Establishment of tree seedlings in the understory of restoration plantations: natural regeneration and enrichment plantings

Little is known about the potential of restoration plantations to provide appropriate understory conditions to support the establishment of seeds arriving from neighboring native forests. In this article, we investigated how seedling establishment is affected in the understory of restoration sites of different ages and assessed some of the potential environmental factors controlling this ecological process. We first compared the density and richness of native tree seedlings among 10‐, 22‐, and 55‐year‐old restoration plantations within the Atlantic Forest region of southeastern Brazil. Then, we undertook a seed addition experiment in each study site, during the wet season, and compared seedling emergence, survival, and biomass on local versus old‐growth forest soil (transferred from a reference ecosystem), in order to test whether local substrate could hamper seedling establishment. As expected, the oldest restoration site had higher density and richness of spontaneously regenerating seedlings. However, seedling establishment was less successful both in the oldest restoration planting and using substrate transferred from a reference ecosystem, where emergence and survival were lower, but surviving seedlings grew better. We attribute these results to lower light availability for seedlings in the understory of the oldest site and speculate that higher incidence of pathogens on old‐growth forest soil may have increased seedling mortality. We conclude that the understory of young restoration plantations provides suitable microsite conditions at the early establishment phases for the spontaneous regeneration or enrichment planting of native trees.     

Widespread resistance of Mediterranean island ecosystems to the establishment of three alien species

Although some invasive plants are cosmopolitan, not all ecosystems are invaded to the same degree. Yet there is little experimental work on how ecosystem resistance to invasion at the establishment phase differs among ecosystems. We conducted two field sowing experiments in two consecutive years to examine establishment of the deciduous tree Ailanthus altissima, the succulent subshrub Carpobrotus spp. and the annual geophyte Oxalis pes‐caprae in coastal dunes, shrublands and oldfields in more than 200 sites across six Mediterranean Basin islands differing in climatic conditions and local species richness. Establishment success (i.e. percentage of plots with at least one seedling) and rates (i.e. seedling to sown seed ratio) were low, especially for Ailanthus even when accounting for differences in seed viability. Oxalis was capable of producing a new cohort of seedlings the year following planting. By contrast, all Ailanthus seedlings and half the Carpobrotus seedlings died following the first summer. Differences in establishment success and rates among ecosystems were species‐, island‐ and year‐dependent. Differences in precipitation and mean temperature were associated with differences in establishment rates across sites. Establishment rates tended to be positively correlated with cumulative precipitation and negatively with mean T^a. Unexpectedly, native species richness was not a good predictor of seedling establishment, except for higher Oxalis establishment success in species rich habitats. By conducting field sowing tests at multiple sites across a region we found that except for Oxalis, Mediterranean island ecosystems are quite resistant to invader establishment. These results suggest that differences in the degree of invasion between ecosystems and islands might be more dependent upon the influence of invasion event factors (e.g. propagule pressure) or factors acting at a later life‐history stages rather than differences in the resistance imposed by ecosystems to invader recruitment. Moreover, our results support the notion that in Mediterranean ecosystems invasions are highly idiosyncratic events and strongly dependent on water availability conditions.     

Emergence of the Introduced Grass Agropyron cristatum and the Native Grass Bouteloua gracilis in a Mixed-grass Prairie Restoration

Abstract Prairie restoration at the northern edge of the Great Plains can be frustrated by previously established non‐native perennial grasses. We compared the emergence of a widely introduced grass, Agropyron cristatum, and a common native grass, Bouteloua gracilis, in a 4‐year‐old field experiment in which the Agropyron‐dominated vegetation had either been left intact or treated annually with herbicide. This was done at two levels of water supply, reflecting conditions expected in wet and dry years, to examine the effects of among‐year variability in precipitation. Water addition significantly increased the emergence of both surface‐sown and buried (1 cm deep) seeds. Herbicide treatment of neighbors did not increase the emergence of experimentally added seeds. Emergence was much greater for buried (80%) than surface‐sown seeds (20%). Significantly more Bouteloua than Agropyron germinated from experimentally buried seeds. Whereas only a single seedling of Bouteloua emerged from the existing seed bank, the mean density of Agropyron seedlings emerging from the seed bank was 930/m² (range, 0 to 6,455/m²). Surprisingly, the emergence of Agropyron from the seed bank was not decreased by 4 years of herbicide treatment, possibly because herbicide may release Agropyron from intraspecific competition and allow increased seed production to compensate for decreased plant abundance. In summary, we found few differences between Agropyron and Bouteloua in spring and summer emergence at high or low water availability. The persistence of Agropyron stands despite repeated herbicide application may be partly due to increased seed production.     

