Lecture 13- Animal adaptations to extreme environments: Alpine Zones

Question 1

What is the torpor in mammals like?

Answer 1

• MR at 1/20 - 1/100 normal, thus saves energy • exit torpor by turning MR up, body temperature follows, the signals are not understood, the ones triggering the MR up • can be short-term or long-term depending on food availability -some animals can drop down to 5 degrees

Question 2

What is torpor like in small marsupials?

Answer 2

-measure by oxygen consumption, if it drops then the metabollic rate drops -

often do test drops

• this one is nocturnal and goes into torpor during the day
• must be in a safe place when in torpor

Question 3

What is hibernation?

Answer 3

-similar to torpor -Seasonally-induced deep torpor, longer bouts -Only two Australian mammals: - 1.Mountain pygmy-possum - 2. Echidna -Fatten-up prior to winter, really important, must have minimum amount of energy left to leave hibernation so if too low on energy will not go into torpor -Hibernaculum (safe place) -Test drops in body temp -Periodic arousal= about getting rid off waste products

Question 4

What is a hibernaculum?

Answer 4

-safe place to be during hibernation

Question 5

How do ectotherms fare in the alpine zone?

Answer 5

• Lower energy requirements – useful in an energy poor environment which is an advantage • However Tb declines with environmental temperatures, thus can’t maintain activity • Straetgies to avoid freezing?? - dormant life stage - seek refuge (like under the snow) - migrate -so have a combination of strategies to avoid freezing

Question 6

What are the invertebrate adaptations to temperature fluctuations?

Answer 6

• Small size (hypolithy - occupy sheltered micro- climates e.g. under rocks) • Stenothermy (physiology geared to operate at low temps thus sensitive to heat) • Reduced wings (flying difficult in high winds)

Question 7

How does the Tasmanian scorpionfly deal with low biological productivity in the alpine zone?

Answer 7

Tasmanian scorpionfly (Apteropanorpa tasmanica) In spring and summer, 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)

Question 8

What is the behavioural thermoregulation in invertebrates?

Answer 8

-Chameleon grasshopper (Kosciuscola tristis) is a good example -Remain active all day (can cope with temperature extremes) -Movement in & out of sun -Thermal melanism: - in cold conditions (higher altitude) darker/black, thus absorb heat - in warmer conditions (lower altitude) – paler blue or green i.e. ectotherms, but use behaviour & melanism to raise body temp via sun

Question 9

How do the grasshoppers change colour?

Answer 9

-in temperatures above 25 degrees they become paler -pigment granules migrate in and out of the epidermal layer depending on the temperature

Question 10

How do frogs do in alpine zone?

Answer 10

-Frogs are also in the alpine zone!! eg: Corroboree frog= don’t jump, Baw Baw frog • Over-winter in alpine areas (low mobility) • Become totally inactive during cold temperature, must be in safe habitat • Must find microhabitats that don’t freeze -must have running water somewhere

Question 11

What are the characteristics of Coroboree frogs?

Answer 11

• Occur mainly over 1800m elevation • Males dig burrow in sphagnum moss bogs & call • Females lay in this nest • Eggs hatch, but development is delayed until winter, then slow. When burrows fill with water in spring they mature -female frogs don’t sing, at all ever

Question 12

Where do the Corroboree frogs occur?

Answer 12

• limited and fragmented areas
• also because sphagnum moss is highly impacted by fire
• very rare and declining already

Question 13

What are breeding patterns like in alpine zone animals?

Answer 13

•Short period of warmer weather, thus short growing season & short breeding season, but very predictable (unlike in arid zone) typically growing season is short and must get ready for the cold, very tightly synchronised breeding pattern •Some species exhibit dormancy at other times of year (i.e. 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 - synchronised breeding season, fast growth etc. -invertebrates usually breed much faster than vertebrates

Question 14

What is the breeding pattern of the mountain pygmy possum?

Answer 14

-highly seasonal - Entirely limited to alpine regions, - Thought extinct until 1966, endangered - 30 to 80g & lives 5 – 12 (?) years - Habitat: boulder fields and rock screes, live under them and move under snow in winter - Hibernates up to 7 months/yr, they fatten up a lot before hibernation - Diet: arthropods, fruit, seeds & caches food - Mating occurs when snow melts and Bogong moths arrive (store body fat) - “Tunnel of love” - sexes occupy different habitats -females only live upslope and males only live downslope, so they engineered the tunnel of love so could -ski runs are an issue as they tamped down the snow and the animals cannot move underneath

Question 15

What is the breeding pattern of the Bogong moth?

Answer 15

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

• Larvae winter in pastures in Sth QLD, NSW & SE Vic, but food plants dry 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
• very successful and in vast numbers in Australia -very good source of food as are very fatty

Question 16

What is the connection between aboriginal people and the bogong moths?

