October 23, 2015 – Fall is in the air, and many of us have our sights set on seeing the beautiful Ontario fall colours. Although our first instinct may be to drive north for an hour or more to take in the countryside, those unfamiliar with Oakville’s ravine systems may not know that there are natural gems hidden right next door. If you live in or have access to west Oakville, fall is a wonderful time to visit the natural lands at Fourteen Mile Creek.
Fourteen Mile Creek is mainly an urban and suburban creek, with only its outermost roots stretching outside of the city. And yet, when given a chance, there is a vibrant natural community hidden in its deep, winding ravines.
The outer fringes of this natural area are thick with regenerating forest, recovering slowly from a history of land clearing, farming, and urbanization. It is a mix of natural regrowth, planted native species, and unfortunately, a generous mixture of invasive plants like Common Buckthorn, Garlic Mustard, Common Privet, and Norway Maple. However, in time, and with management, this forest may be sculpted to match the more natural remnant communities further in.
Once inside the highly disturbed young “fringe” of the forest, a remnant forest ecosystem comes to life, and in full colour. A forest of Sugar Maple (Acer saccharum subspecies saccharum) opens up, with undertones of Ironwood (Ostrya virginiana), White Ash (Fraxinus americana), American Beech (Fagus grandifolia), Eastern Hemlock (Tsuga canadensis), Red Maple (Acer rubrum), Basswood (Tilia americana), White Birch (Betula papyrifera), White Pine (Pinus strobus) and others.
Fourteen Mile Creek’s deciduous forests coat the ground each fall in a dazzling display of fall leaves. These leaves are vital to the functioning of the native deciduous forest. They cover the ground in a thick layer, which provides habitat for insects, birds and other animals, returns nutrients to the soil, provides food for fungi, and acts as a kind of natural insulating ‘mulch’ for native plants.
Many native forest plant species – such as Ontario’s provincial flower, the White Trillium (Trillium grandiflorum) – are specifically adapted to thrive with a thick layer of leaf litter. Loss of leaf litter is destructive to the whole ecosystem, and allows invasive plants like Garlic Mustard to establish much more easily.
Moving from the level upland areas to the sloping and close-knit ravines and ravine tributaries, a subtle but defining change occurs – this time, harder to perceive without a trained eye. Elements of historic biodiversity and higher habitat values begin to show – the Sugar Maple and American Beech forest type, scattered Eastern Hemlock trees on the shaded slopes, and an enriched forest floor grace the less-traveled areas. Understory shrubs, ferns, and downed decomposing trees bring the forest closer to a natural state.
Long ago, before European settlement cleared so much of Ontario, this Sugar Maple and American Beech-dominated forest ecosystem was abundant not only in the ravine systems of Fourteen Mile Creek, but across much of the Carolinian life zone. This life zone of Ontario roughly covers everything south of the line between Toronto and Grand Bend, and it was once almost entirely covered in trees.
Why were Sugar Maple and American Beech so common? They are what we call “shade tolerant” tree species, meaning they don’t need full sun to grow. Even with a full canopy of mature trees above, new saplings of the next generation are able to grow strong in the shade and eventually replace the old trees in an even, unbroken cycle. Trees that are bad at this – like White Birch – need something to break the canopy, and let in more light.
With a province that was covered in tree canopy, what better way was there to thrive than being shade tolerant?
Where the ravine slopes and hill crests face the sun, the less-disturbed areas harbor many beautiful ground plants. Spring wildflowers, low flowering shrubs and grass-like sedges put on a colourful show in spring and fall, cresting the drop to the main creek itself. Unique plants like Low Sweet Blueberry, Wintergreen and Beechdrops crop up … and a myriad of shades of Maple-leaved Viburnum. These are the living fingerprints of what would otherwise be a bygone era in Oakville, were it not for the continued preservation of areas like Fourteen Mile Creek and its natural lands.
Below, in the very heart of the largest ravine, the main channel of Fourteen Mile Creek cuts through the floodplain. Although not a huge creek, and even in spite of being mostly surrounded by city, it may be surprising to realize that many species of fish, amphibians, birds, mammals, and insects call this creek home. One simply has to look, listen, and pay attention to the details – and the signs of wildlife will show through!
Not “just any” fish habitat
It is tempting to make assumptions about the quality of fish habitat in an urban creek like Fourteen Mile. However, the truth might surprise you! Many fish use these urban creeks, both temporarily for spawning and permanently year-round – and with its diverse stream habitats, Fourteen Mile is no exception. In fact, it exceeds expectations.
Did you know?
Conservation Halton does routine fish monitoring in its creeks. In 2014, Fourteen Mile Creek was one of only three urban creeks in all of Burlington and Oakville that had a diverse enough active fish community to get a “Good” water quality rating at any of its checkpoint stations. “Good” is the highest rating any checkpoint obtained.
Fourteen Mile Creek was also the only Halton urban creek in 2014 to show a population of the sensitive and endangered Redside Dace (Clinostomus elongatus). This was a feat that not even high-profile Bronte Creek could match that year.
At the end of the day, a walk in Fourteen Mile Creek quickly proves that in Oakville, you don’t have to go far from home to experience a beautiful natural setting. So long as we keep a space alive for nature, it will continue to surprise and delight us.
The next time you are in the neighbourhood, why not take a look? You might be surprised that such a small creek can have so much heart!
All photos and text provided by ecologist, David d’Entremont.