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CANE TOADS IN KAKADU NATIONAL PARK (Introduction (Introduced in 1935 (102…
CANE TOADS IN KAKADU NATIONAL PARK
Introduction
Introduced in 1935
From Hawaii
102 released
200+ million today
Native to Central America
Cane Beetle population control
No effect
Ecological Niche
Original Niche
Cane Beetle population control
Current Niche
Invasive species
Unbalanced ecosystem
competition for resources
Competing species readapt
Red Bellied Snake
Smaller Heads
Large Coads > Toxin Amount
Large headed snakes die
Selected against
Northern Quoll
Training Quolls
Feeding Toad Sausages
"Toad Aversion"
Native populations decline
Kakadu National Park
Biome
Wetlands/Floodplains
Wet conditions
Optimal for amphibians
Live and Breed
mover further when wet
Woodlands and Lowlands
Easy to traverse
Can forage in wet areas
Use burrows
Biotic Factors
Opportunistic feeders
Abundance of food
Few natural predators
No decline in population
Fast Life History
Reproduce Quickly
8,000-35,000 eggs
Up to 8 days to hatch
PICTURE 2
(Photo Source: The University of Western Australia)
Two times a year
Native Species
Negative Impact
Competition
Native frogs
Habitat
Food
Predation
Poison glands
Death of predators
Quolls
Red Bellied Snakes
Various birds
Goannas
Spread Disease
Abiotic Factors
Temperature
19-34 degrees celcius
Cane toads
Optimal temp 5-37°C
River/Lake Sytems
Cane Toads
Need water to breed
Rich Soils
Burrows as refuge
Size of Park
Cane Toads
move 200m every night
change location frequently
Terrain
Easy to traverse
Chemicals from humans
susceptible if skin contact
Selection Pressures
#
"Natural Selection"
Phenotypes
Develop Stronger Legs
Faster Invasion
Improved Hopping Style
.
Faster Toads breed
Invasion Front speeds up
10km/y - 60km/y
PICTURE 1
(Map Source: Urban et. al. University of Sydney)
Cane Toad
Effect on other species
Toxic Glands
Predators
Die from non-immunity
Population number loss
Selected against
Develop traits/adaptations
Red bellied snake
Smaller heads
Cannot eat larger toads
1 more item...
Northern Quoll
Training sausages
Dislike to Toads
Black Kite (Bird)
Attack the belly
No toxins
Selected for
Abiotic factors
#
Management Strategies
High Stress on bodies
Vulnerable Immune systems
Release lungworm/parasite disease
Lungworms
Slow down adults
Invasion Front
Kill 30% baby toads
Relocating Native Species
Away from Cane Toads
Preserve the Species
Prevent extinction