Category Archives: environment

Strategies on Recycling & Waste Reduction in Halton Hills

Opening the event addressing global waste problems, Dr. William McIlveen gave an interesting look into how humans and their environmental impacts evolved over time. Loss of habitat and species extinction relayed a sense of urgency to take collective action regarding waste reduction.
Although a pretty grim picture was painted, he ended on a positive note. There is something you can do about it.
A more detailed account of the event can be found in this month’s newsletter. Esquesing Volume 54 Number 2
Listed below the photo gallery are the resources and links to the presentations and Display Board posters from our event.

7 options to consider before recycling
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Bill McIlveen’s Opening Act: Perspectives on Human Impacts
Fiona’s Presentation: Talking of Trash
David Suzuki Foundation: Five Ways to Recycle Less
Ecobricks: Building with Waste
The EIGHT R’s of waste: Rethink Refuse Reduce . . .
Local Businesses & Farms Helping the Environment!
Staples Recycling Program: Accepted Waste
Staples Recycling Program: More Accepted Waste
Queen of Green: Green Cleaning Recipes

Norval BioBlitz

It is hard to believe it has already been almost three months since the rare-Norval BioBlitz. Before we slip into winter hibernation I want to bring you back to the warmth and exciting discovery that day.

As a recap, a BioBlitz is an event that attempts to count as many species as possible in a given area and timeframe. Scientists, naturalists, and community members work together for a day to inventory a property and contribute to biodiversity knowledge. On October 1st, Upper Canada College Norval Outdoor School and rare Charitable Research Reserve held a BioBlitz event with the goal of engaging community members and finding as many species as possible on the beautiful Norval property.

Osprey- Photo by Leslie Abram

Now back to the event! The event kicked off at 6:00 am, and early bird participants arrived bundled-up after the first frost of the year. Some of our early participants were lucky enough to hear a great horned owl and an eastern screech-owl. Other early morning sightings include deer, osprey and a coyote! As the day warmed up, so did our sightings! More and more people arrived to contribute their eyes, ears, expertise and enthusiasm.

Searching for Benthic Invertebrates- Photo by Jenna Quinn

The event brought over 185 people together, including over 30 species experts with participants travelling from all over Ontario to help us search the property. Together we were able to identify 526 species, with over 33 observers using the iNaturalist app that we used to track observations. We found mainly plants, insects, and fungi, including a deadly mushroom species!

The data collected at this event will contribute to the knowledge of species diversity at the Norval property as well as the nature selfie that was taken of Canada this year.

As a nature lover, one of the best parts of the day was hearing what participants said as they came back from Guided Sessions. I love hearing people exclaim their interest in nature, biology, and conservation. An important part of conservation is education, which I believe is one of the greatest outcomes of Community BioBlitz events. I watched people of all ages come back with smiles from ear to ear and I felt a lot of hope that these people would carry this enthusiasm for nature into their daily lives. One student form UCC was especially engaged at the event:

“What a great way to spend a Sunday – discovering all sorts of flora and fauna at Norval! Thank you to the experts for teaching me to identify and document many species of plants and animals that I saw on the land, in the sky and in the water. The Bioblitz was a fabulous experience. It was a great to be outside with friends and family learning about what makes this land so unique!” Stephen Stack – Year 8 – Upper Canada College

This testimonial among many others is like music to my ears. Let’s hope that the many BioBlitz events that occurred across the country during this milestone year and in previous years have inspired the next generation to be environmental stewards and help protect biodiversity locally, nationally and internationally.

Insect identification- Photo by Norval Staff Member

Next year, rare will be participating in City Nature Challenge, where multiple urban areas will attempt to observe the most species over multiple days. If you are interested in participating in this event, keep an eye on the rare website in the New Year or subscribe to our mailing list here if you haven’t already.

