Abundance (ecology)

In ecology, local abundance is the relative representation of a species in a particular ecosystem.^[1] It is usually measured as the number of individuals found per sample. The ratio of abundance of one species to one or multiple other species living in an ecosystem is referred to as relative species abundances.^[1] Both indicators are relevant for computing biodiversity.

A variety of sampling methods are used to measure abundance. For larger animals, these may include spotlight counts, track counts and roadkill counts, as well as presence at monitoring stations.^[2] In many plant communities the abundances of plant species are measured by plant cover, i.e. the relative area covered by different plant species in a small plot.^[3] Abundance is in simplest terms usually measured by identifying and counting every individual of every species in a given sector. It is common for the distribution of species to be skewed so that a few species take up the bulk of individuals collected.^[4]

Relative species abundance is calculated by dividing the number of species from one group by the total number of species from all groups.

Community ecology

These measures are all a part of community ecology. Understanding patterns within a community is easy when the community has a relatively low number of species. However most communities do not have a low number of species.^[4] Measuring species abundance allows for understanding of how species are distributed within an ecosystem.^[4] For example, salt water marshes have an influx of sea water, causing only a few species which are adapted to be able to survive in both salt and fresh water to be abundant. Inversely in land locked wetlands, the species abundance is more evenly distributed among the species who live within the wetland.^[4]

In most ecosystems in which abundance has been calculated, most often only a small number of species are abundant, while a large number are pretty rare.^[4] These abundant species are often generalists, with many rare species being specialists.^[4] High density of a species in multiple localities will usually lead to it being relatively abundant over all in an ecosystem.^[4] Therefore, high local abundance can be directly linked to high regional distribution. Species with high abundance are likely to have more offspring, and these offspring in turn are more likely to colonize a new sector of the ecosystem than a species which is less abundant. Thus begins a positive feedback loop leading to a species distribution in which a few "core species" are wide spread, and the other species are restricted and scarce known as satellite species.^[1]

Species abundance distribution

Species abundance distribution (SAD) is one of the main uses of this measurement. SAD is a measurement of how common, or rare species are within an ecosystem.^[5] This allows researchers to assess how different species are distributed throughout an ecosystem. SAD is one of the most basic measurements in ecology and is used very often, therefore many different methods of measurement and analysis have developed.^[5]

Measurement

There are several methods for measuring abundance. An example of this is Semi-Quantitive Abundance ratings.^[6] These are measurement methods which involve estimation based on viewing a specific area of a designated size.^[6] The two Semi-Quantitive Abundance ratings used are known as the D.A.F.O.R, and the A.C.F.O.R.^[6]

The A.C.F.O.R. scale is as follows:

A – Species observed is "Abundant" within the given area.
C – Species observed is "Common" within the given area.
F – Species observed is "Frequent" within the given area.
O – Species observed is "Occasional" within the given area
R – Species observed is "Rare" within the given area.

D.A.F.O.R scale:

D - Species observed is "Dominant" in a given area.
A - Species observed is "Abundant" in a given area.
F - Species observed is "Frequent" in a given area.
O - Species observed is "Occasional" in a given area.
R - Species observed is "Rare" in a given area.

These methods are useful for getting a rough estimate of the species abundance in a designated area (quadrant), but they are not exact or objective measurements. Therefore, if another method of measuring abundance is available, it should be used, as this will lead to more useful and quantifiable data.^[6]

References

^ ^a ^b ^c Preston, F.W. (July 1948). "The Commonness, and Rarity, of Species" (PDF). Ecology. 29 (3): 254–283. doi:10.2307/1930989. JSTOR 1930989. Archived from the original (PDF) on 2014-12-22. Retrieved 2019-02-12 – via Ben-Gurion University of the Negev.
^ Wright, David Hamilton (July 1991). "Correlations Between Incidence and Abundance are Expected by Chance". Journal of Biogeography. 18 (4). Journal of Biogeography, Vol. 18, No. 4: 463–466. doi:10.2307/2845487. JSTOR 2845487.
^ Damgaard, Christian (2009). "On the distribution of plant abundance data". Ecological Informatics. 4 (2): 76–82. doi:10.1016/j.ecoinf.2009.02.002.
^ ^a ^b ^c ^d ^e ^f ^g Verberk, W (2011). "Explaining General Patterns in Species Abundance and Distributions". Nature Education Knowledge. 3 (10): 38 – via researchgate.
^ ^a ^b Baldridge E, Harris DJ, Xiao X, White EP. 2016. An extensive comparison of species-abundance distribution models. PeerJ 4:e2823 https://doi.org/10.7717/peerj.2823
^ ^a ^b ^c ^d Morris, Peter (1995). Methods of Environmental Assessment. University College London Press. p. 236.

External links

"Abundance in ecology" (article, with works cited)

[:0-1] Preston, F.W. (July 1948). "The Commonness, and Rarity, of Species" (PDF). Ecology. 29 (3): 254–283. doi:10.2307/1930989. JSTOR 1930989. Archived from the original (PDF) on 2014-12-22. Retrieved 2019-02-12 – via Ben-Gurion University of the Negev.

