No Slide Title - wilderness.net€¦ · California butterflies are flying earlier. Ranked date of...

WildernessChallenged:The new era ofunprecedented andunpredictable globalchanges

Nathan L. Stephenson

U.S. Department of the InteriorU.S. Geological Survey

1. Climate change and its effects are here.A. It’s getting warmer.B. Effects of climate change are already evident.C. Profound changes are expected for the future.

2. In the face of unprecedented global changes, pastconditions no longer automatically provide us withsensible management targets for the future.A. Future conditions will have no analog in the past.B. The problem with “back to the future.”

3. The future is uncertain, forcing us to think and act infundamentally new (revolutionary!) ways.A. We cannot predict the future in detail.B. In spite of uncertainty, we can still plan and act.C. Rethinking the meaning of “natural.”D. Taking action 1: Adapting to climatic change.E. Taking action 2: Mitigating climatic change.




Recent temperatures are the warmest sincegood instrumental records began in the 1880s

Proxy records (e.g., from tree rings, corals, cave formations)show that recent temperatures are almost certainly the

warmest of the last 1,700 years

Mann et al., PNAS, 2008

Current atmospheric CO2 concentrations arethe highest in at least the last 650,000 years,

and probably in the last 20 million years.

The longer view: CO2 concentrations

Years before present

Atm

osph

eric

CO

2 con

cent

ratio

n(p

arts

per

mill

ion)

0

100

200

300

400

600,000 300,000 0

Today!




Photo by G. K. Gilbert

(1) Glaciersare melting

August 14, 1908

Photo by H. Basagic

August 2, 2003

Darwin glacier,Kings CanyonNational Park,Sierra Nevada

US Forest Service lands

National Park Service lands

Glaciers and ice features

Andrew G. FountainPortland State Univ.

Stewart et al., J. Climate, 2004

(2) Summers are getting longer and drier:Snow fall is declining (relative to rain):

Snowpack water content is declining:

Spring snowmelt is arriving earlier:

Mote et al., BAMS, 2005

Knowles et al., J. Climate, 2006

Stewart et al., J. Climate, 2004

(2) Summers are getting longer and drier:Snow fall is declining (relative to rain):

Snowpack water content is declining:

Spring streamflow is arriving earlier:

Mote et al., BAMS, 2005

Knowles et al., J. Climate, 2006

(3) Area burned is increasing, fire season is lengthening, and fires are harder to control ...

Photo: N. Stephenson

(From Arno 1996, updated by Caprio 2002)

Year1920 1930 1940 1950 1960 1970 1980 1990 2000

0

1

2

3

4

5

6

Acres Burned - 1916 to 2002

Burn

ed a

rea

(milli

ons

of a

cres

)

Western states (bars) and California (line)

Westerling et al., Science, 2006

... at least partly due to warming.

(4) Animals are on the moveThe Grinnell Resurvey Project, Sierra Nevada1914 - 1920 2003 - 2006

Bancroft Library, UC Berkeley

© Les Chow

MVZ, UC Berkeley

Elev

atio

n (m

eter

s)

Species

Moritz et al., Science 2008

Small mammals are moving upslope in the Sierra Nevada.

(5) Phenology is changingCalifornia butterflies are flying earlier

Ran

ked

date

of f

irst f

light

Forister & Shapiro 2003, Glob. Change Biol.

(6) “Background” tree mortality ratehas more than doubled across the West …

Photo: N. Stephenson

1960 1970 1980 1990 2000

Year

Mor

talit

y ra

te (%

yr-1

)

van Mantgem et al. 2009van Mantgem & Stephenson 2007

… most likely due to warming.

IPCC 2007

You are here.

IT’S GOING TO GET A LOT WARMER!




Climatic extremes will likely become more frequentand more extreme

Mountain snowpack will diminish significantly,lengthening the summer drought

Knowles & Cayan 2004, Clim. Change

Fire season will lengthen

Credit: USFS

FormerreserveReserve

Rangelimit

Speciesrange

FutureWilderness

Potentialrange limit

Formerrange limit

After Peters (1992)

Species’ ranges will shiftMany current protected areas will become unsuitable

Formerreserve

Rangelimit

Speciesrange


Formerrange limit

After Peters (1992)

Wilderness


FutureWilderness

Wilderness

Rangelimit

Speciesrange


Formerrange limit

After Peters (1992)

Wilderness


FutureWilderness

Can mountain protected areas save the day?

A

B

C

After Peters (1992)

A

B

C

B

C

D

After Peters (1992)

If only the temperaturechanges ...

Enoughsoil for B?

Only sometimes.