If you would like more information about the BioBlitz Canada 150 events that happened this year, please visit:

Web Site

Trumpeter Swans at LaSalle Park

by Sandy Gillians

Members of the Halton/North Peel Naturalist Club

We had a great turnout for the birding/Trumpeter Swan outing on Saturday November 29th. A total of 14 hardy members and guests of the Halton/North Peel Naturalist Club managed to find each other at LaSalle Park in Burlington in spite of confusion over “which” parking lot we had agreed to meet at. Oops! Fortuitously, the carpoolers noticed a group of people gathered at the base of a tree looking up at what we learned later was an Eastern Screech Owl. Curious, we moved to join them and to our surprise they were our own members! Thanks, Mr. Owl – although I personally would have appreciated a sighting and not just rumour of your presence.

IMG_1606We spent a windy hour sighting waterbirds by the shore of Lake Ontario, including a Bald Eagle, Pied-billed Grebe, Common Golden Eye, Red-breasted Merganser, Canvasback, Scaups, Coots, and Buffleheads. I heard music playing somewhere in the distance, and it took me a minute to realize that it was the sound of Trumpeter Swans living up to their name, and not a brass band!

Harry Lumsden
Harry Lumsden

We then took the path along the shore of LaSalle Park to meet up with the remarkable Trumpeter Swans and their saviours – the volunteers of the Trumpeter Swan Restoration Group and Coalition. Over thirty years ago Harry Lumsden, a retired Ministry of Natural Resources biologist, made it his mission to bring the endangered Trumpeter Swans back to its traditional range in Ontario. Starting with just a few eggs, Harry and his volunteers have taken Trumpeter Swans in Ontario from extinct to a population of a thousand, the vast majority of which overwinter here in LaSalle Park. According to the Trumpeter Swan Coalition,

The harbour is perfectly situated to provide shelter from the cold north and easterly winds; it has a beach area where they can rest; there is an abundance of aquatic plants for them to feed on and the water is shallow enough near shore for them to tip to feed (they don’t dive).

Human encroachment around the Great Lakes, the draining of wetlands and development have practically eliminated suitable overwintering grounds for Trumpeters. Without LaSalle, they have nowhere to go.

Gotcha! Off to be tagged.
Gotcha! Off to be tagged.

Members of the restoration group – including Harry Lumsden himself – were on hand to answer questions. To our delight volunteers were feeding the swans in order to catch some of the cygnets that required tagging for identification purposes. As one of the world’s heaviest creatures capable of flight, even the youngsters made for a big armload.

On a more serious note, the Trumpeter Swan Coalition spoke with us and with other members of the public about their concern over a proposed marina expansion. The expansion, if it goes through, will overlap this small wintering area and alter the habitat. They have persuaded the Ministry of the Environment to require a higher level of environmental assessment and it is hoped that the needs of this fragile population will take a far higher priority than encroachment for purely recreational purposes. Read more about the issue here:

At this point several of our members called it a day, and new member Aaron Keating led a much smaller group to Sedgewick Park in Oakville. This small gem of a woodlot is frequented by interesting birds late into the fall and winter, and indeed we spotted an Orange-crowned Warbler, Northern Mockingbird, and Wilson’s Warbler among other species.

Our total count for the day was 33 species at LaSalle Park, and 5 species at Sedgewick Park.

It was a fun day out, and we’re looking forward to the next one which will be the Christmas Bird Count on December 27th.

Going Viral – The Real Way

by W.D. McIlveen –

All readers must surely have heard of the ongoing outbreak of the Ebola hemorrhagic fever that is occurring in several countries in West Africa. The disease is indeed a nasty one that starts with a fever, muscle pain, and headache followed by vomiting, diarrhea, and impaired kidney and liver function. Internal and external bleeding may also occur. The mortality rate of the current outbreak stands at about 70%. As of 14 October 2014, 9,216 suspected cases and 4,555 deaths had been reported. Given that the total population of the three main affected countries, Liberia, Sierra Leone, and Guinea, is over 22.1 million people, this translates to only 0.041% of the population infected. While this may seem to be a very small proportion, it must be realized that the number of people infected is continuing to increase.

