edited by Philippe Bouchet, Hervé Le Guyader, Olivier Pascal PATRIMOINES NATURELS The Natural History of Santo PUBLICATIONS SCIENTIFIQUES DU MUSÉUM IRD ÉDITIONS PRO-NATURA INTERNATIONAL The Santo 2006 expedition was organized, with the support, among others, of and Représentation de l'Union Européenne au Vanuatu The Natural History of Santo edited by Philippe Bouchet, Hervé Le Guyader & Olivier Pascal Contents Foreword by Edward Natapei, Prime Minister of Vanuatu ...................................... 10 Introduction. The Natural History of Santo: An Attempt to Bridge the Gap between Academic Research and Consevation and Education .......................... 11 Vanuatu in the South Pacific ............................................................................................................. 13 Benoît Antheaume ESPIRITU SANTO IN SPACE AND TIME ........................................................................................... 17 coordinated by Bruno Corbara The Late Quaternaty Reefs ............................................................................................................................. 19 Guy Cabioch & Frederick W. Taylor The Holocene and Pleistocene Marine Faunas Reconsidered ................................. 25 Pierre Lozouet, Alan Beu, Philippe Maestrati, Rufino Pineda & Jean-Louis Reyss Geography of Santo and of the Sanma Province ............................................................... 34 Patricia Siméoni Drainage, Hydrology and Fluvial Geomorphology ............................................................. 46 James P. Terry The Climate of Santo ............................................................................................................................................................. 52 James P. Terry Large-scale Climatic and Oceanic Conditions around Santo ............................................................... 57 Christophe Maes & David Varillon A Brief History of Biodiversity Exploration and Scientific Expeditions on and off the Island of Santo ...................................................................................................................................... 62 Bruno Corbara & Bertrand Richer de Forges Deforestation on Santo and Logging Operations .......................................................................................... 67 Rufino Pineda The Impact of WWII on Infrastructures and Landscape .......................................................................... 69 Laurent Palka & Rufino Pineda Conservation Efforts in Santo ........................................................................................................................................ 71 Samson Vilvil-Fare VEGETATION AND FLORA ..................................................................................................................................................... 73 coordinated by Jérôme Munzinger & Porter P. Lowry II Exploration by the Santo 2006 Botany Team .................................................................................................... 75 Porter P. Lowry II & Jérôme Munzinger Principal Types of Vegetation Occuring on Santo ......................................................................................... 76 Jérôme Munzinger, Porter P. Lowry II & Jean-Noël Labat Phytogeographic Relationships ......................................................................................................................................... 77 Gordon McPherson How Old are the Kauri (Agathis microphylla) Trees? .............................................................................................. 83 Jonathan Palmer The Flora of Santo .................................................................................................................................................................... 89 Some New, Characteristic or Remarkable Species ......................................................................................... 89 Gordon McPherson & Jérôme Munzinger Focus on Araliaceae: Several Genera Exemplify Santo's Melanesian Biogeographic Relations ........................................ 90 Porter P. Lowry II & Gregory M. Plunkett Focus on Geissois (Cunoniaceae): Another Example of the Melanesian Connection ........................................................................................... 93 Yohan Pillon Focus on Pandans ............................................................................................................................................................... 94 Thomas Haevermans Focus on Orchids ................................................................................................................................................................. 97 Marc Pignal 5 ... Contents ....... Focus on Palms ..................................................................................................................................................................... 102 Jean-Michel Dupuyoo Focus on Ferns ...................................................................................................................................................................... 105 Germinal Rouhan Focus on Bryophytes ......................................................................................................................................................... 110 Elizabeth A. Brown Fungi, the Forgotten Kingdom ....................................................................................................................................... 113 Bart Buyck TERRESTRIAL FAUNA .............................................................................................................................................................. 117 coordinated by Bruno Corbara IBISCA-Santo Biodiversity Along an Altitudinal Gradient ...................................................................... 