It is now widely recognized that biodiversity loss is one of humanity's most serious environmental problems. Our population continues to grow. As of 2022, it is at 7.95 billion. This would be a neutral fact were it not for our population increase putting pressure on available resources.
The ongoing Holocene extinction event we face is caused by anthropogenic factors and represents the sixth mass extinction to occur on Earth. Our impact on the ecosystem is complex, but it is currently driving many macro and microscopic species to extinction.
The Holocene extinction is a large-scale loss of biodiversity has been underway for centuries, but accelerated rapidly during the 20th century. It is frequently compared to other mass extinctions, such as the Cretaceous–Palaeocene extinction event that wiped out the dinosaurs. Unlike prior mass extinctions, the Holocene extinction is largely caused by human activity. The name originates from Greek and means "entirely recent".
Only a proper understanding of our actions can lead to responsible policymaking and to the implementation of measures against costly biodiversity loss. Actions that are causing this include:
- Clearing forests and grasslands to make way for agriculture
- Mining
- Urban development
- Sewage discharge
This habitat loss is one of the biggest threats to biodiversity, alongside pollution and irreversible climate change.
Human Impact on Biodiversity (Definition)
So to break down this title, biodiversity comes from biological diversity. It refers to all life on Earth or anything that has recently been alive. The human impact part refers to any anthropogenic factors. These are usually separated from the rest of the natural events when analysing data.
The United Nations Convention on Biological Diversity defines biodiversity as "the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems".
Biodiversity and the Human Impact on the Earth
Humans, when taken as a whole, are a biotic factor that has been influencing habitats and their biodiversity for thousands of years. Some of the biggest reasons for the human population growth and pressure put on biodiversity resources are:
- High intelligence, characterized by manual dexterity and adaptability, resulting in an ability to colonize and engineer numerous terrestrial habitats on Earth.
- Ability to travel intercontinentally and even outside Earth's boundaries and introduce exotic organisms into new environments.
- Rapid consumption of resources through industrialization, with high waste outputs and energy costs due to inefficient machinery.
- High space requirements for infrastructure.
- Relatively high territoriality and the elimination of other organisms, especially of large-sized predators.
- Selective pressures exercised on a few species considered useful or of high economic interest at the expense of genetic diversity.
Human impact on Loss of Biodiversity
Biodiversity is also made up of insects, fungi, bacteria, and other living beings. These have traditionally been hard to study and quantify due to their small size or "hard-to-access" living environments. Animals only represent a tiny portion of all biomass on Earth, and we believe that anthropogenic loss of biodiversity has been even more significant on plants and arthropods (insects - phylum Arthropoda).
Below, we will look at a few ways human are impacting biodiversity.
Direct exploitation
This is a type of exploitation in which humans normally come in direct physical contact with the biodiversity resources. This includes:
- Food: the nutritional or cultural values attributed to certain foods override the need for care needed due to the resource's scarcity. This includes the Bluefin Tuna Thunnus Thynnus and the Chinook Salmon Oncorhynchus tshawytscha. This means that they keep being caught and used in traditional cuisines around the world, despite becoming rarer.
- Fashion: in the USA, great egrets and roseate spoonbills had been overhunted in the 19th century for their bright feathers.
- Exotic pet trade: the African grey parrot Psittacus erithacus is endangered by the pet trade.
- Unsustainable traditional medicines: all parts of the tiger, including bones, internal organs, and whiskers, are believed to hold specific medicinal properties in Chinese medicine. The South China tiger is on the verge of extinction in the wild.
- Eradication of competition: the intentional elimination of a species for various reasons. 30 million American bison were culled in the 1800s due to the intraspecific competition for space and resources between human settlers and North American indigenous tribes. Pelicans may also be seen as pests by fishermen, although the pelicans' role in the ecosystem is extremely valuable.
Indirect Exploitation
Indirect exploitation is often unintentional, as it results from primary human activities that may not specifically target the elimination of biodiversity. This includes:
- Accidental introduction of alien species with negative consequences: earthworm Lumbricus terrestris introduced in North America; ash dieback fungus Hymenoscyphus fraxineus imported into the UK through the sapling trade.
- Bycatch: bycatch from industrial fishing alone can lead to species extinctions of sharks and dolphins, due to the rate at which they get caught in nets and asphyxiate.
- Changes in abiotic factors: heat island effect, soil compaction due to heavy weights, reduced humidity.
- Food chain impacts: primary extinctions can cause a number of other extinctions down the line, in a form known as the domino effect. The disappearance of the dodo bird from the island of Mauritius is leading to the extinction of the Calvaria major tree.
- Habitat loss: fragmentation brings the loss of genetic resources and leads to inbreeding (inbreeding depression) within existing populations limited by geographical conditions. Cheetahs are affected by this.
There is a marked human preference for coastal living. About 40% of the world's population lives within 100 kilometres of the coast.1 The epipelagic zone (ocean surface at around 200 m), where aquatic plants can use photosynthesis, is also home to the largest ocean biodiversity but is also the most exploited by humans. There is a marked competition for space and resources between humans and other biodiversity in the coastal zones.
Human Impact on Biodiversity Examples
Each species and habitat has a unique role to play in the functioning of the ecosystem. The loss of even one species can have a ripple effect on an entire community and their habitat.
Losing a keystone species such as the tiger shark Galeocerdo cuvier can cause seagrass ecosystems to collapse due to an explosion in their prey numbers (sea cows). Unfortunately, many species of shark, such as the tiger shark and their prey, sea cows, are either vulnerable or endangered due to fishing pressure and water pollution.