Ebola hemorrhagic fever is caused by a virus. Among a large number of virus diseases affecting humans, there are some rather familiar types including AIDS, chickenpox, common cold, hepatitis, influenza, rabies, shingles, measles, SARS, West Nile fever, and yellow fever. Many of these have multiple strains. A virus is not a living organism though it does share some characteristics with pathogens of plants and animals. Instead, viruses are essentially sections of rogue DNA or RNA genetic material surrounded by a protein coating. They are capable of reproducing (increasing in number) by causing their host to make more copies of the virus, each one capable of causing the disease in the host.

All living species as well as viruses need to be able to reproduce themselves. If they don’t, then, over time, they will simply die out. If a species is to retain a stable population, then they need to replace themselves on a one for one basis. In the case of animals including humans, the female must, during her lifetime, produce two offspring (male and female on average) that live to reproduce themselves. Of course, not all offspring will survive to do so therefore the females must produce in excess of the minimum to compensate for the premature loss of the young. If she doesn’t, the species will die away. If she produces more than the number required to maintain the status quo, then the population will increase. This is simply a basic biological principle that often gets overlooked.

Figure 1. Examples of population growth curves for species reproducing at different rates.
Figure 1. Examples of population growth curves for species reproducing at different rates.

In general, a reproducing population will increase at rates in excess of the minimum. The rate of increase is much like the way one must pay interest on the portion of an unpaid loan or receives interest (albeit very low these days) on a bank account. The longer that such an account exists, the greater will be the amount of accrued interest. The same thing applies in biological systems and the data can be plotted mathematically in graphs (Fig. 1). The rate of increase, ‘r’, can vary widely. A plant for example may produce just a few seeds or may produce thousands of seeds each year. The larger the number of seeds that are produced, the faster that an unchecked population can grow. When a population of some species is growing at a high rate (e.g. a rate higher than we humans wish it to be), we reach epidemic or invasive proportions.

Figure 2. Graph showing the ‘s-shaped’ pattern of colonization of a suitable habitat by an introduced organism.
Figure 2. Graph showing the ‘s-shaped’ pattern of colonization of a suitable habitat by an introduced organism.

In reality, a species will typically increase until there is no more space available or all of the resources are used up (Fig. 2). Dandelions, for example, will spread in a newly cultivated field until there is no more space left in which a seed can germinate and grow into a new plant. Disease organisms such as potato blight will spread through the crop until it has infected all of the available host foliage. The same principle applies to all organisms – fungal, bacterial, viral, insect, mammal, etc. Populations simply cannot increase forever. As well as exhausting all available resources or space or hosts, other factors will often have a bearing on the situation for they too will become hosts for a different type of organism. For example, an infestation of caterpillars on a crop will be subjected their own set of parasites and hyper parasites that keeps the population in check. And it is never in the long-term interest of a parasite to kill all of its hosts.

In reality, not every seed will germinate, or the conditions for growth are not suitable, or the plant or whatever organism is itself subject to its own parasite. In a balanced natural system, the growth of populations of all types of biological entities is constrained and the system functions as nature intended. The problem comes when a particular species does not have its inherent control systems. This is usually the case (initially) for a newly introduced species and it reaches undesirable numbers. This applies to plants, insects, fungi, bacteria, viruses, etc. But the net effect of all the factors that may come into play are keeping the ‘r’ rate lower.

Now, in relatively recent times, the computer programmers needed a word to apply to situations when malicious software was introduced into the electronic communications used by functioning computers. They latched on to the term ‘virus’ from the field of biology for they considered the desirable programs running on the computer to be ‘infected’ by the undesirable software. They could have just as easily used the term ‘fungal’ or ‘bacterial’ or even ‘epidemic’ to indicate the ability of the software to spread to other computers. The application of the term ‘viral’ still remains incorrect. Even more recently, people have used the term ‘viral’ to indicate the rapid spread of a photo, film clip, or some type of information among cell phone users and the like. The use of the word in this way is quite different from that where the malicious software is involved. It is even more distant from the true meaning of ‘viral’ and its use should be discouraged. Hopefully, time will cause the term to become obsolete in this manner of use and that its use will return to where it truly belongs – restricted to the world of virologists that are dealing with the spread of real issues including infectious diseases such as Ebola.

