Issues of Scale

• Both time & space

– Time: waves, tides, day, year,

ENSO

– Space: local, regional, global

• Set how processes interact

• Scale invariance

Pacific Coastlin

e

1o latitude =111 km

The Southern California Bight

The Santa Barbara Channel

Scale Invariance

• “Details” appear the same at all scales

• Makes understanding of marine

processes difficult

– always somewhere else to look

• Idea of “fractal” geometry

Time Scales

• Time scales of variability runs from

minutes to decades

• Processes occur on particular scales

Surface waves = minutes

Wind forcing = days

Climate = decadal

Time & Space Scales

• Time & space scales are linked

by the processes driving them

• Large events correspond to long

time scales – T = f(X) (& vice

versa)

– Mass analogy

Time & Space Scales

• Time & space scales are linked

by the processes driving them

• Large events correspond to long

time scales – T = f(X) (& vice

versa)

– Mass analogy

Detail & Time Scale

• The time scale over which

processes are viewed influences

the details observed

• Example – SST in CA Current

A Snapshot of CA Current

• April 1978

• AVHRR - SST

• CZCS Chlorophyll

• Spatial variations on

scales of 5-10 km

SSTChl

Annual Mean SST

Spatial Detail & Time Scale

• The time scale of assessment

influences the “details” observed

Long time averages – large scales only

Instantaneous – both small & large scales

• Time averaging removes small scale

variations – “the moving hand analogy”

Scales for Marine Organisms

• Marine organisms have inherent time &

space scales

– Time: life duration, life cycle, etc.

– Space: foraging, larval dispersion

• Different processes will interact with

marine organisms based upon their

scales

Life Cycles

Life Cycles

Larger is longer…

Larger have more (known) life stages

Larval Dispersion

From Kinlan & Gaines [2003]

Dispersion & Time in Plankton

From Siegel, Kinlan, Gaylord & Gaines [2003]

Plankton Larval Duration (days)

Gen

eti

c D

isp

ers

al Sca

le

(km

)

Scales for Marine Organisms

• The larger the organism the …

longer its life span

more life stages it has

but no real effects on dispersal distance

• Larval dispersal is function of time “in plankton”

• Larger organisms forage & migrate under their own

power & cover larger space scales

• These time scales will interact with physical &

biological time scales of the system

So… can we use this???

•Extended Kelp-Urchin-Otter Food Web

– Add other factors

• Human harvest & regulation, climate, etc.

– Assess time & space scales

– Address management strategies

Otter-Kelp-

Urchin Food Web

Otters are the keystone predator of this food web

Orcas

Otter-Kelp-

Urchin Food Web

Removing otters affects food web structure

OrcasHUMANSAdd Human Harvest

OrcasHUMANS

Other Marine

Mammals

Add Other Mammals

OrcasHUMANS

Other Marine

Mammals

Add Climate Change

Nutrient ’sdue to climate

Substrate ’sdue to climate

OrcasHUMANS

Other Marine

Mammals

Add Oil Spill

Nutrient ’sdue to climate

Substrate ’sdue to climate

What are the time & space scales for this

system?• Forcing of the base of food web is annual &

over large space scales

• Many organisms are long-lived – but may be nearly fixed in space (otters, kelp forests, etc.)

• Climate is ENSO to PDO scales again over large spatial scales

• Oil spills will happen suddenly over variety of space and time scales

OrcasHUMANS

Other Marine

Mammals

Nutrient ’sdue to climate

Substrate ’sdue to climate

BIO

LOG

ICA

L TIM

E

What are the time & space scales for this

system?• Anthropogenic factors follow “legislative time”

– Both harvest policies & marine mammal protection

– Transparency slows management policy changes

• How do fisheries adapt to changing scenarios?

– How do fishermen learn?

– Change in spatial & species targeting

– Build up new markets…

How would you manage this system?

• What do you value?

Fishery income vs. charismatic megafauna vs.

recreational use vs. habitat biodiveristy vs. ???

• Know the interrelationship among causal

factors

• Follow the paths of food energy &

information

– Both are important

Flow

Fish

Settlement

HabitatRecruitment

Harvest

RegulationFisherm

en

Market INFO

Climate

Flow, Fish & Fishing

How would you manage this system?

• Where are the critical juncture points?

– Life history stage vs. keystone species vs. ???

• Play out coupled scenarios

– Most management today is single species

– Not ready for quantitative multi-species

management

– Need assessment of the couplings (even loosely)

• Adapt to change – but anticipate its arrival!!

General Approach

• Focus on connections among

components

– Both food & information

• Know when & over which scale

connections are robust

• Monitor the important causal links

• Adapt to a changing world

General Approach

• Focus on connections among

components

– Both food & information

• Know when & over which scale

connections are robust

• Monitor the important causal links

• Adapt to a changing world