The Natural History of N Aturels

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Santo edited by Philippe Bouchet, Hervé Le Guyader, Olivier Pascal The Natural History of N aturels

Publications scientifiques du muséum IRD ÉDITIONS

Patrimoines PRO-NATURA INTERNATIONAL The Santo 2006 expedition was organized, with the support, among others, of

and

Représentation de l'Union Européenne au Vanuatu Santo edited by Philippe Bouchet, Hervé Le Guyader & Olivier Pascal The Natural History of 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

Contents 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).

Focus on blue holes Stefan Eberhard, Nadir Lasson & Franck Bréhier

Whereas the western part of Santo is characterised the underlying volcanic rocks. As often occurs on by high and steep mountains of volcanic origins, limestone terrains, most rainfall disappears under- the eastern part has a more subdued topography ground into caves and few streams flow on the with marine-deposited limestones lying on top of surface for any great distance. The underground

...306 ...... The Natural History of Santo

the coast. As it penetrates further inland, the wedge of seawater is pushed deeper beneath the freshwater lens which is thinnest near the coast and which gradually thickens further inland. Fresh groundwater flows along the hydraulic gradient towards the coast where it is forced to discharge to the surface by the underlying wedge of seawater pushing inland. Discharge of the fresh groundwater to the surface is focused at a series of points forming springs, which are sometimes formed into blue holes, and from where the water continues its course to the ocean as a stream on the surface. ……Why blue holes are "blue" As light passes through water the different wavelengths forming the visible light spectrum are absorbed at different rates. Wavelengths at the red end of the spectrum are absorbed preferentially while wavelengths at the blue end of the spectrum are least absorbed. Thus, deep clear water usually appears blue. The molecular structure of water also confers a typically blue colour, often enhanced by reflection of a blue sky. The natural blue colour exhibited by bodies of water may be altered by dissolved substances or suspended particles. On Santo, the deep spring-ponds discharge water that is crystal clear, and when there is a clear blue sky overhead, the "blue holes" are at their most spectacular. Figure 369: Location of the blue holes of Santo Island eastern coast. Red circles: caves. Blue circles: blue holes. Vatvateur and Vatvatel Blue Holes were not explored. ……The blue holes: a target for the Santo 2006 expedition karst team streams resurge at the surface near the coast, some- Four of the blue holes were mapped and sampled times into large and deep circular ponds known as for subterranean fauna by the karst team during blue holes. Blue holes occur in similar situations on the Santo 2006 expedition. These were: limestone islands in the tropics elsewhere, however • Matevulu 1 and 2; the blue holes of Santo are spectacular. The blue • "Trou Bleu du CIRAD"; holes of Santo, somewhat hidden in the jungle but • Nanda Blue Holes. still of easy access from Luganville, the main town The blue holes mapped on Santo ranged in diam- of Santo, are large and deep pools of clear water eter from 10 to 50 m, and reached up to 19 m in with a beautiful turquoise hue (Fig. 369). They depth (Figs 370, 372 & 374). At the base of the are popular with tourists for swimming, canoeing, blue holes the spring water discharges from the and diving. The blue holes are also an important sandy bottom, or small caves and fissures in the soft source of freshwater, and a habitat for many species and friable limestone. The caves cannot be entered of plants and animals, including some which are far by divers before further passage is blocked by unique to the blue holes. collapsed rocks. Entering the caves is extremely dangerous due to the risk of silt-out and collapse of ……A brief description the soft and friable rock. Cave diving should only The blue holes are actually a type of spring that be undertaken by properly trained and experienced discharges groundwater from the limestone aquifer cave divers. For most divers the caves are of little which is fed by rain falling in the hinterland catch- interest and the open water in the ponds provides ment. Most cave systems are formed by the corro- the most interesting experience with the plants and sive action of rainwater, which is naturally acidified abundant fish and animal life. by carbon dioxide from the atmosphere and soil, and that is capable of dissolving carbonate rocks Another aim of the Santo 2006 expedition was such as limestone. The portion of rainfall that is to attempt to collect aquatic subterranean fauna not lost by evaporation or transpired by plants from the blue holes which may be “washed-out” seeps underground and recharges the groundwa- from deeper aquifer habitats. In this aim we were ter aquifer. The aquifer forms a lens of less dense partially successful in collecting a new species of freshwater that "floats" on top of a "wedge" of subterranean amphipod from Nanda Blue Hole, underlying seawater that penetrates inland from however we had more success in sampling the

307 ... Caves and Soils ......