The Aral Sea - net biodiversity loss
68,000 square km of landlocked sea had completely dried up in 2014 for the first time in recorded human history, primarily due to a series of water extraction projects for irrigation of plants such as cotton, which unintentionally caused the ecosystem to collapse. Twenty-four species of endemic fish species went extinct in 60 years, and roughly 80% of native Aral Sea invertebrates might have died out.
Endemic species are those that are heavily adapted to one specific environment, and which do not occur anywhere else other than in the specified environment or location.
The Great Pacific Garbage Patch
This is a 1.6 million square kilometres collection of floating marine debris which resulted from human activities - a collection roughly four times the size of Britain. This debris, mostly made of plastics, accumulates in the digestive systems and tissues of animals that feed at sea (e.g. jellyfish) causing health complications and even death.
The Molai Forest - net biodiversity gained
The origins of the Molai Forest Reserve are attributed to one person's efforts. A forestry worker named Jadav Payeng, born from the Mishing indigenous tribe, had planted and taken care of a forest in Assam, India, over several decades. This forest area now measures 550 acres and comprises various tree species native to the Indian subcontinent, such as the arjun Terminalia arjuna. Animal species such as Asian elephants, Bengal tigers and Indian rhinoceroses use the forest for foraging, shelter and reproduction.
Positive Human Impacts on Biodiversity
Human conservation efforts can help reverse biodiversity damage or loss caused by natural events and disasters, thus rendering an ecosystem more resilient. In most cases, regulations are in place to prevent over-exploitation by humans or to alleviate habitat damage.
| Method | Example |
| Legislation & Protocols | The Wildlife and Countryside Act 1981, EU Birds Directive 2009, The Natural Environment and Rural Communities (NERC) Act 2006, The Convention on International Trade in Endangered Species (CITE) 1975, Organizations e.g. The Association for the Biological Diversity Conservation (ACDB). |
Conservation | Sites of special scientific interest (SSSI) e.g. Kinver Edge (UK), UNESCO World Natural Heritage Sites e.g. Danube Delta (Romania & Ukraine). |
Breeding programmes | Amur Leopard European Breeding Programme (e.g. Yorkshire Wildlife Park Project); Staghorn corals Acropora cervicornis bred off the coast of Honduras. |
| Relocation | 21 individual Guam railbirds Hypotaenidia owstoni were captured in 1981, bred, and then successfully reintroduced in the wild. Due to the Brown Tree Snakes Boiga irregularis introduction by the American military on the birds' native Pacific island, Guam, they were initially released on a different island. |
| Ecological restoration | Beaver reintroduction (UK), Camargue Natural Park lagoons and marshes restoration (France). |
| Seed banks | The Millennium Seedbank (UK), the Svalbard Global Seed Vault (Norway). |
| Abiotic control | Water, minerals, light, temperature, oxygen, etc. all can be introduced into a new habitat to enhance its characteristics or resilience. |
Minerals or raw materials that would otherwise remain locked deep in the lithosphere or elsewhere, can be extracted by humans and used to enrich the biosphere, to provide food and shelter that sustains biodiversity. Isn't that impressive?
Biodiversity Loss and its Impact on Humanity (Summary)
It is now widely recognized that biodiversity loss is one of humanity's most serious environmental problems. Biodiversity loss can be defined as a decrease in the number or variety of species in an ecosystem. This can happen through habitat loss or degradation, overexploitation of resources, pollution, invasive species or climate change. All of these threats are caused by human activity.
Effects of biodiversity loss include:
Loss of livelihoods and income
Health impacts
Local migration
Conflicts
Loss of food resources
Higher temperature variations, flood incidence, wind
For example, the loss of pollinators such as bees and butterflies has led to a decline in crop yields, with knock-on effects on food supplies.
"Domestic honeybees kept in hives pollinate approximately 34% of 100 economically important crop species"2, such as zucchini and strawberry, while the rest is done by wild species such as bumblebees. Honey bee pollination alone is estimated at $15 billion in the US.
Rainforests also provide ecosystem services such as:
Regulating atmospheric moisture levels and precipitation patterns
Other water cycle regulation
Flood prevention
Carbon storage
Timber
Food
Medicine (discovered, and potential)
And other natural resources that are vital to human society.
"Rain forests are the richest, most productive and most complex ecosystems on Earth, yet they cover less than 2% of the Earth's surface. They are currently being destroyed at the rate of one football field every six seconds. Rainforests also contain half of the existing animal and plant species in the world! If forest clearance continues at the current rate, scientists estimate that nearly all tropical forest ecosystems will be destroyed by 2030."3
Hopefully you now have a better understanding of the impact that we have on biodiversity and also the ways that you can help mitigate them.
Human Impact on Biodiversity - Key takeaways
- Human are a major biotic cause of biodiversity loss in the Holocene.
- The biomass distribution on Earth underlines the difficulties of studying anthropogenic effects on microscopic life forms.
- Direct and indirect exploitation and two ways through which humans interact with biodiversity.
- There is an undeniable positive potential for humans to preserve and protect the unique biological resources present on Earth, through initiatives such as seed banks, genetic research, etc.
- Humanity is heavily impacted by the loss of biodiversity, such as wild pollinators and rainforest ecosystems.
References
- UN, The Ocean Conference, 2017. Accessed 19.06.22
- Reviveabee, How much of our food supply do bees pollinate, 2021. Accessed 25.06.2022
- Marlowe Hood, Football pitch of rainforest destroyed every six seconds, 2020. Accessed 24.06.22
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