ZOO 4910 Lecture Notes - Lecture 18: Permafrost, Thermoregulation, Marbled Salamander
2 May 2018
School
Department
Course
Professor
Evidence: Global sea ice area has drastically decreased (2017
was lowest year)
Acidification
○
Warming
○
Atmospheric carbon
•
Melting (sea ice, glacial, permafrost)
○
Drought
○
Fire
○
Disease dynamics
○
Warming
•
Flooding
○
Fire
○
Drought
○
Extreme/Unpredictable weather
•
Ecological Effects:
--> habitat loss (rising sea levels, decreasing lake
levels, melting ice, fire)
•
--> disease thriving in warm or wet environments (ex.
Ticks, fungi, thermoregulation)
•
E.g. Warming airs and water
If current warming trends continue, estimated overall
extinction risk in 1/6 animal species by end of the
century
•
Using fossil record as a predictive tool
○
Range size
○
Taxonomic group
○
Biodiversity bias: more species --> greater
chance of these species to go extinct
!
Tropics are especially vulnerable (consider bias
in diversity)
○
Intrinsic extinction risk is predicted from fossil record
(23 million years) of marine genera and combined with
rates of anthropogenic threat (+ climate velocity)
•
Highest in South America (25%)
○
Australia (20%)
○
Africa & marine (15%)
○
Asia (5%)
○
North America & Europe (0-5%)
○
Based on regions:
•
Climate change and extinction risk:
Marbled salamander is increasing distribution
and range in response to warming winter
temperatures
○
Local populations of spiny lizards are going
extinct in response to competition due to range
shifts
○
Since 1975, 12% of local populations are
extinct, 4% worldwide
!
Local extinctions projected to reach 39%
and species extinctions to reach 20%
!
Historical analysis of 48 species at 200 sites in
Mexico:
○
Erosion of lizard diversity by climate change and
altered thermal niches
•
Competitive exclusion can limited ability
for species to move
!
Species shift to more favourable environments1.
Constrained by physiology
□
Behavioural plasticity
!
Constrained by genetic trade-offs
(i.e. growth)
□
Adaptation (evolution)
!
*especially in marine/aquatic
environments
!
Constrained by upper limit of
critical temperature for function
(CTmax)
□
Physiological plasticity
!
Species adjust to new environments via:2.
Two options for response to climate change:
•
Not always predictable and must include
comprehensive analysis of ecological factors
○
Opposite to what one would predict
!
Birch forests (breeding habitats)
□
Reasoning: complex ecosystem changes
!
Ex. Montane birds shift downslope despite
recent warming in the northern Appalachian
Mountains
○
Range shifts:
•
Q10 = rate of change of a biological system with
change in temperature
○
The higher the Q10, the greater the effect of
warmer climate on physiology
○
The current lack of a comprehensive
analysis of the capacity for physiological
plasticity across taxonomic groups and
geographic regions, constrains predictions
of the impacts of climate change
!
Acclimation decreases Q10
!
Q10 (thermal sensitivity) is highest
in acute
□
More protected from
dire changes in
temperature
◊
Closer to equator --> less
effect on Q10
!
Post-acclimation Q10 increased with
latitude (higher in marine?)
□
Increase in physiological rates with
increased temperature was less when
animals had opportunity to
acclimate
□
With opportunity to acclimate,
physiological rates of animals from
low latitudes were less affected
□
Results:
!
Physiological plasticity increases resilience of
ectotherms to climate change
○
Physiological plasticity:
•
Liver's ability to metabolize toxins
decreases with increasing temperature
!
Ex. Ambient temperature influences tolerance to
plant secondary compounds in a mammalian
herbivore (desert woodrat)
○
Physiological constraints:
•
Aggressive and bold behavioural
style
□
Rigid and routine-like behavioural
flexibility
□
Low stress responses (GCs)
□
Less sensitive to changes in
immediate environment
□
Less able to cope with
environmental change
□
More fit in constant/predictable
environment
□
--> "proactive"
!
Cautious/shy behavioural style
□
Flexible behaviour
□
High stress responses (GCs)
□
More sensitive to changes in
immediate environment
□
More able to cope with
environmental change
□
More fit in changing/unpredictable
environment
□
--> "reactive"
!
Stimulus --> perception --> personality
○
Success of individuals may be variable -->
differential fitness based on environment
○
Behavioural plasticity:
•
Unexpected cold weather during calving =
increased glucocorticoids
!
Increased glucocorticoids = disrupted
microbiome, susceptibility to infection
!
Pasteurella (typically harmless gut
microbe in small quantities) is a likely
culprit
!
70% of world's Saiga antelopes were dead within
2 weeks in spring of 2015
○
Stress physiology:
•
Responses to Climate Change
Explains fitness variation in a population by the
timing of breeding of the focal species and the
timing of species at the immediate lower level
○
Can occur at multiple trophic levels
!