119 Bruno Corbara on behalf of the IBISCA network Insects on Santo ........................................................................................................................................................................ 123 Focus on Orthoptera .......................................................................................................................................................... 123 Laure Desutter-Grandcolas, Sylvain Hugel & Tony Robillard Termites in Santo: Lessons from a Survey in the Penaoru Area ............................................................ 128 Yves Roisin, Bruno Corbara, Thibaut Delsinne, Jérôme Orivel & Maurice Leponce Focus on Bees and Wasps .............................................................................................................................................. 131 Claire Villemant Myrmecophily in Santo: A Canopy Ant-Plant and its Expected and Less Expected Inhabitants 143 Bruno Corbara Beetles in Saratsi Range, Santo .................................................................................................................................. 146 Alexey K. Tishechkin, Jürgen Schmidl Lepidoptera in Vanuatu: Fauna, Geography and the IBISCA-Santo Project .................................... 155 Roger L. Kitching Other Invertebrates ................................................................................................................................................................. 161 Diversity of Spiders ............................................................................................................................................................ 161 Christine Rollard Some Arthropods as Expressed in the Words of Penaoru Villagers .................................................... 167 Bruno Corbara Indigenous Land Snails .................................................................................................................................................... 169 Benoît Fontaine, Olivier Gargominy & Vincent Prié The Vertebrates of Santo .................................................................................................................................................... 179 Terrestrial Bird Communities ....................................................................................................................................... 179 Nicolas Barré, Thibaut Delsinne & Benoït Fontaine Amphibians and Reptiles ............................................................................................................................................... 187 Ivan Ineich RIVERS AND OTHER FRESHWATER HABITATS ..................................................................................................... 237 coordinated by Philippe Keith Freshwater Habitat Types ................................................................................................................................................. 239 Philippe Keith & Clara Lord Freshwater Biota ...................................................................................................................................................................... 242 Focus on Fish, Shrimps and Crabs .......................................................................................................................... 242 Philippe Keith, Clara Lord, Philippe Gerbeaux & Donna Kalfatak Focus on Aquatic Insects ............................................................................................................................................... 251 Arnold H. Staniczek Focus on Freshwater Snails .......................................................................................................................................... 257 Yasunori Kano, Elen E. Strong, Benoît Fontaine, Olivier Gargominy, Matthias Glaubrecht & Philippe Bouchet ... 6 ....... The Natural History of Santo CAVES AND SOILS ...................................................................................................................................................................... 265 coordinated by Louis Deharveng The Karst Team .......................................................................................................................................................................... 267 Louis Deharveng & Anne-Marie Sémah Karst and Caves ......................................................................................................................................................................... 269 Bernard Lips, Franck Bréhier, Denis Wirrmann, Nadir Lasson, Stefan Eberhard, Josiane Lips & Louis Deharveng Caves as Archives ..................................................................................................................................................................... 278 Denis Wirrmann, Jean-Christophe Galipaud, Anne-Marie Sémah & Tonyo Alcover, Ni-Vanuatu Perception and Attitudes Vis-à-Vis the Karstic Environment ................................ 284 Florence Brunois Karst Habitats of Santo ...................................................................................................................................................... 288 Focus on Soils ...................................................................................................................................................................... 288 Anne Bedos, Vincent Prié & Louis Deharveng Focus on Cave Terrestrial Habitats ........................................................................................................................... 296 Louis Deharveng, Anne Bedos, Vincent Prié & Éric Queinnec Focus on Guano .................................................................................................................................................................. 300 Louis Deharveng, Josiane Lips & Cahyo Rahmadi Focus on Blue Holes ......................................................................................................................................................... 