5
6 Global Interactions 2: Second Edition 7 Ecosystems at Risk: An Overview exam-style questions At the beginning of the twentieth century there were 1.6 billion people on earth and while pollution and environmental degradation were common, the problems were generally local. The world still seemed vast, and large areas remained virtually untouched by human activity. Just over 100 years later the world’s population has grown to more than 6 billion and the environmental problems that have resulted from this rapid growth now affect the whole planet. Whole ecosystems are at risk; agricultural and urban developments have degraded the planet and altered its atmosphere. As habitats are destroyed, the species of plants and animals that depend on them become extinct. These problems can only worsen as the world’s population grows to an estimated 10 billion by 2050, and the size of the global economy grows to at least five times its present size. Can this rate of population and economic growth be sustained? What about the countries of the developing world where millions of people still don’t have an acceptable standard of living? Do they have a right to the same standard of living as we in the developed world have? Can this be achieved without further environmental degradation? These are the questions that must be answered if we are to sustainably manage and protect the global environment, its habitats and biological diversity. It should not be assumed that human impact on the biophysical environment is a relatively recent event. For many thousands of years many indigenous peoples behaved in ways that transformed ecosystems and led to the extinction of many species. Such impacts were, however, usually followed by long periods of environmental stability during which the biophysical environment adjusted to the human impact. Some experts argue that the earth’s ecosystems are in fact ‘human artefacts’: ecosystems modified by thousands of years of human use. Ecosystems at Risk: An Overview unit 1.1 extended responses Analyse the biophysical interactions that lead to diverse ecosystems and their functioning. Explain the factors that place ecosystems at risk. Account for the vulnerability and resilience of ecosystems. Compare and contrast the vulnerability and resilience of two ecosystems at risk. Outline the natural and human-induced modifications that cause stress in ecosystems. Explain why it is important to manage and protect ecosystems. Evaluate the traditional and contemporary management strategies used to protect ecosystems. ‘Lost World’: treasure trove of new species found in Indonesian New Guinea Scientists don’t have to venture into space to discover new worlds. In late 2005, a team of Indonesian, Australian and US scientists spent nearly a month in the Foja Mountains on the western side of New Guinea (the part of the island belonging to Indonesia) surveying the area’s wildlife and plants. Within minutes of arriving in the area, the scientists encountered a bizarre, orange-faced honeyeater bird. It proved to be a new bird species; the first discovered in New Guinea since 1939. On the second day the scientists made another amazing discovery when a male and female Berlepsch’s six-wired bird of paradise came into their camp to perform a mating dance. Until then the homeland of this ‘lost’ bird had been unknown. It was the first time Western scientists had even seen an adult male of this species. Another surprise for the scientists was their discovery of the golden- mantled tree kangaroo. The animal is the rarest arboreal (tree-dwelling), jungle-dwelling kangaroo in the world. This was the first time this mammal was found in Indonesia, making it only the second site in the world where the species is known to exist. unit 1.1 We do not inherit the earth from our ancestors, we borrow it from our children. Native American proverb Earth provides enough to satisfy every man’s need, but not every man’s greed. Mahatma Gandhi, Indian independence leader FIGURE 2.6 Newly discovered arboreal, jungle-dwelling kangaroo. 7 Ecosystems at Risk: An Overview 6 Global Interactions 2: Second Edition Sample pages

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6G

lobal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

7Eco

syst

ems

at R

isk:

An

Ove

rvie

w

exam

-sty

le q

uest

ion

s

At

the

beg

innin

g of

the

twen

tiet

h c

entu

ry t

her

e w

ere

1.6

bill

ion

peo

ple

on e

arth

and w

hile

pol

luti

on a

nd e

nvir

onm

enta

l deg

radat

ion w

ere

com

mon

, th

e pro

ble

ms

wer

e ge

ner

ally

loc

al.

The

wor

ld s

till

seem

ed v

ast,

and lar

ge a

reas

rem

ained

vir

tual

ly

unto

uch

ed b

y hum

an a

ctiv

ity.

Just

ove

r 100 y

ears

lat

er t

he

wor

ld’s

pop

ula

tion

has

gro

wn t

o m

ore

than

6 b

illio

n a

nd t

he

envi

ronm

enta

l pro

ble

ms

that

hav

e re

sult

ed f

rom

this

rap

id

gro

wth

now

aff

ect

the

whol

e pla

net

. W

hol

e ec

osys

tem

s ar

e at

ris

k;

agri

cult

ura

l an

d u

rban

dev

elop

men

ts h

ave

deg

raded

the

pla

net

an

d a

lter

ed its

atm

ospher

e. A

s hab

itat

s ar

e des

troy

ed, th

e sp

ecie

s of

pla

nts

and a

nim

als

that

dep

end o

n t

hem

bec

ome

exti

nct

. Th

ese

pro

ble

ms

can o

nly

wor

sen a

s th

e w

orld

’s p

opula

tion

gro

ws

to a

n e

stim

ated

10 b

illio

n b

y 2050, an

d t

he

size

of

the

glob

al e

conom

y gro

ws

to a

t le

ast

five

tim

es its

pre

sent

size

. C

an

this

rat

e of

pop

ula

tion

and e

conom

ic g

row

th b

e su

stai

ned

? W

hat

ab

out

the

countr

ies

of t

he

dev

elop

ing

wor

ld w

her

e m

illio

ns

of

peo

ple

sti

ll don

’t h

ave

an a

ccep

table

sta

ndar

d o

f liv

ing?

Do

they

hav

e a

righ

t to

the

sam

e st

andar

d o

f liv

ing

as w

e in

the

dev

elop

ed

wor

ld h

ave?

Can

this

be

achie

ved w

ithou

t fu

rther

env

iron

men

tal

deg

radat

ion?

Thes

e ar

e th

e ques

tion

s th

at m

ust

be

answ

ered

if

we

are

to s

ust

ainab

ly m

anag

e an

d p

rote

ct t

he

glob

al e

nvir

onm

ent,

it

s hab

itat

s an

d b

iolo

gica

l div

ersi

ty.

It s

hou

ld n

ot b

e as

sum

ed t

hat

hum

an im

pac

t on

the

bio

phys

ical

env

iron

men

t is

a r

elat

ivel

y re

cent

even

t. F

or m

any

thou

sands

of y

ears

man

y in

dig

enou

s peo

ple

s beh

aved

in w

ays

that

tra

nsf

orm

ed e

cosy

stem

s an

d led

to

the

exti

nct

ion o

f m

any

spec

ies.

Such

im

pac

ts w

ere,

how

ever

, usu

ally

fol

low

ed b

y lo

ng

per

iods

of e

nvir

onm

enta

l st

abili

ty d

uri

ng

whic

h t

he

bio

phys

ical

en

viro

nm

ent

adju

sted

to

the

hum

an im

pac

t. S

ome

exper

ts

argu

e th

at t

he

eart

h’s

eco

syst

ems

are

in fac

t ‘h

um

an a

rtef

acts

’:

ecos

yste

ms

mod

ifie

d b

y th

ousa

nds

of y

ears

of

hum

an u

se.

Ecos

yste

ms

at

Risk

: An

Ove

rvie

w

unit 1.1

exte

nd

ed

re

spo

nse

s

Anal

yse

the

bio

phys

ical

inte

ract

ions

that

lea

d t

o div

erse

ec

osys

tem

s an

d t

hei

r fu

nct

ionin

g.

Exp

lain

the

fact

ors

that

pla

ce e

cosy

stem

s at

ris

k.

Acc

ount

for

the

vuln

erab

ility

and r

esili

ence

of

ecos

yste

ms.

