Floristic Quality Index Research Articles

Collaborate in conservation: A method for volunteer-scientist teams to monitor plant community composition long-term in a private old-growth forest

AbstractTo date, most studies on the management of invasive species have been done in nature reserves or national parks. Few published studies demonstrate how scientists and local communities might collaborate to develop science-based management programs in private forests. We present an example of such collaboration. The Congregational Summer Assembly (CSA) is a mixture of common and privately owned lots within old-growth beech-maple forest in Lower Michigan. The community is trying to conserve the forest and, thus, is interested in ecological variables that should be considered when designing a long-term ecosystem based management plan.In this base-line study we developed methods for volunteer-scientist teams to monitor 1) the abundance of established invasive species, 2) native species abundance, 3) local environmental conditions and 4) impacts of anthropogenic disturbances on the forest community composition. In July 2009 we constructed 30 permanent plots (20 m x 20 m), within which we counted and identified to species adult and juvenile trees. We counted and identified to species herbaceous plants and tree seedlings in five 2 m x 2 m quadrats nested within each plot. We measured environmental variables (% canopy, % bare soil, % woody debris and distance from road or building) in each quadrat.The CSA forest is under stress from anthropogenic disturbance and invasive species. Long-term monitoring of forest community composition could augment the efficacy of efforts to control invasive species at the CSA. The floristic quality index value (FQI), a unitless calculation of species per area, calculated for the CSA is 30 (based on 1.2-ha). FQI values calculated for the CSA in 2009 can be compared with those measured in later years to evaluate whether the plant community composition improves over time with management.Of 69 species found in plots, 9 were non-native, 3 of which were invasive. Invasive garlic mustard (Alliaria petiolata) and myrtle (Vinca minor) were the dominant understory species. Garlic mustard remains the priority for eradication efforts. With the exception of garlic mustard no invasive species were found in plots further than 20 m from roads and buildings. A volunteer-based monitoring program for early detection of “founder” populations of invasive species could be effective in controlling invasive species. The CSA acquired funds for the summer of 2010 to build demonstration plots to educate the community on invasive species removal. This study provides a template for scientists to collaborate with private communities interested in science-based management programs that promote conservation.

Collaborate in conservation: A method for volunteer-scientist teams to monitor plant community composition long-term in a private old-growth forest

To date, most studies on the management of invasive species have been done in nature reserves or national parks. Few published studies demonstrate how scientists and local communities might collaborate to develop science-based management programs in private forests. We present an example of such collaboration. The Congregational Summer Assembly (CSA) is a mixture of common and privately owned lots within old-growth beech-maple forest in Lower Michigan. The community is trying to conserve the forest and, thus, is interested in ecological variables that should be considered when designing a long-term ecosystem based management plan.In this base-line study we developed methods for volunteer-scientist teams to monitor 1) the abundance of established invasive species, 2) native species abundance, 3) local environmental conditions and 4) impacts of anthropogenic disturbances on the forest community composition. In July 2009 we constructed 30 permanent plots (20 m x 20 m), within which we counted and identified to species adult and juvenile trees. We counted and identified to species herbaceous plants and tree seedlings in five 2 m x 2 m quadrats nested within each plot. We measured environmental variables (% canopy, % bare soil, % woody debris and distance from road or building) in each quadrat.The CSA forest is under stress from anthropogenic disturbance and invasive species. Long-term monitoring of forest community composition could augment the efficacy of efforts to control invasive species at the CSA. The floristic quality index value (FQI), a unitless calculation of species per area, calculated for the CSA is 30 (based on 1.2-ha). FQI values calculated for the CSA in 2009 can be compared with those measured in later years to evaluate whether the plant community composition improves over time with management.Of 69 species found in plots, 9 were non-native, 3 of which were invasive. Invasive garlic mustard (Alliaria petiolata) and myrtle (Vinca minor) were the dominant understory species. Garlic mustard remains the priority for eradication efforts. With the exception of garlic mustard no invasive species were found in plots further than 20 m from roads and buildings. A volunteer-based monitoring program for early detection of “founder” populations of invasive species could be effective in controlling invasive species. The CSA acquired funds for the summer of 2010 to build demonstration plots to educate the community on invasive species removal. This study provides a template for scientists to collaborate with private communities interested in science-based management programs that promote conservation.