Credit Valley Conservation Volunteers Honoured at Ontario Awards

Credit Valley Conservation award winners celebrate with a smile. (From left) CVC CAO Deborah Martin-Downs, Mississauga Volunteer Pat Kelly, MPP Dipika Damerla, Acton volunteer Bill McIlveen and CVC Volunteer Program Coordinator Annabel Krupp.

More than six million Ontarians contribute to their communities through volunteerism each year. In recognition of this, the Ontario Ministry of Citizenship and Immigration held a Volunteer Service Awards ceremony on April 29. The event celebrated the dedicated service of volunteers in the western GTA.

Credit Valley Conservation (CVC) nominated three volunteers for their outstanding contributions to the local environment. Mississauga’s Pat Kelly and Jean Williams along with Acton’s Bill McIlveen received awards for 10, 40 and 20 years of service respectively. Award recipients were presented with a commemorative pin and personalized certificate acknowledging their years of service.

“Volunteers serve such an important purpose at CVC and their support allows us to perform much-needed work in the community,” said Annabel Krupp, Volunteer Program Coordinator at CVC. “The ceremony showed that volunteer efforts do not go unnoticed.”

The ceremony, held at the Mississauga Convention Centre, was attended by hundreds, including MPP Dipika Dimerla and CVC CAO Deborah Martin-Downs.

The Ontario Volunteer Service Awards recognizes youth with over two years of continuous volunteer service and adults with over five years of continuous service. Nominees must be active participants in the organization and must not receive payment for their services.

Conservation Authorities are a provincial/municipal partnership. CVC was established by an Act of the Province of Ontario in 1954 with a mandate to protect all natural resources, other than minerals, in the area drained by the Credit River. We have been working for 60 years with our partner municipalities and stakeholders to protect and enhance the natural environment of the Credit River watershed for present and future generations. CVC is a member of Conservation Ontario.

Return of the Phosphorus : Algae Issue

by W.D. McIlveen

On February 27, 2014, the International Joint Commission [I.J.C., 2014] released a report on the most recent algae bloom problem in Lake Erie. That report had much in common with a similar problem that existed in the Great Lakes about 50 years before. That problem was the association between phosphorus loading in the water column and the subsequent growth of algae, most conspicuously Cladophora glomerata, though blue green bacteria and other species constitute additional problems.

Figure 1. Cladophora on shore of Lake Ontario at Lorne Park, Mississauga, 1969. Photo from Mississauga Public Library collection.
Figure 1. Cladophora on shore of Lake Ontario at Lorne Park, Mississauga, 1969. Photo from Mississauga Public Library collection.

Algae, like all aquatic organisms, are dependent upon the chemical constituent chemicals in the surrounding water. Generally, chemical concentrations in the water are quite dilute. As it turns out, the essential chemical that is most limiting for algal growth is phosphorus. As a result, small increments in the level of soluble phosphorus cause large responses in growth of the algae. When phosphorus levels in lake water increased up into the 1960s, excessive growth of algae occurred in the Great Lakes. The algae washed up on the shores of the lake (Figs. 1 and 2) where it began to decay and caused very unpleasant odors. Decaying algae consumes oxygen and when this happens in the aquatic environment, the eutrophic conditions with insufficient oxygen become limiting to many organisms including fish.

Figure 2. Cladophora on shore of western Lake Ontario 1969. Photo by W.D. McIlveen
Figure 2. Cladophora on shore of western Lake Ontario 1969. Photo by W.D. McIlveen

There were many sources of the phosphorus, however, the prime source was attributed to detergents used by human residents around the lakes [Schindler, 2008]. Despite fierce resistance from the soap and detergent industry, they were forced to remove the phosphate-based chemicals from their product by 1972. Following this, phosphorus levels in the water gradually declined and the algae problem generally improved. The removal of phosphorus from detergents did not permanently solve the problem. There was year to year variation in algae growth and the problem appeared in years of heavy growth (Fig. 3).

