Comparative floristic diversity of Spring Creek and Nine-Mile Prairies, Nebraska.
Spring Creek Prairie (SCP), in Lancaster County, Nebraska, was purchased by Audubon Nebraska in 1998 and is being restored for educational purposes and scientific study. It is a remnant tallgrass prairie of 247 ha (610 acres) that was grazed for a century but never plowed. The research was conducted to obtain baseline information about diversity and abundance of upland species, for assessment of management practices. Specimens were collected from September, 1998, through October, 2000, and an inventory was produced. These data were compared with similar data from Nine-Mile Prairie (NMP), a nearby and essentially ungrazed virgin tallgrass prairie that is now managed with prescribed burning. Seventy-eight percent of the 349 species at SCP are native and 22% are non-native. At about one-third the size, NMP contains 398 species, with 85% native and 15% non-native. Sampling data from the fall of 1999 indicated greater richness at SCP, while actual plant species inventories showed greater total richness at NMP. Ruderal and introduced species are significantly more abundant at SCP. Richness assessed using the "Chicago Method" indicated lower values at SCP than NMP, as did Simpson's diversity index. Detrended correspondence analysis, frequency, and basal cover indicated a greater propensity for warm-season grasses at NMP and for ruderal grasses and forb species at SCP.
Spring Creek Prairie (SCP), near Denton in Lancaster County, Nebraska, is home to Audubon Nebraska headquarters and is being restored for educational purposes and scientific study. This tallgrass prairie is part of the largest remaining area of unplowed rangeland in Lancaster County, and it is near the western edge of the vast tallgrass prairie region of central North America. Landowners indicated that most of the area was grazed for the past century, as was SCP. The Nebraska City-to-Fort Kearny cutoff of the Oregon Trail passed through the land in the 1860s, and the surviving ruts are deep.
The objectives of this study were (1) to produce an inventory list and herbarium specimens of all existing species at Spring Creek Prairie, and (2) to compare the diversity and abundance of upland species at heavily and long-grazed SCP with those of essentially never-grazed Nine-Mile Prairie (NMP), the nearest surviving prairie that resembles pre-settlement vegetation, and which is now managed with prescribed burning. Comparisons between the two prairies are here restricted to the same number of sites per hectare having similar soil types. Comparing sites with identical climatic conditions and soil types, yet with two very different management histories, can tell us something about the differences of the effects of management on diversity.
In addition, data-collection was designed to assist the SCP management committee in its prairie-management and -recovery goals, by recording the richness and abundances of introduced and native species.
The common vision of presettlement flora is that described by conditions of the recent past, approximately 200 years ago, when the area was occupied by Native Americans and frequented by herds of bison and other grazing animals. It presents tallgrass prairie vegetation as dominated by warm-season grasses and an abundance of forbs. Native Americans burned the prairies as protection from enemies, in ceremonial rites, and as a means of increasing crop yields. This practice, along with lightning-started tires and grazing, may have helped to form the present tallgrass prairie. With this in mind, "presettlement vegetation" herein means vegetation of pre-European-settlement, to compare with the present-day prairie vegetation.
Diversity measures are used as indicators of the well-being of an ecosystem (Magurran 1988). A highly diverse prairie is one in which species are equally abundant, but diversity is compromised when one or a few species are dominant. The more highly diverse grasslands are more stable and less likely to be harmed by drought stress than species-poor areas (Tilman and Downing 1987). Connell (1978) considered species richness to be a direct measure of species diversity. Though direct, it may not be accurate. A total-species list will verify the results of richness sampling, and measures of diversity, when compared to richness, will provide a more accurate assessment than either measure alone.
SITES AND METHODS
Spring Creek Prairie
Spring Creek Prairie is a 247 ha (610 acres, almost one square mile) tract that includes most of section 3 in T8N, R3E of Lancaster County, Nebraska. Included on this tract are uplands, wetlands, ponds, a creek, springs, seeps, and riparian woodlands (Fig. 1). It was purchased in 1998 to be headquarters for Audubon Nebraska.
[FIGURE 1 OMITTED]
Spring Creek Prairie has a long history of human disturbance. The land was owned by the Burlington Missouri River Railroad from 1872 to 1886. It was then held by various private owners until it was sold to the O'Brien family in 1903, and it has been used for cattle and horse ranching since before 1903. At the time of the present study, there were two abandoned alfalfa fields, one cultivated field, a sand-filled barrel racing arena, and a sparsely landscaped homestead, in addition to the much larger native landscape features mentioned above. A cutoff of the Oregon Trail passes through the land, and the surviving ruts are being preserved.
Lancaster County is part of the tallgrass prairie ecosystem matrix. The tallgrass prairie is dominated by Andropogon gerardii (big bluestem), Schizachyrium scoparium (little bluestem), Sorghastrum nutans (Indiangrass), Panicum virgatum (switchgrass), and various forbs. This vegetation type covers close to 80% of SCP. Wetland, woodland, and cultivated areas make up the remaining 20%.
Spring Creek runs the length of the property from south to north. Wetlands lie between two man-made ponds along Spring Creek. An oak-ash-elm woodland covers the northern section of the Spring Creek Valley and surrounding upland areas. A rotational grazing system recently has been implemented at SCP. Spring burning is used to combat cool-season exotic species. Gleditsia triacanthos (honey-locust) and Ulmus pumila (Siberian elm) trees are being removed.
Comparison data were taken at Nine-Mile Prairie (NMP), 19 km (12 miles) to the north of SCP (Fig. 2), on the northwestern edge of the City of Lincoln, in sections 1 and 2 of T10N, R5E of Lancaster County. This 97-ha (240 acres) site includes two small ponds, streams, uplands, and wooded riparian areas, altogether supporting 398 species (Kaul and Rolfsmeier 1987; Kaul, personal communication 2000).
[FIGURE 2 OMITTED]
Nine-Mile Prairie has been studied since the early 1900s. It was hayed and occasionally grazed until 1979, but it was never plowed. Since 1979, rotational spring burning has been conducted among three sections of the prairie, so that each section is burned once every three years. One area was farmed until the early 1950s and then was abandoned and allowed to revegetate through secondary succession.
Soils, topography, and climate
Soil in the SCP area is of the Steinauer-Pawnee-Burchard association (Soil Conservation Service 1980). Steinauer soils are fine-loamy, mixed (calcareous) mesic Typic Udorthents. Pawnee soils are fine, montmorillonitic, mesic Aquic Arguidolls, and Burchard soils are fine-loamy, mixed, mesic Typic Arguidolls. These soils are generally well drained, loamy to clayey soils formed on glacial till. The slopes at SCP are gentle to very steep and make erosion a concern.
The soils of NMP (Fig. 4) are of the Sharpsburg-Pawnee-Burchard association (Soil Conservation Service 1980). Sharpsburg soils are fine-loamy, montmorillonitic, mesic Typic Arguidolls. NMP has gently sloping to steep hills, and moderately to well drained silty soils in loess and loamy soils in glacial till on the uplands.
[FIGURE 4 OMITTED]
The two sites have four soil types in common: Burchard clay loam with 6-11% slopes (BrD), Burchard clay loam with 11-15% slopes (BrE), Pawnee clay loam with 2 to 7% slopes (PaC2), and Steinauer loam with 11-30% slopes (StF). A random selection of plots within these soil types was used for comparison between the two prairies.
Average annual precipitation in Lancaster County is 81 cm (32 in) (Soil Conservation Service 1980), most of it falling during the subhumid growing season. Summer and winter temperatures average 24.4[degrees]C and -2.8[degrees]]C (76[degrees] and 27[degrees]F), respectively.
Inventory: The taxonomic scope of this survey included all terrestrial and aquatic vascular plants of SCP. The study began in late August, 1998, with twice-weekly collections of voucher specimens until frost. Sites of localized diversity were visited often, and remaining areas were visited every few weeks. Collections were made from March, 1999, through October, 2000. Records of sightings and anticipated dates of anthesis were recorded in 1999 and were used to assist with collecting in 2000. Techniques used for collection generally followed those described by Forman and Bridson (1989). Specimens were collected mostly in triplicate, and care was taken to ensure the regional survival of species. Species for which only one plant was found were photographed, and a stem or flower and leaf were the only parts collected.
Specimens were placed in a plant press and dried for an average of four days in a drying oven set at 40[degrees]-44[degrees]C (100[degrees]-110[degrees]F). Temperature and drying time varied, depending on the species and on a specimen's estimated moisture content. The specimens were then mounted on herbarium paper and labeled. A map of Spring Creek Prairie was marked with a grid (Fig. 3) and the location of each plant was indicated. A red mark was placed on a small map on the label itself. Specimens were identified using Great Plains Flora Association (1986) and Hitchcock and Chase (1971). Sets of specimens were deposited in the Bessey Herbarium of the University of Nebraska-Lincoln and in Audubon Nebraska headquarters at SCP.
[FIGURE 3 OMITTED]
All specimens were listed in a computerized database, including the specimen number, scientific and common name, location, date, provenance, approximate date of anthesis, habitat, and coefficient of conservatism (sic, Swink and Wilhelm 1994). Provenance was recorded as "I" for introduced or "N" for native. While the word "introduced" implies origination from horticultural plantings, for convenience it is used in a more general sense throughout this study to mean non-native species originating outside Nebraska, regardless of the method of introduction.
Abundance and frequency: Upland plants were sampled in 48 plots at SCP, in a stratified random design (Fig. 3). These plots were divided among six areas, based on the pattern of grazing-control fences within SCP. The objective was to provide a baseline indication of plant diversity in addition to the inventory. Eight plots were sited in each of five pastures, and six were in ungrazed areas. Two plots (in addition to the original eight) were placed in a pasture where burning was to be conducted in 1999. These two additional plots provided a total of eight plots in the area to be burned. The plots were sited to provide data on species abundances under different management practices in different pastures; however, due to incidental management decisions, grazing occurred on all pastures in SCP during the 1999 season. Nine plots were established at NMP in areas with similar soil type as those at SCP, to allow comparison of two different management regimes (Fig. 4).
Plots were 1 x 10 m and were permanently marked. Each was divided into 10 subplots measuring 1 x 1 m. In early June and again in early September, forb species within each subplot were identified, counted, and recorded (Kottas 2000).
Within each of the 48 plots at SCP and the nine plots at NMP, the grasses and grass-like plants were recorded for each subplot. At SCP, the cool-season grasses were recorded in June and the warm-season grasses in September. Because data were not collected in the spring of 1999 at NMP, frequencies for both cool and warm-season grasses were recorded in September. Abundance data also provided frequencies for all other species. Basal area was measured at both sites, using a modified sampling system similar to that used by Anderson in the Flint Hills of Kansas (Anderson 1951).
In June of 2000, frequencies of forbs and grasses were again recorded at SCP and NMP. These data were collected within the original nine plots at NMP and within 17 randomly chosen plots at SCP. To adjust for sample size and soil types, plots of similar soil type from SCP were randomly chosen to equal the number of plots per hectare at NMP. At NMP, nine plots on 68 hectares (167 acres) of upland soils in common with SCP soils was equivalent to 17 plots on 130 hectares (320 acres) of upland area on the same soil types at SCP.
