Terrestrial Fauna L13-23

Describe Narrm / Melbourne’s distinct bioregions

Bioregion	Where it is on the map	Main landscape	Typical vegetation
Victorian Volcanic Plains	West and south-west	Flat basalt plains	Grasslands and grassy woodlands
Gippsland Plain	East and south-east	Coastal plains and wetlands	Heathlands, wetlands and forests
Central Victorian Uplands	North and north-east	Hills and mountains	Eucalypt forests and woodlands

Kulin seasons are marked by…

Bio-indicators (particular species at specific stage of life cycle)

• Flowers, animals, changes in environment

  • Phenology: track life cycles

• Not dictated by Gregorian calendar

• Melbourne has 7 seasons

In what way has urbanisation changed the natural environment?

• Vegetation and water courses altered

• Creates an extreme environment

  • Altered access to resources (food / shelter)

  • Novel structures and surfaces (e.g. birds with glass, worms with concrete)

  • Introduced species

  • Noise

  • Light

  • New sources of mortality — cars, dogs, cats

  • Pollution (plastics, metals, bioaccumulating toxins, etc.)

Urbanisation

• 8.31 bill humans

• 6.7 bill people will be in urban centres by 2050

• Commercial and residential development is the 3rd most frequently cited threat to species on the IUCN Red List

• As natural habitats are degraded, the urban environment becomes more important as a potential habitat for animals

• What is good for biodiversity is good for humans too, Green spaces:

  • Linked to lower stress levels (cortisol)

  • Linked to reduced risk of heart disease, diabetes and obesity

  • Tree cover reduces urban heat island effect

  • Trees improve air quality

• But the structure of green spaces matters for biodiversity

  • Mid-storey: The best green spaces have complex structures and a diversity of species

Introduced urban wildlife

• Many non-native (introduced) species in urban areas

• Arrive with humans

• Often already adapted to human environments (in other parts of the world)

• Intentional or accidental

  • Intentional (E.g. The Acclimatisation Society of Victoria 1861: Sambar deer, pigeons, Indian mynas, foxes)

  • Accidental (E.g. Snails, Argentine ants, daddy longlegs)

Native urban wildlife

• Simplified environment favours generalists

  • Resource increases for ecological generalist species

    • E.g. Common brushtail possum - Trichosurus vulpecula

      • Density is higher in urban than non-urban areas

      • Omnivore

      • Adaptable to human structures and non-native vegetation — Higher abundance of den sites (bins, roofs if not tree hollows) = more possums

      • Territorial

• Being pre-adapted to a resource valued by humans

  • E.g. Maned wood duck - Chenonetta jubata

    • Able to exploit an abundant food resource - grass (lawns are valued by humans)

      • Sports fields, golf courses, parks and gardens, verges

    • Nesting is flexible — cavities, artificial nesting boxes and other human structures are used

    • Can nest a long way from water (~5km away) — not restricted by environment

  • E.g. Honeyeaters

    • Usually territorial

    • Can take advantage of nectar from showy plants like proteaceae (humans like)

• A combination of adaptability and mobility

  • E.g. Grey-headed flying-fox — Pteropus poliocephalus

    • Urban heat island = higher minimum temps

      • More stable temp in the city e.g. no frost in the winter

    • Increase in food species

    • Loss of natural habitat outside cities

    • Black flying-fox species pushing south — aggressive and territorial

    • Humans cut down and remove their habitats outside = pressure, pull inwards (food and roosting resources lost outside city)

• Novel behaviours in some populations — synurbanisation

  • Specific population in urban areas develop novel traits to persist

  • E.g. Sulfur-crested cockatoos - Cacatua galerita

    • Using intelligence to exploit novel resource (human waste)

    • Social structure allows learning

      • Cultural practices spreads in a population

  • E.g. bin raiding by ravens, foxes, etc

  • E.g. Possums make bins roosting sites

Urban resources can create an Ecological Trap

Ecological Trap: the illusion of being in a suitable habitat but long-term not suitable (reduced survival or lower reproductive success)

• Animals use cues for suitable habitat to move into suburban areas

  • Food availability

  • Shelter

    • E.g. Owl hunts possums (found in urban areas) —> large food source BUT owls are large and need big tree hollows (almost none in melb - don’t support breeding)

• False cues

  • Reduces survival of animals weighing into that signal

  • E.g. insects navigating with light are mislead by light pollution

Urban environments can support threatened species. What are threats to their ongoing persistence in urban areas?

• Hollow loss from tree removal

• Weeds replacing food and shelter

• Toxins and pollutants (including light, sound, and human waste)

  • Possums have PFAs (endocrine disruptor: toxins are accumulating) in their livers

  • Birds have plastic in their stomachs

• Predators and competitors

  • Many introduced species

  • Out of balance system with aggressive native species also dominating

  • E.g. Cats — no.1 predator in urban environment, along with foxes

Which urban animal most likely deposited the scat shown?

Common brushtail possum

Australia is the 2nd driest continent on Earth. What are 2 predominant features that impact animals?

1. Climate

2. Physical geography

How does climate impact animals in arid zone?

1. Rainfall

• Rainfall is unpredictable and thus availability of food for animals is also unpredictable

• Arid: defined as insufficient rain for agriculture

  • Arid areas <250 mm

  • Semi-arid areas <500 mm

• Seasonality: wet and dry seasons, but timing differs in N and S

• Australia’s deserts are not the driest in the world

• Rainfall variation in arid Aus: 10% higher compared to other arid zones around the world

  • E.g. Alice Springs: mean annual rainfall: 281 mm, range: 60-903 mm !!!! (impacts food)

• Patchy distribution: within districts and between years

• After rain: rapid plant growth, flowers and seeds provide food for animals

2. Temperature extremes

• Up to 45°C + during day

• Impacts water requirements and metabolism of animals

• Can reach freezing point at night

How does physical geography impact animals in arid zone?

1. Environment

• Vast flat low areas (stony or land), vast sand dunes and some low stony hills

• Limited areas of mountainous ranges, and those ranges are low (all <1500 m) E.g. Pilbara

• Landscape is highly weathered = low N and P

2. Refuge

• Hills and caves provide refuge for animals E.g. Yellow-footed Rock Wallaby

• When rain dries out, cracking soils also provide refuge for animals E.g. Planigale

• Vast, very flat areas in arid zone may have large areas of grasses E.g. Triodia sp. “Hummock grasses”

  • Microhabitat for small animal species

  • Provides shelter and seeds (food)

  • Managed by fire

• Hard to find refuge in stony desert or ‘gibber plain’

  • Polished, pebbly surface (wind tends to erode and polish these massive plains to look like gravel)

  • Animals that can move back and forth long distances can get around these inhospitable areas

In Australia’s arid regions, physical geography and climate leads to low productivity and therefore:

• Low food / water availability for animals

• Unpredictable environments / highly variable food and water availability for animals

• It is a highly weathered landscape which has resulted in low soil nutrition

• Rainfall pattern is low availability and high variability

What are challenges / constrainsts for animals in arid zones?

• Poor nutrient soils

• Overall low food availability and low quality

• Unpredictable water and food supplies

• High temperatures (Jan/Feb >40°C)

What are the 2 categories of ecological, physiological, and behavioural adaptations animals have?

