Flora diversity of Mount Bar Le Duc Volcanic Crater (Ripailles Hill), Nouvelle Découverte, Mauritius.

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1 Cahiers scientifiques de l'océan Indien occidental 4, 2013 : Flora diversity of Mount Bar Le Duc Volcanic Crater (Ripailles Hill), Nouvelle Découverte, Mauritius. KERSLEY PYNEE¹, JEAN-YVES DUBUISSON² AND SABINE HENNEQUIN² 1- Mauritius Sugarcane Industry Research Institute, Mauritius Cane Industry Authority, Réduit, Mauritius. Current address: The Mauritius Herbarium, Agricultural Services, Ministry of Agro-Industry and Food Security, Réduit, Mauritius. kpynee@mail.gov.mu 2- Université Pierre et Marie Curie, UMR 7207 CNRS-MNHN-UPMC Centre de Recherches en Paléobiodiversité et Paléoenvironnements, 57 rue Cuvier, CP48, Paris, France. jdubuiss@snv.jussieu.fr; shennequ@snv.jussieu.fr Reçu le 25/01/2013, accepté le 19/05/2013 ABSTRACT: The Mount Bar Le Duc volcanic crater is a remnant of 0.7 ha of native vegetation found within a larger disturbed and fragmented area of nearly 300 ha. A checklist of both native and alien plants was compiled for this study area. Botanical surveys carried out from at this volcanic crater showed a total of 68 species of native plants from 42 families distributed on 62 genera. Of this, 48 species were angiosperms (30 families, 45 genera) and 20 were pteridophytes (12 families, 17 genera). The most species-rich families were Rubiaceae, Myrtaceae and Orchidaceae; and for the ferns, it was Hymenophyllaceae. For alien species, 28 species of 22 families and 26 genera were recorded. RÉSUMÉ : Le cratère volcanique du Mont Bar Le Duc est une zone vestige de 0,7 ha de végétation indigène dans une plus grande zone perturbée et fragmentée de près de 300 ha. Une liste de plantes indigènes et exotiques a été compilée pour cette zone d'étude. Les relevés botaniques effectués depuis sur le Mont Bar Le Duc ont révélé un total de 68 espèces de plantes indigènes pour 42 familles et 62 genres : 48 espèces d'angiospermes (30 familles, 45 genres) et 20 espèces de ptéridophytes (12 familles, 17 genres). Parmi les angiospermes, les familles les plus riches en espèces sont les Rubiacées, les Myrtacées et les Orchidacées. Parmi les fougères, les Hymenophyllacées. Pour les espèces exotiques, 28 espèces, avec 22 familles et 26 genres, ont été enregistrées. KEYWORDS: habitat fragmentation, native species, Mascarenes, conservation. MOTS CLÉS : morcellement de l'habitat, espèces indigènes, Mascareignes, conservation. INTRODUCTION Mauritius (20.25 S, 57.5 E), a volcanic island, is one of the Mascarene islands together with Rodrigues and Réunion, located in the south west of the Indian Ocean (CHEKE & HUME, 2008). It is nearly 60 km long by 40 km wide, representing an area of 1865 km². Through three phases of volcanic activity, the emergence from the sea floor and other extensions of the island s area gave rise to primary craters, still recognizable from the Black River Mountain Ranges with the highest peak at 828 m, to the Moka Range and to some isolated peaks nearby (SADDUL, 1995). Globally, volcanic craters are known for their importance in the maintenance of biodiversity or to act as lakes and natural water reservoirs (DUKER & BORRE, 2001). In Mauritius, 36 craters have been identified, including eight which are well preserved, 14 less conserved but still easily recognisable, nine partially flooded but highly degraded and five are probable sites of old craters

