Glossary⁷

Connectivity (ecological). See Ecological connectivity.

Degradation (of an ecosystem) — 1) A persistent deterioration of the attributes of an ecosystem (e.g. abiotic condition, species composition, ecosystem structure and function, external exchanges) relative to reference conditions, due to direct (e.g. unsustainable resource use, land use change, overexploitation, contamination) or indirect (e.g. climate change) human intervention, that affects the ecosystem’s capacity to provide benefits to people and nature. (Nelson et al., 2024) 2) A level of deleterious human impact to ecosystems that results in the loss of biodiversity and simplification or disruption in their composition, structure and functioning, and generally leads to a reduction in the flow of ecosystem services (Gann et al., 2019).

Ecological connectivity — The unimpeded movement of species, connection of habitats without hindrance, and the flow of natural processes that sustain life on Earth (UNEP/CMS/Resolution 14.16). See also “Guidelines for conserving connectivity through ecological networks and corridors” (Hilty et al., 2020).

Ecological integrity — An ecosystem’s capacity to maintain its characteristic composition, structure, functioning and self-organization over time within a natural range of variability (Pimentel and Edwards, 2000).

Ecosystem restoration — The process of halting and reversing degradation, resulting in improved ecosystem services and recovered biodiversity. Ecosystem restoration encompasses a wide continuum of practices, depending on local conditions and societal choice (UNEP, 2021; FAO et al., 2021). See also “Principles for ecosystem restoration to guide the United Nations Decade 2021–2030” (FAO et al., 2021).

Ecological restoration — One of a broad array of restorative management activities that are considered ecosystem restoration under the UN Restoration Decade. Ecological restoration is broadly defined as the process of assisting in the recovery of an ecosystem that has been damaged, degraded or destroyed (Gann et al., 2019). It differs from other ecosystem restoration activities in that it aims to recover a natural ecosystem or landscape to the condition it would be in had degradation not occurred, while allowing for environmental change (such as increases in temperature or variation in precipitation patterns caused by climate change). Ecological restoration seeks to recover biodiversity and ecosystem integrity, while delivering ecosystem service and ensuring human well-being. The conservation and restoration of biological diversity is a primary goal.

Forest (and) Landscape Restoration (FLR) — This concept emerged in 2000 and has since gained significant policy relevance reflected by the adoption of the Bonn Challenge. The Global Partnership on Forest and Landscape Restoration defines FLR as “a process that aims to regain ecological functionality and enhance human well-being in deforested or degraded landscapes” (Besseau et al., 2018). FLR is not an end in itself, but a means of regaining, improving, and maintaining vital ecological and social functions, in the long term leading to more resilient and sustainable landscapes. Many types of ecosystem restoration interventions are used to implement FLR, which aims to improve both ecological and social conditions across a mosaic of land uses.

Indigenous Peoples’ biocentric restoration — Indigenous Peoples’ biocentric and biocultural restoration are recognized as inclusive and rights-based, and grounded in the knowledge of territorial management of Indigenous Peoples. From a biocentric perspective, Indigenous Peoples place their cosmogony and belief systems, the environment and biodiversity at the centre of their restoration practices, in both natural and semi-natural ecosystems. (Nelson et al., 2024).

Indigenous Peoples´ Knowledge — There is no single definition of Indigenous Knowledge. For our purposes, we understand ‘Indigenous Knowledge’ as a term that refers to a set of complex knowledge systems based on the worldviews of Indigenous Peoples. Indigenous Knowledge reflects the unique cultures, languages, values, histories, governance and legal systems of Indigenous Peoples. It is place-based, cumulative and dynamic. Indigenous Knowledge systems involve living well with, and being in relationship with, the natural world. Indigenous Knowledge systems build upon the experiences of earlier generations, inform the practice of current generations, and evolve in the context of contemporary society. It is important to note that some Indigenous communities are struggling to maintain their Indigenous Knowledge due to ongoing impacts of colonialism. To ensure Indigenous Peoples have data sovereignty, it is important to respect their decisions on knowledge sharing, and ensuring their access, use and control over their data.

Inland waters — Aquatic-influenced environments located within land boundaries. This definition includes all possible kinds of inland water body or ecosystem, or components thereof, including groundwater.

Land degradation — 1) The many processes that drive the decline or loss in biodiversity, ecosystem functions or their benefits to people; includes the degradation of all terrestrial ecosystems (IPBES, 2018b). 2) The loss of biological or economic productivity and complexity in agricultural, range or forest land due to processes arising from human activities, such as the erosion or deterioration of soil and the loss of natural vegetation (UNCCD, 2019).

Land Degradation Neutrality (LDN) — The UNCCD defines this as “a state whereby the amount and quality of land resources necessary to support ecosystem functions and services to enhance food security remain stable, or increase, within specified temporal and spatial sales and ecosystems.”

Landscape — A bounded area (at any spatial scale) of interacting ecosystems with discrete ecological composition, structures and functions, and human communities with discrete socioeconomic and cultural characteristics (Nelson et al., 2024).

Natural ecosystems (habitats) — Areas composed of viable assemblages of plant and/or animal species of largely native origin and/or where human activity had not essentially modified an area's primary ecological functions and species composition. (Based on UNEP-WCMC definition of natural habitats). https://www.cbd.int/doc/c/c3ab/388d/950ddc02586468a814120acf/wg2020-05-04-en.pdf

Net gain — A positive improvement from restoration’s contributions to biodiversity, ecosystem integrity and human well-being, using the degraded state as a baseline, and measured at appropriate temporal and spatial scales. Measurement of net gain should include intended as well as unintended consequences of restoration activities, within and outside the restoration site. Because net gain by definition is measured against the degraded baseline, it only applies to ecosystems that have been degraded (i.e. it is not appropriate to measure net gain of non-degraded ecosystems) (Nelson et al., 2024, modified from outputs of the third Global Forum on Ecological Restoration, hosted by SER and IUCN CEM, 2021).

