Welcome to Community Ecology

1. Welcome to Community Ecology Dr. Mark B. Bush Spring 2006

2. Course Requirements • Lectures and labs are required. Period. • You are required to be professional in your behavior, that means no eating or drinking in class, and be punctual. • No make-up quizzes or exams without physicians note. • This is a 4000 level class…it is much harder than any class you have taken so far….much more is expected of you.

3. Readings • All readings must be read BEFORE class.

4. Keys to success. • 100% attendance. • Good project work. • Doing ALL discussion readings BEFORE the class. • Doing the required readings before quizzes • Don’t sit at the back of the class

5. Grading • 2 midterms (15% each), and 1 cumulative final (30%) will test your detailed knowledge and understanding of the material from lecture and textbook. • Lab will be worth 30% • Sigma Xi grant proposal 10% • Two missed lectures or discussions or 1 missed lab = grade lowered by a half point (e.g. from low b to high c).

6. I can help • I don’t bite, talk to me. • Office or lab: Room 218/220. • If you can, set up an appointment in the Bio office to see me during office hours. • As a last resort email me to set up another time. • mbush@fit.edu

7. Office hours • Tuesday 9 - 11 am • Wednesday 10 - noon • Thursday 1 - 2pm

8. Goal of class • Provide an introduction to theoretical and applied community ecology. • Introduce concepts that are the mainstays of conservation biology. • Develop skills in experimental design and reporting.

9. And now the good news! • These notes and additional readings are available on-line via Blackboard (course documents) • I will continue to put them up so long as YOU attend class.

10. What is community ecology? • The study of the interactions of species and their relationship to the environment. • General Ecology (Bio 3410) introduced population biology…we will build on that basis to consider interactions of suites of species. • Can be approached through mathematical models, experiments, and descriptive investigations.

11. Topics we’ll cover • Niche and guild structure • Succession • Influence of climate • Patterns and measures of diversity • Influence of environmental change

12. Why study community ecology? • Species do not operate in isolation…..to understand any individual species it must be seen in the context of its ecosystem. • Ecosystems do not operate in isolation. Cannot understand coral bleaching without understanding global climate change. • Cannot understand global climate change without understanding carbon flux and transpiration of forest systems.

13. Application of community ecology • How will ecosystems change in the future? • How can conservation designs incorporate global climate change and habitat loss? • To get to these issues we have to understand the process of ecological responses to stimuli…..that is community ecology.

14. Ecology must be based on sound science • Scientific process: • Observation -> hypothesis generation -> experimental observation -> inference -> hypothesis accepted or rejected. • Sounds simple but takes a lot of practice to be good at this.

15. Observation to hypothesis • Science is founded on accurate, unbiased, repeatable observations. • From these observations we construct a hypothesis. • A good hypothesis is consistent with all the data and is testable.

16. What is the hypothesis being tested here? • 30 snakes were starved for a month. Group 1 (n =10) snakes had their eyes covered with an opaque film, Group 2(n = 10) had the nerve receptors from their pits severed, Group 3 (n = 10) had both treatments. Live mice were introduced to their cages. Group 3 fed the most successfully, Group 2 the least successfully. What is wrong with this experiment?

17. What hypotheses can you generate from these data? prey mass number Jaguar Puma (kg) in hunting diet % diet % area Peccary 25 200 60% 10% Agouti 5 100 30% 70% Deer 20 40 10% 20%

18. Testing a hypothesis • A hypothesis must be testable • It should lead to a deeper understanding of the issue, i.e. be non-trivial • Can you prove a hypothesis?

19. NO! You cannot prove a hypothesis!

20. A Theory • There are NO facts in biological science. • There are hypotheses that have been tested and have not been refuted. • A complimentary group of hypotheses form a THEORY. • A theory is science’s most powerful idea, i.e. Theory of Gravity, Theory of Electricity, Theory of Evolution.

21. Experimental design Gaining data to test a hypothesis

22. Simple interactions • So far you have considered one-on-one interactions. • Models, e.g. Lotka-Volterra competition or predation models. • Can also look at environmental variables, e.g. the effect of fire on population size. • Statistical testing: choose the appropriate test from those taught in Biometry. • These relationships form the basis for understanding all ecology.

23. Complex interactions • However, we often have multiple interacting species and other variables (e.g. soil, climate, area), and so it is more complex to evaluate interactions. • Models must include more factors. • Statistical treatment may not be able to test a single variable, but rather help to refine hypotheses.

24. Correlation not causation • Community ecology often deals with correlation not causation. • When studying communities we are often asked: • How similar is this community to that one? • Does factor A correlate with a change in community? • Can we predict what will happen to the community if we change factor A?

25. Why experiment? Diversity • This image plots altitude against plant diversity in the Himalayas. What explains the change in plant diversity? • Altitude and diversity are correlated. You do not know if they are causally connected. • What factor might be causing this change in diversity? Altitude

26. Sigma Xi design • Here are some key pointers to consider as you design any experiment. • When you do your Sigma Xi design be sure to think through all these elements.

27. Identify problem • Your research topic should be based on a rationale. • Research a topic to see what has been done before. Remember a lot of excellent science was done before 1985 and so computer-based search engines may not reveal older work. • Apply the minnow test:- substitute your target organism with a minnow, is this still interesting science? If not, think again. • Take a bite-sized piece of the problem.

28. Essence of good experimental design • Simplicity • Tractability • Controls • Replicates

29. Designing an experiment • Decide if you are going to test for correlation or causality. • Formulate a TESTABLE hypothesis. • Decide what data you need to test the hypothesis. • What data would refute the hypothesis? • Now design an experiment to gather those data.

30. Check your design • Is it realistic to do all you intend? • Is your survey method appropriate? • Have you identified controls? • Have you replicates and are they sufficient for the stats you want to run?