Some species have greater plasticity in
response to abiotic cues
!
As temperature warms, phenology of
temperature-dependent processes advances
!
Study completed involved tits
○
Match/Mismatch Hypothesis:
•
Caterpillar abundance is matched to chick
rearing (due to sunlight)
○
Increased temperatures advance caterpillar
emergence (due to increased temperature) -->
mismatch abundance with rearing
○
Ex. In song bird species
•
Widespread implications for migratory animals
due to mismatch between cues on wintering
grounds vs. environment on breeding grounds
○
Temperature predicted to increase more rapidly near
the poles (~3.5 degrees in boreal forest region by late
century)
•
Naval base wallabies (need light) are mating
later in the season compared to bush
wallabies --> decrease in fitness
○
Ex. Artificial light at night desynchronizes strictly
seasonal reproduction in a wild mammal
•
Phenological Mismatch:
Age of sea ice (not as cold) has also decreased
○
Behavioural plasticity: shifting food
sources, storing food
!
Physiological plasticity: "walking torpor"
!
--> collapse of seal populations
!
*directly related to polar bear success
○
Average monthly arctic sea ice extent has dramatically
decreased since 1978
•
Prey upon and outcompete Arctic fox for
lemmings
○
Warming winters allow red fox to expand northward
•
Coat change species are typically found in
the north
!
Colour changes from white to brown in
circumpolar species
○
Clock genes turned to day-length program
seasonal moult
○
Due to shorter winter, have white coat
when snow has already melted (shorter
snow cover period) --> colour mismatch
!
Natural selection over time to adapt for
phenological mismatch
○
Rub selves into dirt to cover white
coat after snow has melted
□
Adapt to environment without time
for natural selection to occur
□
Ex. In rock ptarmigan
!
More immediate adaptation: behavioural
plasticity
○
Colour mismatch:
•
Climate Change in the Arctic:
Climate Change on
Vertebrate Biology
Wednesday,+ November+ 29,+2017
12:35+PM
Evidence: Global sea ice area has drastically decreased (2017
was lowest year)
Acidification
○
Warming
○
Atmospheric carbon
•
Melting (sea ice, glacial, permafrost)
○
Drought
○
Fire
○
Disease dynamics
○
Warming
•
Flooding
○
Fire
○
Drought
○
Extreme/Unpredictable weather
•
Ecological Effects:
--> habitat loss (rising sea levels, decreasing lake
levels, melting ice, fire)
•
--> disease thriving in warm or wet environments (ex.
Ticks, fungi, thermoregulation)
•
E.g. Warming airs and water
If current warming trends continue, estimated overall
extinction risk in 1/6 animal species by end of the
century
•
Using fossil record as a predictive tool
○
Range size
○
Taxonomic group
○
Biodiversity bias: more species --> greater
chance of these species to go extinct
!
Tropics are especially vulnerable (consider bias
in diversity)
○
Intrinsic extinction risk is predicted from fossil record
(23 million years) of marine genera and combined with
rates of anthropogenic threat (+ climate velocity)
•
Highest in South America (25%)
○
Australia (20%)
○
Africa & marine (15%)
○
Asia (5%)
○
North America & Europe (0-5%)
○
Based on regions:
•
Climate change and extinction risk:
Marbled salamander is increasing distribution
and range in response to warming winter
temperatures
○
Local populations of spiny lizards are going
extinct in response to competition due to range
shifts
○
Since 1975, 12% of local populations are
extinct, 4% worldwide
!
Local extinctions projected to reach 39%
and species extinctions to reach 20%
!
Historical analysis of 48 species at 200 sites in
Mexico:
○
Erosion of lizard diversity by climate change and
altered thermal niches
•
Competitive exclusion can limited ability
for species to move
!
Species shift to more favourable environments1.
Constrained by physiology
□
Behavioural plasticity
!
Constrained by genetic trade-offs
(i.e. growth)
□
Adaptation (evolution)
!
*especially in marine/aquatic
environments
!
Constrained by upper limit of
critical temperature for function
(CTmax)
□
Physiological plasticity
!
Species adjust to new environments via:2.
Two options for response to climate change:
•
Not always predictable and must include
comprehensive analysis of ecological factors
○
Opposite to what one would predict
!
Birch forests (breeding habitats)
□
Reasoning: complex ecosystem changes
!
Ex. Montane birds shift downslope despite
recent warming in the northern Appalachian
Mountains
○
Range shifts:
•
Q10 = rate of change of a biological system with
change in temperature
○
The higher the Q10, the greater the effect of
warmer climate on physiology
○
The current lack of a comprehensive
analysis of the capacity for physiological
plasticity across taxonomic groups and
geographic regions, constrains predictions
of the impacts of climate change
!