When the original plots were being sampled, a 10 x 10 m plot was constructed to inclue the original plot and the area to the south. Frequencies of vegetation were recorded for the original plot as well as for the additional area of the larger plots. The purpose of this sampling was to determine if a larger sampling area had a significant effect on the outcome of richness for these two sites. Floristic Quality Indexing done by Swink and Wilhelm (1994) and others (Rolfsmeier and Steinauer, unpublished) used the larger 10 x 10 m plots.
The sampling schedule is shown below:
September 1998 Inventory sampling begins June 1999 Abundance of forbs at SCP (48 plots) Frequency of forbs, trees, cool-season grasses, and grasslikes September 1999 Abundance of forbs at SCP (48 plots) Frequency of forbs, trees, warm-season grasses, and grasslikes Basal (modified line-intercept) data Abundance, frequency and basal data as above on 9 plots at NMP June 2000 Frequency of forbs, trees, grasses and grasslikes at SCP and NMP (9 plots each) in both 1 x 10 m plots and 10 x 10 m plots October 2000 Inventory sampling ends
Simpson's Index: Simpson's index presents diversity of species. It represents the probability that any two individuals selected at random are the same species. Thus, a very low index indicates a high diversity (Simpson 1949). It is calculated by
SI = [summation]ni(ni-1)/N(N-1)
Where n = the number of individual plants in ith species and N = the total number of individuals sampled. The same nine plots at SCP were used in the adjusted values as before. Using the reciprocal value of Simpson's index gives increasing values for increasing diversity (Magurran 1988).
Floristic Quality Index--The Chicago method: Floristic Quality Index (FQI), also referred to as the Chicago method, is a measure of richness that assesses the conservation value of a site. Each species in the flora of a region is assigned a coefficient of conservatism (C) ranging from 0 to 10, according to its observed pattern of behavior and occurrences (Swink and Wilhelm 1979, 1994). Species in Nebraska were recently assigned conservatism values by Rolfsmeier and Steinauer (unpublished). Introduced species were given no value, and a zero was used in calculations. Native ruderal species adapted to severe disturbance were given values of 0 to 3. Species included in the dominant native matrix were considered competitor species and are given values of 4 to 6. Values of 7 to 10 were given to species of late seral stages that do not tolerate disturbance (Rolfsmeier and Steinauer, unpublished). These C values were averaged for those species present, then multiplied by the square root of sampled species richness.
Detrended correspondence analysis: Multivariate analysis was applied to abundance data for forbs and to basal area data for grasses and grass-like plants (McCune and Mefford 1995). Data were grouped into vegetation classes reflecting four classes of conservatism values, as taken from Floristic Quality Assessment (Swink and Wilhelm 1979, 1994, Wilhelm and Masters 1995, Rolfsmeier and Steinauer, unpublished). Detrended correspondence analysis (DCA) is an ordination technique based on improvements on reciprocal averaging (RA) (Hill and Gauch 1980). DCA components are derived from weighted averages based on Chi-squares distance measures ordinating both species and samples simultaneously (McCune and Mefford 1995). DCA produces a series of axes representing progressively less of the variance among samples. The first three axes create a three-dimensional view of similarity among samples.
Statistical tests: To compare species composition between SCP and NMP, the differences in the richness of upland forb and shrub species were tested using a two-sample t-test. A two-sample t-test was also used to test the significance of differences in richness between 1 x 10 m plots and 10 x 10 m plots sampled in the spring of 2000. The occurrence of native versus introduced upland forb species (in 17 plots at SCP and the nine plots at NMP) was analyzed using a Chi-square test. A Chi-square test was used to test significance of difference in the abundance of adventive (C value < 4) vs. matrix and late seral species (C values > 3).
RESULTS AND DISCUSSION
The flora of SCP was sampled for a two-year period, and 349 species were collected, representing 75 families and 230 genera. No officially threatened or endangered species were found. One additional family and species was reported by photographic record: Campanulaceae, Campanula americana (American bellflower). A complete list of species recorded can be found in the Appendix 1. Of these 349 species, 273 (78%) are native, and 76 (22%) are introduced. By comparison, 398 species representing 73 families and 229 genera have been identified at NMP (Fig. 5, Appendix 1). Native species number 337 (85%) and introduced species 61 (15%). These figures reflect changes to the original species list of Kaul and Rolfsmeier (1987) through personal correspondence from those authors in 2000.
A summary of upland species indicates a total of 224 at SCP and 252 at NMP. Of these, 161 (72%) are native and 63 (28%) are introduced at SCP (Table 1). At NMP, 199 (79%) upland species are native and 53 (21%) are introduced. Chi-square tests showed no significant difference between the two prairies in the occurrence of native vs. introduced species in wetland and woodland/riparian vegetation categories, or in total species. Spring Creek Prairie did have significantly more introduced upland species than did NMP (p < 0.05).
Low numbers and/or exclusions of some species at SCP are of concern. Fewer than a half-dozen plants of Liatris aspera (rough gayfeather) were observed at this location. One plant each of Hedyotis nigricans (narrowleaf bluet), Asclepias tuberosa (butterfly milkweed), and Prenanthes aspera (white lettuce) were located. There were additional species, found outside fences marking the property boundaries of SCP, which were not included in the inventory list. These include Penstemon grandiflorus (shell-leaf penstemon), Ratibida columnifera (prairie coneflower), and Solidago speciosa (showy goldenrod).
A number of species have been found only on steep hillsides, outside fences, or on other areas where grazing pressure may be light. These include four members of the genus Helianthus (the sunflowers), Silphium integrifolium (rosin-weed), Silphium perfoliatum (cup plant), Solidago speciosa (showy goldenrod), Allium (wild onion), two species of Anermone, Liatris aspera (rough gayfeather), Hedyotis nigricans (narrowleaf bluet), Asclepias tuberosa (butterfly milkweed), Calylophus serrulatus (plains yellow primrose), and Aster sericeus (silky aster). In other instances, plants were found in abundance outside the fences and in far fewer numbers inside the fence at the same location. Echinacea angustifolia (coneflower) and Helianthus spp. (sunflowers) are examples.
In addition to relatively low numbers of individuals of many species, other species present on NMP were not found at SCP (Appendix 1). Pre-settlement species composition is not known, but comparison with the NMP list suggests more species can be found in comparable habitats. Of the 65 species found at SCP that do not occur at NMP, 43% are introduced ruderal species, 26% are native ruderal species, and only 31% are competitive tallgrass prairie species (Appendix 1). From NMP, 59% of the 114 species which do not occur at SCP are competitive species of the dominant tallgrass matrix, and 11% are late seral species. The remaining 30% are ruderal species including 14% that are introduced.
Richness and frequency of forbs and woody species
The average richness per 1 x 10 m plot was calculated for SCP in June of 1999 and September of 1999 (Fig. 6). The average number of species per plot in September was 21 at SCP. Cool-season grasses were counted in the spring and warm-season grasses were counted in fall data. These data include all 48 plots at SCP. Nine-Mile Prairie was not sampled in the spring of 1999, but the average number of species per plot was calculated for NMP in September of 1999. Data from SCP (the 17 plots of soil type in common with NMP) were used for comparison between NMP and SCP (Fig. 7). There were fewer forbs recorded per plot at NMP when the same number of plots per unit area were analyzed at SCP. Shrubs and trees were more numerous at NMP than SCP. This is accounted for by the inclusion of leadplant in nearly every plot at NMP. Greater richness at SCP is due, in part, to the 30% introduced upland species, one-third of which are not found at NMP.
Spring data in 2000 included nine plots from each prairie. Frequencies were recorded in the original 1 x 10 m plots and again in 10 x 10 m plots surrounding the original plots. The purpose of these data was to see if the richness measures for either prairie was influenced by larger plots. The richness recorded for the 10 x 10 m plots was significantly greater than that for 1 x 10 m plots on both prairies (p < 0.05). A very dry summer, fall, and spring just prior to collection time most likely accounts for much of the difference in richness at SCP from 1999 to 2000 (Table 2, Fig. 6). In spite of fewer plots and the lack of moisture, the larger plots show richness nearly equal to that from 1999 at SCP. Spring Creek Prairie had higher total species richness for all classes of vegetation in the spring of 2000 (Table 2). It should be noted that at NMP, five of the plot locations were burned just two weeks prior to data collection time which reduced the number of plant species actively growing (Table 3). Twice as many species were recorded in unburned vs. burned plots at NMP. Burned plots at NMP presented an average of 13 species per 1 x 10 m plot and 19 species in 10 x 10 m plots. Unburned plots averaged 15.5 species per plot in the smaller plots and 28.5 per plot in the larger plots. Average richness totals per plot in the 10 x 10 m plots was 19 in the burned plots and 28.5 in the unburned plots.
Abundance of forbs and shrubs
Abundance sampling at SCP in the spring and again in the fall showed the most common species in the spring to include more of both introduced ruderal species and competitive species of the dominant tallgrass prairie matrix (Table 4). Listing these species with their respective conservatism value presents a picture of the floristic quality of the sample sites. Solidago species that were difficult to identify in the spring were combined and given a C value of 4, which is the average C value of Solidago species found at SCP. Average C values did not differ greatly from spring to fall at SCP.
Fall data from 1999 indicated that the 20 most abundant forb species varied between prairies, as did the average number of forbs and shrubs per plot (Table 5). Ambrosia psilostachya (western ragweed) was the most abundant species regardless of management regime. Ruderal species at SCP, such as Convolvulus arvensis (bindweed), Medicago lupulina (black medic), Trifolium pratense (red clover), and Trifolium repens (white clover) are not present in samples taken at NMP. Also conspicuous is the absence of Helianthus spp. (sunflowers) at SCP. Richness of upland species was significantly different between the two prairies, as was abundance of ruderal Species. The abundance of ruderal species (C values < 4) versus competitive and late-seral species (C values > 3) at SCP was significantly higher than those at NMP (p < 0.05).
The forbs and woody species from the fall 1999 data were divided into the following vegetation categories for further analysis: introduced ruderal forbs (IRF), introduced ruderal woody species (IRW), native ruderal forbs (NRF), native ruderal woody species (NRW), native dominant matrix forbs (NDF), native dominant matrix woody species (NDW), and native late-seral forbs (NLF). Examples of IRF species included Convolvulus arvensis (field bindweed), Medicago lupulina (alfalfa), Trifolium pratense (red clover), and Trifolium repens (white clover). The only IRW was Rosa multiflora (multiflora rose). The most common NRF species are Ambrosia psilostachya (western ragweed), Vernonia baldwinii (western ironweed), Achillea millefolium (yarrow), and Oxalis dillenii (woodsorrel). Symphoricarpos orbiculatus (coralberry) and Gleditsia triacanthos (honeylocust) were the NRW species. Competitive forbs of the native dominant matrix (NDF) included Aster ericoides (heath aster), Helianthus rigidus (stiff sunflower), Monarda fistulosa (beebalm), and Salvia azurea (Pitcher's sage) among others. Amorpha canescens (leadplant) and Cornus drummondii (gray dogwood) were representative of NDW species. Native late-seral forbs were represented by only two species in these plots: Solidago speciosa (showy goldenrod) from NMP and Desmodium illinoense (Illinois tickclover) from SCP. The abundance of each vegetation class for each plot is shown in Table 6.
