longlong--term study of forest dynamics and monitoring of ......longlong--term study of forest...

LongLong--term study of forest dynamics and monitoring of term study of forest dynamics and monitoring of the impacts of plant invasions and climate change in the impacts of plant invasions and climate change in

the islands of Tahiti and Mooreathe islands of Tahiti and Moorea(French Polynesia)(French Polynesia)

“23rd Pacific Science Congress”, Academia Sinica, Taipei, 16 June 2016

1 Délégation à la Recherche, Government of French Polynesia, Tahiti2 NGO « Te Rau Ati Ati a Tau a Hiti Noa Nu », Tahiti, French Polynesia3 Université de Montpellier 2, Montpellier, France

JeanJean--Yves MEYERYves MEYER11, Ravahere TAPUTUARAI, Ravahere TAPUTUARAI22 & Méryl JORDAN& Méryl JORDAN33

French Polynesia (South Pacific)French Polynesia (South Pacific)


4,000-8,000 BP

AD 900

1,000 BP

2,000-3,000 BP

(Trejaut et al. 2005. PLoS Biology 3(8); Soares et al. 2011. Am. J. Human Genetics 88)

?

AD 1200

AD 900

?

POLYNESIA


French Overseas Territory

EEZ = 5 million km²

120+ oceanic islands

0.3-30 M yrs old

Land area = 3,500 km² MOOREA Land area = 3,500 km²

Population (2015)= 270,000

TAHITI

BORA BORA

MOOREA

Flora of French PolynesiaFlora of French Polynesia

TotalTotal Indigenous speciesIndigenous species Endemic speciesEndemic species Endemism rateEndemism rate

Native floraNative flora 881881 335335 546546 62%62%

(Florence et al. 2007)


CultivatedCultivated NaturalizedNaturalized InvasiveInvasive

Alien floraAlien flora > 2000> 2000 > 590> 590 > 70> 70

Metrosideros collina

(native)

(Fourdrigniez & Meyer, 2008)

Cyrtandra

(25 endemic species)

Psychotria

(27 endemic species) Apetahia

(endemic genus)Fitchia

(endemic genus)

Main goals:Main goals:Study of island forest ecosystem composition, Study of island forest ecosystem composition,

structure and dynamics with local & global changesstructure and dynamics with local & global changes

�� Plant diversity and abundance Plant diversity and abundance (native (native vsvs alien species)alien species)

�� Species distribution along elevation gradients Species distribution along elevation gradients ((≠ habitat types)≠ habitat types)

�� Impacts of anthropogenic disturbances Impacts of anthropogenic disturbances (incl. invasive species) (incl. invasive species)


on forest dynamicson forest dynamics (e.g. seedling recruitment)(e.g. seedling recruitment)

�� Potential future effects of climate change Potential future effects of climate change (incl. global (incl. global warming)warming)

Mt Marau ridge (1,493 m), TahitiMiconia invaded forest, Tahiti

Native montane cloud forest, Mt Aorai, Tahiti

Other common objectivesOther common objectives

�� Comparisons between Comparisons between small high volcanicsmall high volcanic Pacific islands Pacific islands (Micronesia, Melanesia & Polynesia)(Micronesia, Melanesia & Polynesia)

�� A contribution to the A contribution to the ““PacificPacific--Asia Biodiversity Transect” Asia Biodiversity Transect” onon--goinggoing project & network (9th PSI Taipei 1998, 19th PSC Sydney project & network (9th PSI Taipei 1998, 19th PSC Sydney 1999)1999)


TAHITI island topography (Ferry, 1988) PABITRA sites (Mueller-Dombois, 1998)

Moorea study sitesMoorea study sites

�� “Col des Trois Cocotiers“Col des Trois Cocotiers--Mt Mt Mouaroa transect” Mouaroa transect” (200(200--500 m)500 m)

�� 10 sites (set up in 10 sites (set up in 2005/20062005/2006))

�� Ten Ten 20x20 m plots 20x20 m plots (divided in four (divided in four 10x10 m plots) in 10x10 m plots) in lowlow-- to midto mid--elevation rainforestselevation rainforests


Moorea (140 km², 1207 m)elevation rainforestselevation rainforests

Vaianae plot (Moorea)

Tahiti study sitesTahiti study sites

�� “Belvédère“Belvédère--Mt Aorai transect” Mt Aorai transect” (600(600--2200 m)2200 m):: 8 sites (set up in 8 sites (set up in 20132013))

�� “Mt Marau transect” “Mt Marau transect” (800(800--1100 m)1100 m):: 2 sites2 sites

�� Two Two 10x10 m 10x10 m permanent plots in gulch forestspermanent plots in gulch forests

600 m


Belvédère-Mt Aorai transect

900 m

1400 m

2,200 m 1,700 m

600 m

Tahiti (1045 km², 2241 m)

MethodMethod�� All All woody specieswoody species (native & alien) above 1.3 m tall (native & alien) above 1.3 m tall ⇒⇒ stem density stem density

(mean number/m²(mean number/m²))

�� All All DBH DBH (> 1 cm) (> 1 cm) ⇒⇒ total basal area total basal area (cm²/m²)(cm²/m²)

�� 20 quadrats (2x2 m) randomly selected in each 10x10 m plot 20 quadrats (2x2 m) randomly selected in each 10x10 m plot ⇒⇒seedling density seedling density (mean number/m²)(mean number/m²)


