Download Ecology Desert, Tundra, and Grassland Teacher notes 2015

Ecology Grassland, Desert, and Tundra Biomes Notes
Voc. List: cultivated, sod-former grasses, bunch-grasses, humus, runners, tufts, vertical feeding patterns,
leaching, limiting factor, pavement, succulents, granivores, nocturnal, estivating, desertification,
fellfields, and migration
Grassland Biomes
Characteristics of grasslands:
 Rainfall is usually 25-75 cm/year
 High evaporation rate
 Usually cultivated (used as farm land) or used for grazing
 Usually native species have been replaced by invasive non-native species.
 Not forested-due to moisture &/or fires
o Fires are common due to lightning
o Fires are important in the development of grasslands because it keeps the number of trees and shrubs
low
 This allows grasses to grow and spread because most of the grass plant’s mass is underground
 Example: One rye plant may grow only 2 mm but have up to 600 km of roots beneath
the soil. Therefore when a fire strikes the grasses are relatively unharmed.
 Also, fires are a benefit because it burns a layer of dead grass away converting it to
valuable nutrients-act like a fertilizer.
 Animals graze or burrow
o All grasslands have large grazing animals such as antelope and bison
o Grasshoppers and other insects feed on the seeds and leaves of grasses, as do small herbivores like mice,
gophers, and prairie dogs that burrow in the ground
o In the North American prairies, the top consumers are coyotes, foxes, snakes, and birds of prey
 Grasses are either sod-formers (like a carpet) or bunch-grasses (forms clumps)
Grasslands can be divided up into two different biomes: Savanna and Temperate Grasslands
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Savannas (tropical grasslands)-are tropical or subtropical grasslands ranging from dry scrubland to wet, open
woodland
a. Found in parts of India, Africa, and South America between tropical rainforest and desert biomes
b. Have 3 months of rainy seasons (wet season-starts in May) and up to 9 months of drought (dry season)
 Can have up to 150 cm of rain per year during the short rainy season
c. Vegetation contains lots of grass with some shrubs or trees, often widely spread.
 Grasses, shrubs, and trees must be resistant to drought, fires, and grazing animals to survive.
 In the dry season the plants lose their leaves and die back
 The plant have large horizontal root systems to obtain water even far away
 Runners are long horizontal stems above the ground. Runners are used by some plants
to reproduce quickly
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 The coarse grasses have vertical leaves to conserve water and allow less of the plant to be
exposed to the hot sun.
 Grasses grow in tufts-large clumps of tall, coarse grasses.
 Animals have vertical feeding patterns-animals eat vegetation at different heights
allowing for different eating habits.
 The trees and shrubs have thorns or sharp leaves that keep them from being eaten by
grazing animals, such as gazelles. They also grow and recover quickly when damaged.
Grazing Animal Examples: gazelles, elephants, zebras, giraffes, and black rhino
 Grazing animals are herbivores
 Most migrate to search for food and water holes
 Some predators follow grazing animal paths
Most savanna animals only give birth during the wet season
Other organisms:
 Termites are small but build the largest homes that can be seen across the whole savanna
Dung beetles build round next from the droppings of other animals and then lay their eggs
in them
 Ostriches are 7 foot tall birds with great eye sight and run fast when a predator is after it. They
also lay huge eggs that are big enough for several people to enjoy.
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Temperate grasslands:
a. Moderate rainfall to support mainly grasses
b. Cover large areas of the interior of most continents
c. Trees and shrubs can’t be established because of frequent fires and not enough rainfall.
d. Soil is fertile and very productive
 Decomposition slows down during the winter months
Four main types: Prairie, Steppe, Veldt, and Pampas
 Prairies-are grasslands characterized by rolling hills, plains, and sod-former grasses.
 Found in the United States-Great Plains (North America’s Breadbasket of the world)-1.4
million square miles
 As you move from the east to west the rainfall decreases
 Most rain near mountainous areas up north
 Soil in prairies can hold water very well because soil organisms create air spaces that
hold the water.
 Humus helps hold moisture too-layer of organic material formed as plants and animals
decompose.
