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
und
inci
dent
ligh
t (ìmolm-2s-1)
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invaded non-invadedHabitat
Mea
n ca
nopy
co
ver
(%)
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13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8
January FebruaryDate
Tem
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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250
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
No
. ri
pe
fru
it p
er p
lan
t
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Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Month
No
. n
ativ
e sp
ecie
s in
fru
it
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
0
0.2
0.4
0.6
0.8
1
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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20-25
25-30
30-35
35+
Diameter (mm)
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Tota
l num
ber o
f ind
ivid
auls
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Diameter (mm)
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80
To
tal n
um
be
r o
f in
div
idu
als
0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100
100-150
150-200
200+
Circumference (cm)
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75
100
125
To
tal n
um
be
r of
ind
ivid
uals
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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2
4
6
8
Mean
nat
ive
shoot dry
weig
ht (g
)
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