Last week of stewardship

Here we are, the last stewardship session at Riverdale for this summer. We finished the season tonight by tagging invasive trees such as Manitoba Maple, Norway Maple, Black Locust and Tree of Heaven.

We put orange ribbons to mark those trees.
City workers will come to remove them. They won't remove them all but they'll decide which ones they can get rid of.

We had a pretty good turnout for the last week and some other stewards continued to remove invasive species. I must say that we haven't been able to kill all the DSV but we sure tried our best. It will be back next year but with some luck, there won't be as much. One can only be optimistic.

Cheryl found this interesting looking "thing" that was attached to the leaves of a sumach. Is anybody out there able to identify this? I apologize for the poor picture but it was getting pretty dark when I took this.

This one is not much better but maybe it can help.

Working at the site has been a lot of work but we also had much fun. I feel a little bit sad that it is now over but I'm hoping to see some of my co-stewards at one of the many planting events organized by Green Toronto this fall.

Studying Benthic Invertebrates

Note: this is a cross-posting from Don Watcher. I am repeating the posting here because it happened at Riverdale Farm Ponds.


A collection of clips from the Benthic Invertebrate study at Riverdale Farm Ponds

This week I went by Riverdale Farm Ponds to participate in a study to monitor pond organisms. The point of the study was to collect benthic invertebrates from the bottom of the pond. Benthic invertebrates are a group of creatures that live in an aquatic environment and include fully developed insects; insects in a larval stage; some crustaceans; and worms and leeches. Benthic Invertebrates can be used to measure the health of a pond. Since some species are more tolerant of pollution, the presence or absence of them can be used as a general water quality gauge.

The collection process involved donning hip waders, wading into the pond and collecting samples from the bottom muck with a special scooping net. Once the samples were collected, we went up to one of the buildings and sifted through the debris looking for different creatures. During our investigation we encountered aquatic sow bugs, midges, aquatic worms, scuds, leeches, and snails. All of these are mostly pollution tolerant and the species found indicated that water quality was low, about 7 on a scale of 10 (1=pristine water, 10=absence of life).

However, there is some good news. Last year an aerator was installed to inject air into the water. Due to several longterm problems, the ponds suffer from anoxic conditions which means that not much can survive here. A similar study was done before the aerator was activated and a grand total of 8 creatures were found. This year between 50-100 organisms were found. So things are looking up for the ponds.


Nathalie and Heather from Citizens' Environment Watch help facilitate the collection process


Looking for bugs in mud


A closer inspection reveals...


...a blurry image of a bloodworm

Benthic invertebrates revisited

This coming Tuesday, August 21, the Riverdale team will be participating in another session of benthic macroinvertebrates (aquatic) testing in the sanctuary pond. This is a monitoring study which involves taking samples from the pond and collecting insects from these samples. The benthic zone is the lowest level of a body of water. It is inhabited by organisms that live in close relationship with the ground, called benthos or benthic organisms.

Once again, we will work with members of Citizens' Environmental Watch, a community-based ecological group which organizes monitoring and stewardship programs. They use benthic invertebrates or "water bugs" as biological indicators to assess water quality. In order to collect these samples, we will have to get into the pond wearing hip waders and using nets to try to pick up as many "bugs" as possible.

Volunteers collecting specimens

Looking for signs of life

Wet weather

Last night, we worked in a different spot (at least, I had never worked there). We went on the right side of the sanctuary pond where invasives are having a field day. Aynsley told me that she did some planting there a few years ago but it now needs a lot of work. There is so much stuff, we could be working there until the end of the season. It's full of japanese knotweed and there is also grapevine, which is native but extremely invasive.


The pond is a great environment for the grapevine but there is really too much of it.

The weather was uncertain at the beginning of the evening but we decided to go on anyway. After about an hour, we had to stop because it was really coming down. Still, we had 5 brave souls who showed up.


We saw these ducks but couldn't identify them. They may be just mallards. (We keep hoping we'll see the wood ducks we spotted at the beginning of the season).

Hot night

The weather was hot tonight for the stewardship but 6 people showed up nevertheless. Cheryl suggested we only work for an hour and nobody argued with that. In addition to the pollination study (stay tuned for a post on that coming soon) and the watering, we went on a hunt for more DSV killing (we'll never get rid of that stuff but we sure keep trying).


A steward (who asked to remain anonymous) on the lookout for DSV


There is still quite a bit and it's getting harder to reach.


Still, I managed to get rid of some of it.


Another black crowned night heron (or maybe it's the same one
as a few weeks ago). It's still too far, I need Marnie's camera from
Beechwood Wetland.

At the beginning of the evening, we saw a juvenile night heron,
He was standing very close to the edge of the pond but he flew away
before I had a chance to take a picture. I haven't seen them coming
that close yet. We think that they are probably nesting nearby.

The New Enemy

Ok, I thought the worst invasive was Dog-strangling Vine but now, I know another one even worse. In addition, this one can also hurt you. If you brush against it, it burns like hell. In fact, one of its nickname is Devil's Claw. What is it? Any guesses? Why, stinging nettle of course. The Riverdale site has its fair share of this dangerous and even poisonous invasive.


Julia from the stewardship team works hard
on the stinging nettle.

Meanwhile, I was removing one my old favourites:
Canada Thistle

Now you see it...


Now you don't!

The best part of the evening was when we saw a night heron.

Black-crowned Night Heron

Duck sighting

This week we continued to attack the DSV slope. We're almost finished now so we should be able to focus on something else. At the beginning of the evening, I took some pictures of a couple of black ducks (or at least I was told that's what they are). If anybody knows different, please let me know.


Iris Versicolor

We also went to check on the planting we did last week. On the west side of the pond, there is a little island where some people planted irises and sedges. All the plants are doing quite well.




Sedges