Making it real for giant sequoias, ~100 to 150 years from now:

Can this ... ... become establishedand thrive here?

A

B

C

E

F

G

After Peters (1992)

A more likely scenario ...

If precipitation timingand amount also

change ...

Species’ ranges will shiftSpecies will behave individualistically, meaning

it will be impossible to maintain biotic communitiesin their current or “natural” state.




The 800-pound gorillas:

(1) Altered disturbance regimes

Even without climatic changes, protected areasare already faced with a suite of novel stressors.

Goal: ~10,000 ha per year

Accomplished:~1,500 haper year(15% of goal)

After 40 years, we haven’t come close to restoring fire regimes at a landscape scale.



(2) Pollution

• Acid deposition• Nitrogen deposition• Pesticides• Particulates• Ozone• CO2

Photo credits: NPS

N deposition, 1860 N deposition, 1993

500020001000750500250100

50255

Galloway & Cowling 2002;Galloway et al., 2002b

Humans now fix more biologically active nitrogen per yearthan is fixed by natural processes.

Western Airborne Contaminants Assessment Project (WACAP)



(2) Pollution

(3) Non-native invasive species

• Animals• Plants• Pathogens

Credit: Todd Esque, USGS

An example from the Mojave desert:

Invasion altered fire regime loss of natives



(2) Pollution


(4) Habitat fragmentation

• Reduced gene flow• Disrupted metapopulation dynamics• Habitats too small for viable populations• Barriers to species reintroductions and

migrations

The 800-ton gorilla:


(2) Air pollution



(5) Rapid climatic change

2100:Moderate-emissions

scenario

2100:High-

emissionsscenario

Red = environments that disappear from U.S.Orange = environments that decrease in U.S.Green = environments that increase in U.S.

Saxon et al. 2005, Ecol. Lett.

Climatic changes will cause many contemporaryenvironments to disappear ...

Saxon et al. 2005, Ecol. Lett.

White = environments with a current analog in U.S.Gray = environments without current analog in U.S.,

under both emissions scenariosBlack = environments without current analog in U.S.,

under high emissions scenario

... and no-analog (novel) environments to appear.

2100

- Altered disturbance regimes- Pollution (N deposition, O3, etc)

- Non-native invasive species- Habitat fragmentation

EVERY ENV’T MAY BE A NO-ANALOG ENV’TSaxon et al. 2005, Ecol. Lett.

White = environments with a current analog in U.S.Gray = environments without current analog in U.S.,

under both emissions scenariosBlack = environments without current analog in U.S.,

under high emissions scenario

... and no-analog (novel) environments to appear.




I like managing

ecosystems!

Uh oh! Rough water. … Let me put things back the way they were! *

* … or let me sit backand watch natural processessort things out on their own!

Honest, I can hold it

all together!

There goes my

promotion.

An example of a threshold response:The massive piñon pine die-off in the Southwest

Credit: Craig Allen & NSF

The drought was not exceptional (it was wetter than the1950s drought), but the temperature was higher

Annu

al p

reci

pita

tion

(mm

) Annual temperature (˚C

)

YearBreshears et al. 2005, PNAS




The important distinctions amongpredictions, forecasts, and scenarios.

PREDICTION: projecting a future state by usingan empirically validated model that’s usuallybased on well-established first principles(these models are often called “laws”).

e.g., from Chemistry 101, the Ideal Gas Law:

PV = nRT

FORECAST: projecting a future state by usinga model that may be incomplete, weaklyvalidated, not based on well-established firstprinciples, or otherwise known or suspectedto be significantly imperfect.

For example …

IPCC 2007

Forecasts of future climatic changes depend heavily on:(1) presumed future greenhouse gas emissions,(2) the particular global climate model used, and

(3) the scale of interest (e.g. global vs. regional vs. local).

For example, we don’t know if northern California will get warmer and wetter or warmer and drier!

Dettinger 2005

Bachelet et al. 2003, Global Biogeochem. Cycles

Uncertainty in future conditions is further compoundedby uncertainty in biotic models.

MC1model

LPJmodel

SCENARIO: a plausible and internally consistent“story” about a possible future.

For example:“In 2050 the Sierra Nevada is warmer and

wetter, but snow is melting much earlier; wildfires are somewhat larger and harder to control; and an emergent pathogen is killing giant sequoias at 20 times the ‘normal’ rate.”

SCENARIO: a plausible and internally consistent“story” about a possible future.

For example:“In 2050 the Sierra Nevada is warmer and

wetter, but snow is melting much earlier; wildfires are somewhat larger and harder to control; and an emergent pathogen is killing giant sequoias at 20 times the ‘normal’ rate.”

