Geog 112: Week 10

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  1. Island biogeography
    • • A way of explaining and predicting the affects of distance from mainlands and islands to how much bio diversity is possible or occur on an island
    • • Island size, Island distance, From a population source will affect the diversity of the species you are going to find on that island
    • • The closer an island is to a mainland or another island, the closer they are to a source
    • • Closer to a source or a species
    • • So that means that the closer you are to something the more species there are going to be, the farther away you go the fewer the species you are going to have
    • • The farther away something is the less likely it is for any species to be able to travel there so of course that means there are going to be a fewer species on a further island
    • • Islands that are more isolated are less likely to receive immigrants
    • • If you are last island on archipelago chain you are going to find less species there
    • • However if you move that island far away from everything else there is really going to be fewer species
  2. The rate of extinction
    • • Once a species has finally colonized an island it really depends on the islands size
    • • Called AREA affect, or species area curve
    • • Area affect = means that a larger island has the ability to provide more habitats, therefore more opportunities for more varieties of animals to survive there
    • • Habitat Heterogeneity = the difference (increases the number ofspecies that will be successful after immigration) homogeneity =the same animals
    • -So overtime the forces of extinction and immigration result in a equilibrium
    • • So if you have a small island the chances of extinction increase almost exponentially because you could get a lot of species that was close to source of immigration (island near mainland) bunch of animals are going to fight themselves and not enough habitats,space, or resources
    • • So only a certain thing of carrying capacity can be reached on the island
    • • There is a magic point on island where the island is going to balance itself out
    • • if you have an island all alone just doing its thing
    • • Based on its size, distance, number of habitats
    • • The island itself will reach this point of equilibrium where it has exactly the appropriate number of species on the island and the resources on the island can accommodate.
  3. Influencing factors that hav subsets
    • • Degree of isolation
    • • Length of isolation
    • • Size of island (larger area facilitates greater diversity)
    • • Habitat suitability (climate (tropics arctic)
    • o Initial plant and animal composition
    • o If it was previously attached to a bigger landmass
    • o What was there before the separation occurred
    • o What is the current species composition (that is going to influence what is going to be on the island)
    • • Location relative to ocean currents
    • o Influences nutrient content
    • -What nutrients are going to be available for the fish on the island
    • -Ocean currents also affect seed dispersal
    • -Seed dispersal can happen in oceans
    • • Chance
    • o Impacts of chance arrivals
    • o There is a species of crane that has showed up in Florida because it got lost
    • o A bunch of storms and weather patterns and they all got lost and they all ended up stopping in Florida
    • o Actually happens with a weird amount of birdso
    • • Human activity
    • o Causes disturbances on islando They plow things up and cutting up forests
    • o Or just bringing up non native species on the island that out compete the native species
    • o ^can all cause problems
    • o ***Can develop dwarfism, or gigantism where it is to their advantage tobecome smaller or longer***
  4. The experiment
    • • Back in 1960’s there was series of mangrove islands in Florida
    • • They fumigated them and killed everything
    • • Kept the plants but it killed everything else
    • • Made sure everything was dead and they waited to see how long it took for the immigration of species to get to each one of these islands
    • • And this is how they came up with the theory
    • • Islands that were closer to mainland got more species quicker
    • • And theory worked out perfectly, animals acted exactly how they guessed
    • • This is how they figured it out they actually killed everything off
  5. Krakatau
    • • Example of a natural experiment (occasionally nature does this)
    • • In 1833 the volcano erupted and half of Krakatau was blown today and the remaining portion which they call rikata
    • • All three of islands became a sterile landscape
    • • In may of 1884 on the island of rikata the remain living island
