Japanese Knotweed in seed. Photo credit: Vincent Frano
Many of us love a good villain. There’s something cathartic about directing one’s fear, anger, and morbid curiosity at a clear “bad guy,” someone who deserves the negativity we feel towards them. In the black and white world of good vs. bad the heroes and villains are easy to identify and respond to, giving us a sense of instant satisfaction. Since the term “invasive species” was first brought into the public consciousness by Charles Elton in 1958 — in his book The Ecology of Invasion by Animals and Plants — there has been a trend of grouping species into “heroes” and “villains” based on their origins. Native species have become the heroes, the ones to protect and support, while species from distant regions are quick to be labeled the villains to be reviled and destroyed. This is certainly a simple, straightforward way of approaching the movement and interaction of species in a globalized world; it fits neatly into human cultural ideals that prefer such dichotomous thought. However, this dichotomy lacks the nuance and fine detail present in the natural world (which is the world itself) and may actually hinder critical thought and scientific advancements in ecology and conservation. Here I’d like to consider the many sides of the story, inviting in the murky, grey areas so we can begin to approach invasive species with curiosity and open minds.
There is no doubt that species introduced to a novel environment can profoundly impact the ecosystems they enter. I witnessed this to a startling degree while studying in New Zealand for an intensive on ecosystem restoration, indigenous land management, and invasion biology. New Zealand, being a small island nation, has suffered immensely from the impacts of invasive species. The worst offenders are possums (Trichosurus vulpecula), introduced from neighboring Australia; a myriad of European species, including hedgehogs, rats, and weasels; and various plants, including kikuyu grass (Pennisetum clandestinum). Some of these species, like Norway rats (Rattus norvegicus), were introduced accidentally, while others, like kikuyu grass, were introduced intentionally for agricultural and industrial purposes (kikuyu grass was planted for pasture and erosion control). During my studies on the North Island I traveled from Auckland up to the area around Motatau, stopping along the way to visit conservation projects, Maori land stewards, and protected islands. Even in the remote areas around Motatau, where you can see the Milky Way streaked with purple and blue light on clear nights, I was struck by the lack of birdsong.
Hedgehog spotted on a logging road near Motatau - Hedgehogs, introduced to NZ from Europe, are a major threat to kiwis, often destroying nests and eating eggs. Photo credit: Vincent Frano
New Zealand is home to many magnificent and unique species of birds, the most famous being the kiwi (Apteryx spp.). Many of them, kiwis included, have been under immense pressure from introduced species, particularly those introduced by European colonists and their descendants. While staying with a Maori family at their remote homestead, my hosts explained how the forests on their family’s land were once filled with birdsong. Stories shared from their elder family members spoke of the beautiful symphony that could be heard every day in the temperate rainforests and the certainty of hearing the kiwi’s mating call on winter evenings. Today, while the kiwi’s call can still be heard on occasion, the symphony of birds has become a memory. In particular, possums, weasels, hedgehogs, and cats have decimated the island’s population of endemic and native birds. This foreces many avian conservation efforts to move to small, coastal islands where invasive species can be excluded and managed more easily. These island sanctuaries allow visitors to hear the cacophony of birdsongs that once filled the North Island of New Zealand.
Sunset near Motatau - With luck you can hear the kiwi bird’s mating calls on calm Fall and Winter nights. Photo credit: Vincent Frano
Throughout the world there are similar stories of introduced species causing immense and at times irreparable harm to native ecosystems. Predatory animals and dense, fast growing plants — like the species introduced to New Zealand — tend to be the most damaging when introduced to a new region. While we cannot ignore these facts, it is important to consider that what is deemed invasive can be a reflection of the times and what is considered culturally or socially important. In North America, many of us now consider turf grass, earthworms, and honeybees to be a natural part of our gardens. Rarely do we consider that all three of these species (or groups of species, as with earthworms and turf grass) were in fact introduced from other parts of the world.
