Top 10 ways to save wildlife
This Sumatran tiger is among the many wildlife species under threat of extinction.
There are more than 7 billion people on Earth. Imagine if every one of us committed to do one thing — no matter how small — to protect wildlife every day. Even minor actions can have a major impact when we all work together. Here are ways you can make a difference:
1. Adopt. From wild animals to wild places, there’s an option for everyone. Get together with classmates to adopt an animal from a wildlife conservation organization such as the World Wildlife Fund (WWF). Symbolic adoptions help fund organizations.
2. Volunteer. If you don’t have money to give, donate your time. Many organizations and zoos have volunteer programs. You can help clean beaches, rescue wild animals or teach visitors.
3. Visit. Zoos, aquariums, national parks and wildlife refuges are all home to wild animals. Learn more about our planet’s species from experts. See Earth’s most amazing creatures up close.(© Carlos Caetano/Shutterstock)
4. Donate. When you visit your local accredited zoos and nature reserves, pay the recommended entry fee. Your donations help maintain these vital conservation areas.
5. Speak Up. Share your passion for wildlife conservation with your family. Tell your friends how they can help. Ask everyone you know to pledge to do what they can to stop wildlife trafficking.
6. Buy Responsibly. By not purchasing products made from endangered animals or their parts, you can stop wildlife trafficking from being a profitable enterprise.
7. Pitch In. Trash isn’t just ugly, it’s harmful. Birds and other animals can trap their heads in plastic rings. Fish can get stuck in nets. Plus, trash pollutes everyone’s natural resources. Do your part by putting trash in its place.A western lowland gorilla holds her baby. You can help protect their natural habitat by recycling your cellphone. (© Eric Gevaert/Shutterstock)
8. Recycle. Find new ways to use things you already own. If you can’t reuse, recycle. The Minnesota Zoo encourages patrons to recycle mobile phones to reduce demand for the mineral coltan, which is mined from lowland gorillas’ habitats.
9. Restore. Habitat destruction is the main threat to 85 percent of all threatened and endangered species, according to the International Union for Conservation of Nature. You can help reduce this threat by planting native trees, restoring wetlands or cleaning up beaches in your area.
10. Join. Whether you’re into protecting natural habitats or preventing wildlife trafficking, find the organization that speaks to your passion and get involved. Become a member. Stay informed. Actively support the organization of your choice.
What You Can Do for Wildlife
STAND UP FOR WILDLIFE
-Your voice matters! Write to your federal and state elected officials encouraging them to support policies that protect wildlife.
–Sign up for action alerts from AWI, which keep you informed about urgent animal protection issues and provide quick and easy ways to get in touch with policymakers.
-Check out AWI’s publications about various wildlife protection issues, and share the publications with others.
-Visit AWI’s Action Center to take action on current action alerts.
MAKE YOUR YARD WILDLIFE FRIENDLY
-Plant native species of flowers, trees, and bushes in your yard. This gives wild animals food, shelter, and a place to raise families. Learn more about creating wildlife habitat in your yard.
+To attract birds to your yard, learn which native plant species are best for your location.
+To attract butterflies and moths to your yard, learn which native plant species are best for your location.
+To help imperiled monarch butterflies survive, plant native milkweed. Learn which species of milkweed are native to your region, and find milkweed suppliers in your area.
-Reduce the amount of lawn in your yard. Lawns offer minimal food and shelter for wildlife. -Try replacing part of your lawn with garden beds or native plants and flowers instead.
-Get crafty! Buy or build your own birdhouse or bat house. This can provide hours of fun for the whole family.
-No yard? No problem! Balconies and patios are great locations for container gardens.
-Do not use pesticides, insecticides, herbicides, or chemical fertilizers on your lawn or garden beds. These products are the leading cause of wildlife poisonings, and are also toxic to companion animals.
-Reduce light pollution: artificial light at night has severe negative effects on wildlife. To help, only use lighting when and where it is needed, properly shield all outdoor lights, keep your blinds drawn during the evening, and if safety is a concern, install motion detector lights and timers.
-Rethink fall cleanup: leaves, dead flower heads, and ornamental grasses provide critical food and shelter for birds, butterflies, bees, and other beneficial insects during the winter months. Learn more about how fall yard cleanup harms wildlife.
PROTECT THE ENVIRONMENT
-One of the easiest and most effective ways to help wildlife is to preserve the environment in which the animals live.
-Volunteer with organizations in your area to restore native forests, grasslands, and coastal ecosystems by planting native species, manually removing invasive plant species, and taking out old fences.
-Participate in or hold your own local trash clean-up to help protect the habitats of imperiled species and other wildlife.
-Reduce, reuse, recycle!
+Reduce: Manufacturing consumer products uses energy and natural resources, and creates waste and pollution. When we consume less, we need fewer natural resources and produce less waste. Some waste, like plastic bags and bottles, can make its way into wildlands and oceans, with negative consequences for endangered species and other animals. Reduce or eliminate your use of single-use plastics, which are difficult to recycle and persist in the environment for decades.
+Reuse: Do not throw it away if it still has a use! If you have unwanted books, toys, clothes or other items in good condition, consider giving them to charity instead of throwing them in the trash.
+Recycle: Avoid disposable products and products with excessive packaging or packaging that cannot easily be recycled. Find out what is recyclable in your area and recycle everyday items such as aluminum cans, glass and plastic containers, and cardboard and paper products. Dispose of electronics, batteries, and other potentially hazardous materials at municipal collection centers that will handle them properly.
-Save energy. Driving less, using energy efficient vehicles and appliances, and simply turning off the lights when you leave a room reduce energy use. Many power plants rely on coal and other fossil fuels that damage wildlife habitat when they are extracted, and pollute the environment and contribute to climate change when burned. Unplug appliances and chargers when not in use to eliminate electricity bleeding. You can also consider joining a community solar program or adding solar technology to your home or business.
-Respect wild animals by keeping a safe distance away, not approaching them, and not removing them from their environment. If you find young animals, particularly in the spring, do not handle them. Mothers often leave young for extended periods to forage. Although the young may appear to be abandoned, the mother will almost certainly return within 24 hours, and handling the young puts them in danger. If you encounter an injured wild animal, contact a certified animal rescuer in your area.
BE AN EDUCATED CONSUMER
-Think before you buy: Choose products that are energy efficient, durable, made from sustainable sources, and sustainably packaged. Avoid products that harm animals and habitats, such as gas-guzzling vehicles, disposable plastics and plastic microbeads, paper products not made from recycled paper, products grown with pesticides, and products made with palm oil. Also avoid products that test on animals and contain animal parts or derivatives.
-Never buy exotic animals, particularly those who were wild-caught, and never purchase parts and products made from wildlife, including souvenirs.
-Do not buy clothing or other products that use fur or feathers.
-Support genuine efforts that keep wildlife in the wild, such as ecotourism, photo safaris, or community-based humane education programs.
-Eat less meat, particularly beef. Cattle ranching destroys native vegetation, requires enormous amounts of water, damages soil, often results in lethal control of native predators, contaminates waterways, and produces methane, a potent greenhouse gas. Globally, conversion of forest to rangeland for cattle is one of the leading causes of biodiversity loss.
-Learn more about where your food comes from and what food label claims such as “sustainable,” “humane,” or “all-natural” really mean. If the product is rated or certified by an independent evaluator, find out what the rating/certification means and what animal and environmental advocates are saying about the certifier’s standards.
LEARN ABOUT IMPERILED SPECIES AND THEIR HABITATS
–Learn about the threats faced by threatened and endangered species. Teach your friends and family about endangered species and other animals that live near you.
-For information on species imperiled by trade, visit the Convention on International Trade in Endangered Species of Flora and Fauna (CITES) database at www.cites.org, the US Fish and Wildlife Service Endangered Species website, or the more inclusive International Union for Conservation of Nature (IUCN) Red List at www.iucnredlist.org.
-Visit a national wildlife refuge, park, or other open space and learn about the threatened and endangered species and other animals who live there. Stay informed and support policies that keep these areas wild and protect native species.
–Teachers: Help spread awareness in your own classroom about endangered species with our educational poster.
PROTECT ENDANGERED SPECIES
-The Endangered Species Act is an effective safety net for imperiled species—extinction has been prevented for more than 98 percent of the animals under its care. Urge your elected officials to preserve the important safeguards in the Act.
HELP PUT AN END TO INHUMANE TRAPS AND SNARES
-Support proposed federal, state, or local legislation against the use of indiscriminate and inhumane traps and snares for commercial purposes or to “manage” wildlife. Let your legislators, as well as your state wildlife agency, know that you support a prohibition on the use of cruel traps and snares in your state and across the country.
-If you see a non-target species (such as a dog, cat, bird, or threatened/endangered species) caught in a trap, seek veterinary care for the animal immediately. Next, document and report your findings to your local humane society and AWI. Such information will aid our efforts to pass laws that ban inhumane traps and snares.
-If you or someone you know hires a nuisance wildlife control business to address a wildlife conflict situation, do not allow them to use cruel traps or snares. Ask for their trapping policies in writing before you hire them.
HELP PROTECT BIRDS
-Up to 1 billion birds in the United States die each year due to collisions with buildings. Learn how to reduce bird strikes by making windows more bird-friendly.
-Keep your cat indoors. Cats are one of the top causes of bird deaths in the United States. A study by scientists at the Smithsonian Conservation Biology Institute reported that between 1.4 billion and 3.7 billion birds are killed each year by cats roaming outdoors. Therefore, one of the most important things pet owners can do to reduce direct wildlife mortality is to keep their cat inside.
HELP PROTECT WILD HORSES
-Learn more about wild horse issues.
