Glossary | 283

earned in kind (e.g., growing food for consumption by
the same household).
Cultivar A cultivated variety, a population of plants within a
species of plant. Each cultivar or variety is genetically
Deforestation The action or process of changing forest land
to non-forested land uses.
Degradation The result of processes that alter the ecological
characteristics of terrestrial or aquatic (agro)ecosystems
so that the net services that they provide are reduced.
Continued degradation leads to zero or negative eco-
nomic agricultural productivity.
For loss of land in quantitative or qualitative ways,
the term degradation is used. For water resources ren-
dered unavailable for agricultural and nonagricultural
uses, we employ the terms depletion and pollution. Soil
degradation refers to the processes that reduce the capac-
ity of the soil to support agriculture.
Desertification Land degradation in drylands resulting from
various factors, including climatic variations and human
Domesticated or Cultivated Species Species in which the
evolutionary process has been influenced by humans to
meet their needs.
Domestication The process to accustom animals to live with
people as well as to selectively cultivate plants or raise
animals in order to increase their suitability and compat-
ibility to human requirements.
Driver Any natural or human-induced factor that directly or
indirectly causes a change in a system.
Driver, direct A driver that unequivocally influences ecosys-
tem processes and can therefore be identified and mea-
sured to different degrees of accuracy.
Driver, endogenous A driver whose magnitude can be in-
fluenced   by  the   decision-maker.   The   endogenous   or
exogenous characteristic of a driver depends on the orga-
nizational scale. Some drivers (e.g., prices) are exogenous
to a decision-maker at one level (a farmer) but endog-
enous at other levels (the nation-state).
Driver, exogenous A driver that cannot be altered by the
Driver, indirect A driver that operates by altering the level or
rate of change of one or more direct drivers.
Ecoagriculture A    management    approach    that    provides
fair balance between production of food, feed, fuel, fi-
ber, and biodiversity conservation or protection of the
Ecological Pest Management (EPM) A strategy to man-
age pests that focuses on strengthening the health and
resilience of the entire agro-ecosystem. EPM relies on
scientific advances in the ecological and entomological
fields of population dynamics, community and landscape
ecology, multi-trophic interactions, and plant and habitat
Economic Rate of Return The net benefits to all members
of society as a percentage of cost, taking into account
externalities and other market imperfections.
Ecosystem A dynamic complex of plant, animal, and micro-
organism communities and their nonliving environment
interacting as a functional unit.
Ecosystem Approach A strategy for the integrated manage-


ment of land, water, and living resources that promotes
conservation and sustainable use in an equitable way.
An ecosystem approach is based on the application of appropri-
ate scientific methodologies focused on levels of biologi-
cal organization, which encompass the essential structure,
processes, functions, and interactions among organisms
and their environment. It recognizes that humans, with
their cultural diversity, are an integral component and
managers of many ecosystems.
Ecosystem  Function An  intrinsic ecosystem characteristic
related to the set of conditions and processes whereby
an ecosystem maintains its integrity (such as primary
productivity, food chain biogeochemical cycles). Ecosys-
tem functions include such processes as decomposition,
production, pollination, predation, parasitism, nutrient
cycling, and fluxes of nutrients and energy.
Ecosystem Management An approach to maintaining or re-
storing the composition, structure, function, and delivery
of services of natural and modified ecosystems for the
goal of achieving sustainability. It is based on an adap-
tive, collaboratively developed vision of desired future
conditions that integrates ecological, socioeconomic, and
institutional perspectives, applied within a geographic
framework, and defined primarily by natural ecological
Ecosystem  Properties The size, biodiversity, stability, de-
gree of organization, internal exchanges of material and
energy among different pools, and other properties that
characterize an ecosystem.
Ecosystem Services The benefits people obtain from ecosys-
tems. These include provisioning services such as food
and water; regulating services such as flood and disease
control; cultural services such as spiritual, recreational,
and cultural benefits; and supporting services such as
nutrient cycling that maintain the conditions for life on
Earth. The concept "ecosystem goods and services" is
synonymous with ecosystem services.
Ecosystem Stability A description of the dynamic proper-
ties of an ecosystem. An ecosystem is considered stable
if it returns to its original state shortly after a perturba-
tion (resilience), exhibits low temporal variability (con-
stancy), or does not change dramatically in the face of a
perturbation (resistance).
Eutrophication Excessive enrichment of waters with nutri-
ents, and the associated adverse biological effects.
Ex-ante The analysis of the effects of a policy or a project
based only on information available before the policy or
project is undertaken.
Ex-post The analysis of the effects of a policy or project based
on information available after the policy or project has
been implemented and its performance is observed.
Ex-situ Conservation The conservation of components of
biological diversity outside their natural habitats.
Externalities Effects of a person's or firm's activities on oth-
ers which are not compensated. Externalities can either
hurt or benefit others—they can be negative or positive.
One negative externality arises when a company pollutes
the local environment to produce its goods and does not
compensate the negatively affected local residents. Posi-
tive externalities can be produced through primary edu-
cation—which benefits not only primary school students