Endangered Species 101: Causes, Impact, and Protection Guide

Today, at least a third of plants and animals in the US would be as dead as a dodo were it not for the intervention provided by the Endangered Species Act (ESA).

ESA provides the necessary legal framework to enforce the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulations, whose enactment on March 3, 1973, came against the backdrop of painful extinctions, including the Passenger Pigeon (1914), the Carolina Parakeet (1918), and the Heath Hen (1932).

Despite these strict regulations, the world has continued to experience an accelerating extinction rate of notable species like the Western Black Rhinoceros, the Pinta Island Tortoise, and the most recent precious honeycreeper birds, just to mention a few. This decline of global species populations has been at a record high of about 70% for the last 50 years.

Scientists warn that the continued loss of species could lead to an extinction domino effect. An extinction of one species can disrupt the food webs, compromise ecosystem services like pollination, reduce genetic diversity, degrade habitats, and exacerbate climate change.

But how did we get here? What is the current situation, and what can you do about it?

How Do Species Become Endangered?

The most significant direct threat to wildlife is habitat loss, which can occur for several reasons, such as melting glaciers, volcanic eruptions, and human activities like trafficking. The latter is the second most significant threat to wildlife and one of several elements of human impact on species’ endangerment.

While eruptions and inbreeding may be unrelated to human activities, human impact can explain over 96% of all mammal species extinctions of the last hundred thousand years.

Unfortunately, with globalization, industrialization, and conflicts, man’s interests are increasingly clashing with nature’s interests, leading to the following situations;

1. Habitat Loss

Habitat loss is identified as a primary threat to 85% of all endangered species, and it may be outside human intervention. For example, volcanic eruptions on the Galápagos Islands have historically endangered the Galápagos Tortoise (Chelonoidis nigra), destroying food sources and habitats. The 2015 eruption had lava flow covering swaths of land, destroying habitats, disrupting nesting sites, and altering the ecosystem.

However, human activity is increasingly becoming the main cause of habitat loss. Agriculture and industrialization’s need for vast land and space has led to bush clearing, leaving the habitats inhospitable to the species.

For example, the Amazon Rainforest, often referred to as the “lungs of the Earth,” has now lost over 20% of its cover since 1970, totaling about 820,000 square kilometers of forest. The agricultural expansion, logging, and infrastructure development leading up to this deforestation have drastically affected species like the Brazil Nut Tree (Bertholletia excelsa), the Amazon River Dolphin (Inia geoffrensis), and the Poison Dart Frogs (Dendrobatidae family).

Habitat loss has also proven to cause an extinction domino effect, given the complex interdependencies within ecosystems. The destruction of vegetation could displace critical prey or destroy crucial breeding grounds, drastically disrupting the ecosystem.

For example, the old-growth forests of the Pacific Northwest in the United States suffered logging activities in the late 20^th century, leading to a drastic decline in the Northern Flying Squirrel, which depended on the forest for food and habitat. The Squirrel was also a critical food source for the Northern Spotted Owl, whose population declined as the squirrels’ by 1990. The two species were listed under ESA in 1990 and, despite recording some stabilization, remain threatened.

2. Inbreeding

Due to inbreeding, the Przewalski’s Horse (Equus ferus przewalskii) has become extinct in the wild. Cheetahs are also threatened by inbreeding, while species like the Axolotl (Ambystoma mexicanum), the Kakapo (Strigops habroptilus), the Iberian Lynx (Lynx pardinus), and the Florida Panther (Puma concolor coryi) remain critically endangered.

Plant species are not spared, with the isolated Mountain Pine Beetle (Pinus contorta subsp. murrayana) and the Australian Slender Rushpea (Sarcostemma viminale) listed as endangered mainly due to self-fertilization.

When these closely related species reproduce, subsequent generations may record declined genetic variation and become susceptible to harmful genetic traits. The importance of genetic diversity, even for humans, cannot be overstated. However, species like the critically endangered Alabama Beach Mouse record small population sizes and live in fragmented and isolated habitats, making inbreeding inevitable.

That is not to mention the impact of human activities on this malpractice. Throughout the 19^th century, the overhunting of once one of the most abundant bird species in North America, the Passenger Pigeon (Ectopistes migratorius), reduced their numbers and triggered massive inbreeding and subsequent extinction.

