Invasive species, off-leash dogs, squatters, mountain bikers and global warming are all contributing to the decline of the ecological health of Stanley Park, says the author of a new report released to the public this week.
Sitting in the program room on the top floor of the Stanley Park Ecology Society, conservation programs manager Robyn Worcester flips through a large binder containing the 230-page report she spent three years completing. The groundbreaking State of the Park Report for the Ecological Integrity of Stanley Park, the first of its kind in Stanley Park's 120-year history, is an inventory of the ecological health of the iconic green space. Worcester hopes her findings will one day serve as the foundation for a future Stanley Park master plan created by the park board. Worcester says the format of the report is based on a similar model used by Parks Canada.
"In order to gauge the ecological health of the park, you need to know what you've got, so I suggested an inventory," says Worcester.
She says following the devastating windstorm that ripped through Stanley Park in December 2006, the society participated in the massive restoration alongside parks staff and biology and forest experts. "There were all of these professional experts and academics involved after the storm and we were able to work side-by-side with them," she says. "It was kind of serendipitous so many trees blew over because it gave us the opportunity to really study some environmentally sensitive areas. But even before the windstorm, I was identifying important resources and compiling data."
The ecological health of the park was assessed and evaluated by rating specific environmental indicators that provide a broad representation of key factors influencing its ecosystems. In areas with little data, professional evaluations were used to assess current conditions and future trends. Worcester notes the ecological integrity of the park will never be fully known due to its size, location and the past and present influences that surround it, such as human use, development and logging.
In the report, Worcester uses coloured indicators to demonstrate the health of specific categories, including natural disturbances, management operations, environmental, social issues, climate and atmosphere, terrestrial ecosystems, native biodiversity, native wildlife and aquatic ecosystems. She's also included her predictions regarding whether the ecological health of those categories are declining, improving or remaining as is.
It's the aquatic ecosystems that have Worcester and other members of the society most concerned. Worcester rates the health of aquatic ecosystems in the park as poor and declining, including those of Lost Lagoon. The report notes overall aquatic systems in the park are declining in quality and size.
According to the report, Lost Lagoon was originally an inter-tidal mud flat before it was separated from Coal Harbour by development of the Stanley Park Causeway. The unnatural formation of the lagoon and periodic inflows of salt water, make it largely unproductive. Although the lagoon supports large numbers of over-wintering birds, it has little to no submerged vegetation and contains mostly invasive fish and herptiles, such as American bullfrogs, an invasive species that's obliterated the native frogs that once lived there.
Invasive species are identified as those introduced to the park by humans, are outside their natural geographic range and put stress on native biota and ecosystems. These species, such as English ivy, grow and spread rapidly and thrive in new environments. Worcester points out invasive species represent one of the greatest threats to biodiversity in the world today. Many of the invasive species in Stanley Park were introduced deliberately and include unwanted pets such as red-eared slider turtles--the same ones sold in pet stores. It's thought the red-eared turtle is responsible for the disappearance of the native western painted turtle, which once thrived in Beaver Lake.
COPE commissioner Loretta Woodcock, the park board's liaison to the ecology society, is particularly concerned about Beaver Lake. The lake is one of the last natural wetlands in Vancouver with a watershed of 1.9 kilometres of tributaries and 112 hectares of primarily coniferous forest. According to the report, since the watershed and lake were permanently altered with the completion of the Stanley Park Causeway in the 1930s, Beaver Lake has been shrinking due to a combination of the introduction of invasive water lilies, accelerated sedimentation and an increase of aquatic plant growth that depletes oxygen levels in the water. Woodcock says Beaver Lake has shrunk from 6.7 hectares in 1938 to 3.9 in 1997.
"However, what caught my attention was that the western painted turtle was once present in Beaver Lake, but there has not been any reported sighting for years," says Woodcock.
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"What this potentially means is that we have lost an indigenous species right under our noses," added Woodcock. "No explanation is currently available for this loss. As a municipality, I think that we need to find out what is the cause of this loss."
As a result of this finding in the report, last month Woodcock and members of the park board's planning and environment committee asked staff to report back this September on the ecological health of Beaver Lake and what factors could have caused the disappearance of the turtle. The board was to vote on that last night.
By coincidence, last month the municipality of Saanich on Vancouver Island became so concerned about losing its western painted turtles, it installed warning signs along Beaver Lake Road advising motorists to slow down and watch for hatchlings crossing in their efforts to find their way from their nests to the nearest pond.
"The city of Saanich recognizes that the western painted turtle, designated endangered in 2006, is the only native turtle left on Vancouver Island and it's believed only a few hundred remain," she says.
She says Saanich's environmental education officer, Darren Copley, will measure vehicle speeds before and after the road signs are installed and adds the city is considering building a turtle tunnel under the road.
Woodcock suggests Vancouver, with its missing western painted turtles at Beaver Lake become a "sister turtle city" to Saanich.