Figure 3. Cladophora on shore of Lake Ontario at Jack Darling Park, Mississauga, Sept. 11, 2011. Photo by W.D. McIlveen
Figure 3. Cladophora on shore of Lake Ontario at Jack Darling Park, Mississauga, Sept. 11, 2011. Photo by W.D. McIlveen

Over time, the human population around the lakes increased further. Other sources of phosphorus grew including releases from sewage treatment plants. As well, new complicating factors appeared. Global warming caused earlier warming of the near-shore waters with the result that alga populations could become established earlier in the Spring. The appearance of the Zebra (Dreissena polymorpha) and then Quagga (Dreissena bugensis) Mussels made major changes in water quality. These species filter huge quantities of water with the result that water is made clear. With clearer water, light could penetrate to greater depths and this effectively extended the area over which the algae could attach and grow. More growth means more problems. Other introduced species such as the Round Goby (Neogobius melanostomus) and large populations of waterfowl that now feed on the mussels further complicate the picture.

In Lake Ontario, the water current in the western portion of the lake is generally counter clockwise when seen from above. This means that the currents along the shoreline off Peel and Halton are from east to west. The Halton shoreline is therefore downstream from any sources of phosphorus in Peel and the City of Toronto. In addition, the nature of the shoreline with piers and other structures influence the movement of the water and can cause floating algae to become trapped. Winds and storms can deposit, and remove, algae on the shore where it is an unwelcome caller in the minds of local residents.

The recent report by the IJC [IJC, 2014] has concluded that the most recent problem of algae in Lake Erie was mainly due to agriculture. This includes large animal production facilities and heavy use of fertilizers for crop production around the Lake. As well, residential use of fertilizers for lawns and gardens contribute a significant amount of phosphorus. The latter source was also confirmed in studies completed in Halton [Aquafor Beech, 2006]. These sources need to be addressed or the eutrophication problem will persist and grow. It is still too early to know what measures will be undertaken in coming years. Phosphate-free lawn fertilizer may be mandated for home-use for example. Conditions around Lake Erie must be altered or the algae issue will continue and grow. The so-called ‘dead lake’ state could return even though eutrophication actually represents a hyper-lively water body.

References Cited:

Aquafor Beech Limited. 2005. Final report prepared for Conservation Halton LOSAAC Water Quality Study. 127 pp.

International Joint Commission. 2014. A Balanced Diet for Lake Erie: Reducing Phosphorus Loadings and Harmful Algal Blooms. Report of the Lake Erie Ecosystem Priority. 100 pp.

Schindler, D.W. and J.J. Vallentyne. 2008. The Algal Bowl – Overfertilization of the World’s Freshwaters and Estuaries. University of Alberta Press, Edmonton. 323 pp.

One Step Forward, One Step Back – Recent Changes in Invasive Species

by W.D. McIlveen

Figure 1. Adult Hypena opulenta
Figure 1. Adult Hypena opulenta

The situation regarding invasive species is never static. Periodically we get good news mixed in with the gloomy reports of some new species that has appeared at our door. And so it is that we have some recent changes in local matters pertaining to invasive alien species.

Starting with the bad news first, the Asian Longhorn Beetle (Anoplophora glabripennis) which attacks a wide range of tree hosts had been declared eradicated from the Cities of Toronto and Vaughn. By 2003, the beetle had established a modest area of infestation in the boundary area between those municipalities. An intensive program was launched to eliminate the infestation by cutting and destroying all of the host trees within a 400 metre radius of the infestation. After detailed surveys of the area had found no more indications of the beetle for a period of five years, the pest was declared eradicated by the Canadian Food Inspection Agency (CFIA) on April 5, 2013. Unfortunately, a new infestation was detected in an industrial area on American Drive near Pearson International Airport in Mississauga on September 20, 2013. It is not known if the two areas of infestation are connected. They are not located too far apart so a connection cannot be ruled out though a new source of infestation is presumed. Multiple points of infestation are known at other locations in North America where similar eradication programs had been carried out. Some trees have already been cut down and it is expected that a similar form of eradication program will be undertaken to insure that the beetles do not spread.