Today, the North Atlantic Right Whale (Eubalaena glacialis) species remains endangered after it was overhunted in the 20^th century for the oil, blubber, and baleen plates. The small population limits genetic diversity, leading to increased disease susceptibility, low calving rates, and reproductive failures.

3. Climate Change

Climate change has also had a significant blow on biodiversity. Increases in sea levels, temperatures, and humidity have caused extinctions of species such as Bramble Cay Melomys (Melomys rubicola) and Golden Toad (Incilius periglenes). Many more, including the Staghorn Coral (Acropora cervicornis) and the Quiver Tree (Aloe dichotoma), remain critically endangered and threatened.

Global warming is projected to commit over one-third of the Earth’s animal and plant species to extinction by 2050 if current greenhouse gas emissions trajectories continue. With warm temperatures, habitats like the tundra biome have their permafrost thawing at alarming rates, leaving native species without food and habitats.

The erratic weather patterns have also left migratory animals confused as their seasonal cues are disrupted. The full wrath is perhaps felt in the oceans, where rising levels damage ecosystems and threaten critical species like phytoplankton.

It’s the exact result of activities like lighting up landfills and relying on nuclear power, which release gas emissions and rip the ozone layer. This impacts species in the ecosystem differently and is likely to trigger a domino effect on plants, animals, and humans. Ironically, it is the same humans who catalyze the process.

4. Other Human Activities

Human activities started to dominate as the cause of species extinction during the Industrial Revolution (18^th -19^th centuries). With heightened exploitation of natural resources, pollution, and habitat destruction, humans presented yet another threat to biodiversity.

Developed infrastructure, urbanization, and population influx have enhanced trade and travel, increasing the chances of spreading diseases to other species. This is in addition to the greater risk of encroachment, road accidents, and hunting.

Wildlife trafficking and removal from habitats is the second-biggest threat to species, pushing out native species and altering food chains. According to the International Union for Conservation of Nature (IUCN), over 1,000 species face extinction due to illegal trade, smuggling, and poaching.

A common victim is the African elephant species, whose population has plummeted by over 50% since 1980 due to heavy trafficking for their ivory tusks. The Pangolins from the Manidae family, which live in Africa and Asia, have also suffered overexploitation in the last decade for their scales and meat. The population has declined by over 80% since the year 2000, and most of these have been listed as “critically endangered.”

Humans’ release of toxins and pollutants to the environment also endangers species. The use of insecticides may affect pollinators, and poison marine life when washed into waterways. Similarly, failure to recycle trash and plastic impacts the ecosystem, especially the oceans, where over 100 million animals die annually.

The US Environmental Protection Agency (EPA) banned DDT (dichloro-diphenyl-trichloroethane) and PCBs (polychlorinated biphenyls) in 1972 and 1979, respectively, as they were proven to poison fish and the predator bald eagles. Since the ban, fish and bald eagle populations have bounced back tremendously.

What is the Endangered Species Act?

The US Congress passed the Endangered Species Act (ESA) in 1973 to promote the conservation of endangered and threatened species and their habitats. The Act mandates the US Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), and the National Oceanic and Atmospheric Administration (NOAA) to list threatened and endangered species, designate critical habitats, protect them, and develop recovery plans. ESA is a more eco-system-based policy than the species-centric illegal trade ban in the Lacey Act of 1900.

According to ESA, endangered species are those facing extinction based on the following factors:

• Population Size
• Geographic Range
• Overexploitation
• Disease
• Inadequate Regulation
• Genetic Diversity
• Habitat Loss
• Threats
• Trends
• Resilience
• Reproductive Strategies and Patterns
• Ecological Role

ESA also has a Threatened List for all species that tick most of these boxes but fail to make it to the Endangered Species List. They, too, enjoy protection from the relevant agencies to avoid any imbalance in the ecosystem.

How Do Species Get ‘Listed’ Under the Act?

Researchers from NOAA, USFSW, NMFS, or other organizations conduct regular reviews to determine whether a species deserves ESA protection. The FSW has laid out clear guidelines and requirements for anyone to file a written petition requesting a species addition to the list, an update on the status of an already listed species, or a revision of an existing critical habitat designation. It also publishes all the ESA petitions received.

