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In degraded landscapes, recolonization by pioneer vegetation is often halted by the presence of persistent environmental stress. When natural expansion does occur, it is commonly due to the momentary alleviation of a key environmental variable previously limiting new growth. Thus, studying the circumstances in which expansion occurs can inspire new restoration techniques, wherein vegetation establishment is provoked by emulating natural events through artificial means. Using the salt-marsh pioneer zone on tidal flats as a biogeomorphic model system, we explore how locally raised sediment bed forms, which are the result of natural (bio)geomorphic processes, enhance seedling establishment in an observational study. We then conduct a manipulative experiment designed to emulate these facilitative conditions in order to enable establishment on an uncolonized tidal flat. Here, we attempt to generate raised growth-promoting sediment bed forms using porous artificial structures. Flume experiments demonstrate how these structures produce a sheltered hydrodynamic environment in which suspended sediment and seeds preferentially settle. The application of these structures in the field led to the formation of stable, raised sediment platforms and the spontaneous recruitment of salt-marsh pioneers in the following growing season. These recruits were composed primarily of the annual pioneering Salicornia genus, with densities of up to 140 individuals/m² within the structures, a 60-fold increase over ambient densities. Lower abundances of five other perennial species were found within structures that did not appear elsewhere in the pioneer zone. Furthermore, recruits grew to be on average three times greater in mass inside of the structures than in the neighboring ambient environment. The success of this restoration design may be attributed to the combination of three factors: (1) enhanced seed retention, (2) suppressed mortality, and (3) accelerated growth rates on the elevated surfaces generated by the artificial structures. We argue that restoration approaches similar to the one shown here, wherein the conditions for natural establishment are actively mimicked to promote vegetation development, may serve as promising tools in many biogeomorphic ecosystems, ranging from coastal to arid ecosystems.

Saatkamp, A., Cochrane, A., Commander, L., Guja, L., Jimenez-Alfaro, B., Larson, J., Nicotra, A., Poschlod, P., Silveira, F.A.O., Cross, A., Dalziell, E.L., Dickie, J., Erickson, T.E., Fidelis, A., Fuchs, A., Golos, P.J., Hope, M., Lewandrowski, W., Merritt, D.J., Miller, B.P., Miller, R., Offord, C.A., Ooi, M.K.J., Satyanti, A., Sommerville, K.D., Tangney, R., Tomlinson, S., Turner, S., Walck, J.L.

The vibrant Irish public house of the nineteenth century hosted broad networks of social power, enabling publicans and patrons to disseminate tremendous influence across Ireland and beyond. During the period, affluent publicans coalesced into one of the most powerful and sophisticated forces in Irish parliamentary politics. Among the leading figures of public life, they commanded an unmatched economic route to middle-class prosperity, inserted themselves into the centre of crucial legislative debates, and took part in fomenting the issues of class, gender, and national identity which continue to be contested today. From the other side of the bar, regular patrons relied on this social institution to construct, manage and spread their various social and political causes. From Daniel O'Connell to the Guinness dynasty, from the Acts of Union to the Great Famine, and from Christmas boxes to Fenianism; Bradley Kadel offers a first and much-needed scholarly examination of the ‘incendiary politics of the pub’ in nineteenth-century Ireland.

Manipulating plant roots before installation is commonly employed to support establishment and vigorous growth of ornamental plants in the landscape; however, different methods and species-specific responses require more investigation. This study compared three pre-planting practices (slicing, hand-teasing, or severing the root ball) vs. no root manipulation in the establishment of Lagerstroemia ‘Natchez’, one of the most common trees in the southern landscape. Plant growth index (height/widths), stem caliper, and end-of-study biomass were assessed. No differences between treatments were observed throughout or at the termination of the study, suggesting vigorously growing plants like Lagerstroemia may be less dependent on pre-plant root manipulation for successful establishment and that these practices may neither inhibit or enhance plant vigor. Our results indicate that if provided modest care, Lagerstroemia are a robust ornamental taxon that can be successfully established regardless of pre-plant root modifications; however, long-term benefits of root-manipulation practices may still be realized.

