Cumulative access in Canada’s forest ecozones
By: Peter Lee, Matthew Hanneman, Jeannette Gysbers, and Ryan Cheng
This is the second of several publicatons in celebration of Global Forest Watch Canada’s 10th anniversay year
and in celebration of the International Year of Biodiversity. It summarizes the results of several years of mapping anthropogenic disturbances as seen by Landsat satellite imagery.
This bulletin accompanies Global Forest Watch Canada’s (GFWC) geospatial dataset (Canada Access – Combined) and high resolution maps in PNG, TIFF and JPEG formats which are available at http://www.globalforestwatch.ca/datawarehouse/datawarehouse.htm and http://www.globalforestwatch.ca, respectively.
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What is Cumulative Access?
How was the Cumulative Access
dataset created?
Cumulative access is the combined land surface anthropogenic disturbances caused mainly by industrial activities, which include, but are not limited to, roads, mines,
clearcuts, wellsites, pipelines, transmission lines, and
agricultural clearings.
GFWC’s Cumulative Access dataset is a by-product of
our work on another GFWC project, Canada’s Intact Forest Landscapes.
In order to map Canada’s intact forest landscapes,
GFWC first mapped all anthropogenic disturbances as
Global Forest Watch Canada (GFWC) has analyzed the
already mapped in readily available and reliable existing
extent to which Canada’s forest ecozones have been
datasets (especially roads datasets) and as seen on Landimpacted by significant human activities. GFWC’s cumu- sat images. All resulting features were mapped as either
lative access layer was compiled primarily by analyzing
linear or polygon features. Then, using Geographic InLandsat (TM and ETM) satellite images for the period
formation Systems software, GFWC applied buffers to
1988 to 2006.
these disturbance datasets. A zone of influence of 500
metres was applied to local roads (i.e. subdivision roads
in a city or gravel roads in rural areas), airports, mines,
pipelines, powerlines, reservoirs, and clearcuts. A zone
________________________________________________________________________________________
Citation: Lee PG, Hanneman M, Gysbers JD, Cheng R. 2010. Cumulative access in Canada’s forest ecozones. Edmonton,
Alberta: Global Forest Watch Canada 10th Anniversary Publication #2. 7 pp. Available at: www.globalforestwatch.ca.
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of influence of 1,000 metres was applied to the TransCanada Highway and other principal roads. The width
of the zone of influence was considered conservative,
given that many studies have shown that the effects
of disturbance greatly exceed 1,000 metres for birds,
predators, and ungulates, as well as smaller wildlife. For
example, one Ontario government study on wildlife
areas used 5- and 10-kilometre buffers. Applying these
buffers also helped to mask errors related to orthorectification problems with Landsat satellite imagery.
Although this Cumulative Access dataset was not specifically developed as a stand-alone dataset, GFWC is
making it available due to increasing requests by government agencies and academics and due to its apparent usefulness for some kinds of analysis (e.g., see: A.
Schindler, D.W. Comprehensive conservation planning to protect
biodiversity and ecosystem services in Canadian boreal regions under a warming climate and increasing exploitation. Biol. Conserv.
(2010), doi:10.1016/j.biocon.2010.04.003; B. Environment
Canada. 2008. Scientific Review for the Identification of Critical Habitat for Woodland Caribou (Rangifer tarandus caribou),
Boreal Population, in Canada. August 2008. Ottawa: Environment Canada. 72 pp. plus 180 pp Appendices.)
The resulting layers of buffered features were combined
to create an anthropogenic disturbance layer. These
areas were then removed from further consideration
as intact forest landscapes. Additionally, residual areas
smaller than 5,000 hectares for the boreal/taiga ecozones and smaller than 1,000 hectares for the temperate
forest ecozones were removed according to the threshold sizes selected.
What are some of the limitations of
the Cumulative Access dataset?
GFWC recommends that users of the dataset become
familiar with its creation and resulting limitations for
various desired uses. GFWC notes that there are several
limitations, including:
•
The anthropogenic disturbances were
mapped from Landsat images of a variety of dates,
although the general period of consistency is in the
1999-2002 range.
•
Landsat images are considered to be medium
resolution, therefore fine-scale anthropogenic disturbances were not detected and mapped.
•
The 1,000 metre (for primary highways)
and 500 metre (for all other anthropogenic disturbances) buffering that was applied to all linear and
polygonal features results in a coarse-level dataset
that may not be appropriate for some analysis.
