GEOG 5 Gillespie Thomas 2012 Fall Week 4 Lecture 9 October 25 2012 Announcements Reading chapter 13 Midterm Tuesday after Halloween Nov 6th Handout of biodiversity hotspots Outline of Last Lecture I Discussion of temperate forests in the US II National Forests III Their conservation and their use Outline of Today s Lecture 1 Discussion of Tropical Forest and their use Today s Lecture Tropical Forests Mangroves Trees that grow in salt water Caribbean Swamps Trees that grow in Freshwater Amazon Tropical Rainforest Very little nutrients in soil Huge levels of diversity Tall trees with no very little branches as sun shines directly on top Very dark in the understory Cloud Forests Trees on the angle of a mountain 100 humidity Trees gradually get shorter and shorter as climb up the mountain Dry Forest Trees on the dry side of mountains Very rich soil These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Why Tropical Forest is disappearing 1 Subsistence agriculture grow food just to feed themselves Historically done by slash and burn chop down trees in dry season and then burn them to make the soil more fertile nutrients in the top layer of soil for 3 5 years Agricultural Frontier Transmigration Projects actively take people from the city into a rural area in exchange for land and a house Brazil and Indonesia 2 Commercial Agriculture Plantations Oil palm rubber SE Asia Bornea Coffee bananas cattle ranching Central and South America 3 Forest Fires In the tropics fire is not a natural occurrence Build roads create fires El Nino Amazon becomes dryer and fires occur 4 Fuel Wood used for cooking Buy or collect Living Fence in the tropics people will plant trees around their lot of land 5 Timber any wood that s cut down and sold for economic gain Woods from the tropics are in great demand Mahogany can t be grown in monoculture due to an insect which will kill the trees Central and South America Teak can be grown in monoculture ITTO an organization which ensures the trees are cut down sustainably Indonesia in the 80s half of the trees were cut down Problems that occur due to deforestation Fragmented Significant impact on flora and fauna o Species loss Species area relationship greater the area greater the number of species Therefore as we cut down trees we loose species o Selection extinction certain species go extinct before others I Large scale e g jaguars harpy eagles II Carnivores III Solid forests species that have evolved to the dark and wet understory IV Rare species low density so when area disappears they do to Non native Invasions o Mainland all niches are filled by species and lots of competition o Island open niches and no competition means that they are vulnerable to invasions Introduction of non native species into areas with open niches Hawaii Guava pigs and non native birds love it and disperse it This means native plants are destroyed Rats eat all the birds eggs Pigs eat non native plants and spread them across the island Mongoose the mongoose is a big predator and kills lots of other animals Australia Cactus spread across Australia no native plants to stop it Bunny rabbit huge explosion cause they breed so quickly and eat everything Cane toad explosion and they are poisonous MEMORIZE FOR MIDTERM on handout Biodiversity hotspot concept 2000 Regions around the world with incredibly high diversity high endemism restricted to one area under exceptional degree of threat due to humans If you save 2 3 of Earth s service you can save half of all plant species 42 of all vertebrates These places are prioritized 1 Indonesia o World s largest Islamic country o Incredibly diverse culture Polynesians Malaysians Hindi Bali o Hotspot 1 Sudaland Sumatra Bali Java Borneo Threats deforestation agriculture oil palm o Hotpot 2 Wallacea 2 World s Most Endangered Forest youtube it 25 mins