lecture 13 - university of colorado boulder · lecture 21: tuesday nov 13 ... –climate, water,...

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Geography 1001:

Climate & Vegetation

Instructor: Andrés Holz

Lecture 21: Tuesday Nov 13

• Logistics

– Lab K reading

– Midterm

• Today: Review for Midterm II

Lecture 13

• Global Climate Classification �� Vegetation at global scale

• Eco-logy & Bio-geography – Based on the scale of analysis� different disciplines

• Communities– Def.: Animal populations �interactions� Plant populations characterized by • 1) Physical appearance

• 2) Richness (species present)

• 3) Abundance of each species

• 4) Complex patterns of interdependence

• 5) Trophic (feeding) structure

Lecture 13

• Difference between

– Habitat (Environment where an organism

resides & Requirements in term of nutrients)

– Niche (function or role of an organism & the

way an organism obtain and sustain the factors

it needs to survive);

• e.g. red-winged blackbird� reproductive niche

• & between

– Generalists and specialists?

Lecture 13

• Plants: The Essential Biotic component …Why?

• Energy flow in Ecosystems:– Photosynthesis, NPP, & Biomass

• Abiotic Ecosystem Components– Climate, water, minerals, insolation, heat E released

– Life zones

• Limiting Factors– One abiotic component that most inhibit biotic operation, through either its lack or excess

Limiting factors –

Temperature and Precipitation

Figure 19.8

Lecture 13

2

Limiting factor

Lecture 13

Life Zones & Plant

Life Forms

Lecture 13

19.01

1) community

2) habitat

3) biome

4) life zone

A __________ is formed by interactions

among populations of living flora and fauna,

and is a subdivision of an ecosystem.

19.01

1) community

2) habitat

3) biome

4) life zone

A __________ is formed by interactions

among populations of living flora and fauna,

and is a subdivision of an ecosystem.

19.02

1) chlorophyll

2) light saturation

3) the compensation point

4) net photosynthesis

The difference between photosynthetic

production and respiration loss in plants is

called __________.

19.02

1) chlorophyll

2) light saturation

3) the compensation point

4) net photosynthesis

The difference between photosynthetic

production and respiration loss in plants is

called __________.

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19.03

1) oxygen cycles

2) floral inhibitors

3) limiting factors

4) tolerance ranges

The lack of water in desert climates or the low

temperatures at high elevations are called

__________ because they inhibit plant growth.

19.03

1) oxygen cycles

2) floral inhibitors

3) limiting factors

4) tolerance ranges

The lack of water in desert climates or the low

temperatures at high elevations are called

__________ because they inhibit plant growth.

19.06

1) Lack of disruption

2) High photosynthesis rates

3) Greater biodiversity

4) Greater biomass

__________ in an ecosystem results in

greater stability and greater productivity. 19.06

1) Lack of disruption

2) High photosynthesis rates

3) Greater biodiversity

4) Greater biomass

__________ in an ecosystem results in

greater stability and greater productivity.

19.08

1) producers

2) consumers

3) heterotrophs

4) zooplankton

Organisms that are capable of using

carbon dioxide as their sole source of

carbon are called __________.

19.08

1) producers

2) consumers

3) heterotrophs

4) zooplankton

Organisms that are capable of using

carbon dioxide as their sole source of

carbon are called __________.

4

19.09

1) food webs

2) primary productivity

3) eutrophication

4) photosynthesis

The consumption of grain-fed beef in

developed countries has led to inefficient

__________ throughout the world.

19.09

1) food webs

2) primary productivity

3) eutrophication

4) photosynthesis

The consumption of grain-fed beef in

developed countries has led to inefficient

__________ throughout the world.

PhysiognomyLecture 14

• Ecosystems essentials II

– Life Zones & Plant Life Forms

(Physiognomy): Raunkiaer life forms

(based on perennating bud)

• Phanerophytes

• Chamaephytes

• Hemicryptophytes

• Therophytes

• Geophytes

Lecture 14

• Biotic Ecosystem Operations

– Producers, Consumers, and Decomposers• autotrophs and heterotrophs

– Difference between Food Chains and Food Webs?

