Recovery of Native Plant Community Characteristics on a Chronosequence of Restored Prairies Seeded into Pastures in West‐Central Iowa

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.     

Dominant Grasses Suppress Local Diversity in Restored Tallgrass Prairie

Warm‐season (C₄) grasses commonly dominate tallgrass prairie restorations, often at the expense of subordinate grasses and forbs that contribute most to diversity in this ecosystem. To assess whether the cover and abundance of dominant grass species constrain plant diversity, we removed 0, 50, or 100% of tillers of two dominant species (Andropogon gerardii or Panicum virgatum) in a 7‐year‐old prairie restoration. Removing 100% of the most abundant species, A. gerardii, significantly increased light availability, forb productivity, forb cover, species richness, species evenness, and species diversity. Removal of a less abundant but very common species, P. virgatum, did not significantly affect resource availability or the local plant community. We observed no effect of removal treatments on critical belowground resources, including inorganic soil N or soil moisture. Species richness was inversely correlated with total grass productivity and percent grass cover and positively correlated with light availability at the soil surface. These relationships suggest that differential species richness among removal treatments resulted from treatment induced differences in aboveground resources rather than the belowground resources. Selective removal of the dominant species A. gerardii provided an opportunity for seeded forb species to become established leading to an increase in species richness and diversity. Therefore, management practices that target reductions in cover or biomass of the dominant species may enhance diversity in established and grass‐dominated mesic grassland restorations.     

Native–Exotic Species Richness Relationships Across Spatial Scales in a Prairie Restoration Matrix

In highly invaded ecosystems, restoration of native plant communities is dependent upon reducing exotic species relative to native species. Even so, in monitoring, the native–exotic species richness ratio has been shown to be scale‐dependent. Measurement at small spatial scales (<1 m²) can reveal a negative native–exotic richness relationship, where niche occupation may prevent invasion. Conversely, at larger scales, a positive correlation may exist, where environmental heterogeneity and equally favorable conditions may drive native–exotic relationships. Here, we compare slopes of native–exotic relationships across spatial scales in a prairie undergoing active restoration. The observed native–exotic richness ratios varied considerably over scales ranging from 1 to 1,000 m², emphasizing the importance of choosing a measurement scale that is most pertinent to the treatment and ecological mechanism used to evaluate restoration success. Our native–exotic richness slopes were positive over all scales, but lower than would be expected in a random community assembly, suggesting the influence of niche‐based competition. Correspondingly, our native–exotic cover slope was more negative than a null model; however, areas of frequent fire treatments showed a significant deviation from null only for richness, indicating that burning may enhance native–exotic competitive dynamics for number of species but not cover. The negative native–exotic cover relationships appear to be driven in this system mainly by exotic graminoids, across burn treatments and native functional groups, supporting the concept that frequent burning can alter the dominant competitive mechanism from coverage of these exotic grasses to an improved environment for germination and dispersal of more native species.     

Productivity and Subordinate Species Response to Dominant Grass Species and Seed Source during Restoration

Grasses can be important regulators of species diversity and ecosystem processes in prairie systems. Although C₄ grasses are usually assumed to be ecologically similar because they are in the same functional group, there may be important differences among species or between seed sources that could impact restorations. I tested whether C₄ grass species identity, seed source, or grass species richness scales to influence aboveground net primary productivity (ANPP), resistance to weed invasion, or establishment of subordinate prairie species during restoration. Plots in western Iowa, United States, were planted with equal‐sized transplants of one of five common grass species (Panicum virgatum L., Sorghastrum nutans (L.) Nash, Andropogon gerardii Vitman, Schizachyrium scoparium (Michx.) Nash, and Bouteloua curtipendula (Michx.) Torrey) either from local seed or from cultivar seed sources. These plots were compared to plots containing all five species in mixture and to nonplanted plots. Differences in ANPP were found among species but not between cultivars and noncultivars or between monocultures and mixtures. Panicum virgatum, S. nutans, and S. scoparium were more productive than A. gerardii and B. curtipendula. Weed invasion was much higher when plots were not planted with grasses. Schizachyrium scoparium allowed greater establishment of subordinant prairie species than all other focal grass species. There were two separate mechanisms by which grasses suppressed prairie species establishment either (1) by growing tall and capturing light or (2) by quickly filling in bare space by spreading horizontally through rhizome growth in short species. These results suggest that high ANPP can be found with noncultivar plantings during the first 2 years after planting and that subordinate species establishment is most likely when shorter bunchgrasses such as S. scoparium are dominant.     

