Why preserve predatory species

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You cannot download interactives. Extinction is the complete disappearance of a species from Earth. Species go extinct every year, but historically the average rate of extinction has been very slow with a few exceptions. The fossil record reveals five uniquely large mass extinction events during which significant events such as asteroid strikes and volcanic eruptions caused widespread extinctions over relatively short periods of time.

Some scientists think we might have entered our sixth mass extinction event driven largely by human activity. Our planet is dependent on an interconnected system. If we lose one species, how does that impact the whole system?

What if we lose hundreds? Help your students understand the gravity of extinction with these classroom resources. Marine ecosystems contain a diverse array of living organisms and abiotic processes. From massive marine mammals like whales to the tiny krill that form the bottom of the food chain, all life in the ocean is interconnected. While the ocean seems vast and unending, it is, in fact, finite; as the climate continues to change, we are learning more about those limits.

Explore these resources to teach students about marine organisms, their relationship with one another, and with their environment. A biotic factor is a living organism that shapes its environment.

In a freshwater ecosystem, examples might include aquatic plants, fish, amphibians, and algae. Biotic and abiotic factors work together to create a unique ecosystem. Learn more about biotic factors with this curated resource collection. Whether a description of a keystone species or the impact of the Pacific garbage patch, these articles provide insight into a breadth of important issues facing our world today, including the environment, civic engagement, and history.

The species population size is limited by environmental factors like adequate food, shelter, water, and mates. If these needs are not met, the population will decrease until the resource rebounds. Explore carrying capacity with these curated classroom resources. Every ecosystem has certain species that are critical to the survival of the other species in the system. The keystone species could be a huge predator or an unassuming plant, but without them the ecosystem may not survive.

Biodiversity refers to the variety of living species on Earth, including plants, animals, bacteria, and fungi. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.

Skip to content. Twitter Facebook Pinterest Google Classroom. Article Vocabulary. The ochre sea star Pisaster ochraceus is the keystone of keystone species. Photograph by Paul Nicklen, National Geographic. Nutrient Vectors. Grizzly bears, for instance, prey on salmon.

They can deposit salmon carcasses miles from rivers and streams. Salmon carcasses decompose and fertilize the soil with nutrients that may not be available from local terrestrial ecosystems. Keystone Prey. By the s, a previously healthy breeding population of wolves was extinct in Montana. While the decimation of any species is tragic, the loss of top predators can have an even more profound effect on an ecosystem.

This statement might sound like a paradox, as predators eat other animals, thereby seeming to cause death, not life. However, by keeping other populations in check, predators ensure that a multitude of species occupying a variety of environmental niches can survive and thrive. Science Illustrated recently published a blog post about the impact of predator disappearance.

But just how do predators help maintain a healthy balance in nature? Without predators to regulate prey populations, these species will reproduce beyond the carrying capacity of their environments, decimating the populations of smaller animals, plants, and coral reefs.

As these species decline, additional organisms that rely on their presence will also decline, resulting in a domino effect that can ultimately push populations and habitats beyond the point of recovery. In the wake of Shark Week, awareness about the current status of shark conservation is high. The shark fin business alone is responsible for up to 73 million shark deaths each year.

The disappearance of large sharks has resulted in the increase of 12 out of 14 small shark and ray species, which are usually preyed upon by larger sharks. These smaller organisms in turn are wreaking havoc on mollusk populations, as, without predators to regulate them, their populations are growing at a faster rate than the mollusk community can support.

At these numbers, the rays can consume upwards of , tonnes of Atlantic Bay Scallops in the Chesapeake Bay region in their first days each year in the region. The decline of large sharks in more southern, tropical waters has led to an increase of species that consume reef-building corals, thus threatening the health of coral reefs. Ecosystem disruption is, of course, not limited to the disappearance of top predators.

The loss of any species has an impact on healthy habitat function, including the oft-despised scavengers. Last year, we wrote about the fate of the vulture in South Asia. Like sharks and raptors, vulture populations have plummeted as a result of poisoning which primarily contributed to the loss of over 14 million birds. As outlined earlier, the status of wolf populations in the United States was jeopardized in the early twentieth century. As wolves disappeared, elk populations, along with other grazers, increased unchecked.

