Native Prairie Remnants Research Articles

Adaptation of pathogens to their local plant host, Silphium integrifolium, along a precipitation gradient

AbstractEmpirical evidence of the influence of climate on plant–pathogen coevolution is limited but crucial to understand, as anthropogenic pressures including fragmentation and climate change threaten biodiversity. In this study, we tested patterns of plant–pathogen coevolution using Silphium integrifolium Michx., a native tallgrass prairie species that is undergoing domestication, and its foliar pathogens. We collected seeds from four native prairie remnants from each of three regions along an east–west precipitation gradient in central North America and used these to create three common gardens in each region. In common gardens and remnant prairie populations, we measured symptoms of foliar disease (leaf rust and leaf blotch, both caused by fungal pathogens, and Silphium clear vein (SCV), which we have evidence is associated with a virus). While we did not observe greater disease in the East common garden, we did find that on average the East populations had greater resistance to disease than West populations, consistent with an evolutionary legacy of more rapid coevolution with high precipitation. We also found strong interactions between source region and region of planting for all diseases. The Silphium rust, caused by the specialist pathogen Puccinia silphii, was better able to infect plant populations from the same region. These patterns are consistent with local adaptation of specialist pathogens to their local hosts as expected from Red Queen dynamics. For the generalist fungal pathogen driving leaf blotch, we did not observe evidence of local adaptation. However, we observed a positive correlation in the average level of leaf blotch symptoms observed in individual populations in common gardens with the levels of disease in the S. integrifolium individuals in the prairie remnants of origin, consistent with S. integrifolium genetics determining symptoms in the field. Our results are consistent with pathogen ecology being a major driver of coevolutionary dynamics along productivity gradients. As S. integrifolium is being domesticated for oilseed production, our results identify distinct targets for resistance alleles in breeding efforts and can guide pathogen management strategies.

Invasive Species Change Plant Community Composition of Preserved Prairie Pothole Wetlands

Plant communities in North American prairie pothole wetlands vary depending on hydrology, salinity, and anthropogenic disturbance in and around the wetland. We assessed prairie pothole conditions on United States Fish and Wildlife Service fee-title lands in North Dakota and South Dakota to improve our understanding of current conditions and plant community composition. Species-level data were collected at 200 randomly chosen temporary and seasonal wetland sites located on native prairie remnants (n = 48) and previously cultivated lands that were reseeded into perennial grassland (n = 152). The majority of species surveyed appeared infrequently and were low in relative cover. The four most frequently observed species were introduced invasive species common to the Prairie Pothole Region of North America. Our results suggested relative cover of a few invasive species (i.e., Bromus inermis Leyss., Phalaris arundinacea L., and Typha ×glauca Godr. (pro sp.) [angustifolia or domingensis × latifolia]) affect patterns of plant community composition. Wetlands in native and reseeded grasslands possessed distinct plant community composition related to invasive species' relative cover. Invasive species continue to be prevalent throughout the region and pose a major threat to biological diversity, even in protected native prairie remnants. Despite efforts to convert past agricultural land into biologically diverse, productive ecosystems, invasive species continue to dominate these landscapes and are becoming prominent in prairie potholes located in native areas.

Precipitation, Not Land Use, Primarily Determines the Composition of Both Plant and Phyllosphere Fungal Communities.

