Lecture 12 - Climate effects on organisms, phenology and interactions

ecological niche modelling

assumes that a species is now found in places where conditions are suitable measuring ecological conditions there to produce an envelope of suitability

• best way to predict range shifts

how does niche modeling predict how conditions will change?

by using GCM (general circulation model) in order to map out where conditions will be suitable in the future

envelope of suitability

includes temperature, precipitation, diurnal temperature shift, etc

american Pika

adapted for life in high, cold mountains

• lethal when temperature is 27 C

species loss form sky islands model assumptions

• climate warms 3C

• habitat moves upward 500m

• habitat area shrinks accordingly cause mountains have a peak

• species lost according to habitat loss

S = cA*z

tells us how many species we’re gonna find in a given area as a constant and the amount of area raised to an exponent

what happens when A*z goes down?

we should expect a loss of species

what did the 2003 species lost in pikas find?

they resampled 25 mountain ranges and found that pikas extirpated in 7 of the 25 indicating that the extirpated locations had some component of human disturbance related to it

why is human disturbance considered a factor of pika species extirpation?

because the mountain ranges where pikas are still present match in temperature and precipitation to the unoccupied sites

how can pikas continue to persist in hotter environmental conditions?

through behavioural modifications like foraging, activity rates, etc

pronghorn antelope

migratory species that has a summer and winter range that migrate through natural gas fields

pronghorn antelope limitation

hard for them to move up slope and to deal with human disturbances like oil, natural gas exploration and barbwire fences

what are pronghorns good at?

they can move to whatever habitat they need to be at cause they are really fast migrational species

why are pronghorns good at migration?

because their skeleton convergence is similar to the african cheetah but mtDNA indicates closer relation to american cougar

Bramble Cay Melomys

small rodent found on a tiny isolated island near australia and papua new guinea, only endemic species of the great barrier reef

• herbivore reliant on herbaceous cover for food + shelter

why were Bramble Cay melomys extirpated?

due to ocean inundation causing dramatic habitat loss which they were dependent on for food and cover

seawater inundation

killed vegetation and destroyed habitat, vegetation and food sources, this caused extreme weather and waves that was destructive to the low level island of Bramble Cay

Bramble Cay melomys fate

population declined rapidly due to human caused climate change even though they were located far away from humans

response options

• change migratory locations and feeding ranges if there is no human disturbance

• phenology/change their timing

• change altitudinal location

• extinction

how do we make tracking genetic changes easier?

by focusing on genetic polymorphisms or Mendelian traits because we can make a direct inference of genotype from phenotype

lady bird beetle mendelian trait example

dark vs light shell

• thermal advantage under cold temperatures, low wind, intermittent sunshine and high radiation

Netherlands study

closer to the coast it used to be warmer and more moderate in temperature due to ocean buffering effects and as you got the the interior of the country it got much colder

dark vs light shell study

used to be even advantage between both shell types but now almost all of the time the orange/red shell was more advantageous because of the climate warming

climate response in ladybird beatles

short life cycle producing lots of offspring (short range species with high fecundity)

• same for seeds and fruitflies

change in fitness of genotypes in response to evolution

CO2 leads to warming which eliminates the temperature gradient and that change eliminates the fitness advantage of the dark shell beetles

antagonistic pleiotropy

natural selection favors alleles with short-term gains even if there are long-term costs resulting in bodies that are programmed to senescence and die

antagonistic pleiotropy political analogy

human political processes favour policies with short term gains even if there are long term costs