The extended phenotype of Eucalyptus globulus B Potts 1 , R Barbour - PowerPoint PPT Presentation

The extended phenotype of Eucalyptus globulus B Potts 1 , R Barbour 1 , J O’Reilly-Wapstra 1 , S Baker 2 , L Forster 1 , J Schweitzer 3 , J Bailey 3 , T Whitham 4 , J Humphreys 1 , J Freeman 1 and R Vaillancourt 1 1 School of Plant Science and CRC for Forestry, University of Tasmania, Australia 2 School of Zoology and CRC for Forestry, University of Tasmania, Australia 3 Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, USA 4 Department of Biological Sciences & the Merriam-Powell Center for Environmental Research, Northern Arizona University, USA

The extended phenotype “The effects of genes at levels higher than the population” (Dawkins 1982; Whitham et al. 2003) Foundation species Dominant or keystone species that have a disproportionate influence on the ecosystem in which they occur from Whitham et al. 2006

Trees as foundation species Populus in USA • Conservation and management of biodiversity • Restoration ecology • Predict the broader impacts of anthropogenic changes (e.g. GMOs) • Community structure & evolution Whitham et al 2003, 2006

The case of Eucalyptus globulus • Dominant of lowland forest in SE Australia and Tasmania • A major plantation species in temperate regions of world • Extensive genetic resources available • Extensive quantitative and molecular studies of gene pool

Significant spatially structured genetic variation in numerous traits Localities from the1987/88 CSIRO range-wide collection of 600+ OP seedlots and racial classification Partition of variation within Gunns Ltd trials (46 traits, 13 races, 46 localities, 450+ families) genetic + environmental genetic 21% residual 5 trials race locality 74% between between within 9% plots plots 3% family two-tree 9% 8% 8% plots 68% block 5% Potts et al. 2004 Dutkowski & Potts 1999

Dependent herbivores respond to genetic variation in tree traits Autumn gum moth Brush tail possum Sawfly ( Perga affinis ) (Mnesampela privata) Oviposition is affected by Foliage intake is affected by Foliage damage greater genetic variation in genetic variation in formylated on thick barked trees the aliphatic ester (C 24 ) phloroglucinol compounds (r g = 0.44 ***) benzyl n-tetracosanoate (FPCs) [sideroxylonal A and macrocarpal G ] Dutkowski & Potts 1999 Jones et al. 2002 Jordan et al. 2002 O’Reilly-Wapstra et al . 2002, 2004, 2005a,b Rapley et al. 2004a,b,c Kelly 1997

Significant racial differences in defensive chemistry Adult foliage condensed tannins O’Reilly-Wapstra et al. submitted

How far does the effect of genetic variation at the race level flow through the ecosystem?

The experiment Gunns Ltd E. globulus base population field trial at West Ridgley, NW Tasmania (CSIRO 1988/89 OP seedlots) 1. 160 felled trees • age 15 years • 8 races across 2 replicates • 20 trees per race (10 families per race, 2 trees/ family) 2. 100 standing trees • age 16 years • 5 races across 2 replicates • 20 trees per race (10 families per race, 2 trees/ family)

Defining the extended phenotype Genetic Tree canopy communities (fungi, variation CHO CHO invertebrates, HO HO OH OH marsupials, [birds],) OHC OHC OH OH O O Canopy & leaf Log & disc decay decay rates & rates & communities communities Seedling recruitment (invertebrates, fungi) Bark communities (invertebrates) Chemical and Soil nutrients & nutrient leaching into micro-biota soil

Race of decaying canopy can affect soil quality Linseed bioassay of soil extracts taken from beneath decaying canopies after 7 months 60 % germination radical length 15 Radicle length (mm) length (mm) 50 % germination 10 % 40 5 30 0 20 Strz EO WO KI WT FI SET ST Strz EO WO KI WT FI SET ST

Race of decaying canopy affects litter invertebrate community Species richness Abundance Non-collembolan Pitfall traps beneath decaying Total invertebrates invertebrates canopies of trees from Southern 50 160 n individuals n species Tasmania and Strzelecki Ranges 35 110 60 20 S Tas Strzelecki S Tas Strzelecki Community NMDS ordination ▲ Strzelecki Ranges ○ Southern Tasmania Significant (P<0.05) variation in community traits was found

Tree race affects soil nutrient availability NO 3 levels in soil at base of standing trees 2.5 – 3 (ug/g OD resin/d) a a 2.0 ab ab 1.5 ab ab ab 1.0 b b NO 0.5 0.0 NE S W Flinders Is. Jeeralong NE Tas Southern Tas Westerrn Tas Flinders Strzelecki Tas Tas Tas Island Provenance Resin bags at Race base of tree

Tree race affects bark community Height of loose bark All loose bark & … Bark retention 6 c associated invertebrates Height (m) c c bc 4 removed from the trunk ab c a a of 100 trees 2 0 Flinders Northeast Southern Western Island Tasmania Tasmania Tasmania Arthropod abundance Species abundance 60 b n individuals b b 40 b a 20 0 30-50% of individuals are STRZ FI NE S W spiders and other TAS TAS TAS predators Race

Conclusion There is increasing evidence for extended community and ecosystem effects of genetic variation at the racial level in E. globulus , but their stability and extent are as yet unclear . Community and ecosystem genetics is an emerging field in ecology. Forest trees are key study organisms and studies will increasingly focus on lower levels of genetic variation with community heritability H 2c / h 2c estimates and QTL c studies appearing.

Thank you We thank the Gunns Ltd and Forestry Tasmania for inkind support and access to field trials Funding is provided by Australian ARC Discovery and USA National Science Foundation FIBR grants Photo: S Foster

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