A hike in Glendon: report on trail and riverbank state.

On a frizzing and wet Wednesday afternoon (about -2°C), precisely on November 23rd, we decided to take the shuttle bus to Glendon campus to take some photographs for the blogpost assignment. We were assigned both segment 4 of the Don’s riverbank and the state of the trail. We began by the trail and here are some of the photographs we got:

img-20161128-wa0027

Above we can see that the trail is made with muddy soil (it had rained and snowed a few days before), in a fairly good shape, with bare trees and smaller plants bording it, we can recognize Canada thistle (invasive species) and tall goldenrod (native, good point here). Some dead barks can be seen outside the trail, but they do not cross it. The number of different species present here seems to be quite high.

img-20161128-wa0024

Above, a lots of fallen leaves are present but not on the trail. We notice the presence of a non-identified species of bush with red wood, and a little individual of a pince species.

img-20161128-wa0022

On this part of the trail (above and below) small vegetation are practically inexistent. Only trees are present bordering the trail. A lot of fallen leaves cover the ground but the trail itself is still clear of it. The trail is bordered by rocks, maybe to delimitate it and prevent its degradation.

img_20161123_141612

Below the leaves are also present on the trait, and the plant species richness is poorer. We can recognize among the fallen leaves oak and maple species.

img-20161128-wa0020

Below the trail changes: it is not made of ground, it looks more like a road than a trail. Notice the presence of a garbage bin to encourage people not throw their litter on the ground. The litlle vegetation that we could see in the previous photographes are inexistent here, close to the road there is no small plants, probably a result of frequent passage of motorized vehicles, since it is more a road than anything else at this point.

img_20161123_151546

Afterwards we went to segment 4 of the riverbank, where we took these photographs:

img_20161123_152203img_20161123_152209img_20161123_152228img-20161128-wa0016img-20161128-wa0030

We can see some dog-strangling vine, and trees that according to the aspect of the leaves might be black cherries, a native species said to be very important to forest wildlife because of its fruit (but not for the humans because the cherries apparently are edible but with a harsh bitterness).

The rivebanks themselves are not equal: we can see that the side where we took the photographs from is more elevated and contains more vegetation than the other side, which is only made of mud and really flat, with some dead barks lying across it. We can hypothesized that trees and plants on our side of the banks are a good way to help stabilizing the riverbank and prevent the erosion. Indeed, according by a Watershed Restoration Project Report made in 1995 in British Columbia, the use of plants to stailize riverbanks is centuries old. They also precised that to prevent soil erosion, covering method is used by using a lots of plants such as grasses and herbs per unit areas, and that a structure made only by living material can improve slope stability. Materials such as timber, concrete, rocks and dead branches can be used as support constructions if plants and trees are not enough. Using living materials have also several advantages that the author of the report listed:

– protection against surface erosion;
– an increase of slope stability by root reinforcement and draining of the soil;
– protection against rock fall and wind
– regulation of temperature and humidity close to the surface, thus promoting growth
– improvement of the soil water regime via interception, evapotranspiration and storage
– soil improvement and top soil formation
– improvement of and provision for habitat
The last two are not the most necessary but do have a point though:
-structures fit into the landscape
-landscape is more appealing
The role of plants to improve riverbank stability and prevent erosion is established. But they also are shelters and food resources to huge amount of animal species that participate in enhancing the biodiversity of the area.
In Glendon we saw that a lot of invasive species are present like dog-strangling vine or Canada thistle that threaten native species. On this campus, according to an article published by The Globe and Mail, “blocks of quarried armour stone have been installed to preserve the Don’s eroding banks, weakened by all the urban rainwater and sewage overflow funnelled down into the city’s valleys, […] providing warm spaces and hibernaculums for butterflies and snakes.”
There still are works to do in Glendon campus against invasive species and soil erosion, but we might get there one day…
References:

Ontario’s tree atlas

The Globe and Mail’s article

Claire Hoarau

Advertisements
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s