STANLEY PARK NOTEBOOK
/by Jacqui Birchall
(click images to enlarge)
THE LOST LAGOON ALGAE
Seasonal and Unpreventable
Many people are concerned about the algae floating in Lost Lagoon. Stanley Park Ecology (SPE) provided the following information. One should remember that Lost Lagoon was previously a tidal mud flat that, many years ago, was enclosed by the Stanley Park Causeway. Fresh water was introduced, and it was hoped it would become a fisher’s paradise. There has been discussion by the park board, researchers, and others, to make it tidal again. Salt water would radically change the ecology and wildlife in the Lagoon. Beavers, for instance, are freshwater inhabitants. The remedy is not an easy one.
The algae is particularly dense at the north end of the lagoon, but parts of the lagoon are algae-free at this time.
TWEJ: How would you describe the algae blooms in Lost Lagoon this year, relative to previous years?
Algae on the north side of the lagoon. (Lagoon photos by jacqui birchall)
SPE: Stanley Park Ecology has not monitored the extent of algae blooms in previous years, so it's difficult to definitively or quantitatively say if the algae that has formed in the lagoon so far this year is comparable, or different from algae growth in previous years.
WEJ: What causes the algae blooms?
SPE: Multiple factors play into the formation of algae. Environmental conditions for algae growth require high nutrient levels, lots of sunlight, warm temperatures, and stable conditions. Although algae blooms can occur anytime of the year, they most often occur during the summer when there is abundant sunlight and hot weather, creating ideal conditions for plant and algae growth.
Lost Lagoon is a shallow, artificially created water body with little to no water flow. Additionally, the abundance of waterfowl in Lost Lagoon throughout the year contributes to the high concentrations of organic nutrients (through fecal matter) that continue to build up over time, creating a highly eutrophic freshwater system. These are perfect conditions for algae growth.
TWEJ: Is there anything that can be done to manage it/limit it?
SPE: Although it is virtually impossible to stop algae growth because it is a natural process, it can be limited by controlling the factors which cause it: light, temperature, nutrients, mixing/flow.
the bloom clears up mid-lagoon.
Unfortunately, in Lost Lagoon, limiting any of the above factors would be extremely difficult and require a large-scale intervention. The algae will naturally begin to disperse through the fall, as wind, rain, and lower temperatures flush out the stagnant water column.
TWEJ: Would reconnecting Lost Lagoon to the ocean, re-establishing it as an actual lagoon, help address the algae issue and have any other positive effects on the ecology of the pond?
SPE: Reconnecting Lost Lagoon to Coal Harbour would be an ecologically and logistically complex, large-scale intervention that would likely have major impacts on the existing ecosystem. Stanley Park Ecology has not conducted any studies on the outcomes; however, such a project is beyond our organizational scope and capacity.
TWEJ: Would reconnecting it to the ocean be a viable option?
SPE: Stanley Park Ecology has not conducted any studies on this possibility, as it is beyond our organizational scope and capacity.
TWEJ: Should we expect similar algae blooms in the future?
SPE: So long as conditions remain the same, and nutrients continue to build up, Lost Lagoon will continue to experience algae blooms, the extent of which would depend on timing and the environmental factors discussed above.
TWEJ: Anything else worth noting about the algae blooms that I didn't ask?
SPE: Stanley Park Ecology has been conducting bi-weekly field water quality surveys every summer since 2021. Over time, this long-term monitoring effort will hopefully help us better understand the complexities of these highly impacted urban freshwater bodies.
We are looking into incorporating algae formation into our annual habitat monitoring plans.
LEARN MORE ABOUT THE LAGOON’S RESIDENTS
Stanley Park Ecology Workshops Share Their Stories
a KINGFISHER in flight over lost lagoon. (Bird photos by frank Lin)
Frank Lin, from the SPE Nature House, shared with me that there are four beavers in Lost Lagoon and two or three in Beaver Lake. Beavers are crepuscular, meaning they are most active during the early morning hours and dusk. They can be spotted swimming with small branches on the west side of the Lagoon and around their lodge near the concrete bridge. Wood ducks like to live in beaver habitat. They like the stagnant water the beaver dams create, and as they are perching ducks they enjoy the fallen trees and branches that beaver activity produces.
The river otters have not been so prevalent in Lost Lagoon since the deaths of the carp a few years ago.
On August 21, Stanley Park Ecology posted a video of a lone river otter swimming in the Lagoon. Look for otters close to Coal Harbour and on the seawall near the Lions Gate Bridge.
Stanley Park Ecology presents a variety of workshops several times a month. The workshops are fun and informative. Please check their website for upcoming events. On Wednesday, August 20, I participated in the “Herons of Lost Lagoon” workshop.
At this time of year, the herons have left the famous hatchery near the tennis courts and spread around Stanley Park and the Lower Mainland. The Stanley Park heron colony is the largest urban heronry in B.C. There are two larger colonies in Tsawwassen and Chilliwack, but they are not classed as urban. A new, developing heronry can be found near the Vancouver Aquatic Centre near Sunset Beach. Let’s hope the upcoming construction does not affect it.
Herons can live between 10 and 18 years, but only about 25 per cent of herons survive their first year. Great Blue Herons are classified as a species at risk in areas other than Stanley Park. Although the Stanley Park herons are uniquely accustomed to humans, it has been noted that Great Blue Herons in areas experiencing human activity can lead to nest abandonment.
a MERLIN in stanley park in search of its next meal.
The greatest predators of herons are eagles, owls, and raccoons.
The SPE workshops often lead to much more information than the website promises. On our Great Blue Heron walk around Lost Lagoon, Frank Lin pointed out a Northern Shoveler, a Kingfisher and a Merlin. I would not have noticed had I been walking alone.
The Merlins are especially fascinating to me. The app “All About Birds” describes them as small, fierce falcons that use surprise attacks to bring down small songbirds and shorebirds. They are about the size of a pigeon (they used to be called pigeon hawks) and in Medieval times were called lady hawks. If a flock of shorebirds suddenly takes flight, look for a Merlin.
THE MERLIN BIRD APP
I have written before about the wonder of using the Merlin Bird App. Created by the Cornell Lab of Ornithology, it is free!
Opening the app, look for the green circle, titled “Sound”, with a drawing of a microphone. Click on the green circle, and the app will identify all the birds singing around you. It is pure magic. Use it on the trails in Stanley Park, where the huge number of identified bird calls is more than one can imagine.
an OSPREY cruising over stanley park.
On two different mornings, on the same trail, the app identified a nearby Osprey. These magnificent large raptors are found on every continent except Antarctica. Look for them fishing feet-first from great heights. Finding them in our city is a testament to the importance of Stanley Park.
Frank also informed us that only one eagle nest was successful in Stanley Park this year.
English Bay is an area of significance for water birds. It is formally recognized as part of the English Bay-Burrard Inlet Important Bird and Biodiversity Area. For instance, in the winter, the sheltered waters of English Bay provide a safe area for thousands of waterfowl migrating from the cold winters in Canada’s North. These shorelines are important for breeding birds.
A bee on your window ledge needs a hand.
HELP PROTECT THE BEES
Don’t forget to rescue bees that you spot inside your apartment windows and on sidewalks.
Use a small glass to help them move out of your apartment, or use a leaf to pick the bees from the sidewalks, and place them on a nearby plant.
