Acoustic conditions, conservation planning, and the St. Marys mine

How much external noise can you add to a wetland environment before the wildlife inhabitants really start to suffer?

Relatively little scientific research appears to have been conducted on this subject. Yet an understanding of cumulative noise pollution is essential to properly assessing the long-term impact of the proposed St. Marys Cement under-the-lake mine south of Bowmanville.

A recently published research paper found biochemical markers of increased stress levels, as well as reduced hatching success, among birds chronically exposed to industrial noise. We’ll get to that paper below, but first, here’s a refresher on the setting for the mine proposal.

The St. Marys mine proposal (official Project Description here) describes a mine-entrance tunnel near the bottom of the existing limestone quarry on the Lake Ontario shoreline. The tunnel will lead to under-the-lake caverns, which will be excavated over a 100-year period.

The project site is adjacent to two Provincially Significant Wetlands, Westside Marsh and Bowmanville Marsh. These wetlands are among the remnants of what was once a very extensive array of coastal wetlands all around Lake Ontario. The remaining coastal wetlands are still of key importance to resident and migratory bird populations and to many freshwater fish species who depend on the wetlands at some stage of their life-cycles.

If the project is approved as proposed, 4 million tonnes of limestone will be blasted and hauled out from these caverns each year. The operation will require ventilation fans moving fresh air into the mine and exhaust air back out, to enable work to be conducted throughout a network of chambers that will eventually extend approximately 14 square kilometers under the lake.

Mining trucks will carry the limestone out of the mine and into the quarry, where it will be crushed into aggregate suitable for construction use. Then approximately 500 truckloads per day (based on seven days/week haulage) will leave the St. Marys site carrying aggregate to the primary market on the east side of the Greater Toronto Area.

The environmental viability of the project must be assessed by looking at the cumulative effects. The blasting, drilling, ventilation fans, trucks and crushers will add noise to an environment that is already anything but quiet.

At present both Westside Marsh and Bowmanville Marsh are subject to significant anthropogenic noise levels on a 24-hour basis. The operations of St. Marys are just one component of that noise.

Noise from St. Marys existing operations comes from blasting and hauling limestone immediately to the west of Westside Marsh, trucking of cement products, and major excavation and berm-building directly north of Westside Marsh.

Another constant noise source is Highway 401, just to the north. At present the traffic noise consists of a constant loud hum, punctuated by accelerating trucks, motorcycles, and sirens. The St. Marys mine would add to that traffic noise, as 500 or more additional trucks come and go every day. (The route in and out of the St. Marys property, and on and off the 401, are shown in yellow on the above map.)

One of the busiest rail lines in Canada passes directly north of the quarry, about 500 meters north of Westside Marsh, and through the north end of Bowmanville Marsh.

Above, an eastbound CN freight train skirts the St. Marys quarry and cement plant. Below, a CN freight train on the bridge over Soper Creek at the north end of Bowmanville Marsh.

 

Noise and stress in bird populations

A recent paper published in the Proceedings of the National Academy of Sciences (US) notes that noise pollution “alters habitats, degrades natural acoustic conditions, and partially or fully excludes species that are sensitive to noise exposure from affected areas.”1

Among the species that remain in noise-affected environments, the effects on survival and fitness are complex. One way to study this is to correlate measured noise levels with measured levels of baseline circulating stress hormones (glucocorticoids) in birds. The paper notes,

To date, no studies have simultaneously examined relationships among noise, GCs [glucocorticoids], and fitness in animals that settle and breed in natural areas exposed to chronic anthropogenic noise.

The paper looked at three species of cavity-nesting birds with different noise tolerances, in a New Mexico wildland which is now interrupted by an array of natural gas compressors. The evidence “strongly suggests that chronic anthropogenic noise induces stress and hypocorticism in birds.” Furthermore, with one of the studied species, the western bluebird, increased noise was correlated with a lower rate of hatching success.

There are a number of explanations for the stress response.

At lower exposure levels, anthropogenic noise is more likely to elicit stress responses indirectly by increasing the difficulty of coping with external challenges (e.g., territory defense) or by creating anxiety through reduced detectability and predictability of threats (e.g., acoustic masking of predator alarm sounds), or both.

Given the capacity for chronic noise to consistently mask biologically relevant cues, animals living in areas with high levels of noise may fail to receive information about their local habitats, leading to a continual state of perceived unpredictability and reduced security.

Citing a range of other studies, the authors further explain how chronic noise pollution disrupts the normal sensory perceptions of wildlife.

The distance over which birdsong and other sounds are effectively transmitted, their ‘active space’, is significantly reduced by increases in ambient background noise. Anthropogenic noise, acting as an acoustic blanket, can reduce or inhibit detection of hetero- and conspecific vocalizations that birds and other animals use to gain information about predation threats. For example, the presence of birdsong and chatter is thought to signal the absence of nearby predators.

