Ecological indicator

Ecological indicators are used to communicate information about ecosystems and the impact human activity has on ecosystems to groups such as the public or government policy makers. Ecosystems are complex and ecological indicators can help describe them in simpler terms that can be understood and used by non-scientists to make management decisions. For example, the number of different beetle taxa found in a field can be used as an indicator of biodiversity.[1][2][3]

Many different types of indicators have been developed. They can be used to reflect a variety of aspects of ecosystems, including biological, chemical and physical. Due to this variety, the development and selection of ecological indicators is a complex process.[4]

Using ecological indicators is a pragmatic approach since direct documentation of changes in ecosystems as related to management measures, is cost and time intensive.[5][6] For example, it would be expensive and time-consuming to count every bird, plant and animal in a newly restored wetland to see if the restoration was a success. Instead, a few indicator species can be monitored to determine the success of the restoration.

"It is difficult and often even impossible to characterize the functioning of a complex system, such as an eco-agrosystem, by means of direct measurements. The size of the system, the complexity of the interactions involved, or the difficulty and cost of the measurements needed are often crippling"[7]

The terms ecological indicator and environmental indicator are often used interchangeably. However, ecological indicators are actually a sub-set of environmental indicators. Generally, environmental indicators provide information on pressures on the environment, environmental conditions and societal responses. Ecological indicators refer only to ecological processes; however, sustainability indicators are seen as increasingly important for managing humanity's coupled human-environmental systems[1].

Ecological indicators play an important role in evaluating policy regarding the environment.

Indicators contribute to evaluation of policy development by:[8]

  • Providing decision-makers and the general public with relevant information on the current state and trends in the environment.
  • Helping decision-makers better understand cause and effect relationships between the choices and practices of businesses and policy-makers versus the environment.
  • Assisting to monitor and assess the effectiveness of measures taken to increase and enhance ecological goods and services.

Based on the United Nations convention to combat desertification and convention for biodiversity, indicators are planned to be built in order to evaluate the evolution of the factors. For instance, for the CCD, the Unesco-funded Observatoire du Sahara et du Sahel (OSS) has created the Réseau d'Observatoires du Sahara et du Sahel (ROSELT) (website [9]) as a network of cross-Saharan observatories to establish ecological indicators.


There are limitations and challenges to using indicators for evaluating policy programs.

For indicators to be useful for policy analysis, it is necessary to be able to use and compare indicator results on different scales (local, regional, national and international). Currently, indicators face the following spatial limitations and challenges:

  1. Variable availability of data and information on local, regional and national scales.
  2. Lack of methodological standards on an international scale.
  3. Different ranking of indicators on an international scale which can result in different legal treatment.
  4. Averaged values across a national level may hide regional and local trends.
  5. When compiled, local indicators may be too diverse to provide a national result.[10]

Indicators also face other limitations and challenges, such as:

  1. Lack of reference levels, therefore it is unknown if trends in environmental change are strong or weak.
  2. Indicator measures can overlap, causing over estimation of single parameters.
  3. Long-term monitoring is necessary to identify long-term environmental changes.
  4. Attention to more easily handled measurable indicators distracts from indicators less quantifiable such as aesthetics, ethics or cultural values. [11]

See also


  1. ^ Bertollo, P. (1998). "Assessing ecosystem health in governed landscapes: A framework for developing core indicators". Ecosystem Health. 4: 33–51. doi:10.1046/j.1526-0992.1998.00069.x.
  2. ^ Girardin, P., Bockstaller, C. & Van der Werf, H. (1999). "Indicators: Tools to evaluate the environmental impacts of farming systems". Journal of Sustainable Agriculture. 13 (4): 6–21. doi:10.1300/J064v13n04_03.CS1 maint: Multiple names: authors list (link)
  3. ^ Kurtz, J.C., Jackson, L.E. & Fisher, W.S.. (2001). "Strategies for evaluating indicators based on guidelines from the Environmental Protection Agency's Office of Research and Development". Ecological Indicators. 1: 49–60. CiteSeerX doi:10.1016/S1470-160X(01)00004-8.CS1 maint: Multiple names: authors list (link)
  4. ^ Niemeijer, D. (2002). "Developing indicators for environmental policy: data-driven and theory-driven approaches examined by example". Environmental Science and Policy. 5 (2): 91–103. doi:10.1016/S1462-9011(02)00026-6.
  5. ^ Osinski, E.; Meier, U.; Büchs, W.; Weickel, J. & Matzdorf, B. (2003). "Application of biotic indicators for evaluation of sustainable land use – current procedures and future developments". Agriculture, Ecosystems and Environment. 98 (1–3): 407–421. doi:10.1016/S0167-8809(03)00100-2.
  6. ^ Piorr, H.P. (2003). "Environmental policy, agri-environmental indicators and landscape indicators". Agriculture, Ecosystems and Environment. 98 (1–3): 17–33. CiteSeerX doi:10.1016/S0167-8809(03)00069-0.