Biotic interactions limit species richness in an alpine plant community,especially under experimental warming

The determinants of local species richness in plant communities have been the subject of much debate. Is species richness the result of stochastic events such as dispersal processes, or do local environmental filters sort species into communities according to their ecological niches? Recent studies suggest that these two processes simultaneously limit species richness, although their relative importance may vary in space and time. Understanding the limiting factors for species richness is especially important in light of the ongoing global warming, as new species establish in resident plant communities as a result of climate‐driven migration. We examined the relative importance of dispersal and environmental filtering during seedling recruitment and plant establishment in an alpine plant community subjected to seed addition and long‐term experimental warming. Seed addition increased species richness during the seedling recruitment stage, but this initial increase was cancelled out by a corresponding decrease in species richness during plant establishment, suggesting that environmental filters limit local species richness in the long term. While initial recruitment success of the sown species was related to both abiotic and biotic factors, long‐term establishment was controlled mainly by biotic factors, indicating an increase in the relative importance of biotic interactions once plants have germinated in a microhabitat with favourable abiotic conditions. The relative importance of biotic interactions also seemed to increase with experimental warming, suggesting that increased competition within the resident vegetation may decrease community invasibility as the climate warms.     

Spatial concordance at a regional scale in the regeneration process of a circum-Mediterranean relict (Buxus balearica): connecting seed dispersal to seedling establishment

Both microhabitat and temporal scales have significant effects on the regeneration process of plant species. However, the consistency of those patterns at large scales is largely unknown, despite of being essential from both an ecological and a conservation viewpoint. In this study, we examined the spatio‐temporal variation in the process of regeneration through seeds of the relict Mediterranean shrub Buxus balearica. By means of observations and experiments, we quantified the losses at different recruitment phases (seed rain, seed predation, seedling emergence and establishment) both at a small spatial scale (distance and microhabitat effects) and at a temporal scale (four years), and compared them at a regional scale (10 different localities). We additionally studied transition probabilities between phases in two populations and measured the size structure of 18 localities encompassing all the distributional range of the species. The results show that seed shadow follows a leptokurtic pattern which is consistently maintained until the seedling phase (i.e. there is spatial concordance). Despite post‐dispersal factors are spatially uncoupled, they do not remove the gradient established in the seed shadow. Although the importance of different seed predators varied between regions, post‐dispersal seed predation (ca 80%), together with seedling emergence (usually lower than 10%, some years even nil), and seedling mortality during the first summer (ca 70%) were – consistently in all populations – the most critical bottlenecks in the regeneration of the species. Moreover, an absence of seed bank prevents the buffering of dramatic losses during such phases. Watering of sown seeds increased seedling emergence and survival, and number of leaves per seedling, and survival was consistently higher under vegetation coverage. These results suggest that hydric stress notably contributes to limit the regeneration of this once widespread species evolved under a subtropical climate, which nowadays appears in old‐structured populations throughout its distributional area.     

Waterproofing Topsoil Stockpiles Minimizes Viability Decline in the Soil Seed Bank in an Arid Environment

Topsoil is a valuable resource for revegetation of mine sites as it contains seeds of plant species indigenous to the local environment. As mine site restoration is undertaken after the completion of mining, it is a common practice to stockpile topsoil in preparation for restoration activities. While many studies have found a decrease in seedling emergence with increasing stockpile age in temperate regions around the world, a few examine the effect of stockpile age on topsoil seed bank and seedling recruitment in arid environments. Seed longevity is promoted under dry conditions whereas viability loss is increased under warm and moist conditions. Here in a study in Australia's Great Sandy Desert, the effect of topsoil storage age and method of storing topsoil (under‐cover and exposed) on seedling recruitment was examined for a major gold mining site. There was a trend for lower seedling emergence (68% lower) and species richness (30% lower) from topsoil stored for 2 years than from topsoil direct returned and topsoil stored for 1 year. Seedling emergence from topsoil stockpiled for 2 years was more than 3.5‐fold higher from covered topsoil stockpiles than uncovered topsoil stockpiles. For two ecologically dominant species, after 2 years of storage, seedling emergence of the grass Triodia basedowii was 13% of direct returned topsoil and seedling emergence of the shrub Acacia stellaticeps was 68% of direct returned topsoil. The implication of the decline in seedling emergence from topsoil stockpiling on mine site revegetation in a biodiverse arid region is discussed.     