2 16 Flora diversity of a volcanic crater, Mauritius K. PYNEE, J.-Y. DUBUISSON & S. HENNEQUIN (WILLAIME, 1984). Recently, a study at Kanaka Crater through peat coring and pollen analysis, reveals the island s environmental and climatic changes of the last 38,000 years (VAN DER PLAS et al., 2012). From the botanical point of view, and considering the only six voucher specimens from the Bar Le Duc crater harbored at The Mauritius Herbarium collected from , boosted me up to start updating our collection for this locality. Moreover, the purpose of such a survey was to obtain more detailed information and knowledge on the floral diversity of the said crater. MATERIALS AND METHODS STUDY AREA The Mount Bar Le Duc (Ripailles Hill) is a non-active volcanic crater located in the district of Quartier Militaire, next to Nouvelle Découverte, in the centre of Mauritius (WILLAIME, 1984) (Fig. 1a). It is an area composed of approximately 0.7 ha, situated between coordinates S and E and at an elevation ranging from 421 to 596 m above sea level. Its climate is relatively warm to humid, with a mean annual temperature of 25ºC, and annual rainfall between 2600 and 2800 mm (WILLAIME, loc. cit.). The studied area is a remnant of 0.7 ha of native vegetation found within a larger disturbed and fragmented area of nearly 300 ha. The fragmented area is a privately owned reserve and used for deer ranching (Cervus timorensis Blainville, 1822) and is surrounded by pastures, sugar cane fields, vegetables, pinus and eucalyptus plantations, and with very few native individuals of Ficus mauritiana (Moraceae) dispersed around. Figure 1. 1a) Photo showing volcanic crater of Mount Bar Le Duc ; 1b) flower of Roussea simplex (Rousseaceae)

3 Cahiers scientifiques de l'océan Indien occidental 4, 2013 : BOTANICAL SURVEY Qualitative vegetation survey through random sampling, comprising six days of fieldwork, were carried out in 2011 and The identification of species was done using mainly the Flore des Mascareignes (BOSSER et al., 1976 onwards) and Les Graminées des Paturages et des Cultures à Madagascar (BOSSER, 1969) and also by comparison with herbarium specimens. Voucher specimens of each species are deposited at The Mauritius Herbarium. Undetermined species are also included in the list. RESULTS AND DISCUSSION For the native plants, 68 species (42 families, 62 genera) including three undetermined species and one cryptogenic species were collected and accessed (Table 1 and 2). This botanical survey gave rise to 28% species endemic to Mauritius, 18% endemic to Mauritius and Réunion Island, 47% indigenous, two percent cryptogenic and four percent undetermined. Among the native angiosperms, 48 species (30 families, 45 genera), the most species-rich families were Rubiaceae, Myrtaceae and Orchidaceae (five species each), followed by Euphorbiaceae (four species), Poaceae (three species) and Urticaceae (two species) (Table 1). The richest genera were Angraecum (three species), Eugenia and Syzygium (two species each). In the case of the 20 native pteridophytes (12 families, 17 genera), the richest families were Hymenophyllaceae (four species), followed by Pteridaceae and Thelypteridaceae (three species each), and Lomariopsidaceae (two species) (Table 2). The richest genera were Cyclosorus (three species), and Nephrolepis (two species). The alien species (28) recorded in the surveyed area belong to 22 different families (Table 3). CONCLUSION The botanical survey carried out at Mount Bar Le Duc crater has increased the herbarium collections as well as our knowledge of the crater s vegetation. Some new records, comprising very rare native species (e.g. Roussea simplex, Fig. 1b) which are considered as Endangered according to the International Union for the Conservation of Nature criteria (IUCN 2001) are also collected and recorded. Further similar surveys in other craters of Mauritius should also be envisaged, which in turn, will provide valuable information, regarding future conservation measures for these habitats. ACKNOWLEDGEMENTS Special thanks to Drs Salem Saumtally and Asha Dookun-Saumtally for their support to KP. Dr Claudia Baider provided suggestions for improving the manuscript. We are also grateful to the owner, Director and staff at Bar Le Duc, especially to Mr Jean-Patrick Lesur, for their usual collaboration and permission to access the site. I sincerely appreciate the help of Messrs Cedric Soutif, Darmanand Sooklall, Isoop Damry and Ms Karen Martial during fieldworks.

