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Phylogenetic and functional diversity are relevant for restoration planning, as they influence important ecosystem functions and services. However, it is unknown whether initial phylogenetic and functional diversity of restorations as planned and planted are maintained over time, that is, the extent to which diversity of the restoration planting is reflected in the diversity of the resulting plant community. Furthermore, in the tallgrass prairie, many restorations are planted from seed. Among‐species variation in emergence and establishment affects the transition from seed mixes to realized plant communities in these restorations. We evaluated emergence and early establishment of experimental communities in a biodiversity plot experiment designed to test how phylogenetic and functional diversity influence restoration outcomes. We planted the same experimental communities starting from both seeds and plugs to assess differences in establishment. Our results suggest that phylogenetically and functionally diverse species mixes tend to produce phylogenetically and functionally diverse restored plant communities. After 3 years, experimental communities generally maintained their phylogenetic and functional diversity from seed and plug mixes to established vegetation, despite declines in species richness. While plots planted from seeds had on average 1.3 fewer species than plots planted from plugs, phylogenetic and functional diversity did not significantly differ between the two. Furthermore, most species exhibited no significant differences in percent cover when planted from seeds or plugs. Seeds are generally more cost‐effective for restoration than plugs, and our results indicate these two establishment methods achieved similar biodiversity outcomes. [ABSTRACT FROM AUTHOR]

Views about sourcing plant material for restoration, habitat reconstruction, and revegetation have developed substantially in recent years. In particular, recognition of the prevalence of local adaptation has been incorporated into guidelines that now often recommend local sourcing of germplasm. Demand for these materials frequently outstrips supply, and land management professionals repeatedly report inadequate availability of plant materials at appropriate geographic scale and affordable price. Here, we use focus group interviews to investigate the obstacles impeding production and use of source‐identified native seeds in Minnesota prairie. Focus groups included both producers and users of locally sourced seeds and allowed for open‐ended conversations among professionals within each group. Participants emphasized that unpredictability in demand severely restricts supply. To increase use of locally sourced seeds in restorations, participants identified key priorities: working toward more consistent standards and policies, including revising those of agencies that manage lands; promoting awareness of large ramifications from small changes to relevant laws; increasing communication and education; and increasing the number of seed producers. [ABSTRACT FROM AUTHOR]

Temperate grasslands are experiencing worldwide declines due to habitat conversion. Grassland restoration efforts are employed to compensate for these losses. However, there is a need to better understand the ecological effects of grassland restoration and management practices. We investigated the effects of three different grassland management regimes on plant communities of coastal prairie ecosystems in southwest Louisiana (the United States). We compared old fields, prairie remnants, and restored prairies. Coastal prairies are a unique type of grassland historically present across southeast Texas and southwest Louisiana. Old fields represent former coastal prairie habitats allowed to revegetate naturally without active management. Remnant coastal prairies are small, isolated patches of comparatively intact prairie. Restored coastal prairies have been actively restored by planting native coastal prairie vegetation and managed with prescribed burning, mowing, and/or removal of invasive non‐native species. Our work was conducted in three old fields, four remnants, and four restored prairies. Old fields were dominated by non‐native species with low conservation value, whereas remnant prairies were dominated by native species with high conservation value. Remnants had a mean species richness of 75 species per site, which is higher than most other tallgrass prairie ecosystems in North America. Restored sites were dominated by native species with high conservation value, although the composition differed between restored and remnant sites. Collectively, our results: (1) reinforce the importance of identifying and preserving remnant coastal prairies; and (2) show that restoration of degraded coastal prairies is a viable strategy for supporting the persistence of these unique grassland ecosystems. [ABSTRACT FROM AUTHOR]

The decline in migratory monarch butterflies (Danaus plexippus) over the past 20 years has been attributed to several drivers, including loss of their host plants (milkweeds Asclepias spp.). This has sparked widespread interest in milkweed ecology and restoration. We developed a model on environmental and habitat‐type variables to predict milkweed abundance by sampling 93 prairie plantings (47 conservation plantings and 46 roadsides) and 5 unplowed prairie remnants throughout the state of Iowa, United States. Milkweeds were censused in 10–25 random locations within each site, and data on plant diversity, age of planting, soil characteristics, and management were tested as predictors of abundance. Milkweed densities of all species combined were highest in remnant prairies (8,705 stems/ha), intermediate in roadside plantings (1,274 stems/ha), and lowest in conservation plantings (212 stems/ha). Most milkweeds were common milkweeds Asclepias syriaca, which were more abundant in roadside than conservation plantings. Remnants contained the most milkweed species. Total milkweed and common milkweed abundance were both predicted by higher soil pH, a more linear site shape, and lower soil bulk density across restorations. Our results indicate that common milkweed is maintained by disturbance, and establishes readily in rural roadside habitat. Remnants are important as reservoirs for multiple milkweed species and should be protected. [ABSTRACT FROM AUTHOR]

The decline of wild bee pollinators has prompted habitat reconstruction in many regions around the world in order to increase the floral resources available to pollinators. Relatively little research has monitored the genetic differentiation and the relatedness of founding bumblebee populations during the colony recruitment process after vegetation is planted in the landscape. We surveyed nine 3‐year post‐planting reconstructed prairie sites located in the corn belt of the U.S. Midwest, where the landscape is largely dominated by industrialized row crops. Using seven microsatellite loci from 103 Bombus griseocollis, we examined the population genetics of this generalist bee's colonies established on these newly constructed prairie sites. When analyzed, B. griseocollis populations from an older reconstructed site were more genetically distinct from newly established bumblebee populations on reconstructed sites, while the new reconstructed sites exhibited no genetic structure. The floral richness or abundance at the reconstructed sites did not contribute to the allelic richness of the recolonized bumblebee populations. We did, however, find significant negative correlations between the bumblebee populations' allelic richness and the percent coverage of row‐crop farmland in the surrounding landscape and positive correlations between the allelic richness and forest and woody wetland habitat covers. This finding strongly indicates the importance of the composition of the surrounding landscape in the recruitment period of the founding pollinator populations. [ABSTRACT FROM AUTHOR]