These seven vegetation classes were analyzed using Detrended Correspondence Analysis (DCA) (McCune and Mefford 1995). Table 7 lists the vegetation class scores for axes one, two, and three. The first axis separates native dominant and late seral species plots, at the positive end of the axis, from introduced ruderal species plots at the negative end of the axis and native ruderals at just above zero (Fig. 8). On this axis, vegetation data from NMP plots dominate the upper end of the axis. The second axis places introduced species in the upper end of the scale and native species in the middle and lower end of the axis. On this axis vegetation data from SCP plots tend to cluster near native ruderal forbs, while data from NMP plots are closer to native dominant forbs. Axis three shows all plot data clustered around native ruderal and native dominant forbs along with introduced ruderal woody species (Fig. 9). The plots are shown to be far removed from the native late-seral forbs at the low end of the scale and somewhat closer to native ruderal and dominant woody species at the upper end of the scale.
[FIGURES 8-9 OMITTED]
Plots used for comparison between the two prairies contained four soil types in common. When soil type was added to the plot labels, none of the four soil types were found to group together. In other words, the four soil types could be found in all areas of the graph. Therefore, no particular soil type was likely to hold any particular vegetation class.
Data from all 48 plots at SCP from the fall of 1999 were compared to see if any patterns could be found among plots in the different pastures. The resulting analysis showed a cluster of nearly all plots around native ruderal forbs (NRF) on all axes (Figs. 10, 11). The few exceptions, though still very close to the original group, were plots 14, 27, 46, 51, and 62. Plot 14 was not particularly noteworthy except that it contained a few plants of Desmodium illinoensis (Illinois tickclover), which is in the native late-seral category. Plot 27 comes from an area that is fairly flat and devoid of Gleditsia triacanthos (honeylocust) and, therefore, has often been hayed. Vegetation data from other plots in that area did not show divergence from the rest of the data. Plot 46 is in a very extensively grazed area and contains mostly introduced ruderal forbs. Plot 51 data gravitate toward the native dominant woody species because it contains a patch of Symphoricarpos orbiculatus (coralberry). Plot 62 is located in a fenced area too small to be grazed by very many cattle for a long period. It is also an area that is possibly the richest and most diverse of all upland sites at SCP. Vegetation data from plot 62 tend to follow NDF on all axes.
[FIGURES 8-9 OMITTED]
Frequency of grasses and grass-like plants
Frequencies of warm-season grasses indicated higher values for Bouteloua curtipendula (sideoats grama), Schizachyrium scoparium (little bluestem), and Sporobolus asper (tall dropseed) at SCP than at NMP (Table 8). Andropogon gerardii (big bluestem), Sorghastrum nutans (Indiangrass), and Panicum virgatum (switchgrass) were more frequent at NMP than at SCP.
Frequencies of cool-season grasses were recorded for all 48 SCP plots in June of 1999. The results show Poa pratensis (Kentucky bluegrass), Bromus inermis (smooth brome), and Dichanthelium oligosanthes (Scribner's panicum) to be the most frequent cool-season grasses, with 89%, 70%, and 41% frequency respectively. Frequencies of cool-season grasses were again collected from NMP and SCP on each of nine 10 x 10 m plots in the spring of 2000 (Table 9). Smooth brome was twice as frequent in the SCP plots as in the NMP plots, with 89% frequency. Bromus japonicus (Japanese brome) was also prevalent at SCP, but it was not recorded in the plots at NMP. This would be consistent with grazed versus burned management regimes, where spring burns would tend to decrease cool-season species. Both Dichanthelium acuminatum (dichanthelium) and Stipa spartea (porcupine grass) are listed as late seral species for Nebraska that are not well adapted to disturbance (Rolfsmeier and Steinauer, unpublished). In spite of spring burns, these species had greater abundance under the burn management at NMP than the grazing regime at SCP.
Floristic quality index
Frequency data were also used along with values of conservatism (C values) to determine the floristic quality indexes for both prairies according to the Chicago Method (Wilhelm and Masters 1995). Values of conservatism are listed for all species in Appendices A and B. Floristic quality indexes were computed from the entire species list for both prairies as a whole, on the upland prairie species from the species list, and on the species list from sampled plots. Average C values for native-only and for native and exotic species, and an FQI value for native-only species are given in all instances.
Tables 10 and 11 list average C and FQI values for the 17 SCP plots and the nine NMP plots that were compared because of their similarity in soil type. Average C and FQI values are higher for NMP than for SCP. When FQI for native species is compared, the difference is only about 2 points. Both prairies had FQI values in the lower twenties. In a sample study done by Rolfsmeier and Steinauer (unpublished), a single 10 x 10 m plot at two different prairies gave FQI (native only) values of 32.5 for Schneekloth Prairie (another tallgrass prairie in eastern Nebraska) and 17.8 at Nine Mile Prairie. Wilhelm and Masters (1995), in reference to Illinois prairies, said that areas with average C and FQI values of 3.5 and 35 or higher, respectively, had marginal conservatism value. Indexes of 50 or higher were rare. Average conservatism value for native species at NMP reached exactly 3.5 in fall 1999 data (Table 10). Spring Creek Prairie fell short of these recommended values with an average C value of 2.98 (Table 11).
The list of total vegetation yields FQI values, for native species, of 63.71 and 52.97 for NMP and SCP respectively (Table 12). These total-vegetation FQI values cannot be compared to the suggested conservatism values by Wilhelm and Masters (1995) because these data include wetland and wooded riparian vegetation habitats. Average C values may be of more use when comparing a diverse range of habitats. Total upland species provided FQI values of 49.21 and 39.97 respectively. When compared to C values from plot data, the use of total upland and total species lists slightly reduced the average C value at NMP. Again, these values cannot be used to compare with prairies in which the vegetation has only been sampled but have no total population count. These values can, however, provide some insight into the two prairies in question. In addition, they provide a look at the proficiency of the 'Chicago Method' in assessing the value of prairie ecosystems. Perhaps these values represent the true value of these prairies or at least the potential value in terms of represented species, if not abundant species.
Data gathered in 2000 were collected in such a way that comparisons could be made between floristic quality using both the smaller 1 x 10 m plots as well as the larger 10 x 10 m plots. Average C values increased slightly with larger sampling plots at both SCP and NMP (Table 13). While sample size made a difference in the FQI at NMP, it did not seem to make a difference in the average C value. Floristic Quality Index values rely heavily on richness (Francis et al. 2000). Average C values between NMP and SCP are very close. In spite of that, FQI was larger at NMP in all cases. This can be explained by the richness factor. Nine-Mile Prairie has more individuals of most species throughout the prairie and, therefore, more evenness. This should translate into a higher diversity measure as well.
Richness and measures of richness such as the Chicago method give an indication of the value of conservation sites, but other measures are useful additions to these measures. Abundance data, such as was collected at NMP and SCP, can be included with richness measures in diversity measurement. Simpson's diversity index (SDI) was used to calculate diversity for each site. Table 14 summarizes Simpson's index values for each sample location and time. Simpson's index values indicate greater diversity at NMP when adjusting for sample size and soil type (using the 17 plots at SCP and 9 at NMP for the same number of plots per acre). Both FQI and Simpson's index rely heavily on richness, and therefore both measures increase with sample size. Simpson's index requires a measure of abundance, and therefore only forbs and woody species were used for comparison between the two prairies. The reciprocal value of the index increases with increasing diversity. At NMP, a diversity index of 0.17 was calculated with a reciprocal of 5.77. At SCP the 17 plots of like-soil type produced a value of 0.24 with a reciprocal of 4.18. Since more plot data were available for SCP, the index was applied to all 48 plots for further comparison. These plots yielded an SDI of 0.23 with a reciprocal of 4.30. These extra plots only increased the diversity measure by 0.12. The increase is somewhat larger when comparing the NMP diversity values with that of SCP. However, two-sample t-tests showed no significant differences in SDI values among these plots (p > 0.05).
Basal area and density of grasses and sedges
Basal area recorded for both prairies was analyzed according to vegetation classes (cool- and warm-season grasses and sedges) and C value (introduced ruderal, native ruderal, native competitive dominant matrix species, and native late seral species). This gave the following classes of grasses and sedges: cool-season introduced ruderal grasses (CIR), cool-season native dominant grasses (CND), warm-season native ruderal grasses (WNR), warm-season native dominant grasses (WND), warm-season native late-seral grasses (WNL), and cool-season native dominant sedges (CNDS). There were no cool-season native introduced grasses, no warm-season introduced ruderal grasses, and no cool-season native late-seral grasses or sedges recorded among the samples. Examples of species in each of these vegetation classes are listed in Table 15. These classes were then analyzed using Detrended Correspondence Analysis (DCA) (McCune and Mefford 1995). Table 16 lists the scores for each of the first three axes. Ecological gradients shown by the scores of the first axis show the most negative association on axis one to be WNL and CNDS and the most positive association with WNR species. In general, native dominants and late-seral species have a negative association and ruderal species have a positive association with axis one. Axis two has a strong positive association with late-seral species. Native ruderal grasses have the most negative association with axis two. Axis three is negatively associated with cool-season native dominant grasses and most positively with native late-seral grasses and cool-season sedges. Caution is advised when assessing the information from the graphs. For instance, the data appear to have a strong relationship to CND on axes one and two (Fig. 12). Remembering that this is a three-dimensional graph, axis three reveals that CND is really relatively far removed from the data (Fig. 13). The data from the plots tend to cluster more closely to WND (especially NMP data) and CIR (especially SCP data).
[FIGURES 12-13 OMITTED]
In figure 12, data from NMP dominate the lower left side, indicating a greater predominance of warm-season native dominant grasses on axis one and warm-season native dominant and ruderal grasses as well as sedges on axis two. The second axis is most negatively associated with warm-season natives and positively with cool-season species. This shows that NMP has the greater component of warm-season native grasses. Spring Creek Prairie holds the greatest association to cool-season introduced ruderal species on the first axis. Data from both prairies are spread across the second axis with SCP showing the heaviest concentration of cool-season native dominant and introduced ruderal grasses. This supports the presupposition that SCP, which has not had more than one scheduled burn prior to 1998, would have the greater abundance of cool-season grasses.
The third axis most negatively associates with cool-season native dominant matrix grasses and most positively with warm-season late-seral grasses and cool-season sedges. The only warm-season native late seral grass found in the plots was Sporobolus heterolepis (prairie dropseed), which was recorded only at NMP. While it occurs at SCP, it was not represented in any of the plots. The data from plots at the upper end of axis three represent both cool- and warm-season native dominant grasses. Warm-season native dominants are represented in the bulk of the plots near the midpoint of axis three.
As was done with the forbs, soil types were included on graphs for each of these plots. These graphs are not shown here because the added letters make them difficult to read. The four soil types are scattered among the points on the graph showing no distinct grouping or association to any particular vegetation class. This further supports the indication that management practices, rather than soil-type has lead to the differences between the two prairies in dominant vegetation types.