Aspen, cottonwood, and willow tree stability fell, affecting the smaller mammals and birds that relied on them. The carcasses left behind by wolves were also of critical importance to scavenger species, like coyotes, ravens, and eagles, particularly during the winter.

Perturbations to trophic interactions and the stability of complex food webs. PNAS , August 11, , vol. Large predators and trophic cascades in terrestrial ecosystems of the western United States. Biological Conservation Effects of predator functional diversity on grassland ecosystem function. Ecology , 90 9 , , pp. Does interference competition with wolves limit the distribution and abundance of coyotes? Journal of Animal Ecology 76, — Gese, J. Ecology , 89 3 , , pp. Slater, C. The Condor — Caro, D.

Brown, B. Clucas, J. Hunter, J. Ketchum, K. McHugh, F. Conservation Biology Vol. Linking a cougar decline, trophic cascade, and catastrophic regime shift in Zion National Park. This vegetation supports other herbivores like antelopes, wildebeests, and zebras; it also provides warm, dry soil for smaller animals like mice and shrews to burrow into.

In turn, these prey species feed carnivores such as lions, hyenas, and cheetahs. This vital species is under attack from poachers and trophy hunters and at risk of extinction.

Residing in the grasslands of central and western North America, prairie dogs are a keystone species that supports some plus other species. In addition to serving as a food source for coyotes, eagles, the endangered black-footed ferret , and other animals, they are ecosystem engineers, maintaining the health of arid grasslands by churning, aerating, and fertilizing soil as they create vast and intricate underground colonies.

Their digging allows an array of vegetation to thrive, which in turn supports a greater number of elk, bison, and other grazers. And their burrows provide shelter for animals like rattlesnakes, burrowing owls, and jackrabbits. When prairie dogs disappear from their native grasslands habitat, woody plants can take over , fundamentally altering the prairie ecosystem.

Not only do they pollinate fruits, vegetables, and other crops that provide humans with everything from food to clothing to fuel , but they also help produce the seeds, nuts, berries, and fruit that countless other species in ecosystems around the world survive on. Without bees, there would be a bottom-up cascade of consequences throughout the food chain. Despite this, bees like the endangered rusty patched bumblebee have failed to receive crucial protections in the United States.

Left: Krill. At the top of the food chain, sharks are keystone predators that have a top-down impact on marine ecosystems worldwide. By preying on the sickest, weakest, and slowest animals, they control the spread of disease and keep prey populations in check.

They impact local habitat, too: By hunting predatory fish like grouper in Caribbean reef ecosystems, for example, sharks allow populations of herbivorous fish farther down the food chain to thrive, and these fish, in turn, graze on algae that otherwise degrade coral reef.

Some types of corals are considered keystone species as well. One example is ivory tree coral , which is found in the waters off the southeastern United States, the Gulf of Mexico, and the Caribbean and provides valuable habitat for more than invertebrates. Other oceanic keystone species include krill a vital food source for myriad whales, seals, and seabirds in Antarctica and mangrove-dwelling crabs which manage leaf litter and create burrows that improve underwater soil health.

Native to the Sonoran Desert of the southwestern United States and northwestern Mexico, the saguaro cactus is a keystone species that provides critical nesting spots for birds like red-tailed hawks and woodpeckers the latter of which peck new nest holes each year, leaving old holes for other birds. These cacti serve as an important source of sustenance, too. Their blooming flowers feed bats, birds, and bees, while their fruit, which ripens when the desert is at its driest, is often the sole wet food source for myriad mammals, insects, and other species.

Other desert keystone species include the desert tortoise of the Mojave which digs burrows that other animals rely on for protection from predators and the desert heat and the Australian dingo, which preys on both predators in the middle of the food chain, like invasive red foxes and feral cats, as well as a wide range of herbivores e.

In the Canadian boreal , the snowshoe hare is an example of a keystone prey species, serving as food for the threatened Canada lynx which relies on snowshoe hares for more than 75 percent of its winter diet , and other predators. In the boreal, keystone species also include trees like aspen and willow these provide critical habitat for myriad organisms like lichens, fungi, insects, and birds and plants like wild red raspberries, which are a critical food resource for animals from bees to bears.