Plant communities and fungi inhabiting their phyllospheres change along precipitation gradients and often respond to changes in land use. Many studies have focused on the changes in foliar fungal communities on specific plant species, however, few have addressed the association between whole plant communities and their phyllosphere fungi. We sampled plant communities and associated phyllosphere fungal communities in native prairie remnants and post-agricultural sites across the steep precipitation gradient in the central plains in Kansas, USA. Plant community cover data and MiSeq ITS2 metabarcode data of the phyllosphere fungal communities indicated that both plant and fungal community composition respond strongly to mean annual precipitation (MAP), but less so to land use (native prairie remnants vs. post-agricultural sites). However, plant and fungal diversity were greater in the native remnant prairies than in post-agricultural sites. Overall, both plant and fungal diversity increased with MAP and the communities in the arid and mesic parts of the gradient were distinct. Analyses of the linkages between plant and fungal communities (Mantel and Procrustes tests) identified strong correlations between the composition of the two. However, despite the strong correlations, regression models with plant richness, diversity, or composition (ordination axis scores) and land use as explanatory variables for fungal diversity and evenness did not improve the models compared to those with precipitation and land use (ΔAIC < 2), even though the explanatory power of some plant variables was greater than that of MAP as measured by R2. Indicator taxon analyses suggest that grass species are the primary taxa that differ in the plant communities. Similar analyses of the phyllosphere fungi indicated that many plant pathogens are disproportionately abundant either in the arid or mesic environments. Although decoupling the drivers of fungal communities and their composition - whether abiotic or host-dependent - remains a challenge, our study highlights the distinct community responses to precipitation and the tight tracking of the plant communities by their associated fungal symbionts.

Rates of Historical Anthropogenic Soil Erosion in the Midwestern United States

AbstractErosion degrades soils, reduces crop yields, and diminishes ecosystem services. The total amount of soil that has been eroded since the initiation of farming is unknown in most agricultural landscapes, which hinders assessment of soil erosion trends. In the Midwestern U.S., erosion has caused native prairie remnants to become perched above surrounding farmland, providing an opportunity to measure historical soil erosion rates. We use high‐resolution topographic surveys conducted across erosional escarpments at the boundary between 20 prairies and adjacent agricultural fields and show the median reduction in soil thickness ranges from 0.04 to 0.69 m, corresponding to erosion rates of 0.2–4.3 mm year−1, with a median value of 1.9 mm year−1. We used an association between the measured reduction in soil thickness and topographic curvature to predict regional soil erosion integrated since the beginning of farming to the present. We estimate a median historical erosion rate of 1.8 ± 1.2 mm year−1, which is nearly double the rate considered tolerable by the U.S. Department of Agriculture (USDA). Current soil loss predictions from the USDA National Resources Inventory (NRI) and the Daily Erosion Project (DEP) are lower than our historically averaged erosion rate by a factor of 3 and 8, respectively. We suggest that the NRI and the DEP underpredict soil loss rates because they do not include tillage erosion, a process shown to be important throughout the Midwestern U.S. Our findings indicate that further implementation of conservation practices is needed to reduce the high centennial‐averaged soil erosion rates that we measure to sustainable levels.

Evidence of Adaptation of Little Bluestem to the Local Environment of Central Kansas

Little bluestem is a North American grass species found in native prairie remnants which is used for range, pasture, CRP, and restoration planting. In this study we asked whether the distance between planting site and seed source influenced the growth and survival of little bluestem. In a collaborative project with high school teachers and students, we planted seed at 2 sites in central Kansas, from 7 sources ranging from 6.9 to 814 km distant from the planting sites. We found that our measures of fitness (survival and tiller number) together declined significantly with the distance of the seed source from the site. Our results suggest that local adaptation is important to little bluestem survival and productivity and therefore recommend that land managers seek local sources of seed for range or prairie plantings.

Bacterial communities of soil and earthworm casts of native Palouse Prairie remnants and no-till wheat cropping systems