• Forecasts are foundational to scenarios.• Future policy and management decisions will

depend heavily on arrays of scenarios.



(2) Pollution



Uncertainty will be compounded even further by interactions between climatic changes and other agents of change …

Credit: Roland Knapp

Credit: Vance Vredenburg et al.

... and we’re bound to be blindsided by completelyunanticipated events (e.g., the devastating rise of chytrid).

Bottom line: Surprises are inevitable!




CONTROLLABLE UNCONTROLLABLE

LOW

HIG

H

Unc

erta

inty

Controllability

Adaptivemanagement

Optimalcontrol

after Peterson et al. 2003, Conserv. Biol.

CONTROLLABLE UNCONTROLLABLE

LOW

HIG

H

Unc

erta

inty

Controllability

Adaptivemanagement

Scenarioplanning

Optimalcontrol

Hedging

after Peterson et al. 2003, Conserv. Biol.

Scenario PlanningWhat is it?

• A tool for long-term strategic planning, when the future is both uncertain and uncontrollable.

Scenarios Are:

• Compelling narratives (stories) of alternative futures in which decisions may be played out.

• Coherent, internally consistent, and plausible.

Courtesy of Leigh Welling, NPS

Scenario PlanningWhat is it NOT?

• A method for arriving at the “most likely” future.

Scenarios Are Not:

• Predictions

• Forecasts

• Strategies


One Dimensional vs. Scenario Planning

One-Dimensional Planning

Outcomes

BA

CD

Scenario Planning

BA

CD

Possible Futures

ElementsCommon to A-BElements

Common to A-CElementsCommon to A-D


One Dimensional vs. Scenario Planning

One-Dimensional Planning

Outcomes

BA

CD

Scenario Planning

BA

CD

Possible Futures

ElementsCommon to A-BElements

Common to A-CElementsCommon to A-D


A ridiculously simple example of scenario planning

Possibleadaptations

to scenario #1:a warmer,

wetter future.


Possibleadaptations


wetter future.

Possibleadaptations


drier future.


Possibleadaptations


wetter future.

Possibleadaptations


drier future.

Consider implementing adaptation strategies that fall

in this zone.

We will need to drop the well-entrenched tradition ofdefining desired future conditions in terms ofprecise targets or ranges of targets (often basedon “natural range of variability” or “historical rangeof variability”)

Instead, we may need to define UNdesired futureconditions – those to avoid (e.g., extinctions;sudden loss of vegetation cover followed bymassive erosion).

Other implications for how we plan:

We will need to drop the well-entrenched tradition ofdefining desired future conditions in terms ofprecise targets or ranges of targets (often basedon “natural range of variability” or “historical rangeof variability”)

Instead, we may need to define UNdesired futureconditions – those to avoid (e.g., extinctions;sudden loss of vegetation cover followed bymassive erosion).

Avoiding undesired future conditions often will meanwe manage for ecosystem resistance andresilience to stresses.

Other implications for how we plan:

Resistance: ability to resist stresses.Resilience: ability to recover from stresses.

Rough water.But rather than

mimic the past, I shall begin to

ADAPT by enhancing

resistance and resilience!




The National Park Service’sManagement Policies usesthe word “natural” 566 times,averaging more than 3 timesper page …

So we can still plan … but for WHAT?


… but with climatic change andother global changes, is “natural” dead?



… but with climatic change andother global changes, is “natural” dead?

No, but we need to be muchmore careful and deliberateabout how we think about it.


David ParsonsJohn Randall Nate Stephenson Kathy TonnessenPeter WhiteStephen WoodleyLaurie YungErika Zavaleta

Greg ApletF. Stuart ChapinDavid ColeDavid GraberEric HiggsRichard HobbsPeter LandresConnie Millar

… with thanks to the “Beyond Naturalness” group:

The three axes of “naturalness”

Historical fidelity (e.g., NPS’s “vignettes ofprimitive America” and“historical range ofvariability.”)

High

Low

What is “natural?”

Historical fidelity

Freedom fromintentional

human control

High

Low

(e.g., the Wilderness Act’s “untrammeled”)


Historical fidelity


human control

High

Low

Freedom fromunintended

human influences (such as pollution, invasives, global warming)


Historical fidelity


human controlFreedom fromunintended


“Natural” by allthree metrics

High

Low

High

Low

High

Low


Historical fidelity




“Unnatural” by allthree metrics

High

Low

High

Low

High

Low




human influences

Low

In the face of rapid global changes, protected areasmanagers are forced into tradeoffs on a “surface of the possible”

Historical fidelity

(such as pollution, invasives, global warming)

High

High



human influences

Low

Historical fidelity


Favoring “vignettesof primitive America”over “untrammeled”

High

High



human influences

Low

Historical fidelity


High

High

Favoring “untrammeled”over “vignettes ofprimitive America”



human influences

Low

Historical fidelity


High

High

As unintended human influences (global changes) come todominate, the range of available tradeoffs keeps shrinking …



human influences

Low

Historical fidelity


High

High

… and ecosystem inertia, or management efforts to maintain highhistorical fidelity, could lead to inherently unstable conditions ...