– Efficiency in a Food Web

– Concentration of Pollution in Food Chains

Lecture 14

• Ecosystems essentials II

– Biodiversity

• Definitions

– Species

– Ecosystem

– Genetic

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Lecture 14

• Species diversity

• Ecosystem diversity

• Genetic diversity

• BioDiversity = richness*abundance*genes*habitat diversity

Definition of biodiversityDefinition of biodiversitySpecies-Area Curves

Small------------------------------------------------Large

Size of area

Number of species

Low---------------------------High

Lecture 14

Latitudinal gradients

0-------------------------------------------------------90

Latitude

Number of species

Low---------------------------High

Lecture 14

Intermediate disturbance hypothesis

Low---------------------------------------------------High

Disturbance

Number of species

Low---------------------------High

Lecture 14

Lecture 15

• Review: Ecosystems and

Succession

– Ecosystem Stability

– Biodiversity

• Function

– Intrinsic & anthropocentric values

– Economic benefits

– (Un)Stable crop production (Ireland)

– Bio/Eco-tourism

– Future potential

Lecture 15


Succession


– Biodiversity

• Function

• Current Trends

– Habitat loss

– Species Introduction

– Over hunting

– Climate change

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Lecture 15


Succession


– Biodiversity

– Ecological Succession

• Definition

• Terrestrial Succession

– Primary

– Secondary

Lecture 15


Succession


– Biodiversity

– Ecological Succession and

Vegetation dynamics

• Terrestrial Succession

• Successional processes (& pathways)

– Relay floristics / Facilitation

– Initial floristic composition /

Tolerance

– Inhibition

Relay floristics / Facilitation Initial floristic composition / Tolerance

Inhibition

Photo: D. Kulakowski

Competition Disturbance

Stress

Competitive Strategy

e.g. Tropical forest

Stress-tolerant

strategy; e.g. Deserts

or Tundra

Ruderal strategy; Chaparral or

Rockies Conifer Forests

Primary Strategies in Plants in response to:

a) limiting factors (stress) & b) disturbance

(Grime’s Triangle)

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Lecture 16

Review:

• Ecological Succession

– Forest development (4 stages)

• Stand initiation

• Stem exclusion

• Understory reinitiation

• Old growth

– Comparison between Early-

versus Late-Stages of succession

(of Forest Development)

• Attributes & Characteristics

HighLowPlant Species Diversity

LowHighRate of Net Primary Productivity

GreatMinorRole of Decomposers in Cycling

Nutrients to Plants

Living Biomass

and LitterLitter and SoilSite of Nutrient Storage

HighLowPhotosynthetic Efficiency of Dominant

Plants at Low Light

Poorly dispersedWell dispersedSeed Dispersal Characteristics of

Dominant Plants

LongShortPlant Longevity

LargeSmallPlant Biomass

Late Stages of

Succession

Early Stages of

Succession Attribute

Lecture 16

Review:

• Ecological Succession

– Gap phase dynamics

• Tree regeneration is dependent on

canopy openings

– Continuous regeneration mode

(more rare)

• Shade tolerant species can complete

their life cycle beneath a relatively

closed forest canopy.

Lecture 16

Review:

• Vegetation dynamics concepts

– A bit of history (Clements versus

Gleason):

• Clements

– High degree of integration in a plant

community, as a complex organism, that

is discrete, repeatable, and recognizable

– Succession is a highly predictable

sequence of “life stages” of an

organisms called community, which

develops into a stable, endpoint called

climax

Lecture 16

Review:

• Vegetation dynamics concepts

– A bit of history (Clements versus

Gleason):

• Gleason

– Plant community is not discrete, or easily

recognized. Thus, vegetation cannot be

perfectly classified

– Dispersal of seeds and recruitment

occurs at different rates; Site acts as a

filter so that only certain species can

survive at a particular site

– Succession is not highly predictable as

Clements argued.

Vegetation Dynamics &

Climax Concepts

• A bit of history of theory (Clements versus Gleason)

• “Recent” recognition of role of disturbances, which interrupt the succession, provided framework to interpret studies that disagree with climax.

