Floristic Quality Assessment

Northern Rocky Mountain grassland in the Blue Mountains
Northern Rocky Mountain grassland in the Blue Mountains

Ecological indicators have been widely promoted among a number of agencies, conservation organizations, and researchers as a means of guiding conservation and management decisions such as choosing sites for conservation, monitoring restoration progress, setting restoration performance goals, and tracking trends in ecological condition over time. The distribution of vegetation across the landscape is a result of numerous abiotic and biotic processes and interactions including past and present climate, hydrology, soils, aspect, competition, and natural or anthropogenic disturbances. Spatial and temporal human disturbances have a strong role in determining which plant species are able to survive and/or compete in a particular site. As such, vegetation is known to be a sensitive measure of human impacts including hydrological alterations, sedimentation, vegetation removal, physical disturbance, watershed development, mining, presence of invasive plants, and nutrient enrichment. Thus, the composition of vegetation growing at a particular site integrates spatial and temporal impacts and can serve as an indicator of ecological integrity or condition.
The Floristic Quality Assessment (FQA) method uses vegetation composition as a means of assessing ecological condition. FQA focuses particularly on the concept of plant ‘conservatism’ as an indicator of the ecological quality of a given site. Conservative species are defined as being restricted to intact ecosystems where ecological processes, functions, composition, and structure have not been (or minimally so) degraded/modified by human stressors. Non-conservative or generalist species are those which have a broader ecological niche and thus don’t show fidelity to a specific set of environmental parameters. FQA results provide numeric values which can be used to conduct ecological monitoring and assessment of Washington vegetation communities/ecosystems. Specifically, FQA can assist in prioritizing vegetation communities/ecosystems for protection, restoration, or management efforts, and to monitor the effectiveness of these actions.
FQA refers to multiple indices many of which share a common variable—the coefficient of conservatism value (C-value) of native species—and are used to assess the quality of a particular habitat or site. C values reflect the relative conservatism of a given species by assigning it a value between 0-10 (10 being the most conservative). Our program convened a group of experts to assign C-values for all native plant species occurring in Washington.
FQA provides a unique approach to ecological monitoring and assessment which moves beyond simple measures of species richness and abundance and provides an estimate of the quality of native plants at a site. FQA-based indices have been rigorously tested in other regions of the United States and have been shown to be very sensitive indicators of ecological condition.

What is FQA used for?

FQA integrates the overall conservatism of a site’s flora into an indicator of ecological integrity that can be utilized for numerous objectives including monitoring, conservation prioritization, and setting restoration benchmarks.
Species lists are compiled for a given area (defined by project objectives) and the C-values associated with those species are then used to calculate an index value. Many different conservatism-based indices have been constructed. The most basic is the average C value of native species occurring in a given area. The Floristic Quality Index (FQI) is another commonly used index that incorporates species richness into the calculation. Numerous variations of both these indices have been employed. Determining which index to use is a function of project objectives and index performance in a given ecosystem type.
Below are some examples of the type of projects that FQA-based indices could be applied toward:
  • Identifying conservation priorities.
  • Identifying reference conditions for specific ecosystem types.
  • Monitoring and evaluating the short- and long-term performance of ecosystem restoration and enhancement projects.
  • Monitoring and evaluating the long term effectiveness of ecosystem protection projects.
  • Monitoring and evaluating the effectiveness of ecosystem management practices (i.e. water management, weed control, buffers, etc.).
  • Method for prioritizing ecosystem restoration and protection projects.
  • Regulatory programs such as wetland mitigation, Section 404 permitting, critical areas ordinances, etc.
FQA values can also be incorporated into Ecological Integrity Assessments (EIA) as a vegetation metric.

FQA Calculators

Our program has also developed Microsoft Excel-based calculators which include the final FQA databases for western and eastern Washington (see below). The calculators will automatically compute index values for a given dataset. Many different indices are calculated including conservatism-based indices as well as more commonly used metrics such as % non-natives, % annuals, etc. Instructions are included within the calculator and report.
An alternative option is to use the Universal Floristic Quality Assessment Calculator which is an open source project developed by Openlands, a conservation organization based in the Midwest.  The Universal FQA calculator is free for any user, although registration is required. The user can enter data into either a site inventory/relevé plot or transect calculator.  Assessment results can be downloaded and saved for private or public viewing on the Universal FQA website.
Note: Please email Joe Rocchio if you find or suspect any errors in the calculator. Also, please check this website regularly for updates to the calculators.

Relevant technical resources: