Floristic Quality Assessment (FQA) is a tool used to assess an area's ecological integrity based on its plant species composition. Floristic Quality Assessment was originally developed in order to assess the likelihood that impacts to an area "would be irreversible or irretrievable...to make standard comparisons among various open land areas, to set conservation (ethic), conservation priorities, and to monitor site management or habitat restoration, restoration efforts." The concept was developed by Gerould Wilhelm in the 1970s in a report on the natural lands of Kane County, Illinois. In 1979 Wilhelm and Floyd Swink codified this "scoring system" for the 22-county Chicago Region.

Coefficient of conservatism

Each plant species in a region is assigned a coefficient of conservatism, also known as a C-value, ranging between 0 and 10. A plant species with a higher score (e.g. 10) has a ''lower'' tolerance to environmental degradation such as overgrazing or land development, development and therefore is naturally restricted to undisturbed, remnant natural area, remnant habitats. Non-native plants are either assigned a C-value of 0 or are excluded from assessments. In the Chicago Region, 84% of the native plant species have a C-value of 4 or greater. Plants with a C-value of 4 or greater rarely naturally move from a remnant area to surrounding degraded land. For example, the federally Endangered species, endangered ''Dalea foliosa'' has a C-value of 10. C-values are assigned within specific ecological and geographic regions by botanist, botanical experts familiar with the species' autecology within the respective regions. , there were more than 50 different FQA databases ranging from the Gulf Coastal Plain to western Washington (state), Washington, though most databases represented regions in the eastern and central United States and Canada. The mean C-value ( \bar) is calculated based on an inventory of plants. An area with a native mean C-value of 3.5 or higher likely has "sufficient floristic quality to be of at least marginal natural area quality." Remnant natural areas with mean C-values of 4.0 or greater are environmental mitigation, unmitigable.

Floristic Quality Index

The Floristic Quality Index (FQI, or Rating Index according to Swink and Wilhelm) is calculated by multiplying the mean C value by the square root of the total number of species: \bar\sqrt For example, the FQI fo
Nelson Lake Marsh
was 78 in 1994 and that for Russell R. Kirt Prairie was about 30 in 1999.


{{Reflist, refs= {{cite book , last1=Wilhelm , first1=Gerould , last2=Rericha , first2=Laura , author-link2=Laura Rericha , date=2017 , title=Flora of the Chicago Region: A Floristic and Ecological Synthesis {{cite report , first1=Gerould , last1=Wilhelm , author-link1=Gerould Wilhelm , first2=Linda , last2=Masters , date=June 1995 , title=Floristic Quality Assessment in the Chicago Region and Application Computer Programs , publisher=The Morton Arboretum {{cite journal , last1=Freyman , first1=William A. , last2=Master , first2=Linda A. , last3=Packard , first3=Stephen , date=2016 , title=The Universal Floristic Quality Assessment (FQA) Calculator: an online tool for ecological assessment and monitoring , journal=Methods in Ecology and Evolution , volume=7 , issue= 3, pages=380–383 , doi=10.1111/2041-210X.12491 , doi-access=free {{cite journal , last1=Matthews , first1=Jeffrey W. , last2=Spyreas , first2=Greg , last3=Long , first3=Colleen M. , title=A null model test of Floristic Quality Assessment: Are plant species' Coefficients of Conservatism valid? , journal=Ecological Indicators , date=May 2015 , volume=52 , pages=1–7 , doi=10.1016/j.ecolind.2014.11.017 {{cite book , last1=Swink , first1=Floyd , last2=Wilhelm , first2=Gerould , date=1979 , title=Plants of the Chicago Region, 3rd Edition {{cite book , last1=Swink , first1=Floyd , author-link1=Floyd Swink , last2=Wilhelm , first2=Gerould , date=1994 , title=Plants of the Chicago Region, 4th Edition {{cite report , first1=Gerould S. , last1=Wilhelm , date=1977 , title=Ecological assessment of open land areas in Kane County, Illinois , publisher=Kane County Urban Development Division

External links

Universal FQA
Biodiversity Environmental conservation Community ecology Measurement of biodiversity Index numbers Summary statistics for categorical data