In Yellowstone National Park, gray wolves act as keystone predators by controlling elk and deer populations, which had previously overgrazed and disrupted river systems that supported many more mammal, fish, and avian species.

Although ecologists have struggled to identify a species as a keystone—one of outsized importance to its ecosystem—an analysis of 50 years of data and 157 studies identified 230 such species.

Keystone species with average lifespans exceeding a century, oak trees support more organisms than any other North American tree genus by providing ecosystems with pollen, shelter, and nutrient-rich acorns.

Possessing trunks that contain about 40,000 individual muscles, African elephants act as keystone species by trampling and clearing trees, making pathways in forests, digging water holes, and spreading seeds.

Able to hold their breath for up to 15 minutes, beavers are considered keystone species via their construction of dams and formation of wetlands, which serve as homes and food sources for fish, birds, insects, and other animals.

Contributing to one in every three bites of food consumed by humans, bees are a keystone species because of their essential role as pollinators of about 80% of all flowering plants worldwide.

Bees are crucial for pollination and food security

When animals and insects pick up the pollen of flowers and spread it, they allow plants, including many food crops, to reproduce. The most common pollinator is the bee, but bees are at risk from pollution and pesticides.

The concept of keystone species—organisms that have disproportionately large impacts on their ecosystems—was discovered through studies of purple sea stars in Pacific tidepools.

While invasive species typically harm ecosystems by outcompeting native organisms for resources, some provide unexpected benefits, including new shelters, nesting habitats, and reduced environmental heat stress.

By targeting a diverse range of sick and injured marine life, sharks—a type of predatory keystone species—help keep ocean gene pools healthy and promote biodiversity by keeping prey species in check.

Over 1 million fish, marine mammals, and invertebrate species depend on coral reefs for habitats, camouflage, and food.

Desert wildlife: diverse, threatened, and misunderstood

This article sheds light on the surprisingly diverse wildlife that thrive in deserts, while also highlighting the gaps in human understanding of these ecosystems. Deserts are home to one-quarter of terrestrial vertebrate species—three percent of...

During a trophic cascade, the disappearance of a keystone species, which plays an indispensable role in ecosystems, triggers a domino effect within food webs that disrupts the populations of many more species.

As part of the up to 15 pounds of seafood they consume daily, sea otters eat urchins that feed on kelp forests—sources of shelter and food to over 800 species—thereby making the marine mammal a keystone species.

Some mosquitoes are key pollinators—and eat disease-carrying mosquitoes.

About one-third of the world's food supply depends on pollinators like bees, butterflies, and bats to transfer pollen between flowers, which use bright colors, scents, and nectar to attract them.

Some invasive species can provide benefits to ecosystems over time

In the 1990s, round gobies were introduced into the Great Lakes, rapidly spreading and competing with local sculpin and logperch. However, Lake Erie watersnakes, which were on the endangered species list, shifted their diet to be almost entirely made up of the plentiful round gobies, contributing to their loss of endangered status in 2011.

Research suggests ants are the most abundant insect on the planet, with an estimated 2.5 million of them for every human on Earth.

Mammals thrived under the feet of dinosaurs

An explosion of fossil finds reveals that ancient mammals evolved a wide variety of adaptations allowing them to exploit the skies, rivers and underground lairs.

Adding garden beds with blooming plants to an existing lawn can support bees

Blooming wildflowers, shrubs, and trees can provide the nectar and pollen these pollinators need but do not get from grass. Other tips include leaving patches of bare soil for ground-nesting bees to lay their eggs and filling birdbaths with large pebbles for them to land and drink from safely.

Farm animals help maintain the grounds at Chicago's O'Hare International Airport

Since 2013, a herd of goats, sheep, and a donkey have grazed on the scrub vegetation at the airport. In the process, they also help keep out animals that can be dangerous for pilots, like coyotes.

Across the animal kingdom, parenting can include adults carrying their young, providing their bodies for sustenance, searching for food and shelter for their children, and separating siblings who may eat one another.