Earthworms are important ecosystem engineers and modify the physical and chemical properties of soils. However, less is known about how earthworms impact soil microbial communities. We compared bacterial communities of the bulk soil and earthworm casts in native prairie remnants and wheat cropped fields in the Palouse of eastern Washington using next-generation sequencing. Communities among prairie sites were similar, indicating a consistent prairie community. The bulk soil and earthworm casts of native prairie locations had higher richness compared to agricultural sites, but similar diversity. Diversity tended to be higher in bulk soil than earthworm casts in native prairies but not agricultural soils. In native prairies, earthworm casts were enriched in the families Caulobacteraceae, Cellulomonadaceae, Cytophagaceae, and Microbacteriaceae, and the genera Flavobacterium, Caulobacter, Burkholderia, Brevundimonas, compared to the bulk soil. In agricultural soils, Geodermatophilaceae, Flavobacterium and Pseudomonas were relatively more abundant in casts, whereas bulk soil harbored greater relative abundances of taxa related to Acidobacteria GP1. Casts from prairies had higher abundances of Actinobacteria, including Cellulomonas, Pseudonocardia, Geodermatophilaceae, and Propionibacteraceae, whereas casts from agricultural habitats were especially enriched in Flavobacterium and Pseudomonas. Fresh casts from Aporrectodea trapezoides from agricultural sites were highly enriched in Flavobacteriaceae, Pseudomonadaceae, Nocardioidaceae and Geodermatophilaceae and in OTUs related to Flavobacterium, Pseudomonas, and Bradyrhizobiaceae. Co-occurrence networks among communities from bulk soil and earthworm casts collected from agricultural fields were strikingly different than those from prairie soils and formed only two modules of co-occurring taxa, compared to 8–9 modules in the prairie soils, indicating a greater complexity of interactions. Networks from agricultural fields tended to have lower ratios of positive to negative edges (interactions) compared to prairie soils, suggesting more competition and antagonism among bacteria. Thus, the specific co-occurring taxa, as well as the aggregate structure of ecological interactions, are largely distinct between Palouse prairie soil communities versus those of earthworm casts in agricultural settings.

Resource Availability and the Potential for Bison Introduction in a Landscape Mosaic

The tallgrass prairie ecosystem was historically maintained through the interaction of climate, fire, and grazing by large ungulates. Efforts are being made to return large ungulates (bison) back into prairie landscapes, but successful introductions can be constrained by suitable habitat as determined by resource availability (plant biomass, forage quality of the plant biomass, and soil carbon and nitrogen), particularly given some of these tracts are former arable land that has been restored to tallgrass prairie. The objective of this study was to quantify whether plant biomass (available forage) differs between prairie types, if forage quality varies across native prairie remnants and restored prairies, and if these differences are related to carbon and nitrogen storage in soil. We sampled native prairie remnants, low seeded-diversity older restored prairies, and high seeded-diversity younger restored prairies at Nachusa Grasslands, Illinois during July 2014. Total plant biomass differed between the three prairie types, with the high seeded-diversity younger-restored prairies having almost twice that of the low seeded-diversity older-restored prairies and more than twice that of the remnant prairies. In regard to forage quality, the percentage of crude protein in dry matter was greater in the remnant prairies compared to both of the restored prairie types. The high seeded-diversity younger restored prairies had the highest lignin concentration in the forage. The fat content of forage was highest in the high seeded-diversity younger restored prairies. Total soil carbon and nitrogen did not differ between the three prairie types at either the 0–10 cm or 10–20 cm depth. The preliminary findings of this study suggest bison grazing within the introduction unit at Nachusa Grasslands will be more intensive within restored prairies as compared to remnants.

Targeting Introduced Species to Improve Plant Community Composition on USFWS-Managed Prairie Remnants

The quality of plant community composition on US Fish and Wildlife Service (USFWS) lands in North Dakota and South Dakota has declined over the past several decades—the abundance of native species has decreased while the abundance of introduced species has rapidly increased. Extensive efforts have been made to improve plant community composition on USFWS prairies; however, there was not a unified approach to this end in North Dakota and South Dakota until the advent of the Native Prairie Adaptive Management (NPAM) program. The NPAM program provides decision support for the selection of management actions to improve plant community composition of tallgrass and mixed-grass prairies in the Northern Great Plains. We evaluated plant community composition on USFWS native tallgrass and mixed-grass prairie remnants enrolled in the NPAM program in North Dakota and South Dakota to examine effects of management on plant community composition. Our analysis suggests that incorporating certain management actions can improve plant community characteristics on the agency's tallgrass and mixed-grass prairies. We documented increased native species richness and decreased Bromus inermis (smooth brome) relative cover at sites that had been burned two or more times during a four-year period. In contrast, smooth brome relative cover was higher at sites managed by the exclusion of fire and intermittent light grazing or rest. Smooth brome is extremely invasive in native prairie remnants throughout the Northern Great Plains. Thus, our results have marked implications for managers working to reduce the prevalence of smooth brome on public and private lands.