Latitudinal gradient of floristic condition among Great Lakes coastal wetlands

Coastal wetland vegetation along the Great Lakes differs strongly with latitude, but most studies of Great Lakes wetland condition have attempted to exclude the effect of latitude to discern anthropogenic effects on condition. We developed an alternative approach that takes advantage of the strong relationship between latitude and coastal wetland floristic condition. Latitude was significantly correlated with 13 of 37 environmental variables tested, including growing degree days, agriculture, atmospheric deposition, nonpoint-source pollution, and soil texture, which suggests that latitude is a good proxy for several environmental drivers of vegetation. Using data from 64 wetlands along the U.S. coast of Lakes Huron, Michigan, Erie, and Ontario, we developed linear regressions between latitude and two measures of floristic condition, the Floristic Quality Index (FQI, adj. r2=0.437, p<0.001) and the first axis scores from a non-metric multidimensional scaling of wetland plant cover (MDS1, adj. r2=0.501, p<0.001). Departures from the central tendency of these regression models represented wetlands of better or worse condition than expected for their latitude. This approach provides a means to identify wetlands worthy of preservation, to establish vegetation targets for wetland restoration, and to forecast changes in floristic quality associated with future climate change.

Evaluation of Restored and Native Prairie Pothole Region Plant Communities Following an Environmental Gradient

Historically, wetland and grassland ecosystems throughout the Prairie Pothole Region (PPR) of North America were shaped by fire, grazing, and alternating drought and deluge conditions. These historic disturbance patterns of the PPR have been altered by human modifications to the landscape. In recent years, managers have attempted to implement practices that simulate historic disturbance patterns in order to improve the diversity of structure and function in impacted ecosystems. This study evaluated the characteristics of restored and native wetland/grassland plant communities located within two National Wildlife Refuges (NWR) in the PPR of North Dakota. An extensive analysis of plant community composition following an environmental gradient was conducted in order to relate the composition and quality of wetland communities to the condition of adjacent upland grasslands and to compare the composition and quality of native and restored sites. Plant communities were evaluated using quadrat and transect methods and a Floristic Quality Index (FQI). Statistical analyses employed Nonmetric Multidimensional Scaling ordination and Multi-Response Permutation Procedure. We found wide variability in the composition and quality of the plant communities evaluated. Native plant communities were generally of higher quality than restored communities; also, plant communities located at Lostwood NWR generally contained more native components than those located at Tewaukon NWR. The results of this study show that restoration efforts, when properly managed, have the potential to improve the composition and quality of wetland and grassland plant communities. It is likely that the quality of the restored plant communities evaluated in this study will continue to improve with time and sustained management.

Is floristic quality assessment reliable in human-managed ecosystems?

The Floristic Quality Analysis (FQA) is a method to assess the quality of a flora based on the assignment of scores to plant species and subsequent calculation of indices. This method is widely applied, but inadequate investigation has been devoted to test its potential problems due to human factors. This work is aimed to specifically test how the human factor can affect the calculation of the FQA indices, by addressing three questions: (i) Are the scores given to plant species consistent among different experts?; (ii) Are the floristic quality indices calculated by different experts consistent in ordering individual sites?; and (iii) Does the use of an appropriate statistics change the ordering of individual sites? To answer these questions, a list of species obtained in 136 plots in central Italy was submitted to nine experts, who scored each species. The FQA indices were then calculated from the scores of each of the experts. The results showed that: (i) the scores given to the species by the experts were not consistent and the derived floristic quality indices were statistically different; (ii) the floristic quality indices calculated for each plot were significantly different among experts, but the ranking of these plots based on their floristic quality was rather consistent; and (iii) the use of ordinal statistics, which is more adequate for this type of data, did not change the results. This study demonstrated that the Floristic Quality Analysis does not provide reliable and objective tools to assess the quality of the flora in a human-managed ecosystem. The application of these indices should be preceded with resolution of the methodological problems associated with the use of inappropriate statistics, and by procedures to reduce the degree of subjectivity in assigning the CC scores.

