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Lecture

Lecture 23 .docx

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Department
Biology
Course
BIO220H1
Professor
John Stinchcombe
Semester
Winter

Description
Lecture 23: Climate effects on organisms, phenology, and interactions  Basic EEB principles (and example of PETM) leads us to expect: o Migrations:  Latitudinal (toward poles)  Altitudinal (toward mountaintops) o Evolutionary change o Population dynamics, incl. extinctions o Phonological change Ranges of tolerance and ecological niche modeling:  Find out where a species is now,  Measure conditions in its current age (i.e. average temperature, rainfall, vapour pressure, altitude, distance from the ocean)  the abiotic environment o Gives us a statistical condition that gives the abiotic conditions that are suitable  Take the global change models and see how they’ll change in the future  Then in the future, find the same spots in the map that are currently suitable  By comparing where it is now, we can see how far the range has to shift  Where the climate is and where that climate will be found Such shifts have happened routinely through geological time:  All the trees, plants, animals have colonized this region relatively recently (they dispersed)  These natural changes are slow enough for things to re-colonize and keep up with the pace of change  Imagine glaciers retreating from southern Ontario and there’s this front that’s following it. It’s a gradual process and the species are tracking this. The downside is that it’s happening so fast that the species can’t keep up o ** listen to recording again  It’s an evolutionary response and species are evolving as climate changes  We need to keep track of whether they’re just following their current conditions northward, or are they going to evolve the ability to tolerate a warmer, dryer habitat in the same location where they are  Discerning out of these two outcomes is crucial  Pronghorn ‘antelope’: migratory grazers of open grassland  They migrate between summer and winter ranges through the orange bit (map)  The downside is that this particular area (circled in white), is it’s really rich in natural gas.  What pronghorn are good at? Fastest north American mammal by far  Why they are so good at it? o They evolved to run away from cheetahs o Skeleton is similar to cheetahs that we see in Africa today o But more closely related to American cougar  Not very good at getting through barb wired fences D:  Whole herds are killed by fences  There will be antroprogenetic change  can’t get tot their habitat (can’t move)  See it in many other species Ex. 2: Passenger pigeons  Pigeon flocks were 4-5 miles, so thick that they blotted out the sun  These flocks were really huge and big flocks  A shattering decline: from the most abundant to absolutely nothing:  At European settlement, 3-5 billion individuals  ~1/3 of all NA bird individuals  Migrating flocks 1 mile wide, 300 miles long  In 1870s remaining flocks still ‘darkening the skies’  Extinct in the wild by 1900  1 September 1914, ‘Martha’ dies at 29 in the Cincinnati Zoo  One of the most spectacular migrations you can imagine  The span of them are 150 years, limiting of ecosystems. Why?  What happened?  So there were shooting parties, organized hunts: organized slaughter  And these are HUGE birds, not the irritating pigeons you see on St. George :p  Slaughter because thought they were inexhaustible  But with organized slaughter and shooting, human modification of the landscape was changing what the passenger position was adapted to o Refer to figure in notes  Hunting could not have done it alone: o Nut feeder pigeon was so successful because it beat the predator- avoidance strategy of oak and beech mast crops o Colonial life-style; allele effects likely o In pre-settlement NA there was always mast somewhere… o … but not after massive loss of forest and fragmentation o Remaining flocks searching for shrinking remnants of forest; hunters recruited by telegraph and railroad; no predator refuge, no density- dependent controls on hunters o The irony: today’s landscape would probably prevent extinction in New England o In disrupting migrations and habitats will have an effect Ex. 3: Pikas in the Great Basin  Many small mountain ranges surrounded by desert  Adapted for life in high, cold mountains (isolated)  Lethal temperature ~27C  When the temperature gets too wrong, the pikas are toast  They need cold temperatures on top of mountains  The downside is that as you go up the mountain, the mountain area around you will warm up. Eventually you get to the summit and you can’t get any higher  Modeling species loss from sky islands with climate change (1996)  Mammals on mountain ranges in Great Basin  Model assumptions: climate warms 3C  Habitat moves upward 500 m: habitat area shrinks accordingly  Species lost according to habitat loss  From shrinking habitat, we want to predict what species are going to be left after we shrink remaining habitat  S=cAz (fundamental equation)  the relationship between area and the number of species that can be supported  Each dot is the example of a mountain (refer to graphs )  Predict as you move up 500 m, you see how many m^2 habitat when you get up the mountain range  Using montane mammals to model extinctions due to global change: o Pikas  they’re predicting extinction Measuring species loss from sky islands (2003)  Resampled 25 mountain ranges where pikas had been found earlier (and they were suitable habitats)  Pikas extirpated in 7 of 25 Ex. 4: Pollinators (bumble bees)  Habitat  mean snowfall (since 1975)= 11.1 m  Range = 4.7-16.4m  In the 1970s, Graham Pyke’s altitudinal transects (down at the road and going up and observing bumble bees)  Bumble bees are key pollinators in this ecosystem and they’re a necessary element of reproduction of a whole host of montane wild species  Graph: o In 2007, both altitudinal transects have shifted to the right (to find same composition, have to go up the mountain) o See upward shifts  How important is a shift of 250 m? Recall altitude-latitude conversion from BIO120 o Roughly, 100 m altitude= 300 km latitude o SO ~ 250m shift equivalent to ~800 km shift o This is the only consistent driver of otemperature in this region that’s going to produce this directional shift over this length of time  Are these changes general? o 1960, average temperature of baseline (climate is warming) o Graph B, there are we
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