Floristic Quality Research Articles

Redistribution and impacts of nearshore berm sediments on the Chandeleur barrier islands, Louisiana

• Large portions of sand berm were breached and eroded through overwash processes. • Sediments increased elevation of wetlands and shoals, and in some areas created new shoals in overwash and drift zones. • Redistributed sediments increased vegetation productivity and establishment on many newly created shoals. • The redistributed sediments also encouraged an increase in floristic quality and island feature stability. • Sediments significantly changed the functional trends that were observed over the last 50 years.

Longitudinal evaluation of vegetation richness and cover at wetland compensation sites: implications for regulatory monitoring under the Clean Water Act

There has been regulatory concern over the appropriate length of time to monitor wetland sites restored or created as compensation for impacts permitted by a U.S. Clean Water Act permit. However there is very little longitudinal research on wetland compensation sites, and conclusions on compensation site development are usually drawn from the analysis of a chronosequence of sites of different ages. This approach has limitations, given the extent of changes in wetland compensation practices and performance standards over the past few decades. In this study we conducted vegetation surveys of 22 wetland compensation sites in a rapidly developing part of the Minneapolis-St. Paul metropolitan area in 1997 and 2010. We present data on changes over time in floristic richness and cover at the site level and at the level of wetland community type within each site. Our findings do not support the assumption that wetland compensation sites progress on a trajectory toward increasing diversity, floristic quality, or native cover over time. We find that, when data from all sites are considered together, emergent communities have suffered significant declines in both floristic quality and native plant cover, while wet meadow communities have gained species richness but not species diversity. There is some evidence that site richness and cover characteristics are converging toward a regional mean over time, as the species composition of wet meadows became significantly more similar over the survey period, and all community types have significant increases in woody cover. Our study suggests the importance of selecting appropriate compensation sites that avoid foreseeable hydrologic stresses, and does not support the position that 5 years of monitoring can assure the ongoing biotic integrity of wetland compensation sites.

Interaction mechanism between floristic quality and environmental factors during ecological restoration in a mine area based on structural equation modeling

Open-pit mining activities cause great damage to the local ecosystems. It is therefore necessary to assess and recover the vegetation status to maintain ecological stability. In this study, the Floristic Quality Index (FQI) was used to assess the vegetation habitat and the structural equation model (SEM) was applied to quantify the influences of different environmental factors on FQI in the Kunyang open-pit phosphate rock mine in Yunnan Province, China. Non-metric multidimensional scaling analyses revealed that great differences of vegetation community composition existed in the sampled plots, even those at similar distances to mining areas, which indicates that disturbing distance was not the only factor to determine the vegetation community. SEM results showed that Cu promoted the FQI most obviously (0.84), followed by Co (0.75), while the inhibition of Cd content in soil to the FQI was the most significant (−0.88), followed by TK (−0.82), and C (−0.79). Soil fertility quality and soil pollution indexes were also established to analyze the effects of comprehensive soil parameters on FQI. The results showed that the soil fertility quality index had a strong negative effect on FQI, which revealed that higher levels of TP, TN, TK, and other nutrients in the soil would produce ‘toxicity’ to the growth of vegetation. Findings from our study could provide a scientific method for assessing the ecological restoration results in the mining area.

Performance of rapid floristic quality assessment indices for increasing cost-effectiveness of wetland condition evaluation

This project tested whether rapid floristic quality indices can be used in North Carolina’s diverse wetland types, given the many cost-saving benefits that can be realized from using such indices. Vegetation plot data from 2030 North Carolina wetland plots were analyzed to test how well two floristic quality assessment indices, based on cover-dominant species and based on non-graminoid species, were correlated with full index values based on a comprehensive species list.Dominance based indices (Mean C and FQI) significantly correlated with Mean C and FQI using all species, but Mean C was more strongly correlated than FQI. Mean C of cover-dominant species correlated with the Ohio Rapid Assessment Method, but could only distinguish the lowest and highest North Carolina Wetland Assessment Method ratings. Removal of graminoids as a group, which are difficult to identify, did not appear to affect Mean C, even in herbaceous wetlands, though some wetlands were comprised of only graminoids; a dominance based index would still be useful in graminoid marshes. The availability of this cost-saving assessment tool will benefit researchers and practitioners looking for more expedient ways of assessing wetland quality or validating rapid assessments with direct measurements.

