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Rewilding glossary

From apex predator to zoopolis, we demystify the A — Z of rewilding for you.

Long eared owl
 © James Warwick / Wildscreen


Active rewilding

Restoration of ecosystems and ecological processes through active human intervention, often by reintroducing missing species that provide ecological functions or introducing functional equivalents, and/​or removing historical modifications such as drainage ditches.


The process of establishing trees or woodland in an area where there was no previous tree cover. See reforestation and natural regeneration.

Agriculture, extensive

An agricultural system that uses low inputs (of labor, fertilisers, capital etc) relative to the land area being farmed, which is usually large and not highly productive.

Agriculture, intensive

An agricultural system with high levels of input and output per unit area.

Agri-environment schemes

(Government) funding for farmers and landowners to incentivise land management that supports biodiversity, enhances the landscape, and improves the quality of water, air and soil.


An ecological approach to agriculture that views agricultural areas as ecosystems in their own right and is concerned with the ecological impact of agricultural practices.

Ancient Semi-natural Woodland (ASNW)

The closest we have in the UK to natural/​wild woodland; it will have been managed or cleared at some point, but has been wooded since reliable records began in 1600AD (1750AD in Scotland).


The era of geological time during which human activity is considered to be the dominant influence on the environment, climate, and ecology of the earth. The Anthropocene is most commonly taken to start at the Industrial Revolution and continue to present day, but is sometimes considered to include much or all of the Holocene.

Apex predator

A predator that occupies the highest trophic levels, i.e. at the top of a food chain without natural predators of its own. Apex predators often have large influences in an ecosystem (see trophic cascade) and are often keystone species. Also known as a top predator.

Assisted colonisation

The translocation of species beyond their native range.


Bos primigenius, an extinct species of large wild cattle from which domestic cattle are derived. Aurochs once inhabited Asia, Europe, and North Africa.


Back breeding

A structured breeding program to restore wild traits to domesticated species. A key example is a controversial effort by the Heck brothers in 1920s-30s Nazi Germany to create a breed of cattle with the traits of the extinct aurochs — known as Heck cattle. 

Baseline survey

An ecological survey at the beginning of a project to collect information on the baseline status of species and ecosystem functioning of an area before any interventions are made, to allow for comparison over time and after intervention (or removal of management).

Basic Payment Scheme (BPS)

A rural payment scheme for landowners and farmers, consisting of a flat rate per unit area with varying value depending on factors such as crops planted, habitat types represented and location. 


Short for biological diversity, this is the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.” (Convention of Biological Diversity) Often used as a catch-all term for all living species. 

Bottom-up processes

Processes driven by resources (e.g. space and nutrients) and lower trophic forms, e.g. producers and primary consumers, influence those on higher trophic levels. See trophic level.


An animal that eats leaves, soft shoots and fruits, usually of trees and woody species. See also: grazer

Buffer area/​zone

An area surrounding a core wilderness area where some human activity is permitted but that still provides some habitat for wildlife, allowing for gradual transition between wild nature and more intensive or industrial human activity. 


Carrying capacity

The number of organisms that an ecosystem can sustainably support, beyond which the environment becomes degraded, resources deplete and organisms may die off. An ecosystem’s carrying capacity for any particular species may be influenced by many factors, for example food availability, water availability, territory or mates.

Common Agricultural Policy (CAP)

EU policy to provide financial support to farmers in member states. Its aim is to increase agricultural productivity by promoting technical progress and ensuring the optimum use of the factors of production, in particular labour, and ensure a fair standard of living for farmers. It is widely criticised for leading to overproduction, forming large amounts of surplus produce which are either destroyed or dumped on developing nations, undermining the livelihoods of farmers there.


How connected habitats are. Connectivity is important because isolated fragments of habitat are more vulnerable to disturbance, genetic bottlenecks and other risks that may cause species to decline and ultimately fail.


(Also known as heterotrophs) Organisms which cannot produce their own food, and so must consume other organisms in order to acquire nutrition. See also producer, decomposer.

Core wilderness area

A protected area where many/​all human activities are restricted or prevented to preserve wildlife, habitat and wilderness. Core areas tend to be large, with management/​intervention absent or minimal. They may be surrounded by buffer areas and connected by wildlife/​habitat corridors.

