GEOG 5Gillespie, Thomas2012 FallWeek 4Lecture 9October 25, 2012Announcements- 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 LectureTropical 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 understoryCloud Forests - Trees on the angle of a mountain - 100% humidity - Trees gradually get shorter and shorter as climb up the mountainDry Forest - Trees on the dry side of mountains - Very rich soilThese 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 othersI. Large scale e.g. jaguars, harpy eaglesII. CarnivoresIII. Solid forests – species that have evolved to the dark and wet understoryIV. 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 invasionsIntroduction 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: Wallacea2. World’s Most Endangered Forest: youtube it – 25