Chapter 5 TERRESTRIAL BIOMES - · PDF fileChapter 5 TERRESTRIAL BIOMES. 2 ... Large Herbivores...

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Chapter 5

TERRESTRIAL

BIOMES

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Outline

• Terrestrial Biomes

Tundra

Coniferous, Deciduous and Rain Forest

Grassland, Savanna, Chaparral

Desert

• Marine Ecosystems

Coasts, Open Ocean

• Freshwater Ecosystems

Lakes, Rivers, Wetlands

• Human Disturbance

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TERRESTRIAL BIOMES

• BIOME – an area sharing similar climate,

topographic and soil conditions, and thus the

same general type of biological communities

• TEMPERATURE and PRECIPITATION are

among the most important abiotic factors

determining biome distribution.

Many temperature-controlled biomes occur in

latitudinal bands.

Vegetation is also affected by altitude.

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BIOMES

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• Temperature and precipitation also change with altitude. As you go UP a mountain, it gets cooler and wetter. VERTICAL ZONATION is a term applied to vegetation zones defined by altitude.

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TUNDRA

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TUNDRA

• LATITUDE/ALTITUDE:

ARCTIC - High Latitudes 600N/S

ALPINE - High Altitudes (mountaintops)

• AVERAGE RAINFALL: <10cm/year

• SEASONAL VARIATIONS: below freezing most of the year, midsummer growth. -20 - 100C

• SOIL CHARACTERISTICS: poor in nutrients, slow decomposition, **PERMAFROST

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TUNDRA• DOMINANT PLANT SPECIES & ADAPTATIONS:

TREELESS, Lichens, mosses, grasses, sedges, Herbaceous plants, small low growing to conserve heat, 2-3 month growing season

ALPINE plants have deep pigmentation and leathery leaves to protect against UV radiation

• DOMINANT ANIMAL SPECIES & ADAPTATIONS

Seasonal insects, migratory birds, migratory herbivores (caribou, sheep)

Predators (fox, wolves, bear, owl)

Many rodents (hare, mice, voles) burrows

Color change for seasons (white – brown)

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TUNDRA• HUMAN DISTURBANCE:

Global climate change – affecting permafrost and seasonal growing time

Oil & gas drilling – pipelines, roads, vehicles

Air pollution gathers in high latitude areas

• OTHER:

Low productivity - short growing season

Arctic – 24 hr daylight in summer

PERMAFROST – soil is ALWAYS frozen, inhibits large roots/large plant growth

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CONIFEROUS / BOREAL FOREST / TAIGA

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TEMPERATE

RAINFOREST

REDWOODS OF

CALIFORNIA

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ARCTIC (Boreal) - High Latitudes 500-600N Northern Hemi. ONLY!

ALPINE - High Altitudes (Below tundra)

• AVERAGE RAINFALL: 50-250cm/year – varies greatly depending on region

• SEASONAL VARIATIONS: mostly cold, very short growing season. -5 - 150C

• SOIL CHARACTERISTICS: poor, acidic, slow decomposition, frozen most of year

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• DOMINANT PLANT SPECIES & ADAPTATIONS:

LOW diversity, Cone bearing, Pines, evergreens (hemlock, spruce, cedar, fir) California Redwoods

Cold & drought tolerant, Needles are leaves –thin and waxy to reduce water loss

May contain some deciduous trees (birch, aspen)


Migratory songbirds, owls, woodpeckers

Moose, deer, wolves, lynx, bear – thick coats, hibernate, herbivores feed on moss & lichen in winter months

Small rodents store food, burrow under snow


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CONIFEROUS / BOREAL FOREST / TAIGA• HUMAN DISTURBANCE:

Deforestation – most wood in NA

Spotted Owl controversy in Redwoods

Mining, dams

• OTHER:

Temperate Rainforest – Redwoods of west coast – high rainfall

Some conifers require fire to open cones and reduce competition for light

TAIGA – ecotone between Boreal Forest and the Tundra – some trees, thinning toward tundra

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TEMPERATE DECIDUOUS FORESTS

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TEMPERATE DECIDUOUS FOREST

• LATITUDE/ALTITUDE: 300-550N/S

• AVERAGE RAINFALL: 75-250 cm/year

Distributed equally throughout the year

• SEASONAL VARIATIONS: usually 4 distinct seasons 00-200C

• SOIL CHARACTERISTICS: HIGH in nutrients, RICH, good amount of humus, leaf litter

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TEMPERATE DECIDUOUS FOREST• DOMINANT PLANT SPECIES & ADAPTATIONS:

Deciduous – leaves fall off in the winter

Broadleaf trees, hardwood trees – oaks, maples, beech

Dormant period in winter, regrowth of leaves in the spring required a lot of energy (stored)

Ferns, lichens, mosses on moist ground


High diversity of songbirds, insects, amphibians

Fox, bear, deer, rabbits, squirrels, bobcat

Animals may migrate, store food, hibernate in winter months

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TEMPERATE DECIDUOUS FOREST• HUMAN DISTURBANCE:

Deforestation – since arrival of settlers –lumber, firewood, development, agricultural lands and industrial uses

• OTHER:

Re-growth after disturbance tends to be fast due to long growing season

Vernal (springtime) ponds support amphibian & insect populations

THIS IS OUR BIOME!!!

