The Canadian Wildlife Service Acid Rain Program
As part of the federal government's Long Range Transport of Air
Pollutants (LRTAP) Program, the Canadian Wildlife Service (CWS)
initiated a research program in 1980 to assess the impacts of acid
rain on wildlife and their habitats in eastern Canada. Its objectives
were to determine which species and habitats were most at risk from
acidification, and to establish cause-and-effect relationships between
acid rain and biological changes, chiefly in bird communities.
In Ontario, the program focussed on the chemical and biological
effects of acid rain on small lakes and wetlands in the boreal shield
ecozone of central and north-eastern Ontario. From the outset, the
Ontario program has taken an integrated, whole ecosystem approach,
by collecting and analyzing data on water chemistry, watershed characteristics,
and the structure and biodiversity of aquatic food chains, with
particular attention paid to organisms at the top of these food
chains, notably waterfowl and loons. Research through the 1980s
led to the development of the Acid Rain Biomonitoring Program in
1987, which continues today. The mandate of the program is to verify
the progress of acid rain control measures in Canada and the U.S.,
and to determine if these measures will provide the necessary environmental
protection to support the recovery of healthy biological communities
in aquatic ecosystems in eastern Canada.
Various LRTAP Project and Information Holdings for Biomonitoring
and Research Programs, contained in WILDSPACETM, are
listed below and linked to metadata descriptions:
Acid Rain Biomonitoring in Ontario's Lakes
The CWS (Ontario Region) Acid Rain
Biomonitoring Program stands alone as the only broad-scale biological
effects monitoring program in Canada whose focus is acid-sensitive
aquatic ecosystems. Its goal is to verify that acid rain control
programs in Canada and the United States are protecting aquatic
ecosystems important for wildlife by integrating biological and
physical/chemical monitoring data from freshwater lakes and wetlands
to assess both the degree of environmental improvement achieved
in these habitats and the adequacy of control programs.
Why do we need to monitor biological systems? The adequacy of acid
rain control programs must be measured in terms of the capacity
of aquatic habitats to sustain healthy populations of plants and
animals, both fish and wildlife, and cannot simply be assessed in
terms of measured reductions in acidic deposition or improvements
in water quality. Biological monitoring is necessary to confirm
that steps taken to protect and improve damaged ecosystems are having
an effect.
Our approach is to undertake sufficient regional monitoring so
that chemical and biological trends may be resolved from normal
variation. Collect long-term ecological data to evaluate (at several
spatial and temporal scales) the recovery of acid-sensitive lakes
and wetlands that are expected to respond to reduced acid deposition.
Study Areas and Characteristics:
Monitoring studies are targeted in three distinct regions in the
Boreal Shield Ecozone of Ontario (Algoma, Muskoka, and Sudbury)
that differ in historical effects of, and in anticipated responses
to, sulphur and nitrogen deposition (see
study sites). Collectively, nearly 600 water bodies are monitored.
These lakes and wetlands tend to be small (less than 20 hectares
in size, often headwaters), cover a broad pH range, are often fishless
(about 40%), and include extremely damaged lakes near Sudbury (see
chart). Monitoring the recovery of acidic and damaged lakes
in the Sudbury area following recent, significant reductions in
local smelter emissions (copper
and nickel refining), provides a unique natural experiment to study
the recovery of biotic communities following reversal of acidification
at a much more accelerated rate than expected elsewhere in eastern
Canada.
Canadian Lakes Loon Survey (CLLS):
Loons are an excellent indicator of how lakes are recovering or
suffering from acid rain, because acid rain causes significant declines
in the populations of fish, on which they prey. Since two adult
loons require more than 180 kilograms of fish during the summer
to raise one chick, breeding success is lower on acid lakes where
young may starve from lack of food. Acid rain also leaches toxic
metals, such as mercury, from soils and sediments. These metals
can bioaccumulate in the food chain and affect reproduction.
