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1
Duchesneau, Robin, and Hubert Morin. "Early seedling demography in balsam fir seedling banks." Canadian Journal of Forest Research 29, no. 10 (1999): 1502–9. http://dx.doi.org/10.1139/x99-090.
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Following the 1995 mast year, we conducted detailed seedling demography surveys to characterize some ecological factors affecting germination and early establishment in understory balsam fir (Abies balsamea (L.) Mill.) seedling banks and verify if recruitment from a cohort can potentially renew the balsam fir seedling bank. Twenty-five seed traps paired with 32 demography subplots were located in each of four permanent plots and regularly monitored over a 2-year period. Spatial patterns of newly emerged seedlings generally corresponded to those found for seed dispersal. However, at the end of the monitoring period, the spatial pattern of surviving seedlings was independent of the seed dispersal pattern. Seedbed types and understory light environments were the main factors explaining seedling mortality. Sphagnum mosses and decaying wood were the most favorable seedbeds for early establishment. The 0- to 25-cm seedling populations grew in size because of the addition of new recruits. If, in the years to come, mortality rates of the 1995 cohorts were similar to those of already established 0- to 25-cm seedlings, mast years of seed production, at least during endemic periods, would be crucial for recruitment and renewal of balsam fir seedling banks.
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Morgan, P., and L. F. Neuenschwander. "Seed-bank contributions to regeneration of shrub species after clear-cutting and burning." Canadian Journal of Botany 66, no. 1 (1988): 169–72. http://dx.doi.org/10.1139/b88-026.
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Seed banks contributed significantly to regeneration of early seral shrubs after clear-cutting and fall broadcast burning of dense coniferous forests of the Thuja plicata/Clintonia uniflora habitat type in northern Idaho. Seeds were separated from 36 samples of soil and surface organic matter from 15 uncut forest stands. Total seed density averaged 1151 ± 1896 seeds/m2, and seed density for individual shrub species ranged from 1 ± 3 to 690 ± 1728 seeds/m2. Canopy cover of the "obligate" seed bank species, such as Ceanothus sanguineus and Prunus emarginata, was low or nonexistent in uncut forests, seed constancy and density in seed bank were high, and seedling regeneration on 2-year-old burns was abundant. Species that were "non-reliant" on seed banks, including Symphoricarpos albus and Rosa gymnocarpa, resprouted and no seedlings were found after burning. Response of "opportunistic" seed-bank species such as Rubus parviflorus and Rubus ursinus was intermediate; both seedling and sprout regeneration occurred after cutting and burning. These species existed in uncut stands both in the seed bank and in the understory. Burn severity affected germination and (or) seedling survival of Ceanothus sanguineus. Its percent canopy cover was greater on high-severity than on low-severity 2-year-old burns.
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Leon, Ramon G., and Micheal D. K. Owen. "Artificial and natural seed banks differ in seedling emergence patterns." Weed Science 52, no. 4 (2004): 531–37. http://dx.doi.org/10.1614/ws-03-048r2.
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Artificial weed seed banks are practical for studying seed bank depletion and weed seedling emergence because the number, depth, and species composition of seed banks can be managed. However, no studies have determined whether artificial seed banks are representative of natural seed banks. We compared the emergence of velvetleaf, giant foxtail, and common waterhemp in a natural seed bank, an artificial seed bank with stratified seeds, and an artificial seed bank with nonstratified seeds. Velvetleaf seedling emergence was higher in the nonstratified seed bank in 2001, but no differences were observed in 2002. The number of viable velvetleaf seeds at the end of the experiment was lower in the natural seed bank than in the artificial seed banks in 2002. Velvetleaf emergence occurred earlier in the natural seed bank than in the artificial seed banks. Giant foxtail emergence was higher in the artificial seed banks (58 to 82%) than in the natural seed bank (5 to 23%). Common waterhemp emergence ranged from 7 to 65% in the artificial seed banks and from 1 to 5% in the natural seed bank. In general, the distribution of emergence with time differed in the natural seed bank compared with the artificial seed banks. These differences were attributed to differences in soil temperature and soil bulk density between the natural and artificial seed banks. Artificial seed banks showed lower soil bulk density and greater temperature fluctuation than the natural seed bank. However, there was no consistent relationship between growing degree days and emergence timing in the three treatments for any of the species studied.
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Vieno, M., M. Komulainen, and S. Neuvonen. "Seed bank composition in a subarctic pine–birch forest in Finnish Lapland: natural variation and the effect of simulated acid rain." Canadian Journal of Botany 71, no. 3 (1993): 379–84. http://dx.doi.org/10.1139/b93-042.
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The seed bank composition and seedling densities were determined for a subarctic pine–birch forest. Samples (12 × 12 cm) were taken from plots that had received sulphuric acid and (or) nitric acid irrigation of pH 3 for 5 years and from irrigated control plots. The average seedling density per plot calculated from seedbank samples was 912/m2, varying from 191 to 5240. All the main aboveground taxa were present in the emerging seedlings with Betula sp. and Empetrum nigrum ssp. hermaphroditum being dominant. Other common seed-bank species included Vaccinium uliginosum, Vaccinium vitis-idaea, and Festuca ovina. Acid treatment did not have any significant impact on the composition of the seed bank or on germinative capacity in general. These findings indicate the existence of a viable soil seed bank in northern subarctic forests and the persistence of viability in spite of moderate acid deposition. Key words: seed bank, simulated acid rain, subarctic forest, seedling.