Using prairie restoration to curtail invasion of Canada thistle: the importance of limiting similarity and seed mix richness

Theory has predicted, and many experimental studies have confirmed, that resident plant species richness is inversely related to invisibility. Likewise, potential invaders that are functionally similar to resident plant species are less likely to invade than are those from different functional groups. Neither of these ideas has been tested in the context of an operational prairie restoration. Here, we tested the hypotheses that within tallgrass prairie restorations (1) as seed mix species richness increased, cover of the invasive perennial forb, Canada thistle (Cirsium arvense) would decline; and (2) guilds (both planted and arising from the seedbank) most similar to Canada thistle would have a larger negative effect on it than less similar guilds. Each hypothesis was tested on six former agricultural fields restored to tallgrass prairie in 2005; all were within the tallgrass prairie biome in Minnesota, USA. A mixed-model with repeated measures (years) in a randomized block (fields) design indicated that seed mix richness had no effect on cover of Canada thistle. Structural equation models assessing effects of cover of each planted and non-planted guild on cover of Canada thistle in 2006, 2007, and 2010 revealed that planted Asteraceae never had a negative effect on Canada thistle. In contrast, planted cool-season grasses and non-Asteraceae forbs, and many non-planted guilds had negative effects on Canada thistle cover. We conclude that early, robust establishment of native species, regardless of guild, is of greater importance in resistance to Canada thistle than is similarity of guilds in new prairie restorations.     

Phylogenetically and functionally diverse species mixes beget diverse experimental prairies,whether from seeds or plugs

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.     

Biodiversity responses to land‐use and restoration in a global biodiversity hotspot: Ant communities in Brazilian Cerrado

Given that land‐use change is the main cause of global biodiversity decline, there is widespread interest in adopting land‐use practices that maintain high levels of biodiversity, and in restoring degraded land that previously had high biodiversity value. In this study, we use ant taxonomic and functional diversity to examine the effects of different land uses (agriculture, pastoralism, silviculture and conservation) and restoration practices on Cerrado (Brazilian savanna) biodiversity. We also examine the extent to which ant diversity and composition can be explained by vegetation attributes that apply across the full land management spectrum. We surveyed vegetation attributes and ant communities in five replicate plots of each of 13 land‐use and restoration treatments, including two types of native vegetation as reference sites: cerrado sensu stricto and cerradão. Several land‐use and restoration treatments had comparable plot richness to that of the native reference habitats. Ant species and functional composition varied systematically among land‐use treatments following a gradient from open habitats such as agricultural fields to forested sites. Tree basal area and grass cover were the strongest predictors of ant species richness. Losses in ant diversity were higher in land‐use systems that transform vegetation structure. Among productive systems, therefore, uncleared pastures and old pine plantations had similar species composition to that occurring in cerrado sensu stricto. Restoration techniques currently applied to sites that were previously Cerrado have focused on returning tree cover, and have failed to restore ant communities typical of savanna. To improve restoration outcomes for Cerrado biodiversity, greater attention needs to be paid to the re‐establishment and maintenance of the grass layer, which requires frequent fire. At the broader scale, conservation planning in agricultural landscapes, should recognize the value of land‐use mosaics and the risks of homogenization.     