For the past 20 years, surveyors with the CLLS - a volunteer-based
program supported by Environment Canada and other partners, and
administered by Bird Studies Canada http://www.bsc-eoc.org/cllsmain.html
- have monitored the breeding success of loons on up to 800 lakes
annually across Canada. In Ontario, about 1,600 lakes have been
surveyed through the CLLS; these lakes are typically large (over
40 hectares in size), and clear, with most above pH 6.
Study Components: The CWS
(Ontario Region) Acid Rain Biomonitoring Program is made up of four
main components: (1) water chemistry monitoring, (2) water bird
monitoring, (3) aquatic food chain monitoring, and (4) predictive
modelling (see chart). The first
three components are directed at establishing whether there are
changes occurring in lake chemistries in response to reduced sulphate
deposition (i.e. chemical recovery), and if corresponding changes
are occurring in aquatic food chains and top predators (i.e., biological
recovery). Monitoring, therefore, provides real measures of regional
biological change over time in response to emission controls. Using
these data, biological models (fourth component) are developed,
validated and tested to assess regional impacts, evaluate critical
loads, and predict the response of biota to future emission reduction
scenarios. Modelling, therefore, uses real data to predict responses
in other areas, to assess impacts, and evaluate critical loads (see
chart).
1. Water Chemistry Monitoring
(See water chemistry)
Goal
- to establish annual chemical conditions and detect temporal
trends in the chemistry of small lakes and wetlands (<20 ha
in size, minimum 0.4 ha), that are important habitat for wildlife,
in three acid-sensitive regions of Ontario that are expected to
vary in their response to sulphur emission reductions
- to determine the nature, rate and extent of short-term chemical
recovery in damaged Sudbury area lakes, where improvement is expected
to occur more rapidly than elsewhere in eastern Canada due to
historical damage and rapid local emission reductions
Location and Sample Size (See
chart)
- Algoma (224 lakes), Muskoka (219 lakes), Sudbury (141 lakes)
- Directed sampling of 50 large lakes (> 20 ha) surveyed for
fish-eating birds in the Sudbury and Muskoka-Haliburton areas
- Sample for 22 chemical parameters (pH, alkalinity, conductivity,
base cations (Ca, Mg, Na, K), anions (SO4, Cl, SiO2),
nutrients (TP, TN), dissolved organic carbon and trace metals
(Al, Fe, Mn, Cu, Ni)
Approach
- sample all 62 core food chain lakes and 50 fish-eating bird
lakes each year
- sample other biomonitoring lakes on a 3 year, rotational basis
(Algoma - 88 annually of 224 total; Muskoka - 86 of 219 total;
Sudbury 93 of 141 total)
- sampling is conducted by helicopter at the time of autumn turnover
(early October)
- data undergoes a rigorous testing procedure, including ion balancing
and outlier analysis
- use customized software to conduct conservative, non-parametric
statistical trend analyses
Results
For the three study areas pooled, trend analyses on chemical data
collected between 1988 - 1997 suggests that about 70% of the lakes
have shown no significant change in acidity status (pH or alkalinity),
while 25-30% of the lakes have shown some significant improvements,
and a few lakes have gotten worse (see
table). Half of the lakes have exhibited significant declines
in base cation (especially calcium and magnesium) and 40% have exhibited
significant declines in sulphate. It is this decline in base cations
that is thought to have offset the reduction in sulphate, thereby
minimizing the anticipated improvements in pH or ANC. Since 1983
at Sudbury, 47% have decreased in sulphate, 42% in base cations,
and 16% have increased in pH (see Trends
in Acidity Status and Recent
pH Changes in CWS Biomonitoring Lakes). Climatic variability
arising from drought conditions in 1986 and 1987 followed by wet
years in 1988 and 1989 derailed chemical recovery in many lakes.
Note that there has been little change in nutrient - related parameters,
such as total phosphorus or dissolved organic carbon.