Assessing the success of hydrological restoration in two conservation easements within Central Florida ranchland.

In the USA, the United States Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) has restored millions of acres of wetlands through its Wetland Reserve Easement (WRE) programs. However, few quantitative studies have explored whether WREs have enhanced wetland hydrology and wetland plant communities. Additionally, USDA Compatible Use Permits for cattle grazing and other management practices are sometimes issued for WREs, but little is known about potential benefits/detriments of such practice on the success of wetland restoration. In this study, we tested if hydrological restoration of previously drained species poor pastures increased water depth and hydroperiod. Restoration involved plugging key ditches, adding water control structures and a berm. We also tested if hydrological restoration increased plant diversity (alpha and beta), floristic quality (using coefficient of conservatism) and increased the cover of wetland species (using species wetland status). Finally, we tested if cattle grazing had an effect on the success of restoration by comparing grazed plots to fenced plots. We studied two conservation easements (a total of 748 acres) located on semi-native pastures in central Florida, USA. We monitored vegetation using permanent transects stratified by vegetation type before (2004–2005) and after (2012) the restoration (2008). We assessed wetland hydroperiod using groundwater wells set up in 2003 and located within and outside the boundaries of these two easements. We used linear mixed models and multivariate analyses to compare vegetation and hydroperiods pre- and post-restoration. Number of flooded days increased following restoration in one of the easements, but we did not detect significant changes in hydrology in the other easement. Floristic quality, beta diversity and cover of obligate wetland species increased in both conservation easements and in most vegetation types. These vegetation changes were likely due to restoration activities since annual rainfall was not significantly different pre- and post-restoration. Cattle grazing did not have a negative or positive effect on the success of restoration, nor did we detect any positive effect of grazing on the success of restoration. Overall, our study shows that hydrological restoration can enhance wetland hydroperiod, water depth and wetland vegetation, but more resources should be allocated to short- and long-term monitoring of the restoration success.

A Comparison of Five Wetland Communities in a North Dakota Fen Complex

Fens are rare and not well-studied within the Prairie Pothole Region (PPR) of North Dakota. PPR wetlands (including fens) are vulnerable to land use alterations, particularly conversion to agricultural production. In this study, we described a 48-ha natural fen complex with five distinct wetland plant communities (denoted cattail [Typha L. spp.], floating mat [areas at higher elevation with an upward groundwater gradient], herbaceous, tree, and wet meadow). Our goal was to describe the wetland plant communities and determine possible factors driving the formation of several distinct wetland plant communities in close proximity to one another. We identified 148 plant species, six of which are considered priorities for conservation by the North Dakota Natural Heritage Program. We compared the composition of wetland plant communities using multi-response permutation procedure (MRPP) and examined individual attributes (e.g., species richness, evenness, diversity, Floristic Quality Index, percent introduced species, percent soil organic matter, pH, and electrical conductivity) of the wetland plant communities using ANOVA and Tukey's (HSD) test. We found the highest species richness, evenness, and diversity in herbaceous and tree communities and the lowest percent introduced species in floating mat communities. There were no significant differences in the soil properties tested among the five plant communities.

