It’s Invasive Species Awareness Week, and although every week is unofficially Invasive Species Awareness Week here at Invasivore.org, we have decided to treat our readers to a special entrée discussing the invasion process, management of invasions, and the role we envision for invasivore.org within this framework. Ultimately, the true purpose of eating invasive species is increasing awareness; we encourage the lifestyle and political choices needed to prevent species introductions.
Invasive species can be aesthetically displeasing, economically disruptive, and are a primary driver of global loss of biodiversity. Yet biological invasions are also impressive in a way- it seems counterintuitive that a species which evolved in one ecosystem could become so dangerously prosperous on the other side of the globe, despite encountering novel predators, competitors, diseases, and climates. Invasions have occurred into, and out of, every type of habitat, and invaders hail from every branch of the tree of life. All invasions are similar however, not by type, but by process. Our understanding of this process provides a framework for studying and responding to harmful species invasions.
Every biological invasion begins with a species entering into a Pathway. Entrance into a pathway may be deliberate, for example, a fish caught from its native river and shipped as part of the aquarium trade. Pathways can also be unintentional, such as some plant having its seeds bundled with a shipment of wheat. Or an insect burrowed into a tree, stowed away in a shipment of lumber.
Once they have entered a pathway, potentially invasive species must then survive Transport from their native range into new ecosystems. Not all species survive, and, in fact, each step in the biological invasion process can be viewed as a series of filters or hurdles a potential invader must pass before achieving invasive status (conveyed in the figure by decreasing arrow widths between each step). Transport once posed a serious barrier to species invasions, but as globalization brings the world closer, more species are surviving shorter trips to be Released in new locations.
Should species survive transport and release, a self-sustaining population may Establish. Again, not all released species establish populations. Indeed most do not, succumbing to climate, predators, competitors, disease, and even intraspecific loneliness. Populations that do establish can then Spread beyond the site of their initial introduction. Once species establish and spread, it becomes increasingly likely that we notice ecological and economic Impacts of invasion.
Just as biological invasion can be depicted as a stepwise process from Pathway to Impact, so too are the management options for the control of biological invasions. Different management options target different steps in the process, so it is essential that we consider the stage of the invasion before acting.
The first and best management option is Prevention. Economic models have shown that, it is far cheaper to prevent an invasion from beginning than to respond to invasive species once they are established. Public education is essential to preventing the movement of invasive species. Knowledge of potentially invasive species and their impacts may dissuade people from introducing foreign organisms and provide the political will to meet the challenge of invasive specie.
If prevention fails, then management priorities shift to Early Detection and Rapid Response. A small number of introduced organisms are a lot easier to clean up than an entrenched population. Vigilant monitoring efforts are key and public awareness is essential, as a knowledgeable public will sound the alarm when potentially invasive species are encountered.
Once populations of invasive species become established, management options become limited, and costly. For this stage in the invasion process, eradication programs are sometimes an option, and programs to Control the Spread of the species are urgent. Such programs include quarantining of invaded habitats as well as public education to prevent people from intentionally or inadvertently moving species beyond the site of their initial introduction.
If all else fails- if, despite our best efforts, species enter a pathway, become introduced and establish in a new habitat, and efforts to control further spread fail- then the remaining management option is Adaptation. Adaptation involves adjusting human behavior to accept the impacts associated with invasive species. For most known invasions, this is the only option that remains.
Why Invasivory? Awareness is the ultimate goal
So how does invasivory fit into the invasion process and management framework described above? At invasivore.org, we propose that eating invasive species contributes at every step of the process. We hope we can tap into two types of hunger- for food and for knowledge- to provide a two-pronged approach to controlling biological invasions.
The first and most important component of the invasivore response is Awareness. By providing recipes alongside other important information about invasive species, we support Lifestyle Choices and the Political Will to take action against invasive species. In this way, we move from merely responding to invasions under way, towards preventing them.
An informed invasivore will always be on the lookout for new invasions. Invasivores are Citizen Monitors of areas of high invasion risk, often where other invaders are already established, ready to sound the alarm -or dinner bell. Invasivores provide early detection, enabling and providing rapid response.
Eating invasive species may also contribute to controlling the spread and limit the impacts of invasive species through Direct Population Reduction. Overhunting has lead to the extinction or near extinction of many species such as the passenger pigeon or the American bison, so why not invasive species? Unfortunately, the biological traits of invasive species tend to be quite different from those of species previously susceptible to extirpation. Invasive species typically have high growth rates, mature early, have escaped their native enemies and diseases, and have wide dietary breadth and environmental tolerances while the traits of eradicable species are the polar opposite. While direct harvest is the poster child of the invasivore movement, as with all interventions near the end of the invasion process, it is one of the least effective.
Lastly, when we are forced to accept an invasive species, eating them can Reduce the Economic Burden of this adaptation. Harvest and use or sale of an invasive species may at least partially recoup some of the monetary losses suffered from the loss of native biodiversity. Of course, adaptation is the least satisfying option, but perhaps better than nothing.
To these ends, what’s really important to us at invasivore.org is to inform and discuss biological invasions in the most palatable manner possible. Our recipes aren’t just food; they’re also food for thought. Hidden within is a lot of other delicious information on the study of biological invasions. This information is useful in making informed choices to prevent species introductions. So let’s learn together and put invasive species in their place- in their native range or on our plates!