306 Stefan Eberhard, Nadir Lasson & Franck Bréhier Focus on the Loren Cave ................................................................................................................................................ 310 Franck Bréhier, Sephan Eberhard & Nadir Lasson Focus on Anchialine Fauna ........................................................................................................................................... 312 Geoff Boxshall & Damià Jaume Karst Biota of Santo ............................................................................................................................................................... 316 Focus on Bats ........................................................................................................................................................................ 316 Vincent Prié Fish and Shrimps of Santo Karstic Systems ...................................................................................................... 323 Marc Pouilly & Philippe Keith Focus on Springtails .......................................................................................................................................................... 327 Louis Deharveng & Anne Bedos Focus on Microcrustaceans ......................................................................................................................................... 331 Damià Jaume, Geoff Boxshall & Eric Queinnec MARINE ECOSYSTEMS ........................................................................................................................................................... 335 coordinated by Philippe Bouchet Benthic Algal and Seagrass Communities from Santo Island in Relation to Habitat Diversity ........................................................................................................................................ 337 Claude E. Payri The Position of Santo in Relation to the Centre of Maximum Marine Biodiversity (the Coral Triangle) .................................................................................................................................. 369 Bert W. Hoeksema & Adriaan Gittenberger Focus on Selected (Micro)Habitats .......................................................................................................................... 373 Sulfide Rich Environments ............................................................................................................................................. 373 Yasunori Kano & Takuma Haga Marine Interstitial ................................................................................................................................................................ 375 Timea Neuser Mangroves Environments of South East Santo ................................................................................................. 377 Jean-Claude Plaziat & Pierre Lozouet Focus on Selected Biota ..................................................................................................................................................... 383 Checklist of the Fishes ..................................................................................................................................................... 383 Ronald Fricke, John L. Earle, Richard L. Pyle & Bernard Séret 7 ... Contents ....... Unusual and Spectacular Crustaceans ................................................................................................................... 410 Tim-Yam Chan, Masako Mitsuhashi, Charles H.J.M. Fransen, Régis Cleva, Swee Hee Tan, Jose Christopher Mendoza, Marivene Manuel-Santos & Peter K.L. Ng The Marine Molluscs of Santo ..................................................................................................................................... 421 Philippe Bouchet, Virginie Héros, Pierre Lozouet, Philippe Maestrati & Rudo von Cosel A Rapid Assessment of the Marine Molluscs of Southeastern Santo ................................................ 431 Fred E. Wells Molluscs on Biogenic Substrates ................................................................................................................................ 438 Anders Warén Marine Partnerships in Santo's Reef Environments: Parasites, Commensals and Other Organisms that Live in Close Association ............................. 449 Stefano Schiaparelli, Charles Fransen & Marco Oliverio Seaslugs: The Underwater Jewels of Santo ......................................................................................................... 458 Yolanda E. Camacho & Marta Pola MAN AND NATURE .................................................................................................................................................................. 465 coordinated by Michel Pascal Pre-European Times .............................................................................................................................................................. 467 Vertebrate Pre-Human Fauna of Santo: What Can we Expect to Find? .............................................. 467 Joseph Antoni Alcover The Prehistory of Santo .................................................................................................................................................. 469 Jean-Christophe Galipaud Introduced Biota ........................................................................................................................................................................ 476 Overview: Introduced Species, the "Good", the "Worrisome" and the "Bad" ................................. 476 Michel Pascal, Olivier Lorvelec, Nicolas Barré, Michel de Garine-Wichatitsky & Marc Pignal Focus on Synanthropic Mammals ............................................................................................................................ 