7 th Int. Conference on Environmental Future : Humans & Islands, Honolulu, HAWAII (USA), 16 April 2018 (MATARAI )

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1 The invasive tree Miconia calvescens, a global threat to tropical island forest ecosystems worldwide: mapping its current and potential distribution Jean-Yves MEYER 1, Robin POUTEAU 2, Mélanie LIBEAU 3 & Ravahere TAPUTUARAI 4 1 Délégation à la Recherche, Tahiti, French Polynesia 2 Institut Agronomique Néo-Calédonien, Nouméa, New Caledonia 3 AgroParisTech, Montpellier, France 4 Association Te Rau AtiAti a Tau a Hiti Noa Tu, French Polynesia (MATARAI )

2 Native range: Tropical & Central America Miconia calvescens DC (Melastomataceae) Cyanophyllum magnificum (Rev. Hort 1859) Maria Orozco Botanical Garden, Costa Rica (S. CASTILLO )

3 Introduced ranges: Tahiti> 80,000 ha 1850 s Moorea>3,500 ha Hawai i (Big island)> 61,000 ha Maui>12,000 ha s s 1960 s North Queensland> 300 ha New Caledonia> 140 ha (P. LEARY ) (BIOSECURITY QUEENSLAND ) (E. KILLGORE )

4 A dominant plant invader in rainforests and cloudforests Miconia first introduction site Miconia current distribution 1937 Jardin botanique Harrison Smith Papeari, Tahiti (1963)

5 with direct impacts on the native and endemic flora Miconia dense monospecific forest Polyscias tahitensis (EN) Myrsine longifolia (EN) Cyrtandra spp. Ophiorrhiza spp. Calanthe tahitensis Lepinia taitensis (EN) Miconia invaded forest understory (Meyer & Florence Journal of Biogeography 23) Psychotria spp. Sclerotheca jayorum (CR)

6 and indirect impacts on forest ecosystem services Soil erosion & landslides Watersheds Fa atautia valley Lake Vaihiria Papenoo valley Urufaau pass 1982 (TNC )

7 Objective: predicting the risk of plant invasions Invasive species current and potential distribution are used for planning control efforts and evaluation success Study site: Marquesas Is.: 6 main islands, 48% endemism, 131 threatened endemic plants, 2 islands with Miconia (Nuku Hiva, Fatu Iva < 5 ha), a UNESCO World Heritage Site project

8 Method: Maximum Entropy Modeling (MaxEnt) Worldclim (version 2) for climatic variables: mean annual rainfall and temperature, precipitations of the driest month, annual wind speed ) Digital Elevation Models (DEMS) for topographic variables: elevation, slope steepness, annual solar radiation, topographic wetness index Relative importance of the 5 climatic variables used to project Miconia distribution in the Marquesas according to the origin of occurrence records used to calibrate species distribution models

9 Occurrence records > 3,000 GPS points

10 Results Equilibrium distribution of Miconia calvescens based on climate variables with the origin of occurrence records used to calibrate species distribution models. Equilibrium distribution of Miconiacalvescens based on topographic variables (Libeau et al. in revision. Pacific Science)

11 Conclusions (I) Miconia has the potential to spread over a large area of native rainforests & cloudforests in Nuku Hiva (46%) and Fatu Iva (33%) Miconia can invade the 4 other Marquesas islands (Ua Huka, Ua Pou, Hiva Oa, Tahuata) Strict biosecurity measures are urgently needed, as well as active public awareness campaigns

12 Conclusions (II) Invasive species distribution models are useful! Prevention and warning tools for decisionmakers Monitoring and field surveys (ground and aerial) for managers (P. LEARY )

13 Miconia, a global threat to tropical island forests worldwide? (S. HUDIN ) (S. HUDIN ) (S. HUDIN ) (C. DELNATTE )

14 Mauruuru roa/mahalo nui loa My three collaborators: Robin, Mélanie & Rava Brett GELINAS (Big Island Invasive Species Committee), Cleve JAVIER (Kauai Invasive Species Committee), Brooke MAHNKEN and Teya PENNIMAN (Maui Invasive Species Committee), James LEARY (University of Hawai i at Mānoa), Jean FUJIKAWA and Rachel NEVILLE (Oahu Invasive Species Committee), and Mick JEFFERY (Biosecurity Queensland, Australia) Dr. Lloyd LOOPE (USGS, Haleakala National Park, Maui) Lloyd L. LOOPE ( )