On approval, the species qualifies for protection from the federal government. Henceforth, it becomes illegal to interfere with the species’ behavioral and breeding activities in their habitat. ESA also prohibits collecting, capturing, trapping, shooting, pursuing, harassing, or attempting any of these.

ESA’s major strengths lie in its vesting of powers to the public, the requirement to designate critical habitat to listed species, and warning to federal agencies against jeopardizing protected species. Relevant agencies are also required to conduct reviews at least every five years to record changes in the species or habitat and the progress of recovery plans. Today, the ESA lists over 2,150 species as either endangered or threatened.

Note that various states have their own versions of ESA, mainly focusing on species unique to them or not listed. Some examples of these laws include the Massachusetts Endangered Species Act (MESA, 1990) and the California Endangered Species Act (CESA, 1970).

IUCN Red List

Similarly, the International Union for Conservation of Nature (IUCN) lists all threatened and endangered species from more than 160 countries and has a network of over 16,000 voluntary scientists and experts worldwide. It is the largest and oldest global environmental network, founded in 1948, and endorsed by various international organizations, such as the United Nations Environment Programme (UNEP), Convention on Biological Diversity (CBD), and World Wildlife Fund (WWF).

The ESA, the EU’s birds and habitats directives, and CITES rely on IUCN assessments and Red List categories to guide the implementation and evaluation of relevant policies. To date, IUCN has assessed over 165,000 species and identified over 45,000 as facing extinction.

Below is a graphic presentation of the level of threat against different species.

IUCN categorizes its species list based on five threat levels: least concern, near threatened, vulnerable, endangered, and critically endangered. The last three categories form the list of species threatened with extinction normally called the Red List.

The table below details five factors that help determine IUCN’s Red List.

Criteria	Population Reduction	Geographic Range	Population Size (mature individuals)	Population Restrictions (mature individuals)	Probability of Extinction
Vulnerable	30-50%	Less than 2,000 sq. km for occupancy or less than 20,000 sq. km overall.	Less than 10,000.	Less than 1,000 or an occupancy below 20 sq. km.	10% for the next century.
Endangered	50-70%	Less than 500 sq. km for occupancy or less than 5,000 sq. km overall.	Less than 2,500.	Less than 150.	20% for the next five generations or a timeline of 20 years.
Critically Endangered	80-90%	Less than 10 sq. km for occupancy or less than 100 sq. km overall.	Less than 250.	Restricted to less than 50	50% within the next three generations.

READ MORE:
The Most Endangered Species in the World

Why Should We Protect Endangered Species?

Every life matters, and the loss of one can disrupt food chains and spell doom for other species, including humans. Besides, you have an ethical responsibility to protect diversity for future generations.

Statistics don’t look good either.

In 2023, US scientists declared 21 species officially extinct, including mammals, birds, mussels, and fish. Destroyed habitats were identified as a key factor.

Currently, the IUCN lists about 200 species of bees in the Red List, with declines recorded across the globe. This means reproduction in plants that rely on bee pollination may decrease, and food and habitats for other species may be affected. Similarly, coral reef cover supports over a quarter of marine species, but it’s now over 50% less for the last three decades. The looming impact is erosion, storms, and a massive loss of fisheries that we dearly rely on.

Therefore, protecting endangered species is more about us than it is about them. Read on to find out how;

1. Maintaining Ecosystems

Services like nutrient cycling, water purification, and flood regulation by native species drive a balanced ecosystem. For example, the African Elephant (Loxodonta africana) is pivotal in nutrient cycling as a megaherbivore whose dung is also a crucial food source. Unfortunately, their population continues to dwindle despite habitat protection and anti-poaching measures.  

Another worrying statistic regards the kelp species known to absorb climate-warming carbon dioxide and save the ecosystem. Today, these species are threatened by climate change, poor water quality, and overfishing. In the 19^th century, the unrestricted hunting of California sea otter, an apex species in the food chain, contributed to an increase in its prey, the purple sea urchins, which happen to prey on kelp. The result was drastic kelp decline due to the overwhelming predators and subsequent diminishing coast protection from storm surges and CO₂ absorption.

2. Opportunity for Innovation

In addition to offering ecosystem services like pollination, plants and animals are the primary sources of crucial materials used in medical innovation. For example, the Pacific yew tree (Taxus brevifolia) was almost becoming extinct when it was discovered to contain anti-cancer agents. Different species have also helped create antibiotics like Penicillin, blood thinners, painkillers, and more.