Mycorrhizal fungal spore community structure in a manipulated prairie

Most plant communities support a diverse assemblage of arbuscular mycorrhizal fungi (AMF). AMF communities have the potential to affect plant community structure and vice versa. We examined AMF sporulation in a 4.5‐ha reconstructed prairie in Eau Claire County, Wisconsin. In fall 2003, the site was planted with varied numbers and combinations of native prairie species from four functional guilds: C₃ grasses/sedges, C₄ grasses, legume, and nonleguminous forbs. We hypothesized that more diverse plant seeding mixtures would promote AMF diversity. To examine the interaction between plant and fungal communities, plots were divided and subplots treated with the fungicide chlorothalonil to suppress AMF, enriched with ammonium nitrate fertilizer, treated with both fungicide and nitrogen, or remained untreated (control). Soil samples were collected during the summers of 2004, 2006, and 2007 from each subplot. Spores of AMF were extracted, identified to species, and enumerated. Initial plant seeding diversity did not significantly influence spore abundance, fungal diversity, plant productivity, or plant richness 4 years after establishment. Fungal species richness was positively, but weakly, correlated with plant productivity (r² = 0.11) and plant richness (r² = 0.09). Fungal community composition changed significantly over time; nitrogen addition, fungicide application, and site characteristics also shaped community composition. After 4 years of treatment, nitrogen and fungicide reduced AMF richness, changed sporulation patterns among AMF taxa, and reduced diversity and productivity in plant communities. Divergence in AMF community is being mirrored by changes in the plant community independent of initial seeding treatments, though causation could not be determined.     

Wild bee community change over a 26‐year chronosequence of restored tallgrass prairie

Restoration efforts often focus on plants, but additionally require the establishment and long‐term persistence of diverse groups of nontarget organisms, such as bees, for important ecosystem functions and meeting restoration goals. We investigated long‐term patterns in the response of bees to habitat restoration by sampling bee communities along a 26‐year chronosequence of restored tallgrass prairie in north‐central Illinois, U.S.A. Specifically, we examined how bee communities changed over time since restoration in terms of (1) abundance and richness, (2) community composition, and (3) the two components of beta diversity, one‐to‐one species replacement, and changes in species richness. Bee abundance and raw richness increased with restoration age from the low level of the pre‐restoration (agricultural) sites to the target level of the remnant prairie within the first 2–3 years after restoration, and these high levels were maintained throughout the entire restoration chronosequence. Bee community composition of the youngest restored sites differed from that of prairie remnants, but 5–7 years post‐restoration the community composition of restored prairie converged with that of remnants. Landscape context, particularly nearby wooded land, was found to affect abundance, rarefied richness, and community composition. Partitioning overall beta diversity between sites into species replacement and richness effects revealed that the main driver of community change over time was the gradual accumulation of species, rather than one‐to‐one species replacement. At the spatial and temporal scales we studied, we conclude that prairie restoration efforts targeting plants also successfully restore bee communities.     

Traits,neighbors, and species performance in prairie restoration

Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon, USA. Methods: Twenty‐eight native species, representing three functional groups, were sown in seven different combinations. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and regression techniques used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity; the functional group identity of neighboring species also influenced species' cover and the relationships between traits and cover. Species' establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi‐trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 d and seed mass were strongly related to cover. Conclusions: Multiple‐trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species and the other species being sown may need to be taken into account when making predictions.     

Plant community responses to bison reintroduction on the Northern Great Plains,United States: a test of the keystone species concept

Keystone species restoration, or the restoration of species whose effect on an ecosystem is much greater than their abundance would suggest, is a central justification for many wildlife reintroduction projects globally. Following restoration, plains bison (Bison bison L.) have been identified as a keystone species in the tallgrass prairie ecoregion, but we know of no research to document similar effects in the mixed‐grass prairie where restoration efforts are ongoing. This study addresses whether Northern Great Plains (NGP) mixed‐grass prairie plant communities exhibit traits consistent with four central keystone effects documented for bison in the tallgrass prairie. We collected species composition, diversity, abundance, bare ground cover, and plant height data in three treatments: where livestock (Bos taurus L.) continuously grazed, livestock were removed for 10 years, and bison have been introduced and resident for 10 years. We observed mixed support for bison acting as keystone species in this system. Supporting the keystone role of bison, we observed higher species richness and compositional heterogeneity (β‐diversity) in the bison treatment than either the livestock retention or livestock removal treatments. However, we observed comparable forb, bare ground, and plant height heterogeneity between bison‐restored sites and sites where livestock were retained, contradicting reported keystone effects in other systems. Our results suggest that after 10 years of being restored, bison partially fulfill their role as a keystone species in the mixed‐grass prairie, and we encourage continued long‐term data collection to evaluate their influence in the NGP.     

