Download Abstract: Provincial-level land use policies are designed to ensure

NATURAL HERITAGE INDICATORS FOR LAND USE
POLICY EVALUATION
Authors:
BRUCE POND AND MARGARET MCLAREN
Abstract: Provincial-level land use policies are designed to ensure that
features of Ontario’s natural heritage and the associated ecological
functions are maintained and enhanced. The Ministry of Natural
Resources proposes five indicators for broad-scale policy evaluation.
Recognizing contemporary fiscal constraints and a requirement for
historical data for assessing change, the indicators are based on existing
data sources. The indicators are: a) trends in the distribution of human
population, b) trends in forest dependent bird species, c) changes in
streamflow regime, d) changes in conservation ranks of species at risk
and e) trends in land area protected through the Conservation Land Tax
Incentive Program. Here we present the rationale, methodology and
results for the first three indicators. The location of human settlement
and the distribution of population are directly influenced by planning
policy and have a large impact on the natural heritage systems. Trends
in abundance of bird species that require substantial forested area for
successful breeding may reflect loss of forest cover. An increasing
divergence of high and low stream flows indicates a potential impact on
fish habitat structure and volume and may reflect a development effect of
increased impervious land surface.
CONTEXT
Increasingly, public agencies recognize that reporting on the state of their jurisdiction and their
management performance is a required component of being accountable to their constituents and
stakeholders. Recent reporting efforts by land use planning and resource management agencies
focus on providing assurances of the sustainability of current forest management practices. The
Ontario Ministry of Natural Resources is currently producing a State of the Forest report to meet
reporting requirements of the Timber Class Environmental Assessment and the Crown Forest
Sustainability Act. The Ministry is also responsible for broad-scale provincial-level reporting on
the performance of the Provincial Policy Statement (PPS) of the Planning Act (Ministry of
Municipal Affairs and Housing 1997) in the areas of aggregate resources, natural heritage and
natural hazards. The development of outcome-based performance indicators is one component of
this policy review.
The focus of this paper is on indicators for assessing the performance of the natural heritage
sections of the PPS. The direction in the policy statement with regard to natural heritage is
summarized in Table 1. An earlier paper (Pond et al. 1998) reports on a framework for indicators
in which criteria for indicator selection were developed (Table 2). Ideally, indicators should meet
all these criteria as fully as possible. In practice, trade-offs are required and in this case two
overriding criteria constrained the selection of indicators:
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i. that data be available with no new data collection initiatives; and,
ii. that a province-wide historical record exist to permit analysis of geographic patterns and
trends over time.
Table 1: Natural heritage components of the Provincial Policy Statement (MMAH 1997)
• Development is not permitted in significant wetlands south and east of the Canadian Shield
or in significant portions of the habitat of endangered and threatened species.
• Development may be permitted in and adjacent to fish habitat, significant wildlife habitat,
ANSIs, wetlands on the Canadian Shield, and significant woodlands and valleylands south
and east of the Canadian Shield only if it is demonstrated that there will be no negative
impacts on the features or their ecological function.
• The diversity of natural features in an area and the natural connections between them
should be maintained and improved where possible.
Table 2: Selection criteria for indicators (Pond et al. 1998)
• Policy-outcomes oriented, not process measures
• Available, accessible and accurate data.
• Relate to specific societal or environmental
concerns.
• Relevant to articulated goals and objectives
• Comparable over time.
• Timely
• Understandable to potential users.
• Scientifically valid.
• Unambiguous.
• Statistically and analytically sound.
• Easy-to-use.
• Demonstrated practicality.
• Appropriate for scale for decision-making.
• Historical record.
Given these constraints, the indicators for assessing the PPS that are currently developed and
proposed are:
•
•
•
•
•
Trends in human population
Trends in forest dependent bird species
Trends in annual streamflow variability
Change in species’ conservation status ranks
Trends in land protected under Conservation Land Tax Incentive Program
We present descriptions of the first three of these indicators, the data sources, methods and
preliminary results.
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HUMAN POPULATION
Human settlement disturbs natural ecosystems with greater intensity and at greater temporal and
spatial scales than do natural disturbance regimes. In general, high human population densities
have a detrimental impact on natural features and their functions. Rates of population change in
settlement areas and rural and transition areas indicate, at a broad scale, how well population
growth and development are being directed into existing settlement areas and away from rural
areas, where most significant natural heritage features are located.
This indicator uses population counts and digital maps of 1996 census enumeration areas to
calculate population densities and delineate settlement, transition and rural areas. The
breakpoints for this density-based classification are i) >0 and <50 persons/km2 for rural areas ii)
>50 and <100 persons/km2 for transition areas and iii) >100 persons/km2 for settlement areas.
Population data at each of the census years 1981, 1986, 1991 and 1996 are summed within each
of the 1996 density classes.