Can Establishment Characteristics Explain the Poor Colonization Success of Late Successional Grassland Species on Ex‐Arable Land?

Abstract Many grassland restoration projects on former arable land face problems because early successional grassland species establish vigorously and persistently but late successional grassland species fail to establish. Differences in establishment characteristics of early and late successional species might provide an explanation for the failure of many late successional species to colonize grasslands on ex‐arable land. I examined whether early and late successional species had different establishment rates in the initial years of a grassland succession, whether a specific establishment stage (seedling emergence, mortality or growth) could be identified as the key process controlling establishment, and what management would enhance the establishment of late successional grassland species. Seeds of three early and three late successional species were sown separately in ex‐arable plots with bare soil, 1‐year‐old vegetation, and 2‐year‐old vegetation. Emergence, mortality, and seedling growth were monitored for 1 year. Early successional species established successfully in the bare soil plots but failed to establish in plots with 1‐ and 2‐year‐old vegetation. Late successional species showed either lower establishment rates in the younger succession stages or decreased establishment with succession that nevertheless resulted in significant establishment in the oldest plots. Seedling emergence proved to be the key factor determining the establishment pattern of early and late successional species. In absolute numbers, emergence of late successional species was, however, similar or higher than that of early successional species, even in the earliest succession stage. The poor establishment of late successional species on former arable land could therefore not be explained solely by differences in establishment characteristics between early and late successional grassland species. Competitive processes between early and late successional species later in the life cycle probably play an important role. The results do point out that establishment of late successional species can be promoted by creating vegetative cover from the start of the restoration effort.     

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.     

Spatial and temporal variability in propagule limitation of California native grasses

Community composition and diversity arise from limitations in propagule supply (i.e. propagule or seed limitation) and propagule establishment after arriving at a site (i.e. establishment or microsite limitation). Recent meta‐analyses suggest that the degree of propagule limitation depends on local abiotic and biotic conditions, which in turn are likely to vary spatially and temporally. Nevertheless, seed addition studies testing propagule limitation are rarely replicated in multiple locations and years and often lack experimental manipulations of critical determinants of propagule limitation, such as the density and species richness of the propagule pool and disturbance and resource supply of recipient site. The invasion of California (USA) grasslands by exotic annual species from the Mediterranean region is unique in its scope (over 9 million ha) and persistence (more than 150 years). This invasion provides an exciting context in which to test the role of spatial and temporal variability in mediating propagule limitation and ultimately the potential for restoration. Here I present the results of native‐grass, seed‐addition trials conducted along a 500 km gradient in California in three consecutive years spanning a wide range of environmental conditions and initial conditions (e.g. rainfall, seeding density and disturbance). While native grasses were able to establish at many locations, per capita seed survival was low suggesting that the fate of these species is governed by interplay between propagule and establishment limitation. Establishment primarily varied spatially, with the most successful establishment occurring at fertile locations with low resident species richness. While recruitment was highly variable among years initially, there was no difference among seedling trials after three years.     

