Rare plants popping up all over Presque Isle after dry spell

As Jim Bissell walked through the sandy plains of Presque Isle State Park in the past few years, he felt as if he had hit the wild plant bonanza.

Emerging from the sand were hundreds of plants that were usually rare to find. One species had never been spotted before at the park; another hadn’t been reported in decades.

The long-lobed arrowhead first showed up in western Pennsylvania on a Presque Isle inlet last year. By August, more than 1,000 of the plants covered a quarter acre of the inlet.

In 2001 alone, Bissell and his colleagues found 52 new locations with rare plants at Presque Isle.

“Last year it was the mother lode,” said Bissell, a botanist with the Cleveland Museum of Natural History, who has been studying the park’s plants for the Wild Resource Conservation Fund since the 1980s.

The record sightings for rare plants were directly related to Lake Erie’s recent near-record low water levels, which dramatically affect the park’s palustrine sand plain community — one of the rarest types of plant communities in Pennsylvania.
Presque Isle is a 7-mile ridge of sand left behind as glaciers retreated 13,000 years ago. Lake Erie gradually rose around the ridge as the glaciers melted, creating a peninsula.

The lake levels continue to rise and fall today. As this happens, the texture of the sand plains behind the ridge changes too. The shallow groundwater rises and falls with the lake level, changing the moisture of the sand. Ponds in the sand plain fill with water as the lake rises, then nearly dry up in years when the lake level is low.

While the palustrine sand plain community is always present, the types of plants change with the water level. When Lake Erie is low, a number of plant species that survive through their ability to “seed bank” begin to pop up in the ponds.

These plants compete poorly with other, more aggressive species. But when the ponds begin to dry, seeds that have been dormant for decades burst forth. For a year or two, they can rule the site until other plants move in, or the pond water rises. During that time, they will germinate a new crop of seeds which will be deposited in the moist sand and will survive while those of other plants die.

“If you could somehow stabilize lake Erie, you would destroy that system,” Bissell said. “It is driven by the rise and fall of the lake.

Until it showed up at Presque Isle two years ago, the dwarf spikerush had only been seen in Pennsylvania along the Delaware River near Philadelphia.

Last year, Bissell and colleagues discovered the first western Pennsylvania occurrence of the long-lobed arrowhead (Sagittaria calycina), an endangered plant in the state, which was discovered in a small, dry inlet on Presque Isle’s west side.
In recent years, the inlet had been covered by Lake Erie’s high water levels. But in 2001, the bottom of the inlet was gradually exposed as the lake dropped to its lowest level in decades.

As the water receded, the “seed-banked” plants sprang to life; by August, more than 1,000 long-lobed arrowhead plants covered a quarter-acre of the inlet’s moist bottom.

Similarly, Smith’s bulrush (Schoenoplectus smithii), another endangered plant, abounded in the same inlet. Unlike long-lobed arrowhead, Smith’s bulrush had been seen at the inlet before, but no more than 17 plants had ever been counted.

Last year, botanists counted more than 1,000. “You could hardly walk without stepping on them,” Bissell said. And — as water levels dropped at other ponds — Smith’s bulrush popped up at 10 other widely scattered sites along the peninsula. “I did not know it was throughout the park,” Bissell said. “I thought it was only in that one part of the park.”

Other rare plants were found as well. Altogether, Bissell reported that rare plants were discovered at 52 previously unreported sites at Presque Isle, a number he called “astounding.”

Presque Isle has been studied intensively for more than a century. Botanist Otto Jennings published the first analysis of its vegetation in 1909.

Since then, there have been only a few periods where water levels have dipped as low as in recent years, which left great potential for new plant discoveries — but only a short window of opportunity to make them.

“These are ephemeral community species,” Bissell said. “They don’t compete well, so they don’t last. Once those flats are exposed, if the lake continues to drop, in a few years it is taken over by more aggressive perennials.”

Last year was the third year that Bissell and his colleagues had taken advantage of low water levels to find new plants.
Two years earlier, Bissell found dwarf spikerush (Eleocharis parvula) at a site which previously had been underwater for 15 years. The only other place that the state-endangered plant had previously been seen was along the Delaware River near Philadelphia.

Frank Felbaum, director of the Department of Conservation and Natural Resources’ Office of Wild Resource Conservation, suggested people should take a lesson from the seed-banked Presque Isle plants.

With nearly a third of the state’s native plants considered to be in trouble, he said their long-term survival may hinge on people developing seed bank technologies for other rare species. Then, the plants could be returned in the future if the threats to their habitats, such as invasive species, pollution or other problems, are reduced.

“Plants indigenous to Pennsylvania should be seed-banked for development at a later date,” Felbaum said. “We may not have the technology today, but 10 years, 20 years, or 50 years from now we may have the technology to create like habitat.”

In the meantime, Mother Nature’s own seed bank will stay in place for rare species at Presque Isle. Water levels are back on the rise this year, but Bissell plans to be ready the next time Lake Erie takes a dip. “I love these dry years,” he said. It’s great for us.”