Download Natural Disturbance and Environmental Assessments in

Natural Disturbance and
Environmental Assessments
in the Oil Sands Region
Linda Halsey
April 2012
Why Include Natural Disturbance in
Assessments??
• Driver = JRP Decision
Report for the Joslyn North
Mine (Jan 2011)
• JRP considered it a best
practice for understanding
cumulative effects would
include future fire in the
assessment of change to
terrestrial habitat and
wildlife
• Future fire modeling not
included in EIAs to any
extent prior to JRP
Decision Report
Outline
• Temporal Considerations
• Methods
- Assumptions
- Spatial inclusion of natural disturbance in assessment
- Aspatial inclusion of natural disturbance to generate range
of natural variability
• Results
• Conclusions
Temporal Considerations
• Previous EIAs in the oil
sands assumed static
conditions to forest
structure/age class
• Inclusion of future fire
requires the recognition
that forest structure/age
class is dynamic
– Forest ages
– Fire results in stand
replacement
• Proper and consistent use
of temporal components
critical to the assessment
Temporal Considerations
• Reference Condition
– benchmark(s) for comparison purposes
• Case
– assemblage of developments and activities
• Snapshot
– point in time often defined by a specific Project milestone
Base Case
Baseline Condition
Closure
Application Case
Maximum Build-Out
Stream Diversion
Production Begins
Planned Development Case
Clearing begins
INCREASING DEVELOPMENT
Temporal Considerations
Predevelopment Condition
TIME BASED ON FRONTIER
PROJECT MILESTONES
Temporal Considerations
• Predevelopment Conditions
(No Anthropogenic Disturbance)
• Must include future forest fire to allow for
true comparison of development effects
• Existing Conditions
(Baseline)
• Does not include future forest fire
Temporal Considerations
• Predevelopment conditions were
generated from 2008 data by assigning
vegetation types to all disturbances on
the landscape
• For temporal consistency with
assessment cases predevelopment
vegetation was aged to the appropriate
snapshot (i.e., stands were grown to
reflect the 2057 maximum build-out
snapshot) and natural disturbance (i.e.,
fire) was added and forest age “reset”
to 0 Years
• Existing conditions are at 2008 (not
• Assessment completed
temporally consistent with
relative to
predevelopment and assessment
predevelopment not
cases)
existing conditions
Methods - Assumptions
• 80 year fire cycle (i.e., 1/80th of the
study area burns each year)
• Fire size followed a log normal
distribution (many small fires and few
large fires)
• Forested vegetation cover classes all
had an equivalent potential to burn
(circular fires applied, fires can
overlap)
• Ecosystem succession not considered
(cover classes static with only
structural stage changing for forested
cover classes)
Methods – Spatial Application
• 100 spatial runs completed on the
predevelopment landscape (i.e., no
disturbance) with future fire applied following
the stated assumptions to the Project snapshot
chosen for assessment (i.e., maximum buildout 2057)
• For areas where fire occurred forest age class
was reset to zero and then progressively aged.