Application of Two Quality Indices as Monitoring and Management Tools of Rivers. Case Study: The Imera Meridionale River, Italy

On the basis of the European Water Framework Directive (2000/60), the water resources of the member states of the European Community should reach good quality standards by 2015. Although such regulations illustrate the basic points for a comprehensive and effective policy of water monitoring and management, no practical tools are provided to face and solve the issues concerning freshwater ecosystems such as rivers. The Italian government has developed a set of regulations as adoption of the European Directive but failed to indicate feasible procedures for river monitoring and management. On a local scale, Sicilian authorities have implemented monitoring networks of watersheds, aiming at describing the general conditions of rivers. However, such monitoring programs have provided a relatively fragmentary picture of the ecological conditions of the rivers. In this study, the integrated use of environmental quality indices is proposed as a methodology able to provide a practical approach to river monitoring and management. As a case study, the Imera Meridionale River, Sicily's largest river, was chosen. The water quality index developed by the U.S. National Sanitation Foundation and the floristic quality index based on the Wilhelm method were applied. The former enabled us to describe the water quality according to a spatial-temporal gradient, whereas the latter focused on the ecological quality of riparian vegetation. This study proposes a holistic view of river ecosystems by considering biotic and abiotic factors in agreement with the current European regulations. How the combined use of such indices can guide sustainable management efforts is also discussed.

Trajectories of vegetation‐based indicators used to assess wetland restoration progress

Temporal trends in attributes of restored ecosystems have been described conceptually as restoration trajectories. Measures describing the maturity or ecological integrity of a restoration site are often assumed to follow monotonically increasing trajectories over time and to eventually reach an asymptote representative of a reference ecosystem. This assumption of simple, predictable restoration trajectories underpins federal and state policies in the United States that mandate wetland restoration as compensation for wetlands damaged during development. We evaluated the validity of this assumption by tracking changes in 11 indicators of floristic integrity, often used to determine legal compliance, in 29 mitigation wetlands. Each indicator was expressed as a percentile relative to the distribution of that indicator among > 100 naturally occurring reference wetlands. Nonlinear regression was used to fit two alternative restoration trajectories to data from each site: an asymptotic (negative exponential) increase in the indicator over time and a peaked (double exponential) relationship. Depending on the particular indicator, between 48% and 76% of sites displayed trends that were at least moderately well described (R2 > 0.5) by one of the two models. Floristic indicators based on species richness, including native richness, number of native genera, and the floristic quality index, rapidly increased to asymptotes exceeding levels in a majority of reference wetlands. In contrast, indicators based on species composition, including mean coefficient of conservatism and relative importance of perennial species, increased very slowly. Thus, some indicators of restoration progress followed increasing trajectories and achieved or surpassed levels equivalent to high-quality reference sites within five years, whereas others appeared destined to either not reach equivalency or to take much longer than mitigation wetlands are typically monitored. Finally, some indicators of restoration progress, such as relative importance of native species, often increased over the first five to 10 years and then declined, which would result in a misleading assessment of progress if based on typical time scales of monitoring. Therefore, the assumption of simple, rapid, and predictable restoration trajectories that underlies wetland mitigation policy is unrealistic.

A unifying approach for evaluating the condition of wetland plant communities and identifying related stressors