-Contact your US senators and representative and urge them to help reform the Bureau of Land Management (BLM) wild horse program.
-Write to Secretary of Interior Deb Haaland and tell her you oppose the BLM’s overzealous wild horse roundup policy. The BLM admits it plans to round up far more horses than are adoptable—leaving many wild horses to remain indefinitely in long-term holding facilities. Urge the agency to act responsibly and stop removing these national treasures from the wild.
Saving the Animals Is More Important Than We Think
Animal conservation is a complicated issue, but it’s a core part of addressing the climate crisis.
When it comes to climate change, we’re inching dangerously close to the point of no return. This is what the world’s climate scientists have been saying for more than a few years. But since the problem is so vast, it’s easy to blow it off, burying your head in the sand and hoping it goes away on its own. So we wanted to offer some helpful tips on what you can do in your daily lives to put a dent in the climate change crisis. We hope to shed some light on the urgency of the problem through thoughtful deep dives that explore the systems and industry practices that exacerbate the problem and explore their social and ecological impacts. Within the series, you might also find some inspiring ways you can start to help make Earth more green and, hopefully, begin to turn back the clock on climate change.
Widespread animal extinction is one of the most dire consequences of the climate crisis, threatening the health of the planet and its ability to sustain all life, including those of humans.
Due to the instability of the climate crisis, one-third of all animal and plant species on the planet could face extinction by 2070, a February 2020 study warns. And a 2019 United Nations report said over one million species of plants and animals are at risk of being obliterated if we don’t make drastic changes.
This rate of extinction is due to the Anthropocene — the current geological age in which human activity is jeopardizing the Earth’s ability to sustain human life — which many climate scientists credit to the Industrial Revolution of the late 18th and early 19th century.
Zoologist and environmental studies scholar Malory Owen, a Masters of Science candidate at York University in Toronto, Canada, said, “Extinction is a natural process. It’s part of evolution, and it’s how we get change in our ecosystems over time. But the problem is since the Industrial Revolution, we have seen an incredible spike in that rate…through the Anthropocene.”
In 2019 alone, about two dozen species were declared extinct or nearly extinct, the Center for Biological Diversity reports. Among those lost included a tiny Hawaiian snail, one of the world’s largest freshwater fishes, three bird species, a shark, two frogs, and several plants. Frighteningly, the number of plants lost is probably in the thousands, due to the fact that scientists sometimes wait years or decades searching to ensure that a species is completely extinct.
The IUCN Red List of Threatened Species also helps people learn more about global extinction risk status of animal, fungus and plant species. Their list is still not nearly comprehensive of every species, Owen points out, but their inclusion of fungi and plants is critical in the discussion of what species are most at risk.
Which species are most at risk?
Animal conservation is not just about animals, and it’s not easy to determine what species we should focus on. When it comes to which species are most at risk, and therefore need most of our attention, the answer is complicated. “Some wildlife that pop into our heads when we think of critically endangered species are orangutans or rhinos. But in reality, when we talk about animal conversation, it’s tricky to try to simplify it like that,” Owen says. “For example, insects make up a huge portion of the biodiversity in our world. But it’s the mammals, these large charismatic animals that get the most attention, as well as birds.”
This is a dynamic I saw myself when I briefly worked at the Smithsonian National Zoo and Biology Conservation Institute. Visitors were mostly interested in donating, lured in by the idea of helping to save majestic tigers or exotic birds or cute pandas. But the discussion about conservation rarely extended towards insects, plants, or more traditionally “unsavory” animals like bats.
Jon Flanders, Director of Endangered Species Interventions at Bat Conservation International, says that’s why it can sometimes be difficult to engage the public on bat conservation. “Sometimes people persecute and hunt bats for different reasons. They’re nocturnal, found in dark places, and some people might be frightened. So there are lots of misunderstandings about them,” he says. “Bats are amazing, though. They’re so engaging once you know more about them.”
Owen says the reason for this disparity is rooted in what we’re drawn to. “It represents what people are most vocal about, what they care the most about.”
She says a useful tool in thinking about this is the classic Lion King example. “Lions depend on the gazelles, gazelles depend on grass, grass depends on the sun. That’s a simplification though, because in real ecosystems, biodiversity is what gives flexibility to these ecosystems. So, if the gazelles aren’t doing great, then the lions can shift to zebras or antelope.” But when there’s no biodiversity because the rate of extinction is so high, those options dwindle and everything becomes infinitely more at risk.
This is why we can’t afford to not care about all species — including plants and insects. Half of the one million species at risk are insects, and they provide crucial ecosystem services that we could not live without, especially pollination, nutrient cycling and pest control. The elimination of these ecosystem services would destroy our food supply, which would cause mass deaths from hunger and (further) global political instability due to the ensuing chaos.
Animal conservation can include hunting and fishing
While veganism is seen as a healthy choice for the environment — and in many ways it is, but it can also be very harmful — hunters and fishers are also part of the conservation movement. Hunter Morton, a Georgia-based outdoorsman, is enamored with the land and very much sees himself and his peers as part of animal conservation. Morton, who studied Agricultural Education in undergrad and is currently working on his masters in Wildlife Biology focusing on the history of African-American bird dog trainers in the South, argues that sportspeople play an important role in maintaining the environment.
“A lot of people see hunters and fishers as almost an enemy to wildlife, but hunters and fisherman are really the people that are on the ground helping efforts move forward for those endangered species and helping the ecosystem thrive,” says Morton.
Indigenous practices of hunting are about managing animal populations and subsistence, not sport or mass production. For example, lionfish are an invasive species that is threatening the ocean biodiversity in the Caribbean. So eating them is actually incredibly good for the environment, although it must be done properly, since the fish contain toxins. In Australian’s Western Desert, Aborginal hunters’ method of using fire to clear patches of land actually increases the population of the animals they hunt by “creating a mosaic of regrowth that enhances habitat.”
These methods could be adopted by more people, but the efforts should be led by those who have this ancestral connection to the land, because they have the deepest levels of knowledge. It’s also important to consult scientists about sustainable food choices, because some items that you may think are good for the Earth — like almond milk or soybeans — may actually be contributing to conditions that make animal conservation difficult, and we should rethink how or whether we consume them.
What can we do to stop it?
“As much as humans can be destructive, we can be a force for positive change as well,” Flanders said. For example, he says, in April 2017, partners in the U.S. and Mexico worked together to recover the lesser long-nosed bat, which was the first bat to ever be removed from the Endangered Species Act (ESA) protections. In addition to providing other ecosystem services, this bat is also responsible for the production of tequila, since it is pretty much the sole pollinator of agave, Flanders says. The recovery of the lesser long-nosed bat is a success story of recovery.
Flanders also said that creating resilient ecosystems is key.
“Creating environments that are resilient for bats and other species is critical, because things are changing too quickly for these animals to adapt. It’s not just the temperature changes but these sudden extreme events like monsoon, typhoons, droughts.”
One of the best ways to do that is engaging in climate justice efforts that aim to dismantle the fossil fuel industry, he says. For Owen, climate justice activism is a key part of addressing animal conservation. She currently works with Fridays for Future Toronto, as well as some independent activism work. “One of the biggest things we can do is listen to Black and Indigenous and other people for guidance. Indigenous people have been stewards of the land since time immemorial, they know what to do.”
“If your passion is something in agriculture and wildlife, say ‘Hey, this is what I want to do. I won’t let anybody take it from me,” says Morton, as a mentor to others who want to get involved in this work.
Owen also says when it comes to personal action, it’s crucial to “investigate whether those actions are just reducing your footprint or changing the world that is forcing you to live unsustainably.”
Animal conservation is a complicated issue, but it’s a core part of addressing the climate crisis and ensuring that the Earth is able to support all life, including human life. Animal conservation is also not limited to our favorite animals, like lions or giraffes. We have to care about all forms of life if we aim to protect it — from the largest elephants to the tiniest bacterium.
Experts say that we only have until 2030 to tackle the climate crisis before its worst effects consume us and make it pretty much impossible for human life to be sustained on this planet long-term. That sounds really terrifying because it is. But by fighting for animal conservation, we can make meaningful change, and ensure a place for our descendants on this beautiful planet.
We want to make life better for wild animals.
Although the natural world is a source of great beauty and happiness, vast numbers of animals routinely face serious challenges such as disease, hunger, or natural disasters. There is no “one-size-fits-all” solution to these threats. However, even as we recognize that improving the welfare of free-ranging wild animals is difficult, we believe that humans have a responsibility to help whenever we can.
Wild Animal Initiative currently focuses on helping scientists, grantors, and decision-makers investigate important and understudied questions about wild animal welfare. Our work catalyzes research and applied projects that will open the door to a clearer picture of wild animals’ needs and how to enhance their well-being. Ultimately, we envision a world in which people actively choose to help wild animals — and have the knowledge they need to do so responsibly.
10 Easy Things You Can Do To Save Endangered Species
1. Learn about endangered species in your area. Teach your friends and family about the wonderful wildlife, birds, fish and plants that live near you. The first step to protecting endangered species is learning about how interesting and important they are. Our natural world provides us with many indispensable services including clean air and water, food and medicinal sources, commercial, aesthetic and recreational benefits.
2. Visit a national wildlife refuge, park or other open space. These protected lands provide habitat to many native wildlife, birds, fish and plants. Scientists tell us the best way to protect endangered species is to protect the places where they live. Get involved by volunteering at your local nature center or wildlife refuge. Go wildlife or bird watching in nearby parks. Wildlife related recreation creates millions of jobs and supports local businesses.