High Plant Richness in Prairie Reconstructions Support Diverse Leafhopper Communities

A primary reason for restoring plant communities is to increase biodiversity to previous levels. It is expected that restoring land with greater plant diversity will increase biodiversity at higher trophic levels, but high diversity seed mixes are expensive. In this study, we used one insect family, leafhoppers (Hemiptera: Cicadellidae) to assess the difference in leafhopper communities that result from establishing high compared with low plant richness restorations. We tested the hypotheses that: (1) the added effort of a high richness restoration leads to measurable increases in both diversity and richness of leafhoppers; and (2) that leafhopper community composition is more similar to remnant prairies in high richness than in low plant richness restorations. We found that higher plant richness led to 3‐ to 7‐fold increases in leafhopper and prairie‐dependent leafhopper diversity and richness in restorations. Leafhopper communities in high richness restorations were not more similar to remnant prairies, rather they were distinct among high and low richness restorations and prairie interior. Leafhopper richness and diversity correlated with plant richness, and leafhopper community composition differed among plant community assemblages, but not with the occurrence of single plant species. For our sites, species‐rich restorations provided better quality habitat for leafhoppers that was comparable to remnant prairie. Our results suggest that restorations with high plant species richness better support animal food webs.     

Tallgrass prairie restoration: implications of increased atmospheric nitrogen deposition when site preparation minimizes adventive grasses

Site preparation designed to exhaust the soil seedbank of adventive species can improve the success of tallgrass prairie restoration. Despite these efforts, increased rates of atmospheric nitrogen (N) deposition over the next century could potentially promote the growth of nitrophilic, adventive species in tallgrass restoration projects. We used a field experiment to examine how N addition affected species composition and plant productivity over the first 3 years of a tallgrass prairie restoration that was preceded by the planting of glyphosate‐resistant crops and multiple applications of glyphosate to exhaust the pre‐existing seedbank. We predicted that N addition would increase the percent cover of adventive plant species not included in the original seeding. Contrary to our prediction, only the cover of native species increased with N addition; native non‐leguminous forbs increased substantially, with Conyza canadensis (a weedy native species not part of the restoration seed mix) exploiting the combination of high N and bare ground in the first year, and non‐leguminous forbs (in particular Monarda fistulosa) and native C₃ grasses, all of which were seeded, increasing with N addition by the third year. Native legumes was the only functional group that exhibited lower cover in N addition plots than in control plots. There was no significant response by native C₄ grasses to N addition, and adventive grasses remained mostly absent from the plots. Overall, our results suggest that site pre‐treatment with herbicide may continue to be effective in minimizing adventive grasses in restored tallgrass prairie, despite future increases in atmospheric N deposition.     

Revegetation of Motorway Slopes Using Different Seed Mixtures

Motorway slopes cover large areas and could, if properly managed, partially compensate for the loss of natural habitats and connect remnant populations of target species. One of the main problems on such slopes is soil erosion; therefore, quick and stable revegetation is essential. Two widely used commercial seed mixtures were sown and tested to determine which one is better for restoration of motorway slopes. Both mixtures contained CSR strategists (“competitive stress‐tolerant ruderals”) but one included nurse species (Lolium perenne, L. multiflorum, Trifolium spp.), whereas the other did not. Both treatments were sampled every year over a period of 6 years and analyzed for species richness, diversity, similarity, and plant cover. The research took place in the sub‐Mediterranean part of Slovenia, where low precipitation during summer is characteristic. It was found that the seed mixture with stress‐tolerating species but without nurse species resulted in a smoother succession to a species‐rich grassland with stable cover. Succession was, by contrast, delayed in the mixture with nurse‐plants because they inhibited the establishment of the stress‐tolerating species and target species, respectively.     

