The kinds of questions found below help us to understand what factors may influence populations of organisms.  In the gall insect database, we have data on the abundance of galls on Canada Goldenrod from five years, in ungrazed watersheds burned at 1, 4, 10, or 20 year intervals, and ranging from 1 to 18 years since their last burn. This database can be used to examine the effects of fire frequency, time since fire, year of sampling, and sampling site (or ‘watershed’) on gall insect populations. 

This gall dataset is from the LTER research files.  Go to the gall insect trail for details about the life history of Canada Goldenrod and the gall insects which occur on this common tallgrass prairie forb.  The database generated by students is at  Galls in Hulbert Fire Demonstration Plots.  

1. What is the average number of galls in each burn treatment?   

2. What is the density of galls in each burn treatment?    

3. What is the density of galls in each sampling year?      

4. How is the density of galls affected by the length of time (in years) since a fire last occurred?

5. What is the density of galls in each four-year burn treatment watershed?   

6. What is the density of galls in each four-year burn treatment watershed in each sampling year?