For areas where fire did not occur, forest age
class was advanced
• Mean forest age of each spatial run determined
for the study area
Methods – Spatial Application
• Spatial run closest to average mean age of all 100 spatial
runs used in assessment
• Developments than applied to that average mean age
predevelopment landscape by case
Base Case
Application
Case
PDC
Methods – Aspatial Application (RNV)
• Generated RNV for forested cover classes by
considering only natural disturbance (i.e., fire)
• Twenty runs completed using a Monte Carlo simuation
for a 300-year period with the first 100 years being
discarded to ensure decoupling from existing conditions
Coniferous – Jack Pine Leading
140
120
100
80
60
40
20
Average age 81.7 +/- 11.9 years
0
1
51
101
151
201
251
301
Methods – Aspatial Application (RNV)
• Average age for forested cover
class (weighted by landscape
distribution) and the upper and
lower 95% confidence limits of
age were determined
RNV
• Spatial representation of RNV
was generated for the upper
and lower 95% confidence limits
using the 100 natural
disturbance simulations
• RNV used in effects
classification
Predevelopment
Application
Case “A” inside RNV
Application
Case “B” outside RNV
Methods – Additional Considerations
• Inclusion of timber
harvesting for full life of
Project
• Inclusion of progressive
reclamation for regional
developments
Results
• Examples of wildlife
habitat responses to future
fire modeling for several
Species at Risk:
• Canada warbler
(species that prefer
older more structurally
complex areas)
• Wood bison (species
that prefer younger
more open areas)
• Western toad (species
that prefers open
wetlands)
Results – Canada Warbler
• Mixedwood vegetation types that are dominated by
deciduous tree species with a tall (2.5 m to 3.5m), thick
shrubby understory composed of deciduous shrub species
are preferred
• Mature tree stands (structural stages 6 and 7) or greater
than 120 years old are preferred because of higher
abundance of understory as are moist riparian areas and
moist woodlands
• Different disturbance types
lower habitat suitability rankings
within 150 to 300 m of the
disturbance
Results – Canada Warbler
High and Moderate Habitat Availability
(ha)
Change from
Predevelopment
Change Relative
to Range of
Natural Variability
Predevelopment Conditions
170,315
N/A
Existing Conditions
164,217
-3.6% Change within RNV
Base Case
135,386
-20.5% Change within RNV
Application Case
118,609
-30.4%
-6.4%
PDC
117,230
-31.2%
-7.2%
• High and moderate habitat availability consistently drops as
development increases
• Range of natural variability at 5% confidence interval has an area of
129,540 ha or -23.9% of predevelopment
Results – Wood Bison
• High and moderate habitat suitability for wood bison
represented generally by younger forests, shrublands and
grasslands/wetlands that support grasses and sedges
• Different disturbance types lower habitat suitability rankings
within 100 to 200 m of the disturbance
Results – Wood Bison
High and Moderate Habitat Availability
(ha)
Predevelopment Conditions
13,814
Existing Conditions
11,992
Base Case
13,562
Application Case
9,173
PDC
9,173
-13.2% change
-1.8% change
-33.6% change
• Habitat
availability
declines
asmoderate
expected
withavailability
increasing
• Existing
conditions
have less
high and
habitat
than the
assessment
cases due to:
development
Simulated
future fires foras
predevelopment
and assessment
cases
•• RNV
not considered
aspatial simulations
resulted
in
resulting in younger structural stages being present
an
average forest age for relevant cover classes that was
• Inclusion of progressive reclamation and young forests for cases
function ofand
snapshot
beingwith
decoupled
• illogical
Decrease(i.e.,
in fragmentation
Zones ofnot
Influence
addition of
from
minesexisting
for casesconditions)
Results – Western Toad
• All standing and flowing water cover classes (excluding the Athabasca
River), including open fen and marsh vegetation cover class polygons,
were assumed to offer suitable breeding habitat and are therefore
given high ratings.
• Vegetation cover classes with adequate moisture and high ground and
shrub cover were assumed to provide suitable terrestrial habitat.
• Cover classes within 1000 m of breeding habitat had increased habitat
suitability
• Different disturbance types lower habitat suitability rankings within 50
to 400 m of the disturbance
Results – Western Toad
High and Moderate Habitat Availability
(ha)
Change from
Predevelopment
Predevelopment Conditions
756,969
N/A
Existing Conditions
631,763
-16.5%
Base Case
635,916
-16.0%
Application Case
605,275
-20.0%
PDC
572,386
-24.4%
• Slight increase between existing conditions and base case reflects
progressive reclamation and increase in areas of open water
• No change in habitat rankings associated with fire as open and
shrubby wetlands static (i.e., range of natural variability not included)
Conclusions
• Frontier Oil Sands Mine first assessment to include natural disturbance
as part of cumulative effects assessment for terrestrial habitat and
wildlife species
• Clear need to ensure proper use of temporal conditions
• Old growth dependent species results are logical
• Young forest dependent species results not inherently logical
• Limitations:
• Only of relevance to species that have a high dependency on
habitat types related to forest age class
• Spatial inclusion of fire highly dependent on existing conditions and
length of snapshot time
• Acknowledgements: Teck Resources Limited, Owner and Applicant of
the Frontier Oil Sands Mine Project