Assessment of vegetation is an important part of evaluating wetland condition, but it is complicated by the variety of plant communities that are naturally present in freshwater wetlands. We present an approach to evaluate wetland condition consisting of: (1) a stratified random sample representing the entire range of anthropogenic stress, (2) field data representing a range of water depths within the wetlands sampled, (3) nonmetric multidimensional scaling (MDS) to determine a biological condition gradient across the wetlands sampled, (4) hierarchical clustering to interpret the condition results relative to recognizable plant communities, (5) classification and regression tree (CART) analysis to relate biological condition to natural and anthropogenic environmental drivers, and (6) mapping the results to display their geographic distribution. We applied this approach to plant species data collected at 90 wetlands of the U.S. Great Lakes coast that support a variety of plant communities, reflecting the diverse physical environment and anthropogenic stressors present within the region. Hierarchical cluster analysis yielded eight plant communities at a minimum similarity of 25%. Wetlands that clustered botanically were often geographically clustered as well, even though location was not an input variable in the analysis. The eight vegetation clusters corresponded well with the MDS configuration of the data, in which the first axis was strongly related (R2 = 0.787, P < 0.001) with floristic quality index (FQI) and the second axis was related to the Great Lake of occurrence. CART models using FQI and the first MDS axis as the response variables explained 75% and 82% of the variance in the data, resulting in 6-7 terminal groups spanning the condition gradient. Initial CART splits divided the region based on growing degree-days and cumulative anthropogenic stress; only after making these broad divisions were wetlands distinguished by more local characteristics. Agricultural and urban development variables were important correlates of wetland biological condition, generating optimal or surrogate splits at every split node of the MDS CART model. Our findings provide a means of using vegetation to evaluate a range of wetland condition across a broad and diverse geographic region.

A novel method for floristic quality assessment using the vegetation of the Jiuding Mountain, Sichuan, China as an example

Floristic Quality Assessment (FQA) is proposed as a new method to assess floristic integrity. In the present study, we use both the conventional method broadly adopted in the USA and a new one proposed herein to assess the floristic quality of the Jiuding Mountain. For the application of the FQA, each plant species was assigned an integer from 0 to 10 termed coefficient of conservatism (C) based on its global distribution area. The coefficient shows the degree of fidelity of each plant species to the flora of the west slope of the Jiuding Mountain and represents a rank based on its distribution area. Those species receiving a C value of 0–1 are distributed all over the world, those receiving a C value of 2–3 mostly in tropical areas, and those receiving a C value of 4–6 broadly in temperate areas. Species with C values of 7–8 are endemic to China and those with coefficients 9–10 are restricted to the Hengduan Mountains or even endemic to the Jiuding Mountain. Based on the fact that different plant species show different relative importance values (IV), the new method estimates the weighted averages for the coefficient of conservatism called the weighted mean coefficient of conservatism ( w). The floristic quality index (FQI) was then derived from or w, native species richness (N) and non‐native species (A). As expected when using the new method, the dominant species of the communities obtained different Cs, which resulted in different ws and FQIws as compared to the conventional method.

A novel method for floristic quality assessment using the vegetation of the Jiuding Mountain, Sichuan, China as an example

Floristic Quality Assessment (FQA) is proposed as a new method to assess floristic integrity. In the present study, we use both the conventional method broadly adopted in the USA and a new one proposed herein to assess the floristic quality of the Jiuding Mountain. For the application of the FQA, each plant species was assigned an integer from 0 to 10 termed coefficient of conservatism (C) based on its global distribution area. The coefficient shows the degree of fidelity of each plant species to the flora of the west slope of the Jiuding Mountain and represents a rank based on its distribution area. Those species receiving a C value of 0–1 are distributed all over the world, those receiving a C value of 2–3 mostly in tropical areas, and those receiving a C value of 4–6 broadly in temperate areas. Species with C values of 7–8 are endemic to China and those with coefficients 9–10 are restricted to the Hengduan Mountains or even endemic to the Jiuding Mountain. Based on the fact that different plant species show different relative importance values (IV), the new method estimates the weighted averages for the coefficient of conservatism called the weighted mean coefficient of conservatism ( w). The floristic quality index (FQI) was then derived from or w, native species richness (N) and non-native species (A). As expected when using the new method, the dominant species of the communities obtained different Cs, which resulted in different ws and FQIws as compared to the conventional method.