The application of biostimulants from natural origin represents one of the most innovative and promising strategies to promote plant growth and improve crop productivity. The biostimulants have the potential to release dormancy and enhance seed germination of many plant species by altering the physiological processes in seeds even under abiotic stress. The seed application of biostimulants has been considered as a simple, beneficial and sustainable technique to enhance crop productivity. An understanding of non-microbial biostimulants-induced seed germination, dormancy release and seedling establishment mechanisms may help to improve crop productivity. However, the impending mechanisms involved in the regulation of seed germination and seedling establishment by non-microbial biostimulants are still elusive. In this review, the possible mode of action of various non-microbial biostimulants in seed germination and the seedling establishment under optimal and sub-optimal conditions has been discussed. Furthermore, the gaps in utilizing the full potential of these biostimulants are also addressed.

Establishment and persistence are central to community assembly and are determined by how traits interact with the environment to determine performance (trait–environment interactions). Community assembly studies have rarely considered such trait–environment interactions, however, which can lead to incorrect inferences about how traits affect assembly. We evaluated how functional traits, environmental conditions, and trait–environment interactions structure plant establishment, as a measure of performance. Within 12 prairie restorations created by sowing 70 species, we quantified environmental conditions and counted individuals of each seeded species to quantify first-year establishment. Three trait–environment interactions structured establishment. Leaf nitrogen interacted with herbivore pressure, as low leaf nitrogen species established relatively better under higher herbivory than species with high leaf nitrogen. Soil moisture interacted with root mass fraction (RMF), with low-RMF species establishing better with low soil moisture and higher-RMF species better on wetter soils. Specific leaf area (SLA) interacted with light availability, as low-SLA species established better under high light conditions and high-SLA species under low light conditions. Our work illustrates how community assembly can be better described by trait–environment interactions than correlating traits or environment with performance. This knowledge can assist species selection to maximize restoration success.

Soybean seeds contain higher concentrations of oil (triacylglycerol) and fatty acids than do cereal crop seeds, and the oxidation of these biomolecules during seed storage significantly shortens seed longevity and decreases germination ability. Here, we report that diethyl aminoethyl hexanoate (DA-6), a plant growth regulator, increases germination and seedling establishment from aged soybean seeds by increasing fatty acid metabolism and glycometabolism. Phenotypic analysis showed that DA-6 treatment markedly promoted germination and seedling establishment from naturally and artificially aged soybean seeds. Further analysis revealed that DA-6 increased the concentrations of soluble sugars during imbibition of aged soybean seeds. Consistently, the concentrations of several different fatty acids in DA-6-treated aged seeds were higher than those in untreated aged seeds. Subsequently, quantitative PCR analysis indicated that DA-6 induced the transcription of several key genes involved in the hydrolysis of triacylglycerol to sugars in aged soybean seeds. Furthermore, the activity of invertase in aged seeds, which catalyzes the hydrolysis of sucrose to form fructose and glucose, increased following DA-6 treatment. Taken together, DA-6 promotes germination and seedling establishment from aged soybean seeds by enhancing the hydrolysis of triacylglycerol and the conversion of fatty acids to sugars.

Seeds are central to crop production, human nutrition, and food security. A key component of the performance of crop seeds is the complex trait of seed vigour. Crop yield and resource use efficiency depend on successful plant establishment in the field, and it is the vigour of seeds that defines their ability to germinate and establish seedlings rapidly, uniformly, and robustly across diverse environmental conditions. Improving vigour to enhance the critical and yield-defining stage of crop establishment remains a primary objective of the agricultural industry and the seed/breeding companies that support it. Our knowledge of the regulation of seed germination has developed greatly in recent times, yet understanding of the basis of variation in vigour and therefore seed performance during the establishment of crops remains limited. Here we consider seed vigour at an ecophysiological, molecular, and biomechanical level. We discuss how some seed characteristics that serve as adaptive responses to the natural environment are not suitable for agriculture. Past domestication has provided incremental improvements, but further actively directed change is required to produce seeds with the characteristics required both now and in the future. We discuss ways in which basic plant science could be applied to enhance seed performance in crop production.