Com

par

e an

d c

ontr

ast

the

vuln

erab

ility

and r

esili

ence

of

two

ecos

yste

ms

at r

isk.

O

utl

ine

the

nat

ura

l an

d h

um

an-induce

d m

odific

atio

ns

that

ca

use

str

ess

in e

cosy

stem

s.

Exp

lain

why

it is

impor

tant

to m

anag

e an

d p

rote

ct

ecos

yste

ms.

Eva

luat

e th

e tr

adit

ional

and c

onte

mpor

ary

man

agem

ent

stra

tegi

es u

sed t

o pro

tect

eco

syst

ems.

‘Lo

st W

orl

d’:

tre

asur

e tr

ove

of n

ew

spe

cie

s fo

und

in

Ind

on

esi

an N

ew G

uin

ea

Scie

ntis

ts d

on’t

have

to v

entu

re

into

spa

ce to

dis

cove

r ne

w w

orld

s.

In la

te 2

005,

a te

am o

f Ind

ones

ian,

A

ustr

alia

n an

d U

S sc

ient

ists

spe

nt

near

ly a

mon

th in

the

Foja

Mou

ntai

ns

on th

e w

este

rn s

ide

of N

ew G

uine

a (t

he p

art o

f the

isla

nd b

elon

ging

to

Ind

ones

ia) s

urve

ying

the

area

’s

wild

life

and

pla

nts.

Wit

hin

min

utes

of

arr

ivin

g in

the

area

, the

sci

enti

sts

enco

unte

red

a b

izar

re, o

rang

e-fa

ced

ho

neye

ater

bir

d. I

t pro

ved

to b

e a

new

bir

d s

peci

es; t

he fi

rst d

isco

vere

d

in N

ew G

uine

a si

nce

1939

. O

n th

e se

cond

day

the

scie

ntis

ts

mad

e an

othe

r am

azin

g d

isco

very

w

hen

a m

ale

and

fem

ale

Ber

leps

ch’s

si

x-w

ired

bir

d o

f par

adis

e ca

me

into

thei

r ca

mp

to p

erfo

rm a

mat

ing

dan

ce. U

ntil

then

the

hom

elan

d o

f th

is ‘l

ost’

bird

had

bee

n un

know

n. It

w

as th

e fi

rst t

ime

Wes

tern

sci

enti

sts

had

eve

n se

en a

n ad

ult m

ale

of th

is

spec

ies.

Ano

ther

sur

pris

e fo

r th

e sc

ient

ists

w

as th

eir

dis

cove

ry o

f the

gol

den

-m

antl

ed tr

ee k

anga

roo.

The

ani

mal

is

the

rare

st a

rbor

eal (

tree

-dw

ellin

g),

jung

le-d

wel

ling

kang

aroo

in th

e w

orld

. Thi

s w

as th

e fi r

st ti

me

this

m

amm

al w

as fo

und

in In

don

esia

, m

akin

g it

onl

y th

e se

cond

sit

e in

the

wor

ld w

here

the

spec

ies

is k

now

n to

exi

st.

unit

1.1

W

e d

o n

ot i

nh

eri

t th

e e

arth

fro

m o

ur

ance

sto

rs, w

e b

orr

ow it

fro

m o

ur c

hil

dre

n.

Na

tive

Am

eric

an

pro

verb

“ E

arth

pro

vid

es

en

oug

h to

sat

isfy

eve

ry

man

’s n

ee

d, b

ut n

ot e

very

man

’s g

ree

d.

Ma

ha

tma

Ga

nd

hi,

In

dia

n i

nd

epen

den

ce l

ead

er“

““

FIGURE 2.6

New

ly d

iscove

red a

rbore

al, jungle

-dw

elli

ng k

angaro

o.

7Eco

syst

ems

at R

isk:

An

Ove

rvie

w6

Glo

bal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

Sample

page

s

glossary 8G

lobal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

9

Eco

syst

em

s an

d th

eir

fun

ctio

nin

gW

hat

is a

n ec

osys

tem

?E

colo

gy is

the

scie

nce

that

exa

min

es th

e in

tera

ctio

ns b

etw

een

orga

nism

s an

d t

heir

livi

ng (

bio

tic)

and

non

-liv

ing

(ab

ioti

c) e

nvir

onm

ent.

The

key

w

ord

in

this

defi

nit

ion

is i

nter

acti

ons.

Gro

ups

of o

rgan

ism

s an

d t

heir

bi

ophy

sica

l en

viro

nmen

t in

tera

ct a

nd e

xcha

nge

mat

ter

and

ene

rgy.

C

olle

ctiv

ely,

they

form

an

ecol

ogic

al sy

stem

or e

cosy

stem

. Con

sequ

entl

y,

we

refe

r to

eco

syst

ems

as b

eing

dyn

amic

; th

is m

eans

tha

t th

ey a

re

cons

tant

ly c

hang

ing

and

ad

apti

ng.

By

iden

tify

ing

char

acte

rist

ic p

atte

rns

of i

nter

acti

on i

t is

pos

sibl

e to

d

isti

ngui

sh d

iffe

rent

typ

es o

f ec

osys

tem

. A

n ec

osys

tem

is,

the

refo

re,

defi

ned

as

an

id

enti

fi abl

e sy

stem

of

in

terd

epen

den

t re

lati

onsh

ips

betw

een

livin

g or

gani

sms

and

thei

r bi

ophy

sica

l env

iron

men

t.E

cosy

stem

s ar

e sy

stem

s th

roug

h w

hich

in

com

ing

sola

r en

ergy

is

cap

ture

d a

nd c

hann

elle

d t

hrou

gh a

hie

rarc

hy o

f lif

e fo

rms.

Eac

h ec

osys

tem

has

its

ow

n ch

arac

teri

stic

pla

nt a

nd a

nim

al c

omm

un

ity.

Plan

ts,

both

on

land

and

in

the

sea,

con

vert

sun

light

(vi

a a

proc

ess

know

n as

pho

tosy

nthe

sis)

into

sto

rabl

e—an

d e

dib

le—

chem

ical

ene

rgy.

A

nim

als

feed

on

thes

e pl

ants

and

on

othe

r an

imal

s. T

he q

uest

for

foo

d

is th

e ce

ntra

l org

anis

ing

prin

cipl

e w

ithi

n ec

osys

tem

s.A

n im

port

ant

feat

ure

of e

cosy

stem

s is

the

set

of

proc

esse

s by

whi

ch

nu

trie

nts

are

ret

aine

d a

nd r

ecyc

led

. L

ivin

g th

ings

do

not

crea

te n

ew

mat

ter.

Inst

ead

, the

y re

cycl

e nu

trie

nts

obta

ined

from

air

, soi

l, w

ater

and

ot

her

orga

nism

s, u

sing

sol

ar e

nerg

y to

bui

ld a

nd m

aint

ain

them

selv

es.

