Experimentation

2- Developing an experimental design. How are ecology experiments designed? Your research hypothesis, experiment, and consequently your results have to be related.

Why do we sample the environment? The goal in science is often to try to estimate some parameter of interest. It's impossible to measure every individual of a population of interest. Generally, the more samples you collect, the more confident you can be about the results you find. By taking measurements in several or many study plots (replicating), and averaging your results, you can account for the effect of natural variation (heterogeneity) present in the forest. This natural variation of the environment can be very misleading if you are not aware of it. In general, we will want as large of a sample as possible. This will improve our confidence that the estimate we generate from the sample is close to the actual parameter we are interested in knowing.

It is impossible in nature to find two identical locations for an experiment. If you are conducting an experiment, to avoid the error of overlooking a variation, you need to assign the "treatment" and the "control" randomly. What problems can arise when you design and carry out your experiment? Did you have enough samples? Two or more representatives of each treatment, called replications, are necessary to ensure that you obtain a sufficient sample size and a representative sample size.

Click here to read: Pseudoreplication and the design of ecological field experiments. In this paper, Stuart H. Hurlbert reviews 176 experiments and finds that pseudoreplication occurred in 27% of them.

3- Obtaining evidence by observation and measurement. Your observations must be somehow accountable.

4- Using logic and insight to analyze data. Data analysis is about extracting meaningful information from your dataset using an appropriate tool. Displaying the data in graphical form often helps you to extract meaningful information. However, there is often a great deal of stochasticity (randomness, or noise) in ecological systems, so ecologists often employ tools whose specialty is separating meaning from noise - statistics! How does the use of evidence (data collected and analyzed) help to confirm or disprove your hypothesis? Your qualitative conceptual model may help you understand what your results mean also. Click here to see an example.

5- Interpretation. Why must you coordinate ecological theory and your evidence to develop an explanation for your findings?

Your experiment is an evaluation of how likely your explanation of the pattern or phenomenon is. Therefore, you need to carefully explain how your results mesh with , or contradicts, your previous explanation of ecological theory, and how you can explain the differences.