480 Olivier Lorvelec & Michel Pascal Focus on Feral Mammals ............................................................................................................................................... 483 Michel de Garine-Wichatitsky & Anthony Harry Focus on Alien Birds ........................................................................................................................................................ 488 Nicolas Barré Focus on Introduced Amphibians and Reptiles .............................................................................................. 490 Olivier Lorvelec & Michel Pascal Focus on Introduced Fish .............................................................................................................................................. 494 Philippe Keith, Clara Lord, Donna Kalfatak & Philippe Gerbeaux Focus on Alien Land Snails .......................................................................................................................................... 495 Olivier Gargominy, Benoît Fontaine & Vincent Prié Endemic, Native, Alien or Cryptogenic? The Controversy of Santo Darkling Beetles (Insecta: Coleoptera: Tenebrionidae) .................. 500 Laurent Soldati The Case of Two Invasive Species: Mikania micrantha and Merremia peltata ........................ 503 Marc Pignal Man Santo in his Environment ..................................................................................................................................... 508 Food-Garden Biodiversity in Vanuatu ................................................................................................................... 508 Sara Muller, Vincent Lebot & Annie Walter At the Junction of Biological Cycles and Custom: the Night of the Palolo .................................... 515 Laurent Palka Ni-Vanuatu Perceptions and Attitudes Vis-à-Vis Biodiversité ................................................................. 516 Florence Brunois & Marine Robillard THE SANTO 2006 EXPEDITION ........................................................................................................................................ 523 The Santo 2006 Expedition from an Ethnologist's Point of View ...................................................... 525 Elsa Faugère ... 8 ....... The Natural History of Santo The "Making of" Santo 2006 ............................................................................................................................................ 529 Philippe Bouchet, Hervé Le Guyader, Olivier Pascal Santo 2006 Expedition in the Classroom .............................................................................................................. 549 Sophie Pons & Alain Pothet Santo 2006 Expedition Participants List ................................................................................................................ 550 Acknowledgements ................................................................................................................................................................. 553 Bibliography .................................................................................................................................................................................... 557 Addresses of the Authors .................................................................................................................................................... 564 9 ... in BOUCHET P., LE GUYADER H. & PASCAL O. (Eds), The Natural History of Santo. MNHN, Paris; IRD, Marseille; PNI, Paris. 572 p. (Patrimoines naturels; 70). INDIGENOUS LAND SNAILS Benoît Fontaine, Olivier Gargominy & Vincent Prié Vanuatu is one of the Pacific countries where the terrestrial malacofauna has received most attention, with works by Alan Solem, published in 1959-1962, that remain the standard reference on the land snails of Vanuatu. A. Solem (who actually never visited Vanuatu himself), compiled and revisited all the previous literature and added results of his own studies of museum collections. As a result, 59 indigenous or cryptogenic land snails species are known from Santo (a cryptogenic species is defined as a species whose status — indigenous or introduced — is undecided), including seven which are restricted to the neighbouring islands of Malo and Aore. Most species reviewed by A. Solem had been collected from the southeastern part of the island, which is the most impacted by agriculture. A handful of species originated from the Tabwemasana range, but almost nothing was known of the mountainous and forested areas of the island (particularly the northern half of Cape Cumberland). Solem's work updated the somewhat poor knowledge on some groups. Indeed, species are often described twice or even more by researchers who are not aware of previous descriptions: as a result, several names will turn out to represent a synonym only. The genus Partula for instance was given as having 12 species in Santo. According to Solem, five only are valid, and there might be even fewer true biological species. On the other hand, our own sampling revealed species new to science, and several new records for the island. … Fauna characteristics Although land snails are famous for their slow motion, some of them have succeeded in reaching the most remote islands by passive dispersal (rafts torn off by hurricanes and migratory birds are hypothetized as possible dispersal agents). The isolation and further evolution of these species, once anchored in a new island, results in a real taxonomic signature. Usually, the more isolated the island is, the highest the level of endemism is. Santo is part of a large archipelago, with several neighbouring islands; the level of endemism of Santo itself (26 species, i.e. 44 %) is thus not as high as in more remote islands, although 41 species (69 %) are endemic to Vanuatu. The island malacofauna has three Vanuatu endemic supraspecific taxa: the genera Diplomorpha, Pseudosesara and Reticharopa, representing six species. Ogasawara Hawaii Guam Palau Seychelles Solomons Vanuatu WallisSamoa Mauritius Réunion New Caledonia Marquesas Tahiti Helicinidae Partulidae Athoracophoridae Trochomorphidae Draparnaudiidae Figure 195: Range of selected indigenous molluscan families found in Santo. Beside large range families (such as Helicinidae), the fauna is at the crossroad of several influences: Polynesian (such as Partulidae), southwestern Pacific (Athoracophoridae), Asiatic (such as Trochomorphidae), New Caledonian (Draparnaudiidae). 