Vari

atio

ns in

eco

syst

ems

It is

impo

rtan

t to

not

e th

at t

he c

ompo

nent

s of

any

eco

syst

em c

an v

ary

natu

rally

or

as a

res

ult

of h

uman

int

erve

ntio

n. E

ach

vari

atio

n w

ill, i

n

abio

tic

the

non

-liv

ing

com

pon

ents

of

ecos

yste

ms,

su

ch a

s lig

ht,

soi

l, w

ater

and a

ir.aq

uati

c ec

osys

tem

a w

ater

-bas

ed e

cosy

stem

, su

ch

as a

pon

d, la

ke o

r oc

ean.

auto

trop

hic

orga

nism

an o

rgan

ism

that

m

anufa

cture

s it

s ow

n foo

d f

rom

sunlig

ht,

wat

er

and m

iner

als;

als

o kn

own a

s a

pro

duce

r or

ganis

m.

ben

chm

ark

a st

andar

d r

efer

ence

poi

nt

use

d in a

st

udy

for

com

par

ison

.bio

accu

mul

atio

n a

pro

cess

wher

eby

toxi

c ch

emic

als

are

conce

ntr

ated

at

succ

essi

vely

hig

her

tro

phic

le

vels

wit

hin

the

food

chai

n.

bio

div

ersi

ty t

he

vari

ety

of s

pec

ies

and t

he

genet

ic

vari

abili

ty a

mon

g in

div

idual

s w

ithin

eac

h s

pec

ies.

bio

me

the

bio

logi

cal co

mpon

ents

of

an e

cosy

stem

.bio

tic

the

orga

nis

ms

that

mak

e up t

he

livin

g par

ts

of e

cosy

stem

s.ca

rniv

ore

a m

eat-

eati

ng

anim

al.

com

mun

ity

a gro

up o

f in

terd

epen

den

t or

ganis

ms

livin

g to

geth

er in a

com

mon

env

iron

men

t an

d

inte

ract

ing

wit

h o

ne

anot

her

.dec

ompos

er a

n o

rgan

ism

that

fee

ds

by

bre

akin

g dow

n t

he

dea

d o

rgan

ic m

atte

r in

an e

cosy

stem

. Exa

mple

s in

clude

bac

teri

a, m

ush

room

s an

d

fungi

. M

ost

chem

ical

s ar

e re

turn

ed t

o th

e so

il an

d

gro

undw

ater

for

reu

se b

y au

totr

ophic

org

anis

ms.

des

erti

fica

tion

the

pro

cess

of

turn

ing

non

-des

ert

lands

into

des

ert

by

poo

r m

anag

emen

t of

the

ecos

yste

m. It

is

usu

ally

cau

sed b

y a

com

bin

atio

n

of o

verg

razi

ng,

soi

l er

osio

n, pro

longe

d d

rough

t an

d

per

hap

s cl

imat

ic c

han

ge.

dyna

mic

equi

libri

um a

sit

uat

ion in w

hic

h s

tabili

ty is

achie

ved in a

n e

cosy

stem

.ec

olog

y th

e st

udy

of o

rgan

ism

s an

d t

hei

r re

lati

onsh

ip t

o on

e an

other

and t

hei

r su

rrou

ndin

gs.

ecos

phe

re t

he

ecos

yste

m o

f th

e pla

net

; th

e to

talit

y of

all

ecos

yste

ms.

ecos

yste

m t

he

dyn

amic

com

ple

x of

pla

nt,

anim

al

and m

icro

-org

anis

m c

omm

unit

ies

and t

hei

r non

-liv

ing

envi

ronm

ent

as a

funct

ional

unit

.ec

oton

e th

e tr

ansi

tion

zon

e w

her

e on

e ty

pe

of

ecos

yste

m b

lends

into

anot

her

. It

usu

ally

con

tain

s m

any

of t

he

pla

nt

and a

nim

al s

pec

ies

found in

bot

h e

cosy

stem

s an

d s

omet

imes

thos

e not

fou

nd

in e

ither

.ex

iste

nce

valu

e th

e am

ount

of m

oney

that

peo

ple

ar

e pre

par

ed t

o sp

end o

r fo

rgo

in o

rder

to

keep

an

eco

syst

em (

or s

pec

ies

wit

hin

an e

cosy

stem

) in

exi

sten

ce.

food

cha

in a

ser

ies

of o

rgan

ism

s, e

ach e

atin

g or

dec

ompos

ing

the

pre

cedin

g on

e.fo

od w

eb a

net

wor

k of

inte

rcon

nec

ted foo

d c

hai

ns.

gene

tic

engi

neer

ing

the

scie

nce

of

man

ipula

ting

the

DN

A o

f or

ganis

ms

to m

odify

orga

nis

ms.

habit

at t

he

envi

ronm

ent

of a

liv

ing

orga

nis

m.

herb

ivor

e an

org

anis

m t

hat

con

sum

es p

lants

as

its

only

sou

rce

of foo

d.

hete

rotr

ophi

c or

gani

sm a

con

sum

er o

rgan

ism

that

is

unab

le t

o m

ake

its

own foo

d.

inte

rdep

enden

ce t

he

dep

enden

ce o

f or

ganis

ms

wit

hin

a h

abit

at o

n e

ach o

ther

for

the

surv

ival

of

thei

r sp

ecie

s.le

achi

ng t

he

rem

oval

, by

wat

er, of

min

eral

s fr

om t

he

upper

lay

ers

of a

soi

l to

the

low

er lay

ers.

mon

ocul

ture

an e

nvir

onm

ent

wher

e on

e pla

nt

spec

ies

dom

inat

es t

otal

ly.

nutr

ient

s el

emen

ts o

r co

mpou

nds

nee

ded

for

the

surv

ival

, gro

wth

and r

epro

duct

ion o

f a

pla

nt

or

anim

al.

omni

vore

an o

rgan

ism

that

con

sum

es b

oth p

lants

an

d a

nim

als

as a

sou

rce

of foo

d.

opti

on v

alue

the

mon

ey t

hat

peo

ple

are

pre

par

ed

to p

ay in o

rder

to

inte

ract

wit

h a

n e

cosy

stem

or

spec

ies.

per

maf

rost

per

man

entl

y fr

ozen

soi

ls; usu

ally

fou

nd

in t

undra

eco

syst

ems.

phy

topla

nkto

n sm

all, d

rift

ing

pla

nts

, m

ostl

y al

gae,

fo

und in a

quat

ic e

cosy

stem

s.pre

dat

or a

n o

rgan

ism

that

cap

ture

s an

d fee

ds

on

anot

her

spec

ies.

pro

duc

er o

rgan

ism

see

auto

trop

hic

org

anis

m.

pro

duc

tivi

ty t

he

rate

at

whic

h b

iolo

gica

l m

atte

r (b

iom

ass)

is

pro

duce

d b

y an

eco

syst

em o

r par

t of

an

eco

syst

em.

spec

ies

all or

ganis

ms

of t

he

sam

e ki

nd t

hat

are

pot

enti

ally

cap

able

of

bre

edin

g an

d p

roduci

ng

fert

ile o

ffsp

ring.

tech

nosp

here

a s

pher

e of

tec

hnol

ogic

al influen

ce,

crea

ted b

y peo

ple

, w

hic

h o

verw

hel

ms

nat

ura

l ec

osys

tem

s.te

rres

tria

l to

do

wit

h t

he

land.

xero

phy

tic

pla

nts

that

exi

st o

n e

xtre

mel

y sm

all

amou

nts

of

wat

er.

zoop

lank

ton

smal

l, f

loat

ing

her

biv

ores

that

fee

d o

n

phyt

opla

nkt

on.

unit

1.1

Eco

syst

ems

at r

isk:

An

Ove

rvie

w

FIGURE 2.6

FIG

UR

E 1

.1.2

Fungi are

an e

xam

ple

of re

cyc

lers

that

ensure

nutr

ients

are

retu

rned t

o a

n e

cosys

tem

.

s

low Precipitation high

bel

ow fre

ezin

g Te

mper

ature

v

ery

hot

Tem

per

ate

rain

fore

st

Subtr

opic

alra

info

rest

Tropic

alra

info

rest

Monso

on

fore

stTe

mper

ate

bro

ad-lea

ved

and m

ixed

fo

rest

Tem

per

ate

scru

b o

r gra

ssla

nd

Tropic

al s

crub

fore

st o

r gra

ssla

nd

Des

ert

Pola

r

Tundra

Nort

her

n

conifer

ous

fore

sts

Cli

mat

e re

gion

s an

d m

ajor

ter

rest

rial

ec

osys

yste

ms

FIGURE 2.6

FIG

UR

E 1

.1.1

Pre

cip

itation a

nd t

em

pera

ture

inte

ract

to d

ete

rmin

e c

hara

cte

ristics o

f ecosys

tem

s.

