Portland Parks & Recreation has released the most comprehensive report to date on the wildlife inhabiting the city's 5,400-acre Forest Park natural area.
I was just marveling at a picture of the park, right, that offers no indication that it's an urban forest. The Parks report explains that there is plenty of evidence of urban impacts on the park, but there are also a tremendous number of native wildlife species that have been documented through surveys, studies, remote cameras, public reports and bird counts and this year's "Bioblitz" (see video above).
The report notes which species are abundant, which are in decline or threatened, and which ones are still unknown. It outlines the threats to wildlife in the park, including climate change, invasive plants and insects, habitat impacts outside the park, illegal park activities, domestic cats on the park's perimeter, air pollution, water quality degradation, rat poisons making their way up the food chain, animal control "persecution" of pocket gophers and coyotes and fire.
"This is the very first time we've put all the information together looking both at the research and anecdotal data," said Emily Roth, natural resource planner for Portland Parks and Recreation. "What really popped out to me is that most of the species in Forest Park are native. We really have very few non-native species, and they're really only found on the fringe. They haven't really infiltrated into the park."
You can probably guess many of the wildlife species listed: bats, squirrels, mice, beaver, raccoons, salamanders, owls, warblers … but some rare species are a little more surprising for an urban forest, including peregrine falcons, northern spotted owls, silver-eared bats and northern red-legged frogs. According to the report, there are no turtles in the park. No wolves, either.
"It's really good interior forest habitat," said Roth. "That's why we're finding the sensitive species there. At least from a wildlife perspective, the park is in good shape."
The report also outlines the gaps in knowledge about park wildlife, for example: why are red and gray foxes declining? How do wildlife respond to people and their dogs? Could woodrats and voles be reintroduced to the park?
It takes a look at the history of the park, from pre-1900 when the park was connected to the Willamette River, Tualatin Valley and coastal forests through wetland, riparian forests and old-growth forest, savannahs and grasslands. Fire, logging and development wiped out a good deal of the forest canopy by 1960, which shifted many species away from the park. But by 1990, some of the canopy had returned and species such as the pileated woodpecker came back with it.
The park is now a "narrow extension" of the Coast Range, according to report. So, even though it's surrounded by urban and industrial development, power lines and roads, it still provides habitat to similar wildlife species.
"This report highlights how important it is to have the wildlife connection to the Coast Range and Willamette River," said Roth. "We have all this native wildlife because the park is so big and has so much interior habitat."
Roth said the next step for Portland Parks is to review the report and outline some management responses to its findings.