ST: Let’s start with the title, “Beyond the War on Invasive Species.” Who is waging this war, and why, and how did you find yourself, unwittingly, on its front lines?



TO: Invasive plant and animal species are considered one of the primary threats to ecological integrity and global biodiversity today, thus many people consider their eradication a top priority. However, though invasive species may appear troublesome, the ecological processes that underlie their proliferation (many of which we are directly responsible for) are much more concerning, but are not necessarily as easily addressed. For example, an invasive plant like salt cedar growing along the Colorado River appears to be displacing native vegetation, but this view focuses on the plant itself as a driver of ecological change, rather than piecing together the complex dynamics of water use and allocation on the river. But when you do that analysis, its clear that only a plant like salt cedar would survive there. The so-called ‘war on invasive species’ is one that is narrowly focused on organisms rather than acknowledging changed and changing ecosystems.

Many of the people involved in restoration care deeply about preserving diverse and functional ecosystems, but when restoration focuses on removing invasive species without looking at why they are there in the first place, it is never going to achieve meaningful results, especially over time. I realized this when I got a job working in wetland restoration, and saw that the primary concern was whether invasive species were present rather than the larger picture of impaired wetland systems in the valley where I live (which historically was mostly wetlands before they were drained and diverted for agriculture and housing development). When I saw that the concern about invasive species was so strong as to cause well-educated ecologists to turn to the use of herbicide, I was shocked, and the organic farmer and Permaculture in me started to think about the situation differently.

ST: Why have we been led to believe that all invasives are bad and must be eradicated at all costs? But, what are those costs to our ecology, our health, and even our economy?

TO: The concept that there are ‘bad actors’ in nature that can be controlled with the addition of chemicals is prevalent in the conventional agriculture model. ‘Pests’ like insects, non-crop plants (‘weeds’), and diseases are treated with a vast array of synthetic insecticides, herbicides, fungicides, and other biocides with the belief that removing these organisms is a necessary part of growing food. However, as many organic farmers know, the prevalence of any of these organisms is not necessarily due to the fact that the ‘pest’ is present on the farm, but that it finds suitable habitat there – whether that be stressed plants susceptible to disease, low organic matter, or overtilled soil. None of these conditions are solved by the addition of pesticides, thus the concept that they can be sprayed out of existence is irrational from a whole systems perspective. However, strong corporate interests reap huge financial returns from marketing this very concept, and these same interests are at work in the field of ecological restoration and have promoted the notion that invasive species are ‘bad actors’ in parks, wetlands, forests, and other natural areas.

When it comes to food, many people are aware of the potential dangers of pesticide exposure and choose to purchase organically grown products. I don’t think many people are aware that some organizations involved in ecological restoration and maintenance of public areas like parks use the same chemicals – including glyphosate, 2,4-D, and Imazapyr – in the hopes of controlling plants and animals considered invasive. These chemicals have serious health effects on humans and other creatures, and the fact that they are used as a means to ‘restore’ ecosystems requires close scrutiny. Ecological restoration should be grounded in holistic, ecologically rational practices instead of a conventionally-based, pesticide industry-sponsored approach.



ST: In his foreword, David Holmgren writes, “In the process of asking the questions about how best to restore nature, Orion exposes a deep ethical corruption at the heart of both ecological science and the environmental movement.” What is this ethical corruption, and what are the questions that we should all be asking as it relates to restoration?



TO: The “ethical corruption” that Holmgren describes is the dangerous trend in the science of invasion and restoration ecology to narrowly focus on restoration as a practice of attempting to return certain ecosystems to an idealized former state. This concept paints invasive and novel organisms as disruptive to ecosystems, and tends to miss the bigger picture of how ecosystems have changed and are constantly changing in response to human and non-human impacts upon them. That large conservation and restoration organizations like The Nature Conservancy are allied with pesticide manufacturers like Monsanto, which have essentially manufactured the war on invasive species for their own financial benefit, is something that we have to think about very closely. This approach for managing species invasions does little to restore ecological functionality, especially on a larger scale.

Restoration as a practice also tends to focus efforts on certain landscapes and not others – restoration is generally not part of the planning process of planting an 8,000 acre field of soybeans, clear cutting a forest for plywood, planning a housing development, or adding lanes to a highway. However, ecosystem services and the organisms they support are heavily affected by agriculture, forestry, and urban/suburban development, and the way that these activities are carried out deserve at least as much scrutiny for their role in degrading ecological function as do novel species.