169 ... Terrestrial Fauna ....... Figure 196: Cryptogenic species of Pacific Islands, including Santo. A: Gastrocopta pediculus (Gastrocoptidae), Linua, Torres Islands. B: Gastrocopta pediculus (Gastrocoptidae), Matantas, Santo, h = 2.5 mm. C: Coneuplecta microconus (Euconulidae), Matantas, Santo, h = 2.8 mm. D: Coneuplecta microconus (Euconulidae), Sakao Island, Santo. E: Lamellidea pusilla (Achatinellidae), Matantas, Santo, h = 3.0 mm. F: Elasmias apertum (Achatinellidae), Tegua, Torres Islands, with one brooded juvenile visible inside the last whorl. G: Elasmias apertum (Achatinellidae), Matantas, Santo, h = 2.15 mm. H: Liardetia cf. discordiae (Euconulidae), Matantas, Santo, h = 2.15mm. I: Liardetia cf. discordiae (Euconulidae), Butmas, Santo. (Scale bar: 1 mm, x12). As a result of several colonizing events, the land snail fauna of Vanuatu in general, and Santo in particular, exhibits an interesting mixture of influences from various regions (Fig. 195): • Western Pacific Islands (particularly Papua New Guinea and Solomons) and more broadly, Asia: families Trochomorphidae, Rhytididae and some genera among Euconulidae; • Australia, New Zealand and New Caledonia: Placostylidae, Athoracophoridae, Draparnaudiidae; • Eastern Pacific (Polynesia): Partulidae, Charopidae, Endodontidae and some genera among Euconulidae and Assimineidae. These three components form relatively equal portions of the fauna. To this clearly indigenous fauna must be added seven broad-range cryptogenic species (Fig. 196). Endemism within islands exists in Santo. Although some species can be found everywhere, others show a limited range. These range restrictions can result of geology (Gonatoraphe fornicata, very abundant on limestone, is completely absent from the western — volcanic — part of the island) or altitude (one species of Pythia and another belonging to Euconulidae were only found in the Butmas uplands, Pseudosesara tabwemasanana is restricted to the Tabwemasana summit). A striking characteristic of the mollusc fauna in Santo is its poverty in high altitude cloud forests, both in terms of species diversity and of individual abundances. In such habitats above 1 000 m a.s.l., a search by two persons during one hour would typically yield one to three species each represented by one or two individuals, which is very poor compared to other Pacific volcanic islands. . . . 170 ....... Considering the number of already known species and the species found during Santo 2006 which had not been recorded before (a dozen species), it is probable that more than 80 species should be expected on the island. Alpha diversity (the number of species in a given area) seems to be similar to New Caledonia but lower than in the Solomons: in Santo, a rich station on limestone would yield 20-25 species, or 15-20 species in forest on volcanic soil (vs 30-40 in the Solomons). … Conservation During the 2006 expedition, c. 30 indigenous species were found alive, but knowledge on the native fauna is too scarce to assess the conservation status of each single species. In the Cumberland range, the degradation of the forest by introduced plants might be a source of trouble for species living at low altitude. In the eastern and southern parts of the island, the habitat has been deeply modified for agriculture (cattle and coconut plantations), and the fauna has probably been impacted. However, in these areas, there are still many limestone outcrops covered with vegetation that harbour a rich indigenous mollusc fauna, and act as refugium for limestone-dwelling snails. One family seems to have disappeared from Santo, the Partulidae: we did not find a single Partula shell, and a survey in villages in Santo and neighbouring islands, showing partulid shells to inhabitants, revealed that they do not know these species, whereas they are well aware of Placostylidae. These extinctions might be linked to the introduction of Euglandina rosea, which is well-known for its devastating impact on partulids and achatinellids in Polynesia (see "Focus on alien land snails" in section "Man and nature"). … Collecting A visitor familiar with faunas of temperate regions coming to Santo would immediately be struck by the numerous arboreal snails he would find in the forest. Indeed, the Santo fauna, as in most tropical areas, is characterized by families being partly or completely arboreal (Assimineidae, Helicinidae, Placostylidae, Partulidae). They favour trees with large and smooth leaves, and are often found on the underside of the leaves, probably as a protection against predators and heavy rains. Other species may live on the floor, in the soil, under rotten leaves, on rocks or on grass in wet places. Population density and species diversity are usually higher on limestone. However, the local abundance of species depends greatly on microhabitats: damp, hidden places at the base of rocks or trees are often much richer than flat ground a few meters away. For sampling, once a good habitat and microhabitat have been found, the main problem that should be overcome is the size of these animals: 171 The Natural History of Santo most snail species are minute (less than 5 mm when adult), brownish, and finding them by eye is not easy. Sieving the leaf litter is the solution. The first sieving is done in the field, with a 1 cm mesh Winkler sieve where litter that has accumulated in depressions, below rocks or