Basal-area data for grasses from all 48 plots from SCP were also analyzed using DCA. This time, only four vegetation classes were used because cool-season dominant and warm-season late seral grasses were not recorded in any SCP plots. The four remaining classes tend to separate into their own quadrats on the resulting graph (Fig. 14). Plots from pasture three (numbers 31-38) tend toward the negative side of axis one, where ruderal species are predominant. Figure 15 shows data from pasture three clustering near cool-season introduced ruderals. Generally, all plots fit somewhere between cool-season introduced ruderals and warm-season native dominants and are removed from warm-season native ruderals and sedges.
[FIGURES 14-15 OMITTED]
CONCLUSIONS AND RECOMMENDATIONS
First observations of SCP in 1998 indicated a species-poor condition. One-hundred years of grazing, with suspected periods of improper grazing, had provided much opportunity for invasive weedy species. The more competitive dominant forb species did not appear to be abundant. The prognosis was not good. The results of two years of data and specimen collection have validated much of that prognosis but with some unanticipated deviations. The property is relatively large, as compared with other remnant native tallgrass prairies in southeastern Nebraska. Two-hundred and forty-seven hectares (610 acres) of rolling hills, uplands, lowlands, wetlands, ponds, and wooded riparian areas provide a variety of habitats and tepographic diverstiy in which a wide variety of plants persist. While the uplands are indeed rich in introduced species, many plants of the dominant tall-grass prairie matrix (and even a few late seral species) can still be found. The new prognosis is cautiously hopeful. Since these species are present, perhaps they can be encouraged to increase. In some cases, the seed bank may help with recovery. However, even though more species have been found than was expected, many are weedy invasive species.
There are fewer species per land unit area at SCP than at NMP, and abundances of dominant-matrix and late-seral forb species are low. In upland species alone, SCP is species-poor when compared to the smaller NMP. Spring Creek Prairie, with an area three times the size of NMP, would be expected have at least slightly more species than NMP. In fairness though, there were only 345 species recorded for NMP by Steiger (1930) when it was originally studied as a 323-ha (800 acre) prairie. The 392 species recorded included 62 species from Steiger's list that were found nearby in 1987, but not in the smaller 97-ha (240 acre) remaining prairie proper. Additional species will almost certainly be discovered at SCP. The opportunity to view different areas of the prairie under different conditions at different times of the year is being provided by changes in management practices, fewer cattle, prescribed burns, fewer ruderal trees, and changes in weather patterns. These factors, along with more frequent visitation by the general public and the scientific community, will provide opportunity for additional species to be discovered.
Results of ordination of data according to soil types showed no evidence that soil types were associated with the variation in the occurrence or abundance of vegetation classifications. It may thus be concluded that the management practices had more to do with the abundance of vegetation classes at either prairie than did soil type. Forb data from the two sites did tend to separate with regard to dominant native and ruderal species. Ruderal species were more closely associated with the SCP plots. Native, warm-season grass data associated more closely with NMP than SCP plots. These results are supported by abundance and frequency data. Spring burning at NMP supported dominating warm-season grasses. Grazing at SCP provided opportunities for invasive and ruderal species.
The original 1 x 10 m plots were more practical and sufficient for abundance measures. Species counts within the larger plots (10 x 10 m) would have been impractical, however, I would recommend the larger plot size for frequency counts used for C and FQI values. The larger plots provided higher species richness and C and FQI values with fewer plots. More small plots were required for the same results. Average C values based on total vegetation counts were also helpful in analyzing the site. This may be a more accurate assessment of potential for prairie restoration. It included nearly 100 additional upland species that were not found in the plots. Repeating such counts is not always practical, so smaller samples of the population are also necessary for future comparisons. None of these measures is sufficient when used exclusively. Average C and FQI values alone do not account for abundance or diversity. Diversity measures are necessary in assessing the condition of prairie vegetation where evenness of species on a site is concerned.
Average C values, FQI values, and diversity measures were lower for SCP than for NMP in all tests. The degree of difference in average C and FQI values was not great. The differences became more apparent when abundance was included in Simpson's diversity index. A greater abundance of ruderal species that was apparent during the original visual inspection was later proven statistically. The magnitude of the invasion of exotic species in abundance may serve to slow the recovery. Other studies have shown that prescribed burning does tend to decrease exotic forbs and grasses and increase native warm-season grasses. Care should be taken, however, to avoid reduction of the native cool-season grasses and forbs that can still be found at SCP.
Each of these prairies represents what happens when only one management scheme or land use is practiced for many years. Continued use of singularity in management practices will only serve to select for species tolerant of such practices. Management plans for SCP call for decreased stocking-rates of cattle and the resting of each pasture from grazing for one year or slightly more, with prescribed burns included in that resting time. In some areas, seeding or plantings may be required to hasten recovery.
Collins (in Kaiser 1998) said that grazing--even by bison--can be detrimental to already degraded grasslands. He recommends moderate grazing on healthy prairies. The next step is to provide definitions of "moderate grazing" and "healthy prairie'. Floristic quality indexes, along with diversity indexes, might provide one way to define a healthy prairie. The definition of "moderate grazing" is somewhat nebulous. Prairie managers, researchers, and ranchers could benefit from a clear definition. It would also be wise for publishers of diversity studies to include stocking rates in their reports of diversity under grazing situations. Most of the available literature reporting the effects of defoliation and regrowth refer to grasses and a few legumes. As restoration projects become more common, there is a need for studies on the effects of defoliation on more prairie forbs. Further studies at SCP can be done to evaluate the recovery of forbs and grasses by comparing the data presented in this study to future data. The herbarium collection can like-wise be used to confirm the identity of species present and additional species as they are discovered.