2. Water Bird Monitoring
(See surveys)
Goal
- by helicopter, count numbers of indicated breeding pairs and
broods of 8 main water bird species to establish patterns and
shifts in habitat use and reproductive success by water birds
breeding in acid-sensitive regions of Ontario, and through time
track temporal trends in these parameters to examine the rate
of biological recovery in response to chemical recovery of small
lakes and wetlands (< 20 ha)
- principle waterbird species observed are piscivores: common
loon (Gavia immer), common
merganser (Mergus merganser); dabbling ducks: mallard
(Anas platyrhynchos), American
black duck (Anas rubripes), wood
duck (Aix sponsa); and diving ducks: hooded
merganser (Lophodytes cucullatus), ring-necked
duck (Aythya collaris), common
goldeneye (Bucephala clangula).
- on a selected set of larger lakes (> 20 ha), conduct ground
surveys to locate nests (clutches) and count indicated breeding
pairs and broods of fish-eating birds (common loons, common mergansers,
great blue herons, ospreys, belted kingfishers) to measure changes
in reproductive success of the most directly affected birds
- provide support for the Canadian Lakes Loon Survey, administered
by Bird Studies Canada, volunteer-based activities in Ontario
Location and Sample Size (See
chart)
- wetland-specific breeding pair and brood surveys (by helicopter):
Algoma (224 lakes), Muskoka (219 lakes), Sudbury (141 lakes)
- site-specific monitoring of the use of duck boxes by cavity-nesting
waterfowl on Sudbury lakes (n=75)
- Monitoring of fish-eating birds across 50 larger lakes in Sudbury
(n=15), Killarney Provincial Park (n=10) and Muskoka-Haliburton
(n=25)
- linked to continental waterfowl population surveys through other
CWS (Ontario Region) programs such as the Black Duck Joint Venture;
annual surveys conducted throughout central and northeastern Ontario
cooperatively with acid rain monitoring
Approach
- 2-year rotational basis; survey lakes (by helicopter) in May
for evidence of breeding (nesting habitat suitability); return
in July and survey for broods (survival suitability)
- each year, conduct 3 ground surveys (first weeks of July, August
and September) to locate nests, and count breeding pairs and young
of fish-eating birds
Results
- to date, 3,815 lake-years of records suggest an overall higher
production of water bird young from mid and high pH lakes, and
that habitat use differs among guilds. Piscivore indicated breeding
pairs and broods show proportionatly higher use of high pH lakes,
whereas dabblers show a relatively uniform distribution of habitat
use across the pH range, perhaps with slightly higher use of mid-pH
lakes. Diving ducks show a distribution skewed opposite to piscivores,
that is, higher use of low pH lakes (below pH 5.5) by nesting
pairs, with broods showing a more uniform distribution. The realtively
higher occurrence of common goldeneys on low pH lakes near Sudbury
has a strong influence on the patterns exhibited here (see
chart).
- CLLS results show that between 1981 and 1997, the proportion
of successfully breeding loons in Ontario has declined and that
the rate of decline was more extreme on lakes with high acid levels
than on well-buffered lakes - especially in recent years.
- larger, higher pH lakes are more likely to support pairs and
broods than smaller or more acidic lakes
- evidence of recent (1985-1996) piscivore population increases
near Sudbury supports model predictions for that area (see
chart)
- both pH and lake size have a strong effect on the occurrence
of fish, which in turn directly influences nesting habitat suitability
for fish-eating birds (see chart)
3. Food Chain Monitoring Program
(See program)
Goal
- to detect changes in the status, composition and abundance of
aquatic macroinvertebrates, fish and amphibians (major waterfowl
and loon prey) in response to changes in the chemistry of small
lakes and wetlands in three acid-sensitive regions of Ontario
Rationale
- there are several reasons why chemical data alone are inadequate
to assess environmental improvements; for example, biological
response lag times (hysteresis), variable dose/response thresholds
or recovery pathways, predator/prey interactions (e.g. fish/invertebrates)
during recovery and interactions with other stressors (surprises
which derail recovery). There is a need for better understanding
of how recovery processes will permeate food webs to reach top
predators (fish, birds, mammals, etc.) in acidified systems, and
of the geographical scale of recovery required to increase populations
in dispersed organisms, such as birds.