Most endangered species may not seem relevant today, but they could hold the answer to questions for future generations. For example, the bacterium (Thermus aquaticus) found in hot springs was historically regarded as unwanted until it proved to possess the Taq polymerase enzyme, which is crucial in DNA research.

3. Source of Income

Endangered species offer ecosystem services with direct or indirect economic benefits. The availability of pure water would reduce water treatment costs, carbon sinks would mitigate the economic costs of extreme weather, and soil fertility services would reduce the costs of fertilizers and improve agricultural productivity.

Local communities also benefit from the protection of endangered species. Relevant industries require human labor to harvest products like medicinal plants and fruits without depleting natural resources. For example, in Brazil, the nut industry employs thousands of families to harvest, transport, and process nuts from the Amazon.

Protecting endangered species also boosts ecotourism, another significant source of income worldwide. When tourists flock to habitats to observe these species, the country and local communities reap most of the benefits through the millions of jobs and billions of dollars ecotourism creates.

This development also encourages businesses and community-based conservation initiatives. Local communities receive alternative income through conservation efforts like monitoring wildlife and regular patrols. They also benefit from opportunities like hospitality, tour guiding, and transportation services.

For example, the sea turtles and the resplendent quetzal species are some key tourist attractions in Costa Rica, helping the country generate significant revenue and experience a business boom.

How to Protect Endangered Species

The governments and relevant organizations must spearhead the protection of endangered species to assess, protect, and restore them and their habitats. Similarly, you also have a personal responsibility to ensure that your actions do not contribute towards species vulnerability and extinction.

Fair enough, the federal government has made notable strides regarding funding and regulation to turn the tide on species endangerment and extinction. Landmark programs such as the ESA, 2023 America the Beautiful Initiative, the Land and Water Conservation Fund (LWCF), and more are providing the needed spirit to protect endangered species and habitats.

Government agencies also collaborate with independent organizations to assess, protect, and restore species. For example, the USFWS works closely with the North American Pollinator Protection Campaign to enhance and conserve pollinators. This nonprofit is one of the strongest advocates for resident and migratory pollinating populations.

Similarly, the Center for Biological Diversity works to secure a future for all species on the brink of extinction through science, law, and creative media, with a focus on protecting the lands, waters, and climate that species need to survive. Scientists from the center continuously study the species to check and determine whether it needs to be “threatened” or the more protective “endangered” status. If so, they compile the data in a petition asking relevant agencies to move forward on protection.

Below are five steps you can take today to help protect endangered species:

1. Learn and share– Learn more about endangered species and raise awareness whenever you get an opportunity.
2. Practice proper waste management—Dispose of your trash appropriately and have the right recycling garbage can to prevent animals from mistaking trash for food in the compound. Similarly, reduce the use of single-use plastics.
3. Observe friendly gardening– Plant friendly crops that support other species, especially pollinators. Avoid pesticides or invasive plant species.
4. Be on the lookout—Whether you’re riding a boat, fishing, or driving to work, watch for animals along the way and allow them to cross. Also, raise an alarm if you notice animals in distress.
5. Support initiatives– Volunteer and donate to organizations working towards the protection of endangered species and critical habitats.

The Bottom Line

The future is not entirely gloomy, but scientists warn that we should act now, given the intersectional issues surrounding species threats and extinctions. Besides addressing the extinction risks contributed by humans, we must consider indirect threats like pollution, agricultural practices, and climate change.

Most importantly, the relevant authorities must support us on this. Legislation is a major boost in tackling extinction, with ESA providing a successful example. Other influential pieces of legislation include the Marine Mammal Protection Act of 1972 and the Bald and Golden Eagle Protection Act of 1940.

Continued enactment and enforcement of protective legislation will drastically reduce the major causes of species endangerment and extinction. With proper environmental care, there won’t be much habitat loss, which is currently the biggest direct threat propagated by human activities. Trafficking and removal from habitat also require special attention, given that it’s the second biggest direct threat.

Notably, agencies like USFWS, NOAA, NMFS and organizations like the Center for Biological Diversity have taken sole responsibility for uncovering the fate of threatened species and providing the necessary protection and care. You, too, have a role to play, from supporting these organizations to living an eco-friendly lifestyle that promotes biodiversity.