between buttresses is processed. The fine fraction is stored to be processed later: after having been dried, the leaf litter is sieved once more through several mesh sizes, down to 0.66 mm. The dust which passes through the smaller sieve is discarded, and the remaining fractions are thoroughly searched for snails, with the help of a stereomicroscope for the smaller ones. This allows getting small species in abundance, together with rare species. However, collecting by hand-picking in the field is still necessary, for several reasons: • large species are usually not very abundant, and will not be found in the sieving • for arboreal species, only empty shells are found in the leaf-litter • as the leaf-litter has to be dried before sieving, the snails are dead by the time they are extracted. For these reasons, it is necessary to spend at least one hour on a station to look for live specimens, to take pictures, get an idea of their habits and collect live specimens for anatomical and molecular studies. Litter collecting can be standardized by sampling a standard amount of litter. This allows to assess the relative abundance of snail species and thus characterize communities in different habitats. During Santo 2006, sampling was done by all these methods (hand picking, standardized and non-standardized litter sieving). Altogether, 96 stations were sampled, including 25 in the most anthropized area (eastern and southern parts of the island), 23 above 500 m a.s.l. (Cumberland, Butmas) including four above 1 000 m a.s.l., and 60 on limestone. … Family accounts Land snail faunas comprise two basic types of snails: those with an operculum (a horny or calcareous plate situated on the tail of the body, which closes the aperture when the animal retracts into the shell), which have the eyes at the base of the tentacles; and those which lack an operculum and have their eyes at the tip of the tentacles. The families occurring in Santo are briefly presented below: Families with operculum: • Assimineidae (Figs 197G & 197H) The family Assimineidae comprises species smaller than 10 mm, with a shell predominantly conical. Three species are known from Santo, two arboreal, the other one living on the forest floor. They can be very abundant, especially in disturbed ecosystems ••• ... Terrestrial Fauna ....... Figure 197: Operculate land snail species of Santo. A: Sturanya cf. albescens (Helicinidae), Piarao, Santo. B: Sturanya cf. albescens (Helicinidae), Sakao Island, Santo, d = 6.2 mm. C: Pupina brazieri (Pupinidae), Butmas, Santo. D: Pupina brazieri (Pupinidae) (Holotype), Erromanga, h = 5.7 mm. E: Sturanya sublaevigata (Helicinidae), Sakao Island, Santo, d = 7.2 mm. F: Sturanya cf. sublaevigata (Helicinidae), W Luganville, Santo. G: Omphalotropis conella (Assimineidae), Sakao Island, Santo, h = 5.5 mm. H: Omphalotropis poecila (Assimineidae), W Luganville, Santo. I: Gonatoraphe fornicata (Poteriidae), Butmas, Santo, d = 8.4 mm. J: Gonatoraphe fornicata (Poteriidae), Sakao Island, Santo. Note the operculum on the tail. (Scale bar: 5 mm, x8). . . . 172 ....... The Natural History of Santo Figure 198: Small to minute land snails of Santo. A: Nesopupa sp. (Vertiginidae), Sakao Island, Santo. B: Nesopupa sp. (Vertiginidae), Sakao Island, Santo, h = 1.8 mm. C: Palaina sykesi (Diplommatinidae), left: probably a female, h = 4.0 mm; right: probably a male, h = 3.3 mm, Matantas, Santo. D: Palaina sykesi (Diplommatinidae), Matantas, Santo. E: Reticharopa sp.1 (Endodontidae), Matantas, Santo. F: Reticharopa sp.2 (Endodontidae), Matantas, Santo, d = 2.8 mm. G: Reticharopa latecosta (Endodontidae), Matantas, Santo, d = 2.0 mm. H: Reticharopa sp.3 (Endodontidae), Port Olry, Santo, d = 2.0 mm. I: Phrixgnathus glissoni (Endodontidae), Port Olry, Santo, d = 4.3 mm. J: Phrixgnathus n.sp. (Endodontidae), Port Olry, Santo, d = 4.4 mm. K: Phrixgnathus n.sp. (Endodontidae), Butmas, Santo. (Scale bar: 1 mm, x12). where they represent up to 75 % of the shells in standardized samples. • Diplommatinidae (Figs 198C & 198D) Diplommatinids are small to minute snails, with an ornamented shell. In Santo, two species are known. They have a ribbed shell, and have the unusual characteristic of being left-handed: when viewed from the front, the aperture is on the left (in most snail species, it is on the right). They are ground-dwelling species. In both species, shells are distributed in two size class: it is 173 believed that this represents sexual dimorphism, the larger shells probably belonging to females. They are more common in undisturbed forests, where they account for 20-60 % of shells in standardized samples. • Helicinidae (Figs 197A, 197B, 197E & 197F) Species belonging to this family share shell characteristics that render them immediately recognizable: a little less than 1 cm in diameter, they are usually dome-shaped, the suture between whorls is poorly marked, and the umbilicus (axis hole at the base of ... Terrestrial Fauna ....... the shell) is hidden by a heavy callus. They are often brightly colored, pink, yellow or brown, sometimes with darker spiral bands. However, if identifying a snail as a helicinid is easy, the lack of sculpture on the shell and the variability of color patterns make species discrimination very difficult without dissection. Two species are arboreal. They are among the most obvious indigenous land snails in Santo, though they are less abundant than smaller, less visible species. • Hydrocenidae If it was not for their vivid orange color, these tiny (less than 2 mm long) land snails would be almost impossible to find by eye on the rocks and dead leaves where they live. However, they can be amazingly abundant in sieved leaf-litter, especially in humid environment (up to 50 % of the shells collected in standardized samples). They where unknown from Santo prior to the 2006 Expedition. • Poteriidae (Figs 197I & 197J) In Santo, the only member of this family, Gonatoraphe fornicata, is unmistakable with