Appendix 1: Species List for Spring Creek and Nine-Mile prairies. A = annual. Anth = season of anthesis. B = biennial, Coeff = coefficint of conservatism (Steinauer and Rolfsmeier, unpublished), D = distributed areas in upland, F = fall, I = introduced, Loc = location, N = native, NM = Nine-Mile Prairie only, P = perennial only, Prov = provenance, Q = submersed aquatics, R = wooded ravines, S = shrubs, SC = Spring Creek Prairie only, Sp = spring, Su = summer, U = upland, W = wetland, SC/NM = both Nine-Mile and Spring Creek prairies. FAMILY Species Loc Coeff Prov Habit Habitat Anth ACANTHACEAE Ruellia humilis L. SC/NM 4 N P U Su ACERACEAE Acer negundo L. SC/NM 1 N T R Sp ALISMATACEAE Alisma triviale Pursh NM 4 N P W Su Echinodorus rostratus (Nutt.) Engelm. NM 6 N A W Su Sagittaria calycina Engelm. SC/NM 3 N P W SuF Sagittaria latifolia Willd. SC 5 N P W SuF AMARANTHACEAE Amaranthus albus L. NM 0 N A D SuF Amaranthus retroflexus L. SC/NM 0 N A D SuF Amaranthus rudis Sauer SC/NM 0 N A W Su ANACARDIACEAE Rhus glabra L. SC/NM 1 N P U Su Toxicodendron radicans (L.) O. Ktze SC/NM 2 N P R Su APIACEAE Cicuta maculata L. NM 5 N P W Su Conium maculatum L. SC/NM I B R Su Lomatium foeniculaceum (Nutt.) Coult. & Rose SC/NM 6 N P U Sp Sanicula canadensis L. SC/NM 2 N B R Su Sanicula gregaria Bickn. NM N B R SpSu APOCYNACEAE Apocynum cannabinum L. SC/NM 1 N P W Su ASCLEPIADACEAE Asclepias incarnata L. SC/NM 4 N P W Su Asclepias lanuginosa Nutt. NM 8 N P U Su Asclepias stenophylla A. Gray SC/NM 6 N P U Su Asclepias sullivantii Engelm. NM 7 N P U Su Asclepias syriaca L. SC/NM 0 N P U Su Asclepias tuberosa L. SC/NM 6 N P U Su Asclepias verticillata L. SC/NM 2 N P U Su Asclepias viridiflora Raf. SC/NM 5 N P U Su Asclepias viridis Walt. SC/NM 4 N P U Su ASTERACEAE Achillea millefolium L. SC/NM 2 N P U Su Ambrosia artemisiifolia L. SC/NM 0 N A D SuF Ambrosia psilostachya DC. SC/NM 1 N P U SuF Ambrosia trifida L. SC/NM 0 N A D SuF Antennaria neglecta Greene SC/NM 1 N P U SpSu Arctium minus Bernh. SC/NM I B D SuF Artemisia dracunculus L. NM 3 N P U SuF Artemisia ludoviciana Nutt. SC/NM 4 N P U SuF Aster ericoides L. SC/NM 4 N P U F Aster oblongifolius Nutt. NM 5 N P U F Aster sericeus Vent. SC/NM 7 N P U F. Aster simplex Willd. SC/NM 2 N P U/R F Bidens cernuus L. SC/NM 3 N A W F Bidens connatus Muhl. ex Willd. SC 3 N A W F Bidens frondosus L. SC/NM 1 N A W F Bidens vulgatus Greene SC/NM 1 N A W F Cacalia plantaginea (Raf.) Shinners SC/NM 7 N P U Su Carduus nutans L. SC/NM I B D Su Cichorium intybus L. SC I P D SuF Cirsium altissimum (L.) Spreng. SC/NM 0 N P U SuF Cirsium flodmanii (Rydb.) Arthur SC/NM 3 N B U Su Cirsium undulatum (Nutt.) Spreng. SC/NM 4 N P U Su Cirsium vulgare (Savi) Ten. SC I B U SuF Conyza candensis (L.) Cronq. SC/NM 0 N A D SuF Conyza ramosissima Cronq. SC/NM 0 N A D SuF Dyssodia papposa (Vent.) Hitchc. SC/NM 0 N A D SuF Echinacea angustifolia DC. SC/NM 5 N P U Su Eclipta prostrata (L.) L. SC/NM 2 N A W SuF Erechtites hieraciifolia (L.) Raf. ex DC. SC/NM 0 N A W F Erigeron philadelphicus L. SC 4 N B U Su Erigeron strigosus Muhl. ex Willd. SC/NM 2 N A U Su Eupatorium perfoliatum L. NM 5 N P R SuF Eupatorium rugosum Houtt. SC/NM 4 N P R SuF Euthamia gymnospermoides Greene NM 4 N P U SuF Gnaphalium obtusifolium L. SC 3 N B U SuF Grindelia squarrosa (Push) Dun. SC/NM 0 N P D SuF Helianthus annuus L. SC/NM 0 N A D SuF Helianthus grosseserratus Martens SC/NM 3 N P U F Helianthus maximilianii Schrad. NM 4 N P R F Helianthus rigidus L. SC/NM 5 N P U SuF Helianthus tuberosus L. SC/NM 3 N P U SuF Heliopsis helianthoides (L.) Sweet SC/NM 5 N P U Su Hieracium longipilum Torr. SC/NM 6 N P U Su Kuhnia eupatorioides L. SC/NM 4 N P U SuF Lactuca canadensis L. SC/NM 2 N B R SuF Lactuca ludoviciana Nutt. NM 3 N B U SuF Lactuca oblongifolia Nutt. SC/NM 0 N P U SuF Lactuca saligna L. SC I A U Su Lactuca serriola L. SC/NM I B D SuF Liatris aspera Michx. SC/NM 7 N P U SuF Liatris punctata Hook. SC/NM 5 N P U SuF Lygodesmia juncea Hook. NM 3 N P U Su Matricaria matricarioides (Less.) Porter SC I A D Sp Microseris cuspidata (Push) Sch.-Bip. SC/NM 6 N P U Sp Prenanthes aspera Michx. SC/NM 8 N P R SuF Ratibida columnifera (Nutt.) Woot. & Standl. SC/NM 4 N P U Su Rudbeckia hirta L. SC/NM 2 N P U Su Rudbeckia laciniata L. SC/NM 4 N P R Su Senecio integerrimus Nutt. NM 5 N P U Sp Senecio plattensis Nutt. SC/NM 4 N B U Sp Silphium integrifolium Michx. SC/NM 4 N P U Su Silphium perfoliatum L. SC/NM 4 N P R Su Solidago canadensis L. SC/NM 2 N P U F Solidago gigantea Ait. NM 3 N P U F Solidago missouiensis Nutt. SC/NM 5 N P U F Solidago nemoralis Ait. NM 4 N P U F Solidago rigida L. SC/NM 3 N P U F Solidago speciosa Nutt. NM 7 N P U F Sonchus asper L. SC/NM. I A U F Taraxacum officinale Weber SC/NM I P D SpF Tragopogon dubius Scop. SC/NM I B D Su Tragopogon pratensis Scop. NM I B D SpSu Vernonia baldwinii Torr. SC/NM 3 N P U Su Xonthium strumarium L. NM 0 I A U SuF BIGNONIACEAE Catalpa speciosa Warder SC I P R Sp BORAGINACEAE Hackelia virginiana (L.) I.M. Johnst. SC/NM 2 N B R SuP Lappula echinata Gilib. NM I A D SpF Lithospermum canescens Lehm. NM 5 N P U SpSu Lithospermum incisum Lehm. SC/NM 5 N P U SpSu BRASSICACEAE Arabis hirsuta (L.) Scop. NM 5 N B R Sp Brassica kaber (DC.) Wheeler NM I B D Su Brassica napus L. NM I B D SuF Barbarea vulgaris R. Br. SC I B D Sp Camelina sativa Andrz. NM I A D Sp Capsella bursa-pastoris (L.) Medic. SC/NM I A D Sp Cardaria draba (L.) Desv. SC/NM I P D Sp Chorispora tenella (Pall.) DC. SC I A D Sp Descurainia pinnata (Walt.) Britt. SC 0 N A D SpSu Draba reptans (Lam.) Fern. SC/NM 3 N A D Sp Erysimum asperum (Nutt.) DC. SC 4 N P D SpF Erysimum repandum L. SC I A D Sp Lepidium densiflorum Schrad. SC/NM 0 N A D SuF Lepidium virginicum L. NM 0 N A D SuF Rorippa palustris (L.) Bess. SC/NM 4 N B W Su Sisymbrium loeselii L. SC I A D SpSu Thlaspi arvense L. SC/NM I A D Sp CAESALPINIACEAE Cassia chamaecrista L. SC/NM 1 N A D SuF Cassia marilandica L. NM 5 N P R SuF Gleditsia triacanthos L. SC/NM 1 N T R Sp CAMPANULACEAE Campanula americana L. NM 4 N A R SuF Lobelia siphilitica L. SC/NM 6 N P W SuF Triodanis leptocarpa (L.) Nieuw. NM 3 N A D SpSu Triodanis perfoliata (L.) Nieuw. SC/NM 2 N A D SpSu CANNABACEAE Cannabis sativa L. SC/NM I A D SuF Humulus lupulus L. NM 3 N P R Su CAPRIFOLIACEAE Sambucus canadensis L. SC/NM 2 N S R Su Symphoricarpos occidentalis Hook. SC/NM 2 N S U Su Symphoricarpos orbiculatus Moench SC/NM 2 N S R Su CARYOPHYLLACEAE Cerastium brachypodum (Engelm. ex A. Gray) NM 1 N A D SpSu Dianthus armeria L. SC I AB D SpSu Silene antirrhina L. SC/NM 2 N A D Su Silene stellata L. NM 6 N P R Su Stellaria pallida (Dumort.) Pire SC I A D SpF CELASTRACEAE Celastrus scandens L. SC/NM 4 N V R SpSu CERATOPHYLLACEAE Ceratophyllum demersum L. SC 4 N Q SpSu CHENOPODIACEAE Chenopodium album L. SC I A D SuF Chenopodium berlandieri Moq. SC/NM 0 N A D SuF Chenopodium missouriense Aellen SC 0 N A U F Chenopodium pratericola Rydb. SC 1 N A D Su Chenopodium simplex (Torr.) Raf. SC 1 N A W Su Chenopodium standleyanum Aellen SC 4 N A W Su Chenopodium strictum Roth SC 0 N A D F Kochia scoparia (L.) Schrad. NM I A D SuF Salsola iberica Senn. & Pau NM I A D SuF CLUSIACEAE Hypericum perforatum Lam. SC I P U Su COMMELINACEAE Tradescantia bracteata Small SC/NM 5 N P U Su CONVOLVULACEAE Calystegia sepium (L.) R.Br. SC/NM 1 N P R SuF Convoloulus arvensis L. SC/NM I P D SpF CORNACEAE Cornus drummondii D. A. Mey. SC/NM 3 N S R SpSu CRASSULACEAE Penthorum sedoides L. SC/NM 4 N P W SuF CUCURBITACEAE Echinosystis lobata (Michx.) T. & G. NM 3 N A R SuF Sicyos angulatus L. SC/NM 1 N A R SuF CUPRESSACEAE Juniperus virginiana L. SC/NM 0 N T U Sp CUSCUTACEAE Cuscuta coryli Engelm. NM 5 N A U F Cuscuta glomerata Choisy NM 6 N A U SuF Cuscuta pentagona Engelm. NM 0 N A U Su Cuscuta polygonorum Engelm. SC 3 N A D SuF CYPERACEAE Carex bicknellii Britt. SC/NM 6 N P W SpU Carex blanda Dew. SC 2 N P RW Sp Carex brevior (Dew.) Mack. ex Lunell SC/NM 3 N P RW Sp Carex emoryi Dew. SC/NM 6 N P W SpSu Carex gravida Bailey SC/NM 4 N P W SpSu Carex grisea Wahl. SC/NM 3 N P W Sp Carex heliophila Mack. SC/NM 5 N P U SpSu Carex hystericina Muhl. ex Willd. SC/NM 6 N P UW SpSu Carex laeviconica Dew. NM 1 N P W SpSu Carex lanuginosa Michx. NM 4 N P W SpSu Carex meadii Dew. SC/NM 1 N P U SpSu Carex stipata Muhl. ex Willd. SC/NM 4 N P W SpSu Carex vulpinoidea Michx. SC/NM 4 N P W SpSu Cyperus esculentus L. NM 0 N P R SuF Cyperus erythrorhizos Muhl. SC 4 N A W F Cyperus lupulinus (Spreng.) Marcks NM 3 N P U SuF Cyperus xmesochoreus Muhl. NM 3 N P D SuF Cyperus odoratus L. SC/NM 3 N A W SuF Cyperus schweinitzii Torr. SC 4 N P W SuF Cyperus strigosus L. SC 4 N P W SuF Eleocharis erythropoda Steud. SC/NM 5 N P W Su Eleocharis macrostachya Britt. NM 4 N P W Su Schoenoplectus pungens (Vahl.) Pallas SC/NM 4 N P W SuF Schoenoplectus tabernaemontanii (Gmel.) Pallas SC/NM 5 N P W SuF Scirpus atrovirens Willd. SC/NM 4 N P W SuF Scirpus pallidus (Britt.) Fern. SC/NM 4 N P W Su ELAEAGNACEAE Elaeagnus angustifolia L. SC I T R Sp EQUISETACEAE Equisetum arvense L. SC/NM 4 N P W Sp Equisetum huemale L. NM 4 N P W Su Equisetum laevigatum A. Br. SC/NM 4 N P R SpSu Equisetum xferrisii Clute SC 4 N P R SpSu EUPHORBIACEAE Acalypha rhomboidea Raf. SC/NM 0 N A R SuF Acalypha virginica L. NM 2 N A R SuF Euphorbia corollata L. NM 3 N P U SuF Euphorbia cyathophora Murray SC 3 N A D SuF Euphorbia dentata Michx. SC/NM 0 N A D SuF Euphorbia maculata L. SC/NM I P U SpSu Euphorbia marginata Pursh SC/NM 0 N A D SuF Euphorbia nutans Lag. SC/NM 0 N A D SuF FABACEAE Amorpha canescens Pursh SC/NM 6 N S U Su Amorpha fruticosa L. SC/NM 5 N S W Su Amphicarpaea bracteata (L.) Fern. SC/NM 4 N A R SuF Astragalus canadensis L. SC/NM 