Climate and Terrestrial Biodiversity

Chapter 6

(Biomes: Sections 3-7)

Key Concept 1: How Does Climate Affect the Nature and Locations of Biomes?

Differences in average annual precipitation and temperature lead to the formation of tropical, temperate, and cold deserts, grasslands, and forests, and largely determine their locations.

Climate Affects Where Organisms Can Live

Major biomes• Similar climate, soil, plants, animals throughout

world• Ecotone

Latitude and elevation

Annual precipitation• Deserts, grasslands, forests

Temperature• Tropical, temperate, polar

The Earth’s Major Biomes

Generalized Effects of Elevation and Latitude on Climate and Biomes

Fig. 7-10, p. 147

ColdPolar

TundraSubpolar

TemperateConiferous forest

Desert

Deciduous forest

GrasslandChaparral Tropical

Ho

t

DesertW

et Rain forest SavannaTropical

seasonal forest

Dry

Scrubland

There Are Three Major Types of Deserts

Tropical deserts Temperate deserts Cold deserts

Fragile ecosystems• Hundreds of years for soil to recover from

disturbances• Slow plant growth• Low species diversity• Slow nutrient recycling (Why?)• Lack of water

Climatographs of 3 Types of Deserts

Staying Alive in the Desert Plant adaptations

• Drop leaves or no leaves• Storage of water and food in fleshy tissue

• Take in CO2 only at night

• Deep roots to tap into ground water• Waxy coating on leaves

Animal strategies and adaptations• Small, hide during the day• Dormant• Camel – stores massive amounts of water, doesn’t sweat• Don’t drink – water from break down of fats in seeds• Think coverings• Dry feces and urine

There Are Three Major Types of Grasslands

Tropical• Savanna• Grazing animals• Browsing animals

Temperate• Tall-grass prairies• Short-grass prairies

There Are Three Major Types of Grasslands Cold (arctic tundra) – treeless plains• Can be referred to as desert• Fragile biome• Nutrient poor soil • Melting of permafrost

• Release CH4 and CO2 into the atmosphere

Adaptations of plants and animals• Thick fur or feathers• Living underground• Low growing plants

Alpine tundra – below permafrost snow line on mountains, more sunlight, more flowers

Climatographs of Tropical, Temperate, and Cold Grasslands

Temperate Shrubland: Nice Climate, Risky Place to Live

Chaparral Near the sea: nice climate• Significant human impact

Prone to fires in the dry season Maintained by fire, plants adapt with fire-resistant

roots, produce seeds that sprout after fire, use nutrients released by the fire

Soil thin and not very fertile

Chaparral Vegetation in Utah, U.S.

There Are Three Major Types of Forests (Dominated by Trees)

TROPICAL Tropical rain forests• Warm temperatures, high humidity, heavy rainfall• Dominated by broadleaf evergreen plants• Stratification of specialized plant and animal

niches• Emergent layer, canopy (most life forms),

understory, shrub layer, ground level• Little wind to spread seeds, depend on pollinators• Rapid recycling of scarce soil nutrients due to

warm, moist conditions• Immediately taken up by trees, poor soil

• Impact of human activities?

There Are Three Major Types of Forests

TEMPERATE Temperate deciduous forests• Moderate temperatures, abundant precipitation• Dominated by few species of broad-leaf trees• Drop leaves and become dormant in winter• Slow rate of decomposition: storehouse of

nutrients• Impact of human activities more than any other

biome

There Are Three Major Types of Forests

COLD Evergreen/Northern coniferous forests: boreal

and taigas• Long extremely cold and dry winters• Few species of cone-bearing evergreen trees• Low plant diversity• Slow decomposition: waxy coating on needles,

acidic soil, nutrient poor

Coastal coniferous forest/Temperate rain forests• Ample rainfall or moisture from dense ocean fog

Climatographs of Tropical, Temperate, and Cold Forests

Stratification of Specialized Plant and Animal Niches in a Tropical Rain Forest

Mountains Play Important Ecological Roles

Dramatic changes in altitude, slope, climate, soil, and vegetation

Majority of the world’s forests• Majority of world’s terrestrial biodiversity

Habitats for endemic species Sanctuaries for migrating animals (low to high) Help regulate the earth’s climate• Ice and snow reflect solar radiation back into space• Opposite – dark exposed rock absorbs energy?

Can affect sea levels Major storehouses of water - role in hydrologic cycle

Key Concept 2: How Have We Affected the Word’s Terrestrial Ecosystems?

In many areas, human activities are impairing ecological and economic services provided by the earth’s deserts, grasslands, forests, and mountains.

Fig. 7-20, p. 158

NATURAL CAPITAL DEGRADATION

Major Human Impacts on Terrestrial Ecosystems

Deserts Grasslands Forests Mountains

Large desert cities Conversion to cropland

Clearing for agriculture, livestock grazing, timber, and urban development

Agriculture

Soil destruction by off-road vehicles

Timber extractionRelease of CO2 to atmosphere from burning grassland Conversion of

diverse forests to tree plantations

Hydroelectric dams and reservoirs

Mineral extraction

Soil salinization from irrigation Increasing tourism

Overgrazing by livestockDepletion of

groundwaterDamage from off-road vehicles

Urban air pollutionIncreased ultraviolet radiation from ozone depletionLand disturbance

and pollution from mineral extraction

Oil production and off-road vehicles in arctic tundra

Pollution of forest streams

Soil damage from off-road vehicles