Beta diversity
Encyclopedia
Beta diversity is a measure of biodiversity
which works by comparing the species diversity between ecosystem
s or along environmental gradient
s. This involves comparing the number of taxa that are unique to each of the ecosystems.
It is the rate of change in species composition across habitats or among communities. It gives a quantitative measure of diversity of
communities that experience changing environments.
where, S1= the total number of species recorded in the first community, S2= the total number of species recorded in the second community, and c= the number of species common to both communities.
Sørensen's similarity index
where, S1= the total number of species recorded in the first community, S2= the total number of species recorded in the second community, and c= the number of species common to both communities. The Sørensen index is a very simple measure of beta diversity, ranging from a value of 0 where there is no species overlap between the communities, to a value of 1 when exactly the same species are found in both communities.
where, S= the total number of species recorded in both communities,
=average number of species found within the communities.
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
which works by comparing the species diversity between ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s or along environmental gradient
Environmental gradient
An environmental gradient is a gradual change in abiotic factors through space . Environmental gradients can be related to factors such as altitude, temperature, depth, ocean proximity and soil humidity....
s. This involves comparing the number of taxa that are unique to each of the ecosystems.
It is the rate of change in species composition across habitats or among communities. It gives a quantitative measure of diversity of
communities that experience changing environments.
Absolute value
At its simplest, beta diversity is the change in species composition (i.e. the names of species) between habitats or communities. This can be represented by the following equation:where, S1= the total number of species recorded in the first community, S2= the total number of species recorded in the second community, and c= the number of species common to both communities.
Sørensen's similarity indexSørensen similarity indexThe Sørensen index, also known as Sørensen’s similarity coefficient, is a statistic used for comparing the similarity of two samples. It was developed by the botanist Thorvald Sørensen and published in 1948....
where, S1= the total number of species recorded in the first community, S2= the total number of species recorded in the second community, and c= the number of species common to both communities. The Sørensen index is a very simple measure of beta diversity, ranging from a value of 0 where there is no species overlap between the communities, to a value of 1 when exactly the same species are found in both communities.
Whittaker's measure
where, S= the total number of species recorded in both communities,
=average number of species found within the communities.