Figure 2. Larva of Hypena opulenta
Figure 2. Larva of Hypena opulenta

On August 23, 2013, Credit Valley Conservation (CVC) reported that two round gobies (Neogobius melanostomus) were caught in the west Credit River at Hillsburgh. Additional surveys found at least 50 more of the fish just downstream. Previously, the species had been found only at sites in the catchment area where the water was closely connected to Lake Ontario, a location where the species has become well – established. It seems improbable that the fish had made it to Hillsburgh across dams and other obstacles without some sort of human intervention, whether intentionally or unintentionally. A program to manage the problem species needs to be developed in concert with MNR, CVC, local land owners and other stakeholders.

Not all news concerning invasive species is bad. In 2006, moth larvae were found feeding on swallow-worts in southern Ukraine. The larvae were brought to the Commonwealth Agricultural Bureau International (CABI), a highly recognized facility that studies biological control agents, in Switzerland for rearing and initial testing. The moths were found to be host-specific and very effective in controlling the host plant. Additional testing was done at the control facility at the University of Rhode Island to verify the results. The tests were so successful that the University petitioned the U.S. Department of Agriculture in 2012 to allow for the release of the moth to control the Swallow-wort problem. The US still requires one additional step before approval is granted but that approval appears to be easily achievable (after the current political financial situation is resolved in that country). The application though has met all of the conditions set by Canada concerning the release of a biological control agent. As a result, 500 of the moth larvae were released at infested sites near Ottawa. So far, the caterpillars appear to be surviving well and the populations are being monitored. In time, it is not unreasonable to expect to see the moths make their way to our area. While there are many areas in the Province where Swallow-worts are a problem, there are many places around Toronto (e.g. Don River Valley) where the populations are very dense. The moth is known as Hypena opulenta (Figure 10). It resembles a few other Hypena species that occur in our area; however, those other species do not feed on Swallow-wort. This similarity and any resulting confusion may hinder the monitoring of the spread of the species into our area but the presence of the distinctive caterpillars (Figure 2) feeding on the plants should be easy enough. Naturalists should be on the lookout for these caterpillars wherever the Swallow-wort is present though it may take several years to reach here on its own.

Death of a tree

Two weeks ago one of my favourite trees was felled by a bulldozer. This tree, on Creditview Rd. in Brampton, was graced with the lovely arching form that only mature elms exhibit.

Before Dutch elm disease ravaged the land this beauty was common. The few remaining mature elms are rare treasures.

The lure of this elm was so powerful that I would include Creditview Road on my route to work simply to see it in the morning. The green and gold cropland surrounding it provided a lovely foil for its iconic form.

The cropland is no more. The soil that gave life to the wheat, the corn and the soybeans has been scraped bare by earth moving equipment. Denuded and sterilized, the land waits sullenly for the homes and strip malls that characterize the inexorable expansion of Brampton.

I knew the destruction of this landscape was imminent. New development announces itself with cheery signs and property stakes. But I harboured hope for the elm. Fencing had been placed around it. I thought – naively it turned out – that “my” elm would be saved.

The elm now lies ingloriously in the mud, its roots ripped from the desolate earth.

I realize that thousands of trees are felled every day in this province to feed various appetites. I realize as well that landowners have certain broad rights to do as they wish with the property they own.

But, perhaps it is time to try to enshrine some protection for trees of character – trees that rate highly for certain features including size, rarity, cultural importance and the admittedly subjective quality of beauty.

The elm will continue to influence the route I take to work. I’ll now avoid the place where it once stood.

by Don Scallen
Vice-President, Halton/North Peel Naturalist Club

Tufa deposits discovered in Credit River watershed

Belfountain CA Tufa Deposit (Photo by Lynda Ruegg)
Belfountain CA Tufa Deposit (Photo by Lynda Ruegg)

In 2012, Credit Valley Conservation inventory staff discovered a provincially and nationally rare phenomenon along the Niagara Escarpment at Silver Creek and Belfountain. This discovery was of tufa, a soft rock, being actively formed at the emergence of select springs. Tufa is a variety of limestone. It differs from typical Escarpment rock formed on ancient sea beds from calcium-rich shells, exoskeletons and coral. Instead, tufa is formed by calcium precipitated out of water. Bits of the precipitated calcium carbonate can amalgamate to create larger rocks.