Effect of Sowing Season,Plant Cover,and Climatic Variability on Seedling Emergence and Survival in Burned Austrocedrus chilensis Forests

Fire is the most important disturbance factor in Cypress (Austrocedrus chilensis) forests in Patagonia, Argentina. This ecosystem recovers poorly after fire, and direct sowing could be a potentially useful restoration practice. To evaluate the effect of season of sowing, post‐fire plant cover (PC), and climatic variability on seedling emergence and survival, three direct sowing studies were established in two burned cypress stands: Trevelin (xeric conditions) and El Bolsón (mesic conditions). Two studies were conducted in winter (2000 and 2001) and one in spring (2001). Precipitation was higher than the mean during the 2000–2001 growing season and lower during 2001–2002. At both sites, emergence and survival were much higher for winter‐ than for spring‐sown seedlings. In the xeric stand, emergence and survival of winter‐sown seedlings increased with medium and high PC values, after the humid and dry summers, respectively. However, most spring‐sown seedlings did not emerge, and those that did were short‐lived. Because of the more favorable growing conditions in the mesic stand, PC had no effect on emergence and only favored first year survival of winter‐sown seedlings after the dry summer. Spring‐sown seedlings showed no association with PC in the mesic site, probably because the first summer was exceptionally humid. We speculate that shading plants exert a positive effect on cypress seedling establishment, likely by reducing the stress from high temperatures and low water availability. Sowing of small patches under the protection of understory vegetation could be useful in restoring burned cypress stands.     

Restoring Western (Basalt) Plains grassland. 2. Field emergence, establishment and recruitment following direct seeding

Summary   Both reservation of small remnants and ecological restoration of degraded areas will be crucial if the Victorian Western (Basalt) Plains grassland community is to be conserved in the long term. This study examined the potential of direct seeding as a technique for grassland restoration by recording the initial establishment and subsequent recruitment success of 64 (predominantly perennial) grassland species direct sown onto a constructed site. Forty-three (67%) of the sown species emerged and established during the 2-year study and a further three species were recorded in subsequent years. In the second year, 32 species increased their number either through seedling or vegetative recruitment and 30 species dispersed beyond their original sown plot. Seed size was not correlated with field emergence but life form did influence initial field success for some groups. The finding that many species are able to establish and recruit under the study conditions supports the need for further investigation of direct seeding in the restoration of grassland communities.     

Is broad-scale smoke–water application always a useful tool for improving seedling emergence in post-mining restoration? Evidence from jarrah forest restoration in Western Australia

It has been widely advocated that smoke–water application to topsoil can substantially improve restoration success by enhancing seed germination. This is despite few studies having tested the effects of smoke–water on seedling emergence in field-scale restoration trials. Here we report the effects of applying a commercially available smoke solution (Regen 2000®), at rates between 0 and 100 mL m^− 2, on jarrah forest sites being restored after bauxite mining in the southwest of Western Australia. Smoke solutions stimulated the seed germination of a range of species in laboratory experiments. In addition, smoke–water stimulated germination of Stylidium affine seeds sown directly into the first field experiment. However, apart from the effect on sown S. affine seeds, smoke–water application had no effect on subsequent seedling numbers, species richness or the relative proportion of seedlings in different growth-form categories in either of the two field experiments. These findings suggest that smoke–water application does not always ensure enhanced restoration outcomes.     

The influence of seed addition and cutting regime on the success of grassland restoration on former arable land

Questions: Can seed addition enhance the success of establishing species‐rich grassland on former arable land? Are sowing date and cutting regime important in determining success? Location: Aberdeen and Elgin, northeast Scotland, United Kingdom. Methods: A field experiment was conducted at two sites to assess the effect of seed addition, sowing date and cutting regime on the vegetation developing on former arable land, the aim being to compare the success of different treatments at producing a species‐rich grassland. Results: Sowing a seed mix resulted in the establishment of vegetation very distinct from the species‐poor vegetation dominated by perennial grasses which otherwise developed, though establishment success of the sown grassland species was highly variable between sites. Where establishment of the sown species was poor, sowing date had no significant effect on species composition, whereas the cutting regime was very important. Cutting the vegetation significantly increased both the number and abundance of sown species compared with the uncut control. Conversely, where establishment had been good, the cutting regime in the first year had little effect on species composition. Cutting the vegetation at least twice a year appeared to be the most effective management over the length of the experiment. Conclusions: Sowing a seed mixture significantly reduced the abundance and number of naturally colonising species, effectively controlling problem weed species such as Senecio jacobaea and Cirsium vulgare, highlighting the agronomic value of sowing seed mixtures on fallow farmland. The sowing of a seed mix on former arable land has demonstrated that it is feasible to create vegetation similar in character to that of species‐rich grasslands.     

