This document discusses disturbance ecology and different approaches for estimating characteristics of ecological communities, analogous to methods for estimating the number of books in a library. It defines ecological disturbance as discrete events that disrupt populations, communities, and ecosystems. Disturbances are regular, predictable events that species can adapt to, unlike rare disasters. The frequency, location, magnitude, and intensity of a disturbance regime can affect evolutionary adaptations and species diversity within a community.

1. Disturbance Ecology Dr. Mark McGinley Special Topics in Ecology and Biodiversity ISB, UM 2010

2. How Many Books in the Library? How would you try to figure out how many books in the library? Counting is the boring way Are there other approaches we could use to estimate the number of books

3. Is the Library Full? If the library is full then it is relatively easy to determine the number of books in the library.

4. If the library is full Need to know Total length of book shelves Mean width of book # books = total length of book shelves/mean book width

5. What If The Library is Not Full? Then we need to know a different approach, We need to know something about the rate at which books are added and lost from the library

6. How Does This Relate To Ecology? Different approaches to understanding causes of patterns of biodiversity - are communities full of species or are communities not full of species.

7. Equilibrium Approach If communities are full of species, then we can understand biodiversity by understanding the factors that limit the number of species in a community Competition If competition determines community structure then the maximum number of species that can be found in a community is equal to the number of niches.

8. Non-equilibrium Approach Sometimes communities are not full because something stops competitive exclusion from occurring Predation Disturbance

9. Disturbance “ Disturbance” is a word that has a particular meaning in regular usage Typically a “disturbance” is something that disrupts “normal” Yelling and screaming in the library Being told to “shush” at a football game

10. Disturbance Ecologically, disturbance has been defined in different ways by different people. Important to recognize this and always be aware of which definition people are using

11. Disturbance Pickett and White A disturbance is any relatively discrete event in time that disrupts population, community, and ecosystem structure

12. Fire

13. Fire

14. Landslides

15. Hurricanes

16. Hurricanes- Salt Water Damage

17. Tsunami

18. Floods

19. Not Disturbance- Drought

20. Disturbance Disturbances are regular and predictable events in many communities

21. Disturbance vs Disaster Disturbances occur frequently enough that natural selection can occur Thus, many species are “adapted” to disturbances Disasters occur so rarely natural selection has not occurred Species are not adapted to disasters.

22. Disturbance Regime Frequency Location Magnitude Intensity Synergisms

23. Disturbance Regime- Fire Intensity Crown fire vs. ground fire

24. Importance of Disturbance Evolutionary Organisms should have adaptations that allow them to survive or recover from disturbances

25. Serotinous Cones

26. Importance of Disturbance Ecological Disturbance may effect species diversity in a community First person to think about this was Darwin He recognized more species of grasses growing in fields that had been moved for hay than in fields that were unmowed.

27. Competition Between Grasses

28. Connell’s Intermediate Disturbance Hypothesis