Friday, August 24, 2018

Rogers Refuge and the Importance of Stewardship


Looking out on this wetland, you would understandably think you aren't in Princeton anymore. But this broad and beautiful marsh, the centerpiece of Rogers Refuge, is just a short drive upstream from Alexander St, off West Drive.

The Friends of Rogers Refuge (FOHR), which has been quietly caring for this renowned bird sanctuary, turns 50 this year. Comprised mostly of devoted birders, the Friends group grew out of actions by the Princeton Environmental Commission in 1968 to halt filling of the marsh. A prominent ornithologist named Charles H. Rogers was among those who led the campaign.


A conservation easement renewed every ten years has helped to protect the wetland since, but no habitat is protected by a paper agreement alone. Though auspiciously located in the floodplain, between the Stonybrook and the Institute Woods, the habitat benefits from a collaborative effort of the landowner (NJ American Water) the town of Princeton, and the Friends group. For instance, though the wetland receives runoff and groundwater seepage from the Institute Woods, and occasional floodwater from the Stonybrook, the habitat benefits from a steady input of water pumped from the river during the summer months. The water company pays for the electricity to run the pump, the town helps with repairs, and the Friends keep an eye out to respond quickly to any breakdowns. The Washington Crossing Audubon Society not only leads walks there during bird migration in May, but has also funded much of the Friends' efforts to restore habitat and build observation towers. They also funded an ecological assessment and stewardship plan I did for the Friends in 2006.


Talk to members of the group and they will tell you excitedly about the kinds of birds they see at the Refuge. Since birds require habitat, much of the group's active stewardship centers around controlling invasive species. Though the native cattails can be a little aggressive, its the nonnative Phragmitis that poses the greatest threat to a balance of plant life in the marsh. In this photo, the cattails show as dark green, with wild rice appearing as light green in the distance. In the foreground and to the left is the browned remains of Phragmitis reed, killed with low-toxicity, wetland-safe herbicide. When a similar treatment was applied 12 years ago, the void left by the Phragmitis was quickly filled with a great diversity of native wetland species.


The same can be expected this time. Hopefully, another such large scale treatment will not be necessary if there's sufficient followup to prevent the few remnants of Phragmitis from rebounding. It's human nature to shift attention elsewhere when a threat has been greatly diminished, but when dealing with invasive species, that's when vigilance is most needed.

Another example is chocolate vine, which I discovered growing next to the small parking area at Rogers Refuge. This is the only location in Princeton where I've encountered chocolate vine, yet its behavior suggests it could quickly become a problem if left to grow.

Its rapid expansion at Rogers Refuge, up trees and over bushes, should make any homeowner think twice about growing this nonnative species, lest the birds carry its seeds to a nearby nature preserve.

Porcelainberry is another invasive plant that has shown up at the Refuge in recent years, and has quickly begun dominating woodland edges. A look behind the Clark House at the nearby Princeton Battlefield shows how dominating this vine can become if left unmanaged.

Further evidence that a wildlife refuge doesn't take care of itself came a few years ago, when I discovered a third nonnative vine with highly invasive behavior, appropriately named Mile-a-Minute, growing along the driveway that leads to Rogers Refuge. A thorny annual with a distinctive triangular leaf, it too has proven extremely aggressive elsewhere in NJ. We've been fortunate to catch it early in Princeton, and respond quickly before it produces seed and spreads around town.

Heavy browsing from deer has been a problem in past years, but the town's investment in deer culling, since 2000, has not only dramatically reduced car accidents in town but also greatly benefitted habitat at the Refuge and elsewhere. The birders report that the return of a healthy understory of spicebush, previously almost eliminated by the overcrowded deer, has brought back ovenbirds that depend on the shrubs for nesting habitat.

Another challenge that the Friends of Rogers Refuge has faced, as have other Friends groups in Princeton, is vandalism. Again, it's the generosity of volunteers in the community who respond by repairing what is broken, as in this email sent to the Friends:
"I am pleased to report that the informational signs at the Refuge, ripped from their frames on the main platform by vandals a year ago, have been restored. Many thanks to the hard work and generosity of Charles Magee, who remounted them with a more secure system. Visitors can again find pictures and descriptions of some of our most attractive birds close at hand. Thank you, Charles!"
Erich Fromm best captured the ongoing struggle between vandalism and repair in his book, Escape from Freedom:
“The more the drive toward life is thwarted, the stronger is the drive toward destruction; the more life is realized, the less is the strength of destructiveness. Destructiveness is the outcome of unlived life.”

Leading the group in recent years has been Fred Spar (left), with particularly active support from his wife Winnie and Lee Varian (right). Fred reported to me that there was a particularly good spring bird migration this year, perhaps the best they've ever had, due in part to winds that shifted migration routes eastward. From the observation tower can be seen a purple martin house erected in the middle of the marsh by the Friends. It was alive with the comings and goings of the purple martins earlier this summer.

If you stop by this hidden gem, wish a happy 50th to the group that through quiet persistence and dedication has kept Rogers Refuge well cared for.

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