• Historical Shift from climax/ equilibrium to non-equilibrium ideas (late 1970s-mid1980s)

Lecture 16

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Vegetation Dynamics Concepts

• Frequent

disturbances

promote spatial

heterogeneity

Lecture 16

Photo: D. Kulakowski

Patch dynamics

Lecture 17

Review:

• Fire Ecology– Influences on fires

• Fuels

• Weather

• Topography

– Fire Regime and Types of Fire• Size

• Intensity

• Severity (Fire severity is a fire effect used as substitute for intensity)

– Low, High, & Mixed severity

• Frequency

» Frequent & Severity relationship

Influences on fires - Topography

Fast

Slow

Frequency

Infrequent---------------------------Frequent

Frequency

Severity

Low------------------High

Lecture 17

Review:

• Fire Ecology

– Fire Regime and Types of Fire

• Three basic fire types:

– Surface fires

– Ground fires

– Crown fires (a fire that burns in the

canopy of live and dead foliage and

branches)—three types:

» Active, Passive, & Independent

Crown Fire

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Lecture 17

Review:

• Fire Ecology

– Plant adaptations to fires

• Avoid fire damage

– Fire-resistant foliage (e.g. low resin

content)

– Thick fire-resistant bark

– Evanescent lower branches

• Recover following fire damage

– Sprouting behavior

• Colonize after fire

» Post-fire germination (scarification of

seed, ability to germinate and survive

in open post-fire sites)

» Cone serotiny

Lecture 17

Review:

• Fire Ecology– Fire suppression

• Healthy Forest Restoration Act

• Fire frequency and fire suppression

• Main points

– Human perceptions of ecosystems are often on time scales that are shorter that these fluctuations

– Ecosystems are dynamic and change is to be expected

– There is no single snapshot that can describe how a healthy ecosystem should look

– The same restoration strategies should not be applied across the country ‘s different ecosystems

Fire frequency and fire suppression

1700 1800 1900 2000

Year

Frequent fires:

Infrequent fires:

Lecture 18Review:

• What is a biome?

– Large (global patterns), stable terrestrial ecosystem

characterize by a specific plant and animal communities, yet

named after dominant vegetation

– Biomes can have disjunctive or separate distributions, yet are

assemblages of different, but similar looking species

– Rooted in the idea of “climax vegetation” **Climax = final

steady state; however, most ecologists think of ecosystems as

dynamic, rather than reaching a stable state. Thus, Biomes

integrate concepts like disturbance and the modification of

disturbance regimes by humans

Lecture 18Review:

• Criteria and/or Characteristics

in different biomes

– Vegetation structure: shape,

layers

– Productivity (Biomass)

– Biodiversity

– Distribution: geographic extent

– Climate: temperature and

precipitation trends

– Soils

– Disturbance regimes

Lecture 18Review:

• Biomes

– Forested

• Tropical Rainforest

• Midlatitude Deciduous Forest

• Needle leaf Forest

• Temperate Rain Forest

– Non-Forested

• Mediterranean Shrublands

• Grasslands

• Deserts

• Tundra

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Lecture 18Review:

• Equatorial and Tropical Rain

Forests

– Veg Structure:

• Complex

• multi-layered

• large bases & shallow roots

• Sparse understory (not much light)

• Epiphytes and Lianas

• Very high biomass and productivity

• Very high in biodiversity

Lecture 18Review:


Forests

– Soils are nutrient poor

– Distribution: ~0-20 N & S lat

– Climate

• Low daylight variation

• High insolation

• Lots of precipitation

• Year round warm temperatures

• No distinct seasons

• Tropical Seasonal Forest and Scrub

Lecture 18Review:


Forests

– Disturbance

• Natural

– blow-down, not much fire

• Human: Forest clearing

– Slash and burn agriculture

– Lots of erosion (poor & shallow

soils!)

