Study shows deer grazing costs Fox Chapel native plant life
Nancy Fales remembers when trillium flourished in Fox Chapel's forests.
The plants made it difficult for her and her friends to hike in the woods almost seven decades ago.
“People used to come from all around to see the trillium, and then all of a sudden, there were almost no trillium,” said Fales, 74, of Fox Chapel, citing overabundant deer as the reason for the change.
A study led by Susan Kalisz, a professor at the University of Pittsburgh, supports Fales' view that deer have overgrazed native plants they find appetizing, which results in nonnative plants that deer won't eat taking their place.
The study examined the relationship between deer, native edible plants such as trillium and a nonnative plant called garlic mustard in Fox Chapel's forests since 2003. Volunteers plan to pull up garlic mustard plants on four days this spring, which follows up on April 2013 events in which 125 bags of plants were removed.
In the Pitt study, researchers established seven pairs of 196-square-meter plots, half of which excluded deer with fencing. One pair of plots was knocked out by the remnants of Hurricane Ivan in 2004, which left six pairs in the study.
Results from 2003 to 2008 showed that the six fenced-in plots reversed the impact of deer.
While garlic mustard decreased by 12 percent annually, 26 percent of native plants in the those protected plots reproduced. The study projected that garlic mustard eventually would go extinct without the presence of deer.
In plots that weren't protected against deer, garlic mustard increased by 30 percent annually, and only 5 percent of native palatable, or pleasant tasting, plants reproduced.
Fox Chapel has used archers and a two-man sharpshooting team on its police force to try to control the borough's deer population since 1993.
Police Chief Dan Laux said the Pennsylvania Game Commission's standard for deer in a community is equivalent to 20 to 30 deer per square mile of forest. With 3.5 square miles of forest in Fox Chapel, Laux said, the target is 65 to 90 deer, though the estimated deer population probably is somewhere between 200 and 300.
“Our goal will never be to eradicate the deer population in the borough,” Laux said.
Fox Chapel Sgt. Mike Stevens said it's difficult to gauge the borough's deer population, but the department views a drop in vehicle collisions with deer as an indicator of the program's effectiveness. There were 81 vehicle collisions with deer in Fox Chapel in 1993, and there have not been more than 22 in a year since 2005.
While archers may keep the deer meat, Stevens said, the department donates deer it shoots to a processor, and the meat is sent to local food banks.
Marilyn Bruschi, co-chairwoman of the Garden Club of Allegheny County's Native Plant Initiative, said she encourages gardeners to plant native species.
While the study is in its final year, Kalisz and other researchers are drawing up a proposal for more funding from the National Science Foundation to continue their research.
Fox Chapel Park Commission chairman James Pashek said garlic mustard pulling will take place April 26 and 27, as well as on May 3 and 4 in Fox Chapel. Sessions run from 9 a.m. to noon and 1 to 4 p.m. each day. For details, call the Fox Chapel borough office at 412-963-1100.
Shawn Annarelli is a freelance writer for Trib Total Media.