Sowing density effects and patterns of colonization in a prairie restoration

A cost‐effective approach in plant restorations could be to increase sowing density for species known to be challenging to establish, while reducing sowing density for species that easily colonize on their own. Sowing need not occur evenly across the site for rapidly dispersing species. We explored these issues using a prairie restoration experiment on a high‐school campus with three treatments: plots sown only to grasses (G plots), to grasses and forbs (GF1), and to grasses and forbs with forbs sown at twice the density (GF2). In year 2, GF1 and GF2 plots had higher diversity than G plots, as expected, but GF2 treatments did not have twice the sown forb cover. However, high forb sowing density increased forb richness, probably by reducing stochastic factors in establishment. Cover of nonsown species was highest in G plots and lowest in GF2 plots, suggesting suppressive effects of native forbs on weedy species. Colonization of G plots by two sown forbs (Coreopsis tinctoria and Rudbeckia hirta) was apparent after 2.5 years, providing evidence that these species are self‐sustaining. Colonization was greater in edges than in the central areas of G plots. Through construction of establishment kernels, we infer that the mean establishment distance was shorter for R. hirta (6.7 m) compared to C. tinctoria (21.1 m). Our results lead us to advocate for restoration practices that consider not only seed sowing but also subsequent dispersal of sown species. Furthermore, we conclude that restoration research is particularly amenable for outdoor education and university‐high school collaborations.     

Restoration of Species‐Rich,Nutrient‐Limited Mountain Grassland by Mowing and Fertilization

Mowing and management to reduce nutrient levels have often been successfully used to restore species‐rich grasslands in various parts of Europe. However, such treatments have failed to restore the species‐rich Central European mountain grasslands dominated by Polygonum bistorta. P. bistorta builds an extensive underground rhizome system that monopolizes available nutrients in these nutrient‐poor grasslands, enabling this species to persist at high densities even in the presence of mowing. Therefore, we tested a restoration approach using a factorial combination of fertilization and mowing, as well as a litter removal treatment. The experiment was run over 5 years and species composition response to these treatments was recorded at two spatial scales. Mowing suppressed flowering and cover of P. bistorta and promoted target grassland species and richness. Fertilization prevented nutrient impoverishment and increased height and dominance of the broad‐leaved grasses with which many species‐rich grassland herbs could coexist. The additive effect of the mowing/fertilization treatments was strong enough to act as a driver of P. bistorta suppression and associated community change. The litter removal treatment, however, had little effect on plant composition. The experiment demonstrates that in nutrient‐limited grasslands, increasing nutrient levels in addition to mowing to manage competition for light can be used to control dominants. This contrasts with restoration of systems where after abandonment increased nutrient levels lead to the establishment of tall dominants that suppress other species by competition for light.     

Influence of soil properties on coastal sandplain grassland establishment on former agricultural fields

The decline in species‐rich grasslands across the United States has increased the importance of conservation and restoration efforts to preserve the biodiversity supported by these habitats. Abandoned agricultural fields often provide practical locations for the reestablishment of species‐rich grasslands. However, these fields often retain legacies of agriculture both in their soils, which may have higher pH and nitrogen (N) contents than soils that were never farmed, and in their plant communities, which are dominated by non‐native species and poor in native seed stock. We considered methods of reversing these legacies to create native‐species‐rich grassland on former agricultural land. We tested seeding and tilling combined with additions of sulfur (S), carbon (C), N or water to establish diverse sandplain grassland vegetation on an old field on Martha's Vineyard, Massachusetts. We measured soil pH, extractable nitrate and ammonium, and total and native species richness and native species cover for 5 years after treatment. S additions lowered pH to values typical of never‐tilled sandplain ecosystems and increased native species cover, but had no effect on species richness. C, N, and water additions had no significant effects on the soil or vegetation. Seeding and tilling were more effective at restoring native species richness than any soil amendments and indicated a greater importance of biotic factors compared with soil conditions in promoting sandplain vegetation establishment. S amendment accelerated establishment of native species cover for several years but the effect of S additions compared with seeding and tilling alone declined over time.     