Effects of Species Richness on Resident and Target Species Components in a Prairie Restoration

The ecological role of biodiversity in achieving successful restoration has been little explored in restoration ecology. We tested the prediction that we are more likely to create persistent, species‐rich plant communities by increasing the number of species sown, and, to some degree, by varying functional group representation, in experimental prairie plantings. There were 12 treatments consisting of 1‐, 2‐, 3‐, 4‐, 8‐, 12‐, and 16‐species mixtures of native perennials representing four functional groups (C₄ grasses, C₃ grasses, nitrogen‐fixing species, and late‐flowering composites) that predominate within Central Plains tallgrass prairies. In 2000, species were seeded into square plots (6 × 6 m), with five replicates per treatment, on former agricultural land. Annually, we measured total species richness and evenness, target species richness and cover, and richness and cover of resident species (i.e., those emerging from the seed bank). Both target species richness and rate of establishment of target communities were highest in the most species‐rich mixtures, but there was no additional benefit for treatments that contained more than eight species. Richness of resident species did not vary with target species richness; however, cover by resident species was lower in the higher target species treatments. Our results, indicating that establishment of species‐rich prairie mimics can be enhanced by starting with larger numbers of species at the outset, have implications for grassland restoration in which community biodiversity creation and maintenance are key goals.     

ECOLOGICAL CONSTRAINTS TO SEEDLING ESTABLISHMENT ON THE PUMICE PLAINS,MOUNT ST. HELENS,WASHINGTON

For both Epilobium angustifolium and Anaphalis margaritacea, the two dominant species in primary succession on the Pumice Plains on Mount St. Helens, density of the seed rain far exceeds the density of colonists. To test the hypothesis that colonization rate is limited by processes occurring during seedling establishment, we investigated the effects of subsurface moisture (using a wet and a dry site), microtopography (fine and coarse pumice particles), and seed size (five size classes), and monitored the fates of seedlings originating from experimentally sown seed for 2 years. Subsurface moisture had the strongest effect on seedling emergence and survival. By the second year there were over 20 times as many seedlings in the wet site as in the dry site; survival in the latter site was nearly zero. Coarse pumice plots had greater establishment than did fine pumice plots. Emergence rate increased significantly with increasing seed size, but this initial difference disappeared by the second year. A. margaritacea established under a wider range of conditions than did E. angustifolium. We conclude that colonization by these species, and hence rate of primary succession, is limited by availability of safe sites for germination and establishment and not by seed dispersal. Safe sites are defined primarily by the level of subsurface moisture and secondarily by microtopography and seed size, and have a greater effect on seedling emergence than on seedling survival.     

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.     

Spatio-Temporal Variation in Contrasting Effects of Resident Vegetation on Establishment,Growth and Reproduction of Dry Grassland Plants: Implications for Seed Addition Experiments

Successful establishment of plants is limited by both biotic and abiotic conditions and their interactions. Seedling establishment is also used as a direct measure of habitat suitability, but transient changes in vegetation might provide windows of opportunity allowing plant species to colonize sites which otherwise appear unsuitable. We aimed to study spatio-temporal variability in the effects of resident vegetation on establishment, growth and reproduction of dry grassland species in abandoned arable fields representing potentially suitable habitats. Seeds were sown in disturbed (bare of vegetation and roots) and undisturbed plots in three fields abandoned in the last 20 years. To assess the effects of temporal variation on plant establishment, we initiated our experiments in two years (2007 and 2008). Seventeen out of the 35 sown species flowered within two years after sowing, while three species completely failed to become established. The vegetation in the undisturbed plots facilitated seedling establishment only in the year with low spring precipitation, and the effect did not hold for all species. In contrast, growth and flowering rate were consistently much greater in the disturbed plots, but the effect size differed between the fields and years of sowing. We show that colonization is more successful when site opening by disturbance coincide with other suitable conditions such as weather or soil characteristics. Seasonal variability involved in our study emphasizes the necessity of temporal replication of sowing experiments. Studies assessing habitat suitability by seed sowing should either involve both vegetation removal treatments and untreated plots or follow the gradient of vegetation cover. We strongly recommend following the numbers of established individuals, their sizes and reproductive success when assessing habitat suitability by seed sowing since one can gain completely different results in different phases of plant life cycle.     