•
Areas shown as having no cumulative access and that are smaller than 5,000 ha for the
boreal/taiga ecozones and smaller than 1,000 ha
for temperate forest ecozones may in fact contain
cumulative access. These smaller areas may have
been missed in the mapping as they were not the
focus of the original intact forest landscape mapping project.
Further details of the methodology are contained within
GFWC’s publication: Lee P, JD Gysbers, and Stanojevic Z.
2006. Canada’s Forest Landscape Fragments: A First Approximation (A Global Forest Watch Canada Report). Edmonton,
Alberta: Global Forest Watch Canada. 97 pp. (Available at:
http://www.globalforestwatch.ca/FLFs/download.htm).
Why is GFWC making this by-product dataset available?
GFWC’s policy is to make geospatial datasets readily and
publicly available, and where reasonable, free-of-charge.
Reasons for this policy include:
•
To encourage others, particularly in governments and industry, to do the same.
•
To be transparent and to enhance credibility
of GFWC products by allowing others to use and
comment on our datasets.
•
To encourage others to conduct additional
and new analysis, using GFWC’s datasets, in order
to improve Canada’s sustainable forest management
decisions.
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Maps of Cumulative Access
British Columbia, Ontario and Québec – contain almost
77% of Canada’s accessed forest ecozone area.
The map, Cumulative Anthropogenic Access in Canada’s Forest
Ecozones, provides a national picture of the cumulative extent of industrial access within Canada’s forest
ecozones. The map, Watersheds of Canada Forest Ecozones
by Percent Accessed, provides a national picture of the
cumulative extent of industrial access within Canada’s
watersheds. The map, Ecosdistricts of Canada Forest Ecozones by Percent Accessed, provides a national picture of the
cumulative extent of industrial access within Canada’s
ecodistricts.
Table 1 presents the area and percentage results of access by forest ecozone as well as nationally. The results
indicate that just over 21 percent of the total area of
Canada’s forest ecozones is accessed. From a regional
perspective, the most accessed are the eastern Atlantic
Maritime and the Mixed Wood ecozones, with each
being more than 75% accessed. The Boreal Plains and
the Montane Cordillera ecozones are also significantly
accessed at 45% and 40%, respectively.
The most northern and remote forest ecozones (the
Boreal Cordillera, the Taiga Shield, the Taiga Cordillera
and the Hudson Plains) each have less than 5% cumulative access.
Table 2 provides statistics on the percentage of accessed
forest ecozone by Province. Four jurisdictions – Alberta,
The three maritime provinces (New Brunswick, Prince
Edward Island and Nova Scotia) each have over 70%
of their forest ecozones accessed. Alberta is the fourth
most accessed province at 47%.
Six jurisdictions – British Columbia, Ontario, Québec,
Saskatchewan, Newfoundland and Labrador, and Manitoba – each have between 10% and 33% of their forest
ecozone area accessed. The Northwest Territories, Yukon and Nunavut each have less than 5% of their forest
areas accessed.
Table 1. Cumulative access by forest ecozone.
Province/Territory
Area Accessed
Province Area
76.4
Boreal Cordillera
2,236,683
47,071,039
4.8
Boreal Plain
33,355,347
74,062,933
45
Boreal Shield
45,948,003
188,640,692
24.4
600,800
37,565,744
1.6
Mixed Wood Plains
Hudson Plains
8,536,603
11,339,105
75.3
Montane Cordillera
19,811,286
48,975,931
40.5
5,689,362
20,873,620
27.3
Pacific Maritime
499,065
26,695,320
1.9
Taiga Plains
Taiga Cordillera
9,620,222
65,773,771
14.6
Taiga Shield
3,915,278
139,314,737
2.8
% Accessed
Alberta
23,837,235
50,672,649
47
31,385,860
94,709,033
33.1
5,909,506
57,883,340
10.2
New Brunswick
5,911,681
7,299,874
81
Newfoundland and Labrador
4,512,746
39,022,812
11.6
Northwest Territories
4,243,873
95,539,825
4.4
Nova Scotia
3,948,814
5,562,603
71
Nunavut
Ontario
Prince Edward Island
1,258
10,786,309
0
25,727,265
98,953,976
26
437,852
593,012
73.8
30,875,057
130,430,760
23.7
Saskatchewan
6,730,055
41,158,212
16.4
Yukon
2,090,600
47,851,969
4.4
145,611,802
680,464,374
21.4
Quebec
Total
% Accessed
20,151,483
British Columbia
Manitoba
Ecozone Area
15,399,153
Table 2. Cumulative access in forest ecozones by jurisdiction.