7 N P U Sp Astragalus crassicarpus Nutt. SC/NM 7 N P U Sp Astragalus plattensis Nutt. NM 7 N P U SpSu Baptisia bracteata Muhl. ex Ell. SC/NM 6 N P U Sp Dalea candida Michx. ex Willd. SC/NM 6 N P U Su Dalea purpurea Vent. SC/NM 6 N P U Su Desmodium canadense (L.) DC. SC/NM 5 N P U Su Desmodium illinoense A. Gray SC/NM 7 N P U Su Glycyrrhiza lepidota Pursh SC/NM 4 N P U Su Lespedeza capitata Michx. SC/NM 6 N P U SuF Lespedeza cuneata (Dumont) G. Don NM I P U SuF Lespedeza stipulacea Maxim. SC I P U SuF Lotus purshianus (Benth.) Clem. & Clem. SC 3 N A U SpF Medicago lupulina L. SC/NM I A D SuF Medicago sativa L. SC/NM I P D SpF Melilotus albus Medic. SC/NM I B D SpF Melilotus officinalis (L.) Pall. SC/NM I B D SpF Psoralea argophylla Pursh SC/NM 6 N P U Su Psoralea esculenta Pursh SC/NM 8 N P U Su Psoralea tenuiflora Pursh SC/NM 5 N P U Su Robinia pseudo-acacia L. SC I P R Sp Strophostyles leiosperma (T. & G.) Piper SC 4 N A U SpF Trifolium pratense L. SC/NM I P D SpF Trifolium repens L. SC/NM I P D SpF Vicia americana Muhl. NM 6 N P U SpSu Vicia villosa Roth SC I A D SpSu FAGACEAE Quercus macrocarpa Michx. SC 5 N P R Sp FUMARIACEAE Corydalis micrantha (Engelm.) A. Gray NM 0 N A U SpSu GENTIANACEAE Geniana puberulenta Pringle NM 7 N P U F GROSSULARICACEAE Ribes missouriense Nutt. SC/NM 4 N S R Sp HYDROPHYLLACEAE Ellisia nyctelea L. SC/NM 0 N A R Sp IRIDACEAE Sisyrinchium campestre Bickn. SC/NM 4 N P U Sp JUGLANDACEAE Juglans nigra L. SC 5 N P R Sp JUNCACEAE Juncus dudleyi Wieg. NM 5 N P W Su Juncus interior Wieg. SC/NM 4 N P W Su Juncus torreyi Cov. NM 4 N P W SuF LAMIACEAE Agastache nepetoides (L.) O. Ktze SC 5 N P R SuF Hedeoma hispidum L. SC/NM 1 N A U SpSu Lamium amplexicaule L. SC I A D SpF Leonurus cardiaca L. SC I P D Su Lycopus americanus Muhl. ex Bart. SC/NM 5 N P W SuF Mentha arvensis L. SC/NM 5 N P W SuF Monarda fistulosa L. SC/NM 4 N P U Su Nepeta cataria L. SC/NM I P D SuF Salvia azurea Lam. SC/NM 6 N P U F Scutellaria lateriflora L. NM 5 N P W Su Scutellaria parvula Michx. SC/NM 4 N P U Su Stachys palustris L. NM 5 N P W Su Teucrium canadense L. SC/NM 4 N P R Su LEMNACEAE Lemna minor L. SC/NM 5 N P Q Su Spirodela polyrrhiza (L.) Schleid. SC 6 N P Q Su Wolffia columbiana Karst. SC 5 N P Q Su LILIACEAE Allium canadense L. lavendulare (Bates) M.Ownbey SC/NM 7 N P U Su Allium canadense L. var. canadense SC/NM 1 N P U Su Asparagus officinalis L. SC/NM I P U Sp Polygonatum biflorum (Walt.) Ell. SC/NM 4 N P R Su Smilacina stellata (L.) Desf. NM 4 N P R SpSu LINACEAE Linum sulcatum Ridd. SC/NM 6 N A U Su LYTHRACEAE Ammannia robusta Heer & Regel. SC/NM 5 N A W SuF Lythrum alatum Pursh NM 6 N P W SuF MALVACEAE Abutilon theophrasti Medic. SC/NM I A D SuF Callirhoe alcaeoides (Michx.) A. Gray NM 6 N P U Su Callirhoe involucrata (T.&G.) A. Gray SC/NM 1 N P U SpSu Hibiscus trionum L. SC I A D Su Malva rotundifolia L. SC I A D Su MENISPERMACEAE Menispermum canadense L. SC/NM 5 N V R Su MIMOSACEAE Desmanthus illinoensis (Michx.) SC/NM 5 N P U Su MOLLUGINACEAE Mollugo verticillata L. SC I A D SuF MORACEAE Maclura pomifera (Raf.) Schneid. NM I T R Sp Morus alba L. SC/NM I T U Sp NAJADACEAE Najas guadalupensis (Spreng.) Magnus NM 6 N A Q SuF NYCTAGINACEAE Mirabilis hirsuta (Pursh) MacM. NM 5 N P U Su Mirabilis linearis (Pursh) Heimerl. NM 5 N P U Su Mirabilis nyctaginea (Michx.) MacM. SC/NM 0 N P U Su OLEACEAE Fraxinus pennsylanvica Marsh. SC/NM 2 N T R SP ONAGRACEAE Calylophus serrulatus (Nutt.) Raven SC/NM 5 N P U Su Epilobium coloratum Biehler SC/NM 5 N P W SuF Gaura longiflora Spach SC/NM 2 N B D SuF Gaura parviflora Dougl. SC/NM 0 N B D SpSu Oenothera villosa Thunb. SC/NM 1 N B D SuF ORCHIDACEAE Cypridpedium candidum Muhl. ex Willd. NM 10 N P W SpSu Habenaria leucophaea (Nutt.) A. Gray NM 9 N P W Su Spiranthes cernua (L.) Rich. SC/NM 7 N P U F Spiranthes vernalis Engelm. & A. Gray NM 7 N P U Su OROBANCACEAE Orobanche uniflora L. NM 8 N P U Su OXALIDACEAE Oxalis dillenii Jacq. SC/NM 0 N P U SpF Oxalis stricta L. SC/NM 0 N P U Su Oxalis violacea L. SC/NM 5 N P U Sp PHYTOLACCACEAE Phytolacca americana L. SC 0 N P R SuF PLANTAGINACEAE Plantago lanceolata L. SC I P D Sp Plantago major L. NM I P D Su Plantago patagonica Jacq. SC/NM 1 N A D Su Plantago rugelii Dcne. SC/NM 0 N P D Su Plantago virginica Dcne. SC 2 N A D Su POACEAE Agropyron smithii Rydb. SC/NM 3 N P U Su Agrostis hyemalis (Walt.) B.S.P. NM 3 N P D SpSu Agrostis stolonifera L. SC/NM I P W Su Andropogon gerardii Vitman SC/NM 5 N P U SuF Aristida oligantha Michx. SC/NM 1 N A D SuF Bouteloua curtipendula (Michx.) Torr. SC/NM 5 N P U SuF Bouteloua gracilis (H.B.K.) Lag. ex Griffiths SC/NM 4 N P U SuF Bouteloua hirsuta Lag. SC/NM 6 N P U Su Bromus inermis Leyss. SC/NM I P U SpSu Bromus japonicus Thunb. ex Murr. SC/NM I A D SpSu Bromus mollis L. NM I A D Su Bromus tectorum L. SC/NM I A D Sp Buchloe dactyloides (Nutt.) Engelm. SC/NM 2 N P U Su Cenchrus longispinus (Hack.) Fern. SC/NM 0 N P D SuF Chloris verticillata Nutt. SC/NM 0 N P D SuF Cinna arundinaceae L. NM 5 N P R SuF Dactylis glomerata L. SC/NM I P U SuF Dichanthelium acuminatum (Sw.) Gould & Clark SC/NM 6 N P U SpF Dichanthelium leibergii (Vasey) Freckmann NM 7 N P U SpSu Dichanthelium linearifolium (Scribn.) Gould NM 7 N P U SpF Dichanthelium oligosanthes (Schult.) Gould SC/NM 5 N P U SpF Digitaria sanguinalis (L.) Scop. SC/NM I A D SuF Echinochloa crusgalli (L.) Beauv. SC/NM I A W SuF Echinochloa muricata (Beauv.) Fern. NM 0 N A W SuF Eleusine indica L. Gaertn. SC/NM I A D SuF Elymus canadensis L. NM 5 N P U SuF Elymus villosus Muhl. ex Willd. SC/NM 5 N P R SuF Elymus virginicus L. SC/NM 4 N P U Su Eragrostis cilianensis (All.) E. Mosher SC/NM I A D SuF Eragrostis pectinacea (Michx.) Nees NM 0 N A D SuF Eragrostis spectabilis (Pursh) Steud. SC/NM 3 N P D SuF Festuca arundinacea Schreb. SC 0 I P R SuF Festuca obtusa Biehler SC 5 N A D SpSu Festuca octoflora Walt. NM 3 N A D SpSu Glyceria striata (Lam.) Hitchc. SC/NM 5 N P W SuF Hordeum jubatum L. SC/NM 1 N P R SpSu Hordeum pusillum Nutt. SC/NM 0 N A D SpSu Koeleria pyramidata (Lam.) Beauv SC/NM 6 N P U Su Leersia oryzoides L. SC/NM 4 N P W F Leersia virginica Willd. SC/NM 4 N P W F Leptoloma cognatum (Schultes) Chase SC 4 N P U SuF Muhlenbergia cuspidata (Torr.) Rydb. NM 5 N P U SuF Muhlenbergia froadosa (Poir.) Fern. SC 2 N P U SuF Muhlenbergia racemosa (Michx.) B.S.P. SC/NM 4 N P U SuF Muhlenbergia schreberi J.F.Gmel. SC/NM 0 N P R SuF Panicum capillare L. NM 0 N A D F Panicum dichotomiflorum Michx. SC/NM 0 N A W F Panicum virgatum L. SC/NM 4 N P U F Paspalum setaceum Michx. SC/NM 2 N P U SpF Phalaris arundinacea L. SC/NM 0 N P W Su Phleum pratense L. SC/NM I P U Su Poa compressa L. SC/NM I P U SpF Poa palustris L. NM I P R SpF Poa pratensis L. SC/NM I P U SpF Schedonnardus paniculatus (Nutt.) Trel. SC/NM 0 N P D SuF Schizachyrium scoparium (Michx.) Nash SC/NM 4 N P U SuF Sclerochloa dura (L.) Beauv. SC 0 I A D Sp Setaria glauca (L.) Beauv. SC/NM I A D SuF Setaria viridis (L.) Beauv. SC/NM I A D SuF Sorghastrum nutans (L.) Nash SC/NM 5 N P U SuF Sorghum bicolor (L.) Moench SC I P D SuF Sorghum halepesne (L.) Pers. NM I P D SuF Spartina pectinata Link. SC/NM 5 N P W SuF Sphenopholis obtusata (Michx.) Scribn. SC/NM 5 N P U Su Sporobolus asper (Michx.) Kunth SC/NM 3 N P U SuF Sporobolus heterolepis (A. Gray) A. Gray SC/NM 7 N P U SuF Sporobolus vaginiflorus (Torr. ex Gray) Wood SC 1 N A U F Stipa spartea Trin. SC/NM 6 N P U SpSu Tridens flavus (L.) Hitchc. NM 1 N P U SuF POLYGALACEAE Polygala verticillata L. SC/NM 4 N P U SuF POLYGONACEAE Polygonum achoreum Blake NM N A D SuF Polygonum amphibium L. NM 6 N P W SuF Polygonum arenastrum Jord. ex Bor. NM I A D SuF Polygonum aviculare L. SC I A U SuF Polygonum bicorne Raf. SC/NM 0 N A D SuF Polygonum conuolvulus L. SC/NM I A R SuF Polygonum lapathifolium L. NM 2 N A D SuF Polygonum pensylvanicum L. SC/NM 0 N A D SuF Polygonum persicaria L. SC/NM I A D SuF Polygonum punctatum Ell. SC/NM 4 N A W SuF Polygonum ramosissimum Michx. NM 1 N A D SuF Polygonum scandens L. NM 1 N P R SuF Rumex acetosella L. NM I P U SpSu Rumex altissimus Wood SC/NM 0 N P W Su Rumex crispus L. SC/NM I P W SpSu POTAMOGETONACEAE Potamogeton foliosus Raf. SC/NM 5 N P Q Su PRIMULACEAE Androsace occidentalis Pursh SC/NM 1 N A D Sp Lysimachia ciliata L. SC/NM 5 N P W Su RANUNCULACEAE Anemone caroliniana Walt. SC/NM 7 N P U Sp Anemone cylindrica A. Gray SC/NM 5 N P U Su Clematis virginiana L. NM 4 N P R F Delphinium virescens Nutt. SC/NM 6 N P U Su Ranunculus arbortiuus L. SC/NM 1 N A R Sp Ranunculus sceleratus L. SC/NM