3. Make your home wildlife friendly. Secure garbage in shelters or cans with locking lids, feed pets indoors and lock pet doors at night to avoid attracting wild animals into your home. Reduce your use of water in your home and garden so that animals that live in or near water can have a better chance of survival. Disinfect bird baths often to avoid disease transmission. Place decals on windows to deter bird collisions. Millions of birds die every year because of collisions with windows. You can help reduce the number of collisions simply by placing decals on the windows in your home and office.
4. Native plants provide food and shelter for native wildlife. Attracting native insects like bees and butterflies can help pollinate your plants. The spread of non-native species has greatly impacted native populations around the world. Invasive species compete with native species for resources and habitat. They can even prey on native species directly, forcing native species towards extinction.
5. Herbicides and pesticides may keep yards looking nice but they are in fact hazardous pollutants that affect wildlife at many levels. Many herbicides and pesticides take a long time to degrade and build up in the soils or throughout the food chain. Predators such as hawks, owls and coyotes can be harmed if they eat poisoned animals. Some groups of animals such as amphibians are particularly vulnerable to these chemical pollutants and suffer greatly as a result of the high levels of herbicides and pesticides in their habitat.
6. Slow down when driving. Many animals live in developed areas and this means they must navigate a landscape full of human hazards. One of the biggest obstacles to wildlife living in developed areas is roads. Roads divide habitat and present a constant hazard to any animal attempting to cross from one side to the other. So when you’re out and about, slow down and keep an eye out for wildlife.
7. Recycle and buy sustainable products. Buy recycled paper, sustainable products like bamboo and Forest Stewardship Council wood products to protect forest species. Never buy furniture made from wood from rainforests. Recycle your cell phones, because a mineral used in cell phones and other electronics is mined in gorilla habitat. Minimize your use of palm oil because forests where tigers live are being cut down to plant palm plantations.
8. Never purchase products made from threatened or endangered species. Overseas trips can be exciting and fun, and everyone wants a souvenir. But sometimes the souvenirs are made from species nearing extinction. Avoid supporting the market in illegal wildlife including: tortoise-shell, ivory, coral. Also, be careful of products including fur from tigers, polar bears, sea otters and other endangered wildlife, crocodile skin, live monkeys or apes, most live birds including parrots, macaws, cockatoos and finches, some live snakes, turtles and lizards, some orchids, cacti and cycads, medicinal products made from rhinos, tiger or Asiatic black bear.
9. Harassing wildlife is cruel and illegal. Shooting, trapping, or forcing a threatened or endangered animal into captivity is also illegal and can lead to their extinction. Don’t participate in this activity, and report it as soon as you see it to your local state or federal wildlife enforcement office.
10. Protect wildlife habitat. Perhaps the greatest threat that faces many species is the widespread destruction of habitat. Scientists tell us the best way to protect endangered species is to protect the special places where they live. Wildlife must have places to find food, shelter and raise their young. Logging, oil and gas drilling, over-grazing and development all result habitat destruction. Endangered species habitat should be protected and these impacts minimized.
By protecting habitat, entire communities of animals and plants can be protected together. Parks, wildlife refuges, and other open space should be protected near your community. Open space also provides us with great places to visit and enjoy. Support wildlife habitat and open space protection in your community. When you are buying a house, consider your impact on wildlife habitat.
Wildlife conservation is the preservation and protection of animals, plants, and their habitats. By conserving wildlife, we’re ensuring that future generations can enjoy our natural world and the incredible species that live within it. To help protect wildlife, it’s important to understand how species interact within their ecosystems, and how they’re affected by environmental and human influences.
Plants and animals have life events that seemingly occur like clockwork every year. Birds can migrate, mammals may hibernate, flowers bloom, and leaves change colors. The study of how the biological world times these natural events is called phenology. Scientists now understand that plants and animals take their cues from their local climate (long-term weather patterns). Climate is impacted by non-biological factors—temperature, precipitation, and available sunlight. Species use the predictable yearly changes in the climate to determine when they start natural events such as breeding or flowering.
Climate change is slowly increasing average annual temperatures. One of the most noticeable ways that climate change is impacting wildlife is by disrupting the timing of natural events. With warmer temperatures, flowering plants are blooming earlier in the year and migratory birds are returning from their wintering grounds earlier in the spring. Phenology is an important subject for conservationists to study because it helps us understand the patterns of specific species and overall ecosystem health. Every species has an impact on those in its food chain and community, and the timing of one species’ phenological events can be very important to the survival of another species.
Food Webs and Bioaccumulation
The energy we receive from food can be traced back to the sun. As the sun shines, it radiates light energy. Plants absorb the light energy, convert it to sugars (photosynthesis), and produce energy for other wildlife. The energy from the sun moves its way through ecosystems by predators eating their prey. A food web breaks down how all the producers, consumers, and decomposers interact in an ecosystem and how energy is transferred between species.
When animals eat their prey, they consume more than just energy. They also absorb all the chemicals and nutrients inside the prey. Sometimes animals ingest pollutants that can become stored in their fat and tissues. Human-caused pollution has added heavy metals, oil, and industrial and pharmaceutical chemicals to the environment. Plants, fish, and other species absorb these toxins, and as they are eaten by predators, the toxins are then absorbed into the predators’ tissues. As the chain of predator and prey continues up the food web, the toxins become more concentrated and move higher and higher up the food web. The process that causes the concentration of a substance to increase as it moves up the food web is called bioaccumulation. The pollutants can have a disastrous effect on the food web and potentially kill species.
A natural disturbance is any event that causes a disruption to the current state of an ecosystem. Natural disturbances are caused by forces of nature, including weather, geology, and biological fluctuations. This may include fires, floods, earthquakes, diseases, and droughts. After a disturbance impacts an ecosystem, there can be devastation, but healthy ecosystems have an amazing ability to bounce back. Some ecosystems even depend on disturbances, such as the threatened longleaf pine ecosystem. Sometimes the ecosystem will go back to its former structure, with the same plant and animal species. Other times, the disturbance will create something new by allowing new species to populate the area.
Not all disturbances are natural. Human actions have contributed to many disturbances seen in ecosystems today. While natural disturbances happen on occasion, human disturbances are putting constant pressure on ecosystems and dramatically impacting species. Human disturbances, including clear-cutting, habitat fragmentation, and pollution, are continuously affecting ecosystems. The moment the ecosystem begins adjusting to one stress, another appears. Many ecosystems that we depend on are not given enough time to adapt to the new conditions. The natural cycle of disturbances—growth, dieback, and growth—cannot properly function because too many disturbances are putting pressure on the ecosystem at once.
Corridors and Flyways
Wild animals are always on the move. They move from place to place in search of food, mates, shelter, and water. Many animals do not have to move far in order to have all their needs met, but other animals—for example migratory birds, wolves, mountain lions, or butterflies—require much more space. Currently many species with large territories, including gray wolves, are threatened because habitat loss and fragmentation have limited their available space. Roads, fences, and buildings cut off habitat and force wildlife into smaller areas. Conservationists have to take into account the different spatial needs of wildlife when designing plans to protect them. They have to think about the territory size, different habitat types, and migration routes that wildlife need.
A wildlife corridor is a tract of land that connects different wildlife habitats (such as refuges, parks, or rivers) that might otherwise be separated by human development. Wildlife corridors provide many benefits to wildlife. With corridors, animals have a better opportunity of finding the basic necessities they need—food, water, shelter, and places to raise their young. Animals that require larger territories can access new habitats and maintain a healthy territory size. Wildlife corridors also promote genetic biodiversity. When more individuals of a species are interconnected, the gene pool becomes larger and more viable. Migratory wildlife benefit from corridors because they can move safely over long distances without having to come into contact with human developments or cars. Species are more likely to survive disturbances by having more undisturbed areas.
The National Wildlife Federation, in partnership with the Santa Monica Mountains Fund, is working to create a wildlife crossing for mountain lions in California. By linking protected habitat on either side of a freeway, mountain lions and other wildlife can the access to green space they need to survive. The Liberty Canyon Wildlife Crossing, when built, will be the largest such crossing in the world, and a model for urban wildlife conservation.
Unlike mammals, birds and butterflies travel from one place to another by flying, so they face different kinds of challenges. Not only do we have to protect their winter and summer habitat, but also key rest stops that migratory wildlife use along the way. Conservationists can help threatened bird and butterfly populations by protecting habitat along major migratory flyways—pathways used by migratory birds and insects. Birds tend to take predictable routes to get from the winter feeding grounds to the summer breeding grounds and back. Flyways usually occur along coastlines, major rivers, and near mountains. The United States has four main migratory flyways.
-Pacific Flyway: Along the Pacific coast, west of the Rocky Mountains
-Central Flyway: Over the Great Plains, east of the Rocky Mountains
-Mississippi Flyway: Along the Mississippi River
-Atlantic Flyway: Along the Atlantic coast
A great way to help birds and butterflies migrate is by building a Certified Wildlife Habitat® in your backyard or balcony. Learn how to provide a critical resting place and food source to help migratory birds reach their destination.
The Real Case for Saving Species: We Don’t Need Them, But They Need Us
Conservationists argue that humans need to save species in order to save ourselves. The truth is we could survive without wild species — but they can’t survive without us, and the moral argument for protecting them and the beauty they bring to the world is overwhelming.
Irecently visited a museum exhibit on big cats. A sign featuring a beautiful jaguar asked, “Why should we care about wild cats?” Its answer: “Because in protecting big cats, we are protecting ourselves.”
Is that really true? That implies big cats are in trouble because “we” don’t care to protect ourselves. And if it turns out that we don’t really need jaguars in order to protect ourselves, have they lost their case for existence?