Some animals, including certain tropical ants, have little or no microbial populations in their gut, upending the idea that all animals rely on this ecosystem to help maintain their health and proper functioning.

Appropriate timing of land management techniques can help support pollinators

The mowing, grazing, and burning practices used to maintain land should be tailored to the life cycles and needs of native pollinators, particularly those of rare or endangered species. For example, mowing is recommended in the fall or winter when flowers are not in bloom.

Fig trees are considered keystone species because they provide year-round habitat and fruit, which are eaten by an estimated 1,300 species of birds and mammals worldwide.

Explore guides on pollinator-friendly plants native to where you live

Pollinators have co-evolved alongside specific plants from their natural habitat and see their populations increase in environments with these native flora. This collection offers recommendations for regional plants that can provide nectar and pollen, serve as host plants for caterpillars, and offer nest sites for specialist bees.

Some dinosaurs evolved night vision and acute hearing for nocturnal hunting

Paleontologists analyzed the fossilized eye and ear structures of 16 theropods, finding that some had owl-like hearing and huge pupils. These characteristics are consistent with modern-day nocturnal species, including nightjars and geckos.

Benign species can become invasive if introduced into predator-free habitats

Most ecosystems contain organisms that, over many generations, have evolved into a stable balance with one another and their surroundings. In a new environment, a species may no longer be restricted by the limiting factors it is used to, and the native organisms in the area may not adapt quickly enough to the invader to establish a new balance.

The jaguar is the largest feline in the Americas and serves as a keystone species by acting as an apex predator with a diverse diet across multiple environments, thereby regulating the populations of dozens of species.

Some animals possess sensitive hearing to help pinpoint prey and map the world

Bats and dolphins produce sound to reflect off surfaces and create a mental image of their surroundings. Owls' faces are dish-shaped to help funnel sounds to their ears, including that of mice moving along leaves or snow. Pinnipeds, such as seals and walruses, hear in both air and water.

Over 1,500 insect species pollinate plants in the UK

These insects—including bumblebees, moths, butterflies, and beetles—play a crucial role in the reproduction of flowering plants, also known as angiosperms. They do so by transferring pollen from the male reproductive organ—the anther—to the female one—the stigma—which enables the plant to produce fruit.

Coevolution of pollinators and flowering plants diversified both

The first pollinators were beetles, which consumed pollen before flowering plants existed. Over time, plants evolved to attract more insects and improve the uptake of pollen, while insects adapted their biology to enhance the capture of pollen, such as developing specialized mouthparts.

Biosphere 2 revealed limitations in maintaining wildlife in unfamiliar environments

Trees appeared to become weak and more prone to breaking because a lack of wind caused them to no longer need to develop stress wood. The extinction of pollinators—potentially due to an explosion in the population of longhorn crazy ants—was also unexpected.

Microbial research suggests shifts in diverse populations may help an invasive species establish itself

In 1958, English ecologist Charles Elton suggested that diverse ecosystems should be more resistant to invasive species because gaining a foothold would be more challenging when resources are more thinly spread. However, in lab-grown microbial ecosystems with greater biodiversity, population volatility opened more ecological roles that invasive species could easily fill.

Human beekeeping has been traced back to 7000 BCE

Eighty-seven of the world's leading crops rely on pollination in some way, including 43 that are highly dependent or entirely reliant on it. Without pollinators, key foods such as apples, avocados, and almonds would likely become extinct, pushing entire ecosystems into collapse.

Explore a collection of galleries of pollinators found in national parks

Many of the photographs were taken during pollinator inventories in national parks across the US. Although these inventories often focus on bees and butterflies, the collection also features beetles, moths, spiders, and birds that transfer pollen as they move from bloom to bloom.

Invasive species may harm new ecosystems via the spread of disease

Besides damaging native species through direct interactions such as competition for resources and predation, invasive species may come from environments with greater biodiversity than the new environment. This makes them more likely to carry pathogens unfamiliar to native species, increasing the risk of biodiversity loss.