External links

  1. ^ Shaker, R. R. (2018). A mega-index for the Americas and its underlying sustainable development correlations. Ecological Indicators, 89, 466-479.
Abiotic component

In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them underpin all biology.

Abiotic components include physical conditions and non-living resources that affect living organisms in terms of growth, maintenance, and reproduction. Resources are distinguished as substances or objects in the environment required by one organism and consumed or otherwise made unavailable for use by other organisms.

Component degradation of a substance occurs by chemical or physical processes, e.g. hydrolysis. All non-living components of an ecosystem, such as atmospheric conditions and water resources, are called abiotic components.


Bacterivores are free-living, generally heterotrophic organisms, exclusively microscopic, which obtain energy and nutrients primarily or entirely from the consumption of bacteria. Many species of amoeba are bacterivores, as well as other types of protozoans. Commonly, all species of bacteria will be prey, but spores of some species, such as Clostridium perfringens, will never be prey, because of their cellular attributes.


A copiotroph is an organism found in environments rich in nutrients, particularly carbon. They are the opposite to oligotrophs, which survive in much lower carbon concentrations.

Copiotrophic organisms tend to grow in high organic substrate conditions. For example, copiotrophic organisms grow in Sewage lagoons. They grow in organic substrate conditions up to 100x higher than oligotrophs.


Decomposers are organisms that break down dead or decaying organisms, and in doing so, they carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. While the terms decomposer and detritivore are often interchangeably used, detritivores must ingest and digest dead matter via internal processes while decomposers can directly absorb nutrients through chemical and biological processes hence breaking down matter without ingesting it. Thus, invertebrates such as earthworms, woodlice, and sea cucumbers are technically detritivores, not decomposers, since they must ingest nutrients and are unable to absorb them externally.

Dominance (ecology)

Ecological dominance is the degree to which a taxon is more numerous than its competitors in an ecological community, or makes up more of the biomass.

Most ecological communities are defined by their dominant species.

In many examples of wet woodland in western Europe, the dominant tree is alder (Alnus glutinosa).

In temperate bogs, the dominant vegetation is usually species of Sphagnum moss.

Tidal swamps in the tropics are usually dominated by species of mangrove (Rhizophoraceae)

Some sea floor communities are dominated by brittle stars.

Exposed rocky shorelines are dominated by sessile organisms such as barnacles and limpets.

Energy Systems Language

The Energy Systems Language, also referred to as Energese, Energy Circuit Language, or Generic Systems Symbols, was developed by the ecologist Howard T. Odum and colleagues in the 1950s during studies of the tropical forests funded by the United States Atomic Energy Commission. They are used to compose energy flow diagrams in the field of systems ecology.

Feeding frenzy

In ecology, a feeding frenzy occurs when predators are overwhelmed by the amount of prey available. For example, a large school of fish can cause nearby sharks, such as the lemon shark, to enter into a feeding frenzy. This can cause the sharks to go wild, biting anything that moves, including each other or anything else within biting range. Another functional explanation for feeding frenzy is competition amongst predators. This term is most often used when referring to sharks or piranhas. It has also been used as a term within journalism.