Invasive species are a common problem in restoration projects. Manipulating soil fertility and species arrival order has the potential to lower their abundance and achieve higher abundances of seeded native species. In a 7‐year experiment in Missouri, United States, we tested how nutrient addition and the timing of arrival of the invasive legume Lespedeza cuneata and seeded native prairie grass and forb species influenced overall community composition. Treatments that involved early arrival of seeded forb and grass species and late arrival of L. cuneata were most successful at creating community structure that fulfilled our restoration goals, displaying high abundance of seeded native forb species, low abundances of L. cuneata, and non‐native species. There were few treatment interactions, with the exception that timing seeded native forbs and timing of L. cuneata arrival interactively influenced the abundance of seeded native forbs. This suggests that the individual treatments are supporting the restoration goals, such as creating a community with low abundance of L. cuneate or high abundance of native seeded species, without restricting each other. This study demonstrates the importance of priority effects in disturbed habitats prone to invasion, the lasting effects of initial seeding on long‐term community composition, and the potential for fertilization to positively benefit restoration of degraded grasslands. [ABSTRACT FROM AUTHOR]

Forbs comprise most of the plant diversity in North American tallgrass prairie and provide vital ecosystem services, but their abundance in prairie restorations is highly variable. Restoration practitioners typically sow C4 grasses in high abundances because they are inexpensive, provide fuel for prescribed fires, can dominate reference sites, and suppress weeds that suppress sown forbs. However, C4 grasses can also suppress sown forbs, calling this practice into question. We evaluated how C4 grasses influence the abundance and diversity of sown forbs in 78 restored prairies across Illinois, Indiana, and Michigan. We found that the direct negative effects of C4 grasses on sown forbs outweighed indirect positive effects that occurred as C4 grasses suppressed nonsown species, which in turn suppressed sown forbs. This pattern was especially strong for the C4 grass big bluestem (Andropogon gerardii). Therefore, strategies to promote big bluestem and other C4 grasses would not promote sown forbs. Although C4 grass cover was not strongly related to two hypothesized drivers (time since fire or site age), seeding density of C4 grasses increased their cover. Sown forb cover also increased with forb seeding density, increased indirectly with fire (through its negative effect on nonsown species), and decreased indirectly with soil water‐holding capacity (through its positive effect on nonsown species). These results highlight the complex interplay of species groups during grassland restoration and show how managers can promote sown forbs in restored prairies: increasing forb seeding density and reducing time since fire and the abundance of C4 grasses and weeds. [ABSTRACT FROM AUTHOR]

Restoration outcomes are variable, which impairs our ability to plan projects, meet goals, and predict restoration outcomes. Understanding the drivers of this variation is an important research need, especially within urban ecosystems, which support altered abiotic and biotic conditions and face higher rates of loss and degradation than non‐urban areas. Despite the importance of urban areas for restoration, research and practice have largely focused on non‐urban areas. It is unclear if we can extend current knowledge from restoration ecology to urban systems. Here, we surveyed 30 urban prairie restoration plantings across southern Michigan. We collected plant community and site condition data (e.g. soil attributes) and we quantified landscape context as the percentage of urban land surrounding each site. Variation in plant community composition among restorations was related primarily to site‐level factors, such as soil compaction, texture, and water‐holding capacity, rather than landscape context. Non‐prairie species were structured primarily by the local site conditions. There was an increase in non‐prairie richness for sites that experienced warmer local climate conditions, while there was a decrease in non‐prairie richness for sites where soils were less compacted, sandier, and had elevated water‐holding capacity. Prairie species richness responded oppositely. Overall, our study revealed specific factors structuring restoration outcomes in urban contexts and illustrated the importance of local site conditions, not surrounding landscape context, for shaping plant community composition. Restoration practices developed in non‐urban areas should be extended to urban contexts to better understand the impact of local site conditions on plant community development. [ABSTRACT FROM AUTHOR]

Reestablishment of native plant communities is often the primary focus of ecological restoration. This is especially true for prairie restoration, which often struggles to establish diverse forb communities. An often‐overlooked component in plant reestablishment is pollinators, with 85% of forbs requiring pollination for seed reproduction. A deeper understanding of the relationship between plant and pollinator communities could improve prairie restoration success. Our goal was to determine if prairie restoration is successfully reestablishing forb and pollinator communities and their interactions by measuring plant–pollinator networks. We hypothesized that both forb and pollinator communities would be less diverse and abundant in restoration sites compared to intact prairie remnants, and that as a result, plant–pollinator networks in restoration sites would have higher nestedness and connectance, but lower modularity and network specialization than remnant sites. To test this, we measured plant–pollinator networks and forb communities from June to September 2020 at three restored and three remnant Palouse Prairie sites in eastern Washington, United States. We found that although restored sites had lower species richness of forbs and pollinators and different community composition, forb and pollinator abundance was comparable between treatments. Forb abundance in restored sites was equivalent to prairie remnants due to the presence of invasive forbs. However, these differences in community composition and diversity did not appear to impact network metrics including nestedness, connectance, modularity, and network specialization, which were similar between remnant and restored sites. Our results suggest that the structural characteristics of plant–pollinator networks can be maintained by different plant communities. [ABSTRACT FROM AUTHOR]

Restoration of grassland ecosystems is essential for mitigating global losses of biodiversity and is typically initiated to foster persistent, long‐term increases in biodiversity. Yet, evaluating long‐term impacts of restoration on biodiversity is rare, especially across sites restored using consistent methods. Evaluation of restoration outcomes is particularly important for increasing predictive capacity in restoration ecology to determine the level of restoration effort that is required to achieve both short‐ and long‐term restoration goals. We conducted a multisite study that explicitly compared the impacts of no intervention ("passive" or "natural" recovery), low intervention (seeding native plants), and moderate intervention (seeding native plants and using fire management) at 32 restored prairies differing in the age of restoration (3–23 years). Grasslands with natural recovery have equivalent native plant species richness compared to sites with low and moderate restoration intervention, however, they have significantly lower‐quality vegetation, as measured by Floristic Quality (mean C). We found that managing restored prairies with fire maintains native plant richness over time and is correlated with higher vegetation quality and presence of seeded species. Seed mixes with a high mean C score are positively correlated with plant community quality. However, seed mixes with more species are negatively correlated with the proportion of seeded species present. We found that while the degree of restoration intervention has no effect on the number of native plant species, greater levels of assisted recovery are required to produce restored prairies that resemble high‐quality remnant vegetation and, especially, to maintain these successes over the long term. [ABSTRACT FROM AUTHOR]

