Prove your humanity

This story is part of our series, Wild Pennsylvania. Check out all of our stories here

Many of Pennsylvania’s natural areas are filled with invasive species, which are non-native plants, animals and other organisms that wouldn’t be there except for human activities. Invasives grow quickly and aggressively and outcompete native species for food, habitat and other resources. There are more than 180 non-native species in the Great Lakes region.

A short film by the Western Pennsylvania Conservancy and Great Lakes Media & Film, “Seeing The Unseen: Aquatic Invaders & What’s at Stake,” features some of the aquatic invasive species threatening the Lake Erie watershed and nearby region and efforts to reduce the threat to these ecosystems.

“Just because you’re paddling along the shoreline and see lots of vegetation does not mean that it’s all good, said Tyson Johnson, the conservancy’s land stewardship manager, in the film. “There can be a small pocket of invasives, and then the next year you come out, it’s a little bit bigger and a little bit bigger, and eventually it can take over and wipe out an entire area.”

To learn how these ecosystems are being impacted and what people can do to help, The Allegheny Front’s Julie Grant spoke with Mary Walsh, the invertebrate zoology manager for the Pennsylvania Natural Heritage Program at the conservancy and executive producer of the new film

LISTEN to their conversation

Julie Grant: In the film, you focus on three waterways in northwestern Pennsylvania: the tiny Lake Pleasant, which has been overrun by invasive cattails; the popular fishing destination, French Creek; and the Presque Isle area of Lake Erie, which is considered a haven for many threatened and endangered plant and fish species. Why did you feature Presque Isle?

Mary Walsh: Presque Isle State Park is one of the most visited parks in Pennsylvania, and it’s beloved by many for its beaches and its fishing. But it’s also a very challenging place to manage invasive species.

There are four million people a year that come to the park, and visitors can unintentionally bring invasive species there. It’s such a unique setting. It has plants and animals that don’t occur anywhere else in Pennsylvania. And because of this, it’s an area that has really important ecological resources but also has a lot of invasive species that arrive there. 

Julie Grant: According to the film, $25 million is spent annually in the Great Lakes region to manage just one invasive species, a parasitic fish called the sea lamprey, and Presque Isle spends $84,000 a year to manage a stringy-looking plant called starry stonewort

Clip from the film (Dr. Jim Grazio, PhD, PA Dept. of Environmental Protection): I’m a fish guy. That’s my expertise. Plants usually don’t excite me. Starry stonewort excites me. And not in a good way. This is one that I’m most concerned about.”

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Wide shot of lagoons winding through land by Lake Erie at Presque Isle State Park.

Lagoons at Presque Isle State Park, along Lake Erie. Photo courtesy of Great Lakes Media & Film

Julie Grant: Starry stonewort likely got to Lake Erie in the ballast water of ships, and it’s starting to take off in some of Presque Isle lagoons. What is the concern?

Mary Walsh: The concern is the cascading effect of – if you’re starry stonewort and you’re growing over all of the habitat there, you are eliminating our native aquatic plants, and you’re growing into the habitat that supports that wonderful fishery in Presque Isle Bay. 

Julie Grant: The film mentions the $7 billion fishery that draws five million anglers a year and supports 75,000 jobs in the Great Lakes region. 

Another area featured in the film is French Creek, a 117-mile-long tributary of the Allegheny River. What’s unique about the biodiversity of French Creek? 

Mary Walsh: It contains more species of fish and freshwater mussels than any other similarly sized stream in the northeast United States. It’s also at the forefront of a new invasion from round goby. 

Green underwater scene showing round goby

Round goby. Courtesy of Great Lakes Media & Film

Julie Grant: In the film, we learn about round goby, a small but aggressive bottom-dwelling fish. It’s already prevalent in Lake Erie and is now finding its way to French Creek. So, what’s the status of this invasive in the French Creek watershed, and why is it so concerning? 

Mary Walsh: There’s a lot of diversity of native fish in the French Creek watershed, 15 darters, which are also benthic bottom-dwelling fish. And so we are concerned about round gobies competing for space or excluding native darters from their natural habitat.

In addition, there is evidence that they are eating native freshwater mussels in French Creek. It’s such a wonderful stronghold for native freshwater mussels. We have seven endangered freshwater mussels in that region, and there’s just a concern that there could be long-term impacts to the populations. 

Clip from the film (Casey Bradshaw-Wilson, Ph.D, Watershed Conservation Research Center, Allegheny College):One of the things that people forget is how intricately everything is connected when you’re working and living and recreating in an ecosystem. You can only pull so many pieces out of the ecosystem before things start to fall apart. And so, keeping our native species here and having them play the roles that they’re meant to play in the ecosystem is really critical to keeping the entire food web and ecosystem in check.” 

Mary Walsh: It [round goby] was spotted in Lake Leboeuf in 2013, which is a tributary to French Creek. And we’ve been monitoring the situation ever since. 

Clip from the film (Casey Bradshaw-Wilson, Ph.D, Watershed Conservation Research Center, Allegheny College):My biggest fear is that they’ll be introduced to the other lakes in the watershed, and then we would have all of these lakes pumping round gobies out. And that’s where we’ll really start seeing huge impacts on the watershed as a whole.”

Julie Grant: A couple of years ago, I met with experts from the Western Pennsylvania Conservancy to report on efforts to protect Lake Pleasant from invasives, and that’s another focus in the film. Why is there so much attention on such a small lake? 

Mary Walsh: Lake Pleasant is another very unique and precious habitat in northwest Pennsylvania. It’s one of the best examples of a naturally formed calcareous inland lake in the region. It was created by glaciers. It’s one of our best examples because it’s relatively undeveloped, and so it’s unique, and [its] wetland communities are relatively intact. But it is also threatened by invasive species. 

A closeup of a person holding an invasive cattail.

An invasive cattail at Lake Pleasant. Photo courtesy of Great Lakes Media & Film

Julie Grant: The film focuses on efforts to eradicate an invasive population of cattails at Lake Pleasant using a painstaking process of applying herbicides by hand. How can we balance the desire for people to visit these places with keeping invasive species at bay? 

Mary Walsh: We want people to get out and enjoy these beautiful places and get the understanding of how important they are, and there’s no other way to do that than to experience them.

If you’re out in a kayak on Lake Pleasant, experiencing a beautiful morning, the sunshine and the wind on your face, and taking in the beautiful scenery, that would be really meaningful to you. And so we want people to be able to get out there in their boat and then enjoy it and recreate there. That’s so important.

But we also need people to know that they have to be stewards of these places that they so enjoy, and that they need to be careful not to bring in an invasive species, and not to take them to new places. We really want to keep Lake Pleasant as pristine and beautiful as it is. 

Grant: What else can people do to stop the spread of invasives? 

Walsh: We want you to…keep an eye out for invasive species. If you go to a spot, and you see this large monoculture of something growing, or if you see something unusual, something that you never saw before, make a note, take a picture, record where you are. You can help by reporting it to Pennsylvania iMap Invasives.

We want you to be a good recreationist, be a responsible steward, to make sure you clean your gear when you go from one place to another, make sure you’re not bringing mud on your boots that could contain seeds or other things that could be spread to that next beautiful hiking spot you go to.

Mary Walsh is the invertebrate zoology manager for the Pennsylvania Natural Heritage Program at the Western Pennsylvania Conservancy and executive producer of the new film, “Seeing The Unseen: Aquatic Invaders & What’s at Stake.”