Basic EcologyJohn Herron

The Nature Conservancy – Texas Chapter

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conserve

The Nature Conservancy

lands and waters

The mission of

is to

the

on which

depends.

Biodiversity and The Nature Conservancy

all life

TNC 5 Major Habitats

TNC Conservation Tools

Land acquisition

Conservation

easements

Demonstration projects

Prescribed fire

Habitat restoration

Species surveys

Ecology - defined

The study of Nature that deals with inter-

relationships, or the dependence of all living

things on all other living things and their

surroundings.

The study of the relationships of organisms to

their environment and to one another. (Brewer

1994)

The word ecology derives from the Greek words

oikos, which means “house,” and logos, which

means “discussion or study.”

Ecology

The study of living systems

– Aquatic ecology

– Forest ecology

– Field ecology

– Experimental ecology

– Population ecology

– Community ecology

– Behavorial ecology

„Ecology‟ Encompasses…

Physical environment

Organisms – species, populations, communities, ecosystems

Inter-relationships

– Predator-prey; consumers

– Competition

Nature is dynamic

– Change, flows, cycles, adaptation, selection, evolution.

– Balance

Includes humans

Understand the 7 Principles of Ecology

1. The plan or producer, the grazing animal or consumer and

the intrinsic value of a healthy ecosystem needs to be looked

at together, not separately.

2. The natural resource manager should understand the change

and know it has an influence on all of his management

decisions.

3. For every action on the land there are multiple reactions.

4. Nature abhors a void and provides plants through the

process of primary and secondary succession to fill the

openess.

5. Humans have found that nature knows best. Organisms

which are suited and adapted to change occupy the site.

6. Everything must go somewhere.

7. There is no such thing as a free lunch.

• Landscape Structure and Function

• Biotic Diversity

• Species Flow

• Nutrient Redistribution

• Energy Flow

• Landscape Change

• Landscape Stability

• Biotic Diversity

Sandor, M. 2004.

http://quizlet.com/2659795/7-principles-in-landscape-ecology-flash-cards/

Seven Principles of Landscape Ecology

Laws of Ecology

• All things are interconnected

• Everything goes somewhere

• There‟s no such thing as a free lunch

• Nature bats last

Callenbach, E. 2008. Ecology: A pocket guide.

Environment = Physical Factors

• Sun

– Weather/Climate

– Wind

– Currents

– Temperature/Heat

• Moon - Tides

• Water

• Minerals/Soils

= „Abiotic‟

Scale – Levels of organization in Ecology

• Populations

• Communities

• Ecosystems

• Biosphere

Individual - A single member of a species

Natural Selection

• Evolution – species change over

time

• Natural selections works at the

individual level

• Individuals vary

• Individuals with desirable traits

survive better

• If those traits are inheritable, they

are passed on to descendents

• As a result, those populations

changes

Population - A group of organisms of the

same species occupying a particular space at

a particular time

Population Dynamics

Population growth– Immigration

– Emigration

– Mortality

– Reproduction

Growth rate

Density

Carrying capacity

Dispersion and Movement

CARRYING CAPACITY - The maximum number of

individuals of a given species that a habitat

can sustain indefinitely.

Candy Island

0

10

20

30

40

50

60

70

1 2 3 4

Exp

25%

50%

Candy Island

0

10

20

30

40

50

60

70

1 2 3 4

Exp

25%

50%

Population Growth

Carrying

Capacity (K)

Exponential vs. Logistic growth

Communities

Populations of different species occupying a

certain area (i.e. plants, birds, fish, insects,

etc.)

