1. Community Attributes Kenneth M. Klemow, Ph.D. Wilkes University Kenneth M. Klemow, Ph.D. Wilkes University

2. Communities defined  Assemblage of interacting populations in an area.  Typically categorized according to trophic level / functional group  Size of communities varies  Depends on size of species and degree of mobility  For vegetation, concept of “stand” important  Have important attributes  Assemblage of interacting populations in an area.  Typically categorized according to trophic level / functional group  Size of communities varies  Depends on size of species and degree of mobility  For vegetation, concept of “stand” important  Have important attributes

3. Species composition  List of species in an area.  Can range from monocultures to assemblages of hundreds of species.  Floras and faunas  List of species in an area.  Can range from monocultures to assemblages of hundreds of species.  Floras and faunas www.dep.state.fl.us

4. Species area curve  Look at accumulation of species with increasing number of plots sampled  Get saturation effect  Used in conservation biology to predict species loss with habitat loss  Look at accumulation of species with increasing number of plots sampled  Get saturation effect  Used in conservation biology to predict species loss with habitat loss www.scieng.ed.ac.uk

5. Density  Number of individuals in an area  Each broad taxonomic group presents own challenges  Plants - ramets vs genets  Animals - deal with mobility  Fungi - What’s an individual?  Calculate relative density  Number of individuals in an area  Each broad taxonomic group presents own challenges  Plants - ramets vs genets  Animals - deal with mobility  Fungi - What’s an individual?  Calculate relative density

6. Calculating relative density Species DensityRel. Dens. A40037.0 B605.6 C37034.3 D807.4 E17015.7 Total 1080 100.0

7. Frequency  Proportion of times that a species will appear in a defined number of samples.

8. SpeciesFrequencyRel. Freq. Total10

9. Concepts relating to frequency  Commonness vs rarity  Common: >60%  Rare: <20%  Raunkiaer’s “law”  A= 0-20%  B= 20-40%  C= 40-60%  D= 60-80%  E= 80-100%  A>B>C=D<E  Commonness vs rarity  Common: >60%  Rare: <20%  Raunkiaer’s “law”  A= 0-20%  B= 20-40%  C= 40-60%  D= 60-80%  E= 80-100%  A>B>C=D<E ABCDE

10. Abundance patterns in communities  Counts of species abundance or frequencies often yield interesting patterns.

11. Now sort the data  Order of decreasing abundance

12. And categorize to yield frequency distribution  Place into categories of 25

13. Now create a histogram

14. Now set up categories to follow geometric progression:  0-1  1-2  2-4  4-8  8-16  16-32  32-64  64-128  128-256  0-1  1-2  2-4  4-8  8-16  16-32  32-64  64-128  128-256

15. Now create a new histogram

16. Ecologists have found lognormal distribution in nature

17. Diversity  Measure of heterogeneity among species in a community  Has two components:  Richness  Evenness  Measure of heterogeneity among species in a community  Has two components:  Richness  Evenness www.ipgri.cgiar.org

18. Measures of Diversity  Species richness - S  Shannon-Weiner index  H’ = -  (p i x ln p i )  Accounts for both richness and evenness  Evenness  J = H’/ln S  Simpson’s index   (p i )  Accounts for dominance  Inverse Simpson’s index  1/  (p i )  Accounts for diversity  Species richness - S  Shannon-Weiner index  H’ = -  (p i x ln p i )  Accounts for both richness and evenness  Evenness  J = H’/ln S  Simpson’s index   (p i )  Accounts for dominance  Inverse Simpson’s index  1/  (p i )  Accounts for diversity

19. Look more closely at Shannon- Weiner index

20. Stress-subsidy relationships important StressSubsidy H’

21.  diversity   diversity - within specific community or habitat   diversity - across several communities along a gradient   diversity - across range of habitats in landscape or geographic area   diversity - within specific community or habitat   diversity - across several communities along a gradient   diversity - across range of habitats in landscape or geographic area

22. Dominance  Degree to which one species intercepts resources and regulates community function  Typically related to biomass  Concept of keystone species  Degree to which one species intercepts resources and regulates community function  Typically related to biomass  Concept of keystone species geoggeol.wku.edu

23. Stability  Ability of a community to remain constant over time, especially in face of perturbation.  Two components:  Resistance  Resilience  Ability of a community to remain constant over time, especially in face of perturbation.  Two components:  Resistance  Resilience www.epa.gov/nps/