 Lots of flowering plants and herbs
 Most of the grasses have roots that form a mat in the soil-Sod-former grasses
 Big bluestem grass have roots 7 ft. long
 Switchgrass have roots 11 ft. long
 Animals: buffalo, elk, deer, rabbits, and prairie dogs
 Prairie dogs dig huge underground tunnel systems
 Problems:
 Lots of farming
 Lots of endangered species
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 Steppes –are dry and cold grasslands
 Found in every continent except Antarctica and Australia often near desert areas-mainly
in the USA, Mongolia, Siberia, Tibet and China
 Most people won’t live in these areas because of the extremely hot and dry
summers and very cold winters
i. Common wildfires in the summertime
 Bunchgrasses are short, fine bladed grasses that form in clumps
 The more rain the taller the grass
 Some animals hibernate in the colder areas to save energy
 Rainfall: 10-30 inches of rain /year
 Problems:
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Lots of endangered animals
 Human farming and digging for oil
 Veldt/Veld
 Found in South Africa beside the savanna and have similar organisms
 The 1st humans lived in these areas
 Usually the animals travel in large herds
 Zebras, gazelles, and wildebeests often travel together for more protections
from predators like lions
 Have more trees and shrubs than the savanna
 A thirsty elephant will tear a baobab tree apart to eat the spongy, moist inner
wood
 Dominate grass are the red grasses
 Rainfall: 15-35 inches of rain/year
 Temperature average:
 Summer 65-80oF
 Winter 45-60oF
 Problems:
 Lots of farming
 Ostrich extinct in these areas (Competitive exclusion)
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Pampas
 Found in South America (mainly Argentina-south of Buenos Aires to Uruguay)-300,000
square miles-South America’s Breadbasket of the world)
 Flat ground that is warm and humid
 Fertile plains with mainly grasses similar to the prairies of North America
 Other plants include cattails, water lilies, and reeds
 They have adapted to these areas
 A lot of organisms burrow in the ground including owls
 Bird examples: Have different types of finches (birds) and Greater Rhea (cousin to the
Emu)
 Dry season is the summer
 Temperature average: 18oC
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Chaparral
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Temperate woodland that receives enough rain or mist from the ocean/sea to support trees and shrubs found
worldwide.
o Found in Middle latitudes about 30o North and South of the equator
o The areas have moderately dry, coastal climates with very little or no rain during the summer
o Land can be flat plains, rocky hills, and mountain slopes-often seen in Old Western movies
Plants: Bay laurel, herbs, olive trees, scrub oak, blue oak, coyote brush, common sagebrush, flowers such as Fairy
Duster (pink), French Broom (yellow), and King Sugar Bush (pink flower that is about one foot across with paddlelike leaves
o Leaves are small and leathery to help retain water
o Leaves contain oils to promote burning of other plants that compete with chaparral plants-chaparral
plants adapt well to fires and can resprout new roots quickly
Animals: Quails, alligator lizards, chipmunks, mule deer, coyotes, jack rabbits, horned toads, praying mantis,
honey bees, and ladybugs
o Animals often use camouflage
Average Temperatures: 10oC in the winter and 40oC in the dry summer
o Fires are common in the summer months
Problem: Threatened by human development
Deserts
Irrigation of desert soils has enabled some nations to turn deserts into croplands. In the Middle East, for example, irrigation
projects have turned the Golan Heights into citrus orchards. Such projects require careful planning and management to
avoid draining water resources and accumulating salts in the soil.
Common properties of a desert
 The evaporation rate is high and exceeds rainfall-so very little rainfall
o Rarely 25 cm of precipitation/ year
 Some areas 0-1 inch/ year
o Lack of rainfall is a limiting factor (an abiotic or biotic factor that restricts organisms in some way) for
desert biomes
 Hot by the day and cool by night
Formation of the Desert
 Deserts cover roughly 30% of the Earth’s surface and are found on every continent except Antarctica
 Most Hot deserts are found between 23.5oN (Tropic of Cancer) or S (Tropic of Capricorn)
 The location of the desert varies slightly from day to day because wind carries the sand and the land formations
trap the sand
 Erosion in the desert: Water and Wind
o Desert soils tend to be rich in minerals but poor in organic material because of erosion
 Rainwater moving through soil carries minerals deeper into the soil by a process known as leaching
(water causes minerals to go out of the rocks, soil, and possibly organism and go elsewhere)
 Very little rain forms in deserts so very little leaching occurs in the soil. As a result, the
upper layers of the desert soil become rich in minerals
 Wind erosion occurs where loose dry desert soil and expose a lower layer of soil called pavement-the
desert floor (made of hard-baked sand, bare rock particles, or both)
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Problem/Limiting Factor:
 People also cause deserts to form by desertification
o In this case, people over-farm and allow animals to graze too much losing the nutrients, grass/crops.