its large size (c. 1 cm in diameter), flattened shell and round aperture. It is only found in limestone areas, where it can be very abundant. It is a rock and ground dweller. • Pupinidae (Figs 197C & 197D) The ovoid, smooth and glossy shell of Pupina brazieri, the only member of this family in Santo, is remarkable and unmistakable. A soil-dweller, this small (5-7 mm long) species is often found in numbers in the fallen fronds of palm-trees or tree-ferns. • Truncatellidae The sole member of this family in Santo, Truncatella guerinii, has an elongated and heavily ribbed shell, which is truncated at the apex in adults (hence the family and genus names). It should be looked for in lowland areas, close to the sea. Families without operculum • Achatinellidae (Figs 196E, 196F & 196G) This family has radiated all over the Pacific Islands and reaches its maximum diversity in eastern Polynesia. In Western Pacific, the shells are minute to small, thin, conical, and more or less elongated, depending on the species, generally with teeth inside the aperture. Most are arboreal and can be found on the leaves and trunks of shrubs and trees. Both Santo species have a large range in the Pacific ocean and are typically cryptogenic species: they might have been spread all over Pacific Islands by early Melanesians and Polynesians, ••• Figure 199: Indigenous slugs (Athoracophoridae, Aneitea spp.) of Santo. A: Ground-dwelling species, Beesel Valley, Cumberland Range, Santo. B: Arboreal species, East Coast, Nanda Blue Hole, Santo. C: Athoracophoridae can be found in high density in rotten wood, Tasmate, Lalautei ridge, Santo. D: Mating, Port Olry, Dionn Island, Santo, and egg laying, Sakao Island, Santo. Note the diversity of color patterns. . . . 174 ....... The Natural History of Santo Figure 200: Succineidae, Draparnaudiidae and Rhytididae of Santo. A: Succinea kuntziana (Succineidae), Pwatmel, Santo. B: Succinea kuntziana (Succineidae), Pwatmel, Santo, h = 8.7 mm. C: Draparnaudia walkeri (Draparnaudiidae), Butmas, Santo. D: Draparnaudia walkeri (Draparnaudiidae), Beesel Valley, Cumberland Range, Santo, h = 7.9 mm. E: Ouagapia santoensis (Rhytididae), Sakao Island, Santo. F: Ouagapia santoensis (Rhytididae), Butmas, Santo, d = 5.8mm. Note the wide umbilicus. (Scale bar: 5 mm, x8). or could have reached all these places through passive dispersal without human help. • Athoracophoridae (Fig. 199) These large (6-7 cm long) slugs belong to a southwestern Pacific family, ranging from New Zealand and the Australian East coast to Papua New Guinea and New Caledonia. Some species mimic veined leaves, and their color varies from white to dark grey, ground-dwelling species being brownish. In Santo, they are abundant in many areas, even degraded, and often gather in large numbers under 175 the bark of decaying logs. Some species are arboreal, and they seem to be nocturnal, being hidden during the day and wandering on tree trunks at dark. Four species are known from Santo. • Charopidae These small ground-dwelling snails have a flat shell, usually with a sculpture of dense radial ribs, somewhat ressembling Endodontidae (Fig. 198). Due to their small size and brownish color, they are mostly found by sieving. One species only is known from Santo, but new species are expected as more material is studied. ... Terrestrial Fauna ....... • Draparnaudiidae (Figs 200C & 200D) With only one member in Santo, this family endemic to New Caledonia and Vanuatu is easily recognized, with its medium (6-8 mm long) conical left-handed shell. Draparnaudia walkeri lives on the forest floor. • Ellobiidae (Figs 201H & 201I) Ellobiidae are predominantly coastal and estuarine snails, living on the high tide mark, or just above it. In Santo, some species live on the shoreline, but a larger one lives in the lowlands and can be found several hundred meters from the sea. Another species was Figure 201: Euconulidae, Trochomorphidae and Ellobiidae of Santo. A: Dendrotrochus sp.1 (Euconulidae), Mt Voutmaru, Cumberland Range, Santo. B: Trochomorpha rubens (Trochomorphidae), Tasmate, Santo. C: Trochomorpha rubens (Trochomorphidae), Tasmate, Santo, d = 12.8 mm. D: Dendrotrochus sp.2 (Euconulidae), Beesel Valley, Cumberland Range, Santo. E: Dendrotrochus sp.2 (Euconulidae), Beesel Valley, Cumberland Range, Santo, d = 13.1 mm. F: Dendrotrochus layardi (Euconulidae), Millenium Cave, Santo, h = 12.2 mm. G: Dendrotrochus layardi (Euconulidae), Matantas, Santo. H: Pythia sp. (Ellobiidae), Sakao Island, Santo, h = 27.1 mm. I: Pythia sp. (Ellobiidae), Tegoa, Torres Islands. (Scale bar 10 mm, x3). . . . 176 ....... unexpectedly found in the Butmas upland, 600 m a.s.l and probably represents a species new for science. • Endodontidae (Figs 198E-K) Endodontidae represent a family which has undergone an important radiation in the Pacific Islands. These small (usually no more than 5 mm in diameter) snails have a flat and rounded shell, often The Natural History of Santo characterized by radial ribs. Due to their small size and dull color, they typically represent the kind of snails that can only be found in large quantity by sieving. They are strictly ground-dwellers, and easily escape snail collectors: as a result, this family is probably a reservoir of species new to science in Vanuatu. Indeed, our samplings revealed a species previously unknown to science which seems to be Figure 202: Large snails of Santo. A: Placostylus bicolor (Placostylidae), Pwatmel, Santo, h = 25.2 mm. B: Placostylus bicolor (Placostylidae), old individual, Butmas, Santo, h = 43.6 mm. C: Placostylus bicolor (Placostylidae), Beesel Valley, Cumberland Range, Santo, h = 34.4 mm. D: Diplomorpha sp.1 (Placostylidae) (terrestrial species), Tasmate, Santo, h = 34.5 mm. E: Diplomorpha sp.1 (Placostylidae) (terrestrial species), Tasmate, Santo. F: Diplomorpha delautouri (Placostylidae), Butmas, Santo, h = 23.4 mm. G: Diplomorpha delautouri (Placostylidae), Dionn Island, Port Olry, Santo. H: Diplomorpha bernieri (Placostylidae), Butmas, Santo, h = 29.1 mm. I: Partula sp. (Partulidae), Port Olry, Santo, h = 25.1 mm. Specimen from museum collections. (Scale bar 10 mm, x2). 