Answer 16

• Bogong moths “extremely nice and sweet, with a flavour of walnut, so much so that I desired to have another feed” •Local Aboriginal people moved up into alps for 2-3 months in warmer weather - congregations of 500-700 people - gatherings broke down tribal barriers/resolved issues •Recorded that: people went up thin after winter & came down in good physical health= thanks to the bogong moths

Question 17

How does the climate change impact the alpine zone?

Answer 17

•Distribution of alpine plants and animals is very restricted - to zone between tree-line and summit • As the continent warms, animals will have to move higher to access preferred conditions so it will be even smaller than it is now • Australia’s mountains are relatively low: climate change may leave specialised alpine species with nowhere to go

Question 18

What are the changes in the alpine zone due to climate change already?

Answer 18

• Tree-line at Mt Hothamin Victoria has already moved up 40m to an area that had not had trees for past 25 years, so the area is already shirinking • Expected18-66%reductionin snow cover by 2030 and 39-96% by 2070 • With small change in temp,tops of six mountains will be the only remaining alpine ecosystems

Question 19

What are the effects of climate change on the pygmy possum?

Answer 19

•Less than 500 individuals of Burramys parvus remain on Kosciuszko •Climate change is likely to threaten survival because Burramys needs 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

Question 20

What are some other conservation issues for alpine areas?

Answer 20

• Extensive recreational use • Human infrastructure: loss of habitat, erosion, pollution etc • Increasing frequency of fire • Cattle and sheep (grazing and trampling) • Feral animals – rabbits cats, brumbies

Question 21

Summary:

Answer 21

• Small area of Australia • Extreme fluctuations in temperature • Low productivity environment - energy input from outside is important • Invertebrates: variety of strategies • Endotherms: leave,hibernate or cope • Many specialised species at risk from climate change • +other,more general, conservation threats

Question 22

What is the alpine zone?

Answer 22

the area between nival zone and the tree line

Question 23

How much of the australian landmass is alpine zone?

Answer 23

• 0.15% -total of alpine area of Australia, highly fragmented cannot migrate between , naturally fragmented by low altitude
• tasmania is at lower altitude as is more south

Question 24

What is the mean temp. of the warmest month in the alpine zone?

Answer 24

-below 10 C so trees don’t grow here, only bushes -but strong winds make it feel much colder

Question 25

How long do we have snow in the alpine zone in Australia?

Answer 25

• 2-3 months a year

Question 26

How much of Australia’s rainfall falls in the alpine zone?

Answer 26

-25%

Question 27

What is the alpine areas significant for?

Answer 27

water supply, recreation, nature conservation (contains unique group of native species)

Question 28

What are the special features of the alpine environment?

Answer 28

-predictable, strongly seasonal • Extreme temperature differences • Prolonged cold - winter, night and cloud • Abundant moisture - condensation, snow melt • Flora mostly herbs and lichens - very low biological productivity • Snow gums (sub-alpine woodlands) • Energy input through flying insects, wind-blown pollen and seeds (so from outside)

Question 29

What is the alpine zone flora like?

Answer 29

-small plants, summer flowering -e.g. alpine grasses, peat bog and streams (permanent water) and alpine daisies

Question 30

What are the characteristics of the snow gums?

Answer 30

-sub alpine -• Leaves can withstand freezing (waxy) • Do not occur on mountaintops (not in alpine zone) • Highly susceptible to fire

Question 31

What is the australian alpine zona fauna like?

Answer 31

• Low species diversity • Fewer species present as altitude increases • No truly alpine birds - migrate seasonally e.g. flame robin • Low diversity of reptiles (only 1 species found over 2000m in altitude) • Very few mammals, large herbivores absent • Invertebrates most diverse and abundant group • Food availability highly seasonal

Question 32

What are endotherms?

Answer 32

endotherms generate their own body heat via metabolism (i.e. maintain Tb) – but very energetically expensive - mostly mammals and birds (but also some invertebrates)

Question 33

How do alpine endotherms behave?

Answer 33

• Some sp. stay active • Many sp. avoid cold by migrating - e.g. birds, large mammals (wallabies) • Some use torpor - e.g. small mammals

Question 34

How do wombats fare in the alpine zone?

Answer 34

• active during winter - medium body size - mammals, thus high MR so can keep warm -around 20kg, so resistant to cold -high metabolic rate when foraging so can stay warm -more round so don’t lose heat as much -can dig to remove snow to find food, so burrowing is an advantage in alpine areas

Question 35

What is torpor?

Answer 35

– daily adaptive hypothermia • Body temperature drops dramatically • Reduced metabolic rate, respiratory rate, heart rate, body temp • Curl up (minimise surface area) • Often a response to low food availability • Very important in seasonal and low productivity habitats • Small endotherms – never more than a few hours from starvation • Occurs in species where adults <10kg • Common among small marsupials • Energy-saving strategy

Question 36

What is the typical pattern of torpor in small mammals?

Answer 36

Rapid entry

• metabolic rate (MR) drops, body temp drops by passive cooling.
• red: body temp
• black: ambient temp