How does noise pollution affect the wildlife in Westside and Bowmanville Marshes? Are there species which would otherwise make these wetlands home, if it weren’t for chronic noise levels? With increasing noise levels, will some of the existing species be driven out, or will the populations be weakened due to lower reproduction rates? These are complex questions – but they must be answered before the impacts of additional noise, due to a major mining/extraction project, can be properly assessed.

In spite of huge environmental challenges these wetlands remain home to a wide variety of species. Within this small area there are cattail marshes, open water, wetland forest, upland forest, and even a small fen. Among the many species that live here are various waterfowl, fish, wading birds, osprey, kingfisher, beaver, muskrat, and predators including otter, weasel, marten, raccoon, coyote and fox. These wetlands are also vital staging areas for the many migratory birds which fly over Lake Ontario in the spring and fall.

Raccoon on the bank of Westside Creek at the north end of a beaver pond; ospreys which nest each year on platforms in Westside Marsh; juvenile Black-Crown Night Heron photographed in Bowmanville Marsh.

These wetlands are officially designated as “Provincially Significant Marshes”. The review process for the St. Marys under-the-lake mine must make us ask, how much significance does the province actually afford to this environment?

The authors of the paper on noise pollution and avian stress levels note,

In this era of unprecedented, large-scale human-driven environmental change, preservation or recovery of natural acoustic conditions should be a key aspect of conservation planning and is a critical step toward successful conservation of protected species.

Given the importance of natural acoustic conditions to conservation planning, should the province of Ontario give the OK to increased noise pollution from St. Marys Cement?

 


1“Chronic anthropogenic noise disrupts glucocorticoid signaling and has multiple effects on fitness in an avian community”, Proceedings of National Academy of Sciences, 14 November 2017

leaf to leaf

While fall colours quietly creep into woods and wetlands, one group of leaves remains vibrant green: the lily pads. In Bowmanville Marsh and Westside Marsh you may spot a sandpiper treading lightly from leaf to leaf while feeding on aquatic insects, or a beaver swimming from one lily patch to another while happily munching on a flower.

The herons, too, keep watch over lily pads for signs of movement from fish or frogs. Here a young black-crowned night heron hopes for a meal, at the edge of a dense stand of cattails which have lost nearly all their summer colour.

Toehold (click images for larger view)

The fall palette is reflected in the water as a beaver makes a swift passage across the marsh by setting sunlight.

 

Straight Ahead

The resident mute swans are often seen feeding among lily pads – and they leave their mark even when the birds themselves are nowhere in sight.

Feather Two

 

Feather One

 

Sandpipers prove that there are great advantages in being light of weight but wide of foot. On a quiet end-of-summer evening the surface of the marsh teems with insects, and the lily pads make even the deeper waters accessible to this wading bird.

Fast Forward

 

Afloat

In the vegetable garden, meanwhile, another nimble footed creature is springing from leaf to leaf – a grasshopper feasting on collard greens.

Copper Tack

Top photo: Sandpiper Buffet (click here for larger view)

season finale

On a chilly late August morning you may feel that your best-before date has come and gone, your colours have faded and your once-splendid wings are tattered. But by the warmth of the noon-day sun, when you’re sipping nectar from a silphium flower eight feet in the air, you can still make the most of the summer’s glories.

Ragged Red Admiral (click images for larger view)

Once-bright petals are curling and falling to the ground, but a new round of flowers is taking over in meadows and gardens.

Light-Emitting Dandelion

 

Aster

 

Meanwhile the marsh is alive with a profusion of dragonflies and damselflies.

Dark Dragon

 

Dragonfly Sky

 

Whether in the marsh, harbour or along the breakwater, the ducks are no longer skittish – they continue feeding while a kayaker drifts within a few feet.

Duck Diner 1

Duck Diner 2

An adult Black Crowned Night Heron is not a flashy bird, but this nearly full-grown juvenile shows real sartorial flare.

One Fine Heron

Several Great Blue Herons can often be seen in one small part of Bowmanville Marsh.

Wingspan

Along this coast there is another distinct sign of summer’s end: salmon are approaching the mouths of creeks, and that means fishing charters linger near shore while hopeful anglers line the breakwater.

Observation

 

Illustration at top of page: Red Dragon and Blue Dragon

Shiny Things

This week’s photo post is all about things that catch the eye with a flash of sunlight – even when that light is first reflected by the moon.

Campanula. This bellflower, one of the nearly 500 species of campanula, grows well on the shoreline sand dune. (click images for larger view)

 

Hang on. On a breezy summer afternoon this dragonfly keeps a steady grip.

 

Sequined wings.

 

Red currants.

In our garden the first of the summer fruits are just about ready to eat. Meanwhile out in Bowmanville Marsh the water smartweed (persicaria amphibia), whose seeds are snacks for waterfowl and raccoons, is sending up its flowers.

