926), followed by an updated Flora tus' aller madagassichen Aloen. Diese Resultate treatment in 1938 (Perrier de la Bathie, 1938a ergeben die Grundlage für die Prioritätensetzung & b). The third treatment of the aloes of Mada - bei Schutzprojekten für Aloe sowie die Gegenden, gascar followed in 1966 when Reynolds produced in welchen sie vorkommen. his epic second volume on the genus (Reynolds, 1966). Thereafter, apart from the inclusion of Introduction several aloes in a two volume work on the suc - In Madagascar, the genus Aloe L. comprises culent and xerophytic plants of Madagascar by 128 species and 161 taxa of which all are en - Rauh (Rauh, 1995, 1998), only small publica - demic to the island (Aloes of the World Data - tions describing new aloes appeared. Between base, 2014). These plants are highly sought-after 2000 and 2010, approximately 54 new taxa were by both foreign and Malagasy horticulturists. validly described and eight new combinations Aloes represent 5% of exported succulent orna - published. A further 19 new names, which are mental plants, which in turn constitutes 86% of now treated as synonyms, were also published the total ornamental plants exportation from during this time (Aloes of the World Database, Madagascar (Rasoanaivo et al ., in press). 2014). The latest large-scale treatment of Mada - Scientists have been fascinated by Malagasy gascan aloes is that of Castillon & Castillon aloes for just over 150 years: the first collection (2010). Since the appearance of this book, a fur - of an aloe in Madagascar was made in 1848 by ther fifteen new aloes and two new combinations Boivin [ Aloe occidentalis (H.Perrier) L.E.Newton were published (Aloes of the World Database, & G.D.Rowley, Boivin, L.H. 2336 (P)]. The first 2014) (see Table 1). 82 Bradleya 32/2014 Figure 4. Aloe bernadettae from southeastern Mada - Figure 3. Number of Aloe taxa in the different IUCN gascar is a Data Deficient species that used to be com - categories. (EW: Extinct in the Wild; CR: Critically En - mon, but has now seemingly become scarce. dangered; EN: Endangered; VU: Vulnerable; NT: Near Photograph: R. Letsara. Threatened; LC: Least Concerned; DD: Data Deficient) to the conservation of these aloes. All other aloes In Madagascar, research on the genus proves are listed on Appendix II (CITES, 2014). to be challenging, mainly because of the paucity Currently, only two Madagascan aloe species of herbarium material held locally: 95 taxa are appear on the International Union for Conserva - represented by only one collection, and 20 species tion of Nature (IUCN) Red Data List, namely Aloe were not collected during the past 40 years. The suzannae Decary (Figure 1) (Smith & Swartz, question remains whether these aloes have dis - 1997, 1999; Smith et al ., 1999) and A. helenae appeared in nature, or if they are only rarely col - Danguy (Figure 2), and both are assessed as Crit - lected by botanists. ically Endangered D (IUCN, 2014). This list is not Except for a few species (less than 10), the up to date as far as the aloes of Madagascar are Malagasy aloes have very restricted distribution concerned, owing to the vast number of new aloes ranges. Furthermore, most species are repre - described from this island in the past few sented by a small population. These factors make decades. Another reason is the absence of a full the genus more vulnerable to human pressures assessment of the conservation statuses of Mala - such as bush fires and illegal collecting of wild gasy aloes. Currently, three Madagascan aloes plants for commercial purposes. In addition, dif - have become extinct in the wild (namely A. oligo - ficulty of regeneration of populations constitutes phylla Baker, A. schilliana L.E.Newton & Row - a real danger of extinction of aloes. The majority ley and A. silicicola H.Perrier), while numerous of aloes (43%) are found on the Malagasy high species are threatened with extinction through plateau and only 7% are recorded from the East. the destruction of their natural habitats (Castil - Much of the natural vegetation on the central lon & Castillon, 2010). high plateau has been destroyed for rice cultiva - Conservation assessments have become in - tion and the remaining grasslands are burned an - creasingly essential tools to provide a framework nually to provide grazing for zebu (cattle), which for conservation planning, management, moni - play a huge part in the life and rituals of the toring and decision-making (Callmander et al ., Malagasy people (Rauh, 1995). The aloes of 2005; Rodrigues et al ., 2006). For this reason the Madagascar are thus prone to human pressures World Conservation Congress, held in Thailand that affect the degradation of their natural habi - in 2004, mandated the development of new appli - tats and their survival. cations for Red Lists in national and interna - All species of Aloe [except for A. vera (L.) tional legislation, development policies, Burm.f] appear on the Appendices of the Conven - conservation planning and scientific research (Ro - tion on the International Trade in Endangered drigues et al ., 2006). Even though plants play an Species of Wild Fauna and Flora (CITES). This essential role in ecosystem structure as the basis means that trade in aloes is controlled to prevent of all life on earth, only a small percentage of utilisation that would be incompatible with their plants have been assessed globally (Callmander survival. Of the 21 aloe species listed on Appendix et al ., 2005). Therefore, Target 2 of the Global I (CITES, 2014), a total of 17 are Malagasy Strategy for Plant Conservation (GSPC) calls for species. This is an indication of the huge threat “an assessment of the conservation status of all Bradleya 32/2014 83 Figure 6.