Production ecosystems — Systems that society relies on for food, feed and fibre production. In these systems ecosystem restoration is primarily seen as contributing to healthy and stable ecosystems, which in turn support human needs for sustainable food production and livelihoods (FAO, 2020).

Reclamation — The process of making severely degraded land (e.g. former mine sites or wastelands) fit for cultivation or a state suitable for some human use, such as its former or an alternative land use. Historically, it has also been used to describe the formation of productive land from the sea through the process of transformation (Adapted from Gann et al., 2019; Young et al., 2022).

Recovery — The process by which an ecosystem regains its composition, structure and function relative to the levels identified for the reference ecosystem. In restoration, recovery usually is assisted by restoration activities–and recovery can be described as partial or full (Gann et al., 2019).

Reference model — A model that characterizes the ecological condition that the restoration project site would be in if degradation had not occurred. Because an inherent property of ecosystems is that they change over time, the goal of this model is not to characterize pre-disturbance conditions, but rather the condition that the site would have been in now, which incorporates potential change over time. The reference model provides information on mean and variation in each element of ecosystem integrity, including species composition, ecosystem structure and functions, physical conditions, and ecological connectivity with the larger landscape or seascape. Reference models are developed using multiple sources of information. Best practice is to construct reference models empirically from a suitable number of reference sites, augmented with best available information from multiple other sources. For heavily impacted landscapes, there may be an insufficient number of (or no) available reference sites. In these cases, other information sources, such as successional models and historical information from natural and written archives, must be used to construct a theoretical reference model (adapted from Nelson et al., 2024; Gann et al., 2019).

Reference site — A site that is environmentally similar to the project site (site to undergo restoration) but that has experienced little to no anthropogenic degradation. Where available, an appropriate number of reference sites can be used to reliably characterize the mean condition (and range of variability) that the restoration project site would have been in had degradation not occurred (Adapted from Gann et al., 2019; Nelson et al., 2024).

Rehabilitation — Management actions that reinstate attributes of some physical properties (e.g. soils, water) and a level of ecosystem functioning on degraded or transformed sites, along with renewed and ongoing provision of a level of ecosystem services. Native biodiversity and ecosystem integrity are supported but actions do not achieve substantive recovery of a natural ecosystem.

Restoration — The term restoration, in the broad sense, is generally consistent with the definition of ecosystem restoration (below), but can also be used to refer to ecological restoration, Forest Landscape Restoration, or even broader concepts, some of which have a stronger emphasis on human well-being.

Restoration ecology — The branch of ecological science that provides concepts, models, methodologies and tools for the practice of ecological restoration. It also benefits from direct observation of and participation in restoration practice. (Gann et al., 2019)

Restorative continuum — The range of ecosystem restoration activities ordered based on the degree to which they recover biodiversity, ecosystem health and integrity, and human well-being. At one end of this continuum are management activities aimed at reducing societal impacts, such as runoff into urban streams, and mitigating threats such as contaminated soils. The other end of the continuum includes ecological restoration, which aims to both remove degradation and recover ecosystems to the condition that they would be in had degradation not occurred, while allowing for environmental change. (Nelson et al., 2024, adapted from the definition by Gann et al., 2019)

Rewilding — The process of rebuilding–following major human disturbance–a natural ecosystem by restoring natural processes and the complete or near complete food web at all trophic levels as a self-sustaining and resilient ecosystem with biota that would have been present had the disturbance not occurred (Carver et al., 2021). Some consider rewilding as a unique component of ecological restoration, while others consider it to be its own discipline.

Rights and knowledge holders — Any person, group of persons or entity who holds customary or legal use rights, in accordance with the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP) and national laws or traditions, and the recommendations of the United Nations Permanent Forum on Indigenous Issues (UNPFII). (Adapted from Nelson et al., 2024, Preferred by Nature’s 2022). In some parts of the world (e.g. Canada) knowledge holders are a distinct subset of individuals within rights holder communities.

Seascape — A bounded area of interacting ecosystems (at any spatial scale) in marine environments, with discrete ecological composition, structures and functions, and human communities with discrete socioeconomic and cultural characteristics. (Nelson et al., 2024)

Semi-natural ecosystems — In the European Union (EU) legal context, these are biodiverse ecological assemblages created by human activities (e.g. grazed or mowed alpine meadows). They have evolved under traditional agricultural, pastoral or other human activities that can be centuries old and depend on traditional management for their characteristic composition, structure and function. These ecosystems are highly valued for their biodiversity and ecosystem services and can be a reference for ecological restoration. Examples include alpine and lowland meadows, heathlands, chalk grasslands, coppice forests, wood pastures and grazing marshes. They differ from “cultural ecosystems,” as defined by the European Union, created to provide ecosystem services, but that result in degraded ecosystems with lower biodiversity values. Examples include arable fields, species-poor agricultural grasslands, mineral extraction areas and urban landscapes with city parks. These are not appropriate as a reference for ecological restoration but can be the starting point for ecological restoration or rehabilitation. (Modified from Gann et al., 2019)

© FAO