Ontario’s known tufa deposits are formed at springs and waterfalls, particularly along the Niagara Escarpment. Tufa is only known in Ontario from Brantford, Paris, Dundas, Niagara Falls, and with the discoveries reported herein, Silver Creek and Belfountain. In 2008, the Ontario Ministry of Natural Resources designated a tufa deposit in Brantford as a provincially significant Earth Science Area of Natural and Scientific Interest.

Tufa only forms at springs where just the right conditions exist. First, ground water must contain carbon dioxide picked up from the air, making the water weakly acidic. Second, the ground water must become supersaturated with soluble calcium by dissolving limestone. Third, as the calcium-rich water emerges from the ground, it must release enough carbon dioxide to cause the soluble calcium to solidify into insoluble calcium (rock). The same precipitation process is responsible for the formation of stalactites and stalagmites in caves.

Precipitated Calcium Carbonate in Tufa Pool at Silver Creek Conservation Area (Photo by Leanne Wallis)
Precipitated Calcium Carbonate in Tufa Pool at Silver Creek Conservation Area (Photo by Leanne Wallis)

Tufa was first found in the Credit River watershed by the author and assistant Pete Davis at Silver Creek Conservation Area. The author recognized it based on tufa deposits seen on a Hamilton Naturalist’s Club hike to Spencer’s Gorge (Dundas) led by Dr. Terry Carleton, a forestry professor at the University of Toronto. Dr. Carleton was the first to document tufa deposits at Spencer’s Gorge, which he recognized based on his observations of similar occurrences in England. News of the discovery at Silver Creek led to CVC’s Scott Sampson reporting possible tufa at Belfountain Conservation Area. A visit by the author, CVC’s Dawn Renfrew, biologist Lynda Ruegg, and Dr. Carleton confirmed the report.

Tufa deposits at Belfountain may be more abundant than anywhere else in Ontario. Tufa deposits can be easily observed at this conservation area on north-facing slopes. The best viewing spot is from the foot bridge that spans the West Credit River. The largest and most impressive tufa deposit can be seen from here on the slope on the south side of the river. This tufa deposit is almost completely covered by a blanket of moss in shades of green and red, with a small patch of whitish tufa peeking through.

Tufa deposits are a challenging growth environment for plants because soil is absent, the substrate is rock, conditions are calcareous, and there is a constant flow of cold water. Few plants can function in such environments; many of those that can are mosses, especially those specializing in seepy, calcareous habitat. Our tufa deposits, if not barren, tend to be either dominated by mosses, or populated by hardy plants such as Watercress (Nasturtium sp.), Jewelweed (Impatiens sp.) and European Coltsfoot (Tussilago farfara). The dominant moss on Silver Creek and Belfountain tufa deposits is Cratoneuron filicinum. It is not a rare moss, however, there are some provincially rare mosses known to grow on tufa that could be found in future inventories. Interestingly, because photosynthetic activity removes carbon dioxide from the spring water, mosses and other plants actually help create more rock once they become established.

In addition to potentially supporting rare mosses, tufa formation areas may also act as amphibian and dragonfly/damselfly breeding habitat. This is because tufa is often formed on slopes, creating terraces on which small pools of water are formed. Evidence suggests that salamanders (some of which are Species At Risk) may breed in these pools, and as some dragonfly/damselfly species restrict their breeding areas to seeps, they may also be found in these tufa pools. These spring-fed pools may also be an important water source for wildlife, especially if they remain unfrozen in winter months.

Tufa formation is a topic only recently receiving attention amongst biologists, and with increased awareness, the author expects more tufa deposits to be found in the future along the Niagara Escarpment.

Leanne Wallis
Credit Valley Conservation