A day in the life of CVC’s Terrestrial Monitoring Crew

Terrestrial monitoring crew member stuck in the mud

The crew ID's grass at Rattray Marsh

The terrestrial monitoring specialist measuring a wetland transect

7:00 a.m. We meet early at the office to beat the summer heat and drive North.

7:30 a.m. Still driving. The scenery is gorgeous as the road has begun to wind through the Escarpment.

7:50 a.m. Squeezed into chest waders, we walk into our site and mutter: “Do we have the field guides? Check. Measuring tape? Where is that…”

8:10 a.m. An easy start through a wet meadow quickly turns into a challenge as the water gets deeper: usually one of us gets stuck. After a fit of laughter and pulling on both arms, we continue onward.

8:25 a.m. Finally we come out into the open where hummocks of grasses and sedges peak above the water. Our first site marker shimmers out to us like a beacon - we did not get lost today!

8:30 a.m. Taking turns wading in the water, we begin our first vegetation survey. Within one square meter, we identify everything green and assess the relative abundance of each species growing there. We work our way along our transect towards the upland forest. Every 10m, we do a plant survey.

9:30 a.m. Moving out of the open water, grasses and sedges are becoming more thick. We look around to see what herbaceous plants are flowering –a few blue flag irises are always beautiful to see. Suddenly, we hear a grumbling; time for second breakfast.

10:00 a.m. The water level has dropped to our ankles and we are twisting our way through the branches of a dogwood thicket. Hardly anything grows in under their shade.

10:30 a.m. Always HOT, around 30 degrees celsius, especially in rubber chest waders.

11:50 a.m. Tummies rumbling, again. I realize that a tomato sandwich doesn’t keep very well in the heat – tupperware can turn into pressure cookers.

12:30 a.m. Hmmmm….what plant is this?! Exciting and challenging, we use the dichotomous key in our field guide to identify the unknown plant. Anything we don’t know, we take a full plant sample and bag for later

1:40 p.m. Under a canopy of trees, we are at end of our transect. There is a completely different suite of plants growing here. Lots of jewelweed around with patches of sensitive fern.

1:50 p.m. The humming begins – the mosquitoes have found us!

2:14 p.m. Ooooh la la!!! We find one lone swamp white oak - a rare tree in our Watershed and the Region of Peel!

2:20 p.m. Survey complete and we follow our path out. Once we reach our vehicle, we are relieved to squeeze out of our sticky chest waders and race to turn on the air-conditioning.

3:10 p.m. Back at the office, we identify today’s unknown plants, prepare tomorrow’s site visit and bid farwell, “see you tomorrow, bright and squirrelly!”

Under the Naturalists' Eye: Why some trees lose their leaves in the winter?

Some trees with broad leaves, such as maple, ash, and elm, lose their leaves every winter. Most of these trees live in temperate regions, where summers are warm and winters are cool. These trees are called deciduous trees from the Latin word decidere meaning “to fall”. There are three main reasons that trees lose their leaves.

1. Freezing Temperatures
The first is that while a tree’s roots, trunk, and branches can endure freezing temperatures, the leaves of these trees cannot. Leaves are made up of cells that are filled with sap, which will freeze when the temperature drops below zero. The additional weight of frozen leaves would make a tree much more likely to suffer branch breakage from ice and snow buildup. To prevent this damage from occurring, the growth of a special layer of cells, called the abscission zone, eventually cuts off the leaf’s food and water supply. The tree then seals the cut, so that when the leaf is finally blown off by the wind, or falls from its own weight, a leaf scar is left behind.

2. Decreasing Sunlight
The second reason that leaves fall relates to the amount of sunlight available to the tree (photoperiod). Trees feed themselves through a process called photosynthesis. During this process, the cells in the leaf use the sun’s energy, water and carbon dioxide to create oxygen and simple sugars (carbohydrates). As the sunlight decreases in the autumn, the amount of energy the leaves are producing can be less than the amount of energy required to maintain them. A pigment in the leaves, called phytochrome, senses the decreasing photoperiod (the fact that the nights are lengthening), and triggers the leaves to fall from the tree.

3. Lack of Water
The third reason that leaves fall is related to decreasing temperatures and a lack of water. During the process of photosynthesis, plants transpire. Transpiration, or the evaporation of water from plants, mainly occurs in the leaves. Trees need a source of precipitation in order to replace the water they lose. In the winter, most precipitation comes in the form of ice and snow, non-liquid forms of water that are inaccessible to the tree. As temperatures begin to decline in the fall, trees (and other plants) will prepare for the approaching period of drought by moving their nutrients below the ground to their roots.

Summer Thunderstorms

This year the number of days reaching 30 degrees, for the months of June, July, and August, throughout the province, exceeded those of 2004 by a wide margin. Despite this warming trend, a number of thunderstorm cells were observed throughout the watershed this summer. Many of these events were responsible for property damage in certain areas, particularly along Cooksville Creek near Paisley Boulevard and more recently Mill Creek at Townline Road. Historically, extensive flooding in the Credit River Watershed has been limited. Major flooding events (i.e. Hurricane Hazel in October, 1954 and the storm in May, 1974) have caused some property damage in certain low-lying “floodplain” towns and villages. However, in general, flood damage due to rainfall related events has not been a common occurrence in this watershed.

Sediment wash-off along Townline Road in the Town of Orangeville.

Many of the events observed over the summer months were of an extreme nature, very localized, covering a small area, and with a relatively high rainfall intensity. Two prominent storms that occurred on August 2nd and August 19, resulted in flash flooding and extensive damage . Damage resulting from the August 2nd storm event primarily attributed to nuisance flooding. (i.e. heavy erosion, tree or brush washout and basement flooding). However, reports also indicated that heavy rains, lightning and winds during this period may have also contributed to the crash of Air France Airbus A340 landing in Toronto. The event which passed through the south-west end of the watershed within the City of Mississauga was reported to have a magnitude equivalent to a 2 to 5-year event and in some instances was equivalent to a 25-year event.

On August 19th 2005 a storm passed through the north end of the watershed. According to CVC Rain Gauges the storm had a magnitude equivalent to a 10-year event. Damage attributed to this event included sediment wash off and road overtopping. Impacts from this storm were also felt on an adjacent watershed, which included the washout of the Finch Ave. bridge in Toronto.

Wash-out of the Finch Avenue Bridge in Toronto.

Environment Canada, has listed Ontario as the province with the highest number of thunderstorm events. Canada’s climate is one of extremes and with the advent of climate change these extremes (droughts and floods) will become more and more frequent. Current trends and forecasts indicate that storm events are not only becoming more frequent, but are also becoming more intense. This intensity is attributed to the fact that more multi-celled storm systems are moving through our region versus single-celled storm events. Current practice for designing water resources infrastructure only looks at single-event storms. CVC will be undertaking an initiative to examine how these storms vary in both space and time over the watershed and what impact they pose on the Credit River and its tributaries. This approach is a more realistic representation of the climatic conditions we are currently observing and will allow us to better manage our watershed and help protect our communities.