Population in the province increased by 25 percent over the 1981-1996 period, with the largest
proportion of that growth occurring between 1986 and 1991 (Table 3 and Figure 1). Growth rates
in rural and transition areas were lower than in settlement areas, except in the 1986-1991 period
when growth in transition areas was highest of any class and time period. Although rural and
transition areas constitute a relatively small part of the population of the province (15 percent),
continued population growth in these areas will have a significant cumulative impact on natural
heritage features and ecosystem processes. Highest growth rates were centred on Toronto and
Ottawa (Figure 2). During the 1986-1991 period of high growth there was a disproportionate
increase in population in rural areas. This effect is most evident in the area within commuting
distance of Toronto and Ottawa. These areas will require further monitoring to ensure the
integrity of natural heritage features is protected.
Table 3: Ontario population trends in 1996 density classes
Population Counts
Rural
1981
1986
1991
1996
Annual change 1981-86
Annual change 1986-91
Annual change 1991-96
1,291,280
1,306,194
1,401,873
1,405,048
0.2%
1.4%
0.0%
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Transition
150,870
157,087
187,346
198,234
0.8%
3.6%
1.1%
3
Settlement
7,182,957
7,638,413
8,495,658
9,150,291
1.2%
2.2%
1.5%
Province
8,625,107
9,101,694
10,084,877
10,753,573
1.1%
2.1%
1.3%
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Figure 1: Ontario population trends by 1996 density classes
10,000,000
2,000,000
8,000,000
1,600,000
6,000,000
1,200,000
4,000,000
800,000
2,000,000
400,000
0
0
1981
1986
1991
Ce nsus Ye a r
1996
Rural/Transition
Area Population
Settlem ent Area
Population
Ontario Population Tre nds
in 1996 Population De nsity Classe s
Settlement
Rural
Transition
Figure 2: Map of population change 1981-1996
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FOREST DEPENDENT BIRD SPECIES
This indicator compares the trend in abundance of selected forest-dependent bird species to the
trend observed for the same species during migration. The indicator is based on a comparison of
trends because conditions beyond Ontario affect these migratory species. Both locally and
provincially, the trend can be increasing, stable or decreasing but only three possible
combinations (locally decrease with a provincial increase, local decrease with provincially stable
levels, or locally stable with a provincial increase) can be interpreted as meaning that the policy
may not have been implemented or may not be effective.
The selected species have been empirically determined to occur in smaller numbers or not at all in
small woodlands (Robbins et al. 1989; Freemark and Collins 1992) and woodlands surrounded by
housing development (Friesen et al. 1995). If the policy is effective, then there should be no
difference in trend in abundance of the sensitive species between the agricultural/urban landscape
of southern Ontario and the trend for the broader landscape observed in the migration data.
Local trends for each area-sensitive and development-sensitive species were calculated using
linear regression techniques for six regions of southern Ontario selected for their similarity of
forest cover. Local trends were derived from the Forest Bird Monitoring Program (FBMP)
administered by the Canadian Wildlife Service. Provincial trends for the same species were
calculated using data collected at Long Point Bird Observatory during migration. The average
trend in the FBMP data and migration data for each species was compared by geographic area
using paired t-tests.
Comparison of trends in abundance from 1990 to 1999 showed statistically significant differences
for all geographic regions (Table 4). Even though the average trends are different statistically,
most differences are very small. Nevertheless, the most significant of those differences occurs in
southwestern Ontario, the area with the lowest forest cover.
Table 4: Statistical summary of forest dependent bird indicator analysis
Location
Southwest
Grey-Bruce
Southcentral
GTA
Simcoe,
Peterborough,
Northumberland
East
15
21
18
15
FBMP Mean
Change in
Abundance
-0.015
0.002
-0.006
0.001
LPBO Mean
Change in
1
Abundance
0.032
0.038
0.036
0.046
Difference
between LPBO
and FBMP
0.047
0.036
0.042
0.045
18
-0.011
0.036
22
0.003
0.037
No.
Species
t-value
Significance level
-7.107
-4.309
-4.476
-4.164
<0.001
<0.001
<0.001
0.001
0.047
-5.553
<0.001
0.034
-4.542
<0.001
1
Mean changes for LPBO data vary because different species combinations are used in different geographic areas.
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The changes that this indicator is intended to measure have most likely been occurring
continuously since major land clearing began in southern Ontario during the 1800s. That the
results of this analysis were consistent with theoretical expectations suggests that ecological
function of woodlands was still being lost between 1990 and 1999.
STREAMFLOW VARIABILITY
Trend over time, as measured by linear regression parameters, in the ratio of high to low flows in
rivers and streams indicates a potential effect of development on streamflow patterns and thus on
fish habitat. An increasing trend may occur because of increased area of impervious surfaces
(e.g. roads, driveways, rooftops). This has the dual effect of i) reducing rainfall infiltration,
consequent contribution to streamflow, and thus fish habitat volume and ii) increasing the speed
and volume of direct storm runoff into streams, which alters fish habitat structure and water
quality.