Acclimation decreases Q10
!
Q10 (thermal sensitivity) is highest
in acute
□
More protected from
dire changes in
temperature
◊
Closer to equator --> less
effect on Q10
!
Post-acclimation Q10 increased with
latitude (higher in marine?)
□
Increase in physiological rates with
increased temperature was less when
animals had opportunity to
acclimate
□
With opportunity to acclimate,
physiological rates of animals from
low latitudes were less affected
□
Results:
!
Physiological plasticity increases resilience of
ectotherms to climate change
○
Physiological plasticity:
•
Liver's ability to metabolize toxins
decreases with increasing temperature
!
Ex. Ambient temperature influences tolerance to
plant secondary compounds in a mammalian
herbivore (desert woodrat)
○
Physiological constraints:
•
Aggressive and bold behavioural
style
□
Rigid and routine-like behavioural
flexibility
□
Low stress responses (GCs)
□
Less sensitive to changes in
immediate environment
□
Less able to cope with
environmental change
□
More fit in constant/predictable
environment
□
--> "proactive"
!
Cautious/shy behavioural style
□
Flexible behaviour
□
High stress responses (GCs)
□
More sensitive to changes in
immediate environment
□
More able to cope with
environmental change
□
More fit in changing/unpredictable
environment
□
--> "reactive"
!
Stimulus --> perception --> personality
○
Success of individuals may be variable -->
differential fitness based on environment
○
Behavioural plasticity:
•
Unexpected cold weather during calving =
increased glucocorticoids
!
Increased glucocorticoids = disrupted
microbiome, susceptibility to infection
!
Pasteurella (typically harmless gut
microbe in small quantities) is a likely
culprit
!
70% of world's Saiga antelopes were dead within
2 weeks in spring of 2015
○
Stress physiology:
•
Responses to Climate Change
Explains fitness variation in a population by the
timing of breeding of the focal species and the
timing of species at the immediate lower level
○
Can occur at multiple trophic levels
!
Some species have greater plasticity in
response to abiotic cues
!
As temperature warms, phenology of
temperature-dependent processes advances
!
Study completed involved tits
○
Match/Mismatch Hypothesis:
•
Caterpillar abundance is matched to chick
rearing (due to sunlight)
○
Increased temperatures advance caterpillar
emergence (due to increased temperature) -->
mismatch abundance with rearing
○
Ex. In song bird species
•
Widespread implications for migratory animals
due to mismatch between cues on wintering
grounds vs. environment on breeding grounds
○
Temperature predicted to increase more rapidly near
the poles (~3.5 degrees in boreal forest region by late
century)
•
Naval base wallabies (need light) are mating
later in the season compared to bush
wallabies --> decrease in fitness
○
Ex. Artificial light at night desynchronizes strictly
seasonal reproduction in a wild mammal
•
Phenological Mismatch:
Age of sea ice (not as cold) has also decreased
○
Behavioural plasticity: shifting food
sources, storing food
!
Physiological plasticity: "walking torpor"
!
--> collapse of seal populations
!
*directly related to polar bear success
○
Average monthly arctic sea ice extent has dramatically
decreased since 1978
•
Prey upon and outcompete Arctic fox for
lemmings
○
Warming winters allow red fox to expand northward
•
Coat change species are typically found in
the north
!
Colour changes from white to brown in
circumpolar species
○
Clock genes turned to day-length program
seasonal moult
○
Due to shorter winter, have white coat
when snow has already melted (shorter
snow cover period) --> colour mismatch
!
Natural selection over time to adapt for
phenological mismatch
○
Rub selves into dirt to cover white
coat after snow has melted
□
Adapt to environment without time
for natural selection to occur
□
Ex. In rock ptarmigan
!
More immediate adaptation: behavioural
plasticity
○
Colour mismatch:
•
Climate Change in the Arctic:
Climate Change on
Vertebrate Biology
Wednesday,+ November+ 29,+2017 12:35+PM
Document Summary
Evidence: global sea ice area has drastically decreased (2017 was lowest year) -> habitat loss (rising sea levels, decreasing lake levels, melting ice, fire) -> disease thriving in warm or wet environments (ex. If current warming trends continue, estimated overall extinction risk in 1/6 animal species by end of the century. Intrinsic extinction risk is predicted from fossil record (23 million years) of marine genera and combined with rates of anthropogenic threat (+ climate velocity) Tropics are especially vulnerable (consider bias in diversity) Biodiversity bias: more species --> greater chance of these species to go extinct. Erosion of lizard diversity by climate change and altered thermal niches. Marbled salamander is increasing distribution and range in response to warming winter temperatures. Local populations of spiny lizards are going extinct in response to competition due to range shifts. Historical analysis of 48 species at 200 sites in. Since 1975, 12% of local populations are extinct, 4% worldwide.
