Could Invasive Species be the Future of Sustainable Dining?

While the rapid expansion of invasive species is challenging ecological balance, an emerging culinary trend offers a promising yet controversial solution.

In a world dealing with the complexities of ecological imbalance, there is growing concern about the rapid expansion of introduced non-native species, otherwise known as ‘invasives’.¹ With global climate change and habitat alteration accelerating the spread and proliferation of exotic species, plants and animals, like the prickly pear in the Mediterranean or the Asian carp in North America, are spreading far outside their natural range.

But there’s a unique and somewhat controversial solution that is gaining traction: viewing invasive species as food. If managed well, this solution could be a win-win to manage both their populations and mitigate their impact on ecosystems.

The rise of invasive species in a changing world

Invasive species are any living organisms – plants, fungi, or animals – both marine and terrestrial, that, once brought outside of their native habitat range, pose significant threats to the local biodiversity. Unlike native species that have slowly adapted to their local environments over thousands of years and play a crucial role in balancing their local ecosystems, invasive species often exhibit rapid adaptive capabilities and aggressive colonisation strategies when they enter new habitats. This competitive edge is largely due to the lack of their natural predators and ecological barriers that would normally keep them in balance in their own native ecosystems.

Once embedded in a new ecosystem, the consequences of invasive species are profound. They can alter soil chemistry, reduce biodiversity, and disrupt food webs, ultimately leading to significant changes in the structure and function of entire ecosystems.¹ A good example of this issue is seen with the invasive rabbitfish in the Mediterranean Sea. These fish, originally from warmer waters, have adapted to the Mediterranean ecosystem, overgrazing on the native vegetation and creating barren underwater landscapes devoid of life, which ultimately caused a 40% reduction in the numbers of native species in some areas of the basin.²⁵

While there are a number of causes for invasives finding their way into other habitats, this complex issue is deeply connected to climate change and the impact of human activities on natural habitats.

Rising temperatures 

As global temperatures rise, many regions experience altered weather patterns, creating new ecological niches ripe for invasion. For instance, warmer temperatures can enable exotic species to survive in previously inhospitable climates.² One example is the tropicalisation of the Mediterranean Sea due to increasingly warmer sea temperatures, which has led to an explosion in non-indigenous marine species - such as the Pacific cupped oyster, the nomad jellyfish and the Japanese carpet shell. The influx of these species has not only affected marine ecosystems and native species, but also the fishing communities depending on them.^3,4,5

Both Rabbitfish and Lionfish are invasive in the mediterranean.

Human actions 

Human activities, such as urbanisation, deforestation, and the creation of transportation networks, can further cultivate fertile ground for invasives to flourish. The mechanism is simple: these activities often lead to fragmented or disrupted habitats that can hinder natural processes like nutrient cycling, food webs and seed dispersal. When these habitats are altered, the highly specialised native species they hold find themselves under stress and can struggle to compete with invasive species over the same vital resources, such as food, water, light, and space. Fragmented and disturbed habitats become hotspots for invaders to establish and thrive, outcompeting and displacing native flora, fauna and funga.⁶

Global trade and the spread of invasives

Considering the extensive changes to global climates and habitats over the past century, it's unsurprising that the last few decades have seen a marked increase in invasive species worldwide. This phenomenon has drastically accelerated from the mid-20th century, following the advent of the global trade market.⁷

Our actions, whether through the pet trade, shipping practices, or tourism, have facilitated the transport and establishment of these species worldwide. 

The voyages of early explorers and botanists were critical in the initial stages of spreading invasive species. Motivated by the pursuit of scientific knowledge, colonial interests, or botanical exuberance, they frequently transported diverse plant and animal species across continents. Botanical gardens, in their quest for collection and exhibition, sometimes acted as hubs for acclimatising non-native species, leading to their unintentional release into new environments.⁸

In modern times, the global pet trade represents a significant vector for the introduction of non-native species. Exotic pets, once a symbol of status or fascination, have on numerous occasions been released or escaped into the wild, establishing invasive populations. For instance, the release of pet snakes and reptiles in Florida has led to ecological disruptions due to their predatory nature and lack of natural enemies.¹⁰ A more familiar example is the common goldfish. Originally kept as pets, their voracious appetite allows them to out-compete native species for resources when dumped into natural waterways.⁹

Tourism also plays a role in the spread of invasive species. Tourists, often accidentally, transport organisms in their luggage or clothing, leading to the introduction of species in new environments.¹¹ On the ocean, tourist cruise ships travelling between countries and coasts can also carry invasive marine species in the ballast water, presenting real risks to new marine ecosystems if ballast water is not correctly treated or discharged in another region.

