Relative species abundance
Relative species abundance is a key concept in ecology that refers to the population of a particular species in relation to the populations of other species within the same ecosystem. It serves as an important measure of biodiversity, indicating the variety and balance of life forms in a specific area. Healthy ecosystems typically exhibit high biodiversity, which contributes to their resilience, productivity, and ability to recover from disturbances. However, measuring relative species abundance can be complex and resource-intensive, often affected by factors like seasonal migrations and human impacts on the environment, such as habitat destruction and resource exploitation.
Researchers can gain insights into ecological dynamics by tracking relative species abundance over time, revealing patterns such as competition among species or changes in population dynamics due to environmental pressures. Understanding these relationships helps scientists assess the health of ecosystems and the effectiveness of conservation efforts. By comparing data from different regions, ecologists can explore how variations in species populations reflect broader ecological interactions and the influence of apex predators on food webs. Ultimately, relative species abundance is crucial for understanding biodiversity and its role in sustaining the balance of life on Earth.
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Relative species abundance
Relative species abundance refers to the population of one species in proportion to the population of other species in an ecosystem. Relative species abundance is an important measure of biodiversity, which is the number of species found in a specific region. Healthy ecosystems tend to have more biodiversity than regions with many threatened or endangered species.
In some cases, calculating relative species abundance is challenging for scientists. The process of studying a region well enough to achieve accurate counts of the plants and animals inhabiting may be labor- or cost-prohibitive. This process is sometimes further complicated by seasonal migrations. However, once conducted, studies of relative species abundance can provide scientists with valuable insight into the inner workings of ecosystems. For example, by studying the relative species abundance of the same ecosystem over time, scientists might note how an increase in the population of one species might lead to a decrease in the population of another species. They might then investigate whether this is because of increased competition, predation, or other causes. Scientists might also compare data collected from various ecosystems, noting how the populations of species changes between regions.
Background
Biodiversity refers to the large variety of life on Earth. All healthy ecosystems contain a multitude of species. Some of these species are healthy, having adapted to the changing world. Others, however, have a population that is declining until the species are threatened or endangered. Many threatened or endangered species in an area is often an indicator of an unhealthy ecosystem.
Biodiversity significantly benefits healthy ecosystems. It makes ecosystems more productive, allows a larger number of plants and crops to be supported in an area, and contributes to climate stability. It can also help regions more quickly recover from natural disasters, make ecosystems more resistant to the effects of pollution, and increase their visual appeal.
Unfortunately, many ecosystems are harmed by the presence of humans. Biodiversity tends to exist in a delicate balance, and people tend to have an immediate and drastic impact on their surroundings. For this reason, the most common threats to biodiversity within an ecosystem are the growth of human populations and the overuse of natural resources.
When people move into a region, either to live or harvest natural resources, they alter the landscape. In many cases, it results in deforestation, which destroys the habitat of naturally occurring species. While some bird species adapt well to an urban environment, other animal species cannot adapt. They become endangered threatened, or extinct.
Biodiversity can also be threatened by the addition of new species into an established ecosystem. While this initially increases biodiversity, a new, non-native species might quickly outcompete native species for limited resources and, if considered an invasive species, can wreak havoc on the ecosystem. Because of this new competition, the native species may decline in number, eventually becoming extinct.
Overview
Relative species abundance is one measure of biodiversity. It refers to the population of a species in comparison to other species in the same ecosystem. In some cases, relative species abundance may be measured between species in the same trophic level instead of the same ecosystem. A trophic level is a position in a food web, which shows a succession of organisms that consume one another. For example, a plant has a low trophic level, while an apex predator like a tiger has a high trophic level or position within the food web. Areas with high levels of biodiversity typically have more complicated food webs than those with limited biodiversity.