Drought evasive: not active during really dry periods

• dormant stage as egg or adult

• develop and reproduce rapidly after heavy rains

• OR move away from drought areas

Drought tolerant: often long-lived species

• slower life cycle

• tolerate very low levels of moisture and food (physiology) — have low energy / water requirements

• behavioural strategies to assist survival

Compare vertebrates and invertebrates in arid zones

Vertebrates:

• Mammals and birds — endothermic = relatively high energy needs

• Reptiles and frogs — ectothermic = lower energy requirements than endo

Invertebrates:

• Highest faunal diversity, ants and termites are dominant groups

• Ectothermic and very small = lower total energy requirements than vertebrates

  • Don’t require permanent access to an energy source

  • Get most water from prey, don’t need a body of water to drink from

Ectothermic animals are sensitive to changes in air temp yet are common in arid zones due to their lower MR and therefore energy requirements.

What are drought-evasive strategies of animals?

1. Remain dormant as egg or adult during dry times

• As egg: E.g. Shield shrimp

  • Cysts hatch and develop into adults very rapidly - approx 2 weeks after rain

  • Incredibly fast life cycle

  • When puddles dry out, cysts in ‘suspended animation’ (diapause) for years

  • Cysts are very tiny, can be dispersed by wind

  • Hermaphroditic = can easily swap gametes

• As adult: E.g. Burrowing frogs (Cyclorana spp., Neobatrachus spp.)

  • Water conservation strategies:

    • Aestivation (lower their metabolism and remain inactive)

    • “cocoon” (to store water —> holds water under layer of skin)

  • Reproductive strategies:

    • Emerge and breed rapidly after rain

2. Migration to areas with water / food E.g. Birds — Budgerigars (arid zone distribution)

• Behaviour: migratory / nomadic — flocks travel up to 1500 km to find food and water

• Breed opportunistically when grass seeds (food) become available after rain

What are drought-tolerant strategies of animals?

1. Insulate against extremes such as high temp and low water availability

• E.g. Honey pot ants: Special replete workers act as storage pots to feed colony —> in deeper part of the nest (has constant temp)

• Arid zone mammals also

  • Regulate temps (e.g. via coat colour, evaporative cooling, behaviour, etc.)

  • Avoid high temps (behaviour: nocturnal, use of burrows)

  • Water conservation (physiology)

2. Energy conservation E.g. Southern Hairy-nosed wombats (Lasiorhinus latifrons)

• Avoid high temperatures

  • Spend very little time above ground (use burrows)

  • Nocturnal (avoid highest temps)

• Breeds seasonally

• Relatively inactive (radio-tracking studies)

• Survive on low quality food

  • Eats high silica, low N and P

  • Gut is able to get the most nutrients possible

• Relatively low metabolic rate (for a mammal)

  • Reduces food and water requirements relative to mesic zone “cousin” - the common wombat

3. Maximise access to water E.g. Thorny devil (Moloch horridus)

• Specialised skin texture (morphology) to capture dew and rainwater

• Scales are surrounded bby tiny interconnected channels that attract water

• Water is then funnelled from these into the mouth

4. Access water from food E.g. White-winged fairy wren — a tiny arid zone specialist

• Food selection: diet of insects = high water content

5. Physiology to conserve water E.g. Eyrean grasswren (Amytornis goyderi)

• Very efficient kidneys — assists water retention

• Extract water from dry seeds and supplement with small insects

• Long thought to be extinct: secretive behaviour, remote distribution

6. Energy conservation in mammals E.g. Fat-tailed dunnart (Sminthopsis crassicaudata)

• Diet: insects = 70% water

• Low MR

• Fat storage in tail enables them to go into torpor (slows down metabolism and saves energy)

• If insects are not available, they survive off fat

7. Water conservation in mammals E.g. Spinifex hopping mouse (Notomys alexis)

• Diet: seeds (not as scarce or variable as insects but low in water)

• Minimise respiratory water loss

• Very dry faeces (water reabsorbed in hindgut)

• Super-concentrated urine

• If dehydrated, they can change how they source energy for processes in the body to produce metabolic water

Describe Australia’s alpine zone

• 0.15% of Australian landmass – very small total area

• Mean temp. of warmest month <10°C (trees don’t thrive)

• Snow 2-3 months per year – strongly seasonal conditions

• 25% of Australia's rainfall (a lot of rainfall)

• Significant area for: water supply, recreation, nature conservation (contains unique group of native species)

• Australian alpine zones are distributed in a series of disconnected regions from Tasmania to Southern NSW

• Habitat for alpine animal populations is naturally fragmented due to variation in altitude. Populations are:

  • isolated in tiny land area

  • genetically distinct

  • more vulnerable

Is the alpine environment predictable & strongly seasonal, or unpredictable and variable?

Predictable & strongly seasonal.

• Extreme temperature differences

• Prolonged cold - winter, night and cloud

• Permanent water & abundant moisture – high rainfall,
  condensation, snow melt

• Flora: mostly herbs and lichens (i.e. small — very low biological productivity)

• Snow gums (sub-alpine woodlands)

• Also some energy input from sub-alpine areas through flying insects, wind-blown detritus, pollen and seeds

  • Nutrient delivery from winds coming upslope

  • Brings detritus and growth from down the mountain up the mountain

Alpine zone plants

Flora: small plants, summer flowering

• E.g. Alpine grasses, Peat bogs, Alpine daisies

• Low growing

Snow gums (sub-alpine)

• Leaves can withstand freezing (waxy)

  • Doesn’t allow ice crystals to form —> no damage to the structures, no damage to tissues

• Do not occur on mountaintops (not in alpine zone)

• Highly susceptible to fire

  • Grow slowly and do not recover (unlike eucalypts)

Impacts of climate change on the alpine zone

• Distribution of specialised alpine plants and animals is very restricted to the zone between tree-line and summit

• As the continent warms, alpine adapted animals will have to move higher to access preferred conditions

• Alpine is moving up the mountain —> bands of habitat moving up eventually is lost —> entire mountain is converted to sub-alpine rather than alpine conditions

• Australia’s mountains are relatively low: climate change may leave specialised alpine species with nowhere to go

• Concerns: whether it snows and how deep snow gets

  • Determines how long snow will last

  • Snow is insulative blanket for lots of animals over winter

What changes have occurred and are predicted to occur in the alpine zone due to climate change?

• Tree-line at Mt Hotham in Victoria has already moved up 40m to an area that had not had trees for past 25 years

• Expected 18-66% reduction in snow cover by 2030 and 39-96% by 2070, 100% loss by 2100

• With small change in temp, the tops of 6 mountains will be the only remaining alpine ecosystems

What are conservation issues for alpine areas?

• Extensive recreational use

• Human infrastructure: loss of habitat, erosion, fragmentation, pollution etc.

  • Clears vegetation and rocks

• Increasing frequency of fire

  • Due to drought

• Cattle and sheep (grazing and trampling)

  • Alpine does not cope well, does not recover even after ~60 years

• Feral animals – rabbits, cats, brumbies

Australian alpine zone fauna

• Higher the altitude = Lower the species diversity

  • Less diverse than arid zone

    • Arid has larger land space

    • Faster life cycles in arid = more species evolving overtime

• No truly alpine birds - migrate seasonally e.g. flame robin (in for summer, out during winter)

• Low diversity of reptiles (only 1 species found over 2000m in altitude – Alpine skink)

• Very few mammals, largest herbivores absent

• Invertebrates most diverse and abundant group!