    • • The only thing living on the island was 1 poor spider
    • • No flies, nothing for it to eat they didn’t know how it got there
    • • By 1886 scientists decided that they should really be looking at this because it is a brand new sterile landscape
    • • 1897 there was actually enough plants and seeds on the island to attract birds and bats and apparently spiders came back
    • • things that could fly or things that could hitch a ride
    • • 1908 they finally counted 13 species of birds (took a long time for island to recover)
    • o the first non flying species was monitor lizards that could swim
    • o In mid 20th century pigs showed up but no one knows how they got there
    • o Otters came and became first mammal species with pigs
    • o As of 1991 the only island non flying vertebrates were reptiles, amphibians, and rats (rats can go anywhere)
    • o A lot of vegetation on island so migratory birds come and again the lizards but no other vertebrates
    • • Since 1991 it is like a big drop off of of mammals and birds
    • • After eruption there were only about a dozen animals and half of those were bats
  6. Because of volcanic activity
    You can be an island one day and gone the next
  7. Target affect
    • o If an animal is on an small island and resource are running short
    • o And theres a natural tendency for survival
    • o So you want to find some area where there are going to be resources for you
    • o Its why animals will move from one location to the next
    • o It is in seraph of more resources
    • o If there are more resources on a larger island than that larger island is going to be the target
    • o Is goingto be where more animals are going to try to end up
    • o They will immigrate to a smaller island and die out
    • o But when they hit big island they are able to survive
  8. Single Large or Several Small (Sloss)
    • • We are creating artificial islands
    • • So if we are going to try to conserve wildlife (strictly about wildlife not plants)
    • • Then we need to give them a habitat in which they can live and survive
    • • The question became how do you determine what is right?
    • • So professor Diamond, in 1975, he came up with some rules about designing protected areas
    • • ^^which were based on theory of island biogeography by (carther and Wilson)
    • • one of his suggestions was that a single large reserve would be better than several smaller reserves
    • • Just better to have one area
    • • Many argues but now this theory of SLOSS is accepted
    • • Generally come out to concept that it depends upon the circumstances
    • • One big one that is in tact is going to be better than fragmented ones that aren’t connected together
    • • If you have to have a bunch of smaller ones than you can overlap them somehow it would be better
    • • As much as you can connect habitats together the better you are
    • • Also round is better because you have a less of a chance of hitting the edge
    • • Its rough on the edges
    • • The best habitat is in the center of the reserve
  9. Species especially vulnerable to fragmentation
    • • Wide ranging
    • • Poor dispersal abilities
    • • Specialized requirements
    • • Low fecundity
    • • Vulnerable to human exploitation or persecution
    • • If you cant move well or disperse well then fragmentation is going to be a huge problem for you
  10. Biological Dynamic Forest Fragments Project
    • • Worlds largest scale and longest running study on habitat fragmentation
    • • It is one of those examples of you couldn’t do it today
    • • Located in amazon rainforest and stared in 1989
    • • At a point when scientists and conservationists were just beginning to realize that habitat fragmentation might be a problem
  11. The Amazon Rainforest
    • • Is a charismatic landmass (it is as charismatic as they come)
    • • Unbelievable biodiversity in it
    • • Conservationists have to choose their battles wisely
    • • Amazon has for decades, way before the invention of biodiversity hotspot has been capturing peoples imaginations
    • • Because it gets so much popularity on its own, that’s why its not a biodiversity hotspot
    • • It is by nature, being a race horse in bio diversity
    • • Represents ALL forests and also inspires people to care about landscapes in general
    • • Makes people think about habitat fragmentation everywhere
  12. Rainforest cover by Bio geographical Realm
    • -almost a quarter of the worlds rainforest occur on islands which means that you have a double set of problems
    • -Global rainforest cover: essentially around the equator and is gettingsmaller by the minute
  13. Ultimate Question (Nicaraguan island) Ometepe island
    • what happens when you have an island habitat that becomes fragmented?