Communities

• Structure

• Composition

• Energy Flow

• Production

• Nutrient Cycles

Community Structure

Capable of

producing their

own food…

primarily via

photosynthesis

Producers (Autotrophs)

Obtain energy

by feeding

on vegetation

Herbivores (Primary Consumers)

Obtain energy

by feeding

on herbivores

Primary Carnivores(Secondary Consumers)

Obtain energy

from dead plants

and animals

Detritivores (Decomposers)

Plants

Cricket GrasshopperField Mouse

ScorpionToadPraying

Mantis

Red Shouldered

Hawk

Coachwhip MockingbirdWhiptail

Food Chain

Mockingbird

Plants

Cricket GrasshopperField Mouse

ScorpionToadPraying

Mantis

Red Shouldered

Hawk

Coachwhip Whiptail

Food Web

Elements of a food web on a native

grassland.Sun

Red-tailed hawk

Wolf

FoxJackrabbit

Bison

Decomposers

Mouse

Grass

GrasshopperPrairie chicken

P 1,500,000

H 200,000

C1 90,000

C2=1

Grassland (Summer)

(Individuals per 0.1 hectare)

General pattern in nature: there are many more plants than

herbivores, greater numbers of herbivores than carnivores, seldom

more than a few top carnivores.

Pyramid of Numbers

Hydrologic Cycle

Carbon Cycle

Nitrogen Cycle

Other Ecological Concepts

• Variation

• Habitat

• Adaptation

– Niche

• Production

• Succession

Ecological Succession

Gradual progression of plants that colonize a

site over time.

Succession

The relationship between prairie-to-forest

succession and grouse species.

Prairie

chicken

Sharp-tailed

grouse

Ruffed

grouse

Spruce

grouse

Ecosystems

• An ecosystem consists of organisms from

many different species living together in a

region that are connected by the flow of

energy, nutrients, and matter that occurs as

the organisms of different species interact

with one another.• (Microsoft® Encarta® Encyclopedia 2002)

• Is a self-sustaining system involving the

interaction of living and nonliving

elements in a manner which sustains life.

Local Ecosystems

Woodland

Grassland

Riparian

Wetland

Aquatic

Landscapes

Interacting

ecosystems

across

a relatively small

geographic scale

"…game can be restored by the creative

use of the same tools which have

heretofore destroyed it - ax, plow, cow,

fire, and gun."

Aldo Leopold, Game Management, 1933.

Ecosystem management

Ecological Restoration

- Restore natural processes

- Prescribed burning

- Selective mowing

- Managed grazing

- Seasonal water flows

Prescribed burning

When we contemplate the whole globe as one great dewdrop, striped and dotted with continents and islands, flying through space with all other stars all singing and shining together as one, the whole universe appears as an infinite storm of beauty.

John Muir (1838-1914)Founder, Sierra Club

Biodiversity

John HerronThe Nature Conservancy

Austin, TX

Biological Diversity

The variety of life forms: the different plants,

animals and microorganisms, the genes they

contain, and the ecosystems they form. It is

usually considered at three levels: genetic

diversity, species diversity and ecosystem

diversity.

Kinds of Biodiversity

Species

– Species numbers

– Species richness

– Taxonomic diversity

Genetic

Habitat/Eco-systems

Species Diversity

Mammals – 4,000

Birds – 9,040

Amphibians – 4,184

Reptiles – 6,300

Fish – 19, 056

Plants – 248,428

Insects – 751,000

Texas Biodiversity

Mammals Birds Herps Fish Total % Total

Nongame 122 509 178 157 966 81%

Game 20 47 1 30 98 8%

T & E 20 28 33 26 107 9%

Extinct 6 6 1 8 21 2%

TOTAL 168 590 213 221 1192 100%

TX Only 10 49 44 23 126 11%

Relative Biodiversity

Univ. of Sydney

http://bugs.bio.usyd.edu.a

u/Entomology/importance

/imagePages/speciesSca

pe.html

Species-scape

Univ. of Sydney http://bugs.bio.usyd.edu.au/Entomology/importance/imagePages/speciesScape.html

From: WWF, http://worldwildlife.org/science/pubs/bioscience.pdf

Texas Vertebrate Diversity by Region

Texas – Biotic Crossroads

Schmidly, 2001

NatureServe, States of the Union

Figure 27. Texas

Environmental Resource

Stewards (TERS): Texas

Ecological Assessment

Protocol (TEAP) Results Pilot

Project. U.S. EPA. 2005

Changes in Species Status in Texas

Schmidly, 2001

Biodiversity is determined by

….

