Not all species that are not native to a specific location are invasive. To be considered as such, they must adapt to new areas easily and reproduce quickly. By outcompeting the native species, invasive species thrive and cause harm to the habitat and the economy. Humans have undoubtedly had a significant impact on the environment leading to catastrophic climate crises, and threatening the planet and its inhabitants. However, can we really say that humans are an invasive species?

The National Geographic Society defines an invasive species as an “organism that is not indigenous, or native, to a particular area and can cause great economic and environmental harm to the new area”. Similarly, the US National Invasive Species Information Centre defines invasive species as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.” 

According to both the definitions outlined above, to be categorised as an invasive species, certain criteria must be fulfilled. These include being non-native to the locality, adapting and reproducing quickly, and causing environmental and economic harm to the area.

While the climate changes naturally, humans are now considered the main drivers of climate change. By attempting to modify the natural environment to conform to the needs of modern societies, humans have caused catastrophic events such as global warming, environmental degradation, mass extinction, and biodiversity loss that have led to an ecological crisis and ecological collapse. Humans have affected and changed biodiversity and the ecosystem in multiple ways. Approximately one million flora and fauna species are threatened with extinction, more than ever before in human history, as a direct result of human activity. A report by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) found that three-quarters of land and 66% of the marine environment is significantly modified by human actions. 

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One of the most famous examples of a species that became extinct because of human actions is the dodo bird, a bird once native to the island of Mauritius. Discovered by Portuguese sailors in the 1500s, the specie was erased from existence less than 200 years later. Due to their flightless nature, the fact that they likely nested on the ground, possibly only laid a single egg every year, and had no natural predators making them unafraid of humans, they were an easy source of meat. As more and more humans settled on the island, the consequential loss of habitat further threatened the existence of the bird. The settling of humans also brought other animals to the island and the unsustainable harvesting of the dodo, combined with habitat loss and a losing competition with new species settling into the island eventually led to the complete eradication of the bird.

The Socio-Economic Impact of Biodiversity Loss

Loss of biodiversity is not only an environmental issue but also a socio-economic one. Research has found that biodiversity in the form of ecosystem services such as food provisioning, carbon storage, and water and air filtration has a high economic value – worth more than US$150 trillion annually. Loss of biodiversity comes as a significant threat to many businesses as they face higher raw material costs, as sources of food, fuel, structural materials, and medicinal resources are greatly reduced. Irreversible species loss and changes to biodiversity and ecosystem processes are likely to cause a non-linear increase in cost to society in the long run, especially once the threshold of the resilience of the ecosystem is crossed. Not only will there be economic losses to society but also social ones, as biodiversity greatly influences cultural, spiritual, and social values. 

Biodiversity Loss and Food Insecurity

Biodiversity forms the foundation of society’s food system. Not only is it directly the food we eat – such as domesticated and wild livestock and crops, and aquatic species – but it is also the variety of plans and organisms that are essential to production processes that maintain healthy soils, regulate water, and pollinate plants. 

The economic value of this contribution is considerable. Pollinating species, like bees, birds, bats, and many more, contribute directly to between 5%-8% of current global crop production, the annual value of which was US$235-577 billion in 2015. A higher density of pollinating species leads to higher crop yields and so their dramatic decline poses a substantial threat to the economy. As found by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the loss of animal pollinators would result in a net welfare loss of approximately US$160-191 billion to crop consumers across the globe and a further loss of US$207-497 billion to producers and consumers in other markets. 

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Food production has increased significantly over the years to keep up with growing demand. A key indirect driver of this loss of biodiversity and harm to the ecosystem is increased population. Since the 1970s, during which the global human population has more than doubled from 3.7 to 7.6 billion. One of the greatest risks a growing population poses is a rapid increase in per capita consumption. As the population has grown, habitat destruction such as deforestation has also had to increase to make space for agricultural land. Furthermore, urban sprawl and transportation infrastructure increase pollution and global temperatures, critically changing major habitats. 

Trends in agricultural production, fish harvest, bioenergy production, and harvest of materials have increased in response to population growth, rising demand, and technological development, which has come at a steep price. Between 1962 and 2017, it is estimated that approximately 340 million hectares of new croplands were created globally and 470 million hectares of natural ecosystems – around half the area of China – were converted into pastures. The International Union for Conservation of Nature has predicted that the number of endangered species rises in areas with high human population growth. 

Are Humans an Invasive Species? 

Humans have been the cause of a lot of ecological and economic harm worldwide. The species’ unprecedented population growth has resulted in numerous instances of modified habitats, which have led to significant losses of biodiversity. However, to be categorised as an invasive species, humans must also be non-native. Most anthropologists agree that Homo Sapiens originated from East Africa and managed to spread out to every continent on Earth. As humans continued to migrate and colonise previously inhabited parts of the earth, large-mammal extinctions ensued.  By crossing the land bridge into North America approximately 15,000 years ago, humans contributed to the disappearance of large animals such as mammoth and mastodons mainly due to a rapid increase in hunting activities.

As explored above, we can conclude that humans are an invasive species. As humans spread out to parts previously uninhabited by them, the increase in population caused losses in biodiversity even hundreds and thousands of years ago. This has continued to the present day and the ever-growing human population is still significantly altering the ecosystem and resulting in serious economic and ecological costs to this day.

How Can Humans Minimise Their Impact?

However, there are still ways in which these impacts can be minimised. To live more in harmony with the habitat, there must be sustainable human development, focusing not only on societies needs but also on taking into consideration the threshold of the planet’s ecosystems. Exploiting non-renewable resources alters the habitat in an unsustainable way and unrestricted human activity threatens not only the surrounding biodiversity due to climate change but also human life itself. 

The best way to develop a more sustainable relationship with the planet and the ecosystem is to phase out fossil fuels and further the development and utilisation of clean, renewable energy. Moreover, promoting education, alongside science and technology, is increasingly important to help understand efficient utilisation of natural resources and promote human awareness and participation in environmental education and living. Lastly, shifting to sustainable agricultural practices and promoting nature-based solutions for urban areas are extremely important steps to tackle the increasing human population and the consequential increase in consumption globally. 

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