Water smartweed.

Just down the coast, the channel where Westside Marsh meets Lake Ontario is a favoured fishing spot for local birds. As night falls a Great Blue Heron often waits at water’s edge, and if there is still enough light you may catch a glimpse of a shiny fish before it is swallowed in one gulp.

Your turn.

The full moon rising over the lake is a spellbinding sight all on its own. But if a heron chooses that moment to leap from the gravel bar into flight, and you’re lucky enough to have your camera ready, you may as well press the shutter.

That was now.

 

Top photo: Squirrel-tail grass on sand dune. (click here for larger view)

birds birds birds

Today’s post features just a few of the birds seen in the waters, on the shore, and in the treetops in recent weeks in our neighbourhood.

Dive (click images for larger views)

 

Angles

 

Swimming in green

 

Perched

 

Killdeer in dune grass

 

Rocky shore

 

Portrait

 

Night falls

 

Motion studies, or Thanks for all the fish

 

Higher Ground

With Lake Ontario at record high levels, coastal marshes have now spilled over large areas which are normally more or less dry land.

Edges (click images for larger view)

To take pictures along the walking trail along Bowmanville Creek at the north side of Bowmanville Marsh, you need to add hip waders to your photography kit – mere knee-high boots will only get you around the edges of this wetland.

Mirror

Suspension

Though the bare ground has been well under the waters for weeks now, many of the moist woodland species appear to be thriving.

 

In the Catbird Seat

Layers

Mollusc II

The meadow at the east end of West Beach Road, just 100 meters from the Lake Ontario shoreline, also teems with activity.

With masses of rotting wood from generations of huge willow trees along the edge of this meadow, there are billions of ants – now all flushed out of the ground to find a dry perch. Anything sticking out of the water – a blade of grass, stem of last year’s goldenrod, or the odd passing photographer – soon acquires a population of ants. Myrmecophobes be forewarned.

Colonies

But there are bigger animals making the grass rustle – schools of carp now swim and splash through this meadow.

Velocity

Patterns

If you are a bottom feeder this is fine dining.

Mouth

Top photo: Return (click here for larger image)

Marsh monoculture – invasive phragmites and the threat to wetlands

We’ve all seen those amazingly tall reeds with the feathery seed heads that glow in the autumn sunset and last right through the winter, and which have appeared in dense stands on roadsides wherever there’s a bit of water.

Those beautiful reeds are phragmites, and they’re deadly to nearly every other plant, bird, amphibian and predator in our wetlands.

That was the message in a sobering talk by Janice M. Gilbert on April 19. Since there are two big marshes in my neighbourhood, and phragmites are scattered widely in this area, I was keenly interested.

The species of phragmites (pronounced frag-mite-eez) that is causing so much concern is the European common reed. Though it is closely related to a native variety of phragmites, the European version has no natural controls in North America and quickly multiplies into a dense monoculture.

Dr. Gilbert has been researching phragmites and working in phragmites control efforts for the past 10 years. She spoke at the Purple Woods Conservation Area this week, in an event sponsored by Scugog Environmental Advisory Council in partnership with Central Lake Ontario Conservation, Kawartha Conservation, North Durham Nature, Scugog Lake Stewards and Nature Conservancy of Canada.

Gilbert explained that the European common reed is awesomely prolific because nearly every part of the plant will sprout and grow if dropped in wet soil.

It produces a large seed head, and the seeds can be carried for kilometers by the wind – but that’s just one of its strategies for dispersal. Its rhizomes shoot out for many feet in every direction. And if a live stalk is knocked down, it will send up new shoots all along its length.

Dispersal methods of phragmites. (From Invasive Phragmites – Best Management Practices in Ontario)

This explains why phragmites have spread so widely along highways and rural roads. Heavy equipment used in road construction and maintenance, particularly tracked machinery, carries mud from one site to another. If pieces of phragmites are carried in that mud, and it doesn’t completely dry before being dropped in a new location, a new outbreak of the reed will soon be growing.

Spread of phragmites in the Great Lakes area. (From Invasive Phragmites – Best Management Practices in Ontario)

Habitat destruction

Phragmites take over a location so rapidly because they suck up nutrients and water faster than nearly all competitor plants, and because they are allelopathic – their roots secrete chemicals which are toxic to other plants.

Native insect species have not evolved to feed on phragmites – and that means insect-eating birds don’t find food in a phragmites monoculture. Muskrats don’t like phragmites, so they don’t build their characteristic mounds, surrounded by a bit of open water, within phragmites-dominated marshes. Birds will nest right around the edges of phragmites stands, but not very far within – the stands are too dense. And since a fully-developed phragmites monoculture can have 200 stalks per square meter, the growth is so dense that turtles trying to fight their way through are sometimes trapped, succumbing to starvation.