Before They Were Accepted
Turf grasses were introduced to North America from Europe by colonists for livestock. Photo credit: Vincent Frano
Today honey bees (Apis mellifera) and earthworms (ie. Lumbricus spp., etc.) are particularly lauded as beneficial to the environment, but this wasn’t always the case (and still may not be). When European colonizers first settled in North America they brought plants and animals intentionally for agriculture and unintentionally in ship ballast and cargo. Earthworms arrived, likely unintentionally, and quickly began to transform the landscape by devouring leaf litter and decaying materials. The rapid turnover of decaying matter led to a change in soil composition, increased forest soil erosion, and likely the reduction of native organisms adapted to a worm-free ecosystem. In addition to worms, colonists brought honey bees which indigenous peoples dubbed “white man’s flies” because the bees signaled where colonists had settled. Finally, turf grass (ie. Poa pratensis, etc.) was introduced by colonists to replace native prairie and bunching grasses which they deemed poor feed for their livestock and to recreate the lawn-like environments they were familiar with in England and Northern Europe. Together, along with many other plants and animals introduced by colonists, these species helped transform North America into the ecosystems we are familiar with today. Indeed, the North America known to pre-Columbian indigenous peoples would seem foreign to those of us who live here today. We now coexist with numerous species from Europe, Asia, and Africa, many of which are not considered invasive even though they are not native.
In the United States, turf grass covers approximately 2% of the total land (based on a 2005 NASA study). Although turf grass excludes native plant species, fragments habitat, and reduces native species biodiversity where it is dominant in the landscape, this group of species is not considered invasive. Aside from numerous articles describing how to ditch your lawn for easy to care for regionally native plants, you’d be hard pressed to find a campaign against invasive turf grass that resembles those against japanese knotweed or garlic mustard. For species labeled invasive, there is often an aggressive and pesticide heavy management plan with a goal of total (or near total) eradication. So why do we tolerate introduced turf grass when it occupies 40 million acres of land in the US, far more than the land occupied by our biggest crops like wheat and cotton?
Similarly, honey bees are considered to be an important insect and have become the poster child of many conservation efforts. The call to “Save the Bees” has tended to focus on honey bees, leading people to consider bee keeping and helping honey bees to be beneficial to the local environment. Unfortunately this is far from the case. Honey bees are incredibly abundant worldwide. Thanks to humans who keep them for honey and their pollination services for agricultural crops, there are an estimated 1 billion honey bees in the US and Canada alone! The bees whose populations are declining are native bees. Native bees have received far less public attention and are not well understood or recognized by the general population. Furthermore, high densities of honey bee populations have been associated with increased competition with native bees, resulting in a decline (PDF) in native species. If honey bees are out-competing native bees – whose populations are struggling – then why do we tolerate them?
Right: Introduced Honey Bee on a native Goldenrod flower (both taken in Massachusetts, USA) Photo credit: Vincent Frano
The Human Impact
Moving in a Changing World
Critiquing the System
Right: Native Jewelweed, one of several native species with aggressive spreading habits, allowing them to form dense colonies. Photo credits: Vincent Frano
Keeping in mind that things may change, here is my approach to invasive species as I understand the issue today:
Avoid planting highly aggressive plants that are known to outcompete native plants or cause major disruptions in the landscape.
These plants are typically listed as “invasive species” by the USDA and are extremely difficult or impossible to remove once established. These may include: Japanese Knotweed, Oriental Bittersweet, and Japanese Barberry. These plants generally have extensive root systems with deep tap roots that cannot be fully removed once the plant is established. They are also capable of generating roots from cut stems and sometimes leaves.
Manage aggressive plants (like the ones named above).
Pulling young plants before they have a chance to establish. Leave pulled plants in a location where their roots will dry out and cannot make contact with the ground (such as hanging them in a tree’s branches). Cut back established plants that encroach on plants or landscapes you wish to maintain. But know that you will not be able to eradicate established colonies (even when using large machinery and glyphosate, there is no guarantee of eradication of species like Oriental Bittersweet, Japanese Knotweed, etc.) and focus your removal efforts on areas where aggressive species impact landscapes that are actively used or managed or where sensitive species are affected.
Don’t stress about non-native species in environments that are heavily impacted by certain human activities.
This is where the nuances come in, so discretion and education around local landscapes and plants is beneficial. Abandoned lots, industrial yards, roadways, and so on are hotspots for many aggressive species that are considered invasive. However, these environments are often difficult for any plant to live in. The plants that thrive in these areas, which often have high levels of soil contaminants, are the ones adapted to the harshest environments – Japanese Knotweed, for example, is adapted to colonizing volcanic areas following an eruption. These aggressive plants, while not native, can stabilize soil and some even take up soil contaminants. While native plants can do this as well, non-native plants may be the only species present in an anthropogenic environment. Unless there’s a plan to replace every non-native with a native (ie. swap the knotweed for goldenrod), it’s ultimately counterintuitive to remove these plants from the landscape.
Consider the ecosystem you are planting in and whether the plants you’re choosing could pose a risk to the native ecosystem.
