A mesopredator is a

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

that occupies a mid-ranking

trophic level The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the ...

in a

food web A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Position in the food web, or trophic level, is used in ecology to broadly classify organisms as autotrophs or he ...

. There is no standard definition of a mesopredator, but mesopredators are usually medium-sized

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

animals, such as

raccoons The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

foxes Foxes are small-to-medium-sized omnivorous mammals belonging to several genera of the family Canidae. They have a flattened skull; upright, triangular ears; a pointed, slightly upturned snout; and a long, bushy tail ("brush"). Twelve species ...

, or

coyotes The coyote (''Canis latrans''), also known as the American jackal, prairie wolf, or brush wolf, is a species of canine native to North America. It is smaller than its close relative, the gray wolf, and slightly smaller than the closely relat ...

. They are often defined by contrast from

apex predator An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...

s or prey in a particular food web. Mesopredators typically prey on smaller animals. Mesopredators vary across different

ecosystems An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...

. Sometimes, the same

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

is a mesopredator in one ecosystem and an apex predator in another ecosystem, depending on the composition of that ecosystem. When new species are introduced into an ecosystem, the role of the mesopredator often changes; this can also happen if species are removed. The American Institute of Biological Sciences states that due to the fact that mesopredators are smaller than large carnivores, they are more abundant, and therefore have greater diversity of mesopredator species. Due to their smaller size, mesopredators play a part in the ecosystem of dispersing seeds in open spaces, as well as driving community structure. Mesopredators are also very diverse in comparison to larger carnivores in their behaviour and ecology, from being reclusive to highly social. Their diversity and small size allows them to thrive in a range of habitats than larger carnivores are able to. The population of these smaller carnivores also increases when the presence of a larger carnivore decline. This is known as the 'mesocarnivore release.' According to the National Park Service, "Mesocarnivore release is defined as the expansion in range and/or abundance of a smaller predator following the reduction or removal of a larger predator." One impact of this is that these mesopredators can act as scavengers cleaning up dead animal carcasses discarded by humans in urban areas. Mesopredators' habitat have shifted and changed, due to urbanisation, leading to habitat fragmentation and disturbance, resulting in habitat loss for animals.

Mesopredator release effect

When

populations Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and pl ...

of an apex predator decrease, populations of mesopredators in the area often increase due to decreased competition and conflict with the apex predator. This is known as the

mesopredator release effect The mesopredator release hypothesis is an ecological theory used to describe the interrelated population dynamics between apex predators and mesopredators within an ecosystem, such that a collapsing population of the former results in dramatically ...

, which refers to the release of mesopredators from the

trophic cascade Trophic cascades are powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed. For example, a top-down cascade will occur if predators are effective enough in predation to redu ...

. These mesopredator outbreaks can lead to declining prey populations, destabilized

ecological communities In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis, biotic community, biological community, ecological community ...

, reduced biodiversity, and can even drive local

extinctions Extinction is the termination of an organism by the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. As a species' potential range may be ...

. Typically, mesopredators are in competition with apex predators for food and other resources. Apex predators reduce mesopredator populations and change mesopredator behaviors and habitat choices by preying on and intimidating mesopredators. When apex predator populations decline, mesopredators can access hunting and den areas once controlled by the apex predators, essentially assuming the role of an apex predator. However, mesopredators often occupy different

ecological niches In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for e ...

than the former apex predator and will have different effects on the structure and stability of the ecosystem. Mesopredator outbreaks are becoming more common in

fragmented habitat Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological proces ...

s, which are areas where a species' preferred environment is broken up by obstacles. Fragmented habitats can be caused by geological or human activity, and particularly affect larger animals that roam and hunt across large territories, such as apex predators. Fragmented habitats can drive these species to leave and find more suitable habitats. Additionally, in many fragmented habitats, apex predators have more encounters with humans, leaving them susceptible to harmful or deadly conflicts, sometimes resulting in eradication of the apex predator population entirely. Human development also promotes mesopredator outbreaks through increasing access to resources such as pet food, trash, and crops. The mesopredator release effect is not entirely understood. Most research has been conducted on

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

species, with limited studies on non-mammal animal species. Additionally, it is not well understood how these dynamics may play out in ecosystems with many mesopredator and apex predator species.

References

{{Reflist Ecology

Mesopredator release effect

See also

References