Invasive alien species are threatening indigenous plants and animals around the world. In what is being described as the second largest driver of recent extinction events, alien species are not only threatening specific groups such as plants and amphibians, but global biodiversity as a whole(1,2). And yet, there is an obvious way to limit alien species we are only just starting to explore.
Under The Sea
Overfishing is ravaging our oceans and fish stocks are rapidly declining. While there is growth in sustainable fishing, it’s still far from enough to feed an ever growing human population. Moreover, invasive species are decimating marine ecosystems. Notably, the Indo-Pacific lionfish (Fig.1) is devastating reef and nearshore ecosystems on the US south-eastern coast and throughout the Caribbean(3). Currently there is no strategy in place to remove or effectively control this pervasive pest(3). However, consuming alien species could be a step towards mitigating the damage caused by invasive alien species, while decreasing the effect of overfishing.
Aliens On Land
Effects of alien species are not limited to marine ecosystems either. Terrestrial alien species are believed to be an important factor in a host of recent extinctions. A study investigating the cause of extinction events used data from the International Union for Conservation of Nature Red List of threatened species(1). The team compiled a list of 247 animals and plants that are either believed to be extinct or extinct in the wild since 1500AD(1). They found that for amphibians, mammals, and reptiles, alien species were the greatest threat associated with extinction events(1). In contrast, plants fared better with agriculture being described as its main threat, and alien species ranked fourth(1).
Unlike lionfish, which is considered controversial due to venom the fish possesses, eating most terrestrial alien species should be considered less risky. Rabbits have plagued Australia since their intentional introduction by Thomas Austin in 1859. The current method of control is a virus that devastates populations, thus limit the damage these animals otherwise cause(4). While it’s understandable there was a need for swift and effective control on what is described as an explosive growth in rabbit numbers, there are better uses for an animal that’s widely consumed elsewhere. Animal products are sent around the world, with many techniques to preserve what is otherwise a perishable commodity – drying, salting, smoking, and curing to name a few. These preservation methods could allow these animal products to be used for international aid, foodbanks, and animal welfare, including zoos and animal sanctuaries.
The UN Food and Agriculture Organisation (FAO) is already emphasising how insects are a potential solution to combat future food insecurity(5). While some cultures consider certain insects as delicacies, others might be less comfortable consuming what are often seen as pests (Fig.2). Regardless, there is a large body of evidence showing how insects are a good alternative source of fat and protein(5). The FAO report highlight how the larvae of red palm weevil are consumed across Asia, Africa, and Latin America. An insect so delicious Linnaeus even added an anecdote detailing his delight in Systema Naturae. This is the same species that has invaded the Mediterranean wreaking havoc on date palm crops. Therefore, an environmentally conscious solution compared to the systematic use of pesticides, is to show those affected how to prepare the larvae and that eating insects shouldn’t be a taboo.
There are problems to overcome before any schemes to harvest alien species for consumption are launched. Eating alien species alone isn’t likely to make much impact on the devastation such species cause. Scientific oversight should govern the process to ensure the impact and methods of removing alien species is beneficial to the whole ecosystem. Removing invasive species could problematic if said species was successful at completely removing and replacing an indigenous species. It is possible that the alien species has become integral to its adopted ecosystem. If possible, a solution would be to harvest the invasive species whilst conducting reintroduction programmes of the original fauna. However, this is a relatively small problem when considering the implications of assigning economic importance to alien species.
A suspected driver of current intentional introductions of alien species is economic benefit through exploitation. The Nile perch is an excellent example of this process (Fig.3). This perch was introduced into Lake Victoria in 1954 to offset the overfishing of native fish stocks(2). Unexpectedly at the time, the Nile perch proliferated and is believed to be responsible for the extinction of more than 200 species endemic to that African Great Lake(2). Additionally, due to it’s oily flesh, more trees were felled for fires when the perch was dried(2). The intentional introduction of the Nile perch to Lake Victoria has not only devastated the lake’s biodiversity, but also has lasting effects on the communities the lake supports. This scenario highlights a serious consequence of increasing the value of alien species if not managed correctly.
Invasive alien species are wreaking havoc around the world. Current methods of control, if any, are often ineffective or environmentally costly. Furthermore, we are part of a growing population with rising food insecurity. While eating alien species may not completely control the detrimental effects they have, it’s a step in the right direction to solve the aforementioned problems. Both of them. However, there are some risks that have come up in the past, but with proper oversight they should be manageable. We should be doing everything in our power to stop the spread of alien species, and eating them might just benefit us while we do it.
- C. Bellard, P. Cassey, T. M. Blackburn, Alien species as a driver of recent extinctions. Biol. Lett. 12, 20150623 (2016).
- S. Lowe, M. Browne, S. Boudjelas, M. De Poorter, 100 of the World’s Worst Invasive Alien Species: A Selection From The Global Database. Invasive Species Spec. Gr. 12, 12 (2004).
- M. Hixon, S. Green, M. Albins, J. Akins, J. Morris, Lionfish: a major marine invasion. Mar. Ecol. Prog. Ser. 558, 161–165 (2016).
- T. Strive, J. D. Wright, A. J. Robinson, Identification and partial characterisation of a new lagovirus in Australian wild rabbits. Virology. 384, 97–105 (2009).
- A. van Huis et al., Edible insects. Future prospects for food and feed security (2013), vol. 171.