– Forested Vegetation tends not to

come back (only after hundreds to

couple of thousands of year)

Lecture 18Review:

• Mid-latitude Broadleaf Deciduous

Forests

– Adapted to distinct seasons, plentiful

moisture, summer high precipitation

– Structure

• Moderately complex

• Mainly deciduous trees

• Species: Maple, Oak, Beech, pine,

hemlock

• A few vines and shrubs

• Many herbs (spring ephemerals)

– Ephemeral means brief

– Concentrate growth and flowering in early

spring before leaves come out

– Takes advantage of sunlight

Lecture 18Review:

• Mid-latitude Broadleaf

Deciduous Forests

– High biomass and biodiversity,

but less than tropical rain forests

– Soils are “average”. Fairly nutrient

poor.

– Distribution

• Central Europe, East coastal Asia, &

East coast US

– Climate

• Distinct, predictable seasons

• Cold winters, warm summers

• Max precipitation in summer

Lecture 18Review:

• Mid-latitude Broadleaf

Deciduous Forests

– Disturbance

• Treefall Gaps (winds�� Hurricanes)

• Infrequent fires

• Floods (Floodplain forests)

• Insects and disease

• Humans: logging, clearing for

agriculture, development

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Lecture 18Review:

• Needle-leaf Evergreen Forests

Adapted to harsh conditions: cold, snow, periods of drought, and unexpected weather changes– Structure

• Not complex

• Lacks sub-canopy

• Canopy is open to dense

• Species: Spruce/Fir, Pine, Larch

• Understory: dense to little or none, shrubs, herbs and small trees

• Low diversity, Low productivity

• Biomass varies: (Sequoias vs. lodgepole pine)

Two types of Needle-leaf Forests

Montane Forests

• Found at higher

elevations

• Range of types from

open pine forests to

denser spruce/fir

• Growing season may

or may not be long

Boreal Forests

• Found only in

northern hemisphere

• 45-65 North Latitudes

• Band across the

globe: circumboreal

• Short growing season

• Mainly spruce/fir

Lecture 18Review:


– Climate

• Climate can be harsh: cold, lots of

snow, periods of drought

• Climate can be variable, especially in

montane forests (warm days in

winter, early/late season snows

Lecture 18Review:


– Disturbance

• Natural Disturbance

– Wind (big blow down events)

– Fire (varies in intensity and frequency)

– Insect outbreaks

– Human Disturbance– Logging

– Changes in Fire regime (accelerating or

slowing down)

– Development (housing, mining)

Needle-leaf Forests

• Question: how are needle-leaf evergreen

trees adapted to harsh, variable

environments?

• Evergreen: can utilize sunlight any time of

year

• Needle-leaf: better at shedding snow and

wind, deal with dry conditions better than

broadleaves

Lecture 19Review:

Temperate Rain Forests

• Huge trees, moderate

maritime climate, lots of

precipitation

– Structure

• Tall, dense canopy of needle-&

small broad-leaf evergreens

• Deciduous &/or evergreen sub-

canopy

• High biomass and productivity

• Not much canopy diversity. Higher

sub-canopy diversity

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Lecture 19Review:




precipitation

– Distribution

• West Coasts: Northern California to

SE Alaska

• Southern tip of New Zealand

• Southern Chile (mixed evergreen

needle-leaf and broadleaf evergreen

trees)

Lecture 19Review:




precipitation

– Climate

• “Marine West Coast”

• Lots of precipitation, winter high.

• Drier summers

• Mild temps (oceanic influence):

Lecture 19Review:


• Huge trees, moderate maritime climate, lots of precipitation– Disturbance

• Windfall

– Nursery logs

• Infrequent fire, only in extreme dry years

• Infrequent landslide due

– to extreme precipitation

– earthquakes

– Volcano eruptions

• Humans: Logging, Clearing for development

Lecture 19Review:

Non-Forested Biomes


– Structure

• Shrubs

• Dominant species: Chamise,

Ceanothus, Mountain Mahogany,

Oaks

• “Sclerophyllous” Vegetation: hard

leathery leaves

• Leaves are evergreen or drought-

deciduous and generally very small

Lecture 19Review:

Non-Forested Biomes


– Mediterranean Shrublands: Structure

Two different types in California

• Coastal Sage Scrub: 2-layered

– Shrubs = 1 m tall spaced far apart

– Lots of grasses and forbs “understory”

– Located along the coast (low elevation)

• Chaparral: a thick wall of shrubs

– 2 to 5 dominant shrub species

– Lacks much understory in mature stage

– Located at higher elevations than C.S.S.