If you want to grow a non-native plant, look for plants that a) are likely to die back annually in your growing zone b) are not prolific seed spreaders or highly attractive to seed spreading animals (ie. have many delicious fruits) c) do not spread by runners or suckers and d) do not easily propagate from root cuttings. The last one is really important, as these plants can regrow even from a very small portion of root or rhizome, making them difficult to remove once planted.
Plant aggressive spreaders in pots that are not allowed to make contact with the soil.
These plants may spread by root division, sucker, or runner. Remember to cover the drainage hole so roots don’t escape into the soil.
Remove spent flowers of plants that produce a lot of seeds or fruits.
This will prevent the plant from reproducing, but you can still enjoy the blooms.
Small Victories' Current Approach
A diverse meadow of native and non-native plants growing in New England. Photo credit: Vincent Frano
As the co-owner of a plantable stationery company that sells to a global market, the issue of invasive/non-native plants is high in my awareness. We occasionally receive inquiries about our cards and the seeds contained in them, typically regarding concerns over the plants being invasive. This is a matter we do take very seriously, but it’s one we also approach from a broad perspective that never settles on a single “right” or “wrong,” acknowledging that there is always room for change in an ever changing world. Our cards contain common garden plants across the globe.
While all native seeds would be great, here’s why our cards contain a mix of seed species:
- We sell globally and it is impossible to have seeds native to every region where we sell cards.
- Our paper makers are limited to what seeds are approved by the USDA and the Canadian and EU agricultural regulatory organizations. We have requested alternative seed mixes in the past, however, the seeds requested were not approved by these organizations despite being more broadly native to the Northern Hemisphere. Rest assured that the seeds in our cards are tested for purity and they are all non-GMO.
- Not all non-native species are “invasive.” If we planted only native plants, we wouldn’t have access to most fruits, vegetables, and garden plants we think of as important to our lives. This list includes: apples, roses, wheat, marigolds, and many more!
I acknowledge that this is far from perfect, and in an ideal world we would be able to offer cards with seeds specific to the regions where people want to send or buy cards. Perhaps one day we’ll get there, but for now this is what we’re able to do. Nevertheless, our cards primarily contain seeds of common garden plants, such as Snapdragon or Basil. While these may not be native to North America, they are ubiquitous in North American gardens and are not considered invasive, noxious, or particularly aggressive. Because of this, I do not believe that our cards are negatively impacting ecosystems any more than a well thought out organic home garden does. Of course, as I mentioned earlier, it’s important to use discretion when choosing what to plant in your region. So, if you are concerned about planting a particular seed (say, Sweet Alyssum), then it may be a good idea to purchase one of our Brights cards, which are printed on paper with a mixture of herb seeds. All of our cards can also be grown in a pot or planter, so there’s no worry about the plants escaping the garden.
In the end, we are all living in an incredibly complex world that’s ever changing. We humans have certainly learned a lot about how the world we live in works, but we’re never going to have it all figured out. And even when we think we’ve got something figured out, there can be new information learned or different approaches that completely upend what we thought we knew. All this means that, in my opinion, we need to approach life with an open mind that’s curious and willing to adapt and shift over time.
I started this journey with invasive species nearly ten years ago and I have changed my views or adapted my approaches many times over. I began in that black and white world of all or nothing, ripping up every invasive plant I saw and battling them with a vengeance. As I immersed myself more in learning about plants, ecosystems, and human-ecosystem interactions I began to shift more into the “grey area.” Today I still manage non-native plants around my home, removing them as needed, but I’ve ended the all out war. On a planet that is suffering greatly from strictly human activities (ones that don’t involve other species) it feels counterproductive to wage war on the living things who are simply being themselves. Instead I think about the ways that we humans can work together to retell an old story: where humans are part of the ecosystem and we, like all living things, must exist in a balance. A balance that is ever shifting with time. Perhaps that’s all that “invasive species” are: a sign of a world off balance – and here we all are killing the messengers without really listening to what they have to say.
Other articles you may like: Invasive Plant Medicine, The Story Behind the Cards - Animal & Plant Companions
About the author:
Vincent Frano is an avid student of nature. He is trained as an herbalist with over 10 years of experience in European traditions with knowledge of Ayurvedic and North American herbs. He holds a BS in Sustainable Horticulture from the University of Massachusetts, Amherst where he focused on herbal medicines, native plants, invasive species, and ecosystem restoration. Vincent is the co-founder of Small Victories and is the lead illustrator for Small Victories' products.
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