This

gra

ph d

em

onst

rate

s how

the v

ariabili

ty o

f th

is r

ela

tionship

results in a

wid

e v

ariety

of ecosys

tem

s.

5000 m

m

ge

ojo

bs

Env

iron

men

tal co

nsul

tant

The

requir

emen

t fo

r ec

ologi

cally

sust

ainab

le

dev

elop

men

ts h

as b

ecom

e m

ore

wid

ely

acce

pte

d.

As

a re

sult

, th

ere

is g

row

ing

dem

and f

or c

onsu

ltan

ts t

o as

sist

dev

elop

ers

and g

over

nm

ents

cre

ate

dev

elop

men

ts t

hat

ar

e en

viro

nm

enta

lly f

rien

dly

. Ty

pic

al a

reas

th

ese

consu

ltan

ts w

ork

in a

re:

ad

dre

ssin

g so

il er

osio

n

reco

rdin

g, m

appin

g an

d p

rese

rvin

g nat

ive

flor

a an

d fau

na

dev

elop

ing

stra

tegi

es t

o dea

l w

ith c

limat

e ch

ange

dea

ling

wit

h d

emogra

phic

(pop

ula

tion

) ch

ange

s.

Sev

eral

univ

ersi

ties

now

off

er d

egre

es

spec

ialis

ing

in e

nvir

onm

enta

l co

nsu

ltan

cy.

The e

art

h w

e a

buse a

nd t

he liv

ing t

hin

gs w

e k

ill w

ill,

in t

he e

nd,

take

their r

eve

nge;

for

in e

xplo

itin

g t

heir

pre

sence w

e a

re d

imin

ishin

g o

ur

futu

re.

Mar

ya M

anne

s

Sample

page

s

12G

lobal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

13Eco

syst

ems

at R

isk:

An

Ove

rvie

w

unit

1.1

Nort

hern

coni

fero

us fore

st

Tem

pera

te b

road

-leav

ed a

ndm

ixed fore

st: open

woodla

nd

Tem

pera

te g

rass

land

: so

me

areas

hav

e w

idely

spac

ed t

rees

Tropic

al s

cru

b fore

st

Mons

oon

fore

st

Tropic

al r

ainf

ore

st

Dese

rt

Pola

r (ic

e c

ap)

Tund

ra

Moun

tain

s

Arc

tic C

ircle

Tropic

of C

ancer

Equa

tor

Tropic

of C

apricorn

N

Tropic

al g

rass

land

(sa

vann

a)

Mediterr

anean

typ

e

vegeta

tion

(tem

pera

te s

cru

b)

01

00

02

00

0 k

m

N

Arc

tic C

ircle

Tropic

of C

ancer

Equa

tor

Tropic

of C

apricorn

Gro

nfjö

rden

Pal

erm

oM

osu

l

In S

alah

Colo

mbo

Sin

gap

ore

Dar

win

Har

bin

Belo

Horizo

nte

Chu

rchi

ll

01

00

02

00

0 k

m

Cold

most

mont

hs

with

a sh

ort

sum

mer

Cold

all

year

Clim

ate s

trong

ly a

ffecte

d b

y al

titu

de

Hot

and r

ainy

all

year

Hot

and r

ainy

most

of th

e y

ear

Hot

and m

ost

ly d

ry a

ll ye

ar;

unre

liable

rai

nfal

l

Hot

all y

ear

, ra

iny

most

mont

hsbut

with

a defin

ite d

ry s

eas

on

War

m t

o m

ild s

umm

er,

cool t

o c

old

win

ter,

wet

all y

ear

War

m t

o m

ild s

umm

er,

cool

to c

old

and

dry

win

ter

Hot

and d

ry a

ll ye

ar; un

relia

ble

rai

nfal

l

War

m t

o m

ild m

ont

hs, w

et

all y

ear

War

m t

o m

ild m

ont

hs, dry

in w

inte

r

Hot

dry

sum

mer,

mild

wet

win

ter

FIGURE 2.6

FIG

UR

E 1

.1.7

Worldw

ide c

limatic p

att

ern

s.

TAB

LE 1

.1.1

C

hara

cter

isti

cs o

f m

ajor

ter

rest

rial

eco

syst

ems

Eco

syst

em

Cha

ract

eris

tics

Pol

ar

Per

man

ent

ice

cap,

in p

lace

s up t

o 5 k

m d

eep

N

o pla

nt

gro

wth

; no

anim

al life

away

fro

m c

oast

Tund

raC

over

ed w

ith ice

and s

now

for

much

of

the

year

; per

man

entl

y fr

ozen

subso

il; 1

–3 m

onth

gro

win

g se

ason

Tr

eele

ss;

shru

bby

or m

at-lik

e ve

geta

tion

M

ost

exte

nsi

ve in N

orth

ern H

emis

pher

e

Nor

ther

n co

nife

rous

Lo

ng

win

ters

wit

h a

thic

k co

ver

of s

now

; su

mm

er s

hor

t but

wit

h lon

g, o

ften

war

m,

day

s;

fore

st (

taig

a)

3–4

mon

th g

row

ing

seas

on

Dom

inat

ed b

y co

nifer

tre

es;

thic

k la

yer

of n

eedle

s on

the

gro

und

O

ccurs

on lar

ge c

onti

nen

tal la

nd m

asse

s

Tem

per

ate

gras

slan

d

Err

atic

rai

nfa

ll; f

ires

occ

ur

Dom

inat

ed b

y gra

sses

and a

nnual

s (p

lants

that

com

ple

te t

hei

r lif

e cy

cle

and s

et s

eed

wit

hin

a s

ingl

e gro

win

g se

ason

)

Oft

en e

xplo

ited

for

gra

zing

shee

p a

nd c

attl

e

Tem

per

ate

bro

ad-l

eave

d

War

m,

mild

gro

win

g se

ason

that

var

ies

wit

h lat

itude;

mod

erat

e pre

cipit

atio

n e

venly

an

d m

ixed

for

est

dis

trib

ute

d t

hro

ugh

out

year

; la

rge

seas

onal

diffe

rence

s an

d c

han

ges

in d

ay len

gth;

rich

top

soil

S

ome

tree

s ev

ergre

en,

som

e dec

iduou

s; w

ell-dev

elop

ed u

nder

stor

ey

Med

iter

rane

an-t

ype

vege

tati

onLo

ng,

hot

, dry

sum

mer

s; m

ild w

inte

rs w

ith r

elia

ble

rai

nfa

ll; g

row

th o

ften

sto

ps

in

sum

mer

dro

ugh

tO

pen

for

est

wit

h s

tunte

d t

ree

gro

wth

; w

oodla

nd a

nd s

hru

bla

nd;

man

y bush

es a

nd

shru

bs;

tou

gh e

verg

reen

lea

ves

that

are

oft

en s

pin

yK

now

n a

s ch

apar

ral in

Nor

th A

mer

ica,

mat

orra

l in

Chile

and m

aquis

in t

he

Med

iter

ranea

n a

rea;

als

o fo

und in p

arts

of

south

ern W

este

rn A

ust

ralia

and p

arts

of

Sou

th A

fric

a

Des

ert

Very

lit

tle

rain

; tr

ue

des

ert

has

les

s th

an 1

00 m

m p

reci

pit

atio

n p

er y

ear

and a

rid

area

s le

ss t

han

250 m

m;

hig

h s

um

mer

day

tim

e te

mper

ature

s (o

ften

>37°C

); lar

ge

tem

per

ature

diffe

rence

bet

wee

n d

ay a

nd n

ight

Wid

ely

scat

tere

d s

hru

bs;

wat

er-c

onse

rvin

g pla

nts

and n

on-d

rough

t-ad

apte

d e

phem

eral

s (g

row

and s

et s

eed q

uic

kly

on r

are

occa

sion

s w

hen

wat

er is

avai

lable

); s

ome

very

dry

, sa

ndy

des

erts

hav

e al

mos

t no

pla

nt

gro

wth

G

ener

ally

loc

ated

bet

wee

n 2

and 3

nor

th a

nd s

outh

of

the

Equat

or

Trop

ical

gra

ssla

nd (

sava

nna)

