Lecture 4/5: measuring biodiversity

Index

an indicator (AKA a metric). This is unitless and is not reliant on measurement of abundance.

the three levels of biodiversity

- alpha diversity

- beta diversity

- gamma diversity

Alpha diversity

a measurement of two attributes: species richness and species evenness. It cannot tell us the relative abundance of individual species in a community. It is often measured by the Shannon index (H)

species richness

the biodiversity, or number of different species in a community

species evenness

the equal distribution of individuals among the different species in the community

beta diversity

measures the diversity of species among communities and rate of change in species across a landscape (looks at multiple communities, not just one location). In the simplest cases, this diversity index = 0 because species do not change in composition. It can also be used to measure non-environmental gradients and measure how species are gained or lost relative to other factors