• Latitude

• Elevation

• Patch size

From:

http://botany1.bio.utk.edu/botany120lect/Biomes/biomemap.htm

Major Terrestrial Biomes of the World

• Ice

• Tundra

• Taiga

• Grassland

• Temperate Forest

• Chaparral

• Savanna

• Desert

• Mountain

• Tropical Rainforest

Biomes

From: Taggart, R.E., http://taggart.glg.msu.edu/bs110/biomes.htm

Texas Birds and their

Habitat

Above Canopy Species

Vultures Hawks Swallows

Swifts

Canopy

Owls Woodpeckers Vireos Thrushes

Nuthatches Tanagers Warblers

Creepers

Midstory

Warblers Jays Vireos

Chickadees Cardinals Kinglets

Understory

Mockingbirds Bluebirds

Wrens Doves

CanopyJunipers Hickories

Pines Oaks

Cedars Elms

Maples Pecans

MidstoryAsh

Maples

Sweetgum

Hackberries

UnderstoryTall ShrubsLow ShrubsDogwoods Agaritas

Viburnums Yaupons

Hawthorns Wax Myrtles

Ground CoverPrairie WetlandGramas Sedges

Bluestems Rushes

Paspalums Cattails

Ground CoverSparrows ShorebirdsWaterfowl Wadingbirds

Island Biogeography

Size of island &

Distance between islands

Determines

»Species diversity

»Extinction rates

»Immigration/Emigration ability

Applies to virtual islands!!! (habitat fragments)

McArthur and Wilson (1967)

Biodiversity and Habitat Fragments

• Island biogeography applies to terrestrial habitat

„islands‟ too!

• Small habitats hold fewer species, smaller

populations

• Small populations are vulnerable to extinction

due to:

– environmental changes

– natural disasters

– random chance

Habitat Fragmentation

When habitat is divided

into smaller sections

Some species benefit,

others are harmed

Edge Effect and Fragmentation

•Increased edge effect

•Increasing generalists

•Increased parasitism

•Increased predation

•Specialists lost

•“Ecological trap”

FRAGMENTATION AND EDGE EFFECT

Edge Effects on Wildlife

May benefit– White-tailed deer

– Some game birds

– Small mammals

– Predators

– Invader Species

May harm– Interior forest

species

– Grassland species

– Habitat specialists

– Threatened or endangered species

Managing for Edge Species

Leopold, A. 1933. Game Management.

Corridors

• To allow interspersal among islands and

fragments

• Width is important

• Corridor must be appropriate habitat type

• Results still somewhat theoretical

Designing Corridors

Worst Better Even Better Best

Connectivity

Threats to Biodiversity

• Human population effects– Habitat loss

– Habitat fragmentation

– Incompatible development

• Climate change

• Invasive/Exotic species

• Disruption of ecosystem function– Overgrazing

– Fire suppression

– Diminished freshwater flows

• Limited understanding of natural systems

Management Implications

Conserve all habitat/eco-system types

Conserve „all the pieces‟

Promote plant diversity

Promote native species

Realize genetic diversity is also important

Re-establish natural processes (flood, fire, buffers)

Consider edge effects

Interdependence ----------- Sustainability

The first requisite of intelligent tinkering is to

save all the pieces.

Aldo Leopold (1947)

“There are some who can live without wild things, and some who cannot. ... Like winds and sunsets, wild things were taken for granted until progress began to do away with them. …

…Now we face the question whether a still higher „standard of living‟ is worth its cost in things natural, wild, and free. For us of the minority, the opportunity to see geese is more important than television, and the chance to find a pasque-flower is a right as inalienable as free speech.”

Aldo Leopold

1887 - 1948

It Ain‟t Easy Being Green

…When green is all there is to be

It could make you wonder why, but why wonder why?

Wonder,

I am green and it'll do fine, it's beautiful!

And I think it's what I want to be.

Joe Rapposo, 1970

(Oh, and Kermit the Frog, too)

The Nature Conservancy

The Nature

Conservancy's efforts to

preserve the diversity of

life on Earth depends

solely on the support of

its members.

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