• All species experience highly seasonal food availability

Compare endotherms and ectotherms

• Endotherm: MR drives body temperature

  • High body temp and fast reaction rates

  • Active across a wide range of environments

  • High energy requirements all the time to maintain MR

• Ectotherm: Body temperature drives MR

  • Body temp fluctuates with environmental conditions

  • Variable reaction rates (reliant on external thermal energy)

  • Active when conditions are suitable

  • Less energy used when conditions are not suitable

Ectotherms in the alpine zone

• Lower energy requirements – useful in an energy poor environment

• Body temp declines with environmental temperatures

  • Reduced metabolism and activity

• Strategies (adaptations) to avoid freezing

  • dormant life stage

  • behaviour e.g. seek refugia (hide from cold e.g. snow blanket)

  • migrate

Invertebrates in alpine zone: adaptations to low biological productivity and cold

E.g. Tasmanian scorpionfly (Apteropanorpa tasmanica)

• In winter consume moss – larvae only active in winter

• Gather around edges of snow drifts and feed on detritus as it is released during snow melt (this is blown up from sub-alpine areas)

• Enzymes and body physiology is adapted so the optimum temperature is really low

E.g. Mountain grasshopper (Monistria concinna)

• Small size (SA:Vol is small)

  • occupy sheltered micro-climates

  • chunky to retain body heat

• Stenothermic: physiology adapted for a narrow range of low temps

  • produce anti-freeze (series of proteins that prevent ice crystals forming inside their cells)

    • microbiome in their gut causes nucleation points for ice to form at higher temp = crystals grow slowly and don’t do damage to tissues

• Small, reduced wings

  • Cannot fly, or hop far

  • Escape predation by camouflaging

Invertebrates in alpine zone: Behavioural thermoregulation

E.g. Chameleon grasshopper (Kosciuscola tristis)

• Remain active all day (generally adapted to cooler conditions, but can cope with large temperature variation)

• Movement in & out of sun

• Thermal melanism:

  • Colouration is not for camoflage but to control body temp by changing how much thermal energy it is absorbing or reflecting at any one time

  • Cold conditions (higher altitude): darker/black, thus absorb heat

  • Can change throughout day (dark —> light —> dark)

Ectotherm vertebrates in alpine zone — frogs

• Over-winter in alpine areas (low mobility, don’t migrate)

• Winter: become totally inactive

• Bury in microhabitats e.g. peat bogs, snow blanket

E.g. Corroboree frogs: Evolved life history adaptations to cold

• 2 species – northern and southern (isolated from one another due to speciation overtime)

• Occur mainly >1800m elevation

• Males dig burrow in sphagnum moss bogs & call

• Females lay in this nest, but development is delayed until late winter (melt starting), and is slow metamorphosis as the burrow fills with water

  • Due to shorter periods of water availability / not enough rainfall / snowfall —> ponds dry up faster —> not enough time for its evolved slow metamorphosis process to transition to an adult before everything dries

• Snowmelt: when burrows fill with water in spring they hatch and mature

• They are rare and declining

2 alpine endotherm strategies

• Migratory

  • many sp. avoid cold by migrating

  • E.g. birds, larger mammals like wallabies

• Permanent residents

  • some sp. stay active (no state of dormancy)

  • some use torpor (adjust body temp) e.g. small mammals like Mountain pygmy possums

Alpine endotherms active during winter - give an example

E.g. Common wombat

• Active all the time during winter

• Medium body size

• Mammals, thus high MR so can keep warm/active

• Paws can dig out grasses and plants from snow (access to food)

• Small SA:Vol = Efficient at retaining heat generating through metabolism of food

Daily adaptive hypothermia: Torpor

E.g. Mountain pygmy possum, Chocolate wattle bat

• Decreased body temperature

• Torpor = Reduced MR, respiratory rate, heart rate

• Curl up (minimise surface area and thermal energy exchange)

• Occurs in small endotherms – reduces their risk of starvation & conserves energy

• Often a response to low food availability

Typical pattern of torpor in small mammals

• Rapid entry into torpor - MR drops, body temp drops by passive cooling

• Animals exit torpor by turning MR up, body temperature follows

• Can be short-term (daily) or long-term

Seasonal adaptive hypothermia: Hibernation

Seasonally-induced deep torpor, longer bouts

Only two Australian mammals: Mountain pygmy-possum and Echidna

• Fatten-up prior to winter

• Retreat to hibernaculum (safe place when you can’t move) and go deep into torpor

• Test drops in body temp

• Periodic arousal to find water

Breeding patterns in alpine zone animals

Short period of warmer weather — growing season & breeding season are both short but predictable (unlike in arid zone)

• Some species exhibit dormancy at other times of year (i.e. during non-breeding season)

• Invertebrates: speed of development often not as crucial as in arid areas. Life-cycle usually completed in a season.

• Larger animals (e.g. Mountain pygmy-possum) synchronise their breeding season, and have fast growth before winter

CS: Climate change impact on breeding patterns of Mountain pygmy possum (Burramys parvus) & Bogong moths

Mountain pygmy possum (Burramys parvus)

• Highly seasonal

• Entirely limited to alpine regions

• Thought extinct until 1966, now endangered

• Habitat: alpine boulder fields and rock screes

• Mating occurs when snow melts and Bogong moths (food) arrive (store body fat)

• Road was built which divided sexes: they couldn’t cross to breed (would get run over)

  • “Tunnel of love” built at ski resort - sexes occupy different habitats that had been fragmented by a road

    • High quality upslope (above the road) habitat was where females were congregating (have to put energy into reproduction)

    • Lower quality downslope territory was held by males (don’t raise young)

Bogong moth (Agrotis infusa)

• Small grey-brown moth (wingspan approx 4cm), alpine seasonal migrant

• Larvae winter in pastures in Sth QLD, NSW & SE Vic, but food plants dry off over summer

• Intolerant of summer heat

• Adults migrate to alpine areas, shelter in caves & crevices >1500m during spring/summer up to 17,000 individuals/m2

• Aestivate when in alpine zone - survive on fat
  stores

• Climate change is a severe threat

  • Because of light pollution up and down East Cost, moths get lose and off course (they use the moon)

  • They don’t make it to the high country = smaller food source for possums

Effects of climate change on mountain pygmy possums

• Threaten survival because Burramys need 70cm-1m of snow to keep warm during winter (acts as a ‘doona’, keeping temp at approx. 2ºC)

• The possum’s entire climatic habitat will be lost with only 1ºC warming

• Also potential impacts on key diet item – Bogong moths

• Environment is highly fragmented

  • where there are small populations, their genetics can start to be degraded

  • All individuals become very similar, no diversity in population and that can affect fitness of individuals

• Possums were translocated from Mt Hotham to Mt Buller where possums were declining

  • hybrids are bigger and reproducing more successfully

Does North or South Australian rainforest have higher animal diversity?

North: Tropical rainforest

• Higher animal diversity

• Warmer, massive rainfall

South: Temperate rainforest

• Lower animal diversity

• Cooler

Tropical rainforests in Australia

• 70-100% canopy cover

• From sea level to 1600m

  • Upland RF (cooler) = fewer animal sp

    • Higher altitude — Fewer but more unique species, similar to alpine

  • Lowland RF (warmer) = more sp

• Rainfall is reliable, >1500m/yr

  • Massive amt of rain, large amt of water supports productivity

• Small area: Only 1-2% of the total land area of Aus is considered tropical

Australia tropical rainforest diversity

• Exact number of invertebrate species unknown, but it is very large

  • >75,000 sp. endemic

• 128 bird sp. (16.5% of Aus birds)

  • Behavioural and species diversity of birds is strong in tropical environments

  • E.g. Birds of paradise i.e. Victoria’s Riflebird

  • E.g. Palm cockatoo

• 160 reptile sp. (23% of Australia’s reptile fauna)

  • E.g. Lace monitor (goanna)

    • Big distribution overlaps with tropical rainforest (rainforest is part of their range)

• 47 frog sp. (23% of Australia’s frog fauna)

  • E.g. Stony creek frog Litoria wilcoxii

    • Amplexus: Male embraces female and triggers her to release eggs for him to externally fertilise

    • Sometimes males mistake cane toad for females (can die as cane toads may release poison from glands if stressed)

• 89 mammal sp. (1/3 of Australia’s mammal fauna)

  • E.g. Striped possum

  • E.g. Musky rat kangaroo (not found anywhere else)

Why do tropical rainforests support high animal diversity?

