Invasive Plants: Interview With Ann Smreciu
Ann Smreciu of Wild Rose Consulting Inc. received a 2017 Emerald award for her long time work in native plant land restoration. She is an expert on Alberta native plants and has worked for many years on using them in disturbed land restoration. Through this work, she has also had experience with the problems caused by various invasive species. I spoke with Ann on February 16th to learn more about her work and how it relates to native and invasive plants here in Alberta.
Haley: Hi Ann, can you tell me a bit about your work?
Ann: For the last 40 years I’ve been working in restoration and reclamation, and particularly in the replacement of native plant communities, and rather than trying to just revegetate with anything, which is sort of what was done in the past, we’re trying to put in native plants from that region to recreate or at least create functioning ecosystems that can be self-sustaining. Often in the past what they would do in reclamation is put in a number of plants in an area, and most of them were introduced because it was very difficult to get native plants, and then they would try and walk away but of course those plants would die or become a problem, in some cases invasive. We’re now trying to make sure that we’re using native plants and re-creating something that’s self-sustaining.
Haley: How have invasive plants directly impacted work that you’ve done?
Ann: In the past, reclamation didn’t use native plants. They used a lot of non-natives and a lot of plants that are used for forage and in rangeland, so there are things like smooth brome which is agricultural and has been developed for specific purposes; a lot of forage work and so on, but because we were using those in the past, it’s very difficult to get rid of them and try to re-establish what should be there. If you get something like smooth brome into a site that you’re going to try and reclaim, it’s a problem, and it’s everywhere. It’s not considered a weed in the province but it certainly is invasive.
There are no limitations on it because farmers will use it and rangeland managers still use it, but that’s a problem. In the past, before they were using native plants, they were using the plants that they could get their hands on, and of course, a big thing was trying to build soil. They thought that legumes; plants in the pea family, would be a really good idea because they take nitrogen from the air and fix it. So they started introducing things like clover, sweet clover, and some of the milk vetches, and used those because they produce really well and are great for erosion control. Again, however, they’re not native so they don’t encourage the native microflora and they also discourage tree growth or other plant growth. If you try and get those established and then start to try and put other plants in, it doesn’t work.
There aren’t many places that I work where we don’t have a problem with clover or sweet clover or one of those legumes that have been used for so long. There are also invasive plants that have been introduced accidentally by horticultural trade. For instance, down in southern Alberta there’s a huge problem with Baby’s Breath, and Baby’s Breath was introduced, as far as I know, into some of the cemeteries. And it has just expanded. In fact there are large programs now to get rid of it. What happens is that it dries out, breaks off and then tumbles across the prairies and spreads its seeds. It’s a problem because it takes the place of something else in the environment. Rather than a native plant, that’s what you’ll get.
Canada Thistle is another one. You’ll find it everywhere and it’s become very invasive. It’s a huge problem in reclamation. If it gets in there, at this point in time we don’t have a really good way of getting rid of it other than chemical which is a continuing thing; you have to keep at it. And throwing chemicals around is-
Haley: Not always what you want
Ann: Exactly. So, in terms of revegetating these disturbed areas after they’ve done all of the hydrology and the soil work, we have to be very careful with the invasive plants because if they get in we have a problem.
We see more and more invasive plants as we get up North these days. With more and more traffic up there, there are more weeds coming in and invading those areas. When there was a single mine it was one thing, but now that there are several you’ll have more traffic and people moving things around. Up in the northwestern part of the province, I know that there are abandoned well sites that are just covered in dandelions. And they are, as opposed to what people are saying, an invasive species. They don’t allow for the re-establishment of the native vegetation. I know that people don’t call them weeds anymore, I think the city has stopped calling them weeds, but they are.
The other thing is that when these plants get into these sites they are extremely dominant and just use up all the niches. They’re very effective at using up all the nutrients, the light, and space so that other plants can’t establish. Certainly part of revegetation is trying to get a certain number of plants in there and then allowing things to colonize so that you have a natural succession. A lot of those plants don’t come in because of the weed problems. If we want to put trees or shrubs into an area where we’re trying to reclaim an old site, how do we keep weeds out? There’s lots of work being done on mulches and various mechanical and chemical ways of maintaining a space for that plant to grow until it gets to a certain height because once it’s a certain height it has a bit of a competitive advantage. But in the meantime we don’t have the right soil microbiota and so on. In a forest, there are not just trees but a lot of the understory plants that are truly connected, and I mean physically connected and there’s a movement of nutrients. You’re not getting that on these sites because these invasive plants don’t participate in that kind of function.
Haley: So there’s a direct answer to another question I had. I think a lot of people ask what’s the point of having native plants? Some people think of it as “oh we just like them because-”
Ann: Because they’re pretty, or something.
Haley: But that’s something real right there.
Ann: Soil building and the natural microflora. The big problem is if you don’t have the native plants you’re decreasing biodiversity in an area and decreased biodiversity means less resilience. So in terms of any major changes that come through like fire and so on, you don’t have the ability to recover. We’re looking at climate change, so as the planet warms up (certainly that’s what’s happening here) we need to be able to be adaptive and if something came along for instance right now and just wiped out all the dandelions there would be huge bare areas and we’d have erosion problems. So you need diversity.
If the grasses are there and they move to forbs and trees and shrubs; in all of those groups they’re dropping their seeds onto the ground and if a fire came through succession would be moved backward but it would start again because you’ve got the seed bank there. Whereas if you don’t have the seed bank and all you’ve got are these species (and some of these are not resilient), it becomes a monoculture. Also, a loss of wildlife habitat. It affects things like recreation, as well as different groups of people such as First Nations who use those plants. And economically, a lot of these plants I’ve been talking about are agricultural in origin, but some of them are not. Some such as Tansy which is starting to take over hugely in some areas, they become agricultural problems as well as you start getting loss of yield. It’s economic, cultural, biological. There are all kinds of reasons for it. And if we don’t have our trees and we can’t grow back our forests, it’s going to change the weather and climate cycle as well, so it’s huge.