Sand Prairie Communities of Matanzas Nature Preserve, Mason County, Illinois

The Matanzas Prairie Nature Preserve is located near Bath, Mason County, Illinois, in the extensive glacial sand deposits associated with the Illinois River. This Preserve contains the only remaining high quality wet-mesic sand prairie, shrub prairie, and sedge meadow associated with the Illinois River sand deposits. The sedge meadow, about 5 ha in size, was dominated by Carex stricta (Importance Value or IV of 66.6 out of 200), Calamagrostis canadensis, and Rosa palustris (both with IV's of 28.3). The wet-mesic sand prairie occurred on slightly higher ground and was dominated by Solidago canadensis (IV of 34.2), Andropogon gerardii (IV of 25.9), Carex stricta (IV of 21.9), Poa pratensis (IV of 18.0), and Euthamia graminifolia (IV of 17.7). Parts of the Preserve were shrub prairie with a ground layer similar to the wet-mesic sand prairie community. A total of 340 species of vascular plants were encountered on the Preserve: 5 fern and fern-allies; 100 monocots; and, 235 dicots. Except for Poa pratensis, which was among the dominant species in the wet-mesic sand prairie and shrub prairie, the 38 exotic species were rarely encountered (11% of the flora). The Floristic Quality Index (including exotic species) for the sedge meadow was 38.80, the wet-mesic sand prairie 43.65, and the shrub prairie 31.76.

Rapid Invasion of a Great Lakes Coastal Wetland by Non-native Phragmites australis and Typha

Great Lakes coastal wetlands are subject to water level fluctuations that promote the maintenance of coastal wetlands. Point au Sauble, a Green Bay coastal wetland, was an open water lagoon as of 1999, but became entirely vegetated as Lake Michigan experienced a prolonged period of below-average water levels. Repeat visits in 2001 and 2004 documented a dramatic change in emergent wetland vegetation communities. In 2001 non-native Phragmites and Typha were present but their cover was sparse; in 2004 half of the transect was covered by a 3 m tall, invasive Phragmites and non-native Typha community. Percent similarity between plant species present in 2001 versus 2004 was approximately 19% (Jaccard's coefficient), indicating dramatic changes in species composition that took place in only 3 years. The height of the dominant herbaceous plants and coverage by invasive species were significantly higher in 2004 than they were in 2001. However, floristic quality index and coefficient of conservatism were greater in 2004 than 2001. Cover by plant litter did not differ between 2001 and 2004. The prolonged period of below-average water levels between 1999 and early 2004 exposed unvegetated lagoon bottoms as mud flats, which provided substrate for new plant colonization and created conditions conducive to colonization by invasive taxa. PCR/RFLP analysis revealed that Phragmites from Point au Sauble belongs to the more aggressive, introduced genotype. It displaces native vegetation and is tolerant of a wide range of water depth. Therefore it may disrupt the natural cycles of vegetation replacement that occur under native plant communities in healthy Great Lakes coastal wetlands.

Performance Criteria, Compliance Success, and Vegetation Development in Compensatory Mitigation Wetlands

The US Army Corps of Engineers often requires wetland creation or restoration as compensation for wetlands damaged during development. These wetlands are typically monitored postconstruction to determine the level of compliance with respect to site-specific performance standards. However, defining appropriate goals and measuring success of restorations has proven difficult. We reviewed monitoring information for 76 wetlands constructed between 1992 and 2002 to summarize the performance criteria used to measure progress, assess compliance with those criteria, and, finally, to evaluate the appropriateness of those criteria. Goals were overwhelmingly focused on plant communities. Attributes used to assess the quality of restored plant communities, including percent native species and the Floristic Quality Index, increased over time but were apparently unrelated to the number of species planted. Compliance frequencies varied depending on site goals; sites often failed to comply with criteria related to survival of planted vegetation or requirements that dominant plant species should not be exotic or weedy, whereas criteria related to the establishment of cover by vegetation or by wetland-dependent plants were often met. Judgment of a site's success or failure was largely a function of the goals set for the site. Some performance criteria were too lenient to be of value in distinguishing failed from successful sites, whereas other criteria were unachievable without more intensive site management. More appropriate goals could be devised for restored wetlands by basing performance standards on past performance of similar restorations, identifying consistent temporal trends in attributes of restored sites, and using natural wetlands as references.