Impact of Restoration and Management on Aggregation and Organic Carbon Accumulation in Urban Grasslands

Core Ideas Few studies have examined SOC accrual in restored urban grasslands. We examined SOC accrual in 14 restored and native grasslands in Chicago. Short‐term (&lt;7 yr) restoration increased microaggregate OC toward levels in native prairies. Longer‐term restoration did not improve total SOC or aggregate OC. Differences in SOC were linked to soil moisture, N, texture, and inputs of C4–C among sites. Understanding the patterns of soil organic carbon (SOC) accumulation in restored grasslands is necessary to determine their potential to sequester atmospheric CO2. Patterns of SOC accrual after grassland restorations are generally based on studies in former agricultural fields, and these studies show an increase in SOC and aggregated‐associated OC over time. In this study, we quantified SOC accrual in a series of restored grasslands situated within the matrix of the Chicago metropolitan region. Soil samples were collected from unmanaged (no restoration), short‐term (&lt;7 yr), and longer‐term restorations (&gt;10 yr) and from native prairie remnants located on Mollisols or Alfisols and analyzed using a combination of physical fractionation (aggregate size) and chemical measurements (organic C [OC], 13C/12C natural abundance). We found that (i) total SOC declined after restoration and remained significantly lower in restored than unmanaged soils, (ii) patterns of aggregate OC in longer‐term restorations were more similar to those in unmanaged than to prairie sites, and (iii) microaggregate OC levels and C4–C inputs into aggregate fractions were significantly higher in short‐ than longer‐term restorations. Thus, an increasing time under management did not enhance SOC accrual. For all sites, path models showed that SOC accrual was correlated with soil N, texture, and moisture, whereas C4–C inputs were significant model terms only in short‐term restorations and prairie sites. Taken together, these results indicate the need to consider inter‐relationships among vegetation and soil factors as influences on SOC accrual rather than simply time under management.

Prairie restorations and bees: The potential ability of seed mixes to foster native bee communities

Restoring native habitat is considered critical to conserving native pollinators threatened by habitat loss and degradation, but little is known about whether ecological restorations, most of which do not target pollinators, can predictably support pollinator communities. In this study we compare plant species richness in common commercial prairie seed mixes to remnant prairies, and we take a modeling approach to examine the ability of these seed mixes to attract bee communities relative to native prairie remnants. Using a large data set from native prairies in Iowa consisting of 70 bee species (≈2700 bee specimens) associated with 54 native prairie plants, we constructed species accumulation curves to model the number of bee species potentially attracted to a restoration with the addition of each plant in a seed mix. Our modeling results indicate commercial prairie mixes will accumulate species at rates similar to prairie remnants, but the bee species richness will be lower than remnants because the plant species richness in samples from prairie remnants is twice that of the average commercial seed mix. However, when commercially available seed mixes were modeled to always include four plant species that were exceptionally attractive to native bee species, most mixes attracted significantly more bees than predicted if random species were added. This further suggests that seed mixes and the resulting restorations do not adequately provide for pollinators and could be significantly improved with the addition of a small number of species. Although the particular optimal species additions to seed mixes will vary regionally, adding species functionally equivalent to those we identify may significantly improve restoration of ecological services provided by native bees.

