List of Keystone / Umbrella Species
Given that there are many historical definitions of the keystone species concept, and without a consensus on its exact definition, a list of examples best illustrates the concept of keystone species. Opposite of keystone species: Destructive non-native species.
Keystone / Apex Carnivory Predators
Grizzly bears keep down the numbers of several species, like moose and elk. They also carry and deposit seeds throughout the ecosystem. Bears that eat salmon will leave their dropping and the partially eaten remains that provide nutrients such as sulfur, nitrogen and carbon to the soil.
Mountain Lions are predator keystone and umbrella species. Deer, rabbits, and bird species in the ecosystem are at least partly controlled by the presence of the mountain lion. Their feeding behavior, or where they choose to make their nests and burrows, is largely a reaction to the mountain lion’s activity.  They cover large areas and influence many species. Their prey will alter where they eat and live because of the mountain lion. Scavengers are also affected by the mountain lion’s activity.
Jaguars have a very diverse diet of about 87 different species, which contributes to their importance by keeping the numbers of these species in balance.
Komodo Dragon apex predator
Sharks, particularly Tiger Sharks, eat practically anything. This helps control populations of sea turtles and dugongs who may cause overgrazing of the sea grass in Western Australia. Since sea grass is where fish lay their eggs, overgrazing would lead to fewer fish.
American alligators use their tails to make burrows to stay warm and when they move on, these burrows fill with water which is used by other species. Alligators are also predators, keeping the numbers of other species in check.
Gray Wolves (Canis lupus) are a top predator important in many habitats. Wolves keep elk and deer populations in check. Too many deer will eat small trees, which leads to fewer trees. In turn, there would be fewer birds and beavers and the whole ecosystem would change. Too many elk would overgraze plants.
Coyotes have a regulatory effect on smaller predator (mesopredator) populations, which allows prey of the smaller predator species to survive.
Eastern Indigo Snakes - endangered - eats everything
King snakes eat venomous snakes
Leather back Sea Turtles - eat jellyfish
Sea otters
Enhydra lutris)
Ochre Sea Stars
Pisaster ochraceus)
Bats keep the insect population in check, particularly mosquitoes.
Agelaia vicina Wasps have an unparalleled nest size, colony size, and high rate of brood production. The diversity of their prey and the quantity necessary to sustain their high rate of growth have a direct impact on local neighboring species.
Fire Ants, in terrestrial environments, suppress the numbers of individuals and species of arthropods that could be harmful to agriculture.
Keystone Herbivory Predators
native to African grasslands (savannas)
. Without the presence of elephants, grasslands would probably develop into forests. Elephants graze on trees such as acacias, above, preventing them from growing to maturity. By eating small trees, elephants preserve the grasslands, because the grasses need plenty of sun to survive. If they were not there, the savanna would convert to a forest or scrublands.
Snow geese
in salt marshes
prevent other harmful species from taking over. When the geese graze, it leaves open areas for other varieties of plants to take root, thus adding to the diversity of the habitat.
Weevils (Euhrychiopsis lecontei) are insects that forage on the nuisance Eurasian watermilfoil.
Keystone Mutualists
in the
region of
a period of each year when
Banksia prionotes
(acorn banksia) is the sole source of
of numerous plant species.
spread the seeds of many different trees, and some will not grow unless they have been through a cassowary.
in the Sonoran Desert
pollinate many varieties of native cactus and other plants. In areas of the Sonoran Desert with few hummingbirds, invasive species such as buffelgrass have taken over the ecosystem. Pollination is the reason hummingbirds are a keystone species mutualist. In places where the numbers of hummingbirds are low, other species of plants will take over the ecosystem.
pollinate plants, contributing to the plant's survival. The plants are shelter for insects, which are then eaten by other species, like birds.
Pacific Salmon
die after spawning and this brings important nutrients to the place where they were born. Their death provides food for many species in the area.
Oysters filter water and provide food for many other species.
Plankton create oxygen and provide food for many species.
Spruce Budworms
are moths that live in conifer forests. As the population of budworms increases, more small animals and birds move into the area to eat the larvae. This will cause some trees to die, but they will be replaced by younger trees, and the cycle will begin again.
Keystone Hosts
Red mangrove
trees grow along the shoreline in the tropics and its roots protect the soil from erosion. The roots also offer protection to small animals, including reef fish.
Sugar maples
of the hardwood forests bring water from lower levels in the ground that helps other plants. It is also home to many insects, birds, and small animals.
Saguaro cactus
Carnegiea gigantea
in desert environments
provide habitat for a variety of other species.
Palm Trees
in tropical forests provide habitat for a variety of other species.
Fig Trees in tropical forests provide habitat for a variety of other species.
Ivory tree coral
: 300 invertebrate species call this coral home. It is here that fish live, breed and become food for larger fish.
Oaks provide habitats for many species in certain areas.
Keystone Modifiers
Gopher tortoises make large burrows which are used by around 400 species. The most essential species in their range (Southeastern U.S.).
North American Beavers (Casor candensis) are considered habitat engineers because they change the environment by building dams. This dam building provides still water in which many species flourish.
Prairie dogs
Parrotfish, on the Great Barrier Reef, Australia, is the sole species, within thousands of species of reef fish that consistently scrapes and cleans the coral on the reef. Without these animals, the Great Barrier Reef would be under severe strain.
Oysters filter water (also keystone prey).
Keystone Prey
California mussels (Mytilus californianus)Oysters (also keystone modifier / filter)
Kemp's Ridley Sea Turtle