Lecture 19Review:

Non-Forested Biomes


– Distribution

• 5 disjunct locations

located on west coasts of

continents between 30-40 degrees

latitude

– Southern California: Chaparral,

C.S.S.

– South America (Chile): Matorral

– Australia: Heath

– South Africa: Fynbos

– Mediterranean Sea: Maquis or

Matorral

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Lecture 19Review:

Non-Forested Biomes


– Climate

• Winter high in precipitation

• Definite summer drought

• Temperatures mild in winter, mild to

hot in summer

• Similar patterns to Temperate Rain

Forest

Lecture 19Review:

Non-Forested Biomes


– Disturbance

• Landslides, Floods

• Fire is very important!

• Frequent fires

• Re-sprouting shrubs (quick return

interval)

• “Fire Followers”

• Human disturbances: clearing for

development, changing fire regime

(suppression vs acceleration)

Lecture 20Review:

Non-Forested Biomes

• Deserts

Characterized by very low

precipitation

– Distribution

• Subtropical High Pressure Zones

(20-35 degrees N and S)

• Rainshadow areas of Mountain

Ranges

Lecture 20Review:

Non-Forested Biomes: Deserts

– Warm Deserts• Lower latitudes, warmer

temperatures

• Subtropical High Pressure Zones

• Moderately Complex Structure

– Shrub layer

– Annual grasses and forbs (after

rains)

– “Tree” layer: Saguaro cacti, Joshua

Trees

• Moderate biodiversity

• Low productivity, low biomass

Lecture 20Review:


• Cold Deserts

– Cold Winters, Warm Summers

– Rainshadow Deserts

– Low diversity, productivity, and

biomass

– Lacks a “tree” layer

– Few cacti

– Dominated by shrubs and

grasses

Review: Non-Forested Biomes: Deserts

Case studies of North American Deserts

DistributionDistributionPrecipitation regimePrecipitation regimeType of Type of

DesertsDeserts

Arizona, California, Northern MexicoTwo precipitation highs

Summer & Winter

WarmSonoran

Rainshadow desert; Eastern Oregon, Nevada,

Utah, parts of Idaho and Wyoming

Winter highColdGreat Basin

Southeastern California, Southern Nevada,

Northwestern Arizona

Winter highWarm/ColdMojave

Texas, New Mexico, Northern MexicoSummer high precipitation

(Monsoon)

WarmChihuahuan

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Lecture 20Review:


• Disturbances

– Wind and water erosion

– Flooding during rain events

– Not much fire historically

– Human

• Off road vehicles

• Changes in fire regime

• Grazing

• Mining

Lecture 20Review:


Invasive Species Case study

• Cheat Grass (Bromus tectorum)

– Grows between shrubs

– Highly flammable

– Shrubs burn, don’t come back

– Cheat Grass thrives with fire

– Sagebrush shrubland � Cheat grass

– A “positive feedback”

Lecture 20Review:

Non-Forested Biomes: Grasslands

• Tallgrass vs. Shortgrass prairie: A precipitation gradient

Drier than

Tall Grass

Prairie

Wetter than

Short Grass

Prairie

Precipitation Precipitation

regimeregime

Biomass and

productivity

fairly low

Moderate to

low biomass,

but high

productivity

Biomass & Biomass &

ProductivityProductivityHuman Human

inducedinduced--

disturbancedisturbance

Soils Soils

qualityqualityFire regimeFire regimeType of Type of

GrasslandGrassland

Grazing and

agriculture

(irrigation

needed)

Not as rich

as tall grass

Less fire because

less fuelShortgrass

Dominated by

agriculture

Best soils in

the world

(Mollisols)

Historically

maintained by fire

(2-4 year interval)

Without fire, may

become a

deciduous forest

Tallgrass

Question: Why might remnant tall grass

prairie exist near Boulder?