For decades, many conservationists have been trying to sell a clumsy, fumbling appeal to self-interest: the idea that human beings need wild nature, need wild animals, need the species on endangered lists. “If they go extinct, we’ll go extinct,” is a common refrain. The only problem: it’s false.
We drove the most abundant bird in the Americas — the passenger pigeon — to extinction. The most abundant large mammal — the American bison — to functional extinction. We gained: agriculture, and safety for cows, from sea to shining sea. Who misses the Eskimo curlew? Indeed, who knows they existed, their vast migrating flocks like smoke on the now-gone prairies? That experiment is done.
Billions of people want what you and I got in exchange: health and wealth and education. We now live the way most other people on the planet wish to live. Governments, institutions, and regular people have cheered the material expansion that has cost many species (and tribal peoples) everything. We have endangered species not because what is bad for them is bad for us, but because the opposite is true: what is bad for them has fueled the explosive growth and maintenance of human populations and technologies. We are losing many species along the way to humanity’s only three apparent real goals: bigger, faster, more. Propelling the human juggernaut has entailed wiping many species out of the way. People live at high densities in places devoid of wild species and natural beauty. Human beings have thrived by destroying nature. When the animals and open spaces go, we have industrial-scale farms and factories, ball fields and strip malls and quick-lubes. How could saving this or that endangered species, that is following those whose oblivion brought fast food and sneakers, be a matter of — of all things — saving ourselves? Telling people that “we” need jaguars to “protect ourselves?” That’s a hard sell. We don’t need them.
I can’t name a single wild species whose total disappearance would be materially felt by, essentially, anyone.
There is no species whose disappearance has posed much of an inconvenience for civilization, not a single wild species that people couldn’t do without, fewer whose erasure would be noticed by any but a handful of die-hard conservationists or scientists. The irrelevance of wild things to civil society is why endangered species never make it into polls of top public priorities. I can’t name one wild species whose total disappearance would be materially felt by, essentially, anyone (you can easily function without having access to elephants, but if you misplace your phone for one whole day, it’s personal chaos). But I can effortlessly list various species from tigers to mosquitoes whose annihilation has been diligently pursued. Annihilation comes easy to Homo sapiens. What’s of little interest for us is coexistence.
I have seen with my own eyes that the role of elephants as ecosystem engineers affecting all animals on the African savannas matters not at all to people converting bushland into vulnerable subsistence gardens or, more decisively, into large commercial farms raising flowers destined for vases on the tables of Europe. Think of your favorite species. Gorillas? Sperm whales? Hyacinth macaws? Karner blue butterflies? Billions of people never give them a thought.
Only a tiny minority of people actually work with wild creatures, as ecologists, conservation biologists, wildlife rehabilitators, falconers, or even fishermen (oddly and not coincidentally I’ve been all of those.) On an average day, animals and plants must put up or be pushed out. In most countries, few wild things can “provide” to humans anything more valued than their carcasses. Many major American tree species have disappeared or nearly so (American elm, American chestnut, eastern hemlock, for instance). Ash trees are now disappearing and the main pain-point for humanity is nothing more than angst for the future of baseball bats.
Lest anyone misread me: this predicament is catastrophic.
It is of course true that the things that are bad for nature as a whole — degradation of land and soil, polluted water and air — are bad for people ultimately. A total breakdown of living systems would mean a breakdown of human economies, and indications are it likely will. But “ultimately” is very far down the line, long after we’ve lost all the big animals, wild lands, viable ocean habitats, and the world’s living beauty. The human juggernaut can continue to blow through rhinos, parrots, elephants, lions, and apes and hardly feel a breeze. The most charismatic species all stand at or near historic lows and humans are at our historic high, two facts that are sides of the same coin. Claiming that people depend on wild nature is nice, but dependence on wild nature ended, and not well, generations ago. What keeps most people going is farming felling, pumping, and mining.
Far down the line when the land is exhausted and there’s no water on an overheated planet, there may be a great reckoning. It’s easy enough to hear the rumbles now. But even the recent hurricanes and fires that have left communities seemingly beyond recovery have not shaken the deniers. In this country, government disdain for natural places and species, and official ennui about the human health effects of environmental degradation, are worst-ever. And the current rollbacks remain too weakly opposed; most people don’t feel affected. Most of wild nature could be gone long before the human species confronts an existential cliff.
What a grim world it will be by the time we’re down to what humans need. Human need is a very poor metric for evaluating the existence of living things.
The natural services humans actually need to fuel modern living come from microbes of decay, a few main insect pollinators, the ocean’s photosynthesizing plankton, and non-living things like water and the atmosphere. Eventually we may well simplify the world to the bare essentials, and it will still support billions more people. Indeed, that’s the only way it can.
What a grim world it will be by the time we’re down to what humans need. Which only shows that human need is a very poor metric for evaluating the existence of living things. Ask living creatures to justify their existence in terms of human need; they lose.
So, in what bleak terrain does this leave us? The law that has been called the gold standard of species protection, the U. S. Endangered Species Act, doesn’t begin to get interested until after a species, considered in isolation, is already in dire straits. Then it sets a floor, measuring success as mere existence. A wiser law would target an aspirational ceiling of robust, resilient populations across broad, intact scapes of viable lands and productive waters.
Yet when applied in good faith it works. It works because of something many environmentalists have forgotten, most average people never think about, and most politicians are incapable of learning: it works because it doesn’t ask a species to prove its usefulness, what they’re good for, or how much money they’re worth. The act doesn’t say that we need them. It acknowledges that we harm them. In its first words, “The Congress finds and declares that various species of fish, wildlife, and plants in the United States have been rendered extinct as a consequence of economic growth.” It says that recovery plans shall “give priority to… particularly those species that are, or may be in conflict with construction or other development projects or other forms of economic activity.”
Yet many conservationists continue trying to make the flimsy case that we need endangered species. And because the argument is false, it can be a counterproductive pandering to the self-interest of people who simply won’t care. “Prove that I need some endangered snail or whale.” You can’t.
Fortunately, you don’t have to. The argument was decided decades ago, by Congress on behalf of all Americans, in favor of what you and I care about. The Endangered Species Act doesn’t claim that our existence depends on the existence of wild species. It says that we, the people, don’t let species go extinct, that this is who we are. It’s not about practicality; it’s about morality. The moral compass of species stewardship or loss is already mainstream — loss is bad. Conservationists and rank-and-file nature lovers should not pick that scab by trying to show that nature can and must serve us. The law says we need to serve nature. That’s a lot to work with.
Of course, laws are only as strong as the support they have. Conservationists must not only remind themselves that the law guides policy based on moral principle; they must continue to make the wide case for that underlying moral principle. When people say, “What good are they. They’re in the way!,” conservation needs a stronger argument than an appeal to self interest. Self interest has already been considered and nature has lost. Oil palms make money; never mind orangutans. We don’t need orangutans in order to “protect ourselves.” Orangutans need us to protect them.
But how best to press the case for life on Earth?
Humans have considered ourselves the most moral of species. A moral species has moral obligations. Despite capitalism’s appeal to self-interest, religions continue to assert the primacy of right and wrong. It may be that in our social species the only thing capable of standing up to pure self-interest is moral suasion. But what religions have underplayed — and indeed some have disdained — is seeing the physical world as sacred. On this planet where astrobiologists detect no other life in the galaxy, the rarity and perhaps even uniqueness of life in the universe makes Earth a sacred place. All known meaning in the universe is generated here, because this is the only living planet.
Winning the war against the natural in pursuit of accelerated material living, we lose the beauty that makes living worthwhile.
Although wild nature is not necessary for human survival, it is necessary for human dignity. Some of the grimmest places for human existence are those where nature has been scorched. People can lose their dignity in various ways, including oppressive governments. But oppressive surroundings are sufficient.
Zoom out from “endangered species” to the big picture. Abundant multitudes of species, wild things in wild places, anchor beauty to the face of this planet. What is true is this: Wild things create and live in the remaining beautiful places. As wild animals disappear, what is lost is the world’s beauty. Winning the war against the natural in pursuit of accelerated material living, we lose the beauty that makes living worthwhile.
That is not trivial. It is the most profound thing on Earth.
Ecology — living relationships and reliances — may be the only concept containing sufficient scope for a future worth humanly living. Ecology is most easily perceived by this shorthand: natural beauty. Each of our senses has ways of informing us what is good and bad. Our sense of smell evolved to sense things good for us as smelling pleasant and bad as smelling putrid. Our mind evolved the ability to combine all our sense into one overall detector of what is good in the world, and that best overarching sense is what we call “beauty.” As the beauty of the world drains away, we become less than human in the long run. And part of the long run is now.
Beauty is the single criterion that best captures all our deepest concerns and highest hopes. Beauty encompasses the continued existence of free-living things, adaptation, and human dignity. Really, beauty is simple litmus for the presence of things that matter.
If a future reckoning arrives for the human species, as seems likely, it will come because we asked life to prove its value compared to ever-more corn and shopping discounts, but could not hear the real answer. It will come because we did not see our planetary miracle as sacred.
Endangered species and wild things in the remaining wild places need us to care for them not selfishly but selflessly, for their sake, the sake of everything and everyone who is not us, for the sake of beauty and all it implies. As we make our habitual appeals to practicality, the argument we cannot afford to ignore, the one that must frequently be on our lips, is this: We live in a sacred miracle. We should act accordingly.