Flora and vegetation of Coneflower Glacial Drift Hill Prairie Natural Area, Moultrie County, Illinois

Abstract The vascular flora of Coneflower Glacial Drift Hill Prairie Natural Area in Moultrie County, east-central Illinois, was studied during the growing seasons of 2002 and 2003. The prairie is located on a steep SW-facing hillside of the Cerro Gordo Glacial Moraine, overlooking the Kaskaskia River Valley and Lake Shelbyville. The flora was documented by general reconnaissance, and the structure of the vegetation was sampled in September 2003 using 0.25 m2 plots placed along two transects. The site supported 164 vascular plant species (including one named hybrid). The native grasses with the highest importance values were Andropogon gerardii (big bluestem) and Schizachyrium scoparium (little bluestem). Important forbs included Euphorbia corollata (flowering spurge), Helianthus divaricatus (woodland sunflower), Ratibida pinnata (drooping coneflower), and Comandra umbellata (false toadflax). Exotic species were represented by 28 taxa, 16.4% of the flora. The community had a Floristic Quality Index of 38....

Using a Floristic Quality Assessment Technique to Evaluate Plant Community Integrity of Forested Wetlands in Southeastern Virginia

Abstract Given the continuing degradation of freshwater wetland ecosystems throughout the Southeast, there has been significant interest in developing methods and indices to evaluate and monitor wetland biological integrity. The purpose of this study was to adapt and test the ability of a vegetation-based assessment technique known as Floristic Quality Assessment to detect the level of human impact in hardwood flat wetlands of Southeastern Virginia. We measured plant species diversity and composition within each vertical stratum [herbaceous, woody understory (shrub and sapling), and canopy] of 11 wetlands. We calculated a Floristic Quality Index (FQI) for each layer, and tested for relationship to land use disturbance patterns within defined site buffer and watershed areas. We found floristic quality of the herbaceous layer and the sapling portion of the woody understory layer to be negatively correlated with level of land use disturbance at both buffer and watershed scales, suggesting that FQI scores wit...

Properties and performance of the Floristic Quality Index in Great Lakes coastal wetlands

The Floristic Quality Index (FQI) has been proposed as a tool that can be used to identify areas of high conservation value, monitor sites over time, assess the anthropogenic impacts affecting an area, and measure the ecological condition of an area. FQI is based on the Coefficient of Conservatism (C), which is a numerical score assigned to each plant species in a local flora, primarily from best professional judgment, that reflects the likelihood that a species is found in natural habitats. FQI is computed by multiplying the mean Coefficient of Conservatism (C) by the square root of species richness for an observational unit. Great Lakes coastal wetlands were used to assess the properties and performance of various species richness, Coefficient of Conservatism, and Floristic Quality indices, as well as compare C-value assignments from two U.S. states (Wisconsin and Michigan). FQI and species richness increased with sampling area according to a power function, but C more or less remained constant. Sampling schemes should therefore focus on controlling sampling area and minimally sampling each community type at a site. In some cases, Wisconsin and Michigan assigned different values of C to the same species, highlighting possible effects due to the somewhat subjective nature of C-value assignment. Coefficient of Conservatism and Floristic Quality indices were better at discriminating differences between sites, independent of a condition gradient, than species richness alone, but neither index type outperformed the other. Both types of indices were also found to be acceptable ecological indicators of condition, although Floristic Quality indices consistently outperformed Coefficient of Conservatism indices in this capacity. Regardless of the subjectivity involved with the assignment of C-values and that ‘floristic quality’ is a human concept and not a true ecosystem property, both Coefficient of Conservatism and Floristic Quality indices seem to be effective indicators of condition in Great Lakes coastal wetland

Estimating floristic integrity in tallgrass prairie

Indices are needed in habitat conservation and restoration to provide repeatable measures relevant to conservation goals. A monitoring and research program was established at Nachusa Grasslands in north-central Illinois (USA) to assess progress in tallgrass prairie restoration and reconstruction efforts and evaluate the effectiveness of indices used to measure community-level properties related to vegetation integrity. Indices selected for comparison included standard diversity measures (e.g., Shannon–Weiner Index, Evenness, Species Richness) and indices developed specifically to estimate vegetation integrity. These latter indices included two unweighted diversity indices, the Species Richness Index and Native Richness Index, and two indices weighted by characteristics of species composition, the Floristic Quality Index (FQI) and its component Mean Coefficient of Conservatism (Mean C). A coefficient of conservatism (CC) is an integer ranging from 0 to 10 assigned a priori to each taxon in a regional flora that estimates the fidelity of a species to natural areas (non-native and most ruderal species are assigned 0 or low values, respectively; species known primarily from natural areas are assigned higher values). All indices compared in this study were calculated using vegetation data collected from equal-sized sampling grids stratified across seven prairie units. The units included remnants and plantings representing a wide range of habitat quality. The FQI and Mean C explained the most variation among sites and were most effective at distinguishing recognized qualitative differences indicating they can be more informative than traditional species-diversity measures in assessing floristic integrity within community types. The FQI and Mean C are applicable to both quantitative ecological monitoring and plotless survey methods.