4 18 Flora diversity of a volcanic crater, Mauritius K. PYNEE, J.-Y. DUBUISSON & S. HENNEQUIN Table 1. List of native angiosperms from Mount Bar Le Duc Crater. Status: (C) Common (individuals > 50), (O) Occasional (50 < individuals >10), (R) Rare (5< individulas < 10) and (VR) Very Rare (individuals < 5). Origin: Cryptogenic (C), Indigenous (I), Endemic to Mauritius (MAU), Endemic to Mauritius and Réunion (MAU, REU), Mascarenes (MAS) and Undetermined (U). IUCN criteria: Critically Endangered (CR), Endangered (EN), Vunerable (VU), Near Threatened (NT),, Data Deficient (DD) and Not Evaluated (NE). Barecode no. Family Taxa Life form Statut at Mt B. le Duc Origin MAU Achariaceae Erythrospermum monticolum Thouars var. pyrifolium (Lam. ex Poiret) Sleumer S R MAU NT MAU Aphloiaceae Aphloia theiformis (Vahl) Benn. S VR I LC MAU Apocynaceae Tabernaemontana persicariifolia Jacq. S VR MAU, REU EN MAU Asteraceae Faujasiopsis flexuosa (Lam.) C. Jeffrey subsp. flexuosa S VR MAU LC MAU Bignoniaceae Colea colei (Bojer ex Hooks) M. L. Green S VR MAU EN MAU Connaraceae Cnestis glabra Lam. L R I LC MAU Elaeocarpaceae Elaeocarpus integrifolius Lam. T VR MAU CR MAU Erythroxylaceae Erythroxylum macrocarpum O. E. Schulz S VR MAU LC MAU Euphorbiaceae Orfilea neraudiana (Baillon) Webster T VR MAU - MAU Euphorbiaceae Hancea integrifolia (Willd.) S. E. C. Sierra, Kulju & Welzen S VR MAU, REU EN MAU Euphorbiaceae Acalypha integrifolia Willd. subsp. marginata (Poiret) Coode var. marginata (Poiret) Coode S VR MAU EN MAU Euphorbiaceae Macaranga mauritiana Bojer ex Baill. T VR MAU EN MAU Hypoxidaceae Hypoxis angustifolia Lam. var. angustifolia H O C NE MAU Lauraceae Ocotea aff. mascarena (Buchoz) Kostern S VR MAU EN MAU Laxmanniaceae Cordyline mauritiana (Lam.) Macbride S VR MAU, REU EN MAU Loganiaceae Geniostoma pedunculatum Bojer ex DC. S VR MAU, REU MAU Melastomataceae Memecylon sp S VR MAU MAU Moraceae Ficus mauritiana Lam. T R MAU, REU EN MAU Myrtaceae Eugenia pyxidata (J.Guého & A.J.Scott) N.Snow S VR MAU MAU Myrtaceae Eugenia psidioidea (J.Guého & A.J.Scott) N.Snow S VR MAU MAU Myrtaceae Psiloxylon mauritianum (Bouton ex Hook. f.) Baillon T VR MAU, REU EN MAU Myrtaceae Syzygium contractum (Poir.) J.Guého & A.J.Scott T VR MAU MAU Myrtaceae Syzygium mauritianum Guého et A.J.Scott T VR MAU MAU Ochnaceae Ochna mauritiana Lam. S VR MAU LC MAU Orchidaceae Angraecum calceolus Thouars H R I NE MAU Orchidaceae Angraecum pectinatum Thouars H R I NE MAU Orchidaceae Polystachya concreta (Jacq.) Garay & H. R. Sweet H R I NE MAU Orchidaceae Disperis oppositifolia Sm. H R I NE MAU Orchidaceae Angraecum mauritianum Frapp. H R I NE MAU Phyllanthaceae Phyllanthus phillyreifolius Poiret var. commersonii Muell. Arg. S VR MAU R MAU Pittosporaceae Pittosporum senacia