Lo

w r

ainfa

ll but

seas

onal

hea

vy s

torm

s ca

n o

ccur;

fre

quen

t fire

s; t

hin

soi

l

Gra

sses

wit

h s

catt

ered

clu

mps

of t

rees

, gra

din

g in

to e

ither

open

pla

in o

r w

oodla

nd

Trop

ical

scr

ub f

ores

t

Rai

nfa

ll not

abundan

t; h

igh e

vapor

atio

n

Thor

ny s

hru

bs

and t

rees

G

rades

into

tro

pic

al g

rass

land a

nd s

avan

na

Mon

soon

for

est

In

the

trop

ics

but

wit

h d

isti

nct

wet

and d

ry s

easo

ns

Tree

s le

ss c

lose

ly s

pac

ed t

han

in r

ainfo

rest

; m

any

tree

s sh

ed t

hei

r le

aves

in t

he

dry

se

ason

Trop

ical

rai

nfor

est

War

m a

nd h

um

id;

freq

uen

t ra

in;

aver

age

tem

per

ature

is

25°C

all

year

; no

true

seas

ons;

lit

tle

chan

ge in d

ay len

gth;

gro

wth

thro

ugh

out

the

year

; in

fert

ile c

lay

soil

Clo

sed c

anop

y; lit

tle

under

stor

ey;

larg

e num

ber

of

pla

nt

spec

ies

(gre

at d

iver

sity

) co

mpet

ing

for

avai

lable

lig

ht;

tre

es o

ften

hav

e la

rge

trunks

and b

utt

ress

ed r

oots

; m

any

epip

hyt

es (

pla

nts

that

gro

w o

n o

ther

pla

nts

) an

d v

ines

; lit

tle

leaf

lit

ter

Mou

ntai

nIn

crea

sing

alti

tude

pro

duce

s a

dec

reas

e in

tem

per

ature

, si

mila

r to

the

effe

ct o

f in

crea

sing

lati

tude

Vege

tati

on t

ypes

var

y w

ith a

ltit

ude;

bey

ond a

cer

tain

hei

ght,

tre

es d

o not

gro

w a

nd t

he

vege

tati

on r

esem

ble

s tu

ndra

Sou

rce:

Aust

ralia

n A

cadem

y of

Sci

ence

, En

viro

nmen

tal S

cien

ce

FIGURE 2.6

FIG

UR

E 1

.1.6

The w

orld’s

majo

r te

rrest

rial ecosy

stem

s.

Sample

page

s

54G

lobal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

glossary

55

accr

etio

n th

e gro

wth

of

a dune

due

to t

he

build

up

of s

and.

aeol

ian

tran

spor

t th

e m

ovem

ent

of m

ater

ial, s

uch

as

san

d, by

win

d.

bea

ch a

n a

ccum

ula

tion

of

sedim

ent

acti

ng

as t

he

bou

ndar

y bet

wee

n t

he

land a

nd s

ea.

bea

ch n

ouri

shm

ent

the

arti

fici

al r

eple

nis

hm

ent

of

bea

ch s

and.

ber

m t

he

firs

t co

mpon

ent

of t

he

dune

syst

em.

It lie

s cl

oses

t to

the

wat

er’s

edge

and is

crea

ted

by

wav

es p

iling

up s

and. It

is

som

etim

es r

efer

red

to a

s an

inci

pie

nt

dune.

blo

wou

t th

e m

ovem

ent

of s

and inla

nd, of

ten

resu

ltin

g fr

om a

dis

turb

ance

to

the

dune

vege

tati

on.

coas

tal

dun

es e

xpos

ed s

hor

elin

e sy

stem

s of

on

e or

mor

e sa

nd r

idge

s der

ived

fro

m m

ater

ial

tran

spor

ted b

y w

ind a

nd w

aves

.cu

rren

t th

e flow

or

mov

emen

t of

a lar

ge b

ody

of

wat

er in a

n o

cean

. Th

e m

ovem

ent

is c

ause

d b

y pre

vaili

ng

win

ds,

the

eart

h’s

rot

atio

n a

nd t

he

dis

trib

uti

on o

f th

e co

nti

nen

tal la

nd m

asse

s.D

une

Car

e a

com

munit

y bas

ed a

ctio

n g

roup t

hat

ai

ms

to p

rese

rve,

pro

tect

and r

ehab

ilita

te c

oast

al

dune

ecos

yste

ms.

fore

dun

e th

e co

asta

l dune

or lin

e of

dunes

that

is

found b

ehin

d t

he

ber

m. Fo

redunes

are

subje

ct

to e

rosi

on a

nd t

hei

r fo

rm a

nd c

ompos

itio

n a

re

const

antl

y ch

angi

ng.

Als

o kn

own a

s a

fron

tal dune.

long

shor

e dri

ft t

he

mov

emen

t of

sed

imen

t by

curr

ents

runnin

g par

alle

l to

the

shor

e.

mig

rati

ng d

une

a dune

that

is

crea

ted w

hen

a

blo

wou

t is

ext

ended

by

conti

nued

des

truct

ion o

f th

e dune

syst

em. Th

ey m

ove

inla

nd, co

veri

ng

the

landsc

ape

wit

h s

and.

par

abol

ic d

une

a dune

crea

ted b

y blo

wou

ts. Th

ese

are

dunes

that

tak

e on

a ‘U

’ sh

ape

as t

hey

mov

e bac

k th

rough

the

dune

syst

em.

par

alle

l dun

es t

he

lines

of

dunes

that

lie

beh

ind t

he

fore

dune.

They

for

m in lin

es t

hat

run p

aral

lel to

the

bea

ch. A

lso

know

n a

s tr

ansv

erse

dunes

.pre

vail

ing

win

d t

he

mos

t co

mm

on d

irec

tion

fro

m

whic

h t

he

win

d b

low

s in

a g

iven

are

a.sa

ltat

ion

the

tran

spor

tati

on o

f par

ticl

es in a

cu

rren

t of

win

d (

or w

ater

) by

a se

ries

of

bou

nci

ng

mov

emen

ts.

sand

gra

ins

of w

eath

ered

roc

k, s

omet

imes

mix

ed

wit

h c

rush

ed s

hel

l.se

res

each

sta

ge in p

lant

succ

essi

on a

s a

pla

nt

com

munit

y dev

elop

s at

a p

arti

cula

r si

te.

susp

ensi

on p

arti

cles

of

sand c

arri

ed a

long

by

the

win

d, of

ten w

ell ab

ove

the

gro

und.

swal

e a

trou

gh o

r dep

ress

ion t

hat

dev

elop

s bet

wee

n

two

adja

cent

dunes

.w

asho

ut w

ater

was

hin

g ov

er t

he

dune

syst

em f

rom

in

land lak

es a

nd w

ater

cou

rses

. w

ave

a m

ovem

ent

of e

ner

gy

thro

ugh

wat

er c

ause

d

by

the

fric

tion

al d

rag

of w

ind b

low

ing

acro

ss t

he

surf

ace

of a

bod

y of

wat

er. Th

e dev

elop

men

t of

the

wav

e in

volv

es t

he

tran

sfer

of

ener

gy

from

the

win

d

to t

he

wat

er’s

surf

ace.

