Lecture 13: Arctic animals

Question 1

Abisko =

Answer 1

• location
• 200km north of arctic circle
• forest/dwarf heath ecosystems
• winter = freezing, rivers freeze over, lakes 1m deep in ice, 1m of snow

Question 2

The north atlantic oscillation (NAO)

Answer 2

• change in pressure difference between Azores high and Iceland low
• warm air into northern Fennoscandia
• frequency has been changing, BUT in recent years always positive
• correlation with climate change

Question 3

POSITIVE The north atlantic oscillation (NAO) causes =

Answer 3

bodies of warm air to be pushed in periodically,

• causes rain on top of snow forming ice layer within the snow
• encase the vegetation in ice (animals find it difficult to access it)
• changes nature of snow pack
• winter warming events, warm air over snow, snow melts, plants falsely triggered into growth = frost damage

Question 4

Red Deer (Cervus elaphus) The north atlantic oscillation (NAO) effect

Answer 4

• sub arctic species

- population strongly effected by NAO

Question 5

Red Deer (Cervus elaphus) The north atlantic oscillation (NAO) effect DEER LIFE CYCLE

Answer 5

MALES
- grow antlers in summer, shed velvet in august, regain condition in winter, cast antlers in spring

• FEMALES
• RUT in autumn, pregnant over winter, calving in spring, lactation in summer

Question 6

Red Deer (Cervus elaphus) + The north atlantic oscillation (NAO) effect: WHAT HAPPENDS

Answer 6

• strong (+) NAO effects flowering date, = early flowering
• early flowering = more calves are produced
• ## how warm the spring with correlated w NAO effect deer population

Question 7

Reindeer Rangifera tarandis Found where & lives

Answer 7

• northern Fennoscandia
• herded by people
• vital resource for Arctic people
• a major control of arctic vegetation
• population fluctuates but not increasing

Question 8

Reindeer pastoralism =

Answer 8

• spring they’re moved to calving land

LOOK AT SLIDES AND COPY

Question 9

___ is the limiting season for the reindeer population & NAO effect

Answer 9

WINTER

• food supply is limited
• must dig through the snow to access lichens and other vegetation
• NAO effect = rain on snow, cant access veg, if veg trapped in ice cant access

Question 10

reindeer and red deer populations effect the same by NAO

Answer 10

no, red deer increase, reindeer decrease

Question 11

Natural reindeer populations

Answer 11

• In north america, migrate according to natural cues
• calving is coincided w maximum resource availability
• climate warming advances plant phenology
• migration triggered by day length not temp
• they move too late, TROPHIC MISMATCH
• miss max vegetation
• the greater the trophic mismatch = population goes down (increases calf mortality and decreases fecundity)

Question 12

TROPHIC MISMATCH example

Answer 12

natural reindeer migration

Question 13

Lemmings (Lemmus lemmus)

Answer 13

• sensitive to snow conditions
• in winter live in the subnivian interface between snow and ground (between veg & ice pack)
• good snow conditions are the major factor enabling population booms
• predators also regulate population fluctuations

Question 14

Lemmings populations & NAO

Answer 14

• prior to 1990 lemming typical boom-bust
• in 90’s no boom-bust, populations stay low
• correlation between increasing NAO and population of lemming = due to nature of the snow
• ice formation in snow and ice encasement of their food
• – restricts access to subnivian location and food
• knock on effect to their predators and leads them to eat others i.e. birds