Criteria 1: Diversity

Criteria 1: Diversity

What does this map show?

Richness (S,)

Number of taxa in a planning unit (also referred to as alpha diversity)

Diversity (H')

Shannon Diversity. An index that incorporates the number of species and the evenness of the distribution of individuals across species (we used area of occurrences in a planning unit as our measure of abundance).  The index can increase either by having additional unique species, or by having greater species evenness (Shannon, 1948)

Richness Index (Ii)

An index of species richness which is weighted by individual species’ frequencies of occurrence. Planning units with high Ii values contain many widespread species (Minns, 1987, Chu et al., 2003)

Phylogenetic Diversity (PD)

A measure of diversity based on units of phylogenetic variation (instead of species) (Faith 1992, Faith et al., 2004). For a given faunal group, PD is calculated as the sum of those branch lengths of the phylogenetic tree representing the species occurring in a planning unit.  Areas with high PD may represent centres of current speciation and may be important areas to protect for maintenance of evolutionary processes.  High PD could arise by having a high number of closely related species or by having few species that are phylogenetically divergent from one another. PD incorporates complementarity in that the score contributed by a given taxon in a planning unit depends on how closely it is related to other species present. Moleclular phylogenies are not available for most faunal groups and taxa considered in this report, so we used published phylogenies and assumed equal branch lengths.  The level of taxonomic resolution used to calculate PD varied among faunal groups (order for macroinvertebrates, family-level for fish and waterbirds, and species-level for turtles).

Sample map

Criteria 1: Diversity