Meanwhile, a few things are right. Within the last few weeks, the long-endangered Kirtland’s warbler came off the endangered species list. This didn’t happen because we needed them. It happened because the Endangered Species Act determined that when species need us, we shall go to their aid. It happened, the U.S. Fish and Wildlife Service announced, because, “Kirtland’s warbler has responded well to active management over the past 50 years.” Before the Endangered Species Act, the species was down to 200 singing males. The population has increased more than tenfold, not because we needed Kirtland’s warbler, but because we understood that Kirtland’s warbler needed us. We understood our moral responsibility and commitment to keep a tiny bird in the world with us. Many would say that the warbler doesn’t matter to us. But the people who won the argument on behalf of the bird were those who argued and acted on the premise that we mattered to the warbler. Nothing else could have worked.
Oust species to save ecosystems
Network models might offer solution to cascading species loss.
Could you prevent nine local extinctions by hastening one extinction? It sounds completely counterintuitive, but a pair of ecosystem modellers are proposing that conservationists could sometimes prop up a troubled ecosystem by removing one or more of its species — and using models to determine the timing and order of those removals.
The species that make up an ecosystem are connected in complex ‘food webs’ of eater and eaten. When one species disappears, its predators can no longer eat it and its prey are no longer eaten by it. Changes in these populations affect others. Such impact ‘cascades’ can be unpredictable and sometimes catastrophic.
Sagar Sahasrabudhe and Adilson Motter of Northwestern University in Evanston, Illinois, have shown that in several model food webs, as well as in two webs modelled with data derived from real ecosystems — the Chesapeake Bay off Maryland and Virginia and the Coachella Valley in Southern California — removing or partially suppressing one or more species at key time points after one member has gone extinct saves other members of the web from local extinction. They publish the results today in Nature Communications1.
The idea relies on the fact that ecosystem networks can often shift to a different stable arrangement after losing members. “Ecological systems are quite robust, actually,” says Motter. The famous “balance of nature” is perhaps better understood as the “multiple possible balances of nature”. But the order of removals matters.
Remove A and then B, for example, and a given web might change shape but retain all its other members; remove B and then A, however, and the cascade of changes drives many of the other members extinct.
In very simple webs, the impacts can be easy to follow. For example, the removal of a large predator could allow a medium-sized predator to increase in numbers and eat its smaller mammal and bird prey into extinction. In this case, keeping a lid on the numbers of the medium-sized predator would prevent these extinctions.
But even small webs can harbour complexities that can make the order of removals for ecosystem stability challenging to sort out. Motter likes the story of the island foxes (Urocyon littoralis) on the Channel Islands off the coast of California, which is recorded in the study. When feral pigs were introduced to the islands, they attracted golden eagles that preyed on both pigs and foxes. Fox numbers then dropped. Removing the pigs would have left the foxes as the sole diet of the eagles, and likely doomed them. So instead, conservationists captured and relocated the eagles and only then eradicated the pigs. The fox population is now recovering.
“The same actions at different times have very different consequences,” says Motter.
In more complex webs, the key species that needs to be removed or suppressed to head off more serious collapse isn’t intuitively clear. But, by modelling a variety of food webs using established ecological principles, the researchers were able to find such species and they hope that the algorithms that they created might eventually be able to identify target species in the real world.
Factoring in complexity
However, the results will only be accurate if the real ecosystem is well represented by the model. In their food-web modelling, Sahasrabudhe and Motter have used accepted ecological models of predator-prey relationships, but a more elaborate representation of an ecosystem would also include parasitism, seed dispersal, competition, mutualisms (in which species make life easier for each other), nutrient dynamics and more. And to include such complex detail in a model, scientists will first have to go out and gather that information in the field. Who is eating whom? Who is pollinating whom?
When the algorithms point to an exotic species as a target for removal or suppression, conservationists are likely to have little problem with the idea. But if a native species is the proposed target, that will go against many conservationists’ impulses to protect rather than remove.
Neo Martinez, director of the non-profit Pacific Ecoinformatics and Computational Ecology Lab in Berkeley, California, says that Sahasrabudhe and Motter’s ideas are exciting, but the conservatism of conservation means that they won’t be relied on in isolation, at least not right away. “Because of the lack of realism — we don’t include everything in these models — no one is going to make an important conservation decision solely on these models. That is a long time in the future.”
But a long time in the future isn’t never. Martinez says that whereas six or eight years ago ecologists generally considered ecosystems too complex to ever be productively modelled, not unlike the stock market, today modellers are gaining confidence.
Motter agrees. “In the long run, I think we will have people in the field advocating for the suppression of native species.” He points out that land managers are already doing so, less systematically, by running regulated hunting of prey species in areas where top predators have been extirpated. Human impacts are just too great on most ecosystems, he says, for us to just hope they will sort themselves out. “In the presence of perturbations, it is reasonable to consider compensatory perturbations,” he says.
What Happens When Something in a Food Chain Goes Extinct?
All living organisms hold a place in the food chain, structured around the transfer of life-sustaining energy through an ecosystem: from sunlight to plant to rabbit to bobcat to maggot, to make a simple example. Because this energy transfer involves members of the food chain interacting with one another and their environment in a complex, interlocking ecological system, extinction of one species can have a cascading effect on others.
Increased Population of Prey
When a predatory species becomes threatened or extinct, this removes a check and balance in the food chain on the population of prey previously consumed by that predator. Consequently, the prey population can explode. For instance, the huge increase in white-tailed deer populations in the central and eastern U.S. in the latter half of the 20th century likely stemmed partly from reduced or altogether eliminated populations of deer predators, namely wolves and cougars. Overbrowsing as a result of such excessive deer numbers can transform the makeup of plant communities and negatively impact forest regeneration.
I think this concept is a little like playing God. Every time we think we know more than Mother Nature we end up messing things up royally. How many times have rthe Army Corps of Engineers tried to affect changes to our environment only to cuase greater harm than good? There is an old saying “two wrongs don’t make a right.”
Ripple Effect on Other Species
Endangerment or extinction of one species can threaten the viability of another species. In Britain, for instance, the red ant population plummeted as the result of fewer sheep grazing in pastures; sheep had previously kept the grass short, the red ant’s habitat preference. In turn, the paucity of red ants led to the extinction of a large butterfly species that eats red-ant eggs as part of its life cycle. Food chain disruptions from the loss of a single species can be ecosystem-wide, too: When sea otters decline, populations of sea urchins, a preferred otter food, can explode. The resulting overpopulation of kelp-munching urchins, meanwhile, can reduce kelp forests, threatening numerous marine species that rely on this habitat.
Overall ecosystem instability due to reduced biodiversity ranks among the consequences of species extinctions. As the number of species in a food chain decreases, there are fewer sustainable alternatives for members of the food chain that had depended on the extinct species. Biodiversity also lends genetic variability to a population, helping it adapt to fluctuating environmental conditions. For instance, a study of tropical rain forests in West Africa conducted by ecologists at Leeds University between 1990 and 2010 suggested that biodiversity mitigates the effects of climate change and helps tree species adapt to drought conditions.
Extinction of animal or bird species in the food chain may alter the physical environment as well. For instance, accidental introduction of the predatory brown tree snake to Guam wiped out 10 of the 12 native bird species on the island causing collateral damage to the forest, according to a University of Washington study. Biologists found that extinction of the birds had adversely impacted tree pollination, seed germination and seed dispersal. Without birds to spread seeds, there may only be a few clumps of mono-species trees in Guam’s future, fundamentally changing forest habitat.
How would a species’ extinction impact the food web, our ecosystems?
Every living thing plays a role in the food chain and Earth’s ecosystems, and the extinction of certain species, whether predators or prey, can leave behind significant impacts.
“Since the origin of life on Earth, it’s fair to say that more species have gone extinct than are currently alive now,” said Dr. Anthony Giordano, president and chief conservation officer of the Society for the Preservation of Endangered Carnivores and their International Ecological Study (SPECIES). “Extinction itself is part of the normal course of evolution.”
The effect a species would have if it were to fade from existence depends largely on its role in the ecosystem. Predators, for example, are often the first to be threatened by hunting or competition with people and resources, said Clemson University conservation biologist Dr. Robert Baldwin.
“Think about large animals like the grizzly bear,” Baldwin said. “When a predator goes extinct, all of its prey are released from that predation pressure, and they may have big impacts on ecosystems.”
The loss of a predator can result in what is called a trophic cascade, which is an ecological phenomenon triggered by a predator’s extinction that can also impact populations of prey, which can cause dramatic ecosystem and food web changes.
“If there are too many deer, for example, they can really change the ecosystem because they can destroy forests, and they also carry disease,” Baldwin said.
Scientists have noted the trophic cascade effect in parts of Africa where lion and leopard populations have dwindled, according to Smithsonian Magazine. It caused olive baboons to alter their behavior patterns and increase contact with nearby humans. The increased contact has led to a rise in intestinal parasites in both people and the baboons.
In the case of the northern white rhino, of which only two female rhinos now survive, the last male of the species was held in semi-captivity at the end of its life, and “the damage was already done in the ecosystem by that point,” Baldwin said.
However, in general, the loss of rhinos, which often face threats from humans, from the ecosystem can have wide-ranging effects, according to Baldwin, who noted that the rhino’s eating pattern helps with seed dispersal.
“They eat grasses and vegetation in one place, and they move and defecate in another place,” he said. “That helps those plants to disperse throughout the ecosystem, and it also helps populate the ecosystem with rhino food.”
The loss of abundant organisms that provide food for a wide variety of species would also interrupt the food web, according to Baldwin.
“For instance, if krill in the ocean goes extinct or becomes depressed in numbers, then that’s the bottom-up effect; predators that rely on krill will suffer,” he said.
While not at the top of the food chain, sea otters are keystone predators in the kelp forests in which they reside.
“The presence of sea otters in marine near-shore communities and coastal communities, particularly on the West Coast, have been shown to be essential and critical to healthy kelp forests underwater,” Giordano said.