A lithoautotroph or chemolithoautotroph is a microbe which derives energy from reduced compounds of mineral origin. Lithoautotrophs are a type of lithotrophs with autotrophic metabolic pathways. Lithoautotrophs are exclusively microbes; macrofauna do not possess the capability to use mineral sources of energy. Most lithoautotrophs belong to the domain Bacteria, while some belong to the domain Archaea. For lithoautotrophic bacteria, only inorganic molecules can be used as energy sources. The term "Lithotroph" is from Greek lithos (λίθος) meaning "rock" and trōphos (τροφοσ) meaning "consumer"; literally, it may be read "eaters of rock". Many lithoautotrophs are extremophiles, but this is not universally so.

Lithoautotrophs are extremely specific in using their energy source. Thus, despite the diversity in using inorganic molecules in order to obtain energy that lithoautotrophs exhibit as a group, one particular lithoautotroph would use only one type of inorganic molecule to get its energy.

Mesotrophic soil

Mesotrophic soils are soils with a moderate inherent fertility. An indicator of soil fertility is its base status, which is expressed as a ratio relating the major nutrient cations (calcium, magnesium, potassium and sodium) found there to the soil's clay percentage. This is commonly expressed in hundredths of a mole of cations per kilogram of clay, i.e. cmol (+) kg−1 clay.


Microecosystems can exist in locations which are precisely defined by critical environmental factors within small or tiny spaces.

Such factors may include temperature, pH, chemical milieu, nutrient supply, presence of symbionts or solid substrates, gaseous atmosphere (aerobic or anaerobic) etc.


A mycotroph is a plant that gets all or part of its carbon, water, or nutrient supply through symbiotic association with fungi. The term can refer to plants that engage in either of two distinct symbioses with fungi:

Many mycotrophs have a mutualistic association with fungi in any of several forms of mycorrhiza. The majority of plant species are mycotrophic in this sense. Examples include Burmanniaceae.

Some mycotrophs are parasitic upon fungi in an association known as myco-heterotrophy.


An organotroph is an organism that obtains hydrogen or electrons from organic substrates. This term is used in microbiology to classify and describe organisms based on how they obtain electrons for their respiration processes. Some organotrophs such as animals and many bacteria, are also heterotrophs. Organotrophs can be either anaerobic or aerobic.

Antonym: Lithotroph, Adjective: Organotrophic.


Overpopulation occurs when a species' population exceeds the carrying capacity of its ecological niche. It can result from an increase in births (fertility rate), a decline in the mortality rate, an increase in immigration, or an unsustainable biome and depletion of resources. When overpopulation occurs, individuals limit available resources to survive.

The change in number of individuals per unit area in a given locality is an important variable that has a significant impact on the entire ecosystem.


A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton.

Population cycle

A population cycle in zoology is a phenomenon where populations rise and fall over a predictable period of time. There are some species where population numbers have reasonably predictable patterns of change although the full reasons for population cycles is one of the major unsolved ecological problems. There are a number of factors which influence population change such as availability of food, predators, diseases and climate.

Recruitment (biology)

In biology, especially marine biology, recruitment occurs when a juvenile organism joins a population, whether by birth or immigration, usually at a stage whereby the organisms are settled and able to be detected by an observer.There are two types of recruitment: closed and open.In the study of fisheries, recruitment is "the number of fish surviving to enter the fishery or to some life history stage such as settlement or maturity".

Relative abundance distribution

In the field of ecology, the relative abundance distribution (RAD) or species abundance distribution describes the relationship between the number of species observed in a field study as a function of their observed abundance. The graphs obtained in this manner are typically fitted to a Zipf–Mandelbrot law, the exponent of which serves as an index of biodiversity in the ecosystem under study.

River Syfynwy

River Syfynwy (Welsh: Afon Syfynwy, Syfnwy or Syfni) is a river entirely within Pembrokeshire, Wales, rising in the Preseli Hills, feeding the Rosebush and Llys y Fran reservoirs and joining the Eastern Cleddau to the south. It is a river considered to be important as an ecological indicator and part is in a site of special scientific interest.

Species homogeneity

In ecology, species homogeneity is a lack of biodiversity. Species richness is the fundamental unit in which to assess the homogeneity of an environment. Therefore, any reduction in species richness, especially endemic species, could be argued as advocating the production of a homogenous environment.

Main fields
Related fields
See also
Food webs
Example webs
Ecology: Modelling ecosystems: Other components


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