Putt. subsp. senacia S VR I LC MAU Poaceae Isachne mauritiana Kunth. H R NE MAU Poaceae Oplismenus hirtellus Beauv. H O I NE MAU Poaceae Brachiaria umbellata H C I NE MAU Ranunculaceae Clematis mauritiana Lam. L VR I LC MAU Rhamnaceae Scutia myrtina (Burm. f.) Kurz L R I LC MAU Rousseaceae Roussea simplex Sm. L VR MAU CR MAU Rubiaceae Danais fragrans (Lam.) Pers. L VR MAU, REU LC MAU Rubiaceae Mussaenda arcuata Poiret L VR I VU MAU Rubiaceae Antirhea borbonica J. Gmelin S VR MAU, REU EN MAU Rubiaceae Bremeria landia (Poir.) Razafimandimbison & Alejandro T VR MAU, REU EN MAU Rubiaceae Ixora vaughanii (Verdc.) Mouly & B. Bremer S VR MAU CR MAU Sapindaceae Doratoxylon apetalum (Poir.) Radlk. var. diphyllum (Cordem.) Friedmann S R I LC MAU Smilacaceae Smilax anceps Willd. L VR I LC MAU Stilbaceae Nuxia verticillata Lam. T R MAU, REU LC MAU Urticaceae Elatostema fagifolium (Poiret) Brongn. H R MAU, REU LC MAU Urticaceae Pilea sp H R MAU Xanthorrhoeaceae Dianella ensifolia (L.) DC. S R I LC criteriaiucn

5 Cahiers scientifiques de l'océan Indien occidental 4, 2013 : Table 2. List of native and undetermined pteridophytes from Mount Bar Le Duc Crater. Status: (C) Common (individuals > 50), (O) Occasional (50 < individuals >10), (R) Rare (5< individulas < 10) and (VR) Very Rare (individuals < 5). Origin: Cryptogenic (C), Indigenous (I), Endemic to Mauritius (MAU), Endemic to Mauritius and Réunion (MAU, REU), Mascarenes (MAS) and Undetermined (U) Barecod e no. Family Taxa formlife Statut at Mt B. le Duc Origin MAU Blechnaceae Blechnum attenuatum (Sw.) Mett. var attenuatum H O I MAU Cyatheaceae Cyathea borbonica Desv. var. latifolia (Hook.) Bonap. H VR MAU MAU Davalliaceae Davallia repens (L.f.) Diels H R I MAU Dryopteridaceae Ctenitis pauciflora (Kaulf.) Holttum H O MAU MAU Hymenophyllaceae Crepidomanes bipunctatum (Poir.) Copel. H R I MAU Hymenophyllaceae Abrodictyum sp H VR MAU Hymenophyllaceae Didymoglossum cuspidatum Ebihara & Dubuisson H C I MAU Hymenophyllaceae Hymenophyllum inaequale (Poir.) Desv. H C I MAU Lomariopsidaceae Nephrolepis cordifolia (L.) C. Presl. var cordifolia H C I MAU Lomariopsidaceae Nephrolepis biserrata (Sw.) Schott H O I MAU Marattiaceae Marattia fraxinea Sm. H R I MAU Polypodiaceae Belvisia spicata (L.f.) Mirbel H R I MAU Psilotaceae Psilotum nudum (L.) P. Beauv. H R I MAU Pteridaceae Adiantum hispidulum Sw. H R I MAU Pteridaceae Antrophyum immersum (Bory ex. Willd) Matt. H R I MAU Pteridaceae Ochropteris pallens (Sw.) Sm. H VR I MAU Selaginellaceae Selaginella fruticulosa (Bory ex Willd.) Spring H O MAU, REU MAU Thelypteridaceae Cyclosorus unitus (L.) Holttum H C I MAU Thelypteridaceae Cyclosorus pulcher (Bory ex Willd.) Holttum H R I MAU Thelypteridaceae Cyclosorus hispidulus (Decne.) Ching H R I Table 3. List