Seed supply often limits the size and scope of restoration projects that require active revegetation. To meet demand from more and larger tallgrass prairie restoration projects in the Great Plains, U.S.A., seed is wild-harvested-collected from remnant habitats-using agricultural combine harvesters. We investigated the potential impacts of wild-harvest by comparing prairie remnants of northwestern Minnesota that varied in their histories of harvest frequency but were otherwise similar. We asked: (1) Do wild-harvested prairies differ in species composition from unharvested prairies? (2) If so, can life history traits be used to predict the response of prairie communities to wild-harvest? We conducted a retrospective study of 17 prairies harvested for seed frequently (annually/biennially), infrequently (2-3 times), or not at all. We sampled vegetation at 45 points within each site, recording all species present within 0.25 m2 quadrats. To address the first question, we used non-metric multidimensional scaling and Mantel tests, followed by analysis of variance contrasts to identify any species less likely to occur on frequently harvested sites ('harvest-negative'). For the second question, we used logistic regression to test whether lifespan, clonality, and seed production predicted harvest-negative species. Plant community composition in frequently harvested prairies differed from that of infrequently or unharvested prairies. Fourteen species, generally short-lived and non-clonal, were classified as harvest-negative. Our results suggest that frequent wild-harvest disrupts reproduction of species relying on seed, and that life history traits may provide a basis for predicting a species' response to wild-harvest. [ABSTRACT FROM AUTHOR]

In ecological restoration, seed sourcing is often among the first and most critical steps in achieving restored populations that establish and reproduce successfully, while also having the genetic capacity to adapt to future change. Many approaches have been proposed to guide seed sourcing for restoration, including a strong focus on local seed sources, the use of assisted gene flow or assisted migration, and regional admixture provenancing. The goal of this research was to evaluate these issues in the context of grassland restoration. We collected seed of Chamaecrista fasciculata, an annual native to the prairies of North America, from four locations along a latitudinal gradient. We generated inter‐ and intrapopulation crosses and grew them in two common gardens located in restored prairies in southeast Minnesota. We found that northern populations tended to flower and fruit earlier than southern populations, while hybrids generally had intermediate phenologies. There were strong fitness benefits of hybridization, particularly among the local crosses. However, the plants grown from our southernmost seed source produced few mature seed pods in the common gardens before the advent of fall frost, suggesting that translocating populations across significant latitudinal distances may be problematic. Taken together, our findings support a regional admixture provenancing approach while indicating that assisted migration and assisted gene flow across latitudinal distances of three degrees or more compromises fitness in this species. [ABSTRACT FROM AUTHOR]

Understanding patterns of seed predation in tallgrass prairie restorations is vital because seed additions are often used by managers to increase diversity and promote native species. However, the success of seed additions depends on the extent of seed predation. It is not clear how seed predation varies through time and to what extent it is affected by various commonly used management techniques in grasslands (e.g. spring or fall prescribed burns, mowing). We examined how predation of Sorghastrum nutans seeds changed during eight trials between June 2018 and April 2019 in plots that received one of four different plant litter removal treatments (fall mow, fall burn, spring burn, and unaltered control). Granivory varied throughout the year, reaching its peak in the late fall and early winter. However, we found that seed predators consumed significantly fewer seeds when litter was removed following fall burn and fall mow treatment applications. These treatments occurred during times when granivory was otherwise high in areas where litter remained intact (control and spring burn plots). Our findings highlight the importance of management decisions and how they interact with granivory in grassland restorations. Both time of year and litter cover determine seed predation rates; seed predators consume more seeds when seeds are abundant but rely on intact litter cover while foraging. This suggests that if seeds are added during the fall, litter should be removed to minimize the loss of seeds to granivory. Alternatively, seed additions during the spring are likely to experience lower rates of seed predation. [ABSTRACT FROM AUTHOR]

Recovering biodiversity is a common goal of restoration, yet outcomes for animal communities are highly variable. A major reason for this variability may be that active restoration efforts typically target plant communities, with the assumption that animal communities will passively recover in turn. However, this assumption remains largely unvalidated experimentally making it unclear how plant‐focused restoration strategies influence animal communities. We evaluated how the diversity of seed mixes used to restore tallgrass prairies (a common plant‐focused technique) influenced the recovery of ant community diversity and composition. Our study took place within a large‐scale restoration experiment in southwest Michigan, where 12 former agricultural fields are being restored to tallgrass prairie by sowing seeds of prairie plant species native to our region. Half of each field was seeded with 12 prairie species and the other half with 72 prairie species. Sites restored with high diversity seed mixes increased plant species richness, but did not consistently influence ant richness or community composition. Instead, ant species richness and composition were related to an interaction between realized plant species richness (which was only partly structured by seeding treatments) and environmental structure. Specifically, ant richness increased more with higher realized plant richness when vegetation cover was lower and soil‐surface temperatures were higher. Our findings illustrate how plant and animal communities can respond differently to plant‐focused restoration efforts. Despite this, plant community restoration can structure animal community responses, in concert with environmental factors. Layering additional restoration strategies onto existing plant‐focused approaches may further benefit biodiversity across taxa. [ABSTRACT FROM AUTHOR]