Habitat patchiness + high complexity + high productivity = massive biodiversity

Habitat patchiness at a local scale

• Tropical rainforest in North Queensland: large areas of habitat

• But varies at a local scale: potential barriers to movement which restrict / prevent populations of some species from mixing

• Habitat patchiness (local-scale) can result in the isolation of sub-populations of some species (potential for speciation)

  • over time there might be changes in genetic structure of 2 populations because there is no gene flow — through changes in the selection pressures in the 2 populations OR just random chance (genetic drift)

Habitat patchiness at a larger scale across landscapes

• Geographical barriers (e.g. valleys b/w mountains) can also result in the isolation of sub-populations

• PNG has significant mountain areas but also in Aus

TK illustrate the links between Australia and PNG’s rainforest fauna

CS: In PNG Matschie's TK & Dingiso (TK)

• Some tree kangaroo populations are isolated on mountain tops

• Found in the tropical rainforest as animals that returned from the ground back into the trees

• Evolved ~5mya

• The musky rat-kangaroo is the closest living relative to the ancestral phalangerid (possum) from which kangaroos evolved (including tree kangaroos)

  • Some tree kangaroos have re-evolved some traits that we see in things like possums i.e. rotating ankles, muscular forearms, short legs (different from kangaroo)

CS: In Aus Lumholtz TK & Bennett’s TK

• 2 species, distributions don’t overlap (Daintree river has become a geographic barrier)

• TK were once widespread, but distribution has contracted with rainforest contraction as the continent dried out — extant sp now restricted to tropical rainforests

• The fossil records of TKs show that speciation and the diversity of this group actually happened across the continent (not just in Tropical rainforest)

Habitat patchiness: Explain how tropical rainforests are biodiversity hotspots

• Climate becomes cooler/wetter —> Rainforest expands  —> Animals move into newly available rainforest —> Populations become separated in different areas —> Over time → speciation (new species)

• Climate becomes warmer/drier —> Rainforest contracts —> Suitable habitat disappears from much of Australia —> Species' ranges shrink —> Species become concentrated in remaining rainforest

• When rainforest expanded, animals could spread into new areas and populations could diversify. When rainforest contracted, those species were pushed back into the remaining rainforest

• The rainforest becomes a refuge for all the species that may have evolved over a broader scale in Australia and now are only found in this really small patch of country in the tropical north

Habitat patchiness: Habitat / geographic barriers impact variably on animal species depending on their…

• Mobility

  • E.g. Bat vs Antechinus

    • Bat: able to fly = adapted to urban environments — more resilient to the degradation and fragmentation of habitat if they can move across non-suitable habitats

    • Antechinus: Much harder for them to cross vast distances if there is fragmentation happening = more likely to see speciation

• Body size

  • E.g. Antechinus, insects

    • Small body size = less likely able to cross over geographic barriers

• Degree of habitat specialisation

  • E.g. Dingo

    • Very broad diet = capable of surviving in lots of different environments = less likely to see speciation based on geographic change because they're able to move through multiple different types of environments and still survive and reproduce

Habitat patchiness: Diversity of rainforests increased through faunal links with PNG and Asia continent (Australasian rainforest fauna)

• The mobility of species and their ability to cross “habitat barriers” has an important influence on their distribution and diversity

• Faunal diversity is a result of current movements and past land bridge

• Approx. 50% of Australian tropical rainforest birds are shared with PNG

  • Some migrate back and forth, some distributions span both land masses

E.g. Buff Breasted Kingfisher

• Stays over-winter in PNG & migrate to Aus to breed in lowland rainforests in the summer

• Form pairs, establish territories, nest in termite mounds (protected, insulated, dry)

• Adults migrate back to PNG March-April (juveniles later)

  • Juveniles are left behind with genetic imprinting, they are instinctively triggered to move back to PNG as weather starts to cool down

E.g. Little Red Flying Fox (mammals)

• Fission fusion structure

  • Move between camps all the time

  • There is a mix of animals roosting in different parts of the range over the year — it's one massive population through PNG and the top end of Australia

• Flying foxes highly mobile, capable of long-distance movements

• Effectively one large population in Aus and PNG

E.g. Amethystine python

• Australia’s largest snake up to 8m, major predator in rainforest

• No migration, thus PNG and Australian populations now isolated

• Torres Strait = current geographic barrier

• Starting to see evidence of speciation

How does habitat complexity of rainforests support high animal diversity?

• Diverse possibilities of habitat niches = more diversity at each layer = animals find a specialisation and support a specialised diet

• Carnivorous birds exploit high complexity

  • E.g. Red Bellied Pitta specialises on rainforest snails

    • Good at finding snails in the complexity of the rainforest

    • Diversity of snails and food is able to support an animal that only eats snails

    • Level of competition in these environments are quite low

How does high productivity of rainforests support high animal diversity?

• Frugivore (herbivorous) birds exploit high productivity and lots of fleshy fruit available in rainforest

  • E.g. Superb Fruit Dove and Fig Parrot

    • Tropical rainforest trees often fruit heavily and are used by many species

    • They eat similar fruits but low competition cause there so many fruits

• Temporal isolation / speciation in resource use reduces comptition

  • E.g. Bats feed on fruits at night when frugivorous birds not active

  • Feathertail glider feeds on nectar at night; honeyeaters, butterflies, and friar birds feed during day

What are endemic species?

• Unique to a particular geographic region or locality

• Assumed to have evolved there

• Large number of endemic species in Australian tropical rainforest

• More endemic at higher altitude

• Separation of population = speciation

  • E.g. species ends up only existing on mountain tops = endemism (evolved there, not able to travel easily from that particular environment to somewhere else)

Rainforest endemics:

• There are more reptiles and frogs that are endemic than birds and mammals

E.g. Golden bower bird

• Occurs above 900m

• Feeds on fruit

• Smallest birds but males build largest bowers (to attract females)

  • Generations build on previous work

E.g. Boyd’s forest dragon

• Occurs in very dense rainforest areas: high and low altitude

• Don’t bask, and operate at lower temperatures to avoid pythons (except pregnant females)

• Use chemical signals of new growth (plants) that attract stick insect that they eat

E.g. Musky rat kangaroo

• Last of a Gondwanan group

• ~20 mill yr history

Conservation: Key issues for endemic rainforest species

• Limited distribution, often habitat specialists (loss of habitat or population = loss of that
  species world wide)

• Often rare & difficult to study, often little knowledge of biology

CS: Conservation of striped possums (rainforest)

• Quite common in PNG, not particularly common in Aus (Australia represents the edge of its range so it's quite rare as a species)

  • It is of conservation concern in Australia, not so much in PNG

Asking key ecological questions: What is their diet? What are their habitat use and area requirements? How do they compare to closely related species?