Figure 3: Examples of increasing, stable and decreasing trends in the streamflow variability
indicator
Trends in Streamflow Variability
Ln (5%exeedance flow / 95% exceedance flow)
6
5
4
3
2
1
0
1970
1975
1980
1985
1990
1995
Year
HOLLAND RIVER AT HOLLAND LANDING
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The data for this indicator, taken from the National Water Data Archive maintained by the Water
Survey of Canada, are daily stream flows measured at gauging stations throughout Ontario
between 1970 and 1999. An annual index of flow variability was computed as the ratio of high
flow to low flow (Richards 1990). Data were taken only for the warm months (April-November)
to avoid confounding effects of snow melt and frozen ground surface. The value used for low
flow was that daily flow which was exceeded by 95 percent of all warm month daily flows;
values for high flow was that which was exceeded by only 5 percent of warm month daily flows.
Figure 3 shows the indicator for three streams, illustrating increasing, stable and decreasing
trends in the indicator.
Provincially, 11 percent of the gauged streams showed a significant increase in the streamflow
variability index, 7 percent experienced a significant decrease (Table 5). Compared to the
province, southwestern Ontario and the Greater Toronto Area had greater proportions of streams
with increasing trends relative to the proportion with decreasing trends. At the scale of the
individual gauging station the indicator is useful in identifying long-term changes in flow
regimes. At both scales further research would need to be undertaken to attribute the change to
particular causes, one of which might be development.
Table 5: Significant trends in streamflow variability indicator (p = .10)
Southwest
Stations with Increasing Trend
Stations with Decreasing Trend
Total # of gauging stations
4 6%
2 3%
62
Central
8 11%
7 10%
70
GTA
8 21%
0%
0
39
East
8 15%
7 13%
56
North
9
9
110
Province
8%
8%
37 11%
25 7%
337
CONCLUSIONS
The indicators reported here will not unequivocally identify the effect of the recent changes in
land use policy, or even changes in land use. There are a number of alternate explanations for the
trends that they show, ranging from climate change through agricultural policy to the state of the
global economy. There is also a great deal of inherent variability in the indicators, which
necessitates the use of long-term data sets for trend assessment. In the short term, identification
of effects of recent policy change is better achieved through consultation with actors and
stakeholders in the planning process. Over the longer term, these “flag” indicators, which serve
to identify potential problems, can be augmented with other more expensive indicators that have
more diagnostic power to identify particular causes. Such indicators would include direct
measurements of the timing and location of land development from satellite imagery or from
administrative property records and the use of statistical samples designed specifically for the
purpose of land policy evaluation. In the meantime, the indicators reported here function as
benchmarks for some components of the policy and serve as the first step in an iterative process
of improving the indicators and ultimately improving the planning system so that it meets its
articulated objectives.
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ACKNOWLEDGEMENTS
David Hussell, OMNR Scientist Emeritus, developed the method for determining the annual
indices of abundance. Mike Cadman, Canadian Wildlife Service, provided the FBMP data and
Charles Francis, Bird Studies Canada, provided the Long Point indices.
REFERENCES
Freemark, K. and B. Collins. 1992. Landscape ecology of birds breeding in temperate forest
fragments. In Ecology and Conservation of Neotropical Migrant Landbirds, ed. J. Hagan and D.
Johnston, 443-454. Washington: Smithsonian Institution Press.
Friesen, L.E., P.F.J. Eagles and J.R. MacKay. 1995. Effects of residential development on forestdwelling neotropical migrant songbirds. Conservation Biology 9:1408-1414.
Ministry of Municipal Affairs and Housing. 1997. Provincial Policy Statement. Toronto:
Queen’s Printer for Ontario. [online]: http://www.mah.gov.on.ca/business/policye/table.asp
OMNR. 1997. Natural heritage training manual for Policy 2.3 of the Provincial Policy
Statement. Peterborough: Ontario Ministry of Natural Resources.
Pond, B., M. Boyle and J. J. Kay. 1998. State of the landscape reporting: A framework for
indicators of land use policy performance. Paper in Leading Edge ’97: The Edge and The Point
Conference Proceedings, ed. S. Carty et al., 207-213. Georgetown, Ontario: Niagara Escarpment
Commission.
Richards, R.P. 1990. Measures of Flow Variability and a new flow-based classification of Great
Lakes tributaries. Journal of Great Lakes Research 16:53-70
Robbins, C.S., D.K. Dawson and B.A. Dowell. 1989. Habitat area requirements of breeding
forest birds of the middle Atlantic states. Wildlife. Monographs 103:1-34.
CONTACTS
Bruce Pond
Ontario Ministry of Natural Resources
300 Water St. 3rd Floor N
Peterborough, Ontario
K9J 8M5
Telephone: (705) 755-1546
Fax: (705) 755-1559
Email: [email protected]
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Margaret McLaren
Ontario Ministry of Natural Resources
R.R. #2
Bracebridge, Ontario
P1L 1W9
Telephone: (705) 646-5545
Fax: (705) 645-7379
Email: [email protected]
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