Chapter 1 What is Biodiversity?

1. Chapter 1What is Biodiversity? Spiders as Exemplars of the Biodiversity Concept

2. Five forest remnants from a previously contiguous forest.

3. How was the spider community sampled? Are there other spiders present that weren’t collected?

4. Have you sampled enough? The Collector’s Curve Cumulative number of species

5. Summary Table

10. Analyzing Community DiversitySimpson Reciprocal Index, 1/D[Erratum: page 8, line 3; 2s are exponents] D =  pi2 where pi is the fractional abundance of each species Sometimes referred to as “evenness”

11. For Site 1 There are 10 species, each with 5 specimens D =  pi2 Where pi is the fractional abundance of each species 1/D = 1/[ (5/50)2 + +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2 +(0.1)2] 1/D = 10 The higher the value, the more diverse. The maximum value is the number of species present. This indicates an equal number of individuals in each species.

12. Analyzing Community DistinctivenessJaccard Coeffecient of Community Similarity, CCJ • CCJ = c /S • Where • c is the # of species common to both communities • S is the total # of species in both communities • Value ranges from 0 to 1: • 0 indicates no species in common • 1 indicates all species found in both communities

13. CCj estimates

14. For Sites 1 and 2 CCJ = c /S = 4 common/12 total = 0.333