Ecosystem Carbon Storage and Cycling in Restored and Native Grasslands of the Palouse Region

Conversion of marginal agricultural lands to perennial grassland vegetation has been proposed as a way to enhance terrestrial C sequestration. In the United States, the Conservation Reserve Program (CRP) has facilitated this transition. We studied terrestrial C processes and pools in CRP set‐asides planted with exotic grasses and in native prairie remnants of the Palouse region of northern Idaho and eastern Washington. Aboveground and belowground net primary productivity and litterfall were similar between grassland types. However, prairie remnants had 65% greater root biomass, 21% more soil macroaggregates, and 53% more soil C than CRP sites. For decomposition studies, the plant species Festuca idahoensis and Symphoricarpos albus were used as representatives of the prairie community. Bromus inermis was studied in CRP sites. Decomposition rates of leaf litter were not different among plant species, but S. albus root decomposition (k = 0.28 yr–1) was slower than F. idahoensis (k = 0.56 yr–1) or B. inermis (k = 0.64 yr–1). The C pools and processes measured in this study show that processes that return C to the atmosphere (e.g., root decomposition) are slower in prairie remnants than in the CRP sites. However, high root turnover rates and root biomass in CRP could lead to greater C sequestration in CRP sites than in prairie sites with time.

Patterns of diversity and adaptation in Glomeromycota from three prairie grasslands

Arbuscular mycorrhizal (AM) fungi are widespread root symbionts that often improve the fitness of their plant hosts. We tested whether local adaptation in mycorrhizal symbioses would shape the community structure of these root symbionts in a way that maximizes their symbiotic functioning. We grew a native prairie grass (Andropogon gerardii) with all possible combinations of soils and AM fungal inocula from three different prairies that varied in soil characteristics and disturbance history (two native prairie remnants and one recently restored). We identified the AM fungi colonizing A.gerardii roots using PCR amplification and cloning of the small subunit rRNA gene. We observed 13 operational taxonomic units (OTUs) belonging to six genera in three families. Taxonomic richness was higher in the restored than the native prairies with one member of the Gigaspora dominating the roots of plants grown with inocula from native prairies. Inoculum source and the soil environment influenced the composition of AM fungi that colonized plant roots. Correspondingly, host plants and AM fungi responded significantly to the soil-inoculum combinations such that home fungi often had the highest fitness and provided the greatest benefit to A.gerardii. Similar patterns were observed within the soil-inoculum combinations originating from two native prairies, where five sequence types of a single Gigaspora OTU were virtually the only root colonizers. Our results indicate that indigenous assemblages of AM fungi were adapted to the local soil environment and that this process occurred both at a community scale and at the scale of fungal sequence types within a dominant OTU.

Restoring Tallgrass Prairie and Grassland Bird Populations in Tall Fescue Pastures With Winter Grazing

Restoration of grasslands dominated by tall fescue (Schedonorus phoenix [Scop.] Holub) to native tallgrass prairie usually requires burning, herbicides, or reseeding. We tested seasonal grazing by livestock in winter, combined with cessation of fertilization, as a restoration tool for modifying the competitive dynamics among herbaceous plants to restore tallgrass prairie communities in southeastern Kansas. In 2004–2005, we compared responses of grassland plants and birds across a chronosequence of pastures that were winter-grazed from 1 yr to 5 yr. We compared winter-grazed pastures to pastures grazed year-round and to local native prairie remnants as starting and endpoints for restoration, respectively. Abundance of native warmseason grasses increased from 2% to 3% mean relative frequency in pastures grazed year-round to 18% to 30% in winter-grazed pastures, and increased with duration of winter-grazing. Native warm-season grasses accounted for 1–6% of total live aboveground biomass in pastures grazed year-round, 1–34% in winter-grazed pastures, and 31–34% in native prairie remnants. Tall fescue abundance and biomass were similar among grazing treatments, with a trend for tall fescue to be less dominant in winter-grazed pastures. Tall fescue made up 9–40% of total aboveground biomass in year-round grazed pastures and 10–25% in winter-grazed pastures. Grassland birds showed variable responses to winter-grazing. Dickcissels (Spiza americana) and Henslow’s sparrows (Ammodramus henslowii) were more abundant in winter-grazed pastures, whereas eastern meadowlarks (Sturnella magna) and grasshopper sparrows (A. savannarum) had similar abundance in pastures grazed year-round and during winter. Winter-grazing of pastures dominated by tall fescue combined with suspension of nitrogen fertilization could be an effective restoration technique that allows use of prairie rangeland while improving habitat for sensitive grassland birds.

