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Introduction

Methods

Background and Design

Data Preperation

Analyses

Results

Discussion

Literature Cited

Data Preperation:

The original data obtained from species level ground beetle identifications was first entered into a relational database within Microsoft Access. The data was checked for consistency and then I proceeded to pool the data to obtain a final flat file for analyses. When pitfall trapping, a total of four different collections are obtained throughout the summer, thus these collections were pooled together to have a single sample for the entire summer. Following this, the replicated transects from within each site were pooled as well in order to avoid problems of pseudo-replication within the data set. The final flat file was then used in analyses.

Data Standardization:

Since pitfall traps experience variable amounts of disturbance from animals throughout the summer, the raw abundances of individual species cannot be compared between sites. Thus it is necessary to standardize the species abundances by the number of days the trap was active. This standardized abundance permits reliable comparisons between treatments. To achieve this standardization I had to enter the number of days for which each trap was active. I then divided the total abundance of each species, at each trap, by the total number of days the trap was active. For a visual representation of the preparation and standardization process click here.

Additional Preperation:

As there is a high potential for error in the automatic query procedures within Microsoft Access, I manually checked all of my queries to ensure that the species data was being pooled properly. This ensured full confidence in the produced flat-file prior to completing any of the statistical analyses. It also assisted me in developing an understanding of the species compositions within my data set and the ability to see which species were most abundant within the study.

Using the flat file I then performed an outlier analysis on both the standardized species abundances, and the sites to assess potential outliers within my data set. The outlier analysis was performed within PC-ORD Version 5.0.

I also prepared a partial data set of the environmental variables along the edge gradient which I had proposed in my original work plan. After spending multiple days entering the data for this section of the project, and making a small dent in the amount required, I elected to omit the environmental data from analysis in this project.