- Identify the organism or biological attribute that you plan to study.
- Use your field journal to document observations of your organism or biological attribute along an environmental gradient. Choose at least three locations along the gradient and observe and record any changes in the distribution, abundance, or character of your object of study.
- Think about underlying processes that may cause any patterns that you have observed. Postulate one hypothesis and make one formal prediction based on that hypothesis. Your hypothesis may include the environmental gradient; however, if you come up with a hypothesis that you want to pursue within one part of the gradient or one site, that is acceptable as well.
- Based on your hypothesis and prediction, list one potential response variable and one potential explanatory variable and whether they would be categorical or continuous. Use the experimental design tutorial to help you with this.
Presence of marsh marigold, what affects their growth. Is water depth and/or movement a factor?
Marsh marigold is in one primary location in a few clumps on the storm drainage canal I am studying. These exist only here, the only difference in this spot compared to the others is this spot has water flow coming into the canal. They are in very shallow water among the rocks. The rest of the riparian area along the canal is a bit deeper as far as water depth and has now flow, the water is still.
My hypothesis is marsh marigold is more abundant and does better in areas with water flow and that is shallow. I believe this due to the fact I have only found it in the one area with certain variables present.
Response variable is categorical with logistic regression based on presence/absence data.
What is the effect on water depth/flow of marsh marigold?
This could be hard to study if you only find it in one small area and you have a much larger area where it is not found. In general, it can be hard to figure out why something is only growing in one specific location. You need more replicates to be able to test your hypothesis. Think about how big the area where it is found is and if you could have multiple independent replicates? Independence of your samples could be an issue if there are only a couple of clumps.
I think you should include multiple sites with different depths and water flow to make sure you have a broader comparison of marsh marigold abundance across different environments. You should also take into a count more factors like soil type, how much light there is, nutrients present, wildlife presence, and other plant competition, because those could all influence the distribution and abundance of marsh marigold.