Covariance between disturbance and soil resources dictates the invasibility of northern fescue prairies

Increasing environmental impacts of exotic organisms have refocused attention on the ability of diverse communities to resist biological invaders. Although resource availability, often related to natural and anthropogenic disturbances, appears central to the invasibility of biological communities, understanding the links between resources, diversity and invasibility is often confounded by the covariance among key variables. To test the hypothesis that community invasibility remains contingent on the type and intensity of disturbance and their impacts on plant community diversity and resource availability, we designed an experiment testing the invasibility of northern fescue prairies by smooth brome (Bromus inermis Leyss.), a Eurasian perennial grass, threatening the structure and function of prairie remnants throughout the Great Plains. Using soil disturbances and herbicide, we imposed treatments manipulating the diversity and resource availability of native prairies. Our observations demonstrate that the vulnerability of native prairies to exotic plant invasions remains contingent on resources. While the establishment of smooth brome seedlings increased with increasing disturbance, its impact depended on the availability of soil nitrogen. As a result, soil burial treatments, simulating disturbance by northern pocket gophers, provided poor recruitment areas for smooth brome, and their low levels of soil moisture and nitrogen, combined with the rapid recovery of the prairie community, compromised seedling establishment. Emphasizing the covariance of diversity and key environmental variables following disturbance, our findings illustrate the importance of disturbance type and intensity on community invasibility. Such a consideration is critical in the conservation and restoration of native prairie remnants throughout the Great Plains.

Dominance of an invasive earthworm in native and non-native grassland ecosystems

More attention is currently being focused on earthworm invasions; however, in many ecosystems the relative abundance of native and invasive earthworm species is unknown. We characterized earthworm populations of two grassland types within the Palouse region: native prairie remnants and Conservation Reserve Program (CRP) set asides planted with exotic grasses. The earthworm community in both grassland types was completely dominated by the exotic-invasive Aporrectodea trapezoides. Only one individual of a native species, Driloleirus americanus (the giant Palouse earthworm), was found in a prairie remnant. No differences were found between prairie remnants and CRP sites for mean earthworm density (24–106 individuals m−2) or fresh weight (12–45 g m−2). Our results suggest that the combined effects of land-use change, habitat fragmentation and competitive interactions have resulted in the decimation of native earthworm populations and dominance of invasive earthworms in native and non-native grasslands of the Palouse region.

Status of the regal fritillary (Speyeria idalia) and effects of fire management on its abundance in northeastern Kansas, USA

The Regal Fritillary (Speyeria idalia), which once occupied prairies and meadows in North America from the upper Great Plains to the Atlantic coast, has disappeared in recent decades from nearly the entirety of the eastern half of its range and has declined westward. In the Great Plains, where the species is limited to native prairie remnants, several large populations are thought to exist, but patterns of occurrence and abundance in the region have not been described in detail. We surveyed prairies within a three county area of northeastern Kansas using distance-sampling along line transects and found Regal Fritillaries present at 70 of 87 sites. Population density varied considerably among sites but was generally much higher at those that had not been burned in the past year. Despite the loss of >99% of its original prairie landcover and the small sizes of remnants $$(\bar x = 7.1\,{\hbox{ha),}}$$ we estimate that our study area supports a globally significant population of ∼12,000 adult individuals. Given the rapidity of decline of Regal Fritillary populations elsewhere, this study establishes important population benchmarks and a practical protocol for future monitoring efforts.