Corridors, habitat/​wildlife

Areas of conserved, protected or high quality habitat that link larger wildlife areas together, allowing for the movement of wildlife between such areas and preventing fragmentation and isolation. See connectivity.

Climax (vegetation) community

The vegetation community of the final stage of ecological succession, usually dominated by a small number of prominent species. It will usually remain relatively stable until destroyed by an event such as fire or human interference.



(Also known as detritivores) Organisms which consume dead plant and animal matter, converting it into energy and nutrients that plants can use for growth. E.g. fungi, bacteria, earthworms and flies. An important part of a functioning ecosystem. (Biology Dictionary) See also producers and consumers.


Also called resurrection biology, the process of resurrecting species that have gone extinct e.g. woolly mammoth.

Domestic proxy

A domesticated breed of animal used to replicate services provided by a wild animal, e.g. Tamworth pigs used to fulfil the ecological role of wild boar.

Driver (of change)

Any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver (e.g. herbivory, predation, climate change, disease) unequivocally influences ecosystem processes. An indirect driver (e.g. policy, economics, scientific/​technological advances, cultural shifts) operates more diffusely, by altering one or more direct drivers.



A process whereby activities carried out in the name of conservation lead to an infringement upon the rights, cultures or traditions of a group of (usually indigenous) people, mainly in the context of international relations but also emerging in discourses around rewilding and local communities.

Ecological rewilding

Another term for passive rewilding.

Ecological restoration

See restoration.

Ecological remediation

The removal of pollution or contaminants from the environment such as pollution in soils, ground or surface water and sediments.

Ecosystem engineers

Species which significantly alter, create or destroy habitats. These species can have a large impact on the biodiversity of an area. Because of this, they play an important role in maintaining their environment. The term tends to be limited to only keystone species, because all organisms affect the area where they live, even if this effect is minor.

Ecosystem services

The many and varied benefits to humans provided by the natural environment and from healthy ecosystems, e.g. clean air, food, carbon capture. See also natural capital.

Emergent properties

A property which a collection or complex system has, which the individual members alone do not have, that arises through interactions of the individual members. Emergent properties are novel and unpredictable because they are dependent on the collective behaviour of individual members. E.g. ant colonies exhibit properties that individual ants to not possess.

Environmental Land Management Scheme (ELM)

The incoming rural payment system which replace the Basic Payment Scheme and agri-environment schemes in the UK by 2028, based on the principle of public money for public goods’. Public goods include ecosystem services such as clean air and water, thriving wildlife, reduction in environmental hazards, climate change adaptation/​mitigation and beauty, heritage and engagement with the environment’.


Fortress Conservation

A derogatory term for the conservation model based on creating protected areas where ecosystems function in isolation from humans, often excluding local people

Functional diversity

An aspect of biodiversity relating to the range of behavioural traits of species that influence ecosystem dynamics through performing a range of ecological functions. Variation in such traits (which, for example in relation to feeding, could include grazing, browsing, predation, rootling) creates rich, dynamic ecological communities with functional processes (such as disturbance, regeneration and nutrient cycling).



An animal that eats grasses and herbs. See also: browser.



The place, environment or conditions where a plant or animal naturally or normally lives and grows.


The consumption of plant material by animals. Herbivores are animals adapted to eat plants.


The most recent geological epoch, which began approximately 10,000 years ago at the end of the last glacial period and still continues (others suggest the Holocene has ended and the Anthropocene has now begun).

Human rewilding

Human rewilding encourages the conscious undoing of human domestication and returning to the lifeways of some indigenous human cultures. Though often associated with primitive skills and learning knowledge of wild plants and animals, it emphasises regenerative land management techniques employed by hunter-gatherers and horticulturalists, as well as development of the senses and fostering deepening personal relationships with members of other species and the natural world. Human rewilding is considered a holistic approach to living, as opposed to specific or separate skills, practices or knowledges.


Invasive species

A non-native species that spreads from the point of introduction and becomes abundant. The invasive species label is usually only applied to species whose impact upon introduction has had a negative impact on the ecology of an area.

IUCN guidelines for conservation translocations

Guidelines produced by the IUCN (International Union for Conservation of Nature) for best practice of conservation translocations. The guidelines cover biological, social, and political ramifications, and provide the starting point for risk assessment and feasibility studies. Scotland now has its own version.


