Species Richness and Diversity 1

Species Richness vs Species Diversity Does species richness tell the whole story? Which community is more species rich? More species diverse? 2

Use of Simpson’s D () Taxon  pi pi2 Frog Black Snake Spotted Snake A measure of the probability that two individuals sampled randomly from a collection of S species (a community) will be the same species. Unbiased estimate Even Distribution Frog Dominated Taxon pi pi2 Frog 0.14 0.02 0.57 0.32 Black Snake 0.07 0.005 Spotted Snake Salamander Toad Snapping Turtle Box Turtle  0.35 Simplified estimate 3

Use of Simpson’s D () Taxon  pi pi2 Frog Black Snake Spotted Snake A measure of the probability that two individuals sampled randomly from a collection of S species (a community) will be the same species. IB Biology Guide, p. 131 Even Distribution Frog Dominated Taxon pi pi2 Frog 0.14 0.02 0.57 0.32 Black Snake 0.07 0.005 Spotted Snake Salamander Toad Snapping Turtle Box Turtle  0.35 I have never encountered the “Simpson’s reciprocal index of diversity” in published research. Unbiased estimate Simplified estimate 4

Shannon’s H' Contribution to Diversity A measure of the average “uncertainty” in predicting to what species an individual chosen at random from a collection of S species and N individuals will belong. 5

Shannon’s H' Contribution to Diversity (From Hayek and Buzas Surveying Natural Populations) As the proportion of an individual species in a community increases, its contribution to the diversity index, piln(pi), reaches a maximum at a proportion of 0.368. The Palm Warbler and Yellow-rumped Warbler have nearly equal contributions to the overall diversity index. 6

Shannon’s H' Contribution to Diversity (From Hayek and Buzas Surveying Natural Populations) 7

Use of Shannon’s H’: Strode (2009) 8

Use of Shannon’s H’: Strode (2009)