Assessment of Plant Diversity of a Seasonal Tropical Wetland Forest Ecosystem in Bangladesh

The quantitative analysis of plant diversity was explored on a seasonal tropical wetland forest ecosystem at Ratargul Swamp Forest. The simple random sampling protocol was adopted, and 30 plots (10 m×10 m) each with one subplot (2 m×2 m) was investigated for the vegetation survey. The study found about 539 individuals of 48 species belonging to 36 families. Poaceae was the dominant among all family. The upper (trees with all size) and lower (shrubs, herbs, climbers, grasses) stratum was dominated by Pongamia pinnata and Clinogyne dicotoma, respectively. The taxonomic diversity was moderate in both lower and upper strata. The value of floristic quality index was calculated at 19.92, which represents moderate vegetative quality. The outcome also revealed the disturbances which influenced the plant community, mostly due to branch cutting by human (<30%). The findings will be useful for the conservation and scientific management of biodiversity as a hotspot in seasonal tropical wetland forest system.Keywords: Biodiversity, conservatism, disturbance, hotspot, wetland

Evaluating how variants of floristic quality assessment indicate wetland condition

Biological indicators are useful tools for the assessment of ecosystem condition. Multi-metric and multi-taxa indicators may respond to a broader range of disturbances than simpler indicators, but their complexity can make them difficult to interpret, which is critical to indicator utility for ecosystem management. Floristic Quality Assessment (FQA) is an example of a biological assessment approach that has been widely tested for indicating freshwater wetland condition, but less attention has been given to clarifying the factors controlling its response. FQA quantifies the aggregate of vascular plant species tolerance to habitat degradation (conservatism), and model variants have incorporated species richness, abundance, and indigenity (native or non-native). To assess bias, we tested FQA variants in open-canopy freshwater wetlands against three independent reference measures, using practical vegetation sampling methods. FQA variants incorporating species richness did not correlate with our reference measures and were influenced by wetland size and hydrogeomorphic class. In contrast, FQA variants lacking measures of species richness responded linearly to reference measures quantifying individual and aggregate stresses, suggesting a broad response to cumulative degradation. FQA variants incorporating non-native species, and a variant additionally incorporating relative species abundance, improved performance over using only native species. We relate our empirical findings to ecological theory to clarify the functional properties and implications of the FQA variants. Our analysis indicates that (1) aggregate conservatism reliably declines with increased disturbance; (2) species richness has varying relationships with disturbance and increases with site area, confounding FQA response; and (3) non-native species signal human disturbance. We propose that incorporating species abundance can improve FQA site-level relevance with little extra sampling effort. Using our practical sampling methods, an FQA variant ignoring species richness and incorporating non-native species and relative species abundance can be logistically efficient, easily understood, and effective for wetland assessment.

FQA: A method for floristic quality assessment based on conservatism of plant species

FQA, which uses the conservatism of plant species for particular habitats and the species richness of plant communities, is a rapid method for the assessment of habitat quality. This method is based on species composition of quadrats and coefficients of conservatism for species which assigned by experts. Floristic Quality Index (FQI) that reflects vegetation integrity and degradation of a site can be calculated by a simple formula and be used for space-time comparison of habitat quality. It has been widely used in more than ten countries including the United States and Canada. This paper presented the principle, calculation formulas and application cases of this method, with the aim to provide a simple, repeatable and comparable method to assess habitat quality for ecological managers and researchers.

Patterns of vegetation and soil properties in a beaver-created wetland located on the Coastal Plain of Virginia

This study investigated vegetation and soil properties in a beaver-created freshwater wetland located on the Coastal Plain of Virginia near Washington, DC. We focused on the associations among floristic quality, soil physicochemistry, denitrification, and hydrologic conditions of the wetland to understand links between the effects of beaver engineering and ecosystem function. The floristic quality assessment index (FQI) and denitrification are two important indicators often used to examine overall habitat quality and ecosystem functioning of a wetland. Samples were collected from ten plots (10 m × 10 m each) in August 2014. Vegetation attributes included total percent cover, species richness (S), diversity, FQI, and prevalence index (PI). Soil attributes included organic matter (OM), total carbon, total nitrogen, gravimetric moisture (GM), pH, bulk density (Db), and denitrification potential (DP). FQI was greater in the higher of the two standing water level categories, where Db was lower, and was negatively associated with Db but no other soil nutrient properties. DP was positively associated with soil nutrients, OM, and GM, but not with measured vegetation attributes nor standing water levels. We found higher soil GM, lower plant community PI, and lower plot S in this study compared to our previous study, with no changes to other vegetation or soil attributes, indicating enduring beaver activity and a resilient plant community. The outcome of the study includes regression models that best explain the association between structural and functional attributes of the ecosystem, which can be applicable to the study of other beaver-created wetlands. The study also provides partial evidence for the notion that low-lying areas dug out by beaver positively impact the FQI of wetlands.