North American whales face potential extinction as warming oceans force them into unsafe territory
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These kelp forests provide habitat for many species. “One of the ways sea otters help to maintain those kelp forests is by preying upon other species that would slowly start to eat or consume the kelp, which, if they were left unchecked, would then rattle the entire kelp bed and turn it into a rocky or barren wasteland,” Giordano said.
Species like parrot fish, which graze on algae, are extremely important to coral reef ecosystems because they prevent algae growth from getting out of control and impacting those coral reefs, according to Giordano.
“As algae expands in those communities, it can lead to the expansion of coral dead zones,” he added.
The loss of certain species can impact the ecosystem in a number of ways, Giordano said, but the issue is that researchers don’t yet know about many of the species out there.
A 2011 study concluded that about 86 percent of the Earth’s species have yet to be discovered, according to National Geographic.
“We know more about some of the larger ones, but for many species, especially the ones that are disappearing, we don’t know the impact of their loss,” he said.
Loss of large predators has caused widespread disruption of ecosystems
Scientists say decimation of top consumers may be “humankind’s most pervasive influence on the natural world” due to cascading effects on ecosystems
The decline of large predators and other “apex consumers” at the top of the food chain has disrupted ecosystems all over the planet, according to a review of recent findings conducted by an international team of scientists and published in the July 15 issue of Science. The study looked at research on a wide range of terrestrial, freshwater, and marine ecosystems and concluded that “the loss of apex consumers is arguably humankind’s most pervasive influence on the natural world.”
According to first author James Estes, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, large animals were once ubiquitous across the globe, and they shaped the structure and dynamics of ecosystems. Their decline, largely caused by humans through hunting and habitat fragmentation, has had far-reaching and often surprising consequences, including changes in vegetation, wildfire frequency, infectious diseases, invasive species, water quality, and nutrient cycles.
The decline of apex consumers has been most pronounced among the big predators, such as wolves and lions on land, whales and sharks in the oceans, and large fish in freshwater ecosystems. But there have also been dramatic declines in populations of many large herbivores, such as elephants and bison. The loss of apex consumers from an ecosystem triggers an ecological phenomenon known as a “trophic cascade,” a chain of effects moving down through lower levels of the food chain.
“The top-down effects of apex consumers in an ecosystem are fundamentally important, but it is a complicated phenomenon,” Estes said. “They have diverse and powerful effects on the ways ecosystems work, and the loss of these large animals has widespread implications.”
Estes and his coauthors cite a wide range of examples in their review, including the following:
-The extirpation of wolves in Yellowstone National Park led to over-browsing of aspen and willows by elk, and restoration of wolves has allowed the vegetation to recover.
-The reduction of lions and leopards in parts of Africa has led to population outbreaks and changes in behavior of olive baboons, increasing their contact with people and causing higher rates of intestinal parasites in both people and baboons.
-A rinderpest epidemic decimated the populations of wildebeest and other ungulates in the Serengeti, resulting in more woody vegetation and increased extent and frequency of wildfires prior to rinderpest eradication in the 1960s.
-Dramatic changes in coastal ecosystems have followed the collapse and recovery of sea otter populations; sea otters maintain coastal kelp forests by controlling populations of kelp-grazing sea urchins.
-The decimation of sharks in an estuarine ecosystem caused an outbreak of cow-nosed rays and the collapse of shellfish populations.
Despite these and other well-known examples, the extent to which ecosystems are shaped by such interactions has not been widely appreciated. “There’s been a tendency to see it as idiosyncratic and specific to particular species and ecosystems,” Estes said.
One reason for this is that the top-down effects of apex predators are difficult to observe and study. “These interactions are invisible unless there is some perturbation that reveals them,” Estes said. “With these large animals, it’s impossible to do the kinds of experiments that would be needed to show their effects, so the evidence has been acquired as a result of natural changes and long-term records.”
Estes has been studying coastal ecosystems in the North Pacific for several decades, doing pioneering work on the ecological roles of sea otters and killer whales. In 2008, he and coauthor John Terborgh of Duke University organized a conference on trophic cascades, which brought together scientists studying a wide range of ecosystems. The recognition that similar top-down effects have been observed in many different systems was a catalyst for the new paper.
The study’s findings have profound implications for conservation. “To the extent that conservation aims toward restoring functional ecosystems, the reestablishment of large animals and their ecological effects is fundamental,” Estes said. “This has huge implications for the scale at which conservation can be done. You can’t restore large apex consumers on an acre of land. These animals roam over large areas, so it’s going to require large-scale approaches.”
Why Endangered Species Matter
The Endangered Species Act (ESA) was established in 1973 to protect “imperiled species and the ecosystems upon which they depend” and help them recover.
The Trump administration has put forth a number of proposals that would weaken the ESA. These include measures to allow for the consideration of economic impacts when enforcing the ESA, ending the practice of automatically giving threatened species the same protection as endangered species, and making it easier to remove species from the endangered list.
In a way, this is nothing new because the ESA has been under attack for decades from construction, development, logging, water management, fossil fuel extraction and other industries that contend the act stifles economic development. But between 2016 and 2018 alone, there were almost 150 attempts to undercut the ESA; and last year, from July 8 to 22, Republicans in Congress or the Trump administration introduced 24 such measures and spending bill riders.
These bills included efforts to remove the gray wolf’s protected status in Wyoming and the western Great Lakes; a plan to remove from the endangered list the American burying beetle that lives on oil-rich land; and a strategy to roll back protection of the sage-grouse, which also inhabits oil-rich land in the West and whose numbers have declined 90 percent since the West was first settled. The Trump Administration recently opened up nine million acres of sage-grouse habitat to drilling and mining.
Endangered species, if not protected, could eventually become extinct—and extinction has a myriad of implications for our food, water, environment and even health.
Extinction rates are accelerating
Ninety-nine percent of all species that have ever lived have gone extinct over the course of five mass extinctions, which, in the past, were largely a result of natural causes such as volcano eruptions and asteroid impacts. Today, the rate of extinction is occurring 1,000 to 10,000 times faster because of human activity. The main modern causes of extinction are the loss and degradation of habitat (mainly deforestation), over exploitation (hunting, overfishing), invasive species, climate change, and nitrogen pollution.
There are also other threats to species such as the pervasive plastic pollution in the ocean—a recent study found that 100 percent of sea turtles had plastic or microplastic in their systems.
Emerging diseases affecting more and more wildlife species such as bats, frogs and salamanders are the result of an increase in travel and trade, which allows pests and pathogens to hitch rides to new locations, and warming temperatures that enable more pests to survive and spread. Wildlife trafficking also continues to be a big problem because for some species, the fewer members there are, the more valuable they become to poachers and hunters.
How many species are endangered?
According to the International Union for Conservation of Nature’s Red List of Threatened Species, over 26,500 species are in danger of extinction. This includes 40 percent of amphibians, 34 percent of conifers, 33 percent of reef-building corals, 25 percent of mammals and 14 percent of birds. In the U.S., over 1,600 species are listed as threatened or endangered.
A 2018 report by the Endangered Species Coalition found that ten species in particular are “imperiled” by the Trump administration’s proposals: California condor, giraffe, Hellbender salamander, Humboldt marten, leatherback and loggerhead sea turtles, red wolf, rusty patched bumble bee,
San Bernardino kangaroo rat, West Indian manatee, and Western yellow-billed cuckoo.
The web of life
While it may seem unimportant if we lose one salamander or rat species, it matters because all species are connected through their interactions in a web of life. A balanced and biodiverse ecosystem is one in which each species plays an important role and relies on the services provided by other species to survive. Healthy ecosystems are more productive and resistant to disruptions.
A recent study found that extreme environmental change could trigger an “extinction domino effect.” One of the study’s authors said, “Because all species are connected in the web of life, our paper demonstrates that even the most tolerant species ultimately succumb to extinction when the less-tolerant species on which they depend disappear.” So saving one species means saving its habitat and the other species that live there too.
“When you lose one species, it affects the ecosystem and everything around it gets a little bit more fragile while it adapts to change,” said Kelsey Wooddell, assistant director of the Earth Institute Center for Environmental Sustainability. “Even if it’s not a keystone species [a species that others in an ecosystem depend on], its loss will weaken the functionality of the entire ecosystem, which just makes it easier for that ecosystem to stop working.”
What are the consequences of extinction?
Altering ecosystems through cascading effects
If a species has a unique function in its ecosystem, its loss can prompt cascading effects through the food chain (a “trophic cascade”), impacting other species and the ecosystem itself.
An often-cited example is the impact of the wolves in Yellowstone Park, which were hunted to near extinction by 1930. Without them, the elk and deer they had preyed upon thrived, and their grazing decimated streamside willows and aspens, which had provided habitat for songbirds. This left the stream banks susceptible to erosion, and a decline in songbirds allowed mosquitoes and other insects the birds would have eaten to multiply. When the wolves were reintroduced to the park in 1995, they once again preyed on the elk; plant life returned to the stream banks and along with it, birds, beavers, fish and other animals. (Note: David Bernhardt, acting secretary of the Department of the Interior, just announced a proposal to strip gray wolves of their endangered status in the Lower 48 states.)
Kelp forests are another classic example. They play an important role in coastal ecosystems because they provide habitat for other species, protect the coastline from storm surges and absorb carbon dioxide.