 Lack of water
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Four Types of Deserts
Hot and Dry Deserts
Plants: Woody-stemmed and soft brittle-stemmed shrub plants and a wide variety of other plants including cactus
o Cactus have spines that are actually considered leaves
 The spines reduce the loss of water by reducing the surface area from which water can evaporate
 The spines also protect cacti from being eaten
 Cactus also store liquid in their tissues
 Plants such as cacti, are called succulents because they have thick, water-filled tissues
 The stored water allows plants in dry areas to survive
Animals:
o Primary producers depend upon the availability of water
o Granivores are important herbivores of the desert ecosystem-for seed dispersal
 Birds, insects, beetles, and burrowing mammals
 Ex. Ants gather seeds underground
o Most desert animals adapt to the heat
 Estivating-burying themselves in the ground and sleeping through the dry season
 Elf owls nest in cactuses to avoid predators
 Insects and spiders are covered in body armor to protect themselves and help them retain water
 Reptiles like Gila monster and rattlesnakes, have a thick, scaly skin to prevent water loss
 Rodents like kangaroo rats store their water in the form of urine
 Most rodents and reptiles burrow in the ground during the daylight and seek food at
night-nocturnal
Average Temperature:
o 20-25° C
 can get cool at night
 daytime temperatures can reach 49oC in extreme conditions
 lowest winter temperatures can be -18oC
Precipitation:
o Zero to 1 inch of rainfall/year
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Semiarid Deserts –Most common with similar plants and animals as Hot and Dry Deserts
 Average Rainfall: 2-4 cm
 Temperatures range from 10oC to 38oC
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Coastal Deserts-Found in coastal areas
Plants: black sage, small flowers, and different species of brush and bush
Animals: Several have specialized adaptations
o Amphibians have an accelerated life cycle to improve their odds of maturity before the dry season
 Some mature toads seal themselves in burrows with gelatinous secretions for 8-9 months or
when heavy rains occur
o Some insects and shrimp lay eggs that stay dormant until heavy rains
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o Coyotes, badgers, eagles, owls, lizards, and snakes
Average Rainfall: 8-13 cm/year
Average Temperature:
o -2 to 14°C winter
o 21-25°C summer
Cool Deserts
These areas can have extremely cold winters
o Antarctic and Greenland
Animals:
o Jack rabbits, kangaroo rats, mice, squirrels, lizards, badgers, and coyotes
o Most small rodents burrow underground
Plants:
o Sagebrush is the dominate groundcover
o Most deciduous plants have spiny leaves
Precipitation: Rain or Snow (in the winter): 9-46 cm/year
Average Temperature:
o Summer: 21-26oC
o Winter: 2-14oC
Tundra
General Characteristics of Tundra Biomes
 Cold and desert-like
 Some areas have glaciers
 Fellfields-Rock desert
 Frost molds the tundra landscape
 Permafrost: permanent frozen layer of soil
o All vegetation have to grow close to the ground surface
 Water can’t drain away, so flatlands of the Arctic are wet and covered with shallow lakes and bogs
 Fine soil material and clay
 Problems:
o Nutrients are low due to short growing season: Nitrogen is unavailable for N cycle
Tundra Animals
Many of the animals in the Tundra migrate.
 Migration-Large groups of animals that travel together for water and food.
o Ex. Caribou (close relative of the reindeer) is a large migratory mammal
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Two Types of Tundra
I. Arctic Tundra- Grassland and mixed shrub-land in the Arctic
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Location: Latitudes 55° to 70° North (Arctic Pole)
o Some areas receive 24 hours of Sunlight in the summer and 24 hours of darkness in the winter
Permafrost is 10 inches to 3 feet deep
Growing season only 60 days so plants such as moss, shrubs, grasses, and small colorful wildflowers are possible
Plants:
o Two most common plants are bearberries and willows
 Bearberries are only found in Tundra biomes and the berries are often eaten by birds
 Willows are often eaten by humans because they are rich in Vitamin A, C, and Calcium and used
by humans to start fires
o Trees get rough 1 meter tall and appear more like a scrub than a tree
 The short growing season, limited space for roots to grow, and strong winds cause dwarfed trees
Animals: reindeer, caribou, lemmings, voles, arctic hares and foxes, wolves, squirrels, lots of bird, black bears,
grizzly bears, and polar bears
Insects: mosquitoes, flies, moths, grasshoppers, and arctic bumble bees
Fish: salmon, halibut, and trout
Temperature range: -70oF in the winter to 80oF in the summer
Average Precipitation: rain or snow (mainly) 6-10 inches
Problems:
o Global warming –melting of permafrost
o Short growing season
o Extreme cold
o Lack of water
Alaskan Pipeline:
 Took several years of planning, construction began on the Alaska oil pipeline, which transports oil 1285 km south
from the North Slope of Alaska.
o The pipeline was completed three years later.
o The first oil left Prudhoe Bay (North Slope) on June 20, 1977
 Because oil must be kept warm in order to flow, parts of the pipeline were constructed above the ground to
protect the permafrost from melting.
 To avoid interfering with migration of caribou and other animals, the pipeline includes 400 raised sections for
animal crossings.
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Alpine Tundra-Mountainous areas at high latitudes where trees can’t grow
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Able to withstand wind due to low and ground-hugging vegetation
Growing season is 180 days
Animals and plants are about the same as Arctic Tundra
Evening temperatures are usually below freezing
Precipitation same as Arctic Tundra
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