I A W SuF Thalictrum dasycarpum Fisch. & Ave-Lall. SC/NM 4 N P U Su RHAMNACEAE Ceanothus herbaceus Raf. SC/NM 6 N S U SpSu ROSACEAE Fragaria virginiana Duchn. SC/NM 5 N P U Sp Geum canadense Jacq. SC/NM 3 N P R SpSu Potentilla arguta Pursh. NM 6 N P U Su Potentilla norvegica L. SC/NM 0 N P W Su Potentilla recta L. SC/NM I P U SpSu Potentilla rivalis Nutt. NM 4 N B W Su Prunus americana Marsh. SC/NM 3 N S R Sp Prunus virginiana L. SC/NM 3 N S R Sp Rosa arkansana Porter SC/NM 4 N S U Su Rosa multiflora Thunb. SC/NM I S U Su Rubus allegheniensis Porter NM 4 N P R Sp Rubus occidentalis L. SC/NM 3 N P R SpSu RUBIACEAE Galium aparine L. SC/NM 0 N A R Su Hedyotis nigricans (Lam.) Fosb. SC/NM 7 N P U Su SALICACEAE Populus deltoides Marsh. SC/NM 3 N T R Sp Salix amygdaloides Anderss. SC/NM 4 N T R Sp Salix eriocephala Michx. NM 5 N S W Sp Salix exigua Nutt. SC/NM 3 N S W Sp SANTALACEAE Comandra umbellata (L.) Nutt. SC/NM 6 N P U SpSu SCROPHULAREACEAE Agalinis aspera (Dougl. ex Benth.) Britt. NM 10 N P U SuF Agalinis tenuifloia (Vahl) Raf. SC 5 N A W F Penstemon cobaea Nutt. SC/NM 6 N P U Sp Penstemon grandiflorus Nutt. NM 5 N P U SpSu Verbascum thapsus L. SC/NM I B D Su Veronica agrestis L. SC I A D Sp Veronica arvensis L. SC/NM I A D Sp Veronica peregrina L. NM 0 N A D SpSu SMILACACEAE Smilax hispida Muhl. SC/NM 4 N v R SpSu Smilax herbacea L. var. lasionerua (Small) Rydb. NM 6 N P R SpSu SOLANACEAE Datura stramonium L. SC I A D/R SuF Physalis longifolia Nutt. SC/NM 0 N P U Su Physalis virginiana P. Mill. SC/NM 6 N P U SpF Solanum carolinense L. SC 0 N A D SuF Solanum ptycanthum Dun. ex DC. SC/NM 0 N A U SpF Solanum rostratum Dun. SC/NM 0 N A D SuF TYPHACEAE Typha angustifolia L. SC/NM I P W Su Typha latifolia L. SC/NM 1 N P W Su ULMACEAE Celtis occidentalis L. SC/NM 4 N T R Su Ulmus americana L. SC/NM 3 N T R Sp Ulmus xnotha Wilh. & Ware SC/NM 3 N T R Sp Mmus pumila L. SC/NM I T R Sp Ulmus rubra Muhl. SC/NM 5 N T R Sp URTICACEAE Laportea canadensis (L.) Wedd. SC 4 N P R Su Parietaria pensylvanica Muhl. ex Willd. SC/NM 0 N A R Su Pilea pumila (L.) A. Gray SC 4 N A R SuF Urtica dioica L. SC/NM 1 N P W Su VERBENACEAE Lippia lanceolata Michx. NM 3 N P W Su Verbena bracteata Lag. & Rodr. SC/NM 0 N A D SpF Verbena hastata L. SC/NM 4 N P U SuF Verbena stricta Vent. SC/NM 2 N P R Su Verbena urticifolia L. SC/NM 3 N P U SuF VIOLACEAE Viola pedatifida G. Don SC/NM 6 N P U Sp Viola pedatifida x V. sororia G. Don NM N P U Sp Viola pratincola Greene SC/NM 1 N P U Sp Viola pubescens Ait. NM 5 N P R Sp Viola rafenesquei Greene SC/NM 3 N A R SpF Viola sororia Willd. SC/NM 3 N P U Sp VITACEAE Parthenocissus quinquefolia (L.) Planch. SC 5 N V R Su Parthenocissus vitacea (Knerr) Hitchc. SC/NM 4 N V R Su Vitis riparia Michs. SC/NM 3 N V R Su ZYGOPHYLLACEAE Tribulus terrestris L. SC/NM 0 1 A D SuF Table 1. Species numbers and proportion (%) native and introduced among habitats of Spring Creek and Nine-Mile prairies. Upland % Wetland % Wood % Total % SCP 224 63 62 349 Native 161 * 72 58 92 54 87 273 78 Introduced 63 * 28 05 08 08 13 76 22 NMP 252 77 69 398 Native 199 * 79 73 95 64 92 337 85 Introduced 53 * 21 04 05 05 08 61 15 * significantly different (p<0.05) Table 2. Average richness per plot at Nine-Mile Prairie and Spring Creek Prairie in 1 x 10 m and 10 x 10 m plots in June of 2000. NMP SCP 1 x 10 m 10 x 10 m 1 x 10 m 10 x 10 m Grasslikes 0.22 0.78 1 1.2 Shrubs and Trees 1.22 1.56 0.33 1.56 Cool-season grasses 2.1 2.4 2.9 3.33 Warm-season grasses 1.78 2.56 2 2.44 Forbs 9.4 15 7.4 15.11 Total 14.72 22.3 13.63 23.64 Table 3. Average richness per plot at Nine-Mile Prairie in burned vs. unburned plots. Burned Unburned 1 x 10 m 10 x 10 m 1 x 10 m 10 x 10 m Grasslikes 0.20 0.60 0.00 3.00 Shrubs and Trees 1.40 1.60 1.20 2.00 Cool-season grasses 1.80 2.00 1.75 3.25 Warm-season grasses 2.00 2.60 2.00 2.50 Forbs 7.60 12.20 10.75 17.75 Total 13.00 19.00 15.70 28.50 Table 4. Twenty most abundant forbs in order of abundance for in the fall of 1999 for Spring Creek Prairie (17 plots) compared to Nine-Mile Prairie (9 plots). Values of conservatism are listed under "C". SCP 17 plots C NMP 9 plots C Ambrosia psilostachya 1 Ambrosia psilostachya 1 Trifolium repens * 0 Aster ericoides 4 Vernonia baldwinii 3 Artemisia ludoviciana 4 Aster ericoides 4 Helianthus rigidus 5 Artemisia ludoviciana 4 Amorpha canescens 6 Achillea millefolium 2 Oxalis dillenii 0 Physalis longifolia 0 Asclepias verticillata 2 Cirsium flodmanii 3 Solidago missouriensis 5 Trifolium pratense * 0 Viola pedatifida 6 Conyza canadensis 0 Lespedeza capitata 6 Solidago missouriensis 5 Solidago speciosa 7 Antennaria neglecta 1 Kuhnia eupatorioides 4 Kuhnia eupatorioides 4 Monarda fistulosa 4 Oxalis dillenii 0 Physalis longifolia 0 Euphorbia nutans 0 Rhus glabra 1 Convolvulus arvensis * 0 Callirhoe involucrata 1 Medicago lupulina * 0 Cirsium altissimum 0 Amorpha canescens 6 Solidago rigida 3 Symphoricarpos orbiculatus 2 Solidago canadensis 2 Ruellia humilis 4 Dalea candida 6 Average C value 1.95 Average C value 3.35 * Introduced species Table 5. Twenty most abundant forbs in order of abundance for all of Spring Creek Prairie (48 plots) for the spring and fall of 1999. Values of conservatism are listed under "C". SCP 48 plots Spring '99 C SCP 48 plots Fall '99 C Ambrosia psilostachya 1 Ambrosia psilostachya 1 Oxalis dillenii 0 Trifolium repens * 0 Vernonia baldwinii 3 Vernonia baldwinii 3 Trifolium repens * 0 Aster ericoides 4 Medicago lupulina * 0 Conyza canadensis 0 Linum sulcatum 6 Ambrosia artemesiifolia 0 Aster ericoides 4 Cirsium flodmanii 3 Euphorbia marginata 0 Artemisia ludoviciana 4 Cirsium flodmanii 3 Antennaria neglecta 1 Conyza canadensis 0 Medicago sativa * 0 Melilotus officinalis * 0 Achillea millefolium 2 Artemisia ludoviciana 4 Oxalis dillenii 0 Solidago sp. 4 Medicago lupulina * 0 Viola rafinesquii 3 Physalis longifolia 0 Sisyrinchium campestre 4 Solidago rigida 3 Plantago patagonica 1 Euphorbia marginata 0 Convolvulus arvensis * 0 Solidago missouriensis 5 Achillea millefolium 2 Kuhnia eupatorioides 4 Antennaria neglecta 1 Euphorbia nutans 0 Medicago sativa * 0 Trifolium pratense * 0 Average C value 1.8 Average C value 1.5 * Introduced species Table 6. Abundance of species in each vegetation class for each plot at Nine-Mile Prairie and Spring Creek Prairie. Spring Creek plots begin with the letter 'S'. Nine-Mile plots begin with the letter 'N'. Plot IRF NRF NDF NLF NDW NRW IRW S11 60 41 25 0 0 0 0 S15 23 61 6 0 0 0 0 S21 27 440 3 0 0 0 0 S25 6 59 0 0 0 0 0 S26 1 48 5 0 0 4 0 S27 3 15 6 1 6 3 0 S28 16 188 12 0 0 1 0 S31 36 195 10 0 0 0 0 S35 10 388 64 0 0 15 0 S37 30 254 13 0 1 0 0 S38 35 133 2 0 3 0 0 S43 2 632 0 0 0 3 0 S45 10 92 0 0 0 1 3 S51 8 28 22 0 11 0 0 S55 14 101 50 0 1 7 0 S58 9 125 12 0 0 0 0 S63 0 74 87 0 0 1 0 N71 0 132 217 0 0 1 0 N72 0 86 363 0 14 0 0 N73 0 17 9 0 35 2 0 N74 0 25 189 0 34 0 0 N75 0 59 90 17 73 0 0 N76 0 306 17 0 0 9 0 N77 0 27 179 0 9 0 0 N78 3 43 306 0 21 0 0 N79 0 125 36 0 24 0 0 Table 7. DCA vegetation class scores for forbs and woody species. Values Vegetation Class Axis 1 Axis 2 Axis 3 Introduced ruderal forbs (IRF) -33 223 119 Introduced ruderal woody species (IRW) -109 122 -252 Native ruderal forbs (NRF) 4 0 67 Native ruderal woody species (NRW) 31 -157 144 Native dominant matrix forbs (NDF) 173 80 -21 Native dominant matrix woody species (NDW) 174 37 221 Native late-seral forbs (NLF) 181 46 -525 Table 8. Frequencies (%) of warm-season grasses per 1 [m.sup.2] subplots in 1999. Warm-season grasses SCP NMP Andropogon gerardii 80 97 Aristida oligantha 1 1 Bouteloua curtipendula 52 13 Bouteloua hirsuta 1 0 Eragrostis spectabilis 5 8 Panicum capillare 0 0 Panicum virgatum 0 7 Paspalum setaceum 0 1 Setaria faberi 0 1 Setaria glauca 0 0 Schizachyrium scoparium 67 33 Sorghastrum nutans 46 64 Sporobolus asper 42 14 Sporobolus heterolepis 0 21 Table 9. Frequencies (%) of cool-season grasses per 1 [m.sup.2] subplots in 2000. Cool-season grasses SCP NMP Bromus inermis 89 44 Bromus japonicus 56 0 Dichanthelium oligosanthes 78 78 Dichanthelium acuminatum 11 44 Elymus canadensis 0 22 Poa compresses 33 0 Poa pratensis 67 56 Stipa spartea 0 22 Table 10. C values for each species found in the 17 plots at Spring Creek Prairie in 1999. No value listed means introduced species. Abutilon theophrasti Achillea millefolium 2 Ambrosia artemisiifolia 0 Ambrosia psilostachya 1 Amorpha canescens 6 Andropogon gerardii 5 Antennaria neglecta 1 Aristida oligantha 1 Artemesia ludoviciana 4 Aster ericoides 4 Bouteloua curtipendula 5 Bromus