One of the challenges in ecological restorations is that some native plant species are difficult to reestablish in disturbed or invaded landscapes. Some invasive plant species negatively impact soil biota, such as arbuscular mycorrhizal (AM) fungi, which can lead to feedbacks that facilitate their dominance in a landscape. The winter annual grass, Ventenata dubia, is rapidly invading North American grasslands, however, the effect of its invasion on AM fungi, plant communities, and soil properties is not well known. In a greenhouse and field experiment, we tested (1) whether the abundance of viable AM fungal propagules is altered in soil invaded by V. dubia; (2) how plant community composition, species richness, and/or diversity may be impacted by V. dubia; and (3) whether soil properties, such as pH and organic matter (OM) vary across invasion levels. We found that the effect of V. dubia on the abundance of mycorrhizal propagules varied among sites and did not reduce the species richness or diversity of resident plant communities. Higher canopy cover of V. dubia was associated with higher soil pH and OM, which suggests either V. dubia invasions change these soil properties, or that V. dubia preferentially invades these areas. Our findings suggest V. dubia does not consistently alter above‐ or belowground communities; however, the potential link between V. dubia invasions and soil pH and OM deserves additional investigation. A better understanding of how invasive annual grasses impact plant and soil communities will be useful in informing restoration efforts in landscapes impacted by invasive species. [ABSTRACT FROM AUTHOR]

We investigated the plant species diversity, community assemblage, net primary production and soil carbon sequestration in an old field (OF), which went through passive restoration with spontaneous secondary succession, and a restored prairie (RP), which went through active restoration with reintroduction of native plants. The passive restoration in OF did not attain as high diversity and richness of plant species as did in RP. Our NMS (nonmetric multidimensional scaling) ordination revealed a clear divergence of RP and OF vegetation with dissimilar species compositions to separate paths of succession trajectory. The spontaneous succession in OF has made very little progress due to a potentially strong inhibitory priority effect of invasive plants. The belowground biomass in the high‐diversity RP was 1.3× higher than the low‐diversity OF. We found no measurable difference in soil C sequestration between RP and OF at this time, possibly due to edaphic factors, lack of legumes, or both. Human intervention is needed for restoring abandoned croplands—highly disturbed, fragmented and isolated habitats—to tallgrass prairies in the U.S. Midwest. Our recommended intervention includes but is not limited to removal of exotic plants, further augmentation of native plants (particularly legumes), and periodic burns. [ABSTRACT FROM AUTHOR]

Insect herbivory of ovules and seeds is known to have a negative impact on individual plant reproductive success by reducing overall seed set. Although this seed set reduction has been well documented in plant populations found in native habitats, little work has been done on populations found in restored habitats. In a 4-year study (2001–2004), I investigated the herbivory of the Gelechiid moth ( Coleotechnites eryngiella) of Eryngium yuccifolium populations in native and restored prairies. Data were collected from 20 E. yuccifolium populations (10 native prairies/10 restored prairies) in Illinois. Percent herbivory and percent seed set were determined for each population. From 2001 to 2004, percent herbivory in prairie restorations ranged from 0 to 93 and percent seed set ranged from 2 to 82. In native prairies, percent herbivory ranged from 0 to 98 and percent seed set ranged from 0 to 71. No differences were found between native and restored prairies for percent herbivory or percent seed set. However, significant differences were found among years for percent seed set. This study shows that the antagonistic effects of insect herbivory can reach similar levels in restored and native prairies. [ABSTRACT FROM AUTHOR]

To restore diversity of native vegetation, we must understand factors responsible for diversity in targeted communities. These factors operate at different spatial scales and may affect the number and relative abundances of species differently. We measured diversity of plant species and functional groups of species in replicated plots within paired restored and remnant (relic) tallgrass prairies at three locations in central Texas, U.S.A. To determine the contributions of species abundances and of spatial patterns of diversity to differences between prairie types, we separated diversity into richness and evenness (relative biomass) and into within-plot ( α), among-plot ( β), and prairie ( γ) components. Species diversity was greater in remnant than in restored prairies at all spatial scales. At the γ scale, both species richness and species evenness were greater in remnants because of greater spatial variation in species composition. At the α scale, remnants were more diverse because of greater richness alone. Mean α richness correlated positively with the size of the species pool in restored prairies only, implying that in remnants, α richness was influenced more by colonization dynamics than by the number of species available for colonization. Plots in remnant prairies contained more functional groups and fewer species per group than did plots in restored prairies, suggesting that resource partitioning was greater in relic prairies. Our results are consistent with the interpretation that local ecological processes, like resource partitioning and limitations on seed dispersal, contribute to the greater diversity of remnant than restored prairies in central Texas. Restoration practices that limit abundances of competitive dominants, increase the number of species in seed mixtures, and increase the proximity of plants of different functional groups thus may be required to better simulate the plant diversity of tallgrass prairies. [ABSTRACT FROM AUTHOR]

Prescribed burning is an important tool for managing and restoring prairies and other ecosystems. One effect of fire is plant litter removal, which can influence seedling establishment. Four experimental treatments (burned, clipped and raked to remove litter, burned with litter reapplied, and unmanipulated) were applied to 2 × 2.5–m plots in three western Oregon, United States, upland prairies to determine how burning affects seedling establishment. Seeds of common exotic and native prairie species were sowed into the experimental plots after treatments. Seedlings were censused the following spring. The experiment was repeated on each of the three sites, representing three common types of prairie vegetation: an Annual Exotic Grass site, a Perennial Exotic Grass site, and a Native Bunchgrass site. In both the Annual Exotic Grass and the Perennial Exotic Grass sites, burning significantly improved native, but not exotic, seedling establishment over those on unburned plots. Litter removal was a significant component of this burn effect, particularly on the Perennial Exotic Grass site. In these winter-moist systems, the net effect of litter is to inhibit seedling establishment. Burning treatments on the Native Bunchgrass site significantly increased seedling establishment only of short-lived exotic species. These results suggest that in prairie ecosystems similar to the Annual and Perennial Exotic Grass sites, prescribed burning followed by sowing native seeds can be an effective restoration technique. Burning alone or sowing alone would be counter-productive, in the first case because increased establishment would come from exotic species and in the second case because establishment rates are low in unburned plots. [ABSTRACT FROM AUTHOR]

