Floristic Quality Assessment Index





Restoration Decisions: (and theory)


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Created by:

Abby Rokosch
Jessen Book
Siobhan Fennessy

The Floristic Quality Assessment Index (index of conservatism)

The FQAI was developed for the northern Ohio region as a tool to assess the nativeness of an area based on the presence of conservative species (Andreas, 1995). The FQAI index reflects numerically the impact of human disturbance by taking into account the presence of alien taxa (Andreas, 1995).

To determine the FQAI of a particular wetland site, you must first identify every plant species in the wetland as complete as possible. If you are unsure of an identification, collect sample ID's of your unknown plant and bring them back to the lab for further analysis. After all the plants have been identified (to the species), a coefficient of conservatism is assigned according to the plants ability to tolerate disturbance (i.e. hydrological alteration, high nutrient levels, degraded soil conditions). Below is a table that describes how each plant is assigned this number. The numbers for individual plant species can be obtained using the manual produced by the Army Corps of Engineers (Andreas, 1995).

Coefficient of conservatism Description of plants under this category
0 Alien, or non-native taxa
1-3 Taxa that are widespread and are not an indicator of a particular community type
4-6 Taxa that show an advanced phase of succession of some native community
7-8 Taxa in plant communities in an advances successional stage but are moderately tolerant of disturbances
9-10 Taxa with high degrees of tolerance to a narrow range of ecological parameters

To obtain the FQAI index, the coefficient of conservation into a mathematical equation:

I= R/ sqrt. N

Where: I= FQAI index

R= The sum of valuation coefficients for all plants recorded in the area

N= The number of different native species recorded

The FQAI is a relatively recent tool used to assess the impact of disturbance on natural vegetation. More research needs to be done in order to accurately determine if the FQAI index can measure the functions of an ecosystem as well the status of its plant communities. In research done by Lopez and Fennessy (unpublished data) the mean FQAI scores of the wetlands were typically higher at sites that were located within forested landscapes and that had buffer areas around surrounding them. More research needs to be done in order to correlate the FQAI with other ecological measurements such as buffer zones, location within the landscape, and hydrology. The FQAI is thought to reflect the degree of human-caused disturbance to an area by accounting for the presence of native species, as well as non-native taxa (Fennessy, pers. comm). If the FQAI can be directly correlated to measuring ecosystem functions then it could prove to be a very efficient tool to assess wetland ecosystems for restoration and mitigation.

For an example of what a typical Ohio wetland's FQAI would look like, click here!!