Can spatial variation and inter-annual variation in precipitation explain the seed density and species richness of the germinable soil seed bank in a tropical dry forest in north-eastern Brazil?

The interaction between microhabitat and inter-annual variation in precipitation has an important role on the dynamics of the seed bank and can play a crucial role in survival and maintenance of plant populations in semi-arid environments. We hypothesized that the type of microhabitat and the inter-annual variability in precipitation can explain the richness and density of the seed bank in a semi-arid region in Brazil. The study was conducted in an area of tropical dry forest with shrub-tree physiognomy, locally called caatinga. We collected 35 soil samples in three distinct microhabitats, at the end of rainy and dry seasons, respectively, over three years, totalling 630 samples. The seed bank (richness and seed density) were determined by seedling emergence method. Over the three years, 79 species emerged from the seed bank, 64, 45 and 42 in riparian, non-riparian and rocky microhabitats, respectively. We recorded differences in species richness and average density between microhabitats and between years, with significant statistical interaction between them. Inter-annual precipitation explained 48% and 5% of the variation in richness and seed density, respectively. Spatial variation explained 7% of the species richness and 31% of the density. Our results show that the interaction between spatial variation and precipitation has an important role on the spatial and temporal heterogeneity of the richness and density of seed banks in dry environments.     

Influence of litter and weather on seedling recruitment in a mixed oak-pine woodland

The effects of regular litter removal and annual variation in temperature and precipitation on seedling recruitment of species differing in their seed size and mode of dispersal were studied in a 16-year (1984-1999) experiment in a mixed oak-pine wood in southern Poland. Litter was the most important factor in determining spatial variability in seedling recruitment, whereas differences in climatic conditions among years, especially temperature fluctuations in late winter and early spring, determined the temporal variability in seedling recruitment. Compared with control plots, significantly more new individuals of bryophytes and seedlings as well as a number of new species of vascular plants were noted in the litter-removal plots over the 16-year study. Litter strongly impeded seedling emergence of small-seeded species. The negative effect of litter on seedling recruitment of large-seeded species and the recruitment of new shoots in species growing clonally was much weaker. There was a significant positive correlation between the numbers of seedlings in the litter-removal and control plots and temperatures in January to March. In the litter-removal plots this mainly affected small-seeded species. Seedling recruitment was less consistently related to variation in precipitation. Positive relationships were found only between the number of seedlings of large-seeded species in the litter-removal plots and precipitation in July of the current year and in September of the previous year, and between the number of seedlings in the control plots and precipitation in September and November of the previous year.     

Seed mix design and first year management influence multifunctionality and cost‐effectiveness in prairie reconstruction

Agricultural intensification continues to diminish many ecosystem services in the North American Corn Belt. Conservation programs may be able to combat these losses more efficiently by developing initiatives that attempt to balance multiple ecological benefits. In this study, we examine how seed mix design and first year management influence three ecosystem services commonly provided by tallgrass prairie reconstructions (erosion control, weed resistance, and pollinator resources). We established research plots with three seed mixes, with and without first year mowing. The grass‐dominated “Economy” mix had 21 species and a 3:1 grass‐to‐forb seeding ratio. The forb‐dominated “Pollinator” mix had 38 species and a 1:3 grass‐to‐forb seeding ratio. The grass:forb balanced “Diversity” mix, which was designed to resemble regional prairie remnants, had 71 species and a 1:1 grass‐to‐forb ratio. To assess ecosystem services, we measured native stem density, cover, inflorescence production, and floral richness from 2015 to 2018. The Economy mix had high native cover and stem density, but produced few inflorescences and had low floral richness. The Pollinator mix had high inflorescence production and floral richness, but also had high bare ground and weed cover. The Diversity mix had high inflorescence production and floral richness (comparable to the Pollinator mix) and high native cover and stem density (comparable to the Economy mix). First year mowing accelerated native plant establishment and inflorescence production, enhancing the provisioning of ecosystem services during the early stages of a reconstruction. Our results indicate that prairie reconstructions with thoughtfully designed seed mixes can effectively address multiple conservation challenges.