Flowering Phenology and Genetic Similarity among Local and Recently Introduced Populations of Andropogon gerardii in Ohio

Abstract In Ohio and elsewhere, recent grassland plantings in the federal Conservation Reserve Program (CRP) have become much more extensive than native prairie remnants. The seed source for CRP grasslands in Ohio often comes from as far away as Missouri or Texas, which may be undesirable from the standpoint of conservation genetics. The goal of this study was to examine the potential for gene flow from large, recently introduced populations of Big bluestem (Andropogon gerardii, Poaceae) to small local populations of this outcrossing perennial species. We examined the potential for cross‐pollination between three local populations and three introduced CRP populations by comparing flowering phenologies. Flowering times overlapped extensively, indicating that cross‐pollination is possible where local and introduced genotypes co‐occur. To compare genetic variation in local and CRP populations, we analyzed variation at 68 RAPD loci in six populations of each type. Somewhat surprisingly, we found no significant differences in the genetic diversity or composition between the two groups (local vs. CRP). In summary, we found that local and introduced populations of Big bluestem have the potential to interbreed, based on their flowering periods, but further research is needed to determine whether local genotypes harbor unique genetic variation that could be jeopardized by hybridization with introduced genotypes.

Grassland management effects on soil bulk density

Abstract Various grassland management regimes have been and are being utilized in northeastern Kansas, all of which could impact soil properties. Differences in one such property, soil bulk density, could indicate differences in soil quality. Five regimes of privately managed grasslands (cool-season: hay or grazed, warm season: hay, grazed or Conservation Reserve Program (CRP)) in Douglas, Jefferson and Leavenworth counties, Kansas, were sampled for soil bulk density in 2001 and 2002. Cool-season fields have been cultivated historically (late 1800s) and recently (1950s to present) seeded into Bromus inermis, while warm-season fields are either native prairie remnants or CRP. CRP fields have had warm-season native grasses seeded into them after extensive cultivation and soil erosion. Bulk density (dry soil weight/soil volume) cores were taken to a depth of 15 cm (volume = 76 cm3) and dried to constant weight (90°C). CRP had the highest bulk density (0.90 and 0.74 Mg/m3, 2001 and 2002, respectively, p < 0.0...

Floristic and Soil Organic Matter Changes after Five and Thirty‐Five Years of Native Tallgrass Prairie Restoration

We studied two tallgrass prairies and adjacent restoration areas in northeast Kansas to analyze (1) the invasion of native tallgrass prairie species from native prairie source populations into replanted areas; (2) the establishment of planted prairie species five and 35 years after being sown; and (3) the effects of native prairie species on soil organic matter. For the majority of dominant species, composition differed statistically between sampled areas even though seed rain was available from the native tallgrass prairie remnants. Plant community differences were statistically different between each native prairie area and all respective restoration sites according to the Multiple Response Permutation Procedure. In addition, species richness was greatly reduced in replanted areas compared to adjacent native prairie remnants. Soil carbon isotope ratios indicated that the planting of warm‐season grasses resulted in substantial replacement of old soil organic matter by the newly replanted grasses but that it did not create substantial increases of soil organic matter beyond replacement. The lack of accumulation reflects a nutrient‐poor system (nitrogen‐poor in particular), and the relative absence of native or introduced nitrogen‐fixing plant species on the replanted areas may be a significant factor. It appears that restoration of the original highly diverse vegetation component of the tallgrass prairie ecosystem, even when aided by seeding and an adjacent prairie seed source, will occur on carbon‐ and nitrogen‐depleted soils only over very long periods of time (perhaps centuries), if at all.

Distribution of prairies and solonetzic soils in the Peace River district, Alberta

A study of 13 native prairie remnants in the Peace River district of Alberta revealed two community types: a Stipa spartea var. curtiseta – Carex spp. – Artemisia frigida community found on steep, south-facing slopes and a more widespread Carex spp. – Danthonia intermedia – Stipa spartea var. curtiseta community situated on solonetzic-order soils. By using early land survey records and recent soil survey data, a close correlation was found between the large tracts of prairie vegetation and the distribution of solonetzic soils. The solonetzic soils appear to support grasslands and not forests because of their unfavorable ratios of Na to Ca, hard, columnar B-horizon, and relatively impermeable clay pan close to the surface.