Wh

at a

re c

oas

tal d

une

s?C

oast

al d

un

es a

re l

arge

acc

umul

atio

ns o

f sa

nd

loc

ated

im

med

iate

ly

behi

nd th

e ac

tive

bea

ch z

one.

The

y ar

e fo

rmed

whe

n sa

nd is

dep

osit

ed

onto

the

shor

e by

wav

e ac

tion

, dri

es o

ut a

nd is

blo

wn

to th

e ba

ck o

f the

b

each

. Thi

s pr

oces

s is

ref

erre

d to

as

accr

etio

n.

On

coas

ts w

here

the

re i

s re

lati

vely

lit

tle

wav

e ac

tion

and

a l

arge

ti

dal

ran

ge,

exte

nsiv

e ar

eas

of t

idal

fl a

ts a

re e

xpos

ed a

t lo

w t

ide.

As

the

tid

e re

trea

ts, t

he s

and

dri

es o

ut a

nd i

s ex

pose

d t

o th

e w

ind

. Ove

r ti

me,

pre

vail

ing

win

ds

shap

e th

e sa

nd i

nto

a sy

stem

of

dun

es.

The

d

une

syst

ems

foun

d a

long

the

Nor

th S

ea c

oast

s of

Den

mar

k, B

elgi

um,

Ger

man

y an

d th

e N

ethe

rlan

ds

wer

e fo

rmed

und

er s

uch

cond

itio

ns.

On

coas

ts w

here

the

tid

al r

ange

is r

elat

ivel

y sm

all,

sand

is d

eliv

ered

to

the

bea

ch b

y w

ave

acti

on. T

he d

unes

for

med

und

er s

uch

cond

itio

ns

rely

mor

e he

avily

on

a co

mbi

nati

on o

f w

ave

and

win

d a

ctio

n. D

une

syst

ems

form

ed u

nder

suc

h co

ndit

ions

are

fou

nd a

long

the

sou

th-e

ast

and

wes

t co

asts

of

Aus

tral

ia, t

he w

est

coas

t of

Afr

ica

and

par

ts o

f th

e ea

st a

nd w

est c

oast

s of

Nor

th A

mer

ica.

In s

ome

part

s of

the

wor

ld,

sand

has

bee

n ac

cum

ulat

ing

sinc

e th

e Pl

eist

ocen

e pe

riod

. T

his

is t

he g

eolo

gica

l pe

riod

dat

ing

from

abo

ut

unit

1.2

Coa

stal

Dun

es

2 m

illio

n ye

ars

ago

to th

e en

d o

f the

last

Ice

Age

, abo

ut 1

0 00

0 ye

ars

ago.

T

hese

anc

ient

san

d d

epos

its

have

, ove

r ti

me,

dev

elop

ed in

to e

norm

ous

dun

efi e

lds

that

hav

e si

gnifi

cant

ly a

lter

ed th

e to

pogr

aphy

of t

he la

nd.

Mas

sive

dun

e fi e

lds,

wit

h d

unes

str

etch

ing

back

man

y ki

lom

etre

s fr

om t

he b

each

, of

ten

dev

elop

in

area

s w

here

ari

d l

and

s ar

e fo

und

ad

jace

nt t

o th

e co

ast.

Des

ert

dun

es,

whi

ch a

re f

orm

ed b

y th

e w

ind

sh

ifti

ng d

ry s

and

s, s

omet

imes

mer

ge w

ith

the

coas

tal d

unes

form

ed b

y th

e la

ndw

ard

mov

emen

t of

bea

ch s

and

s. S

uch

dun

e fi

eld

s ar

e fo

und

al

ong

the

coas

ts b

ord

erin

g th

e Sa

hara

Des

ert i

n N

orth

Afr

ica

and

alo

ng

Wes

tern

Aus

tral

ia’s

nor

ther

n co

astl

ine.

The

se d

unes

can

gro

w t

o va

st

heig

hts

and

can

be

seve

ral k

ilom

etre

s in

leng

th. (

See

fi gu

re 1

.2.1

.)

FIGURE 2.6

FIG

UR

E 1

.2.1

Massiv

e d

une fi e

lds h

ave

deve

loped a

long t

he a

rid

coast

of nort

hern

Weste

rn A

ustr

alia

.

Spat

ial d

istr

ibut

ion

and

dim

ensi

ons

of c

oast

al d

une

ecos

yste

ms

Coa

stal

dun

es a

re fo

und

on

all t

he w

orld

’s c

onti

nent

al la

nd m

asse

s, w

ith

the

exce

ptio

n of

Ant

arct

ica.

The

y fo

rm w

here

ver

ther

e is

san

d a

vaila

ble

for

thei

r co

nstr

ucti

on.

Sand

—gr

ains

of

wea

ther

ed r

ock—

can

be c

lass

ifi ed

as

very

coa

rse

(wit

h a

dia

met

er o

f 1–

2 m

m),

coar

se (

0.6–

1 m

m),

med

ium

(0.

2–0.

6 m

m)

and

ver

y fi n

e (0

.06–

2 m

m).

Win

dbl

own

des

ert s

and

is u

sual

ly fi

ner

than

be

ach

sand

. Bea

ches

gen

eral

ly o

btai

n th

eir

sand

fro

m r

iver

s fl

owin

g to

th

e se

a an

d fr

om th

e w

eari

ng a

way

of c

liffs

.In

som

e co

asta

l ar

eas

othe

r fo

rms

of c

oast

al s

edim

ents

dom

inat

e.

In t

he s

outh

-eas

t of

Eng

land

, for

exa

mpl

e, t

he p

rim

ary

sed

imen

t ty

pe

is s

hing

le.

The

se a

re r

ound

ed,

wat

erw

orn

ston

es,

whi

ch h

ave

been

er

oded

from

the

surr

ound

ing

clif

fs. I

n su

ch c

ircu

mst

ance

s d

unes

do

not

have

the

opp

ortu

nity

to

dev

elop

. T

he s

ourc

e of

coa

stal

sed

imen

ts i

s,

ther

efor

e, v

ery

impo

rtan

t in

det

erm

inin

g w

heth

er s

and

is a

vaila

ble

for

the

cons

truc

tion

of c

oast

al s

and

dun

es.

The

oth

er s

igni

fi can

t fa

ctor

is

win

d. I

t is

the

sin

gle

mos

t im

port

ant

fact

or in

det

erm

inin

g th

e sh

ape

and

ext

ent

of c

oast

al d

unes

. Dun

es a

re

mos

t lik

ely

to d

evel

op in

coa

stal

reg

ions

that

exp

erie

nce

stro

ng o

nsho

re

prev

ailin

g w

ind

s. F

or t

his

reas

on t

he m

ost

exte

nsiv

e d

une

ecos

yste

ms

Of

all

the coast

al

ecosys

tem

s,

sand dunes

have

suff

ere

d th

e gre

ate

st degre

e of

hum

an pre

ssure

. M

any

sand

dunes

have

been

irre

vers

ibly

altere

d

thro

ugh t

he a

ctivi

ties

of

[people

], b

oth

by

accid

ent

and d

esi

gn.

