PITFALL TRAPS DATA BASE

This data base shows the results for invertebrates falling in pitfall traps at the end of June over three successive years. The traps were set at 5m intervals along transect lines running from a lawn into an area of woodland. They were left over a 24h period and the animals were collected identified and counted. The animals were sorted into Families or Classes.

Open the file and save it onto your computer's desktop. Open TrapsDB.xls from your desktop.

The data is arranged by year, team, trap and then each taxon (family or class).
Each time an organism is recorded a P is entered for “present”.

Highlight the cells with the column headings. Go to Data, Filter, and then Auto filter

To verify which are the dominant groups of animals

Click on each column in turn and select P. The totals are given in the bottom left hand corner. After you have finished with a column to display all the data you must go to the filter for that column again and select (All).

To determine how a group is distributed along the transect.

Pick a dominant group. Select P in the filter. Then go to the Traps column and select each trap in turn. Once again the totals are given in the bottom left hand corner of the screen.

Enter the values for each trap in a table under the spread sheet, or open another spread sheet. Then plot a bar chart of the distribution of that species.

To determine how the distribution of a group varies over a space and time

Try the same thing again but this time find out how the numbers caught for the group varied over the three year period. You will  need to filter the group of animals first (select P). Then filter the trap number (1, 2, 3, 4, 5 or 6). Finally, select each year.

The number of teams collecting data varied how are you going to compare them fairly?

Diversity

Inspect the data trap by trap to determine how many different types of groups are represented in each trap each year or over the three years.

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© Paul Billiet 2010