"Perhaps some of the turtles from Saanich could be rescued from their precarious journey across Beaver Lake Road and transplanted to Beaver Lake in Vancouver's Stanley Park," she says. "We could become twin turtle cities."
Woodcock says during the Stanley Park restoration, a fundamental principle was to ensure all of the work done would be completed in a way that protected the park's natural and cultural environments. From that came the Stanley Park Forest Management plan, a 49-page report detailing goals and objectives to guide forest-related projects and programs through the next 10 to 20 years.
"The Stanley Park Ecology Society report is a sterling example of one of the goals of the Stanley Park management plan, which suggests compiling ongoing data for ecosystem monitoring and public education," says Woodcock.
Last June, the park board approved the final report of the Stanley Park restoration plan. That report includes 10 goals and objectives, including tree inspection and safety management, fire management, invasive species management and forest health.
"The ones in the management report that speak to the situation around Beaver Lake are invasive species management and managing wildlife and habitat," says Woodcock.
Woodcock says the hard work completed by Worcester and the society, including laboriously sifting through scientific reports and research data, resulted in a useful resource document the board can use in managing forest, animal, plant and insect life in the park. "And for assessing ecological changes in the decades to come," says Woodcock.
Worcester is encouraged the park board is taking the shrinking of Beaver Lake seriously. She says the disappearance of a relatively small lake can be natural, but the speed at which this one is shrinking is alarming. Worcester estimates if no changes are made, Beaver Lake could completely disappear by 2020.
The water lilies, introduced to the area in the 1930s, are a large part of the problem and are choking much of the original habitat and filling in the lake.
Worcester says it's an important lesson in the danger of introducing invasive species where they don't belong.
Worcester also reported park maintenance, such as keeping trails clear and lawn mowing, is more beneficial to humans than it is to the ecology of the area.
She adds park maintenance often has a negative impact on wildlife habitat. With that in mind, she'd like the park board to complete maintenance at times that are the least disruptive to wildlife, particularly to nesting birds.
Worcester says the report could never have been completed without the thousands of hours donated by volunteers, including West End residents, regular park visitors, university students and many retired professionals, including biologists, naturalists and historians.
It was a group of invertebrate researchers from the University of B.C. forest science program, taking part in the park board's restoration project between 2007 and 2008, that documented 15 ground beetle species, 190 moth species and 67 rove beetle species, including two new to science, recently named Oxypoda stanleyi and Sonoma squamishorum.
Those beetles are one of the concerns Worcester has when it comes to mountain bikers who like to ride off-trail in the park. She says there are entire ecosystems thriving under the natural debris on the forest floor.
"These mountain bikers just think it's dirt, so what's the big deal," says Worcester. "But it's a problem."
Squatters also often camp off-trail, which besides creating a fire risk, causes damage to the delicate ecosystems they trample on their way into the park.
Off-leash dogs can also cause ground damage, in addition to chasing birds and wildlife.
Many of the volunteers captured the once in a lifetime photographs included in the report, such as one of a coyote that recently moved into the park, standing on a beaver lodge. A beaver recently moved back to Beaver Lake, the first sighting since 1988.
It was also many of these volunteers who supplied Worcester with dozens of reports, studies, books and individual observations, which she pored over in her search for information. Worcester suspects there's more information out there in private homes and hopes this report will encourage people to contact her about their collections.
"This is the first time all of this information has been gathered in one place," she says. "So far I've gone through all of the literature that's known."
Worcester's recommendations include maintaining existing monitoring programs and creating new ones to track changes in the park's ecological health and she suggests undertaking restoration and enhancements to benefit the ecology and biodiversity of the park's ecosystems, with priority given to aquatic species and habitats, environmentally sensitive areas, invasive species management, species at risk and human-causes stressors. Worcester also wants the society to continue offering environmental education in the park and suggests the report be updated on a regular basis.
Society executive director Patricia Thomsen wants the report to eventually be used as baseline data by the park board for future planning. She adds five years from now it will be interesting to see what ecological changes have taken place.
"We haven't had that in the past," she says. "So we've had no way to tell if the park is healthy or declining. And if we see the ecological health declining, we'll have the opportunity to fix it."
Brian Quinn, acting manager of horticultural operations for Stanley and Queen Elizabeth districts, says it's important to note the report deals strictly with the ecological health of the park and doesn't include any cultural references.
"But having said that," he says, "it's definitely an excellent tool for moving forward."
He adds the report was completed concurrently with the park board's recent forest management plan, both of which he considers valuable documents. Quinn says at this time there is no official management plan for Stanley Park and notes the last one completed was so long ago, he's unsure of the date.
"At this point we are not acting from a management plan," he says. "And this report could help us with our management of the park. The rating system it gives is also very useful and will help us identify areas where work is needed."
sthomas@vancourier.com
(See related story on page 14)
