Good Prairie, Bad Prairie

How does one know if an ecological restoration area is a good prairie or a bad prairie? And frankly, what is “good” and what is “bad”?

The Floristic Quality Assessment (FQA) and the Floristic Quality Index (FQI) are management tools ecological restorationists use to objectively ascertain and describe the condition of a restoration or remnant area. I thought these terms were the same and were used interchangeably. I decided it was time to figure it out. In my reading and learning, I realize that I had other aspects of this management tool mixed up as well.

The FQA is the overall name for the management tool and its components are the Coefficient of Conservatism (C) and the FQI. Each plant is given a C value and the FQI is figured based on the mean C value multiplied the square root of the total number of species. You can read more details about this calculation here.

Another aspect I struggled to understand was how species richness fit into this equation. I read about using samples and transects and thought they were the measurement of species richness. Instead these are used when the ecological area (prairie/savanna/woods) is too large to inventory; species richness is inherent in the FQI. I pondered this for awhile and it certainly makes sense.

For simplification, I’ll refer to the ecological area as the prairie. If the prairie is degraded the mean C value will be below 5, regardless of what weeds and/or invasives or how many are present. If the prairie was large enough, one could have a portion of it with a large cover of weeds/invasives and still have a high mean C. That value could increase with the removal/diminishing of those weeds/invasives should that area support higher quality (aka higher C value) plants.

When compiling the inventory of our areas, I included a list of the weeds and invasives. Since our management plan addresses these and I know our property well, I did not quantify their amounts. If I were doing the FQA for another area, I would include some guesstimation as to what percentage was which type of weed/invasive. This would be helpful to those creating the management plan and would be helpful for creating a management plan and tracking progress in the future.

Our prairies are planted but our woods are native so our FQA changes on a yearly basis, thankfully for the better! But if the land was in prairie for some years prior and an inventory list was made but no FQA was completed and there were plants that were known to be there and no longer there, it could be documented by making a note on the FQA report.

Now that I understand this better, I’ll be able to add it to my list of management tools with confidence!