Structural and functional characteristics of buffer strip vegetation in an agricultural landscape – high potential for nutrient removal but low potential for plant biodiversity

Vegetated buffer strips constitute a transition zone between terrestrial and aquatic ecosystems and provide several ecosystem services. Buffer strips are often applied as a mitigation measure against diffuse pollution in agricultural areas, primarily because they may retain nutrients and in this way help protect the aquatic environment. Additionally, they can improve biodiversity in an otherwise homogenous landscape and may therefore have a value in their own right. In the present study, we characterized the structural and functional features of the vegetation in Danish buffer strips using a nationwide dataset to explore: i) their floristic quality in terms of species diversity and conservation value and ii) based on their functional characteristics, their potential to retain nutrients. Moreover, we analyzed how the structural and functional characteristics varied along gradients in the environmental features of the catchment. We found that the floristic quality of the buffer vegetation was generally low, exhibiting an average of only 3.3% of the number of species of conservation interest. Instead, Danish buffer strips were dominated by widespread and productive species that are tolerant of anthropogenic impacts in the catchment. The abundance of highly productive plant species was positively related to high intensity land use, whereas the abundance of stress-tolerant plant species was positively related to low intensity land use. The high productivity of the buffer strips implies a large bio-storage potential, and these areas might therefore offer an opportunity to remove nutrients by harvesting the plant biomass. We discuss how Danish buffer strips could be exploited via appropriate management (e.g. harvesting) to maximize nutrient retention and at the same time improve floristic quality.

Development of a plant based riparian index of biotic integrity (RIBI) for assessing the ecological condition of highland streams in East Africa

The study of riparian plant communities along running streams offers information on the state of habitat and can help increase our knowledge on the use of bioindicators. We developed a riparian index of biotic integrity (RIBI) to evaluate the conditions of highland streams in response to anthropogenic disturbances in the southwest Ethiopian highland. To construct RIBI, we evaluated 22 potential plant metrics. Disturbance was quantified for each site using information on canopy openness, ground area without vegetation and exposed mineral soil. Five core metrics (floristic quality indexes, average C, native tree/shrub species, riparian status species and Shannon diversity index) were found to respond to anthropogenic disturbances. These metrics were significantly differentiated among sample sites categorized as low and high disturbance sites (p < .001). The core metrics and RIBI scores for this data set were also significantly correlated with environmental variables including riparian buffer width, dissolved oxygen, water temperature, turbidity, total suspended sediment, nitrate and orthophosphate. These findings provide support for the continued use of plants as indicators of highland stream condition in the East Africa, providing that the responses of plant based metrics to disturbances. Thus, the RIBI could be useful tool for the assessment and monitoring of stream ecosystems and evaluating the effect of stream restoration in the East African highland in the future.

Ecology of Floristic Quality Assessment: testing for correlations between coefficients of conservatism, species traits and mycorrhizal responsiveness.

Many plant species are limited to habitats relatively unaffected by anthropogenic disturbance, so protecting these undisturbed habitats is essential for plant conservation. Coefficients of conservatism (C values) were developed as indicators of a species' sensitivity to anthropogenic disturbance, and these values are used in Floristic Quality Assessment as a means of assessing natural areas and ecological restoration. However, assigning of these values is subjective and improved quantitative validation of C values is needed. We tested whether there are consistent differences in life histories between species with high and low C values. To do this, we grew 54 species of tallgrass prairie plants in a greenhouse and measured traits that are associated with trade-offs on the fast-slow continuum of life-history strategies. We also grew plants with and without mycorrhizal fungi as a test of these species' reliance on this mutualism. We compared these traits and mycorrhizal responsiveness to C values. We found that six of the nine traits we measured were correlated with C values, and together, traits predicted up to 50 % of the variation in C values. Traits including fast growth rates and greater investment in reproduction were associated with lower C values, and slow growth rates, long-lived leaves and high root:shoot ratios were associated with higher C values. Additionally, plants with high C values and a slow life history were more responsive to mutualisms with mycorrhizal fungi. Overall, our results connect C values with life-history trade-offs, indicating that high C value species tend to share a suite of traits associated with a slow life history.