Finding answers: The link b/w what they eat and how much space they need = the idea of trophic levels and how energy moves through an ecosystem

• Bigger area = carnivorous (rather than herbivorous)

  • The metabolisms of most species are highly inefficient — about 90% of everything we eat is lost as thermal energy

  • They must find food across a wide area

Using known diets of other Petaurid (gliding) possums:

• Plant exudates (sap, gum, nectar) a major component of diet (major part)

• Smaller species supplement diet with invertebrate (minor part)

Looking at unusual morphological characters of Striped Possums:

• Klinorhynchy (rounded cranium)

  • suggests that potentially they're processing information — hunting requires thought and complexity

• Large procumbent lower incisors

  • Suggests they have a specialised diet

• Tongue & 4th finger elongated (similar to Aye-aye)

  • Suggests specialised diet of invertebrates

RESULTS: Striped possum diet: specialised insectivore

• Wood-boring beetle larvae and social insects very important in diet

• Other invertebrates taken opportunistically

• Plant exudates used occasionally

• The inverse of all of their cousins, where they're feeding mostly on insects and plant exudates are used occasionally

• Radio-tracking data showed that habitat requirements are huge compared to other petaurid possums

Key conservation issue of rainforests: loss of biodiversity

1. Habitat loss: extensive clearing of tropical rainforest is a direct threat to fauna

• 80% of Australian tropical rainforest is impacted by human activities, only 20% undisturbed = huge potential impact on fauna

• Disturbance creates ‘edges’ — opens up forest to invasion by weeds and feral species

• Rainforests can grow back but what grows back is of less quality

• Loss of components of habitat: E.g. Ulysses Butterfly - dependent on one plant genus for oviposition: Genus: Melicope, caterpillars feed on it’s leaves

2. Impact of increasing human population

• Human popns, development, and changed land management, along with continued traditional hunting

3. Poaching

• Wealthy animal collectors drive poaching of rare species for their private collections

4. Invasive species

• E.g. Yellow Crazy Ants

  • Can form super colonies and dominate the foraging spaces on ground

  • Incredibly aggressive, very effective at taking advantage of any food source they can find (outcompete)

• E.g. Wild pigs

  • Wallowing and other destructive behaviours = erosion and damage water sources

  • A vector for disease

5. Disease

• E.g. Sharp-Nosed Torrent Frog (G. Taudactylus) threatened by chytrid fungus

  • Damages the skin and impacts ability to keep infection out and gas exchange

• E.g. Spectacled Flying Fox (Pteropus conspiculatus) threatened by human activity, but also a reservoir for disease

  • More likely to spread pathogens when under stress(high cortisol suppresses immune system

  • Caused by humans: restrict their food sources, interrupt their habitat, stress them

  • Zoonoses: more likely to spread to humans

  • Bats tend to have long-standing relationships with diseases

Key conservation issue: loss of biodiversity = loss of functon

1. Seed dispersal:

• E.g. Bats (flying foxes)

  • If there is a big heat event coming through when the pups are still reliant on mum, they are quite vulnerable to heat

• E.g. Cassowaries

  • Feeds on fruit and disperses seeds

  • Large birds, thus can carry large seeds & a large volume of seeds

  • Large home ranges (smaller home ranges at lower altitudes)

  • Populations declining in many areas

• E.g. Musky rat kangaroo

  • Important seed dispersers in rainforest via scatter-hoarding (bury fruits and seeds but forget where they are)

  • Contribute to forest regeneration and ecosystem health

2. Nutrient recycling

• E.g. Insects i.e. termites

• E.g. Non-animal groups i.e. fungi

• Bulk of rainforest nutrients is in plants rather than soil (Australia's soil is low in N and P)

  • High productivity in these environments is because of rapid cycling of nutrients

Australia is the only continent with all 3 extant groups of mammals

1. Placentalia aka Eutherians (terrestrial / aquatic)

• “true” mammals

• Have a well-developed placenta that supports the young prior to birth

2. Monotremes

• Somewhat semi-reptilian in their habits

3. Marsupials (polyprotodont / diprotodont / ?)

• Pouched mammals

• The development of their young happens more outside of the body of the female

But Australia does not have very large extant native land mammals (compared to across the world: In Africa: elephants and giraffes or In Europe: bears and moose)

Characteristic of Class Mammalia

• Have hair (could just be whiskers)

• Females lactate (produce milk) to feed young

• Distinctive skeletal characteristics

• Endothermic

List the terrestrial eutherians of Australia

No large terrestrial eutherians in Australia, all are relatively recent arrivals

• Bats

  • microbats / insectivorous bats

  • megabats (e.g flying foxes - more dog-like face, good sense of smell, generally feed on blossoms, fruits, etc)

• Dingo (arrived pre-Europeans, present for 7000-10,000 years)

• Rodents: native rats & mice (approx. 56 extant spp. — make up the bulk in Australia)

List the marine eutherians of Australia

• Whales & dolphins

  • Humpback whales do a migration down to Antarctica (feeding) and back to Australia (breeding)

• Seals

• Dugongs

  • Range in the North of Australia

List the monotremes

• Platypus (1 species)

• Echidnas (4 species: 1 in Aus, others in PNG)

What makes monotremes different to other mammals?

Monotremes are mammals

• They have hair

• They lactate (produce milk but do not have teats — excrete milk straight out of skin)

But Monotremes are different to other mammals – have unique characters – some ancestral “reptilian” characters:

• Oviparous (lay eggs)

  • laid into a pouch (echidna) / burrow (platypus)

• Pectoral girdle and limbs “reptile-like”

  • Reptiles: fins became limbs that were out to the side

• Monotremes have electroreception (to locate prey)

  • Specialised sensors in bill

  • Detect very weak electrical fields (generated by muscle contraction in prey)

  • Platypus are foraging in murky river water, can’t really see (more effective / essential than in echidna)

Marsupials

2/3 of species found in Australia

• Australian marsupials are very diverse

  • different from South American marsupials

• Viviparous (live bearing)

  • But give birth very early (underdeveloped when outside the mothers body)

• Females carry young in their pouch

  • In the pouch is where most of growth happens

• Marsupials: 2 main groups

  • Polyprotodont (>1 pair of incisors, smaller)

    • Carnivores: Dasyurids i.e. Tas devil, Quoll, Planigale, Antechinus

    • Omnivores: Peramelids i.e. Bandicoots & bilbies

  • Diprotodont (1 pair of incisors, larger)

    • Herbivores or omnivores: E.g. Wombats, koala, possums, macropods (most diverse)

  • Polyprotodont / Diprotodont ??

    • Marsupial moles

      • Found in sandy deserts, arid central & western Australia (notoryctids)

      • Blind and deaf

      • Keratinized front of the face

      • Predators

      • Pouch faces backwards

When was megafauna extinction and what are the hypotheses?

• 50,000-20,000 ya (Late Pleistocene)

• Several hypotheses:

  • Climate change – increasing aridity

  • Habitat change by humans (fire)

    • Changes in the landscape

  • Over-hunting by humans

Recent mammalian extinctions

• Australia has a poor record of conserving smaller terrestrial sp. post European settlement (keeps increasing)

  • 39 species already extinct

  • many endangered 55

• Causes of extinctions

  • Introduced mammals (are serious pests)

    • Ecosystem degradation

      • Consuming vegetation, damaging vegetation / waterways

    • Competition with native species

      • Habitat, food source

    • Predators on native species

      • Predators hunting small mammals as well

  • E.g.

    • Cat & fox (+ dingo??)