Recent losses and fragmentation of tallgrass prairie habitat to agriculture and urban development have led to corresponding declines in diversity and abundance of plants and birds associated with such habitat. Mowing and burning are alternative management strategies for restoring and rejuvenating prairies in fragmented landscapes, but their specific, comparative effects are the subjects of ongoing evaluation. We compared the responses of plant and bird communities on four sets of mowed, burned, and untreated sites of small (3-10 ha), fragmented tallgrass prairies at the DeSoto National Wildlife Refuge (DNWR), Iowa, U.S.A., during May-July in 1998 and 1999. Species richness and diversity of plants, resident grassland birds, and communities of birds associated with grassland edges (edge species) were independent of treatment. Although not affecting species richness and diversity in plant communities, mowed sites ranked lower in total plant coverage and total forb coverage than burned sites or untreated sites. In contrast, untreated sites had more coverage by shrubs, suggesting that mowing and burning did retard shrub encroachment. Overall, abundance and diversity of plants and birds were generally insensitive to management strategies. Small, fragmented sites of rare habitat may not respond in the short term to management treatments and may not be capable of supporting highly diverse communities, no matter how intensively manipulated. It is more probable that diversity of native prairie communities can be enhanced and restored only through long-term efforts, acquisition of large land units capable of supporting stable populations, and deliberate reintroduction of species of high conservation value. [ABSTRACT FROM AUTHOR]

Structural attributes of the C4, perennial bunchgrass Schizachyrium scoparium in restored prairies may be affected by the time since restoration. One hundred plants each in 8-, 17-, and 23-year-old restored prairies and a native Texas Blackland prairie were assessed for the presence/absence and diameter of a hollow crown (i.e., dead center portion), degree of fragmentation, plant height, and tiller density. Structural attributes of S. scoparium plants were generally (1) different between recent (8 years) and older (17 and 23 years) restored prairies (2) similar between the 17- and 23-year-old restored prairies, and (3) more similar between the 8- and 17-year restored prairies and the native, remnant prairie than between the 23-year restored prairie and the native prairie. Plants were shorter in restored prairies, regardless of time since restoration, than in the native prairie. Mean basal area of plants was 80–163% greater in the 17- and 23-year restored prairies compared with the native and 8-year restored prairies. Percentage of hollow crowns and fragmentation was smallest in the 8-year restored prairie, largest in the 17- and 23-year restored prairies, and intermediate in the native prairie. Tiller density exhibited inverse second-order polynomial decreases with increasing plant basal area for all prairies. In contrast to tiller density, diameter of hollow crowns increased logarithmically with increasing plant basal area. Structural attributes of S. scoparium in restored prairies changed predictably with age, despite growing in different communities. [ABSTRACT FROM AUTHOR]

Litter-removing disturbances such as fire in grasslands temporarily increase available resources for plants, opening a window of opportunity for new establishment as communities recover. At this time, new individuals or species could be added to the community as a result of germination from the local seed bank. In reconstructed grasslands this may be problematic, as the seed bank may contain a suite of undesired species reflective of prior and surrounding land uses. In two, 25-year-old, low-diversity reconstructed grasslands, we tested the effect of local seed bank establishment following litter-removing disturbance using seedling removal plots (1 m2) and plots where natural seedling establishment was allowed. Following disturbance, the vegetation was either left intact or hayed to enhance seedling establishment (a common practice following inter-seeding efforts). Although the seed bank and seedling community were dominated by resident grasses ( Andropogon gerardii and Poa pratensis), recruitment from the seed bank increased species richness and reduced evenness through the addition of forb species (including Cirsium arvense) in one of the study sites. Haying temporarily altered the abundances of the dominant grasses, but did not consistently affect seedling recruitment. Disturbances that facilitate seed bank recruitment may promote establishment of undesired species within reconstructed grassland communities, and we need to take steps to better manage the contributions into and recruitment from the seed bank to reconstruct sustainable grasslands. [ABSTRACT FROM AUTHOR]

Restored grasslands comprise an ever-increasing proportion of grasslands in North America and elsewhere. However, floristic studies of restored grasslands indicate that our ability to restore plant communities is limited. Our goal was to assess the effectiveness of restoration seeding for recovery of key plant community components on former exotic, cool-season pastures using a chronosequence of six restoration sites and three nearby remnant tallgrass prairie sites in West-Central Iowa. We assessed trends in Simpson's diversity and evenness, richness and abundance of selected native and exotic plant guilds, and mean coefficient of conservatism (mean C). Simpson's diversity and evenness and perennial invasive species abundance all declined with restoration site age. As a group, restoration sites had greater richness of native C3 species with late phenology, but lower richness and abundance of species with early phenology relative to remnant sites. Total native richness, total native abundance (cover), mean C, and abundance of late phenology C3 plants were similar between restoration and remnant sites. Observed declines in diversity and evenness with restoration age reflect increases in C4 grass abundance rather than absolute decreases in the abundance of perennial C3 species. In contrast to other studies, restoration seeding appears to have led to successful establishment of tallgrass prairie species that were likely to be included in seeding mixtures. While several floristic measures indicate convergence of restoration and remnant sites, biodiversity may be further enhanced by including early phenology species in seeding mixes in proportion to their abundance on remnant prairies. [ABSTRACT FROM AUTHOR]

We studied the effects of vegetation species richness, diversity, and structure on grassland arthropod communities of 23 sites in northeastern South Dakota and southeastern North Dakota. Sites were selected to represent a vegetation species diversity gradient, and three vegetation cover types, including native unseeded grassland, low‐diversity seeding known as dense nesting cover (DNC) for waterfowl, and high‐diversity seed mix. During July of 2016, pan traps and sweep nets were used to survey the grassland arthropod community. A total of 25,521 arthropods representing 107 taxonomic families were collected. Richness, diversity, and biomass of arthropods did not differ among cover types. Vegetation richness and diversity, cover type, percent live vegetation and native cover, and litter depth were important predictors of arthropod community measures, and multivariate analysis of the arthropod community indicated significant differences between native and DNC study sites; explained by differences in vegetation richness, percent forb cover, and litter depth. Results of our study suggest that species richness of grassland restoration seeding mixes likely impacts arthropod richness and diversity, and DNC does not produce arthropod communities similar to native prairie. Additionally, because vegetation structural variables were important determinants of arthropod community measures, grassland management practices will influence the resulting arthropod community and influence the success of grassland restoration using high‐diversity seed mixes. Results of our study promote the potential for successful restoration outcomes using high‐diversity seed mixes, and indicate that low‐diversity, non‐native seed mixes, such as DNC, do not fully restore native grassland arthropod communities. [ABSTRACT FROM AUTHOR]