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WOODLAND / SCRUBLAND / CHAPARRAL

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WOODLAND / SCRUBLAND / CHAPARRAL


~ 400N/S usually coastal

• AVERAGE RAINFALL: 40-60cm/year

• SEASONAL VARIATIONS: cool moist winters, hot dry summers 00-380C

• SOIL CHARACTERISTICS: poor , shallow, rocky

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WOODLAND / SCRUBLAND / CHAPARRAL• DOMINANT PLANT SPECIES & ADAPTATIONS:

Drought adapted shrubs, trees, grasses

Grow in clusters

Small leathery leaves with thick waxy layers

Annual spring flowers, or after fire


Drought tolerant – rabbits, kangaroo rats, mule deer, lizards, sheep, fox, coyote

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WOODLAND / SCRUBLAND / CHAPARRAL• HUMAN DISTURBANCE:

Human Development – climate is generally good – not too cold, not too rainy -

• OTHER:

Periodic fires necessary for plant reproduction - seeds require heat, or charring to sprout

Considered “Hot Spots” due to high biodiversity in a small area

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TROPICAL RAIN FOREST

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TROPICAL RAIN FOREST


20-300N/S

At high altitudes called “Mist Forests”

• AVERAGE RAINFALL: 200+cm/year

• SEASONAL VARIATIONS: warm and moist all year – very little variation

• SOIL CHARACTERISTICS: poor in nutrients, old, thin. Decomposition is extremely fast and nutrients are immediately taken up and stored in plants

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TROPICAL RAIN FOREST• DOMINANT PLANT SPECIES & ADAPTATIONS:

Broadleaf evergreens – photosynthesize all year

Epiphytic plants, vines

Multi-story canopy – trees are shade tolerant

Trees form BUTTRESS ROOTS for support - soil is thin, heavy rains, roots are shallow


HIGH BIODIVERSITY – Insects, birds, reptiles, amphibians, mammals – most are ARBOREAL

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TROPICAL RAIN FOREST• HUMAN DISTURBANCE:

Deforestation – agriculture, mining, lumber, livestock grazing

Leads to loss of biodiversity

Leads to erosion (soil easily washes

away)

• OTHER:

90% of nutrients are in biomass!!

Multilayered forest

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SAVANNAS

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SAVANNAS

• LATITUDE/ALTITUDE: 20–30 0N/S

• AVERAGE RAINFALL: 50 -150 cm/year

• SEASONAL VARIATIONS: dry most of the year, rainy season 8–20 0C

• SOIL CHARACTERISTICS: generally rich

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SAVANNAS• DOMINANT PLANT SPECIES & ADAPTATIONS:

Dominated by grasses – When trees are present it is called Savanna - trees are sparse and clustered

Thorny acacia trees – small leaves, thorns on branches, drought resistant


Large Herbivores – migratory – follow rains and new grasses – wildebeest, antelope, bizon, zebra

Predators follow herbivores – lions, hyena, vultures

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SAVANNAS• HUMAN DISTURBANCE:

Overgrazing by livestock

Poaching of large animals – elephant, rhino, lion, leopard

• OTHER:

Fires during dry season – kill young trees –maintain grassland balance

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GRASSLANDS

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TEMPERATE GRASSLANDS

• LATITUDE/ALTITUDE: 30–50 0N/S

• AVERAGE RAINFALL: 25-100cm/year

• SEASONAL VARIATIONS: variable throughout the year and daily variations

• SOIL CHARACTERISTICS: RICH SOIL, lots of decaying plant material, high amounts of humus hold moisture in soil

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TEMPERATE GRASSLANDS• DOMINANT PLANT SPECIES & ADAPTATIONS:

Mixed grasses and herbaceous flowering plants (FORBS – wildflowers)

Deep root adaptations for drought and fire

Root system creates “sod” - thick mat which reduces erosion of top soil


Animals tend to burrow (no trees) – rodents, prarie dogs, ferrets, owls, fox, coyote

Large herbivores – migrate – bison, antelope, deer

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TEMPERATE GRASSLANDS• HUMAN DISTURBANCE:

Conversion for Agriculture – corn, wheat, soy

Conversion for pasture/grazing of livestock –overgrazing leads to killing of grass roots and soil erosion. Weeds and poor quality plants will persist

• OTHER:

FIRE ADAPTED COMMUNITY – needs fire to maintain grassland ecosystem.

Fire returns nutrients to soil

Fire suppression leads to shrub and tree growth which cause fires to burn hotter and longer

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DESERTS

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DESERTS


HOT - 300N/S in central regions of continents

COLD – some consider tundra areas a desert due to lack of water

• AVERAGE RAINFALL: <30cm/year rains are unpredictable and non-seasonal

• SEASONAL VARIATIONS: -50 - 300C

Daily variations: can be extremely cold at night

• SOIL CHARACTERISTICS: poor in nutrients, extremely slow to form, NOT resilient

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DESERTS• DOMINANT PLANT SPECIES & ADAPTATIONS:

SUCCULENTS - plants that store water in their leaves and/stems

Stems are green and can photosynthesize

Spines/needles are leaves – provide shade

Bloom & produce seeds rapidly (dormancy)

Absorb CO2 at night to reduce water loss


NOCTURNAL to avoid heat, deep burrows

Get moisture from plants they eat

Concentrated urine, dry feces

ESTIVATE – hibernate to avoid extreme heat

Reptiles have thick skin to reduce dehydration

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DESERTS• HUMAN DISTURBANCE:

Off road vehicles damage sensitive soils

Overgrazing – reduces roots – sands dry up quickly – blow away

• OTHER:

ALLELOPATHIC – Allelopathy – plants release chemicals/toxins from their roots to keep other plants away. This reduces competition.

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HUMAN DISTURBANCE

• By some estimates, humans preempt about 40% of net terrestrial primary productivity.

• Conversion of habitat to human use is single largest cause of biodiversity loss.

• Temperate deciduous forests are the most completely human-dominated biome.

• Tundra and Arctic Deserts are the least disturbed.

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HUMAN DISTURBANCE

Chapter 5 TERRESTRIAL BIOMES - · PDF fileChapter 5 TERRESTRIAL BIOMES. 2 ... Large Herbivores...

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