Invasion by Non-Native Annual Grasses: The Importance of Species Biomass, Composition, and Time Among California Native Grasses of the Central Valley

The Central Valley of California is noted for its dearth of remnant native grass populations and for low native grass seedling establishment within grasslands now dominated by non‐native annual species. In contrast, remnant populations are common along the coast, and studies have shown an ability for seedlings and adults to compete with non‐native annual grasses. The invasibility of well‐established populations of native grasses in the Central Valley remains unclear. The objectives of this study were to compare the invasibility of native grasses differing in density and species composition and, given the species in this study, to assess the ability of mixes with greater species richness to resist invasion relative to their abilities in monoculture. In the Sacramento Valley of California, six species of native grasses were planted at three densities in monospecific and mixed‐species plots. Percent cover of native perennial and non‐native annual grasses was measured in years 2 and 3, and biomass was sampled in year 5. Native grass biomass and, to a lesser extent, species composition were important in explaining variation in non‐native grass invasibility in the fifth year. Species‐rich treatments did not experience less invasion than would be expected by the proportional invasibility of each species in monoculture. However, invasibility of plots consisting of slower growing, shorter statured species decreased over time, suggesting a successional benefit to diverse communities. This study demonstrates that established stands of native grasses in the Sacramento Valley can resist invasion by non‐native annual grasses and that stand biomass is a particularly important factor in determining invasibility.     

Use of sheep grazing in the restoration of semi‐natural meadows in northern Finland

Abstract. The biodiversity of species‐rich semi‐natural meadows is declining across Europe due to ceased management. In this study we aimed to find out how successfully the local species richness of an overgrown semi‐natural mesic meadow could be restored by sheep grazing after a long period of abandonment. The cover of vascular plant species in grazed plots and ungrazed exclosures was studied for five years and the responses of different functional plant groups were followed (herbs vs grasses, tall vs short species, species differing in flowering time, species representing different Grime's CSR strategies and species indicative of rich vs poor soil). Grazing increased species number by nearly 30%. On grazed plots the litter cover practically disappeared, favouring small herbs such as Rhinanthus minor, Ranunculus acris, Trifolium pratense and the grass Agrostis capillaris. Grazing decreased the cover of the late flowering tall herb Epilobium angustifolium but had no effect on the abundance of the early flowering tall herbs Anthriscus sylvestris or Geranium sylvaticum. We suggest that to succeed in restoration it is useful to determine the responses of different functional plant groups to grazing. Grassland managers need this information to optimize the methods and timing of management used in restoration. Additional management practices, such as mowing, may be needed in mesic meadows to decrease the dominance of tall species. The availability of propagules seemed to restrict further increase of species richness in our study area.     

Effect of Hay Transfer on Long-Term Establishment of Vegetation and Grasshoppers on Former Arable Fields

The transfer of seed‐containing hay is a restoration measure for the introduction of plant species of local provenance. We investigated the effect of hay transfer on species richness and on long‐term establishment of target plant and grasshopper species on former arable fields with and without topsoil removal in comparison to reference sites in a nature reserve. Plant species richness, the number of target plant species, and Red List plant species were significantly positively affected by hay transfer, both on the scale of whole restoration fields and on permanent plots of 4 m². Eight years after the start of the restoration, only few of the transferred plant species had disappeared and some target species were newly found. Grasshoppers were affected not by hay transfer but by topsoil removal. The proportion of target grasshopper and plant species and Red List grasshopper species was higher on topsoil removal sites with low standing crop and high cover of bare soil than on sites without soil removal. On topsoil removal sites without hay, however, plant species richness was very low because of the slow natural dispersal of the target species. Vegetation and grasshopper communities still differed between restoration fields and the nature reserve. Nevertheless, our results indicate that the transfer of autochthonous seed‐containing hay is a successful method to establish species‐rich grasslands with a high proportion of target species.