R.W

.B.

Car

ter, c

oast

al g

eom

orphol

ogis

t

ge

ojo

bs

Em

erge

ncy

man

ager

Geo

gra

pher

s st

udy

nat

ura

l haz

ards

and

the

impac

t th

at t

hes

e ca

n h

ave

on t

he

envi

ronm

ent

and c

omm

unit

ies.

Em

erge

ncy

m

anag

ers

are

trai

ned

to

find w

ays

to r

educe

th

e ri

sks

of n

atura

l haz

ards

and t

o pro

tect

co

mm

unit

ies

that

are

in h

azar

d-p

rone

area

s.

The r

eal

confl ic

t of

the b

each i

s n

ot

betw

een s

ea

and s

hore

, fo

r th

ere

is o

nly

a l

ove

r’s q

uarr

el, b

ut

betw

een m

an a

nd n

atu

re.

On t

he b

each,

natu

re h

as

achie

ved a

dyn

am

ic e

quili

brium

that

is a

lien t

o m

an

and h

is s

tatic s

ense o

f equili

brium

.

G.

Sou

cie,

env

iron

men

talis

t

Sample

page

s

58G

lobal

Int

erac

tion

s 2:

Sec

ond E

dit

ion

59C

oast

al D

unes

unit

1.2

Tem

per

atur

eTe

mpe

ratu

re p

lays

an

impo

rtan

t ro

le i

n d

eter

min

ing

the

rate

at

whi

ch

beac

h sa

nd d

ries

and

the

ext

ent

and

typ

e of

veg

etat

ion

that

gro

ws

in

an a

rea.

As

men

tion

ed a

bove

, ve

geta

tion

pla

ys a

n im

port

ant

role

in

det

erm

inin

g th

e ra

te o

f ae

olia

n tr

ansp

ort.

The

tem

pera

ture

als

o af

fect

s th

e fu

ncti

onin

g of

oce

an c

urr

ents

. The

se c

urre

nts

may

hav

e th

e po

tent

ial

to m

ove

sed

imen

t lo

ng d

ista

nces

or

to c

ause

bea

ches

to

be e

rod

ed o

r bu

ilt u

p.

Pre

cipit

atio

nL

evel

s of

pre

cipi

tati

on (

rain

fall)

are

als

o im

port

ant

in d

eter

min

ing

the

natu

re a

nd e

xten

t of

the

veg

etat

ion

bind

ing

the

sand

tog

ethe

r. A

reas

w

ith

regu

lar

rain

fall

are

mor

e lik

ely

to h

ave

a ve

geta

tion

pro

fi le

. Are

as

wit

h lo

w o

r ir

regu

lar

rain

fall

are

likel

y to

rem

ain

unst

able

and

sup

port

lit

tle

vege

tati

on g

row

th.

Hyd

rolo

gica

l pro

cess

esH

ydro

logi

cal p

roce

sses

are

thos

e th

at in

volv

e w

ater

, whi

ch is

one

of t

he

mos

t im

port

ant

agen

ts o

f ch

ange

on

eart

h. A

long

coa

sts

it i

s a

crit

ical

fa

ctor

in

det

erm

inin

g th

e na

ture

of

coas

tlin

es. R

iver

sys

tem

s tr

ansp

ort

sed

imen

t to

the

coa

st,

whe

re i

t is

dis

trib

uted

by

lon

gsh

ore

dri

ft a

nd

ocea

n cu

rren

ts. W

aves

ero

de

clif

fs a

nd h

ead

land

s, p

rovi

din

g ad

dit

iona

l se

dim

ent.

(See

fi gu

re 1

.2.6

.) St

orm

wav

es c

ause

dam

age

to b

each

es, b

ut

cons

truc

tive

wav

es r

ebui

ld th

em.

Win

d-i

nduc

ed

wav

es

play

a

part

icul

arly

im

port

ant

role

in

th

e d

evel

opm

ent o

f coa

stal

dun

es. W

aves

tran

spor

t the

san

d th

at is

nee

ded

fo

r d

une

cons

truc

tion

and

the

y cr

eate

cha

nge

in d

une

syst

ems

by

atta

ckin

g th

em d

urin

g st

orm

s.D

urin

g pe

riod

s of

rel

ativ

ely

calm

wea

ther

, w

aves

bri

ng s

and

fro

m

offs

hore

dep

osit

s (s

uch

as o

ffsh

ore

bars

) an

d d

epos

it i

t on

to b

each

es.

Thi

s sa

nd i

s th

en a

vaila

ble

for

the

win

d t

o tr

ansp

ort

it i

nto

the

dun

e sy

stem

. In

peri

ods

of s

ever

e an

d u

nsta

ble

wea

ther

, sto

rms

crea

te l

arge

an

d p

ower

ful

wav

es t

hat

stri

ke t

he c

oast

wit

h su

ch f

orce

tha

t th

ey

rem

ove

sand

from

bea

ches

and

the

fore

du

ne

area

. In

very

sev

ere

stor

ms

the

wav

es m

ay a

ttac

k th

e d

une

syst

em,

crea

ting

was

hove

rs.

(The

se

even

ts a

re e

xam

ined

in m

ore

det

ail o

n pa

ge X

XX

.)In

ad

dit

ion

to th

e ac

tion

of w

aves

ther

e is

a ra

nge

of o

ther

hyd

rosp

here

-re

late

d p

roce

sses

that

impa

ct o

n co

asta

l dun

es. T

he e

ffec

t of

curr

ents

is

very

impo

rtan

t, pa

rtic

ular

ly th

e pr

oces

s of

lon

gsh

ore

dri

ft.

The

im

port

ance

of

long

shor

e d

rift

lie

s in

its

rol

e as

a t

rans

port

er o

f se

dim

ent.

Sed

imen

t, w

hich

is p

rod

uced

or

dep

osit

ed in

one

par

t of

the

co

asta

l sy

stem

, is

tran

spor

ted

to

othe

r lo

cati

ons

wit

hin

the

syst

em b

y th

e pr

oces

s of

lon

gsho

re d

rift

. Thi

s al

low

s d

unes

and

oth

er s

edim

ent-

base

d l

and

form

s to

dev

elop

in

area

s so

me

dis

tanc

e fr

om t

he s

ourc

e of

co

asta

l sed

imen

ts.

Que

ensl

and

’s F

rase

r Is

land

, a

vast

isl

and

mad

e en

tire

ly o

f sa

nd,

dem

onst

rate

s th

is p

oint

. Som

e of

the

sand

that

mak

es u

p th

e is

land

and

it

s hu

ge d

une

syst

em is

der

ived

fro

m s

and

ston

e d

epos

its

foun

d in

the

Sy

dne

y re

gion

. Lon

gsho

re d

rift

and

oce

an c

urre

nts

have

tran

spor

ted

the

sand

nor

thw

ard

s al

ong

Aus

tral

ia’s

eas

tern

coa

stlin

e.R

ainf

all

is a

noth

er i

mpo

rtan

t fa

ctor

in

the

dev

elop

men

t of

coa

stal

d

unes

. W

hile

rai

nfal

l in

fi ltr

ates

san

d d

unes

wit

h re

lati

ve e

ase,

hea

vy

dow

npou

rs

can

prod

uce

runo

ff,

whi

ch

erod

es

the

sand

y su

rfac

e,

expo

sing

it to

the

win

d. A

noth

er im

port

ant c

hang

e ca

used

by

rain

fall

is

the

dev

elop

men

t of

dun

e la

kes.