Plains rough fescue (Festuca hallii), once a dominant grassland in the Northern Great Plains, has been reduced to a fraction of its original extent by agricultural intensification and energy sector disturbances and has become a threatened community type. Despite thousands of kilometers of pipelines in grasslands, little is documented about long‐term restoration outcomes. This research assessed recovery of rough fescue grassland 6–21 years after pipeline construction with topsoil stripping and natural regeneration relative to undisturbed reference sites in south‐central Canada. Soil properties varied between pipelines and undisturbed prairie, although most were within theoretical values to support plant growth and development. Vegetation cover, species richness and Shannon diversity and evenness did not differ significantly between pipelines and undisturbed prairie. Multivariate analysis (multi‐response permutation procedure) showed plant community composition, and its dominant species differed significantly between pipelines and undisturbed prairie. Bray–Curtis dissimilarity indices showed dominant species and functional species groups on pipelines were more similar to undisturbed prairie than the undesirable species group. Presence of early‐ to late‐successional species and increasing F. hallii with pipeline age indicate restoration was possible with topsoil salvage and replacement, using natural regeneration as a revegetation method, but requires time to develop and restore a typical rough fescue grassland ecosystem. [ABSTRACT FROM AUTHOR]

Prairie restorations typically differ from remnant prairies in forb composition; long‐lived, late‐successional plants are often missing. To study establishment of such species, we set up a field experiment where seeds of the threatened, long‐lived Asclepias meadii were sown individually into the field with initial fire and soil disturbance treatments. We returned each year for 11 years to record the presence/absence, size, and reproduction of each plant. Individual plants were sometimes observed 1 year, not observed a subsequent year, and then observed again. We therefore analyzed survival data with mark‐recapture models and found that the probability of a seed germinating and the resulting plant surviving for 11 years was 0.057 (5.7%). Probability of detection was approximately 0.80, suggesting that we did not observe all living plants. Vegetative dormancy, herbivory on above‐ground parts, and observer error could all be responsible. We found no relationship between plant survival and the initial burn/disturbance treatment or previous year precipitation. Plants that were observed in the last study year were individuals that had, on average, greater size in earlier years. Three plants produced flowers and two produced fruit; we believe such reproductive success has not been previously documented for seed of A. meadii sowed into a restoration site. Our restoration study dovetails with the more typical plant community restoration research. In such studies, seeds of many species are sown, but often the late successional species do not establish. We show the value of detailed multiyear monitoring to determine the fate of such plant introductions. [ABSTRACT FROM AUTHOR]

A single fall-season prescribed burn and two consecutive fall-season prescribed burns were conducted in 1988 and 1989 to quantify the effects of fire intensity and frequency on woody species in two Willamette Valley wet prairies. Fuel biomass, fuel properties, fire behavior, biomass consumption, and changes in woody species density and height were documented before and after the burns. Before burning, Rosa nutkana (Nootka rose) was the most abundant woody species at both sites. In 1988, burns were significantly more intense, produced more heat per unit area at Fisher Butte than at Rose Prairie, and were fairly complete, with 37% and 35% woody biomass consumption, respectively. In 1989, burns were spotty; only 11% of woody biomass was consumed at Fisher Butte. The one-burn treatment did not affect R. nutkana density in 1 × 15 m transects at either site; the two-burn treatment significantly increased its density in three of the five communities sampled. Burning significantly reduced height growth by eliminating taller individuals while stimulating sprouts from belowground tissues. Redistribution of R. nutkana and trees into shorter height classes indicates the possibility of reducing the visual dominance of woody species if periodic burns were conducted in native Willamette Valley prairie. The low-intensity burns in this study were sufficient to remove the woody shoots under 3 m tall but did not reduce their capacity to regenerate and did not reduce the density of woody species. After decades of fire suppression, two burns were not sufficient to reestablish the desired balance between native herbaceous and woody species or to reduce the presence of introduced woody species. A long-term commitment to the reintroduction of fire as a management tool will be required to maintain native wetland prairies in the Willamette Valley. [ABSTRACT FROM AUTHOR]

Losses of grasslands have been largely attributed to widespread land‐use changes, such as conversion to row‐crop agriculture. The remaining tallgrass prairie faces further losses due to biological invasions by non‐native plant species, often with resultant ecosystem degradation. Of critical concern for conservation, restoration of native grasslands has been met with little success following eradication of non‐native plants. In addition to the direct and indirect effects of non‐native invasive plants on beneficial soil microbes, management practices targeting invasive species may also negatively affect subsequent restoration efforts. To assess mechanisms limiting germination and survival of native species and to improve native species establishment, we established six replicate plots of each of the following four treatments: (1) inoculated with freshly collected prairie soil with native seeds; (2) inoculated with steam‐pasteurized soil with native seeds; (3) noninoculated with native seeds; or (4) noninoculated/nonseeded control. Inoculation with whole soil did not improve seed germination; however, addition of whole soil significantly improved native species survival, compared to pasteurized soil or noninoculated treatments. Inoculation with whole soil significantly decreased reestablishment of non‐native invasive Bothriochloa bladhii (Caucasian bluestem); at the end of the growing season, plots receiving whole soil consisted of approximately 30% B. bladhii cover, compared to approximately 80% in plots receiving no soil inoculum. Our results suggest invasion and eradication efforts negatively affect arbuscular mycorrhizal hyphal and spore abundances and soil aggregate stability, and inoculation with locally adapted soil microbial communities can improve metrics of restoration success, including plant species richness and diversity, while decreasing reinvasion by non‐native species. [ABSTRACT FROM AUTHOR]