    • • You have essentially created an island on an island
    • • Whole island is 2 volcanoes that are attached in the middle
    • • Ometepe island is a perfect example of influencing factors
  14. Madagascar (remaining primary vegetation)
    • • Difference with Madagascar is that Madagascar’s continental safe shells broke off super continent about a million years ago (part of Africa)
    • • Madagascar essentially a living island of diverse species
    • • Despite Madagascar’s proximity to Africa, it does not share any of the same animal groups of Africa
    • • Instead all kind of really unique species have developed there overtime
    • • The number of habitats on Madagascar is very diverse
    • • It is a biodiversity hotspot
    • o Its got tropical rainforests, desert, every type of climate accept tundra and taiga
    • o Does have some high mountain ecosystem
    • o But doesn’t get high enough for snow
  15. Reliced species (species that are unchanged)
    • • About 90% of plant life on Madagascar is endemic
    • • Ground Rollers
    • • Cuckoo Roller
    • • ^^60% of birds on Madagascar are endemic
    • • so many of the species are also reliced species
    • o Elephant Bird
    • -Very big bird that can fly
    • -880 pounds and up to 10 feet tall.
    • -Has been extinct since the 17th century
    • -The eggs are a little over 3 feet in circumference
    • -For 18,000 dollars you can have your own elephant bird skeleton
  16. One endemic family on island which is a type of iguana
    • -90% of reptile species are endemic
    • -Primarily those species are geckos and chameleons
    • -Opluridae Family
    • -Chamelon
    • -Nile Crocodile = the only one that is not endemic
    • -Gecko
  17. Lemurs
    • • 5 families
    • • 15 genera
    • • 100 species
    • • come in huge variety of sizes
    • • Believed that they crossed Mozambique channel and was thought to be 400 miles wide, but its believed that it was much shallower and that the original lemurs were able to swim
    • • Also the currents changed and there was no going back
    • • All of these lemurs are on endangered species list
    • • They are eaten and hunted as pets
    • • Most of them are endangered species list
  18. Giant Lemur
    • • Was enormous and existed until relatively recently
    • • There are 17 extinct lemur species on Madagascar
    • • Lemurs are only found on Madagascar
    • • This one weighed 400 + pounds
    • • Diurnal , and filled a very special niche
    • • Disappeared because humans hunted them to death and off they went
  19. Why is rainforest so important to biodiversity?
    • • Every forest is important but the rainforest is particularly important because it has a little thing to it
    • • The thing about the rainforest is that it has all of these different levels to it
    • • All of these different vegetation levels, and creates a whole bunch of different niches
    • • All of these levels have been growing for hundreds of years
    • • And when you cut down the rainforest, it never grows back and it only has good soil because nutrients falls from the tall trees
    • • If you cut it down, and leave it alone, stuff will regrow, but what will NOT regrow is a rainforest, a FOREST will grow back not a rainforest
    • • A rainforest cannot regrow because it is all of those different layers
    • • It would take tens of thousands of years to recreate that rainfores
  20. Rainforest different levels
    • o Forest floor = almost no light
    • o Understory layer = partial light (whole different ecosystem)
    • o Canopy layer =
    • -all of the trees that cover, connect together (whole new ecosystem) (sloths, never have to come down
    • -A whole bunch of animals that never have to comedown
    • o Emergent layer = is where trees emerge out to the sun
    • -Different things that live up there as well
  21. More than half of all land animal species on each are found in the rainforest. Why?
    because of niches
  22. So where does everything else live?
    • -the ocean
    • • Oceans = largest variety of ALL animal species
    • • It is harder to study what’s in the ocean because it is so vast
    • • In 2009 the Smithsonian had a ocean research project and they were able to identity 210,000 different oceanic life forms
    • • But now they’ve realized that there’s twice as much as this
    • • They’ve got 20,000 fish species and another 20k or so in the mid water level (crustaceans, jelly fish, etc)
    • • The trickiest one is the ocean floor (at least 100k species down there)
    • • you cant bring sample up
    • • amazing variety of animals in the ocean
  23. Ocean Video
    • • So many nasty and big critters in ocean
    • • And even creepier looking ones in deep ocean
    • • Big ass spider crabs eating whale carcass
    • -The reason she showed us that video segment is because of some of the amazing adaptations you see in the ocean like camouflage
    • - how cooperative hunting works between dolphins, bird, and fish
    • -think of ocean life as the same way as land animals -they function the same
    • -lots of different species feeding off dead carcass
Card Set:
Geog 112: Week 10
2013-12-09 00:44:47

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