Province/Territory
Area Accessed
Atlantic Maritime
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Reviews of Cumulative Access
Dataset
A key principle of Global Forest Watch Canada is that
transparency and accountability are essential for developing improved forest management. In the interest of
promoting open, public, and transparent information
policies, most Global Forest Watch Canada projects
include a review process and the publication of a summary of the major comments provided by the reviewers,
including how these comments were addressed.
Resulting from these various direct and indirest reviews
were a few important comments:
Categorization -- The dataset would be much more
useful if the anthropogenic disturbances were categorized (e.g., cutblock, mine site, agricultural clearing, road,
pipeline, seismic line).
GFWC agrees with this comment. However, that was
not the purpose of its derivation and compilation.
This dataset was handled differently than most of our
reviewed products in that it was not specifically developed as a stand-alone dataset. It was developed as a byproduct of our Intact Forest Landscape mapping. The
Cumulative Access dataset is somewhat of the inverse
of the Intact Forest Landscape dataset.
Time-stamp -- The dataset should have been timestamped so that changes over time could be monitored.
The various draft iterations of the Intact Forest Landscape datasets were sent out by invitation to academic
experts as well as to representatives from government,
industry, ENGOs, and First Nations groups. In total, the
various iterations were sent to hundreds of experts and
stakeholders. Over 50 reviewers responded with comments.
Buffering by 500 and 1,000 metres -- The dataset
would be more useful if it was not buffered by 500
metres.
There were two other reviews for the Cumulative Access
dataset that were more direct. For examples:
• A. Schindler, D.W. Comprehensive conservation planning to
protect biodiversity and ecosystem services in Canadian boreal
regions under a warming climate and increasing exploitation.
Biol. Conserv. (2010), doi:10.1016/j.biocon.2010.04.003.
The Cumulative Access dataset was published in this
paper.
• Environment Canada. 2008. Scientific Review for the Identification of Critical Habitat for Woodland Caribou (Rangifer
tarandus caribou), Boreal Population, in Canada. August
2008. Ottawa: Environment Canada. 72 pp. plus 180 pp
Appendices. The Cumulative Access dataset was used
to establish the correlation between woodland caribou herd health and levels of anthorpogenic disturabnces within herd ranges.
The dataset used hundreds of Landsat images over many years.
The vast majority of the dataset does generally date from the
1999-2001 period, with some regional areas uo to 2006.
GFWC agrees with this comment. However, the buffering was
applied as some of the compiled sub-datasets were from the early
2000s and used many Landsat images that were not orthorectified to a high level of geographic positioning accuracy. Buffering by 500 metres for most distruabnces and 1,000 for p[rimary
highways masked many of these problems.
Name of Dataset -- Use of the word “access” in
cumulative access is not appropriate. Should be termed
“disturbance” as several of your items are not related to
access per se (clearcuts, mines. Etc)
Although the title of the dataset may be problematic for some, we
did not want to use the word “disturbance” as it is problematic
for others, based on earlier consultations. The rationale for using
“access” was to provide an appropriate decriptor of the human,
mainly industrial, disutrbances of the landscape that could be
seen in medium-resolution satellite (i.e., Landsat), soe of which
are long term distruabnces, such as in the case of paved roads,
and some of which are mostly temporary, such as in the case of
many cutblocks. The word “access” to GFWC implies both these
ephemeral and more permanent areas of the landscape that have a
visible human footprint.
Who is Global Forest Watch Canada?
Global Forest Watch Canada (GFWC) is an organization whose role is to support the stewardship and conservation of Canada’s remaining forests, by providing
decision makers and civil society with timely, accurate
information on their location, state, and change. In particular, this mission includes monitoring development
activities occurring within and around Canada’s forests,
which influence the current and future conditions of
these ecosystems as well as the people who live within
them. We contribute to a shift toward greater ecological
sustainability in the management of natural areas by creating a compelling visual picture and analysis of current
conditions, historical changes and future trends.
Our vision is that Canada’s forests will be increasingly
well-managed through better information that supports
improved decision-making and, thereby, will provide a
full range of benefits for both present and future generations.
Global Forest Watch Canada provides access to more complete information about development activities in Canada’s
forests and their environmental impacts. We are convinced
that providing greater information about Canada’s forests will
lead to better decision-making on forest management
and use, which ultimately will result in forest management
regimes that provide a full range of benefits for both present
and future generations.
Find out more/contact us:
Website: www.globalforestwatch.ca
Email: info@globalforestwatch.ca
Phone: 780-422-5989
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