What defines biodiversity at a species level?

Biodiversity at a species level is defined by the variety and abundance of different species within a particular area.

Biodiversity, a contraction of 'biological diversity', refers to all the variety of life that can be found on Earth (plants, animals, fungi and micro-organisms) as well as the communities that they form and the habitats in which they live. At a species level, biodiversity is often measured by two major components: species richness and species evenness.

Species richness refers to the number of different species present in a particular area. This is the simplest measure of biodiversity and it gives equal weight to all species regardless of their abundance. For example, a forest with 100 different species of trees would have a higher species richness than a forest with only 50 different species.

Species evenness, on the other hand, refers to how evenly the individuals in a community are distributed across the different species. For instance, if a forest has 100 trees, and 99 of them are of the same species, while the remaining one is of a different species, then the forest has low species evenness, despite having a species richness of two.

In addition to species richness and evenness, biodiversity at a species level can also be characterised by the genetic diversity within and between species. Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.

Biodiversity at a species level is crucial for the health and resilience of ecosystems. High biodiversity can contribute to the stability of ecosystems, increase their productivity, and enhance their ability to recover from disturbances. It also provides a source of genetic material that can be crucial for the adaptation and survival of species in the face of environmental changes. Therefore, understanding and preserving biodiversity at a species level is of paramount importance for the sustainability of our planet.