Keystone species

A species which has a disproportionately large effect on its natural environment relative to its abundance or biomass. Classic examples include wolves, beavers, sea otters and elephants. Keystone species play a significant role in defining the entire ecosystem they are found in, and often create habitat for other species. Without its keystone species, an ecosystem is dramatically different or may cease to exist altogether.


Land abandonment

The abandonment of land by humans and their associated impacts, usually on land that was previously managed, used or cultivated. It often results in a reinstatement of ecological processes such as succession. Often associated with farmers abandoning marginal land. See also passive rewilding and ecological rewilding.

Landscape-scale conservation

A holistic land management approach that involves the pursuit of multiple benefits (e.g. water quality, biodiversity) across a defined area (e.g. a catchment, estuary or other recognisable landscape unit) through working in collaboration and at a large scale.

Land sharing vs land sparing

An ongoing debate around approaches to improve biodiversity whilst maintaining food production. See land sparing and land sharing.

Land sharing

Low-yield farming, enabling biodiversity to be maintained within the agricultural landscape, though at lower levels than in reserves. Land-sharing farms can chip away at the size of the surrounding natural landscape and degrade its quality, threatening more widely ranging native species.

Land sparing

High-intensity agriculture, requiring a smaller area of land to attain the same yields, thereby leaving greater areas of wilder natural habitat intact. High-intensity practices on land-sparing farms, such as heavy planting, grazing, and use of fertiliser and pesticides, can threaten native species with small home ranges.

Lawton Report

Landmark Making Space for Nature’ report, chaired by Sir John Lawton in 2010; a government commissioned independent review of how England’s wildlife and ecological network could be improved to help nature thrive in the face of climate change and other pressures. The main conclusion was that we need to make our network of sites bigger, better, and more joined up’.


Managed metapopulation

A group of populations connected by human management, typically by translocating animals between populations to over come dispersal barriers, such as fences.


The large or giant animals of an area, habitat, or geological period. Thresholds for definition vary, but in rewilding the term generally refers to large-bodied terrestrial animals such as bears, bison, elk or (now-extinct) mammoths.


Natural capital

The world’s stock of natural resources, including geology, soils, air, water and all living organisms, many of which provide valuable benefits to humans, known as ecosystem services. Eg. a woodland can be a natural capital asset, from which flows ecosystem services such as flood risk reduction, carbon capture and clean air.

Natural Climate Solutions

Conservation, restoration and improved land management actions that increase carbon storage or avoid greenhouse gas emissions in landscapes (e.g. grasslands) across the globe. Research shows that Natural Climate Solutions can deliver up to a third of the emission reductions needed by 2030.

Natural disturbance

A temporary change in environmental conditions that causes a pronounced change in an ecosystem. Major disturbances (e.g. fires, storms, floods, clear felling) often act quickly and with great effect, but can also occur over a long period of time. Biodiversity is dependent on natural disturbance, with many species depending on disturbance events, e.g. shade-intolerant plant species rely on disturbance to provide light for successful establishment. Without this ongoing dynamism, diversity of forest flora can decline. Minor disturbance is created continually in a functional ecosystem, from browsing, rootling, large animals breaking through vegetation and trampling ground, and this creates opportunities for other species.

Naturalistic grazing

Grazing that aims to replicate natural grazing patterns as much as possible. Herbivore density is not specified – populations are resource-limited, so that numbers fluctuate according to factors such as food availability, climate, pathogens and parasites; grazing animals are assumed to drive the ecosystem, and natural processes are allowed to act, rather than being aimed at targets for habitat and species composition; direct management intervention is reduced to a minimum, and the natural process is seen as an aim in itself.

Natural process

Interactions among plants, animals, and the non-living components of the environment like climate or rocks. These interactions include photosynthesis, pollination, seed dispersal, grazing, decomposition and others. They are crucial for maintaining healthy ecosystems and supporting the long-term persistence of biodiversity.

Natural regeneration

The regeneration of trees and woodland through natural processes (e.g. seed dispersal), as opposed to planting by people.

Nature-based tourism

Responsible travel to natural areas, which aims to conserve the environment and boost local economies, e.g. birdwatching, photography, camping, hiking and visiting parks.

Nature connection

People’s subjective emotional, psychological and spiritual connection to the natural world, and activities that deepen it such as sensory awareness, nature education, survival skills and nature observation.