Invasive species are perhaps an easy target for identifying changing ecosystems, and I think many people would rather ecosystems stay the same. We mourn the loss of biodiversity and habitat destruction, but can feel powerless to do anything about it. That restoration as a practice has become so focused on eliminating invasive species, while not addressing or working on changing standard operating procedures of world biodiversity loss – agriculture, forestry, urban/suburban development, etc. - means that “restoration” as we know it is misguided. If we desire landscapes rich with diverse native species, then we have to design our lives in ways that meet this goal.



ST: Why has this habitat restoration model lasted for so long, especially given what we know about some of the chemicals that are contained in herbicides? Not to mention, the use of fossil fuels to power dump trucks, bulldozers, and other land-clearing equipment?

TO: I think the marketing undertaken by pesticide manufacturers has been very effective in constructing the concept of invasive species, as well as in convincing people that herbicides are safe and benign substances, and necessary for the restoration of native plant communities. The eradication ideology knows no bounds in terms of the tools that are put to use in order to achieve the narrow and short-sighted goals of invasive species removal. I believe many people in the industry are uncomfortable with these practices, and question their efficacy, but still believe that invasive species are ‘bad’ and must be removed at all costs. When placed into a larger context, it becomes apparent that there is more to the story of invasive species, and the conventional approach to restoration starts to seem inadequate at best.



ST: Do you ever find it necessary to remove an invasive plant, and if so, what is your approach – both in terms of removing the plant, and how you manage the overall ecosystem?

TO: Yes, I deal with invasive species all the time, and remove them as part of a larger management strategy on my farm. I have several large patches of Himalayan Blackberry on my site, and am slowly transforming them into more productive and diverse plantings. The largest one has been home to two rotations of pigs, and this winter after noticing that they had eaten a good portion of the roots, we terraced the area, planted blueberries, and sowed a thick perennial clover cover crop beneath the blueberry plants. There are still a few canes resprouting (down from several thousand), but these are easily clipped or pulled out. So, we mimicked the ecological functions that the blackberry canes were serving – slope stabilization, erosion control, bird habitat, nectar and pollen for pollinators, and fruit resources for birds and mammals – with our own more diverse and productive mixture of plants. I take a similar approach with Scotch Broom – use its prolific nitrogen-rich biomass as mulch for fruit and nut trees. Its proliferation is a sign that the ecosystem where it grows is tending towards forest, and we can hasten and direct that process towards diverse and abundant ends.

Anytime I plan on removing an invasive species, I think less about taking it away, and more about what I can add to the system that accomplishes what the ‘invader’ is doing in a manner that makes the ecosystem even more resilient, diverse, and productive. In some cases, such as in more difficult to manage areas like waterways, invasive species are really the best things going in heavily degraded ecosystems. Consider how zebra mussels are removing PCBS, heavy metals, and antibiotic-resistant bacteria from the water of the Great Lakes. Native mussels can’t survive in those conditions, so we should be glad that something is there doing it. In this case, I wouldn’t seek to remove the mussels, but consider how I could enhance their effectiveness so that over time, the lakes can once again host a wide array of diverse aquatic organisms.



ST: How does permaculture design thinking apply in the context of habitat restoration? Isn’t it mostly used for farming and gardening?

TO: Permaculture is often thought of in terms of being an alternative farming or gardening system, when in fact it is a way of thinking in terms of whole systems. Holistic concepts – like companion planting and growing nitrogen fixers to fertilize your crops instead of buying fertilizer - are easy to see and apply in a garden setting, and those same kinds of ideas can (and should) be applied in any context. It’s a practice of seeing interconnections, and thinking like an ecosystem, understanding feedback processes, and learning more about the process of succession. When I started working in the restoration field, I was surprised at how intensely people feel that invasive species are ruining ecosystems, because I felt like I could see the exact opposite perspective – that they are in fact in the right place at the right time given what the ecological conditions on the ground looked like. So for me, applying a Permaculture-based approach to invasive species gave me a sense of how to approach restoration in a new way.

This brings up an important point about invasive species – they aren’t necessarily ‘good’ just as they aren’t necessarily ‘bad.’ From an ecological perspective, they are making the best out of the available situation. Native plants also have very desirable qualities, but if they are unable to thrive, and it appears that an invasive species is displacing them, then we have to look at the ecological conditions that are facilitating the invasion, and work from there if we wish to steer the ecosystem toward more productive ends.



ST: Can you provide an example of common invasive species? And, what are their benefits to the soil, and even human, health?

