ESS 120 1st Edition Lecture 8Outline of Last Lecture I. Soil ErosionA. Land Degradation and LossII. On Site Effectsa. Soil ProductivityIII. Off Site Effectsa. SedimentsIV. Soil Loss Tolerancea. T-ValueV. Erosion Processa. AcceleratedVI. Types of Erosiona. Waterb. Windc. Gravitational Erosiond. Splash Erosione. Surface Erosionf. Channel ErosionVII. Soil CharacteristicsThese 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.VIII. Slope CharacteristicsIX. How to Stop ErosionX. Predicting Soil Erosiona. RUSLEOutline of Current Lecture I. Easter IslandII. Rock AgricultureIII. SocietyA. ChiefsB. ClansIV. Vanished ResourcesA. ConsequencesB. DeforestationCurrent LectureEaster IslandBelongs to Chile, gentle topography, mild climate, fertile soils, volcanic rock, limited fresh water, poor fishing, no coral reefs.- Discovered Jacob Roggoveenapril 5, 1722- Sev thousand people, malnourished, poverty and barrenness- Islanders subsisted on sweet potatoes, yams, bananas- After discovery many islanders were killed off by smallpox and kidnapping- Settled by either Pacific Islanders or possibly south americansLegend says chief hotumatu’s arrived in canoes with wife, 6 sons and extended family- After settlement, isolate from Polynesia- First 500 yrs lived close to beach, took advantage of sealife- First evidence of rock agriculture, must of interior converted to rock gardens, but no one lived thereRock Agriculture- Used stone to line composting pits to grow crops- Stone chicken houses (hare moa)- Stacked stones used to protect seedlings and plants from wind- Added rocks to soils as a mulch to improve moisture, moderate temperatures, reduce erosion, release fertilizers- Used rocks to dam intermittent streams to divert water or cropsBarry Rolett: “people would only use this method/this much effort if they were really struggling”Society- Chiefs and commoners- Chiefs lived in hare paenga (huge houses w/ salt floor)- Commoners located further inland, small thatch houses with chicken houses, oven, stone garden circle, garbage pit.Land tenure and clansDivided in 12 territories each belonging to 1 clan- Territory started at coast and extended inland, had one chief, ceremonial statues, different valuable resources- All territories united in religion and under one supreme chief.State ConstructionRequired lots of food for workers, rope and trees for sleds, canoe ladders and leversVanished Resources:21 species of trees such as Chilean palm burned for firewood, cut down for gardens, cremation, canoes, rates ate seeds- deforestation peaked around 1400 ad- dolphin, tuna, seal, sea turtles- 25 nesting seabird species, albatross- land birds, large lizards, disappeared from overhunting deforestation, predation by rats- crop yields decreased, soil erosion, dessication, leaching of nutrients.Consequences:Starvation, population crash, cannibalism maybeNumber of house sites declines 70%Chiefs and priests overthrownCivil war, spear points litter the islandStopped making statues, destroyed/toppled rivals’ statuesMoved to coastal zone, some to caves.Objections to self-inclined environmental destruction:• unrecorded European visitors before 1722• natural climate changes such El Nino****** what affects deforestation on Pacific Islandsdry islandcold high latitude islandsold volcanic islandsislands without aerial ash falloutislands far from central Asia’s dust plumeislands without makatea, coral reef thrust into airlow islandsremote islandsmall