177 ... Terrestrial Fauna ....... widespread on the island, as it was found in Butmas and Port Olry. Around ten species live in Santo, they are mostly found in undisturbed habitats. • Euconulidae (Figs 196C, 196D, 196H & 196I; Figs 201A & 201D-G) This large family exhibits a wide array of shapes, from smooth, rounded flat shells to conical and ribbed ones, with or without an angular periphery (keel). Their size ranges from small (4-5 mm diameter) to medium (1 cm diameter), some are ground-dwelling, others are arboreal. Most species have a corneous translucent shell, but some are light colored, whitish to brownish, sometimes with darker spiral bands, and an appendice is generally visible at the end of the tail. A dozen species should be expected on the island. Euconulidae are abundant in most samples, representing 10 to 60 % of collected shells in standardized samples. Some Euconulidae have a restricted range within Santo: a small species, new to science, with characteristic large radial ribs on the shell was only found near Butmas; a large (sub)species was only found on the summital ridge of the Cumberland range. • Gastrocoptidae (Figs 196A & 196B) Gastrocopta pediculus is another example of cryptogenic species. It is found all over the Pacific, usually in lowland areas, and can be very abundant on the soil in sandy coastal areas. It has a minute shell, whitish, with a toothed aperture, and is usually only found after sieving the soil and leaf-litter. • Partulidae (Fig. 202I) This Pacific Islands family has large (c. 2 cm long), elongate oval to conical shells, with the aperture often thickened. They are exclusively arboreal. They are famous for having been decimated in Eastern Polynesia, due to habitat destructions and predation by the introduced Euglandina rosea. Indeed, five species were known from Santo and neighbouring islands, but they seem to be extinct now. In Vanuatu, this family still survives at least in the Torres Islands. • Placostylidae (Figs 202A-H) In Santo, the five species of Placostylidae are the largest indigenous land snails. This Western Pacific family ranges from northern New Zealand to the Solomons and Fiji. The snails have a thick and elongated shell, and seem to be nocturnal, being hidden under stones and logs during the day. A few species are arboreal. As the shells are quite solid, they remain a long time on the ground, and can still be found in large numbers in degraded areas where no live animals are found nowadays. • Rhytididae (Figs 200E & 200F) The Rhytididae are carnivorous, feeding on other small snails or soil invertebrates. Two species belonging to the genus Ouagapia are known from Santo. They have a small flat shell and live on the forest floor. • Succineidae (Figs 200A & 200B) Succineidae have a peculiar pear-shaped fragile and reduced shell. In Santo, Succinea kuntziana is a ground-dwelling species, sometime found on the leaves and stems of low vegetation, and usually not too far from freshwater. • Trochomorphidae (Figs 201B & 201C) One species is known from Santo. It has a medium (ca. 1 cm diameter) sized dome-shaped shell, the last whorl keeled, and is often found under logs and dead wood. • Vertiginidae (Figs 198A & 198B) This family was previously unknown from Santo. Nesopupa spp. are tiny snails, with a toothed aperture, living on the bark of trees trunks and on rocks. Although rare, it was found all over the island, for instance near the village of Tasmate, on the West coast, on the island of Sakao, on the East coast, and near Matantas in Big Bay, suggesting a large distribution on the island. This shows that a widespread species can escape collecting for decades if it is minute enough. . . . 178 The Natural History of Santo The islands of the Pacific are renowned for the high levels of endemism of, and threats to, their unique faunas and floras. Espiritu Santo, affectionately known simply as Santo, is an island of superlatives: the largest and highest in Vanuatu, Santo is an extraordinary geographical and cultural microcosm, combining reefs, caves, mountains, satellite islands, and a history of human habitation going back 3 000 years. In the spirit of famous voyages of discovery of the past, the Santo 2006 expedition brought together over 150 scientists, volunteers and students originating from 25 countries. With contributions by more than 100 authors, The Natural History of Santo is a lavishly illustrated homage to the biodiversity of this "planet-island". Bridging the gap between scientific knowledge and conservation and education, The Natural History of Santo was written with local stakeholders as well as armchair naturalists from all over the world in mind. Les îles du Pacifique sont célèbres pour le très haut niveau d’endémisme et la grande vulnérabilité de leurs faunes et de leurs flores. L'île d'Espiritu Santo, ou Santo, cumule les superlatifs : la plus grande et la plus haute du Vanuatu, Santo est un extraordinaire microcosme géographique et culturel, avec récifs, grottes, montagnes, îles et îlots satellites, et une occupation humaine qui remonte à 3 000 ans. Renouant avec l'esprit des "Grandes Expéditions Naturalistes", l’expédition Santo 2006 avait mobilisé sur le terrain plus de 150 scientifiques, bénévoles et étudiants de 25 pays. Petit tour de force éditorial avec plus de 100 auteurs, ce Natural History of Santo est un éloge de la biodiversité de cette "île-planète". À la fois beau livre richement illustré et bilan des connaissances scientifiques, The Natural History of Santo se veut un outil de connaissance pour sa conservation durable. Il s'adresse autant aux acteurs locaux du développement et de l'éducation qu'aux naturalistes du monde entier. ISSN 1281-6213 ISBN MNHN : 978-2-85653-627-8 ISBN IRD : 978-2-7099-1708-7 9 782856 536278 Prix : 59฀฀TTC