In ecology, alpha diversity (α-diversity) is the mean species diversity in sites or habitats at a local scale. The term was introduced by R. H. Whittaker together with the terms beta diversity (β-diversity) and gamma diversity (γ-diversity). Whittaker's idea was that the total species diversity in a landscape (gamma diversity) is determined by two different things, the mean species ...
The terms alpha, beta, and gamma diversity were all introduced by R. H. Whittaker to describe the spatial component of biodiversity. Imagine that you have a landscape containing of a number of separate sites and habitats. Alpha diversity is just the diversity of each site (local species pool).
Alpha diversity refers to the average species diversity in a habitat or specific area. Alpha diversity is a local measure. Beta diversity refers to the ratio between local or alpha diversity and regional diversity. This is the diversity of species between two habitats or regions. It is calculated by the following equation:
Alpha and beta diversity. Alpha diversity. Species richness (OTU count) "How many?" How many different species could be detected in a microbial ecosystem? Species richness is the number of different species in a sample. Practically, we count the number of distinguishable taxa (OTU's) in each sample → QIIME OTU counts.
Alpha diversity was defined by Whittaker (1972) as the species richness of a place. However, the practical development of this concept led to redefine the alpha diversity on the basis of the ...
For example in the figure below, Alpha Diversity of Site A = 7 species, Site B = 5 species, Site C = 7 species. Beta Diversity = expression of diversity between habitats. In the example below, the greatest Beta Diversity is observed between Site A and C with 10 species that differ between them and only 2 species in common.
In ecology, beta diversity (β-diversity or true beta diversity) is the ratio between regional and local species diversity.The term was introduced by R. H. Whittaker together with the terms alpha diversity (α-diversity) and gamma diversity (γ-diversity). The idea was that the total species diversity in a landscape (γ) is determined by two different things, the mean species diversity at the ...
\n Whittaker (1972) described three\n\tterms for measuring biodiversity over spatial scales: alpha,\n\tbeta, and gamma diversity. Alpha\n\tdiversity refers to the diversity within a particular\n\tarea or ecosystem, and is usually expressed by the number of\n\tspecies (i.e., species\n\trichness) in that ecosystem.
Calculating alpha diversity. Suppose species diversity is equated with the effective number of species, and alpha diversity with the mean species diversity per subunit. Then alpha diversity can be calculated in two different ways that give the same result.
alpha_diversity.py – Calculate alpha diversity on each sample in an otu table, using a variety of alpha diversity metrics¶. Description: This script calculates alpha diversity, or within-sample diversity, using an OTU table. The QIIME pipeline allows users to conveniently calculate more than two dozen different diversity metrics.