Short-term Change in Forest Metrics at Grand Portage National Monument, Minnesota

Forest health monitoring programs can provide routine feedback of key indices and periodic updates of ecosystem health. A forest monitoring program was initiated at Grand Portage National Monument in 2007 with plots resampled in 2014. Grand Portage National Monument is within the southern boreal forest and the suitable habitat for most of its common overstorey species is expected to shift northward and out of the park as climate change progresses. We assessed short-term change in forest health on 20 plots by specifically evaluating change in overstorey density and basal area, forest community composition, and White-tailed deer (Odocoileus virginianus) browsing impacts on the herbaceous layer. Pooled across all overstorey species, both density and basal area increased between sampling events, but neither differed among habitats. For individual species of interest, responses were varied, although balsam Fir (Abies balsamea) increased in both density and basal area over the seven years. The frequency of quadrats supporting at least one preferred browse species did not differ between sampling years although this was greater in upland plots (81%) compared with wet mesic sites (66%). The effect of sampling year on species’ richness depended on habitat. In 2007, richness was higher in upland plots, although in 2014, richness was higher in wet mesic plots. Pooled across both sampling years, modified floristic quality index was greater in wet mesic plots. Our work demonstrates the increasing dominance of A. balsamea at Grand Portage National Monument and that notable differences in forest metrics can be observed over relatively short times.

Soil carbon sequestration in freshwater wetlands varies across a gradient of ecological condition and by ecoregion

We evaluated the ability of freshwater riparian wetlands along a gradient of ecological condition to act as sinks for carbon and sediment. We compared rates of carbon accretion and soil accretion across 20 wetlands in the Lake Erie Drift Plain and the Ridge and Valley ecoregions. Soil cores were collected and analyzed using 137Cs dating to quantify long-term (∼50year) rates of sediment and carbon accumulation. Data on hydrology and floristic quality were used to help explain variability in rates. Sites were classified as being in low, moderate, or high ecological condition based on a rapid assessment method, which was verified by their floristic quality. Wetlands of low ecological condition (more human disturbance) had higher mean soil accretion and carbon accretion rates. Soil accretion averaged 0.24±0.17cmyr−1 and 0.14±0.04cmyr−1 in low condition sites and high condition sites, respectively. Carbon accretion averaged 88±50gCm−2yr−1 in low condition and 65±27gCm−2yr−1 in high condition sites. Low condition sites had lower mean soil carbon concentrations in the upper 10cm of the soil profile, suggesting that the higher carbon burial in these sites was related to allochthonous carbon inputs in incoming sediment, rather than autochthonous carbon inputs. There were also striking rate differences between ecoregions. Erie Drift Plain wetlands had significantly higher mean soil accretion rates, compared to Ridge and Valley wetlands. These data indicate that freshwater wetlands play a role in regulating climate by acting as carbon sinks and that anthropogenic disturbance can impact rates of carbon burial.

Plant Functional Group Composition on Restored Longleaf Pine—Wiregrass (Pinus palustris—Aristida stricta) Savannas with a History of Intensive Agriculture

ABSTRACT: We monitored plant community assembly during the first five years of longleaf pine—wiregrass (Pinus palustris—Aristida stricta) savanna restoration on four former bahiagrass (Paspalum notatum) pastures in peninsular Florida, which were restored via removal of exotic vegetation followed by mechanical planting with a wild-harvested native seed mix. We sampled randomly selected vegetation quadrats in each restored pasture annually, as well as randomly selected quadrats in each of four reference sites. All species were assigned to one of five functional groups (C4 graminoids, C3 graminoids, forbs, legumes, or shrubs) and one of three floristic quality categories (characteristic, pioneer, or weedy). Five years after restoration, we found that native C4 graminoids had supplanted the sod-forming P. notatum as the dominant graminoids on all sites. Restored sites had higher average C4 graminoid and forb cover than reference sites, but lower average species richness in both categories. Reference sites had...

Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie.

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies (P < 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies (P < 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI (P < 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

Floristics of the Abrams Creek Wetlands, a Calcareous Fen Complex in Winchester City and Frederick County, Virginia

ABSTRACT The 24-ha Abrams Creek Wetlands (Winchester City and Frederick County, Virginia) is an array of fen, swamp, and disturbed transitional ecosystems underlain by limestone and dolostone bedrock. Soils of the area are generally characterized by exceptionally high levels of calcium (>10,000 ppm). Floristic data were collected through monthly surveys during the 2012–14 growing seasons and plot sampling in representative locations. We documented 296 vascular plant species during the inventory period; eight species found previously were not relocated. The 304 total species comprised 206 genera in 78 families. Of these, 55 species were graminoids (27 grasses, 21 sedges, 7 rushes). Obligate or facultative wetland species comprised 43% of the list. The 216 native species represented 71% of the total and included 20 listed as rare in Virginia. Plot data revealed that native species represented 72–99% of the total vegetative cover in the communities sampled. Floristic quality of the 12 constituent sites was ...

Floristic quality as an indicator of human disturbance in forested wetlands of northern New England

Across the country, degradation of freshwater wetlands has prompted a need for science-based methods for assessing and monitoring wetland condition. Floristic Quality Assessment (FQA) is an assessment that measures the health of an ecosystem. FQA is based on resilience values called Coefficients of Conservatism (C-values), preassigned to each plant species. The method has proven to signal human disturbance in most wetland types, but is understudied in forested wetlands. We compared FQA scores and Ecological Integrity Assessment (EIA) scores (Level 2) of 11 red maple − Sphagnum basin swamps (RMSBS) of New Hampshire and 12 red maple swamps (RMS) of southern Maine to test the hypothesis that FQA signals human disturbance in forested wetlands. EIA did not distinguish RMSMS from RMS, however Mean C, Cover Weighted Mean C (wC), and FQI did. In RMSBS, wC showed the strongest positive correlation with EIA scores. In RMS, Mean C showed the strongest positive correlation with EIA scores. For all sites combined, wC and Mean C were significantly correlated with EIA scores. Meaningful relationships were not observed between FQI or wFQI and EIA scores. The results indicate that Mean C and wC offer a reliable metrics for the evaluation of forested wetlands in northern New England.

Vegetation productivity of planted and unplanted created riverine wetlands in years 15–17

Wetland creation and restoration have been key factors in reducing net loss of wetland habitat in the United States. Creation and restoration techniques, such as introducing vegetation, are perceived to have a long-term effect on wetland structure and function over time. The goal of this study was to compare macrophyte structure and function between a planted and unplanted (naturally colonizing) wetland more than 14 years after the wetlands were created in 1994 at the Olentangy River Wetland Research Park in central Ohio, USA. Species richness, floristic quality, community diversity, and aboveground and belowground productivity were examined throughout the growing season for Years 15 through 17 of these wetlands.The planted wetland had higher floristic quality assessment index scores (planted 23.2–23.8; unplanted 19.9–20, p=0.001). Community diversity was similar between the two wetlands (CDI: planted 1.16–1.71; unplanted 1.03–1.45, p=0.388). Aboveground net primary productivity of emergent vegetation was higher in the unplanted wetland (796–866g dry weight m−2 yr−1) than in the planted wetland (673–712g dry weight m−2 yr−1) (p=0.006). While planting a riverine wetland may not be as important as planting isolated wetlands, this study did find some differences in structure and function in the planted and unplanted wetlands more than14 years after the wetlands were created. While planting riverine wetlands may aid in increased floristic quality of the wetland in the short term, these two wetland marshes appeared to be converging overall in structure and function during the 3 years of this study.