of alien species from Mount Bar Le Duc Crater Family Taxa Anacardiaceae Schinus terebinthifolius Raddi Arecaceae Livistona chinensis (Jacq.) R. Br ex Mart. Asteraceae Ageratum conyzoides L. Asteraceae Mikania micrantha Kunth Boraginaceae Cordia curassavica (Jacq.) Roem. et Schult. Bromeliaceae Ananas bracteatus (Lindl.) Schultes Cyatheaceae Cyathea cooperi (F. Muell.) Domin Cyperaceae Killinga bulbosa P. Beauv. Lamiaceae Lantana camara L. Lauraceae Litsea monopetala (Roxb.) Pers. Lygodiaceae Lygodium microphyllum Malpighiaceae Hiptage benghalensis (L.) Kurz Melastomataceae Clidemia hirta D. Don. Melastomataceae Ossaea marginata (Desr.) Triana Myrtaceae Psidium cattleianum Sabine Myrtaceae Syzygium jambos (L.) Alston. Myrtaceae Eucalyptus robusta J.E. Smith Oleaceae Ligustrum robustum Blume var. walkeri (Decaisne) Mansf. Orchidaceae Phaius tankervillae Blume Pinaceae Pinus elliotti Engelm. Poaceae Paspalum paniculatum L. Primulaceae Ardisia elliptica Thunb. Primulaceae Ardisia crenata Sims Primulaceae Ardisia aff. solanacea Roxb. Rhamnaceae Rhamnus nepalensis (Wall.) Laws Rubiaceae Oldenlandia corymbosa L. var. caespitosa (Benth.) Verdc. Strelitziaceae Ravenala madagascariensis Sonnerat Theaceae Camellia sinensis (L.) O. Kuntze

6 20 Flora diversity of a volcanic crater, Mauritius K. PYNEE, J.-Y. DUBUISSON & S. HENNEQUIN REFERENCES BOSSER J., CADET T., GUÉHO J. & W. MARAIS, 1976-onwards. Flore des Mascareignes - La Réunion, Maurice, Rodrigues. Institut de Recherche pour le Développement, Paris; Mauritius Sugar Industry Research Institute, Ile Maurice ; The Royal Botanic Gardens, Kew. BOSSER J., Les Graminées des Paturages et des Cultures à Madagascar. Mémoires ORSTOM (IRD), Paris. 35: 440 p. CHEKE A. & HUME J., Lost Land of the Dodo, An Ecological History of Mauritius, Reunion and Rodrigues. T & AD Poyser, London. DUKER L. & BORRE L., Biodiversity Conservation of the World s Lakes: A Preliminary Framework for Identifying Priorities. LakeNet Secretariat, Monitor International, Annapolis, USA. IUCN, IUCN Red List Categories and Criteria. Version 3.1. Gland, Switzerland. SADDUL P., Mauritius: A Geomorphographical Analysis. First Edition. Mahatma Gandhi Press. Mauritius. VAN DER PLAS G.W., DE BOER E.J., HOOGHIEMSTRA H., FLORENS F.B.V., BAIDER C. & J. VAN DER PLICHT, Mauritius since the last glacial: environmental and climatic reconstruction of the last years from Kanaka Crater. Journal of Quaternary Science, 27 (2) : DOI: /jqs.1526 WALTER K.S. & H. J. GILLETT, [eds], IUCN Red List of Threatened Plants. Compiled by the World Conservation Monitoring Centre. IUCN The World Conservation Union, Gland, Switzerland and Cambridge, UK. 1xiv + 862p. WILLAIME P., Carte pédologique de l Ile Maurice 1/ Occ. Pap. Maurit. Sug. Ind. Res. Inst., 33