Testing the Efficacy of Species Richness and Floristic Quality Assessment of Quality, Temporal Change, and Fire Effects in Tallgrass Prairie Natural Areas

Abstract Despite extensive use, few studies have thoroughly tested competency of the Florist Quality Index (FQI) to assess vegetation quality by comparing it with alternative statistics and with independent measures in large data sets. We compared the efficacy of species richness and floristic quality indices in detecting temporal change and fire effects on quality within and among tallgrass prairie remnants. We calculated species richness at small (1/4-m2 plot) and large (total sample) scales, as well from a Species Richness Index (SRI) that integrates these measures. These statistics were compared with FQI, which assesses quality by integrating species richness with estimates of species conservatism (C values) to undisturbed natural vegetation. We made within-site comparisons of temporal change in dry-mesic and mesic prairie vegetation following 22 years of fire exclusion and then after five years of fire management. The among-site comparisons used 33 prairies that were graded as A or B quality and samp...

Effect of area and isolation on species richness and indices of Floristic Quality in Illinois, USA wetlands

The Floristic Quality Index (FQI) is a tool used to assess the conservation value of natural areas and monitor restoration success. Each native plant species is assigned a coefficient of conservatism, a subjective rating that describes its affinity for remnant natural areas. To calculate FQI, mean coeffcient of conservatism (mean C) at a site is multiplied by the square root of native species richness. However, use of FQI is sometimes problematic, mainly because it incorporates species richness, which often varies with factors other than site conservation value. We surveyed 231 wetlands in a contiguous landscape that included the Beaucoup Creek floodplain in southern Illinois, USA and investigated the influence of landscape and site characteristics on species richness, mean C, FQI, and the proportion of site floras made up by wetland species and exotic species. Species richness and FQI increased significantly with site area or perimeter, indicating a bias toward higher assessments of quality in larger areas. Species richness and FQI in emergent wetlands increased with sampling date, suggesting that these sites should only be surveyed late in the growing season. Mean C and the proportion of site flora made up by wetland species decreased with increasing interwetland distance, indicating that isolation affects species composition. Both decreasing area and increasing inter-wetland distance were associated with lower FQI scores. Mean C, although not completely area-independent, was less strongly correlated with sampling date or area and may provide a more robust indicator of relative site conservation value than FQI when using the metrics to evaluate conservation value of jurisdictionally delineated plant communities.

Floristic Assessment of the Henry Allan Gleason Nature Preserve, Mason County, Illinois

The Henry Allan Gleason Nature Preserve is located in the extensive glacial sand deposits associated with the Illinois River in central Illinois. An extensive sand dune is present within the preserve on which undisturbed dry sand prairie, disturbed dry sand prairie, and blow-out communities are present. The undisturbed sand prairie is dominated by Schizachyrium scoparium (42% of the importance value [IV]), along with Tephrosia virginiana, Opuntia humifusa, and Ambrosia psilostachya. The disturbed sand prairie is dominated by Eragrostis trichodes (24% of the IV), followed by Heterotheca camporum, Ambrosia psilostachya, and Rhus aromatica. Common species in an active blow-out includes Aristida tuberculosa and Cyperus grayioides, while nearly stabilized blow-outs have a high diversity characterized by Bouteloua hirsuta, Ambrosia psilostachya, and Eragrostis trichodes. A total of 172 plant species were found: 4 fern and fern-allies, 3 gymnosperms, 39 monocots, 126 dicots. Thirty-one non-native species were found, comprising about 18% of the flora. The Floristic Quality Index for the nature preserve is 41.33 when the non-native species are included in the calculations.