ecological research in papua new guinea: some …

ECOLOGICAL RESEARCHIN PAPUA NEW GUINEA:

Some important and interesting problems

Vojtech Novotny and collaborators

BiodiversityLandPNG

Others

What makes Papua New Guinea important and special inbiodiversity research?

- Large species richness- High level of species endemism- Low environmental destruction

Temperate forests:

low diversitywoody plants: 5 - 20 species per ha

Tropical forests:

high diversitywoody plants: 100 - 800 species per ha

Papua New Guinea:low population densitylarge forest areas

Why are there so many species in the tropical areas?

How can so many species survive at a single site?

How species influence one another in the ecosystem?

Our study:

Species-rich group - insect herbivoresand their interaction with host plant species

Parataxonomist Training Center:main station & 3 field laboratories, 1 researcher,15 parataxonomists, 3 postgraduate students,30 village assistants

Rubiaceae

Psychotria

Plant - herbivore interactions: plant species selected for the study

asterids

Ficus

Moraceae

eurosids I

Macaranga

Euphorbiaceae

eurosids II

Host specificity of fruit flies 8,000 fruit flies reared from 600 kg of fruits from 170 plant spp.

Host specificity of Cerambycidae2,500 beetles reared from 3,000 kgof timber from 10 tree spp.(ongoing study; target 40 tree spp.)

Host specificity of caterpillars60,000 caterpillars collected and20,000 reared from 90 tree species

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caterpillars cerambycids fruit flies caterpillars cerambycids fruit flies

specialists others

Congeneric hosts Allofamilial hots

Herbivores on large plant genera:low specificity with respect to congeneric hosts

Ficus 135 spp.in New Guinea(global maximum)

Large generaare prominentin tropical floras

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Caterpillar assemblages on rainforest trees:- high dominance by a single or few species- low spatial variability (across 1-25 km distances)- low seasonality

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Similarity between caterpillar communities from different hosts

A sample of 300 caterpillars per host tree is enough

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Macaranga quadriglandulosa x M. aleuritoides

Caterpillar assemblages on rainforest trees arepredictable and amenable to study

300 caterpillars per host:20 person-days of sampling60 person-days of rearing, sorting, mounting, databasing

Caterpillars from the 151 species of woody plants from1 ha of the rainforest:10 persons working for 5 years + taxonomic work

Possible studies using caterpillar assemblages on rainforesttrees as the units of analysis:

• species turnover between locally coexisting assemblages ondifferent host tree species• species turnover between assemblages on a particular tree speciesalong environmental gradients (e.g. altitudinal)• species turnover between assemblages on a particular tree species ina particular habitat on large spatial scales• species turnover between assemblages on native and invasive treespecies• etc.• etc.• etc.

1 ha of secondaryvegetation:196 woody species,including 55 species(83 % of total biomass)studied for caterpillars 1.E+00

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Plant community from 1 ha of secondary forest

Young secondary vegetation:

a synthesis of a compoundcaterpillar assemblage fromassemblages feeding onindividual tree species

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Compound caterpillar assemblage on secondary vegetation

Prominent position ofcaterpillars specialised toa single host family:

Lower dominance in the compoundassemblage compared to assemblageson individual host tree species

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Piper aduncum:• invaded 20-30 years ago• presently the most abundantspecies in secondary forests

• Abundance and species richness ofcaterpillars on Piper aduncum iscomparable to native hosts• Almost all polyphagous caterpillarsfrom native hosts quickly colonisedPiper aduncum

Caterpillars on alien vs. native hosts

Ficus wassa

Lowland rainforest 100 m asl. Montane rainforest 1,800 m asl.

Beta-diversity along an altitudinal gradient:

Caterpillars feeding on identical hosts(Ficus wassa, F. copiosa and F. dammaropsis)in lowland and montane rainforests

Field laboratory in Mu Village (1,800 m asl.):caterpillar studies along an altitudinal gradient

Species turnover in caterpillar assemblages feeding onFicus wassa, copiosa and dammaropsisalong an 1,700 m altitudinal gradient:

>90%

Asota versicolor: MONTANE & LOWLAND

Philiris sp.: MONTANE only

Euploea leucosticos: LOWLAND only

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MONTANELOWLAND

Montane & lowland caterpillarsfeeding on Ficus trees:different species recruitedfrom identical higher taxa

Beta-diversity across large expanses of lowland rainforests:is there any?

THEORETICAL ARGUMENTS:• prominent role of large plant genera in forest vegetation• low host specificity with respect to congeneric hosts• absence of dispersal barriers in the lowlands

40 % of all fruit fly species known fromNew Guinea found at a single lowland site

EMPIRICAL PATTERNS:• high local/regional ratio of species richness

Beta-diversity across large expanses of lowland rainforests:a proposed study in 900 km2 of Sepik & Ramu river basins

Target: 5,000 caterpillars from each siteTeam: 1 researcher, 4 parataxonomists,15 village assistantsTime schedule: 3 months per siteKey innovation:extensive use of assistance by local villagers

Beta diversity of caterpillars on hosts from large genera• 12 hosts from Ficus, Syzigium, Macaranga & Psychotria• local & widespread hosts included from each genus• 9 sites within a 600 x 200 km lowland area Local plant names:

Ficus wassatinamsinamtombetombeasetawidonkusakamwarasokoquanjangaletiam

Wannang Insect Laboratories Ltd.

Further information:• Web page www.entu.cas.cz/png/index.html• New book (February 2003): Basset, Y., Novotny, V., Miller, S.E. & Kitching. R.(eds.) Arthropods of Tropical Forests: Spatio-Temporal Dynamics and Resource Use inthe Canopy, Cambridge University Press, Cambridge.• Key papers - Novotny V., Basset, Y., Miller, S.E. et al. (2002):• Nature 416, 841-844• Journal of Animal Ecology 71, 400-412• Proc. Royal Society, London, Biol. Sci. 269, 2337-2344.

How to obtain additional information:visit Papua New Guinea!

Acknowledgements: parataxonomists Kenneth Molem, William Boen, John Auga, RichardKutil, Brus Isua, Markus Manumbor, Martin Mogia, Elvis Tamtiai, Max Manaono, MarkAndreas, Borenke Kaupa, Joseph Kua, Chris Dal, Roll Lilip, Martin Kasbal, Micah Damag,Samuel Hiuk, researchers Solomon Balagawi, Lawong Balun, Mark Ero, Lance Hill Jan Leps,Lukas Cizek, Pavel Drozd, Milan Janda, Jiri Hulcr, Sim Sar, Alan Stewart, Wayne Takeuchi,Roger Kitching, Karie Darrow, Kipiro Damas, funding agencies the National ScienceFoundation, Darwin Initiative, Czech Grant Agency, Packard Foundation, Otto Kinne Foundation& Papua New Guinea Biological Foundation, institutions University of Papua New Guinea,PNG University of Technology, PNG National Agriculture Research Institute, SmithsonianInstitution, Czech Academy of Sciences, University of South Bohemia, University of Minnesota,University of Sussex, Bishop Museum & Natural History Museum London.