Impacts of Invasion of Bitou Bush on Coastal

Communities

Kris FrenchInstitute for Conservation Biology & Law

University of Wollongong, Australia

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Bitou bush � Chrysanthemoidesmonilifera spp. rotundata

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invaded non-invaded

Habitat

Gro

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inci

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ligh

t (ìmolm-2s-1)

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invaded non-invadedHabitat

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January FebruaryDate

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pera

ture

(˚C

)

DarkerCoolerMoister

Ecosystem changes

Lindsay and French (2005) J Appl.Ecol, 42,556�566

Ecosystem changes

Bitou leaves decompose fasterMore litter and more nutrients tied up in litter in

native areas

Lindsay and French (2004) Forest Ecology and Management 198, 387�99

Native leaves

Bitou leaves

Months

Per

cent

mas

s re

mai

ning

Litter Invertebrate changes

French and Eardley (1997) andLindsay & French (2006) Biological Invasions 8: 177�192

M Bulbert © Australian Museum.

Increased in bitou bush habitat

Decreased in bitou bush habitat

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Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

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. ri

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fru

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er p

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Gosper 2004Aust J Bot 52,223

Bird communities

www.bencruachan.org

Canopy foragers

steffen-oppel.com

www.oiseaux.net

Understorey species

www.townsville.qld.gov.au

Plant feedersLarge carnivores

DIDN�T CHANGE

DECREASED INBITOU HABITATS

French & Zubovic(1997) Wild. Res. 24, 727-735

Bird behaviour

lucaantara.blogspot.com

New Holland H�eater Little wattlebird

Silvereye

Superb Fairywren

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1.2

LWB NHHE SE SFW

Species

% o

bse

rvat

ion

s

Ben OwersHons project

Fore dune and hind dune vegetation

� Reduced climber richness

� Reduced graminoid richness

� Reduced herb richness

� Lower cover at ground levels

� Reduced shrubs� More open

canopiesMason & French (2007).

Biol. Cons. 136, 246-259.

Fore dune and hind dune vegetation

Disadvantaged by bitou invasion� Actites megalocarpa� Correa alba� Desmodium varians� Dianella crinoides� Dichondra repens� Microlaena stipoides� Pelargonium australe� Pittosporum revolutum� Pteridium esculentum� Rapanea variabillis� Scaevola calendulacea� Senecio lautus� Spinifex sericeus� Zoysia macrantha

� Disadvantaged by bitou invasion and management

� Acacia longifolia var. sophorae� Acacia ulicifolia� Banksia serrata� Carpobrotus glaucescens� Cynodon dactylon� Gonocarpus teucroides� Hibbertia linearis� Hibbertia obtusifolia� Leucopogon parviflorus� Oxalis rubens� Poa poiformis� Pratia purpurascens� Rhagodia candolleana� Ricinocarpos pinifolius� Solanum prinophyllum� Viola hederacea

Meta-analysis

Mason, French and LonsdaleIn prep

Mechanism of Invasion

How is it causing these changes in vegetation?

Replacing adult plants through mortality?

Or Affecting the germination and

establishment of seedlings?

Mechanisms: Effects on adult plants

There are no impacts on growth, reproduction or physiological function of adult plants.

0.5510.8980.6660.963L. longifolia

0.3600.6830.4430.231M. elliptica

0.5760.8800.3900.983C.alba

p value

p valuep

valuep

valueSpecies

Fv/FmReproductive:

vegetative budsVegetative

budsFlower

abundance

Effects on population structure

Reproductive maturity Reproductive maturity

Reproductive maturity

Losses in small individuals or lack of recruitmentChanges in population structure

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Diameter (mm)

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Diameter (mm)

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Circumference (cm)

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Correa alba, Monotoca elliptica, Lomandra longifolia

Native species affected more strongly by growing with bitou than growing with conspecific

BA BA+BA BA+BI IS IS+IS BI+IS

condition

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Mean

nat

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shoot dry

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ht (g

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Banksia

Isolepis

Allelopathy

Bitou

Acacia

Bare soil

Summary

� Significant changes to ecosystem processes and habitat characteristics

� Impacts on faunal communities

� Decreases in plant species richness� No competitive effects on adult native

species

� Effects on seedlings from both resource and interference competition

Acknowledgements� Anita Zubovic� Sarah Buckley� Ben Owers� Kristen Prattis� Naomi Strakosch� Karen Eardley� Carl Gosper� Liz Lindsay� Tanya Mason� Emilie Ens

�Sharon Robinson�John Bremner�Mark Lonsdale�Natalie Sullivan

Funding�Hermon Slade Foundation�National Heritage Trust�CSIRO�CRC Weeds�DPI�DECC�Land and Water Australia

Thank you