Cutting the Grass: Rachel Benbrook Takes on Invasive Spartina

Guemes Island resident Rachel Benbrook heads the Spartina Survey Program for People for Puget Sound. Photo by Liam Moriarty

Invasive species of plants are usually introduced to an area to solve one problem, but often end up causing other, bigger problems. In the Salish Sea, one of these headache is spartina grass.

This week in our series “Reflections on the Water,” KPLU environment reporter Liam Moriarty meets up with Rachel Benbrook. She heads a program that recruits volunteer sea kayakers to help eradicate spartina. Liam and Rachel paddle through the Swinomish Channel in Skagit County in search of the noxious weed

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Liam Moriarty: So we got some over there?

Rachel Benbrook: Yes; I see some spartina in this marsh right here.

Liam: Okay; let’s get in on that … Hi,Rachel!

Rachel: Hey, Liam!

Liam: Where are we at right now?

Rachel: What we are looking at right now is a really beautiful native, Salish Sea salt marsh. There’s lots of the pickle weed grass, the arrow grass and other native species in here. But unfortunately there’s also some invasive spartina.

Rachel Benbrook displays a sample of invasive spartina grass. Photo by Liam Moriarty

Rachel Benbrook logs the GPS coordinates of a patch of spartina grass in Swinomish Channel near LaConner. Photo by Liam Moriarty

Liam: Tell me about spartina grass.

Rachel: Spartina is a family of invasive grasses that has found its way here into Puget Sound. The grass was actually deliberately planted in the Puget Sound in the Stanwood area in the 1960s to help stabilize the dikes there. It happens to hold a lot of sediment in its roots which means it’s really good at doing that. But it’s also invasive.

Liam: What does it do?

Rachel: Once spartina gets established, it spreads really, really quickly. I’ve seen plants double in size in one growing season.

Liam: It just kind of takes over …

Rachel: It takes over and unfortunately, the habitat that it prefers are really high quality estuary and marsh and mudflat habitats.

Liam: So when spartina takes over one of those habitats, is it basically just not good for much of anything else?

Rachel: Eventually it starts to become nothing but a spartina meadow and it is only good for more spartina seeds that continue to spread through the really active currents of Puget Sound. In fact, from that original infestation site in the Stanwood area, we found spartina as far south as Vashon Island and all the way out west on Neah Bay. It’s also spreading up into British Columbia.

Liam: Point the spartina out to me; what does it look like?

Rachel: Alright; it’s right here. I’m just going to kind of stick my paddle by it so you can see it.

Liam: Okay. It looks like something you might see in your lawn.

Rachel: Right; that’s one of the things that drives spartina surveyors crazy because you see it everywhere. It’s a plant with attitude, kind of; once you learn to recognize it, those sharp leaves kind of stick up out of the marsh.

Liam: You’re in charge of a program – it’s kind of a citizen science program having to do with spartina grass; can you talk about that?

A kayakers-eye view of a salt marsh near the south end of Swinomish Channel in Skagit County. Photo by Liam Moriarty

Rachel: I’m with People for Puget Sound, and have the incredibly cool job as a sea kayaking biologist, of working with volunteer kayakers to get them out on the water, and train them how to do surveys for the spartina grass.
We work with regular citizens of Puget Sound to get them out there doing science and collecting data for the researchers who are then applying that and getting out here and dealing with the spartina that’s out here in the Sound.

Liam: I’m a paddler myself, and it occurs to me that there are a number of ways in which, by the nature of the craft and the way paddlers get around, that they could be actually pretty useful gathering field data for scientists.

Rachel: For one thing, a kayak only draws about three inches of water, so we can be in these super shallow areas such as the mudflats and deltas where we see a lot of spartina. We’re able to get into areas in a really, really low impact way, right up along the shoreline and the vegetation line where the spartina is going to be, and in areas that have been systematically surveyed by other methods for years, when the kayakers go in, we tend to find something that has been missed.

I was a sea kayak guide and I realized that nobody knows the local waters like the paddlers who are paddling those shorelines, spending a lot of time with those eyes on the water.

Liam: Once you’ve identified it; okay, we’ve got a patch of it over here – what do you do with that information.

Rachel: Our volunteers will take coordinates – GPS coordinates for where that plant is located. Then they provide that data for me. That allows me to then take that data and I produce these really cool maps out of it. I share those maps with — sometimes it’s state crews, sometimes it’s county – and sometimes it’s tribal, depending on where you are.

We had some spartina that we located here in the channel earlier in the season. I sent that data and two days later that plant was treated. So it’s really neat to hear them come out and control this stuff right away.

Liam: Has it really gotten to the point where we are literally looking at individual plants?

Rachel: It really has. It’s kind of a hard thing to wrap your head around; is we’re trying to find every single one of these plants. But spartina is that dangerous to the habitats of the Salish Sea.

What’s really cool about the spartina fight, is this is one of the very few invasive species stories that we are actually winning this fight. At peak infestation in the mid-90s, there was thought to be several thousand acres of spartina in Washington State. At this point we have got it down to under about 40 acres.

Liam: Rachel, I guess we’re done looking for spartina for the day; shall we paddle on back to LaConner?

Rachel: Yeah; why don’t we start to cruise on back and enjoy a little bit more time out on the Salish Sea.

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2 Responses to “Cutting the Grass: Rachel Benbrook Takes on Invasive Spartina”

  1. Thank you for having Ms. Benbrook on your program, she was very informative


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