[2] Wright, David Hamilton (July 1991). "Correlations Between Incidence and Abundance are Expected by Chance". Journal of Biogeography. 18 (4). Journal of Biogeography, Vol. 18, No. 4: 463–466. doi:10.2307/2845487. JSTOR 2845487.

[3] Damgaard, Christian (2009). "On the distribution of plant abundance data". Ecological Informatics. 4 (2): 76–82. doi:10.1016/j.ecoinf.2009.02.002.

[:3-4] ^ ^a ^b ^c ^d ^e ^f ^g Verberk, W (2011). "Explaining General Patterns in Species Abundance and Distributions". Nature Education Knowledge. 3 (10): 38 – via researchgate.

[:2-5] Baldridge E, Harris DJ, Xiao X, White EP. 2016. An extensive comparison of species-abundance distribution models. PeerJ 4:e2823 https://doi.org/10.7717/peerj.2823

[:1-6] Morris, Peter (1995). Methods of Environmental Assessment. University College London Press. p. 236.

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v t e Ecology: Modelling ecosystems: Trophic components
General	Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Green world hypothesis Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Resource Restoration
Producers	Autotrophs Chemosynthesis Chemotrophs Foundation species Kinetotrophs Mixotrophs Myco-heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production
Consumers	Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredators Mesopredator release hypothesis Omnivores Optimal foraging theory Planktivore Predation Prey switching
Decomposers	Chemoorganoheterotrophy Decomposition Detritivores Detritus
Microorganisms	Archaea Bacteriophage Lithoautotroph Lithotrophy Marine Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology
Food webs	Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level
Example webs	Lakes Rivers Soil Tritrophic interactions in plant defense Marine food webs cold seeps hydrothermal vents intertidal kelp forests North Pacific Gyre San Francisco Estuary tide pool
Processes	Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer–resource interactions Copiotrophs Dominance Ecological network Ecological succession Energy quality Energy systems language f-ratio Feed conversion ratio Feeding frenzy Mesotrophic soil Nutrient cycle Oligotroph Paradox of the plankton Trophic cascade Trophic mutualism Trophic state index
Defense, counter	Animal coloration Anti-predator adaptations Camouflage Deimatic behaviour Herbivore adaptations to plant defense Mimicry Plant defense against herbivory Predator avoidance in schooling fish

v t e Ecology: Modelling ecosystems: Other components
Population ecology	Abundance Allee effect Consumer-resource model Depensation Ecological yield Effective population size Intraspecific competition Logistic function Malthusian growth model Maximum sustainable yield Overpopulation Overexploitation Population cycle Population dynamics Population modeling Population size Predator–prey (Lotka–Volterra) equations Recruitment Small population size Stability Resilience Resistance Random generalized Lotka–Volterra model
Species	Biodiversity Density-dependent inhibition Ecological effects of biodiversity Ecological extinction Endemic species Flagship species Gradient analysis Indicator species Introduced species Invasive species / Native species Latitudinal gradients in species diversity Minimum viable population Neutral theory Occupancy–abundance relationship Population viability analysis Priority effect Rapoport's rule Relative abundance distribution Relative species abundance Species diversity Species homogeneity Species richness Species distribution Species–area curve Umbrella species
Species interaction	Antibiosis Biological interaction Commensalism Community ecology Ecological facilitation Interspecific competition Mutualism Parasitism Storage effect Symbiosis
Spatial ecology	Biogeography Cross-boundary subsidy Ecocline Ecotone Ecotype Disturbance Edge effects Foster's rule Habitat fragmentation Ideal free distribution Intermediate disturbance hypothesis Insular biogeography Land change modeling Landscape ecology Landscape epidemiology Landscape limnology Metapopulation Patch dynamics r/K selection theory Resource selection function Source–sink dynamics
Niche	Ecological niche Ecological trap Ecosystem engineer Environmental niche modelling Guild Habitat marine habitats Limiting similarity Niche apportionment models Niche construction Niche differentiation Ontogenetic niche shift
Other networks	Assembly rules Bateman's principle Bioluminescence Ecological collapse Ecological debt Ecological deficit Ecological energetics Ecological indicator Ecological threshold Ecosystem diversity Emergence Extinction debt Kleiber's law Liebig's law of the minimum Marginal value theorem Thorson's rule Xerosere
Other	Allometry Alternative stable state Balance of nature Biological data visualization Ecological economics Ecological footprint Ecological forecasting Ecological humanities Ecological stoichiometry Ecopath Ecosystem based fisheries Endolith Evolutionary ecology Functional ecology Industrial ecology Macroecology Microecosystem Natural environment Regime shift Sexecology Systems ecology Urban ecology Theoretical ecology
Outline of ecology

Community ecology

Species abundance distribution

Measurement

See also

References

External links