    • Horse & donkey

    • Buffalo, pig, goat, deer & camel

    • European rats & house mouse

    • Rabbit & hare

CS: Analysing Dingo’s role in conservation and influencing landscapes

Role in conservation?

• There is persistence of smaller marsupials that have geographic overlap with dingos

• Dingos may partly “control” foxes and cats ? (especially in more arid areas)

  • Dingoes may suppress fox and feral cat populations through direct killing, competition and behavioural displacement (mesopredator suppression)

  • But it's not so simple as a clear r/s is not seen

Influencing landscapes

• Dingoes suppress the predators of small mammals

• Small mammals consume and reduce vegetation cover where dingoes are present

  • Shrub density is higher where dingoes excluded/absent because less small mammals

• Shrubs stabilise dunes (prevents dune movement)

The basics of mammalian reproduction

• Females mammals feed their young milk secreted by mammary glands

• The three mammal groups (monotremes, marsupials & eutherians) differ dramatically in their reproductive patterns + there is some variation in structure of the reproductive tract

  • However there is also variation WITHIN groups

• Generalised reproductive system in female mammals

Variation in female mammal reproductive tract structure

• Marsupial: urinary and reproductive tract are merged, digestive tract is separate

  • the urinary system and the reproductive system share the same opening but the rectum is separate

  • same opening for the birth of young and the excretion of urine

  • horned uterus, 2 functional ovaries, vaginal canal splits into three (medial and 2 lateral)

• Eutherian: urinary tract, reproductive tract, and digestive tract

• Monotreme: all 3 systems are merged and empty into the same exit point

  • Horned uterus

  • Platypus: co-evolution might have happened between the male and the female platypus such that the left-hand side of the reproductive system is more functional than the right

Variation in mammalian reproduction: Monotremes

• Lay eggs

  • Platypus 1-3 eggs: female remains in burrow after laying eggs (fasting) — has to thermoregulate and provide milk for young

  • Echidna 1 egg: laid into pouch, female remains active (foraging etc.)

• Eggs are small relative to reptile ancestors as reptiles do not lactate so must produce larger egg to nourish young

• Hatching: 10-14 days

• Pouch

  • Platypus: no

  • Echidna: yes

• Both species are seasonal breeders

• No teats (milk is secreted through pores)

• Lactation:

  • Platypus 3-4 months (faster development)

  • Echidna 6-7 months (slower development)

• Variations in behaviour

  • Echidnas:

    • Form a “mating train” – female at the front, males follow her around —> try to dig a rut and push female into it —> compete

    • Echidna penis is only to deliver sperm and compete with others, not for urine (they have cloaca)

    • After awhile, echidna young are left in burrow when they can thermoregulate & spines begin to form (puggle)

  • Platypus:

    • Have mating ritual in the water

    • Platypus females dig an extensive breeding burrow – up to 20m long

    • Female is stuck there until the young are big enough to thermoregulate for themselves

    • At emergence, platypus babies combined weight may be more than their mothers (a lot of energy input)

Variation in mammalian reproduction: marsupials

• Gestation in different sp.: 12-46 days

• Teat number & litter size varies considerably between and within species. Teats: 2 - 22

  • Koalas: 2 teats, generally only 1 young per breeding season

  • Antechinus: 6-10 teats (geographic variation within species), supernumerary young

• Pouch life varies: ~1 – 11 months

• Young after permanent pouch exit:

  • May be left in nest, mother returns to suckle young E.g. Antechinus

  • May be carried on back “back-young” E.g. Koala

  • May be “young-at-foot” accompanies mother E.g. Wombat

• Milk composition during lactation varies significantly

  • Massive span of growth and development that has to be supported by milk

  • Early:

    • tiny young

    • continuous sucking on the teat

    • mammary gland small

    • dilute milk (mainly carbohydrates — sugars for rapid growth and hormones for organ development)

  • Late:

    • larger (more developed) young

    • intermittent sucking (face unfuses from the teat)

    • mammary gland large

    • concentrated milk, higher in energy (including more protein & fats)

  • Some kangaroos & wallabies have simultaneous lactation!!

    • 2 different mammary glands produce 2 different types of milk (can support young at different stages of development at the same time)

• Embryonic diapause

  • Some female kangaroo/wallaby species can have 3 “young” at different stages at any one time: one blastocyst (fertilized), one in pouch - feeding on teat, one young-at-foot (almost weaned) - feeding on teat

  • Occurs in most macropods (kangaroos & wallabies), some small possums

Marsupials: Antechinus reproduction

• Male testosterone levels extremely high prior to and during breeding season

• Usually in their first year of life, males are aggressive

  • fight, constant mate-seeking behaviour until they stop feeding (usually winter)

• Prolonged and frequent copulation

• All males die from stress-related complications

  • Can have a short life span (die from high levels of testosterone, injured from competition)

• Males die before females give birth – no males in population for a period

• Males in captivity deprived of mating can survive much longer

Embryonic diapause — some marsupials and eutharians have

A period of stasis or lack of metabolic activity at the egg stage (an arrested blastocyst)

• Female can mate within a day of giving birth (already have young)

• But 2nd embryo development stops at blastocyst stage due to feedback of sucking stimulus of young already in pouch

• Embryo recommences development at weaning / death of older young (under hormone control due to no more sucking stimulus)

Occurs in most macropods (kangaroos & wallabies), some small possums, and some eutherians e.g. seals, bats

Variation in mammalian reproduction: eutharians

• Longer gestation, more advanced young at birth (compared to marsupials & monotremes), shorter lactation (relative to gestation)

  • However, there is much more variation in developmental stage of young at birth:

    • Active & running / swimming already

    • “Helpless” E.g. mouse, humans

• Milk composition is relatively constant during lactation

• Pattern is often:

  • large eutherian mammals = slow growing, long-lived, slow reproducing

  • small eutherian mammals = shorter lived, rapid reproduction, produce lots of young

  • But there are exceptions: Mega bat reproduction compared to other small eutherians

    • Generally long lived

    • Slower development, gestation longer (2 – 8 months)

    • Litter size small, slow reproduction: most bats 1 young/year

    • Form maternity colonies before giving birth

    • Large young – up to 30% of female weight!

    • Initially: mothers carry young, then leave them in nursery

    • Must locate own offspring among many others in the “nursery” at the colony

• Embryonic diapause

  • Some eutherians E.g. seals, bats

Marsupial vs eutherian placentation: both have a placenta during pregnancy

Eutherians: efficient allantoic placenta (hollow sac-like structure filled with clear fluid)

• Role: respiration, nutrition, excretion

Most marsupials: yolk-sac placenta

• Highly vascularised, but less efficient, however gestation very short

EXCEPTION: Peramelid marsupials (bandicoots): yolk-sac + allantoic form

• Starts of with yolk-sac placenta that turns into the allantoic form = more efficient / shorter gestation periods

Key difference b/w Monotremes &Marsupials vs Eutherians

Monotremes & Marsupials: lactation specialists (short gestation + long lactation)

Eutherians: gestation specialists (long gestation + short lactation)

Marsupial reproductive strategies have advantages:

• Some species can have multiple young at different stages of development at the same time

• Can stop investing in young early if environmental conditions deteriorate – thus overall lower energetic “cost” if they lose a young

• Some species have embryonic diapause – can restart reproduction quickly if environmental conditions become favourable

• Highly evolved character: variable milk composition throughout lactation

Birds evolutionary history

• F: Dromaeosaurid theropods (shared ancestor between birds & dinosaurs) e.g. velociraptor

• Birds are the result of the evolutionary lineage that gave rise to dinosaurs and continued with the feathered version

• Similar body morphologies: two hind legs, long forearms for reaching, movement in terms of the way they get around

• Birds are monophyletic, reptiles are paraphyletic

What are the types of phylogenies and what animal groups are examples for each?