• Irrigation ditches

• (Soil is 50% rock, so half as much

precipitation = same soil moisture level)

Lecture 20Review:

Non-Forested Biomes: Tundra

• Properties

– Vegetation consists of grasses, sedges, forbs, and low

shrubs (willows)

– Biomass and productivity are low

– Biodiversity is low/moderate

– Vegetation adapted to extreme cold

Lecture 20Review: Non-Forested Biomes: Tundra

– Arctic vs. Alpine Tundra

High

Usually low

ElevationElevation

Low/Med/High

High

LatitudeLatitude DisturbanceDisturbanceTemperatuTemperatu

re rangere range

Precipitation Precipitation

regimeregime

Type of Type of

TundraTundra

WindLarge temp

range

Precipitation

tends to be high

(mountain

snows)

Alpine

Permafrost

(active layer)

thawing, fires

Large

temperatur

e ranges

Precipitation

may be lowArctic

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• Question: What is the fundamental

environmental difference between

arctic and alpine tundra?

• Insolation: Alpine tundra can be found

at any latitude, so it can have high

levels of solar radiation

Altiplano or High Plateau, Chile �

Photo: A. Holz

20.01

1) Warm Desert and Semidesert

2) Cold Desert and Semidesert

3) Midlatitude Grasslands

4) Tropical Seasonal Forest and Scrub

The __________ biome is associated with sagebrush,

scrub vegetation, low diversity, low productivity and is

located in western North America.

20.01





The __________ biome is associated with sagebrush,

scrub vegetation, low diversity, low productivity and is

located in western North America.

20.02



3) Arctic and Alpine Tundra


At lower latitudes, the __________ biome

occurs only at high altitudes.

20.02



3) Arctic and Alpine Tundra


At lower latitudes, the __________ biome

occurs only at high altitudes.20.03

1) Midlatitude Broadleaf and Mixed Forest

2) Needleleaf Forestand Montane Forest

3) MediterraneanShrubland


The __________ biome is associated with bison, and it is

dominated by either agriculture or grazing due to its great

soils; thus it is the one most modified by human activities.

16

20.03


2) Needleleaf Forestand Montane Forest

3) MediterraneanShrubland


The __________ biome is associated with bison, and it is

dominated by either agriculture or grazing due to its great

soils; thus it is the one most modified by human activities.

20.04


2) Temperate Rainforest

3) Needleleaf Forest and Montane Forest

4) Mediterranean Shrubland

The __________ biome is associated with

simple vegetation structure, low diversity, & low

productivity potential.

20.04




4) Mediterranean Shrubland

The __________ biome is associated with

simple vegetation structure, low diversity, & low

productivity potential.

20.05

1) Equatorial and Tropical Rainforest


3) Tropical Savanna


The __________ biome is associated with few

vines and shrubs, and various ephemeral herbs

during spring.

20.05



3) Tropical Savanna


The __________ biome is associated with few

vines and shrubs, and various ephemeral herbs

during spring.

20.07

1) alpine tundra

2) arctic tundra

3) cold desertand semidesert

4) mixed forest

This photograph shows __________.

17

20.07

1) alpine tundra

2) arctic tundra

3) cold desertand semidesert

4) mixed forest

This photograph shows __________. 20.09





This photograph shows the _______ biome,

which includes the Earth’s tallest trees.

20.09





This photograph shows the _______ biome,

which includes the Earth’s tallest trees. 20.10

1) drought-adapted, and also contains chaparral vegetation

2) characterized by mollisols and high npp

3) characterized by succulents and dry shrubs

4) characterized by lianas and epiphytes as well as grasses

The biome in this photograph is

__________.

20.10

1) drought-adapted, and also contains chaparral vegetation

2) characterized by mollisols and high npp

3) characterized by succulents and dry shrubs

4) characterized by lianas and epiphytes as well as grasses

The biome in this photograph is

__________.

lecture 13 - university of colorado boulder · lecture 21: tuesday nov 13 ... –climate, water,...

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