Tuesday, September 10, 2013

Week 3 - 10 Sept. 2013 Geography and topography affects forests


We reviewed the 6 forest biomes and discussed the best one to live in.

Topographyshape and features of the earth, including elevation (relief)

Altitude = elevation as measured from sea level which is at 0 meters in elevation.
·         Temperature decreases as altitude increases.
·         Altitude affects the distribution of precipitation. 
·         Plant and animal species vary by altitude.

Sea level = 0 m
Pic Macaya = 2,347 m

RAIN SHADOW = a dry area on the LEEWARD sides of mountain ranges.  It is created due to an air mass rising up the windward side of a mountain.  As air rises and cools, water condenses and comes out as precipitation.  When this air mass passes over the mountain it descends but has no moisture. (and sometimes it also causes L'effet de foehn).

Windward – The side facing into the wind - directly receives the wind.  The upwind side.
Leeward – The side facing away from the wind.  The downwind side.

The mountain ranges on Hispaniola create a rain shadow over Haiti.  The DR receives more rain than Haiti.  The western valleys, along the Haitian border, remain relatively dry, with less than 760 mm (29.9 in) of annual precipitation, due to the rain shadow effect caused by the central and northern mountain ranges.

Altitude mimics latitude in temperature!

As an ecologist you need to understand these weather patterns because you will find different plants and animals at the top of a mountain than at sea level. 

Latitude and Longitude
Latitude lines are imaginary horizontal lines on the earth, like the equator.
Tropic of Cancer = 23.5˚ North and the Tropic of Capricorn = 23.5˚ South

Longitude lines are imaginary vertical lines on the earth, like the prime meridian.

(Neotropical Companion Ch 4 pg 86; Tropical Ecology Ch 4 pg 120)
Latitudinal diversity gradient – increasing biodiversity with decreasing latitude.
The tundra, at high latitude (80-90˚N), has fewer species than the tropical rain forest, near the equator (0˚)

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