A set of evolutionary relationships based on morphological, fossil and molecular data

• Monophyletic E.g. Mammals and birds

  • Originally based on morphology, but evolutionary molecular patterns for mammals happen to group nicely together - all the current examples of mammals share a common ancestor

• Paraphyletic: E.g. Reptiles

  • The current species that we have on the planet today don't all necessarily share a recent ancestor

  • In order to group them together and call them something different from everything else, bits of their evolutionary traits are left out

• Polyphyletic E.g. Algae

  • Useless in terms of trying to understand evolution

  • Across the algae, they've emerged mutiple times in very different evolutionary history

    • Some are single-cells, some of them are huge multi-celled structures. Only thing in common is that they're all photosynthetic, and they're not plants

What was the oldest known fossil bird (genus)?

Archaeopteryx 147MY (Jurassic)

• Theropod dinosaur with flight feathers

• “Missing link” between dinosaurs and birds

  • Maintain a lot of reptilian characters (not in birds anymore): long bony tail with all the vertebrae extending out beyond the body, jaws with teeth, claws at the ends of limbs

  • But has feathers, and flight is supported

Advantages of flight

• Air - unexploited habitat / niche

• Abundance of prey (flying insects)

• Escape from terrestrial predators

• Allows wide and fast travel

• Migration – access to year-round favourable climate and resources

What were the hypotheses of what drove the evolution of flight?

Wings evolved from forelimbs (arms)

1. Ground Up (most plausible explanation based on Archaeopteryx body form)

   • Wings evolved from arms used to capture small prey

   • Wings evolved because bipedal animals were leaping into the air; large wings (forelimbs) assisted leaping

2. Trees Down

   • Wings evolved from gliding ancestors that began to flap their gliding structures in order to produce thrust (individuals with better wings “selected”)

3. Sexual selection

   • Wings were used as sexual display structures: bigger wings were preferred by potential mates

Australian bird fossils

• Birds make poor fossils - small delicate bones

• 110 MYA fossil feathers from Koonwarra, Vic

  • very similar to feathers in present (feather structure hasn’t changed much)

• 30 MYA penguin fossils & F:Dromornithidae tracks suggest moving in flocks

• 20 MYA extensive fossils of wetland birds in Central Australia (once supported wetter environments)

F:Dromornithidae — Dromornis stirtoni aka “Stirton’s Thunder Bird” or the Demon Duck of Doom

• Central Australia 15 mya

• Flightless, weight 500+ kg, 3m tall

• Related to geese (also flock)

• Most likely not predators

  • Beak and toenails not hooked / necessarily evolved for predatory behaviours (tearing open, holding prey down)

• Diet: vegetarian (based on a.a. in eggshell)

F:Dromornithidae — Genyornis newtoni: present in Australia until approx 50,000 ya

• Rapid extinction due to climate change or overhunting

Characters that define birds

• Feathers

• Wings (but not all can fly, some are secondarily terrestrial or amphibious)

• Very light (reduced weight), very strong skeleton, bones hollow

• Beak (no teeth) - could be for weight loss

• Lay hard-shelled eggs (oviparous)

• Endothermic

Modern birds: what class and subclasses?

Class: Aves

2 subclasses: Paleognathae (ratites) & Neognathae (everything else)

• Neognathae i.e. O: Passeriformes (passerines) = “perching birds”/song birds.

  • contains approx ½ worlds sp.

  • most diverse & widespread (global)

  • Gondwanan origins: evolved in Australia 54mya

• Non-passerines: 34 Orders (21 orders in Australia)

  • some gondwanan, some not

Diversity worldwide and in Australia

Diversity worldwide (class Aves)

• Approximately 10,000 living species (more species than any other vertebrate group except fishes)

• From 1.8g to 160 kg

Diversity in Australia (including offshore islands)

• about 898 species

• 45% are endemic

• Largest: Cassowary

• Smallest: Weebill

Convergent evolution: Many Australian species resemble northern hemisphere spp.

The selection pressures that have happened in that particular region, has meant that there are similar sorts of animals evolving over time even though not related

E.g. English robins and Australian robins

E.g. English wren and Australian wren

E.g. Northern hem nuthatch and Australian Sitella

• Both got beaks evolved for digging insects out from under bark

• Both have similar body movement in that they hop up and down the tree, the tree trunks, hunting for insects

• Both have similar couring

• DNA studies allow origin and evolution to be unravelled

  • Proves that these Australian birds are not derived from northern hemisphere stock - more closely related to each other than to their N.H. “look-alikes”

Diversity: 5 broad categories of Australian birds

Non-phylogenetically accurate, but convenient groups

1. Long-established non-passerines of Gondwanan origin

2. Australasian passerines (perching/song birds)

   • Distributions extend to Asia

3. Recent colonists from Eurasia

   • Aus birds radiated out ~50 mya, and then over time species returned to Aus

4. Introduced species

5. Worldwide groups

Australian birds: 1. Long-established non-passerines of Gondwanan origin

a) Ratites - emu & cassowary: flightless, bulky

• Emu: adapted for long distance out on the plains, lean body form

• Cassowary: rainforest adapted (highly nutritious, productive environment), very solid, stocky body form

• World distribution of ratites (Gondwanan): good evidence of plate tectonics and the separation of continents away from Gondwana over time

  • Tinamous can fly, rest are flightless

  • Since they are flightless, they could not easily cross oceans to colonise other continents — isolated popn evolve

• Tiniest ratite: Kiwis – 5 species, smallest only 1.2 kg, only present in NZ

b) Parrots

• 332 spp, mostly Southern Hemisphere

  • 88 Australasian endemics

  • 54 spp. in Australia

• 2 groups

  • F: Cacatuidae — Cockatoos (endemic Aust & Sth E Asia)

  • F: Psittaculidae — Old World Parrots

Parrot characteristics:

• Very strong curved beak (good at breaking open)

  • feed on cones, seeds, fruit, nectar

• Strong legs & claws (zygodactyl foot - 2 toes at the back, 2 at the front)

  • can manipulate food

• Most are brightly coloured & often lack sexual dimorphism

• Occur in all habitat types (from Taz to tropics)

• Most nest in tree hollows

• Many are long-lived e.g. Palm cockatoo

  • Some are struggling with loss of habitat and predation

Parrots diversity of ecology and distribution:

• many species form flocks

• many species pair – monogamy

• habitats: rainforest, woodlands mallee, arid zone, etc.