Yet kelp forests are rapidly getting mowed down by exploding numbers of purple sea urchin. California sea otters eat the purple sea urchins that feed on giant kelp. These otters used to number in the hundreds of thousands to millions, but their population has been reduced to about 3,000 as a result of unchecked hunting in the 19th century and pollution. Moreover, in 2013 the sunflower starfish, which also eats purple sea urchins, began dying because of a virus that was likely exacerbated by warmer waters. Without the sea otter and the sunflower starfish predators, the purple sea urchin began feasting on the kelp forests, which declined 93 percent between 2013 and 2018. (A new study found that kelp forests are now also threatened by ocean heat waves.) The explosion of sea urchins not only damaged the kelp ecosystem, it also had serious impacts on Northern California’s red urchins that are valued for sushi. Fish that need the kelp forests for spawning, such as sculpin, rock cod and red snapper may become vulnerable in the future as well.
As another example, Wooddell explained that on Guam, after the invasive brown tree snake was accidentally introduced to the island in the 1950s, 10 of the island’s 12 endemic bird species went extinct. “Typically birds eat seeds and spread seeds elsewhere on the island but that is no longer a functioning ecosystem,” she said. “So the forest and the trees have decreased a lot. And Guam is covered in spiders because the birds are not there to eat them.”
Losing apex species has multiple effects
Eliminating the large predators at the top of the food chain, the “apex species,” may be humans’ most serious impact on nature, according to one study. These large species are more vulnerable because they live longer, reproduce more slowly, have small populations, and need more food and a greater habitat area. Scientists say their loss has played a role in pandemics, fires, the decline of valued species and the rise of invasive ones, the reduction of ecosystem services, and decreased carbon sequestration.
Elephants are an apex species that may go extinct in our lifetime, as a result of tourism, habitat loss and poaching for ivory. This could dramatically change ecosystems in Africa and Asia. Through consumption and digestion, elephants disperse more seeds farther than any other animals; this fosters the growth of plants and trees that birds, bats and other animals depend upon for food and shelter.
The loss of apex species can also affect wildfires. After rinderpest, an infectious virus, wiped out many plant-eating wildebeest and buffalo in East Africa in the late 1800s, plants flourished. During the dry season, this over-abundance of vegetation spurred an increase in wildfires. In the 1960s, after rinderpest was eliminated through vaccinations, the wildebeest and buffalo returned. The ecosystem went from shrubbery to grasslands again, decreasing the amount of combustible vegetation, and the wildfires decreased.
Seventy-five percent of the world’s food crops are partially or completely pollinated by insects and other animals, and practically all flowering plants in the tropical rainforest are pollinated by animals. The loss of pollinators could result in a decrease in seed and fruit production, leading ultimately to the extinction of many important plants.
Flying foxes, also known as fruit bats, are the only pollinators of some rainforest plants. They have been over-hunted in tropical forests with several species going extinct. One study noted that 289 plant species, including eucalyptus and agave, rely on flying foxes to reproduce; in turn, these plants were responsible for producing 448 valuable products.
Bees pollinate over 250,000 species of plants, including most of the 87 crops that humans rely on for food, such as almonds, apples and cucumbers.
But in recent years, large populations of bees have been wiped out by the mysterious “colony collapse disorder” wherein adult honeybees disappear from their hive, likely in response to numerous stressors.
Over the last 20 years in the U.S., monarch butterflies, which pollinate many wildflowers, have decreased 90 percent. The rusty-patched bumble bee, another important pollinator and the first bee species to be put on the endangered list, now only occupies one percent of its former range.
Insect populations overall are declining due to climate change, habitat degradation, herbicides and pesticides. A 2014 review of insect studies found that most monitored species had decreased by about 45 percent. And a German study found 75 percent fewer flying insects after just 27 years. As insect populations are reduced, the small animals, fish and birds that rely on them for food are being affected, and eventually the predators of fish and birds will feel the impacts as well. One entomologist who had studied insects in the rainforest in the 1970s returned in 2010 to find an up to 60-fold reduction. His study reported “a bottom-up trophic cascade and consequent collapse of the forest food web.”
Endangering the food chain
Plankton, tiny plant and animal organisms that live in the ocean or fresh water, make up the foundation of the marine food chain. Phytoplankton are critical to the health of oceans and the planet because they consume carbon dioxide and produce oxygen during photosynthesis.
In 2010, researchers found that phytoplankton had decreased 40 percent globally since 1950, and attributed the decline to rising sea surface temperatures. The scientists speculated that the warming surface waters did not mix well with the cooler, deeper waters rich in nutrients that phytoplankton need. In addition, zooplankton are very sensitive to slight changes in the amount of oxygen in the ocean, and may be unable to adapt as areas of low oxygen expand due to climate change.
The quantity and quality of plankton also affects the nutrition of other creatures further up the food chain. In the Mediterranean Sea, the biomass of sardines and anchovies declined by one-third in just ten years. One scientist speculated that this is because the sardines’ and anchovies’ normal plankton had disappeared, so they had to resort to eating a less nutritious species of plankton with fewer calories. Changes in plankton quality could be a result of water temperature, pollution or lack of nutrients, but scientists are not exactly sure why the plankton makeup in some places is changing. If it is due to global warming and pollution, some say the situation could worsen.
However, Sonya Dyhrman, a professor in Columbia University’s Department of Earth and Environmental Sciences who studies phytoplankton with the Lamont-Doherty Earth Observatory, is more sanguine about the future. “Microbes like phytoplankton can adapt, can acclimate, and can evolve, so I worry less about lineages of phytoplankton going extinct and more about how phytoplankton community composition will change in the future ocean,” said Dyhrman.
A different community composition of phytoplankton could change the food web structure, but Dyhrman is not really worried about the total collapse of fisheries. She is concerned, however, that “there could be changes in ocean ecosystems and we don’t really know what those changes will be. What will the architecture of that ecosystem look like in the future? The problem is, the ocean is already changing and we don’t understand the architecture of the ecosystem right now well enough to predict what will happen in the future.“
Losing nature’s therapeutic riches
More than a quarter of prescription medications contain chemicals that were discovered through plants or animals. Penicillin was derived from a fungus. Scientists are studying the venom of some tarantulas to see if one of its compounds could help cure diseases such as Parkinson’s. One molecule from a rare marine bacterium could be the basis of a new way to treat to melanoma.
Scientists have so far identified about 1.7 million different types of organisms, but between 10 and 50 million species are thought to exist on Earth.
Who knows what substances or capabilities some of these species might possess that could help treat diseases and make human lives easier?
According to a study for the U.N., the continued loss of species could cost the world 18 percent of global economic output by 2050.
Already, a number of industries have been economically impacted by species loss. The collapse of bee populations has hurt many in the $50 billion-a-year global honey industry. Atlantic cod in the waters off of Newfoundland formed the basis of the local economy since the 15th century — until overfishing the cod destroyed the livelihoods of local fishermen.
What you can do about extinction
Extinction is hard to see. We may not realize how much of the natural world has been lost because the “baseline” shifts with every generation. Past generations would regard what we see as natural today as terribly damaged, and what we see as damaged today, our children will view as natural.
Wooddell believes the most important thing one can do is to put pressure on Congress and elected leaders to create land management, pollution and other sustainable policies that will protect biodiversity and the environment. However, because it’s unlikely that these kinds of top-down policies will be instituted in the current political climate, she recommends mobilizing grassroots community groups to create “bottom-up” policies.
Here are some other things you can do to protect endangered species and prevent extinction:
-Eat less meat. Soybean production is one of the main causes of deforestation, and most soybean meal is used for animal feed.
-Buy organic food because organic farmers use only non-synthetic or natural pesticides on their crops. Synthetic pesticides may be toxic for other organisms.
-Choose sustainable seafood. The Marine Stewardship Council provides a list of certified sustainable fish for responsible eating.
–Compost food waste. In New York City, the compost is used for urban farming and gardening, which provide habitat for pollinators.
-Buy wood and paper products certified by the Forest Stewardship Council, to ensure they’re harvested from responsibly managed forests.
-Don’t buy products made from endangered or threatened species, such as tortoise shell, ivory, coral, some animal skins, and “traditional” medicines.
-Be aware of the source of palm oil used in countless food and cosmetic products. Many tropical forests are being razed for palm oil plantations. If a product contains palm oil, make sure it’s from a deforestation-free plantation.
-If you have a garden, plant native shrubs and flowers that attract butterflies and other pollinators. Milkweed is particularly helpful for monarch butterflies.
-Diversify your diet. Eating these 50 foods will promote biodiversity and a healthier plant.
-Support and get involved with organizations that are helping endangered animals.
-Join the Center for Biological Diversity and use their Take-Action Toolboxes.
Correction: This post was updated on April 3, 2019 to remove a sentence about cownose rays devastating scallop populations off of North Carolina. It turns out that other studies have challenged those findings.
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Tiger Expert Answers Questions About Netflix’s Tiger King
With its larger-than-life characters, Netflix’s docu-series “Tiger King” put a controversial spin on a real problem — breeding tigers for profit has created an animal welfare, public safety and law enforcement nightmare in the U.S. As this series and a number of investigative reports that preceded it have shown, America has a big and growing captive tiger crisis right in its own backyards, but it pales in comparison to the one facing endangered wild populations. In this blog, Panthera Chief Scientist and Tiger Program Director Dr. John Goodrich talks about the threats facing wild tigers and why we need to advocate for them now more than ever.
What is the status of tigers in the wild?
Only about 4,000 tigers remain in the wild, as opposed to about 100,000 a century ago. To provide some context, by some estimates there are more than twice as many tigers living in roadside zoos in the U.S. than there are left in the wild.
What are the main reasons tigers are declining in the wild?
Their decline is the result of poaching and habitat loss, with poaching being the top threat today, driven by a very high black-market price for their parts, primarily for Traditional Asian Medicine. This poaching and the multi-billion dollar trade that drives it are illegal in every single tiger range state.
