21daveandison

Alternative Perspectives on Rehabilitating Post-Beetle Landscapes

MTT FRI MPB IEF

April 24, 2014

Edmonton, Alberta

Dr. David Andison

Healthy Landscapes Healthy Landscapes

Program

Overview

Rehabilitation: “…seeks to repair damaged or blocked

ecosystem functions with the primary goal of raising

ecosystem productivity for the benefit of local people.”

Aronson et al. (1993)





Restoration: “…the intentional alternation… to

establish a defined indigenous, historic ecosystem…to

emulate the structure, function, diversity, and dynamics of

the specified ecosystem”

US Society for Ecological Restoration





Reallocation: “ when part of a landscape is assigned a

new use that does not necessarily bear an intrinsic

relationship with the pre-disturbance ecosystem..”

Aronson et al. 1993










Reallocation: “ when part of a landscape is assigned a

new use that does not necessarily bear an intrinsic

relationship with the pre-disturbance ecosystem..”

Aronson et al. 1993






Ecological “Degradation”

Restoration

Rehabilitation

Reallocation

Low High

BAU

Management

Response

Threshold of

Irreversibility

“Irreversible Thresholds”

• A point beyond which the system cannot go back to its

previous state without intervention. A new “state” is

realized.

• Once pushed beyond these natural limits, a system will

re-assemble itself into a different & lower-order entity.

Ecosystem

Condition(s) Ecosystem

Condition(s)

High resilience &

Low stability

Low resilience &

High stability

(NRV)

Resilience is the capacity of a system to return to a

former trajectory after degradation (sic change).

Resilience is the ultimate measure of ecosystem health.

Vital Ecosystem Attributes as indicators of ecosystem structure

and function (my additions in brackets)

Structure

• species richness (& evenness)

• (habitat diversity)

• (vertical diversity)

• keystone species

• microbial biomass

• soil biota diversity

Function

• biomass productivity

• soil organic matter

• max soil water reserves

• rain use efficiency

• N efficiency

Resilience is difficult to measure since it relates to

function and structure.

How Degraded was the System Before MPB?

??

How Degraded Was the System

Before MPB? • Harvesting

• 2,700 ha / 100,000 ha / decade NE Alta (370 yr cycle)

• 6,500 ha / 100,000 ha / decade Foothills (165 yr cycle)

• Low duration, moderate severity

• Small energy (<10 ha) • Account for <3% by area

• 85% by density in NE Alta – 1 site every 510 ha

• 70% by density in Foothills – 1 site every 284 ha

• High duration, high severity

• Large energy installations (>10 ha) • No data on specifics wrt area and density

• Very high duration, very high severity

• Linear features • 0-7 km / km2 in NE Alta (Latham et al. 2011)

• 0-4 in Foothills (DeCesare et al. 2012)

• High duration, high severity

• Fire control

1. Severity

2. Frequency

How Degraded Was the System

Before MPB?

Total Remnants for all Events > 5 Ha.

0

5

10

15

20

25

30

35

40

>0-10

>10-20

>20-30

>30-40

>40-50

>50-60

>60-70

>70-80

>80-90

>90-100

Proportion of Event in Remnants

Rela

tive F

req

uen

cy Hot Fires Cool Fires

• 25% of the time remnants 11-27% by area



Percent of Area Within Historic Wildfires

That Survives

Percent of Wildfire Area that Survives

0

5

10

15

20

25

30

35

40


Re

lati

ve

Fre

qu

en

cy

Percent of Wildfire Area that Survives

0

5

10

15

20

25

30

35

40


Re

lati

ve

Fre

qu

en

cy

Fire Control Effectiveness

Hot fires Cool fires

Hard to control Easy to control

0-20 years

20-50 years

>100 years

50-100 years

A

B

C

D

Classic boreal forest

dynamics theory

On average, every 60-100 years

Young simple stand

Immature simple stand

Mature simple stand

Young simple stand


Mature simple stand

Old stand

Total Remnants for all Events > 5 Ha.

0

5

10

15

20

25

30

35

40

>0-10

>10-20

>20-30

>30-40

>40-50

>50-60

>60-70

>70-80

>80-90

>90-100


Rela

tive F

req

uen

cy Hot Fires Cool Fires

Percent of Area Within Historic Wildfires

That Survives

0-20 years

20-50 years

>100 years

50-100 years

A

B

C

D

Z

Y

X

Hot Fires Cool Fires

Historically, the

boreal had some

of both

Young simple stand


Mature simple stand

Mature complex stand

Young complex stand

Young simple stand

Immature complex stand


Mature simple stand

Old stand

Historical Perception Historical Reality

Young simple stand


Mature simple stand

Mature complex stand

Young complex stand

Young simple stand

Immature complex stand


Mature simple stand

Old stand

• Vertical diversity

• Habitat diversity

• Species richness

• Soil biota

Historical Reality Current condition?

• Fire control is creating lots of classic “old” forest

“Prevention of natural disturbance through aggressive fire suppressionn…, has

resulted in forests that are much different (i.e., older) than would have

occurred naturally if fires had been allowed to run their course. Compared to

younger, open-canopy habitats, older forests typically do not provide as much

food (berries and forbs) for grizzly bear”.

Alberta Grizzly Bear Recovery Plan (2008)

How Degraded was the System Before MPB?

?? ??

Historical Possibilities of Ecosystem

Conditions

• Vegetation species

• Age(s)

• Density

• Height(s)

• Patch sizes

• Seral levels

• Str. complexity

• Comp. Complexity

• Edge density

• Peak water flows

• …

Current Possibilities of Ecosystem

Conditions

Fire control

Roads /

Hwys

Seismic

lines

Well

Sites

Pipelines

Future

MPB

impacts?

Urbanization

Etc..

Three questions:

1. What is the problem to be solved?

• “Fix” MPB “damage” or ecosystem health?

• Manage pieces or wholes?

• The human element

• Yellowstone example

2. What Historical Reference Point(s) Are We Using?

??

3. Could this become an opportunity?

Date post:	25-Mar-2016
Category:	Documents
Upload:	fri-research
View:	214 times
Download:	0 times

21daveandison

Documents