Restoring the diversity of plant species found in remnant communities is a challenge for restoration practitioners, in part because many reintroduced plant species fail to establish in restored sites. Legumes establish particularly poorly, perhaps because they depend on two guilds of soil microbial mutualists, rhizobial bacteria and arbuscular mycorrhizal (AM) fungi, that may be absent from restored sites. We tested the effect of soil microorganisms from remnant and restored prairies on legume growth by inoculating seedlings of Lespedeza capitata, Amorpha canescens, and Dalea purpurea with soil from 10 restored prairies and 6 remnant (untilled) prairies from southwest Michigan. We generally found support for the hypothesis that restored prairie soils lack microbes that enhance prairie plant growth, although there was variation across species and mutualist guilds. All three legumes grew larger and two legumes (Lespedeza and Amorpha) produced more nodules when inoculated with soil from remnant prairies, suggesting that low quantity and/or quality of rhizobial partners may limit the establishment of those species in restored prairies. In contrast, no legume experienced greater root colonization by AM fungi in remnant prairie soils, suggesting equivalent quantity (but not necessarily quality) of fungal partners in remnant and restored prairie soils. We detected no evidence of spontaneous recovery of the community of beneficial soil microbes in restorations. These results suggest that the absence of rhizobia, a largely overlooked component of prairie soils, could play a strong role in limiting restored prairie diversity by hindering legume establishment. Active reintroduction of appropriate rhizobial strains could enhance prairie restoration outcomes. [ABSTRACT FROM AUTHOR]

Intensive agriculture has led to widespread losses of native grasslands. Restoration projects are trying to reestablish native communities. However, the poor quality and altered food webs of former agricultural soils act as barriers to establishing diverse plant communities. Soil amendments such as biochar have been used to improve soil quality and increase crop yield, but little research has been on biochar in restoration settings. Eastern Washington University is attempting to restore a former wheat field to native Palouse prairie vegetation. In this study, we compared (1) soil abiotic properties and food webs between Palouse prairie remnants and Eastern Washington University's (EWU) restoration site and (2) tested whether biochar can move soil conditions at EWU's restoration site closer to those of remnant sites. We compared soils from three Palouse prairie remnants and EWU's restoration site, and compared soils at the restoration site that were treated with different levels of biochar. Soil nematodes were extracted and sorted to functional groups as an assay of the structure and functional diversity of the soil food web. The soil at EWU's restoration site had significantly lower nematode abundance, pH, and organic matter compared to prairie remnants. In addition, nematode abundance and pH increased significantly at the EWU site with the addition of biochar, both increasing to conditions similar to what is found at the prairie remnant sites. These results suggest biochar can improve some soil conditions in former agricultural lands even prior to native plant restoration. [ABSTRACT FROM AUTHOR]

One common goal of habitat restoration and reconstruction is to reinstate the biodiversity found at intact reference sites. However, few researchers have examined whether these practices reinstate communities of flower‐visiting insects. This is unfortunate, as anthropogenically mediated declines in flower visitors, including bees (the primary pollinators for most terrestrial ecosystems), beetles, flies, and butterflies, have been reported worldwide. Biodiversity declines may be especially severe in North America's tallgrass prairie, a once‐vast grassland that has experienced severe destruction and degradation due to agricultural conversion. As such, we assessed the structure of forb and flower‐visiting insect communities as a whole and two subsets of the flower visitor community—bees and phytophagous beetles—across five tallgrass prairie remnants and five reconstructed prairies (former crop fields) in Kansas from 2013 to 2015. Remnant prairies had significantly higher forb diversity and differed significantly in forb composition, compared to reconstructed prairies. Despite the dissimilarities in forb community structure, there were no differences in flower visitor diversity or abundance between remnants and reconstructed prairies. However, when considered separately, bee communities exhibited significantly greater variability in composition on reconstructed prairies, likely due to the abundance of generalist bee species visiting non‐native legumes at two reconstructed prairies. Our work provides evidence that prairie habitat reconstruction is a valuable tool for reestablishing flower‐visiting insect communities and also emphasizes the considerable role that non‐native species may play in structuring grassland plant–bee interactions. [ABSTRACT FROM AUTHOR]

Grazing as a management tool is often intended to alter plant community dynamics through preferential foraging. Bison diet in the western United States has been well studied, especially in short and mixed grass remnant prairies. However, there is little known about what bison consume in restored and tallgrass prairies. As bison reintroductions are used more commonly in eastern tallgrass prairies, it is important to understand their diet to predict future impacts on prairie plant communities. This study aims to understand bison diet across different seasons, and asks whether diet differs among male and female, and differently aged bison. We used stable isotope analysis to quantify δ13C and δ15N in plants and used a Bayesian isotope mixing model to estimate bison diet. We found bulls relied more heavily on C4 plants and wetland plants than cows, which relied more heavily on forbs, but no differences in diet between ages. Our analysis shows that bison primarily grazed on C4 grasses throughout the late spring and summer. However, bison foraged more on wetland species and forbs in the late summer and fall. This change in diet could have implications for wetland species and habitats, through dung inputs and trampling. The relatively high reliance on forbs for nearly one‐third of bison diet could mean intended impacts of reintroduced bison such as increased plant diversity through preferential grazing on grasses could be dampened. Managers reintroducing bison to restored prairie ecosystems should ensure adequate wetland and forb species, in addition to a mix of grasses. [ABSTRACT FROM AUTHOR]

Prairie reconstruction has become a common method for reestablishing tallgrass prairie communities in the central United States. With the objective of creating plant communities that approximate remnant (reference) prairies, managers are interested in identifying: (1) best methods for reconstructing reference community conditions; (2) the rate of change in plant communities through time following reconstruction; and (3) species present in remnant communities but missing from reconstructed communities. This information is important in the development of adaptive management strategies during active reconstruction. We used a chronosequence approach to assess the success of two reconstruction methods in emulating local, reference remnant prairie plant communities. We compared broadcast dormant seeding following two types of site preparation, agricultural cropping (Crop) or herbicide control in existing grass assemblages (Grass), and remnant communities. The Crop site preparation method resulted in a rapid increase in richness shortly following seeding. Although more similar to remnant assemblages initially, the Grass method took longer for mean coefficient of conservatism and floristic quality index to approach conditions of the reference communities. However, neither method resulted in plant community compositions that converged with the reference through time. Further, indicator species analysis identified a diverse assemblage of species lacking from the reconstructed prairies. These results suggest the need to develop management strategies for establishing the "missing" species during reconstruction and provide further support for protection and conservation of existing remnant prairies. [ABSTRACT FROM AUTHOR]