• some sp. make long range movements to escape drought

• Some species have very broad distributions, others are very restricted

Threats:

• Habitat fragmentation & loss e.g. loss of food trees, loss of tree hollows for nesting

• Illegal trade/harvest

*Not universal threats for all species, some species are widespread, abundant & populations are expanding

c) Penguins

• World total: 17 species

  • Most in subantarctic

  • 1 in Australia

• Southern hemisphere distribution

  • further south = colder = bigger penguins

Australian birds: 2. Australasian passerines (perching/song birds)

• Most recently evolved group of birds

• Australians passerines: magpies, fairy-wrens, honeyeaters

• ‘Corvid’ passerines: includes crows, ravens

The broader family of corvids originally evolved in the Australian region (part of ancient Gondwana), spread outward to Asia and other parts of the world, and later the specific Corvus genus (crows and ravens) re-entered Australia from Asia in relatively recent geological prehistory

Australian birds: 3. Recent colonists from Eurasia

Of ‘Asian origin’ — Families that ‘recently’ colonised Australia and now breed here (i.e. established & “native”)

• Swallows, larks, cisticolas, some raptors - taxonomically mixed (some gondwanan origin, some introduced)

Australian birds: 4. Introduced species

• E.g. Starling, blackbird, Indian mynah

• Deliberate introductions by humans (Europeans), now are pest species

Australian birds: 5. Worldwide groups

• Long-distance flight capabilities

• Strong powers of dispersal

Raptors (birds of prey)

• Diurnal - eagles, kites, falcons etc. (but no vultures or secretary birds in Oz)

• Nocturnal - owls, nightjars & frogmouths

Seabirds and shorebirds

• Retain a regular migration pattern

  • distribution is global because they move from N to S hemisphere every year

• Species with strong powers of dispersal

  • E.g. Red knot

    • Annual migratory sp.

    • Nest in northern hemisphere (Arctic Circle), migrate away from northern winter each year to Australia, Indonesia, and NZ

    • Have various points (coastal wetlands) to land and refuel

Bird mating systems

There is usually a strong association between mating system and level of parental care

• Monogamy

• Polygyny (male ← many females)

• Polyandry (female ← many males)

• Promiscuity (multiple matings)

Bird mating: Monogamy

• One male mates with one female

• Pair bond lasts for b/w one season to a lifetime (varies in different sp.)

• Pair mate, incubate and raise chicks together (shared effort) — a lot of courting rituals and establishing r/s

• Most widespread pattern in birds

• Monogamy is social, not necessarily genetic

E.g. Albatross (social & genetic)

• Can live up to 50 years

• Lifelong pair bond

• Single chick takes up to 280 days to reach independence

• Parents take turns to undertake long foraging trips

• High demands of chick rearing favours evolution of monogamy

E.g. Black Swans (social)

• Males and females pair for life

  • they are social pairs — swim together, build a nest together, and raise offspring together

    • BUT may not be genetically/sexually monogamous

    • about 15% (1 in 6) cygnets (baby swans) are ‘illegitimate’

• Can form heterosexual pairings and homosexual pairings

  • About 25% of the pairings in a population of swans will be male-male

    • Tend to have a high success rate of raising young of about 80% in terms of getting them to survival and independence (compared to about 30% for most heterosexual pairings)

E.g. Fairy-wrens (social)

• Males & females pair for life (~13-14 yrs)

• Both parents care for young

• Philandering

• Males show a variety of adaptations for ‘extra-pair’ mating

• Females are trying to keep each other out of each other's territories, meanwhile the males are trying to sneak into each other's territory

• 76% of all offspring are ‘illegitimate’

Bird mating: Polygyny

• 1 male mates with several females

• Sexual dimorphism is common

  • Males often exhibit courtship and have elaborate colouration compared to females E.g. riflebirds

  • OR males build structures for courtship

• Generally no male contribution to care (building nest, feeding, incubation)

E.g. Satin bowerbird

• Males build ‘avenue bowers’ and decorate them with blue objects

• Females tour bowers during the breeding season

• Females decide whether or not to mate after judging bower - “mate choice”

• Female builds nest & raises young alone - polygyny

Bird mating: Polyandry

• 1 female mates with several males

• Separate clutches for each male (into nest that he has built)

• May be ‘successive’ or ‘simultaneous’

  • successive: there is a break in time before next mating

  • simultaneous: 3-4 clutches of eggs being laid in a short window of time for different males, all being raised in parallel

• Male raises offspring (incubating and raising young)

  • Various ways in which they care for young

E.g. Painted snipe

E.g. Comb-breasted jacana

E.g. Southern cassowary

• Successive polyandry

• Female lays for up to 3 males

• Male incubates 2 months

• Extended male care: 9 months

Forms of parental care in birds

1. Bi-parental

2. Paternal or maternal

3. Mound-builders (care during incubation, no care after they hatch)

4. Cooperative breeders (the whole family)

5. No care (inter/intra-specific brood parasites)

Bird parental care: Bi-parental care

E.g. Little penguins

• Monogamy

• Even when laid days apart, they hatch at the same time (synchronous hatching)

• Chicks are raised in underground burrow

• Chicks are usually big

• Male and female alternate shifts during incubation and feeding

Bird parental care: Paternal care

E.g. Emus

• Successive polyandry

• Male builds nest (2m diam.)

• Female lays 5-15 eggs

• Male incubates clutch for 55 continuous days

• Male continues to care for young for up to 6 months

• If egg falls out of nest space, male does not recognise it as its young anymore :(

Bird parental care: Mound builders

Build big structures (out of soil, sticks, vegetation, etc.) that has internal heat generation process to incubate the eggs

• There is rotting vegetation and organic matter inside the mound that produces heat like a compost bin which supports the right temperature to get those eggs to germinate

E.g. Malleefowl

• Eggs laid inside a mound built by both parents

• Rotting process generates heat —> incubates eggs

• Male maintains mound @33°C (checks temperature with tongue many times a day)

• Chicks independent at hatching (they have to dig their way out themselves, no further care from parents)

Bird parental care: Cooperative breeding

• Breeding pair assisted by ‘helpers’ in the care of young

  • Helpers are usually grown offspring from previous broods

• Quite common in Aus birds

• Helps with territory defence, incubation and nestling feeding (helps find food, particularly if that food is invertebrates or things that they must hunt a little bit further for)

• Altruistic behaviour?

Why helpers stay:

• Shortage of breeding territories and/or mates
  forces offspring to stay at home

• Possible benefits:

  • gain breeding experience (and possibly matings)

  • indirectly pass on ‘own’ genes by helping parents raise more brothers and sisters (they are related)

E.g. Choughs E.g. Apostlebirds

• Live in groups of 2-20 individuals - highly social

  • small groups are not as successful as raising young, the bigger the better

• Difficult foraging niche (sub-surface invertebrates)

• Slow transition to independence for young

• Acute dependence on helpers (cooperative extremes):

  • nesting pairs and trios always fail

  • groups may try to kidnap helpers (raid other flocks)

Bird parental care: No parental care

• Inter-specific brood parasitism

  • female drops eggs into nests of a different “host” sp.

  • E.g. Cuckoos

• Intra-specific brood parasitism

  • female lays some eggs into nests of the same sp.

  • E.g. Swallows E.g. Coots etc. (but females will also have own nest)

E.g. Australian cuckoos (inter-specific)

• Cuckoo adds an egg to the clutch of the ‘host’

• Cuckoo chick develops more quickly and hatches earlier than host chicks

  • Requires more food than host chicks

  • Instead of 3 chicks, there is just one cuckoo

• Cuckoo chick ejects the host eggs & is fed by host

• Selected for producing eggs that either the eggs mimic that of the host or when the chicks hatch they look very similar to the host's chicks

E.g. Canny cuckoos and wily wrens (inter-specific) — an evolutionary ‘war’

• Horsfield’s bronze cuckoo lays a mimetic egg that tricks fairy-wren into accepting it

• In response, fairy-wrens have learned to recognise and reject chicks

What are 2 main functions of bird song, and what forms of Australian bird vocalisation are there?

1. Territory defence

2. Mate attraction (mostly males sing)

Australian themes:

• Duets

• Female song

• Vocal mimicry