Species Abundance and Diversity

1
Chapter 16

• Species Abundance and Diversity

2
Community

• An association of interacting species inhabiting
  some defined area
• A collection of populations

3
Species Abundance
Most species are moderately abundant, few are
extremely rare or very abundant
4
Species Diversity
Species diversity includes richness and evenness
5
Shannon-Wiener Diversity Index
6
(No Transcript)
7
Species Diversity
Rank Abundance Curves indicate the diversity of a
community
8
Environmental Complexity
Structural richness in one component of a
community can influence the diversity in another
component, this phenomenon is known as
environmental complexity
9
Environmental Complexity
Abiotic structural components can also
influence the diversity of a community
10
Environmental Complexity Nutrients
Increased levels of nutrients can lead to a
decline in species richness How?..
11
Disturbance and Diversity
The Intermediate Disturbance Hypothesis suggests
that diversity will be greatest at moderate
levels of disturbance Why?.
12
Disturbance and Diversity
Disturbance by prairie dogs allows for the
survival of various plant species at different
places in the ecosystem What patterns would you
predict?
13
Disturbance and Diversity
The data from the prairie dog ecosystem supports
the intermediate disturbance hypothesis
14
Human-Disturbance
15
Summary

• Most species are moderately abundant
• Species Diversity
• Environmental Complexity
• Disturbance and Diversity