TO: In the U.S., some common invasive species include kudzu, Japanese knotweed, and spotted knapweed. Each of these has unique features that are contributing to improving ecological functionality (even though it might not appear that way at first). Kudzu, a perennial nitrogen fixing vine, is edible—goats and cows can eat the high protein leaves, the root (also known as arrowroot) is a common ingredient used to thicken soups and gluten-free breads, it’s medicinal, bees relish its prolific flowers, and its massive roots stabilize erosion-prone slopes. Japanese knotweed grows along highly eroded stream channels. Its massive root systems stabilize soil. Pollinators of all kinds feed on its prolific nectar, and the new shoots are edible. An extract from its roots is a critical part of the herbal treatment of Lyme Disease. It also produces ample biomass that can be used for compost and mulch. Spotted knapweed is another incredible nectar and pollen resource for pollinators. Its root-based mycorrhizal associates accumulate phosphorous, a critical nutrient for plant growth known to be in short supply worldwide.

So, though these plants are vilified, they each have characteristics that can be considered beneficial to both people and the ecosystems where they are found. These attributes should be put to use – grazing goats and cows on kudzu in the southeastern U.S. rather than feeding them alfalfa grown in California’s deserts would be a great way to start a Permaculture-type restoration plan. In the process, the landscape where kudzu once grew could be replanted to native hardwoods like hickory and black walnut, and the young trees would benefit from the prodigious nitrogen made available by the kudzu roots. If these types of activities—small-scale, locally adapted, and based in holistic concepts—happened on a large enough scale, even the ecosystem where alfalfa grows in southern California could be restored to greater diversity as demand for products from far away places declines.



ST: You mention that we often focus on invasives as the “problem,” when, in fact, they should be seen as a symptom. What signals should we look for to determine why an invasive is proliferating, and what that might mean for the health of the overall ecosystem?

TO: Every organism needs the right conditions to thrive, including both native and invasive species. So, if native species are failing to thrive, and invasive species appear to be displacing them, it is critical to look first at the conditions on the ground. Invasive species don’t have special powers and aren’t inherently malignant. From an ecological perspective, they are exploiting available niches. This is one of the main reasons that eradication doesn’t work – because unless the niches are changed in ways that encourage native or other desired species to flourish, eradicating invasive species achieves no measureable ecological benefit.

It is also critical to recognize that the effects of climate change – from drought to storms to species migration and extinctions – are transforming ecosystems in ways that we may not be able to fully understand at this time. Invasive species may be better adapted to changes on this scale. Research from Oregon State University showed that the invasive Himalayan Blackberry grows four times faster than species of native blackberry in high carbon dioxide conditions. From an ecological perspective, as global CO2 levels continue to rise, we are creating the perfect niche for this invasive species to thrive. Invasive species may be anchors of future ecosystems that are emerging as the effects of climate change intensify.



ST: Your book offers a bold new perspective, but you admit that the biggest challenge to taking this new approach to managing invasives is “thinking differently.” What are some of the first steps people should take to make that switch?

TO: When you see an invasive species, instead of automatically thinking of its ‘negative’ qualities, think about what it is doing in the ecosystem where it is found. Do pollinators use it? Is it controlling erosion? Start thinking less in terms of the organism and more in terms of the ecosystem that supports it. What has changed in recent history that may contribute to the proliferation of invasive species? Critical to this understanding is an acknowledgement of how indigenous land management shaped and structured ecosystems—including plant and animal population diversity and abundance—and that lack of this management has facilitated invasion processes even in areas considered ‘natural’ or ‘wild.’ Invasive species are directly related to changes in land management, from highly degraded to ecosystems to seemingly ‘pristine’ areas, and learning more about the cultural history of ecosystem management is critical to seeing invasion processes as a predictable outcome of the type and scale of these changes.

Restoration should start at home, with every facet of our lives linked to practices that are restoring ecosystems. At this point, many of the things that we take for granted in modern life – from the wood framing our houses to the food on grocery store shelves – have an ecological story to tell that is generally not one of increasing biological diversity. And, invasive species are often found in these types of degraded ecosystems, from overgrazed rangelands, to polluted lakes, to eroded streambanks. Taking the opportunity to consider how these species are acting in their own ways to improve ecological functionality is another powerful aspect of Permaculture design – it provides tools for creating integrated systems of food production, water management, shelter provision, and habitat enhancement that can help meet the goals of incorporating ecologically restorative practices into our day-to-day lives.