Life’s Richness Pageant or Summary Measures of Diversity

Species Richness: A simple measure A count of species in a collection

Richness is simple but has multiple ways it can be measured. Method 1: a.) Overlay a set of range on top of one another b.) Overlay a grid of certain resolution (must be chosen carefully) c.) Count observed number of species in each grid cell

One can also sample species discovered in a set of surveys Method 2: a.) Sample species in a quadrat (multiple methods) b.) Count number of species per quadrat c.) Problems with sampling! (more if people are interested)

Comparison of richness based on Breeding Bird Survey and bird range maps (Hurlbert and White, 2005)

WHAT DOES PHYLOGENY HAVE TO DO WITH SPECIES RICHNESS?

(what if you have six closely related species in quadrat A Area A has species 16-25 (10 total) and Area B has 2-4, 8-10, 12-15. Which is more diverse? One measure: Sum the branch lengths along the minimum spanning path (what if you have six closely related species in quadrat A and 6 wildly unrelated species in quadrat B? Which is more important in a conservation context?)

Diversity is a measure of both richness (S) and species evenness (defined as the ratio of H (the Shannon-Weaver diversity index H=−∑ρiln(ρi)) divided by Hmax (or Ln(S)). WHICH WOODLAND, A or B, is more diverse? More rich?

ENDEMISM Are there geographic areas where there are more narrow range taxa than in adjacent areas? How to measure? Challenging! How endemic is endemic (less than 4 grid cells? 8?) Weighted endemism: calculates a weight per species (large ranging specie have low scores, the narrowest the highest). Sum the weights of all species in a cell. Corrected weighted endemism: divides WE by S (why? Think about probability!   c

Uses information about ranges of sister taxa to determine PE PHYLOGENETIC ENDEMISM takes into account those taxa that are most evolutionary distinctive in measure Uses information about ranges of sister taxa to determine PE

Phylogenetic diversity figures in the PE calculation Phylogenetic diversity figures in the PE calculation. The idea is that long branched endemics that are related generate high PE, while short branched don’t as much. Not worried about calc. General idea. See: Biodiverse software

Inventory Completeness and Effort Needed (how does GBIF data right now relate to what we know about diversity from range maps?

Inventory Completeness and effort needed (how does GBIF data right now relate to what we know about diversity from range maps?) EEK rs = 0.02 (N = 14,812).

Can we predict how many more datasets are needed to get to near-complete coverage? YES! Extrapolation from current relationship between number of collections and proportional richness.