The

se la

kes

form

in lo

w-l

ying

are

as o

f th

e d

une

syst

em. F

rase

r Is

land

has

a la

rge

num

ber

of d

une

lake

s.

In t

imes

of

heav

y ra

infa

ll, s

urfa

ce r

unof

f ac

cum

ulat

es i

n a

swal

e,w

hich

is

a tr

ough

or

shal

low

dep

ress

ion

betw

een

the

cres

ts o

f co

asta

l d

unes

. Eve

ntua

lly th

e sa

nd b

ecom

es s

atur

ated

and

the

wat

er ta

ble

rise

s.

Wit

h th

e re

turn

of

war

mer

wea

ther

, the

sw

ale

dri

es o

ut a

nd t

he w

ater

ta

ble

retr

eats

. By

this

tim

e, h

owev

er, m

uch

of t

he p

rote

ctiv

e ve

geta

tion

ha

s d

row

ned

and

the

sand

is n

ow le

ft e

xpos

ed. T

his

caus

es a

mig

rati

ng

du

ne

to fo

rm a

nd b

egin

mov

ing

away

from

the

now

dry

lake

.In

som

e lo

cati

ons,

not

ably

on

Fras

er I

slan

d, d

unes

may

for

m a

cros

s th

e m

outh

of a

val

ley.

If a

str

eam

run

s th

roug

h th

e va

lley,

pon

din

g m

ay

occu

r: t

he d

unes

, act

ing

like

a d

am, h

old

bac

k th

e st

ream

’s w

ater

and

so

a l

ake

is f

orm

ed. S

uch

lake

s te

nd t

o be

sem

iper

man

ent

(or

in s

ome

plac

es p

erm

anen

t) a

nd c

ause

a m

ajor

cha

nge

in t

he lo

cal e

nvir

onm

ent,

enco

urag

ing

dif

fere

nt fl

ora

and

faun

a to

col

onis

e th

e af

fect

ed a

rea.

wo

rkin

g g

eo

gra

ph

ical

ly

+

1D

efin

e an

d e

xpla

in t

he

term

aeo

lian t

ransp

ort.

2O

utli

ne t

he

fact

ors

that

aff

ect

the

rate

of

aeol

ian t

ransp

ort.

1In

terp

reti

ng d

iagr

ams

Exa

min

e figu

re 1

.2.3

. D

escr

ibe

the

rela

tion

ship

bet

wee

n w

ind

velo

city

and t

he

rate

of

aeol

ian t

ransp

ort.

Exp

lain

what

this

indic

ates

abou

t th

e ro

le o

f w

ind in d

une

const

ruct

ion.

2W

riti

ng t

ask

Wri

te a

rep

ort

outl

inin

g th

e ro

le

of w

eath

er in t

he

dev

elop

men

t of

coa

stal

dune

syst

ems.

3W

riti

ng t

ask

Stu

dy

the

Geo

focu

s box

‘Aeo

lian

tran

spor

t’.

aS

tudy

figu

re 1

.2.4

. W

rite

a b

rief

rep

ort

on

the

way

s w

ind t

ransp

orts

san

d.

bW

rite

a p

arag

raph e

xpla

inin

g th

e te

rms

salt

atio

n a

nd c

riti

cal ve

loci

ty.

cD

isti

ngu

ish b

etw

een t

he

pro

cess

es o

f su

rfac

e cr

eep a

nd s

usp

ensi

on.

und

ers

tan

din

g th

e te

xt

FIG

UR

E 2

.6FI

GU

RE

1.2

.6

Much o

f th

e s

edim

ent

used for

dune b

uild

ing c

om

es

from

the e

rosi

on o

f headla

nds

and o

ther

coast

al

featu

res.

ge

ofo

cus

Imp

act o

f Hur

rica

ne

Kat

rin

a o

n th

e

Ch

and

ele

ur Is

lan

ds

i

The

Chan

del

eur

Isla

nds

are

a co

llect

ion o

f lo

w-lyi

ng

isla

nds

off

the

coas

t of

New

Orl

eans,

in t

he

south

ern U

nit

ed S

tate

s.

An e

xten

sive

dune

syst

em is

found o

n t

he

isla

nds

and a

uniq

ue

ecos

yste

m h

ad d

evel

oped

ove

r a

long

per

iod o

f ti

me.

This

par

t of

the

US

coa

stlin

e is

ver

y su

scep

tible

to

hurr

ican

e ac

tivi

ty,

wit

h s

ever

al lar

ge h

urr

ican

es s

trik

ing

the

isla

nds

since

2000:

Hurr

ican

e Li

li (2

002),

Hurr

ican

e Iv

an (

2004)

and H

urr

ican

e D

ennis

(2005).

How

ever

, it

was

H

urr

ican

e K

atri

na

in A

ugu

st 2

005 t

hat

cau

sed t

he

mos

t dam

age

to t

he

dune

syst

em.

Figu

re 1

.2.7

A s

how

the

Chan

del

eur

Isla

nds

in 2

001.

As

can b

e se

en,

a la

rge

dune

syst

em is

loca

ted a

round

the

edge

s of

the

isla

nds.

Fig

ure

1.2

.7B

is

take

n in t

he

day

s fo

llow

ing

Hurr

ican

e K

atri

na.

As

is c

lear

, th

e w

hol

e dune

syst

em h

as b

een d

estr

oyed

by

a m

assi

ve s

torm

sur

ge t

hat

has

engu

lfed

much

of

the

isla

nds.

FIGURE 2.6

FIG

UR

E 1

.2.7

A C

handele

ur

Isla

nds

in 2

001. The e

xtensiv

e d

une s

yste

m is v

isib

le. B

Chandele

ur

Isla

nds

follo

win

g H

urr

icane K

atr

ina in 2

005.

AB

In N

ovem

ber

1970 a

mas

sive

sto

rm s

urg

e an

d

cycl

one

hit

the

coas

t of

India

and B

angl

ades

h

and w

as r

espon

sible

for

as

man

y as

300 0

00

dea

ths.

>

stor

m s

urge

a v

ery

hig

h t

ide

crea

ted b

y a

com

bin

atio

n o

f a

king

tide

(the

hig

hes

t ti

de

in

a ti

dal

cyc

le)

and a

lar

ge s

torm

.

did

yo

u k

now

?!

1

Out

line

the

role

of

hyd

rolo

gica

l pro

cess

es

in t

he

form

atio

n o

f co

asta

l sa

nd d

unes

.2

Exp

lain

the

contr

ibuti

on o

f lo

ngs

hor

e dri

ft

to t

he

dev

elop

men

t of

coa

stal

dunes

.3

Exp

lain

the

pro

cess

es inv

olve

d in t

he

dev

elop

men

t of

dune

lake

s an

d s

wal

es.

4D

efin

e th

e te

rm p

ondin

g. W

hy

is it

so

sign

ific

ant

to t

he

dune

envi

ronm

ent?

und

ers

tan

din

g th

e te

xt

Com

posi

tion

of

sand

sSa

nd i

s no

t un

ifor

m.

Its

chem

ical

and

min

eral

com

posi

tion

var

ies

grea

tly

from

pla

ce t

o pl

ace.

Thi

s is

bec

ause

san

ds

have

bee

n d

eriv

ed

from

dif

fere

nt t

ypes

of

rock

. T

he c

hem

ical

and

min

eral

com

posi

tion

of

san

ds

is v

ery

impo

rtan

t in

det

erm

inin

g th

e na

ture

of

coas

tal

dun

e ec

osys

tem

s.Sam

ple pa

ges