Slope

Edge

Environmental monitoring (microEnvironmental monitoring (micro--climate)climate)


Temperature & humidity Dataloggers (1h/2yrs)

(MagTech RHTemp 1000 in Tahiti, Hobo Pro v2 in Moorea)

ResultsResults in Tahiti: in Tahiti: forestforest compositioncomposition


Mt Aorai elevational transect (600-2000 m)

ResultsResults in Tahiti: in Tahiti: forestforest structurestructure


AOR = Mt Aorai ; MAR = Mt Marau

ResultsResults in Tahiti: in Tahiti: alienalien plant invasionsplant invasions


Aorai plot, 900 m

Miconia calvescens (Melastomataceae)

African tulip tree Spathodea campanulata (Bignoniaceae)

ResultsResults in Tahiti: in Tahiti: forestforest dynamicsdynamics


Rubus rosifolius (Rosaceae) Rhus tahitensis (Anacardiaceae)

(NATIVE) (ALIEN)

ResultsResults in Moorea: in Moorea: forestforest structurestructure


OPU = Opunohu valley ; VAI = Vaianae valley ; MOU = Mt Mouaroa

ResultsResults in Moorea: in Moorea: forestforest dynamicsdynamics


Spathodea campanulataPittosporum tahitense

(ENDEMIC) (ALIEN) (ENDEMIC) (ALIEN)

Conclusion & DiscussionConclusion & Discussion


�� High vulnerability to invasion of tropical High vulnerability to invasion of tropical rainforests at low and mid elevationrainforests at low and mid elevation (below (below 1,200 m) in Tahiti and Moorea1,200 m) in Tahiti and Moorea

�� Significant decrease of alien speciesSignificant decrease of alien speciesdiversity, stem density and seedling diversity, stem density and seedling recruitment with elevation (except for the recruitment with elevation (except for the recruitment with elevation (except for the recruitment with elevation (except for the pioneer alien pioneer alien Rubus rosifolius Rubus rosifolius !)!)

�� Low seedling recruitmentLow seedling recruitment (on the ground) (on the ground) of native woody species at high elevation of native woody species at high elevation (> 1,200 m)(> 1,200 m)

⇒⇒ Relative resilience of native Relative resilience of native island forests at high elevation?island forests at high elevation? Rubus rosifolius at Mt Tohiea

(1,200 m) in Moorea

Miconia calvescens« the green cancer »

The The potentialpotential impacts of global impacts of global warmingwarming(P

ou

teau et al.

2010)

• 14,000 ha of cloud forest & subalpine

vegetation (> 1800 m)• +1.4°C in 2050 / +3.1°C in 2100• +220 m shift in 2050 / +490 m in 2100• � to 6,500 ha in 2050 / 1,500 ha in 2100

⇒⇒ Future eFuture extinction of a unique xtinction of a unique


2010)

⇒⇒ Future eFuture extinction of a unique xtinction of a unique habitat and habitat and endemicendemic plants?plants?

Mt Orohena (2,240 m), Tahiti

Grammitis sp. nov. (Grammitidaceae)

�� First comprehensive study on vascular First comprehensive study on vascular plant diversity, abundance and plant diversity, abundance and altitudinal distribution in Tahiti and altitudinal distribution in Tahiti and


Summary & Future prospectsSummary & Future prospects

altitudinal distribution in Tahiti and altitudinal distribution in Tahiti and Moorea (“zero point”)Moorea (“zero point”)

�� Series of permanent plots set up along Series of permanent plots set up along elevation gradients in Tahiti and elevation gradients in Tahiti and Moorea (to be increased)Moorea (to be increased)

�� Ecological comparisons with other Ecological comparisons with other Pacific islands…and at a more global Pacific islands…and at a more global level !level !

The MOVECLIM ProjectThe MOVECLIM Project

�� MOntane VEgetations as listening posts for CLIMate changeMOntane VEgetations as listening posts for CLIMate change

�� “Net“Net--Biome” Biodiversity research program (2010Biome” Biodiversity research program (2010--2015)2015)

�� Sponsored by Europe (ERANET) and funded by France (ANR)Sponsored by Europe (ERANET) and funded by France (ANR)

�� First collaboration between European Overseas First collaboration between European Overseas


Island Regions & Territories: La Réunion Island Regions & Territories: La Réunion (Indian Ocean)(Indian Ocean), Guadeloupe , Guadeloupe (Caribbean Sea)(Caribbean Sea), , Tahiti Tahiti (Pacific Ocean)(Pacific Ocean), Azores & Canaries , Azores & Canaries (Atlantic Ocean)(Atlantic Ocean)

�� + South Africa, Malaysia, Germany, + South Africa, Malaysia, Germany, Switzerland, France…Switzerland, France…

�� Focus on mosses (Bryophytes) & ferns Focus on mosses (Bryophytes) & ferns (Pteridophytes)(Pteridophytes)

多謝感謝撈力

MauruuruMauruuru roaroa, merci beaucoup, , merci beaucoup, manymany thanksthanks !!


Ravahere, Julie, Marie & Robin

botanist Jacques Florence (retired in January 2016)

« Te Rau Ati Ati a Tau a Hiti Noa Tu » NGO

Pauline & Maruiti

Méryl

Marie & Julie

Base camp at 2,200 m

longlong--term study of forest dynamics and monitoring of ......longlong--term study of forest...

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