Nature-deficit disorder

Term coined by Richard Louv to describe the growing phenomenon of children spending less and less time outdoors and the associated behavioural effects this causes. It is not a medically recognised condition, but a term used to generally discuss the detrimental impacts of disconnection from nature.



Controversial nature reserve in the Netherlands on land reclaimed from the sea (polder), where Frans Vera conducted experiments with naturalistic grazing.


Passive management

A low-/non-intervention approach to land management.

Passive rewilding

The release of ecological processes as a result of humans ceasing to use, manage, or impact ecosystems. Often associated with or considered a by-product of farmers abandoning marginal land, but may be an intentional non-intervention approach to conservation. See also land abandonment and ecological rewilding.


Plantation on an Ancient Woodland site. An ancient woodland that was replanted with non-native species, usually for timber production. They often retain dormant ecological features of the native woodland and are a conservation restoration priority.


A set of design principles centered on whole systems thinking, which simulates or directly utilises the patterns observed in natural ecosystems. The term is usually applied to food growing but can also be applied to human systems.


The earliest epoch of the Quaternary period, between about 1,640,000 and 10,000 years ago, following the Pliocene and preceding the Holocene. The Pleistocene epoch was marked by great fluctuations in temperature, resulting in glacial and interglacial stages and corresponding falls and rises in sea level. The Pleistocene saw the appearance of the earliest forms of Homo sapiens, and the end of the final glacial stage marks the end of the epoch and the start of the Holocene.

Pleistocene rewilding

An approach to active rewilding that aims to recreate functioning ecosystems as they existed in the Pleistocene, using proxy species where necessary.


The preying of one animal on others.

Predation pressure

The effects of predation on a population of prey organisms especially with respect to the survival of the prey species. If predation pressure becomes too high, the prey species population will decrease, too low and it will increase; both have knock on effects in the ecosystem.

Process-led conservation

An approach to conservation with a focus on ecological processes as an end in itself, rather than a focus on specified end-points. In contrast to traditional target-led/species-led conservation that aims for specific end points such as % tree cover or specific abundances of rare species. Rewilding is an example.


(Also known as autotrophs) Organisms which produce their own food. Usually plants and algae, which use photosynthesis to manufacture their own food. See also consumer and decomposer

Proxy species

A species of animal used to replicate services provided by another that may be extinct, socially unacceptable or unavailable. E.g. Longhorn cattle are functionally similar to extinct aurochs, and konik ponies to the extinct tarpan.



A Restored Ancient Woodland Site. Usually restored (from non-native conifer plantation or PAWS) to >80% native broadleaf canopy cover.


The human-mediated movement of living organisms into an area where the species in question was historically native and has been made extinct. See also translocation.


The process of establishing trees or woodland in an area where there was previous tree cover. See afforestation and natural regeneration.

Regenerative farming/​agriculture

Agriculture that focuses on topsoil regeneration and other conservation objectives such as increasing biodiversity, improving water quality, enhancing and delivering ecosystem services and increasing our resilience to climate change.

Restoration (ecological)

The process of repairing ecosystems that have been degraded, damaged or destroyed by human activities, for example through watercourse pollution, introduction of invasive species, over-extraction, or eradication of native species. Debate around the difference between restoration and rewilding is ongoing and the terms are often used interchangeably, but restoration historically has placed greater emphasis on vegetation/​soil/​geomorphology as agents of recovery, bottom-up processes and human-led’ (nature-enabled’) approaches towards a specified end-point. (Compare with rewilding)


The large-scale restoration of ecosystems where nature can take care of itself. It seeks to reinstate natural processes and, where appropriate, missing species – allowing them to shape the landscape and the habitats within. Debate around the difference between restoration and rewilding is ongoing and the terms are often used interchangeably, but rewilding tends to focus on animals as agents of recovery (particularly predators and keystone species) and restoring ecological processes, emphasizing the importance of top-down processes, nature-led’ (human-enabled) approaches with no specified end-point, the Three Cs model’ and the importance of scale. Compare with ecological restoration.

Rootling /​rooting

With regard to animals such as wild boar, badgers and domestic pigs, the action of digging in the ground usually with the snout, for roots and invertebrates. Causes healthy disturbance to the soil. Benefits include allowing new plant species to germinate and breaking up dominating species such as grasses.