Inherently unstable …at risk of sudden,

catastrophic change.

Stable



human influences

Low

Historical fidelity


High

High

Inherently unstable …at risk of sudden,

catastrophic change.

Stable

… with the corollary that efforts to maintain biotic communitieswith high historical fidelity will eventually become futile.

(1) Protected areas managers will be forced to chooseamong tradeoffs, choosing to emphasize one aspect(axis) of naturalness over another.

(2) Ecosystem inertia in a rapidly-changing environmentcould lead to unstable conditions and the sudden, catastrophic loss of some of the very values we soughtto preserve.

(3) Trying to maintain conditions beyond their new bounds of stability could lead to the sudden, catastrophic loss of some of the very values we sought to preserve.

(4) Efforts to maintain “natural” (historical) bioticcommunities will likely become counterproductive, if notimpossible.

Summary: Consequences of rapidglobal changes to “naturalness”




Step 1: redefining goals for Wilderness.

a. “Let it be,” and knowingly accept theconsequences. By default, this approachmay dominate large areas.



human influences

Low

Historical fidelity


High

High

The reality of managing huge landscapes is thatlarge areas may receive little intentional human intervention.

Step 1: redefining goals for Wilderness.

a. “Let it be,” and knowingly accept theconsequences. By default, this approachmay dominate large areas.

b. In strategically chosen areas, actively manage to maintain regional native biodiversity and key ecosystem functions.

To accomplish the latter, we may haveto start doing things that currently

would make us cringe.(I don’t necessary advocate what follows …

I’m just trying to provoke discussion.)

Giant sequoia

Joshua tree

(1) Decide how you’ll treat displaced natives.

Probably won’t goextinct (though may

still suffer).CONTINGENCY PLAN:Monitor, and continuemanaging bear-human

interactions.But I’m from the government, and I’m here to help.

(2) Create triage lists, with possible actions.

May be in bigtrouble without

our help.CONTINGENCY PLANS:

(1) assisted migrationupslope,

(2) drip irrigation inselected areas.

Courtesy of Scott Anderson, NAU

Doomed,at least within

the park or region.CONTINGENCY PLANS:

(1) identify northern mountainparks willing to accept this

displaced native, or(2) leave it to fend for itself,and consciously accept the

consequences.

... but I’m so

CUTE!

Examples of reconsidering the pariahs:Assisted species migrations?

(3) Reconsider the pariahs.

Credit: Quincy Library Group

Examples of reconsidering the pariahs:Purposely over-thin forests to increase

resistance and resilience?

+

=Florida Panther Mountain Lion

Improved adaptive potential in the face of an uncertain future?

Examples of reconsidering the pariahs:Mix gene pools to increase adaptive potential?

Examples of reconsidering the pariahs:Weather modification?




Mitigation: How can we slow climatic changes?

Managers of federal lands and waters may soon be held accountable for their ecosystems’ carbon (C) balances. The result is likely to be attempts to use ecosystems as giant sponges to sop up CO2.

Mitigation: How can we slow climatic changes?

Managers of federal lands and waters may soon be held accountable for their ecosystems’ carbon (C) balances. The result is likely to be attempts to use ecosystems as giant sponges to sop up CO2.

But rather than focusing on increasing C sequestration, in many cases we more realistically need to focus on reducing losses of C that is already sequestered.

1960 1970 1980 1990 2000

Year

Mor

talit

y ra

te (%

yr-1

)

van Mantgem et al. 2009

Are we already losing C in “pristine” old-growth forests?

LOST after a prescribed fire:About one third of live bole biomass

Hurteau et al. 2008, Front. Ecol. Env.

GAINED after a prescribed fire:Increased resistance to sudden loss of the

remaining biomass.

1. Climate change and its effects are here.

2. In the face of unprecedented global changes, pastconditions no longer automatically provide us withsensible management targets for the future.

3. The future is uncertain, forcing us to think and act infundamentally new (revolutionary!) ways.

SUMMARY:

Thank you for your time!

Date post:	18-Aug-2018
Category:	Documents
Upload:	truongdieu
View:	216 times
Download:	0 times

No Slide Title - wilderness.net€¦ · California butterflies are flying earlier. Ranked date of...

Documents