alphadiversiteit

Alphadiversiteit (Dutch for alpha diversity) refers to the diversity of species within a particular area or ecosystem, such as a plot of land, a pond, or a sampling site. It is a local measure of biodiversity and contrasts with beta diversity (compositional change between sites) and gamma diversity (total diversity at regional scale). The concept was introduced by Robert Whittaker in the 1960s, who proposed alpha, beta and gamma as components of biodiversity.

Measuring alphadiversiteit typically uses species richness (the number of species, S) as a simple metric, but more informative indices incorporate both richness and evenness, such as the Shannon index (H') and Simpson's index (D). Evenness describes how evenly individuals are distributed among species. In practice, researchers may use rarefaction or Hill numbers to compare communities with unequal sampling effort.

Alphadiversiteit is influenced by factors such as habitat size and quality, productivity, structural complexity, disturbance regime, and spatial scale. It is sensitive to sampling methods and effort, making standardization important. In microbial and soil ecology, alphadiversiteit is used to describe the richness and distribution of microbial taxa within a sample.

Applications include evaluating habitat health, monitoring environmental change, and informing conservation planning. Limitations include dependence on sampling completeness, detection probabilities, and scale dependence; therefore, alphadiversiteit is most informative when interpreted alongside beta and gamma diversity and across comparable sampling designs.