Location and Sample Size
- Algoma (20), Muskoka (20) and Sudbury (22) food chain lakes
were chosen to represent the range of pH and fish status (presence/absence)
in small lakes (2-10 ha) that are typical breeding habitat for
waterfowl across this region
- 41 samples are collected per lake (See
chart)
Approach (See
table)
- use standardized protocols and identification procedures to
sample selected lakes at each study site during June on a 3 year,
rotational basis
- sample in mid-June to coincide with period of maximum brood
activity on boreal lakes
- sample principle prey items of local waterbirds (macroinvertebrates,
small fish and amphibians) from the littoral zones of selected
lakes. Sampling methods include sweeps (primarily for nekton),
hoops (for trichopterans), benthic drags (odonates, trichopterans,
molluscs), funnel traps (for leeches) and minnow traps (for small
fish and amphibians, as well as large nekton like belostomatids).
- survey indicator species recovery (leeches) on 40 lakes at Sudbury
- all specimens are submitted for identification to established
taxonomic authorities (experts) using recognized identification
keys; representative samples of each species are maintained in
a reference collection, and remaining samples are archived and
stored for easy reference
Results
- more than 10,000 fish (mostly small, non-game species) and 30,000
invertebrates sampled to date, representing > 250 species
- results demonstrate that presence and/or type of fish community
in lakes will in part dictate the configuration of the recovering
macroinvertebrate communitiy (i.e. in addition to lake chemistry),
and hence the quality of the lake for various water birds
- clear evidence of reduced biodiversity with decreasing pH; evidence
of reduced nutritional quality (lower Ca levels) of invertebrate
prey from more acidic lakes; no evidence of substantive recovery
of damaged lakes since 1987, even in the Sudbury area where some
chemical improvements have been detected in certain lakes
4. Predictive Modelling
(See WILDSPACE and WARMS)
Goal
- to acquire, verify and assess quality of data, and to incorporate
those data into existing databases, interpret trends, and use
existing information to make predictions (i.e. modelling) about
the eventual status of ecological components of aquatic ecosystems
in eastern Canada under various emission scenarios
Location and Sample Size
- CWS wildlife models are based on data collected from Ontario
(see chart)
- CWS data have been used to develop fish models for eastern Canada
- chemical and physical data collected for > 5,000 lakes in
eastern Canada
Approach
- use standardized and verified QA/QC protocols for checking of
annual chemical and biological data; verify physical data against
new GIS databases for lake attributes
- use custom-designed software, the WILDSPACETM Decision
Support System (See Decision Support System 1,
2, 3),
and the Waterfowl Acidification Response Modelling System ("WARMS")
(See WARMS 1, 2,
3) to predict chemical and
biological effects of legislated and suggested emission reduction
scenarios in Ontario and elsewhere in eastern Canada
- use models to assess regional critical loads in eastern Canada
Results
- For pH, most chemical changes where current lake pHs are between
5 to 6, with lakes pH < 5 or pH > 7 staying about the same.
Recommended further 75% emission reduction from 2010 targets should
result in over 80% of eastern Canada supporting lakes with pH
above 6 (i.e. above critical load levels).
- Once steady-state conditions are achieved following the 2010
emission levels, no change in nesting habitat suitability is predicted
for most (73%) of eastern Canada, but small to large improvements
will occur in central Ontario and Quebec, notably near Sudbury
and Rouyn-Noranda.
- Collectively, the projected changes in pH and changes in habitat
suitability confirm that each emission scenario results in some
improvements to the chemical conditions and nesting habitat suitability
of water bodies in eastern Canada. A large proportion of the land
mass will not change, either because lakes in certain areas are
well-buffered, or do not receive enough deposition to cause chemical
deterioration. As well, for nesting piscivores, many lakes will
not change in suitability simply because they have characteristics
that make them unsuitable for nesting (e.g. too small, too shallow),
irrespective of lake chemistry.
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