Sometimes, even actions intended to benefit the environment inadvertently lead to the spread of these species. For example, governmental measures like introducing exotic plant species for soil erosion control or agricultural enhancement can disrupt local ecosystems. Similarly, using certain species for biological control of agricultural pests - such as using cane toads (Bufo marinus) in Australia to manage beetles - can eventually backfire, leading to striking ecological consequences once these introduced species become invasive.¹²

Making the best of a bad situation

The economic impact of invasive species is significant – from the costs associated with lost agricultural productivity and control measures to the damage to native ecosystems.^13,14 On top of that, invasive species can profoundly affect human health, either directly through the spread of diseases or indirectly by impacting food security and livelihoods.^15,16

But conservation biologist and author Joe Roman offers a new approach to invasion management: invasivorism, the practice of consuming invasive species to reduce their harmful impact on ecosystems. Born in the United States, this movement has gained momentum in various regions where invasive species are increasingly appearing on restaurant menus. The concept is straightforward: by viewing invasive species as food resources, we could potentially reduce their numbers and mitigate their impact on native ecosystems. While seemingly novel, there are several potential benefits to this approach.

Eat the Invaders provides guidance around harvesting and cooking with invasive species. Sow Thistle, pictured here, is invasive to the US and Canada.Less bitter than dandelion, sow thistle leaves are said to be a good source of vitamins A and C, thiamine, riboflavin, niacin, calcium, phosphorus, and iron. Photo by Arterra via Getty Images.

First, it could represent the most economically convenient approach to biological control. In contrast to traditional methods, which normally have high costs and do not generate clear economic benefits, invasivorism leverages existing culinary markets to target invasive species, creating an opportunity for economic gain while incentivising the harvest of invasive species.^17,18

Second, it contributes to diet diversification in an era where our diet almost totally relies on a handful of overexploited natural resources.¹⁹ Invasivorism can counteract this trend by introducing a variety of underutilised species into our diets, increasing the diversity of our food sources, and potentially reducing pressure on both agricultural and natural ecosystems.

Finally, incorporating invasive species into diets can help to educate us as consumers about the ecological impacts of our choices, encouraging discussions about responsible consumption, conservation, and sustainable resource management.²⁰ For instance, in the United States, the visually striking but ecologically damaging lionfish is now being served in various restaurants to control its population.²⁶ Similarly, in Europe, the idea of eating invasive species is gaining traction, with crayfish being served as the new "Berlin lobsters", celebrating the taste of these prolific breeders, currently undermining local waterways.²⁷

The prickly pear is considered invasive in Australia, Ethiopia, South Africa, and Hawaii, among other locations. As well as having an edible fruit, which is rich in vitamin C, the young cactus pads can be eaten as well, usually picked before the spines harden.

The risks of invasivorism

Despite the obvious positives, eating invasive species poses a few important ecological and ethical questions. One main concern is that may not effectively stop their spread, as sometimes simply removing these species fails to address the root causes that drive their proliferation.²⁰ A more strategic approach, targeting their survival needs rather than their numbers, could prove more effective. However, managing invasive populations is complex, with varied outcomes across ecosystems and species.²¹ Moreover, the commercialisation and transportation of these species for culinary purposes could facilitate their spread, exacerbating the very problem invasivorism seeks to address.²⁰ Furthermore, once invasive species gain economic value, complete eradication becomes difficult due to commercial interests. This is clearly demonstrated by invasive species already part of the food industry, such as the brown trout in New Zealand and the crayfish in North America.^22, 23 Ironically, in some cases, invasive species are so well received by the food industry that their maintenance over time becomes necessary to meet commercial demands, conflicting with ecological management goals.

This complex interplay of ecological and economic factors must be carefully considered when promoting invasivorism as a conservation strategy.

The way forward

Incorporating invasive species into our diets offers a creative solution to a pressing environmental challenge, a unique fusion of culinary innovation and ecological responsibility. However, this approach needs careful management to ensure that it contributes positively to environmental conservation without unintended ecological consequences.

Collaboration between chefs and ecologists is crucial for comprehensively understanding the species' ecology.²⁴ This knowledge is vital for making informed decisions about which species to target, how to harvest them sustainably, and how to prepare and serve them in ways that do not pose ecological risks. On the other hand, collaboration with the culinary industry can represent an asset for scientists and policymakers in public education and outreach. Chefs, with their public influence, can play a critical role in raising awareness about the impact of invasive species on ecosystems, educating the public about the importance of ecological balance and the role that conscious consumption can play in achieving it.