In many cases, collecting data on the relative species abundance of a particular region is difficult. The relative abundance of any given species is affected by both large- and small-scale dynamics. These include many difficult-to-analyze factors, such as the existence of nearby protected areas and metapopulation management, which is the movement of individual species into or out of an area to ensure the survival of a species. Conservation efforts, or the lack of, also affect relative species abundance. Furthermore, establishing how such factors are influencing the populations of local species is often costly and labor-intensive.
For these reasons, researchers have searched for simpler, more cost-effective methods of calculating relative species abundance, such as extrapolating larger numbers from a smaller data set, a statistical process known as bootstrapping.
Knowing the abundance of the various species within an ecosystem gives scientists a clearer picture of how competition and predation are affecting the area. It might also show scientists how individual species relate within a given community and whether an increase in the population of one species might be linked to a decrease in the population of other species. Scientists may learn how the removal of a single species from an established ecosystem has influenced the food web.
Given enough data, scientists can compare the differences between the relative species abundance of multiple ecosystems. If these ecosystems contain similarities, it might allow scientists to study how the variations between them influence specific species. For example, if two ecosystems contain similar species through most levels of the food web but have different apex predators, scientists might be able to study how a kind of apex predator affects the relative species abundance throughout a food chain.
Bibliography
Hu, Lei, et al. “Relative Species Abundance Successfully Predicts Nestedness and Interaction Frequency of Monthly Pollination Networks in an Alpine Meadow.” PLOS One, 2019, www.researchgate.net/publication/230094812‗Methods‗of‗studying‗the‗distribution‗diversity‗and‗abundance‗of‗birds‗in‗East‗Africa‗-‗Some‗quantitative‗approaches. Accessed 10 Sept. 2020.
Pomeroy, Derek. “Methods of Studying the Distribution, Diversity, and Abundance of Birds in East Africa – Some Quantitative Approaches.” African Journal of Ecology,www.researchgate.net/publication/230094812‗Methods‗of‗studying‗the‗distribution‗diversity‗and‗abundance‗of‗birds‗in‗East‗Africa‗-‗Some‗quantitative‗approaches. Accessed 10 Sept. 2020.
Reitan, Trond, Torbjorn, H. Ergon, and Lee Hsiang Liow. "Relative Species Abundance and Population Densities of the Past: Developing Multispecies Occupancy Models for Fossil Data." Paleobiology, vol. 49, no. 2, 2023, pp. 23-38, doi:10.1017/pab.2022.17. Accessed 25 Nov. 2024.
“The Importance of Biodiversity.” NASA, ete.cet.edu/gcc/?/biodiversity‗importance/. Accessed 10 Sept. 2020.
“Threats to Biodiversity.” Lumen Learning, ete.cet.edu/gcc/?/biodiversity‗importance/. Accessed 10 Sept. 2020.
Verberk, Wilco. “Explaining General Patterns in Species Abundance and Distributions.” Nature.com, 2011, ete.cet.edu/gcc/?/biodiversity‗importance/. Accessed 10 Sept. 2020.
Volkov, Igor, et al. “Patterns of Relative Species Abundance in Rainforests and Coral Reefs.” Smithsonian, www.researchgate.net/publication/230094812‗Methods‗of‗studying‗the‗distribution‗diversity‗and‗abundance‗of‗birds‗in‗East‗Africa‗-‗Some‗quantitative‗approaches. Accessed 10 Sept. 2020.
“What Is Biodiversity?” American Museum of Natural History, www.amnh.org/research/center-for-biodiversity-conservation/about-the-cbc/what-is-biodiversity. Accessed 10 Sept. 2020.
Yin, Deyi. “A Simple Method for Estimating Species Abundance from Occurrence Maps.” Methods in Ecology and Evolution, 2014, www.researchgate.net/publication/230094812‗Methods‗of‗studying‗the‗distribution‗diversity‗and‗abundance‗of‗birds‗in‗East‗Africa‗-‗Some‗quantitative‗approaches. Accessed 10 Sept. 2020.