A habitat or plant community characterized by shrub domination, often also including grasses, herbs and small trees. It is usually a transitional phase between more open areas such as grassland or heathland and woodland, although a stable state may be maintained by regular natural disturbance such as fire or browsing. It is of high biodiversity value and has declined dramatically in recent decades with intensification of agriculture.

Seed source

The source of seed for (usually tree) planting or natural regeneration. Seed sources should represent the best available genetic material for planting as exhibited by the parent plant and be of local provenance. If there is no natural seed source nearby a given area, natural regeneration will not occur or be very slow, and planting may be necessary.

Shifting Baseline Syndrome

The phenomenon by which each successive generation perceives the environmental conditions in which they grew up as normal’. It also describes how people’s standards for acceptable environmental conditions are steadily declining.


Site of Special Scientific Interest (a national legally designated protected area).


The sequence of ecological changes in which one group of plant or animal species is replaced by another as part of the natural lifecycle of a landscape

Sympathetic management

Outcome-led conservation management where humans mimic natural processes on sites with clear objectives in mind.



Extinct primitive horse, ancestor of all current day horses.

Three Cs model

Cores, Corridors and Carnivores’ model often emphasised in rewilding approaches. The carnivores’ refers to the importance of apex predators (often keystone species) in an ecosystem. See Core wilderness area and Corridors.

Top-down processes

Processes driven by top level consumers (predators) and their prey, that influence lower trophic forms. See trophic level.

Translocation (Conservation)

Translocation is the human-mediated movement of living organisms from one area to another. The full spectrum of translocations includes reintroduction, reinforcement, and conservation introduction.

Trophic cascade

A trophic cascade is the propagation of indirect effects between nonadjacent trophic levels in a food chain or food web. They’re normally driven from the top, down the food chain. E.g. the number of apex predators at the top of the food chain affects the volume and diversity of primary producers through predatation of herbivores.

Trophic downgrading

The loss of species occupying the higher trophic levels, a human-induced trend present since the late Pleistocene. Large apex predators have been ubiquitous across the globe for millions of years until this time. The loss of these species has had extensive cascading effects in marine, terrestrial, and freshwater ecosystems, on processes as diverse as the dynamics of disease, wildfire, carbon sequestration, invasive species, and biogeochemical cycles.

Trophic interaction

Feeding interactions between trophic levels. E.g. the interaction between a grass and a deer would be a trophic interaction between a producer and a primary consumer. Trophic interactions are key determinants of population abundance and dynamics, the structure of ecological communities and the rate of ecosystem processes.

Trophic level

A group of organisms which occupy the same level in a food chain. There are five main trophic levels within a food chain: primary producers (plants and algae) which produce their own food through photosynthesis; primary consumers (herbivores which eat primary producers); secondary consumers (carnivores and omnivores which eat herbivores); tertiary consumers (carnivores and omnivores which eat secondary consumers); and apex predators, which have no natural predators. Decomposers consume dead plant and animal matter, converting it into energy and nutrients that plants can then use. Although they do not fill an independent trophic level, decomposers (eg fungi, bacteria, earthworms and flies) recycle waste material from all other trophic levels and are an important part of a functioning ecosystem.

Trophic rewilding

An ecological restoration strategy that uses species reintroductions to restore top-down processes and trophic interactions, and associated trophic cascades to promote self-regulating biodiverse ecosystems.


Urban rewilding

Rewilding applied to urban areas, focused on bringing nature and natural features into cities and towns. It includes creating habitat corridors with green roofs and walls, improving and increasing green spaces, street tree planting, and biophilic design. People benefit as well as wildlife, with improved mental and physical health.


Vera hypothesis

Ecological theory proposed by Frans Vera that posits that pre-human landscapes were not closed canopy forest as previously theorised, but a cycling wood pasture system with a continually changing landscape of open areas, scrub and woodland as natural disturbance shifted habitats. Now a widely accepted theory.



Similar to rewilding, with more emphasis on creating new, wilder ecosystems and less emphasis on past trends and patterns. Popularised by Isabella Tree’s book Wilding.

Wildlife corridor

See corridor

Wood pasture

A particularly high biodiversity value mosaic habitat made up of open grassy areas, scrub and denser woodland groves, varying depending on historic and current grazing/​management. Often contains veteran, ancient open-grown trees and large pieces of deadwood.



Term developed by Jennifer Wolch to describe the emergence of ethics, practice and politics of caring for animals and nature in cities. See also Urban rewilding

Dundreggan in autumn

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