Climate warming is contributing to increases in wildfire activity throughout the western United States, leading to potentially long-lasting shifts in vegetation. The response of forest ecosystems to wildfire is thus a crucial indicator of future vegetation trajectories, and these responses are contingent upon factors such as seed availability, interannual climate variability, average climate, and other components of the physical environment. To better understand variation in resilience to wildfire across vulnerable dry forests, we surveyed conifer seedling densities in 15 recent (1988–2010) wildfires and characterized temporal variation in seed cone production and seedling establishment. We then predicted postfire seedling densities at a 30-m resolution within each fire perimeter using downscaled climate data, monthly water balance models, and maps of surviving forest cover. Widespread ponderosa pine (Pinus ponderosa) seed cone production occurred at least twice following each fire surveyed, and pulses of conifer seedling establishment coincided with years of above-average moisture availability. Ponderosa pine and Douglas-fir (Pseudotsuga menziesii) seedling densities were higher on more mesic sites and adjacent to surviving trees, though there were also important interspecific differences, likely attributable to drought and shade tolerance. We estimated that postfire seedling densities in 42% (for ponderosa pine) and 69% (for Douglas-fir) of the total burned area were below the lowest reported historical tree densities in these forests. Spatial models demonstrated that an absence of mature conifers (particularly in the interior of large, high-severity patches) limited seedling densities in many areas, but 30-yr average actual evapotranspiration and climatic water deficit limited densities on marginal sites. A better understanding of the limitations to postfire forest recovery will refine models of vegetation dynamics and will help to improve strategies of adaptation to a warming climate and shifting fire activity.

Robust tree regeneration following high-severity wildfire is key to the resilience of subalpine and boreal forests, and 21st century climate could initiate abrupt change in forests if postfire temperature and soil moisture become less suitable for tree seedling establishment. Using two widespread conifer species, lodgepole pine (Pinus contorta var. latifolia) and Douglas-fir (Pseudotsuga menziesii var. glauca), we conducted complementary experiments to ask (1) How will projected early-to mid-21st-century warming and drying affect postfire tree seedling establishment and mortality? (2) How does early seedling growth differ between species and vary with warming and drying? With a four-year in situ seed-planting experiment and a one growing season controlled-environment experiment, we explored effects of climate on tree seedling establishment, growth, and survival and identified nonlinear responses to temperature and soil moisture. In our field experiment, warmer and drier conditions, consistent with mid-21ˢᵗ-century projections, led to a 92% and 76% reduction in establishment of lodgepole pine and Douglas-fir. Within three years, all seedlings that established under warmer conditions died, as might be expected at lower elevations and lower latitudes of species' ranges. Seedling establishment and mortality also varied with aspect; approximately 1.7 times more seedlings established on mesic vs. xeric aspects, and fewer seedlings died. In the controlled-environment experiment, soil temperatures were 2.0°–5.5°C cooler than the field experiment, and warming led to increased tree seedling establishment, as might be expected at upper treeline or higher latitudes. Lodgepole pine grew taller than Douglas-fir and produced more needles with warming. Douglas-fir grew longer roots relative to shoots, compared with lodgepole pine, particularly in dry soils. Differences in early growth between species may mediate climate change effects on competitive interactions, successional trajectories, and species distributions. This study demonstrates that climate following high-severity fire exerts strong control over postfire tree regeneration in subalpine conifer forests. Climate change experiments, such as those reported here, hold great potential for identifying mechanisms that could underpin fundamental ecological change in 21st-century ecosystems.