Cane toad cane toad

Selection pressures upon organisms

Ecological Niche - Kakadu National Park

Biotic factors

Poison (bufotoxins)

if exposed to, results in death/or sickness

adaptations that arise as a result

Structural Adaptations

Physiological Adaptations

Behavioural adaptations

Red-bellied blacksnakes possess genes that confer resistance to the toad's poison (through chemoreception)

Structural adaptions are sparse. As many adaptations occur within the behavioural, and physiological spectrum

Quoll parents have taught offspring to abstain from Cane toads

Native competition

able to forage within numerous habitats (not fixed to one)

other species bound to be endangered (due to toxins, and rapid expansion)

species will relocate or adapt to such colonisation

Native anurans will avoid digestion, or attempt to relocate by seeking new shelter

Species become aware of the physical structure (colour, length, etc) of Cane toads, thus, avoiding digestion

Species feed upon the ventral, to avoid triggering the release of poison (Bufotoxins)

Cane toad invasion does not elicit an effect upon most Australian Birds. More precisely, birds may experienced benefit as they can scavenge deceased Cane toads. Furthermore, the release of poison has no effect, due to the close evolutionary relationship Australian birds share with Asian birds, where toads with similar poison are incredibly common

Keelback snakes are capable of eating Cane toads without ill effect for unknown reasons

Abiotic factors

Indirect affects

As species change habitats seasonally, Cane toads are frequently expanding, thus, colonising most ecosystems which impede/or prevent other organisms from further breeding #

Depriving animals of essential sources (contaminating water, inundating shelters)

Selection pressures upon the Cane toad

Abiotic factors

Biotic factors

Cane toad's skeletal structure is un-conducive to frequent transportation

alternating seasons

hyper-expansion will result in spinal arthritis

if a collective of Cane toads change habitats on a frequent basis, this will result in minimal expansion, which is ultimately a benefit toward other species

offspring production may contain arthritis at early stages

vulnerability to predators capable of consumption; due to reduced movement

vulnerable to predators; primarily through psychological, and behavioural adaptation

Fishes avoid early Cane toad life stages as they can detect their noxiousness, as well as being able to consume Cane toads

dragonflies, freshwater prawn crabs and crayfish have been observed consuming Cane toad eggs without any effect. Perhaps, due to prior evolutionary change, or basic behavioural adaptation

Red-bellied black snakes persist within ecosystems where Cane toads are present. Thus, passing down characteristics to offspring. As they grow more tolerant, the probability of consuming Cane toads without death rises

Numerous species are forming adjustments in not only avoidance but consuming Cane toads through different means #

Eel-tailed catfish, glassfish, rainbowfish, et cetera, can consume Cane toads without any ill effect #

Cane toads require water (absorption) to endure survival

If their current habitat becomes dry due to season change, Cane toads must relocate for water absorption to prevent death

Cane toad activity

Despite the ability to engage within vast habitats, if not present within Wetlands, activity is bound to be reduced, as dry habitats impede the Cane toad (less water absorption, sunlight exposure which forces the Cane toad under shetter to avoid dryness, etc) #

impact upon organisms

Ground-dwelling arthropods are at incredibly high risk, due to the Cane toad's high density, and ability to consume hundreds of prey items in a night's stand

Cane toad tadpoles found preying on eggs of native frogs

breeding/habitat locations

Cane toads regularly disperse into woodlands and open forests from wetland habitats (vegetation provides shelter, if dry)

Cane toads breed in both temporary and permanent water bodies

Floodplains and sheltered habitats are ideal during the early-to mid dry season #

Cane toads inundate many of the major wetland habitats during wet season

Adapting species

beneficial impacts

Many endemic aquatic invertebrates are subject to Cane toad competition

Reduction in numbers of predators such as Goannas and snakes. Thus, this helps alleviate the impact upon ground-dwelling and nesting birds' species # #

Cane toads have heavily impacted feral pigs and cats. Which reduces damage to native fauna/flora and ultimately, the landscape of Kakadu National Park # #

Population level affects

,

Reduced Goannas

Feral cats declining

Feral pigs declining

Beetles declining

Snakes declining

Must maintain an optimum water level (reduction/rise in moisture may result in death)

Wolf spiders

Centipedes

Few snakes species due to chemical stimuli #

Cane toads decrease the population of Goanna's within Kakadu, this could reduce the level of predation on crocodile eggs #

Residents have reported a decline in the green tree frog

Barramundi fish, and sooty grunters display signs of distress when trying to feast upon Cane toads; thus, such an instant reaction will assist the fish in avoiding Cane toads

Native competition

Frog tadpoles (ornate burrowing frog)

Fish species able to detect cane toads #

Northern quoll, and northern bandicoot declining rapidly

Frog tadpoles unable to detect the toxicity of Cane toads

Observed to prey upon the same species

Snails (larvae, backswimmers, leeches)

affected by poison

defensive mechanism (Bufotoxins)

Ecosystem - Kakadu National Park

Wetlands

Fauna

Reptiles

Invertebrates

Native

Ornate burrowing frog

Goannas (Varanids)

Saltwater Crocodiles

Elapid Snakes

Large-Wolf spiders

Termites

Ants

Flora

Dense vegetation

Leeches