To help visualize the magnitude of the poaching problem, imagine an area roughly the size of France and Spain combined — around 1 million km of tiger habitat — sitting vacant, emptied of tigers and their prey. Due to poaching, tigers have gone extinct in Vietnam, Laos and Cambodia just in the past 15 years.
The second biggest threat to tigers is habitat loss. Tigers occupy some of the most densely populated countries in the world that are experiencing some of the greatest deforestation rates in the world.
What are the solutions?
The solutions are simple, at least conceptually. Tigers are a resilient species. They are generalists that can survive in a variety of conditions, from the frigid forests of the Russian Far East to the hot tropical forest in southern Asia. All they need to thrive is some decent forest — it doesn’t have to be pristine old-growth —and protection from people. At the site-level — say a national park — tiger conservation involves patrolling to catch poachers and stop habitat degradation while working with local communities to improve their lives in ways that have a reduced impact on tigers and their habitat.
At larger scales, we need to ensure protected areas remain connected by tiger habitat, which is more complex and means planning and managing infrastructure development, agriculture and logging, in conjunction with local communities. These are usually the areas where tigers and people overlap, so we also need to manage human-tiger conflict to minimize and mitigate attacks on livestock and even people.
The Tiger King series shed light on the commercial exploitation of captive-bred tigers in the U.S. — as have several other investigative news pieces in recent months. What’s going on?
When most people think of breeding tigers for profit, they think of Asia’s tiger farms, where there are thousands of tigers in captivity. However, many countries breed and exhibit tigers for commercial purposes, either legally, or by skirting the law. In the U.S., there are an estimated 5,000-10,000 tigers in captivity, not including those in accredited zoos. These tigers are bred for profit — not for conservation or education. In the U.S., 95% of captive tigers are privately owned. They are bred and kept primarily to entertain tourists who pay to pet and feed tiger cubs and have their photos taken with them.
“Roadside zoos” that exhibit wild cats often market themselves as having a conservation mission. Can tigers bred at these facilities ever be released in the wild?
Commercially captive-bred tigers cannot be used to restore dwindling wild tiger populations. Genetically, they are unfit for re-introduction; they are hybrids of the five extant wild tiger subspecies, or even bred with other cat species, like lions, and often have genetic defects. Further, generations in captivity and handling by people means they would be unlikely to survive in the wild. Most tigers in captivity are bred for human use and entertainment.
The concerns about the welfare of tigers in these places are pretty obvious. But do roadside zoos have any negative impacts on wild tigers?
The biggest threat from these backyard operations is the role they play in deflecting attention and dollars away from the plight of wild tigers and legitimate efforts to save them. Roadside zoo owners often engage in “greenwashing” to protect their image and attract visitors. They may make small donations to conservation organizations, or say they do, but there is no evidence that any of these operations are substantively funding wild tiger conservation. Also, the captive tiger cubs that age out of “pay-to-play” petting, or get too big for an owner to handle, have to go somewhere. This has created a need for big cat sanctuaries in the U.S. that raise funds from the public to house and maintain these cats for the rest of their lives. Meanwhile, funding for wild tiger conservation has been harder and harder to come by in recent years even as some populations in Southeast Asia teeter on the brink of extinction. It’s a cruel irony that it will cost more to take care of America’s glut of unwanted tigers than it would to secure a future for tigers in the wild.
Commercial breeding advocates make a case that increasing the supply of captive-bred tigers in the marketplace takes the pressure off of wild populations. Is that true?
Any trade in tiger parts, whether legal or illegal, perpetuates demand for tiger products and keeps poachers in business. Despite the increase in Asia’s commercial captive breeding facilities in the past decade and the surplus of captive-bred tigers in the marketplace, poaching of wild tigers continues unabated. There is no evidence that farming tigers takes the pressure off of wild populations and it may actually be hurting them.
Does Panthera endorse big cat sanctuaries?
We would like to see a day when there is no need for big cat sanctuaries in the United States, but for now, rescue centers and sanctuaries are a necessary consequence of our captive tiger trade. They provide a home for unwanted cats, for example, when someone buys a tiger cub as a pet but abandons it when it gets too big. These operations should be certified by the Global Federation of Animal Sanctuaries, which requires, among other things, that the organization is non-profit, does not buy or sell cats, does not allow public contact with cats, and adheres to strict animal welfare standards.
Can captive breeding of big cats be beneficial to conservation?
Zoos accredited by the Association for Zoos and Aquariums (AZA) contribute to the conservation of wild species through the Species Survival Program (SSP). The SSP requires all AZA zoos to carefully manage the breeding of captive tigers to maintain pure genetic strains of subspecies and to minimize inbreeding so that if ever needed, animals from these zoos would be genetically suitable for release into the wild. These zoos do not breed for profit and do not allow public contact with tigers. They also contribute to conservation through funding, education and on-the-ground work in tiger range.
Does Panthera support the Big Cat Public Safety Act?
The Big Cat Public Safety Act is a step in the right direction to greatly limit who can own a big cat in the U.S. and under what circumstances. Enacting a federal law to restrict the unchecked breeding and exploitation of big cats is long overdue in this country. If rigorously enforced, the Big Cat Public Safety Act will not only protect captive-bred cats and people but will help to dismantle an industry with insidious implications for wild tigers by shrinking the availability of tiger parts for the global illegal wildlife trade.
We believe the law could be strengthened by requiring that existing privately held cats are spayed and neutered, and requiring that all animals are chipped and their fate tracked, to help ensure they are not traded illegally.
The Effects of the Extinction of an Organism in a Desert Ecosystem Food Chain
The desert is a harsh, dry environment, but plants and animals who have adapted to those conditions thrive in these ecosystems. From eagles to ants, there are a diverse range of plants and animals that live and interact with one another in deserts around the world. Like all ecosystems, the web of species interactions can be fragile, and species extinction can have a large effect. The identity of the organism that is lost and its role in the ecosystem determines how the food chain is affected.
Desert Food Chains
All ecosystems are composed of species that perform different roles in the food chain. In the desert, shrubs and cacti are the primary producers and form the base of the food chain. Next, there are small herbivores that eat the plants such as:
Above this trophic level there are mesopredators like foxes, snakes, and lizards that prey upon the small consumers. Finally, at the top of the food chain, animals like cougars and eagles will prey on all of the species below them. The role of the species that goes extinct plays a big role in how the food chain will be affected.
Not all extinctions have big impacts on ecosystems. Sometimes there are a lot of different species that essentially perform the same job or function in an ecosystem. If one of these species goes extinct, the others will increase in number and perform the same job. Such a “replaceable” species is called functionally redundant. Since deserts are harsh environments, species are more similar to one another because they need similar adaptations to survive. For example, Guofang Liu at the Chinese Academy of Science found that plants in the desert steppe of Mongolia have less functional diversity than plants in the meadow and typical Mongolian. This may indicate that plant extinctions in the desert may not have as big an impact as extinctions in other ecosystems.
Sometimes extinction can have a disproportionately large impact on an ecosystem. Such important species are called keystone species. Often keystone species are predators that maintain the stability of the entire ecosystem. The most well-known example is a species of seastar — Pisaster ochraceus — on the Washington Coast. When it’s removed from the rocky intertidal, lots of other species go extinct as well. Top predators in the desert such as cougar and eagles are similarly important. Another keystone species in the American desert are hummingbirds. These are important pollinators of desert cacti that support a range of other species. When the hummingbirds are lost many desert plants and the species that depend on them disappear as well.
Domino Extinctions and Other Effects
Sometimes species are closely linked to another species. When one goes, the other one that depended on it goes as well just like dominoes knocking each other over. A great example in the desert is the relationship between prairie dogs and black footed ferrets. Black footed ferrets depend on prairie dogs for food. When prairie dogs were driven to low numbers due to poisoning, the black footed ferret went extinct in most places. Species extinctions can also alter the structure of desert food. For example, if large kangaroo rats go extinct in desert grasslands, the grassland turns into shrub land because the important seed predation job the kangaroo rats performed has been lost.
Effect of multiple disturbances on food web vulnerability to biodiversity loss in detritus-based systems
Global biodiversity is affected by human pressure and climate change, and the present rate of biodiversity loss is probably higher than ever before. Community composition is also changing, and interspecific interactions are under severe pressure. The extinction of one species within a food web can result in further secondary extinctions, due to bottom-up effects that can be even more intense and less predictable than the direct effects of disturbance, undermining our capacity for ecosystem management and conservation. Here we investigated a metric for assessing the structural stability of food webs in the face of species loss, referred to as “Resistance”, based on two fundamental web properties: (1) the proportion of key species in the web, a “key” species being one whose deletion leads to at least one secondary extinction, and (2) the mean number of secondary extinctions observed per key species deletion. We compared web Resistance with web Robustness based on 12 detritus-based riverine food webs under four species extinction scenarios on various temporal and spatial scales. We investigated the effect of multiple disturbances (extreme flood and river basin urbanization) on community vulnerability to biodiversity loss, assessing the behavior of Robustness and Resistance under the applied species extinction scenarios and testing their dependence on web topology. We estimated the contribution of the rarest and the most dominant species, and that of the most and least connected species, to web Resistance.
Urbanization negatively affected community vulnerability to biodiversity loss. Only food web Resistance showed a significant flood effect and interaction between flood and urbanization. The most connected species contributed the most to food web resistance, whereas the rarest and the most abundant species had a similar, intermediate structural importance. Both food web Resistance and the role of selected key species varied across web description scales. Food web Resistance values were coherent across species extinction scenarios, demonstrating the suitability of the proposed approach for quantifying community vulnerability to species loss and the importance of considering food webs in monitoring and impact assessment programs. The approach is thus seen to be a promising research pathway supporting ecosystem management.