Figure 370: Topography of Nanda Blue Hole (Natawa-Santo-Vanuatu, Santo 2006 expedition). Topographical plan: N. Lasson (16/09/2006). deeper aquifer habitats by pumping from the wells which provide the villages with freshwater.

••• Nanda Blue hole With its crystal-clear water, it is one of the most striking blue holes on Santo (Figs 370 & 371). Most of the strong flow comes from a crack that opens close to the surface. It is a habitat for many species of plants, fish and invertebrates including the freshwater hermit crab, Clibanarius fonticola.

••• Matevulu blue holes 1 & 2 Matevulu is a large and deep (-19 m) pool of fresh water from which discharges a strongly flowing river that reaches the sea along a winding course. It is a very popular tourist attraction and local guides offer visitors a swim or a peaceful descent of the river. We asson L . dived and mapped this blue hole, and found a major N outflow of water in the bottom (Fig. 372). Although a passage could be observed, it was too narrow for Photo Figure 371: Diving in crystal waters of blue holes: Nanda blue further exploration. We put a net to sample fauna in hole. the outflow point of the spring, but did not capture any subterranean aquatic species.

Close by to Matevulu 1, lies Matevulu 2, which is smaller, shallower, and with no obvious spring outflow at the bottom. However, the deep blue of its water, well hidden amongst a luxurious forest, attracts many visitors (Fig. 373). Diving failed to reveal any submerged passages in this hole. ips L . B Figure 372: Topography of Matevulu 1 Blue Hole (Matevulu- Santo-Vanuatu, Santo 2006 expedition). Photo Topographical plan: N. Lasson (23/06/2006). Figure 373: Matevulu 2 blue hole.

...308 ...... The Natural History of Santo réhier Figure 374: Topography of "Trou Bleu" du CIRAD (Surunda- B Santo-Vanuatu, Santo 2006 expedition).

Topographical plan: N. Lasson (03/09/2006). Photo F. Figure 375: "CIRAD" blue hole.

••• "Trou Bleu du CIRAD" ("CIRAD" blue hole) It is 40 m in diameter but only reaches a depth of other animal populations. There is some evidence about 3 m (Figs 374 & 375). The spring outflow that eutrophication has already impacted CIRAD occurs at several points along one side of the hole, Blue Hole (Fig. 376). one of which is just large enough to be entered by trained cave divers, however the passage soon Another possible threat to the blue holes may be becomes too narrow after only a few meters. We tourism, if visitors and visitor impacts are not care- sampled for fauna inside this cave and collected fully managed and monitored. Visitor impacts may several species which had obviously originated include for example, trampling and damage to veg- from nearby surface waters. etation, disturbance of habitats and animals, pollutants (e.g. sunscreen) and rubbish. The cumulative ……Why are the blue holes important? impacts of visitors over many years may lead to grad- The blue holes on Santo are a spectacular natural ual degradation of the natural and aesthetic qualities feature popular with locals and tourists for swim- which visitors come to see, and ultimately lowering ming and diving. They are an important source the value to tourism of the blue holes. Thus, tourism of freshwater, as well as a habitat for plants and at the blue holes needs to be carefully managed and animals, including some rare and significant spe- monitored, so that future generations can continue cies such as the freshwater hermit crab, Clibanarius to appreciate and enjoy them in pristine condition. fonticola, known only from Nanda and Matevulu Blue Holes. Hence it is important to protect and conserve the blue holes from any human activity that may threaten them.

Possible threats to the blue holes include pollu- tion or eutrophication in the spring-lakes or the groundwater which feeds them. Pollutants may enter the lakes directly, or less obviously, by flow of groundwater originating in the hinterland catch- ment areas. Eutrophication is an increase in chem- ical nutrients containing nitrogen or phosphorus, which typically originate from human sources such ips L

as fertilisers, sewage, etc. Lakes subject to eutrophi- . cation typically experience excessive algal blooms, B resulting in poor water quality including lack of Photo oxygen and severe reductions or death of fish and Figure 376: Eutrophication of the CIRAD blue hole.

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