This study investigated the relationship among plant diversity, production, stability, and susceptibility to invasion in restored northern tall grass prairies (United States). The experiment consisted of 50 species mixtures fertilized with N or P, at high or low levels. Results from the past 5 years were as follows: (1) aboveground biomass increased and year-to-year variability declined with increases in plant species and functional form richness, mostly as a result of substantial increases in minimum biomass (maximum biomass was unaffected). (2) Aboveground biomass and biomass stability increased when the species in the mixture had: (a) high relative growth rates, root density, root surface area per unit of root biomass, uptake rates of N or P per unit of root surface area, and N use efficiency and (b) low root to shoot ratio. (3) Invasion of nonseeded species declined with increases in plant species and functional form richness. (4) The results from this experiment did not provide a single specific criterion for selecting an optimal species mixture. However, if the objectives of the restoration were simply to achieve an aboveground biomass variability that is less than that of growing-season precipitation, then the seed mixtures need to have a minimum of nine species and three functional forms. [ABSTRACT FROM AUTHOR]

Climate change threatens the long‐term survival of highly fragmented habitats such as North American tallgrass prairie. De novo plantings into former agricultural sites can contribute to efforts to conserve prairie biodiversity, but past planting practice (including our own) has focused on the use of local species and genotypes. Climate change makes this "local‐only" practice obsolete because of rapidly shifting species' ranges. We propose that new prairie plantings incorporate assisted migration at the community level; all species and genotypes that are viable in the changed climate and potentially could reach the site in an unfragmented landscape should be considered for inclusion. Selecting and sourcing species for climate‐appropriate restorations is possible with minimal additional cost or expertise. Based on best‐available estimates of current and future climate, species richness of future prairie plantings at our Minnesota study site could be increased by over one‐third (26 new species). Potential risks to such extensive use of assisted migration are offset by the drastic conservation challenge of highly fragmented communities under climate change. [ABSTRACT FROM AUTHOR]

Decision‐making is central to restoration practice, from the framing of objectives to the employment of tools and strategies. Yet, it remains largely unclear how decisions are made during restoration and this limits understanding of how restoration managers design and implement restoration projects and what restoration approaches may be most effective. This is true for tallgrass prairies in the Midwestern United States, which are commonly restored through seed sowing. To understand how managers make decisions during prairie restoration, we used a mixed‐methods approach including interviews, a focus group, and an online survey, to ask managers about: restoration objectives, factors influencing seed mix design, tools and resources used in seed mix design, seeding methods, and monitoring. Respondents considered biodiversity the most important restoration objective, and the most important biodiversity measures were species richness and functional group diversity. Seed mix design was influenced by seed availability. We identified 141 taxa that managers would like to use in restoration, but cannot due to factors like cost, availability, or problems with germination or establishment. Managers most frequently used their own experience and consultation with other practitioners to guide seed mix design; and commonly used tools developed within their organization. Most managers agreed that monitoring was important for assessing restoration outcomes, but were unable to devote enough time to monitoring. These findings illustrate opportunities for partnerships, among restoration managers, and among managers, seed producers, and researchers. [ABSTRACT FROM AUTHOR]

Little of the historical extent of tallgrass prairie ecosystems remains in North America, and therefore there is strong interest in restoring prairies. However, slow‐growing prairie plants are initially weak competitors with the fast‐growing yet short‐lived weedy plant species that are typically abundant in recently established prairie restorations. One way to aid establishment of slow‐growing plant species is through adding soil amendments to prairie restorations before planting. Arbuscular mycorrhizal (AM) fungi form mutualisms with the roots of most terrestrial plants and are particularly important for the growth of slow‐growing prairie plant species. As prairie ecosystems are adapted to fires that leave biochar (charred organic material) in the soil, adding biochar as well as AM fungal strains from undisturbed remnant prairies into the soil of prairie restorations may improve restoration outcomes. Here, we test this prediction during the first four growing seasons of a prairie restoration. When prairie plant seedlings were inoculated prior to planting into the field with AM fungi derived from remnant prairies, that one‐time inoculation significantly increased growth of five of the nine tested plant species through at least two growing seasons. This long‐term benefit of AM fungal inoculation was unaffected by biochar addition to the soil. Biochar application rates of at least 10 tons/ha significantly decreased Coreopsis tripteris growth but acted synergistically with AM fungal inoculation to significantly improve survival of Schizachyrium scoparium. Overall, inoculation with native AM fungi can help promote prairie plant establishment, but concomitant use of biochar soil amendments had relatively little effect. [ABSTRACT FROM AUTHOR]

Site‐specific conditions, climate, and management decisions all dictate the establishment and composition of desired plant communities within grassland restorations. The uncertainty, complexity, and large size of grassland restorations necessitate monitoring plant communities across spatial and temporal scales. Remote sensing with unmanned aerial vehicles (UAVs) may provide a tool to monitor restored plant communities at various scales, but many potential applications are still unknown. In a tallgrass prairie restoration located in Franklin Grove, IL, we used UAV‐based multispectral imagery to assess the ability of spectral indices to predict ecological characteristics (plant community, plant traits, soil properties) in the summer of 2017. Using 19 sites, we calculated the moments of 26 vegetation indices and four spectral bands (green, red, red edge, near infrared). Models based on each moment and a model with all moments were estimated using ridge regression with model training based on a subset of 15 sites. Each tested for significant error reduction against a null model. We predicted mean graminoid cover, mean dead aboveground biomass, mean dry mass, and mean soil K with significant reductions in cross‐validated root mean square error. Averaged coefficients determined from cross‐validation of ridge regression models were used to develop a final predictive model of the four successfully predicted ecological characteristics. Graminoid cover and soil potassium were successfully predicted in one of the sites while the other two were not successfully predicted in any site. This study provides a path toward a new level of ease and precision in monitoring community dynamics of restored grasslands. [ABSTRACT FROM AUTHOR]