In short, the entire food chain from bottom to top is disrupted when phragmites take over a wetland.

A tale of two marshes

This ecological horror story is of more than passing local concern. There are two important coastal wetlands in my neighbourhood. In one of them – Westside Marsh – there are already major stands of phragmites all along the west side.

Phragmites are established all along the west edge of Westside Marsh, next to the St. Marys Cement quarry. Photo from Nov 2015.

The other local marsh, Bowmanville Marsh, appears to be phrag-free so far – but there are stands of phragmites barely 100 meters away.

This stand of phragmites is along West Beach Road, just north of Bowmanville Marsh.

 

A stand of phragmites on the south side of Hwy 401, near the Liberty Street exit, extends to within a few meters of Soper Creek. This creek flows south and joins Bowmanville Marsh.

 

A long and difficult battle

The good news is that phragmites infestations can be controlled. The bad news is that the process is labour-intensive, it sometimes requires specialized equipment, efforts need to be repeated at least two or three years in a row, and it is almost impossible to get large stands of phragmites knocked back without application of concentrated glyphosate.

Dr. Gilbert described her own gradual conversion to advocating the use of glyphosate – as a wetland ecologist, her first reaction was to recoil at the thought of using herbicides around wetlands – and her frustration that the glyphosate formulations used to great success in phragmites-control programs in the US are not usually available or permitted in Canada.

In our local area, Diana Shermet of Central Lake Ontario Conservation Authority (CLOCA) confirmed that to date, there have been no phragmites-control programs in Westside Marsh or Bowmanville Marsh. High cost is a major barrier, though CLOCA has received funding and carried out phragmites-control programs in a few areas in Durham region.

As Gilbert noted, successful phragmites-control efforts are usually co-ordinated between several agencies. It does little good to get phragmites out of a marsh if there are stands a few meters away along roadsides. And it does little good to get phragmites out of a ditch along a municipal road, if there are stands along a regional or provincial highway nearby.

The Ontario Phragmites Working Group is providing information and expertise to agencies across the province, and we certainly hope that the provincial government, Durham Region, Municipality of Clarington and CLOCA will find a way to take up this effort in the near future.

Top photo: a stand of phragmites in Westside Marsh, photographed in April 2017. (Click here for larger version)

Westside story

In Westside Marsh (just west of Port Darlington, on the north shore of Lake Ontario) the colour scheme is still mostly brown and blue. But the signs and sounds of spring are everywhere, with birds picking out nesting locations and a few already settled down on nests.

An osprey chows down on fresh fish. Unfortunately this bird appears to have a thorn or twig lodged in a nostril – it was clearly visible, sticking out at the same angle, on three different evenings in the past week. (Click image for larger view)

 

A real fixer-upper. The view from this platform is great but the furnishings so far are sparse. (Click image for larger view)

 

These nests are last year’s models but they’ve certainly held together through many strong winds. At left, this nest is only a few feet above ground in a dogwood bush, but its location on a narrow island makes it inaccessible to most predators. At right, this oriole (or possibly red-eyed vireo) nest hangs high in a tree on a hill overlooking Westside Marsh. (Click image for larger view)

Mute swans, which stay in the area through the winter, are already on their nests. (Click images for larger view)

 

These plovers splashing in the shallows at sunset may be just passing through. (Click image for larger view)

 

Beavers are a common sight here, especially in evening when they cross the open water to the wooded edges of the marsh.

Top photo: ospreys perched below one of several nesting platforms in the marsh. (Click here for larger view)

The autumn of winter

Red-wing blackbirds, finches and grackles are returning. Raccoons and skunks are making their rounds at night. How do they all know it’s spring? For the last few days it hasn’t been the warmth of the air – it must be the warmth of the light.

 

‘Stalks’ (click image for larger version)

 

‘River’

 

‘Light Curves’

 

‘Raccoon Road II’ (click image for larger version)

 

‘Contemplation’ (click image for larger version)

 

‘Alternation’ (click image for larger version)

 

Top photo: ‘From a to b’ (click here for larger version)

Sideways Glances

With sunlight in short supply in southern Ontario for the past month and spring greenery still at least six weeks away, it’s been a challenge to capture much colour in outdoor photos. But that makes every brief break in the clouds all the more precious.

These panoramas were composed in the old-school, 1990s way (pieced together in Photoshop from several shots) rather than the new-fashioned way (waving a smart-phone camera at the landscape and choosing the “create panorama” function).

 

Waterway, Saturday afternoon, February 4 (click here for large version)

 

Breakwater/Snowshower, Monday morning, February 6 (click here for large version)

 

Seating is limited, Monday afternoon, February 6 (click here for large version)

 

Top photo: Winter’s Dawn on Bowmanville Marsh, Saturday morning, February 4 (click here for large version)