The Bruce Beckoned

The Bruce Beckoned

Ontario Nature’s 85th annual gathering

Story by Inga Hinnerichsen

Ontario Nature celebrated its 85th anniversary combined with its Annual Gathering on the weekend of June 3, 4 and 5, 2016. The organisation was founded in 1931, then called the Federation of Ontario Naturalists. Today Ontario Nature has over 150 member groups, such as Norfolk Field Naturalists, all throughout this province. Together we share the love of nature and continue to work towards preserving natural areas, flora and fauna for future generations.

The NFN participated with a small delegation: Bernie Solymár, Len Grincevicius, Diane Salter, Karin Jonasson, David Curry and Inga Hinnerichsen. On the way we stopped at Sauble Beach to observe a few rare Piping Plovers that were nesting on the beach. Sadly, later news told us that none of the nests this year were successful. Some were destroyed by high water and waves, others fell prey to gulls and other predators. All participants, Ontario Nature and member club delegates, numbering well over 100, were staying at Evergreen Resort, a family-owned facility on the shores of Lake Huron. The resort features a rambling main lodge with a spacious lounge and dining room overlooking the bay, a games room, tennis court and heated swimming pool provide recreational opportunities for guests. Small cabins and a campsites are scattered in the surrounding woods.

Ontario Nature had gone to great lengths organizing the weekend. Beside the AGM there were a variety of activities, lectures and outings to choose from: Early Morning Birding, Exploring Forests and Wildflowers, Herpetofauna, Spiders and various natural environments in the area. You could also choose from a variety of indoor presentations on many interesting topics. The Evergreen Resort provided a wide range of breakfast choices, a scrumptious snack buffet and tasty dinners. We got bag lunches to take along on our outings.

One day we had the opportunity to visit one of NCC’s properties in the area. This weekend also coincided with the Bruce Peninsula Orchid Fest. Our group participated in a guided tour of the local environment famous for these exotic flowers and many other species typical for the alvars. The Bruce Peninsula is the northern extension of the Niagara escarpment. The following are excerpts from Wikipedia dealing with the ecological characteristics, geography and geology of this formation.

The Niagara Escarpment stretches 725 kilometres from Lake Ontario to the tip of the Bruce Peninsula between Georgian Bay and Lake Huron. The Niagara Escarpment represents the largest contiguous stretch of primarily forested land in south-central Ontario. It includes the greatest topographic variability in southern Ontario, with habitats ranging over more than 430 metres in elevations and including Great Lakes coastlines, cliff edges, talus slopes, wetlands, woodlands, rare limestone alvar pavements, oak savannahs, conifer swamps and many others. These habitats collectively boast the highest level of species diversity among Canadian biosphere reserves, including more than 300 bird species, 55 mammals, 36 reptiles and amphibians, 90 fish and 100 varieties of special interest flora.

Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO 3 ).

About 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to many erosional landforms. These include limestone pavements, pot holes, cenotes, caves and gorges. Such erosion landscapes are known as karsts, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. Bands of limestone emerge from the Earth’s surface in often spectacular rocky outcrops and islands, such as the Niagara Escarpment.

An alvar is a biological environment based on a limestone plain with thin or no soil and, as a result, sparse grassland vegetation. Often flooded in the spring, and affected by drought in midsummer, alvars support a distinctive group of prairie-like plants. Most alvars occur either in northern Europe or around the Great Lakes in North America.

This stressed habitat supports a community of rare plants and animals, including species more commonly found on prairie grasslands. Lichen and mosses are common species. Trees and bushes are absent or severely stunted.

The primary cause of alvars is the shallow exposed bedrock. Flooding and drought add to the stress of the site and prevent many species from growing. Crevices in the limestone provide a distinctive habitat which is somewhat protected and may provide habitat for unusual ferns. Bare rock flats provide areas with extremely low competition that serve as refugia for weak competitors such as lichens and mosses. Depending on the depth of the soil coverage the Ontario alvars form tall grassy meadows, low grassy meadows, dry grassland, rock margin grassland and bare rock flats.

In North America, alvars provide habitat for birds such as bobolinks, eastern meadowlarks, upland sandpipers, eastern towhees, brown thrashers and loggerhead shrikes whose habitat is declining elsewhere. Rare plants include Kalm’s Lobelia (Lobelia kalmii), Pringle’s Aster, Juniper Sedge (Carex juniperorum), Lakeside Daisy (Hymenoxys acaulis), Ram’s-head Lady’s-slipper (Cypripedium arietinum) and Dwarf Lake Iris (Iris lacustris). Also associated with alvars are rare butterflies and snails.

The use of the word “alvar” to refer to this type of environment originated in Scandinavia. The largest alvar in Europe is located on the Swedish island of Öland.

Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO 3 ) 2 . It is resistant to erosion and can either contain bedded layers or be unbedded. It is less soluble than limestone in weakly acidic groundwater, but it can still develop solution features over time.

Dolostone can act as an oil and natural gas reservoir. An overlying layer of dolostone on top of limestone can act as a cap more resistant to erosion resulting in features such as Niagara falls.

Intrigued by the geology of the Niagara Escarpment? See Wikipedia for much more information.