inermis Bromus japonicus Bromus tectorum Cirsium altissimum 0 Cirsium flodmanii 3 Convolvulus arvensis Conyza canadensis 0 Croton texensis 1 Cyperus sp. 3 Dalea candida 6 Desmodium illinoense 7 Dichanthelium acuminatum 6 Dichanthelium oligosanthes 5 Euphorbia marginata 0 Euphorbia nutans 1 Gaura longifora 2 Gaura parviflora 0 Geum canadense 3 Gleditsia triacanthos 1 Grindelia squarrosa 0 Juncus interior 4 Koeleria pyramidata 6 Kuhnia eupatorioides 4 Linum sulcatum 6 Malva neglecta Medicago lupulina Medicago sativa Melilotus officinalis Oxalis dillenii 0 Paspalum setaceum 2 Physalis longifolia 0 Plantago patagonica 1 Poa compressa Poa pratensis Potentilla recta Psoralea esculenta 8 Psoralea tenuifolia 5 Ruellia humilis 4 Salvia azurea 6 Schizachyrium scoparium 4 Setaria glauca Solidago canadensis 2 Solidago missouriense 5 Solidago rigida 3 Sorghastrum nutans 5 Sporobolus asper 3 Strophostyles leiosperma 4 Symphoricarpos orbiculatus 2 Toxicodendron rydbergii 2 Tragopogon dubius Trifolium pratense Trifolium repens Verbena stricta 2 Vernonia baldwinii 3 Viola pedatifida 6 Viola pratincola 1 Average C (native & exotic) 2.29 Average C (native only) 2.98 FQI (native & exotic) 19.02 FQI (native only) 21.69 Table 11. C values for each species found in the 9 plots at Nine-Mile Prairie in 1999. No value listed means introduced species. Achillea millefolium 2 Ambrosia psilostachya 1 Amorpha canescens 6 Andropogon gerardii 5 Aristida oligantha 1 Artemesia ludoviciana 4 Asclepias stenophylla 6 Asclepias syriaca 0 Asclepias verticillata 2 Aster ericoides 4 Bouteloua curtipendula 5 Bromus inermis Bromus japonicus Bromus tectorum Ceanothus herbaceus 6 Cirsium altissimum 0 Convolvulus arvensis Cyperus sp. 3 Dalea purpurea 6 Delphinium virescens 6 Dichanthelium acuminatum 6 Dichanthelium oligosanthes 5 Eragrostis spectabilis 3 Euphorbia nutans 1 Gaura longiflora 2 Helianthus rigida 5 Juncus interior 4 Kuhnia eupatorioides 4 Lespedeza capitata 6 Linum sulcatum 6 Monarda fistulosa 4 Oxalis dillenii 0 Panicum capillare 0 Paspalum setaceum 2 Physalis longifolia 0 Poa pratensis Prunus americana 3 Rhus glabra 1 Rosa arkansana 4 Schizachyrium scoparium 4 Setaria faberi Setera glauca Solidago missouriensis 5 Solidago sp. 3 Solidago speciosa 7 Sorghastrum nutans 5 Sporobolus asper 3 Sporobolus heterolepis 7 Taraxacum officinale Verbena stricta 2 Viola pedatifida 6 Viola pratincola 1 Average C (native & exotic) 2.98 Average C (native only) 3.50 FQI (native & exotic) 21.90 FQI (native only) 23.74 Table 12. Comparison of average C values and FQI for total species lists of Spring Creek Prairie (SCP) and Nine-Mile Prairie (NMP). SCP NMP Upland Total spp. Upland Total spp. Average C (native & exotic) 2.25 2.51 2.78 2.96 Average C (native only) 3.15 3.20 3.48 3.46 FQI (native & exotic) 33.97 47.16 43.97 59.05 FQI (native only) 39.97 52.97 49.21 63.71 Table 13. Comparison of average C values and FQI for 1 x 10 m plots and 10 x 10 m plots at SCP and NMP in 2000. SCP NMP 1 x 10 m 10 x 10 m 1 x 10 m 10 x 10 m Average C (native & exotic) 2.54 2.70 3.21 3.44 Average C (native only) 3.39 3.52 3.51 3.67 FQI (native & exotic) 17.59 20.91 22.01 27.09 FQI (native only) 20.34 23.87 23.02 27.95 Table 14. Simpson's Diversity Index of non-grass species for all of SCP (48 plots), for soil types in common with NMP (17 plots), and for NMP. SCP SCP NMP 48 plots 17 plots 9 plots Index 0.23 0.24 0.17 Reciprocal 4.30 4.18 5.77 Table 15. Examples of grass species in vegetative classes. CIR Cool-season introduced ruderal Bromus inermis Bromus japonicus Poa pratensis CND Cool-season native dominants Dichanthelium oligosanthum Dichanthelium acuminatum WNR Warm-season native ruderal Eragrostis spectabilis Sporobolus asper WND Warm-season native dominants Andropogon gerardii Bouteloua curtipendula Panicum virgatum Schizachyrium scoparium Sorghastrum nutans WNL Warm-season native late-seral species Sporobolus heterolepis Table 16. DCA vegetation class scores for grasses and sedges. Values Vegetation Class Axis 1 Axis 2 Axis 3 Cool-season introduced ruderal grasses (CIR) 18 120 -9 Cool-season native dominant matrix grasses (CND) 57 78 -510 Warm-season native ruderal grasses (WNR) 236 -112 196 Warm-season native dominant grasses (WND) -3 -5 77 Warm-season native late-seral grasses (WNL) -113 450 236 Cool-season native dominant matrix sedges (CNDS) -108 139 267 Figure 5. Species richness for Spring Creek and Nine-mile prairies comparing native and introduced species. Number of species Ninemile Spring Creek Introduced 61 76 Native 337 273 Total Species 398 349 Note: Table made from bar graph. Figure 6. Average richness per plot (1 x 10 m) in 1999 at Spring Creek Prairie in the Spring Fall, and combined averages. Cool-season grasses were counted in the spring, and warm- season grasses were counted in the fall. Spring Fall Total Grasslike 3.38 0.75 2.07 Shrubs and Trees 0.81 1.74 1.28 Cool-season grasses 4.58 4.58 Warm-season grasses 4.99 4.99 Forbs 18.13 13.03 15.58 Total 26.9 20.51 28.49 Note: Table made from bar graph. Figure 7. Average richness per plot (1 x 10 m) in the fall of 1999 among all vegetation types, The data include the nine plots at Nine-mile Prairie and 17 plots in the same soil types at Spring Creek Prairie. SCP 17 plots NMP 9 plots Grasslikes 0.76 0.89 Shrubs and Trees 0.82 1.33 Warm-season grasses 5.12 5.56 Forbs 13.24 9.11 Total 19.94 16.89
Anderson, K. L. 1951. The Effects of Grazing Management and Site Conditions on Flint Hills Bluestem Pastures in Kansas. PhD diss., University of Nebraska-Lincoln.
Connell, J. H. 1978. Diversity in tropical rain forests and coral reefs. Science 1909:1302-1310.
Forman, L. and D. Bridson, eds. 1989. The Herbarium Handbook. Great Britain, Whitstable Litho Printers: 214 pp.
Francis, C. M., M. J. W. Austen, J. M. Bowles, and W. B. Draper. 2000. Assessing floristic quality in southern Ontario woodlands. Natural Areas Journal 20: 66-77.
Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, University Press of Kansas: 1,392 pp.
Hill, M. O., and H. G. Gauch, Jr. 1980. Detrended correspondence analysis: an improved ordination technique. Vegetatio 42: 47-58.
Hitchcock, A. S., and A. Chase. 1950 (reprint 1971). Manual of the Grasses of the United States. New York, Dover Publications
Kaul, R. B., and S. B. Rolfsmeier. 1987. The characteristics and phytogeographic affinities of the flora of Nine-Mile Prairie, a western tall-grass prairie in Nebraska. Transactions of the Nebraska Academy of Sciences 15: 23-35.
Kaiser, J. 1998. Bison prime prairie biodiversity. Science magazine online: http://www, science mag.org/cgi/content/full/280.
Kottas, K. L. 2000. Floristic Composition and Characterization of Spring Creek Prairie, Nebraska. M.Sc. thesis, University of Nebraska-Lincoln.
Magurran, A. E. 1988. Ecological Diversity and Its Measurement. Princeton, Princeton University Press: 179 pp.
McCune, B., and M. J. Mefford. 1995. PC-ORD. Multivariate Analysis of Ecological Data, Version 2.0. Gleneden Beach (Oregon), MjM Software Design
Rolfsmeier, S. B., and G. Steinauer, unpublished. Floristic quality assessment, wetness indices, and heritage ranks for the Nebraska flora.
Simpson, E. H. 1949. Measurement of diversity. Nature 163: 688.
Soil Conservation Service. 1980. Soil Survey of Lancaster County, Nebraska. Washington, D.C., USDA Soil Conservation Service.
Steiger, T.L. 1930. Structure of prairie vegetation. Ecology 11: 170-217.
Swink, F., and G. Wilhelm. 1979. Plants of the Chicago Region, revised and expanded edition, with keys. Lisle, Illinois, The Morton Arboretum: 474 pp.
-- and --. 1994. Plants of the Chicago Region, 4th ed. Indianapolis, Indiana Academy of Science: 921 pp.
Tilman, D., and J. A. Downing. 1987. Biodiversity and stability in grasslands. Letters to Nature 367: 363-365.
Wilhelm, G. S., and L. A. Masters. 1995. Floristic Quality Assessment in the Chicago Region and Application Computer Programs. Lisle, Illinois, Morton Arboretum: 17 pp.
Kay Lynn Kottas
Department of Agronomy and Horticulture
University of Nebraska-Lincoln
Lincoln, Nebraska 68583
Funding for this project was provided by the Center for Great Plains Studies at the University of Nebraska-Lincoln.
|Printer friendly Cite/link Email Feedback|
|Author:||Kottas, Kay Lynn|
|Publication:||Transactions of the Nebraska Academy of Sciences|
|Date:||Jun 1, 2001|
|Previous Article:||Pumpkinseed population characteristics in Nebraska Sandhills lakes (pisces, Centrarchidae: Lepomis gibbosus).|
|Next Article:||Additions to the lichen flora of Nebraska.|