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Komulainen, M., M. Vieno, V. T. Yarmishko, T. D. Daletskaja, and E. A. Maznaja. "Seedling establishment from seeds and seed banks in forests under long-term pollution stress: a potential for vegetation recovery." Canadian Journal of Botany 72, no. 2 (1994): 143–49. http://dx.doi.org/10.1139/b94-019.
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Seed germinability of some common dwarf shrubs and seed-bank composition were studied in young pine forests along a pollution gradient from Severonickel smelter in Monchegorsk, northern Russia. Samples for seed germination and seed-bank trials were taken from sites representing different zones of pollution. Generally, germinability of dwarf shrub seeds was not affected by distance from pollution source, except for Empetrum nigrum ssp. hermaphroditium. The average density per site of seedlings that emerged from seed-bank samples varied between 278 and 416 seedlings/m2. Empetrum nigrum ssp. hermaphroditum and Betula sp. dominated in seed banks. Calluna vulgaris was also numerous at one site. As a whole, seed-bank taxa were well represented in the above ground vegetation. There were no significant differences in seedling density between sites for dominant taxa. Our results indicate that seeds can retain viability even under a heavy pollution load and thus form a potential for vegetation recovery in polluted sites. Key words: seed germination, seed bank, recovery, pollution, coniferous forest.
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Peltonen-Sainio, Pirjo, Katri Pahkala, Hannu Mikkola, and Lauri Jauhiainen. "Seed loss and volunteer seedling establishment of rapeseed in the northernmost European conditions: potential for weed infestation and GM risks." Agricultural and Food Science 23, no. 4 (2014): 327–39. http://dx.doi.org/10.23986/afsci.41530.
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Rapeseed soil seed bank development and volunteer plant establishment represent substantial risk for crop infestation and GM contamination. This study was designed to complement such investigations with novel understanding from high latitude conditions. Four experiments were designed to characterise seed loss at harvest, persistence, viability and capacity for volunteer seedling establishment, as well as impact of management measures on soil seed bank dynamics. Oilseed rape was the primary crop investigated due to the availability of GM cultivars and because of the increasing importance. Harvest losses and soil seed bank development were significant. Volunteer seedlings emerged at reasonably high rates, especially in the first autumn after harvest, but about 10% of buried seeds maintained their viability for at least three years. Soil incorporation methods had no major effect on numbers of volunteer seedlings, but herbicide treatments controlled volunteer seedlings efficiently, though not completely, due to irregular timing of seedling emergence.
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Zhang, Jianhua, and Paul B. Cavers. "Seedling emergence after maternal bentazon application to 10 cocklebur (Xanthium strumarium) populations." Canadian Journal of Plant Science 74, no. 4 (1994): 863–66. http://dx.doi.org/10.4141/cjps94-157.
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Maternal environments have been reported to affect various seed and seedling characteristics in many plants. In this study, we examined the effect of bentazon application to the mother plants on seed germination and seedling emergence of 10 cocklebur populations from wetlands or cultivated land. The mortality or longevity of fully developed seeds was affected significantly by bentazon application. Rate of seedling emergence showed little response, whereas percentage seedling emergence and percentage viable seeds in the soil were reduced by bentazon treatment to the mother plants. Populations from wetlands produced seedlings earlier than those from cultivated land. Key words: Seedling emergence, seed bank, herbicide, bentazon, cocklebur, Xanthium strumarium
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Grewell, Brenda J., Morgane B. Gillard, Caryn J. Futrell, and Jesús M. Castillo. "Seedling Emergence from Seed Banks in Ludwigia hexapetala-Invaded Wetlands: Implications for Restoration." Plants 8, no. 11 (2019): 451. http://dx.doi.org/10.3390/plants8110451.
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Soil seed banks play a critical role in the maintenance of wetland plant communities and contribute to revegetation following disturbances. Analysis of the seed bank can therefore inform restoration planning and management. Emergence from seed banks may vary in response to hydrologic conditions and sediment disturbances. To assess the community-level impact of exotic Ludwigia hexapetala on soil seed banks, we compared differences in species composition of standing vegetation among invaded and non-invaded wetlands and the degree of similarity between vegetation and soil seed banks in northern California. To determine potential seed bank recruitment of L. hexapetala and associated plant species, we conducted a seedling emergence assay in response to inundation regime (drawdown vs. flooded) and sediment depth (surface vs. buried). Plant species richness, evenness, and Shannon’s H’ diversity were substantially lower in standing vegetation at L. hexapetala invaded sites as compared to non-invaded sites. Over 12 months, 69 plant taxa germinated from the seed banks, including L. hexapetala and several other exotic taxa. Seedling density varied among sites, being the highest (10,500 seedlings m−2) in surface sediments from non-invaded sites subjected to drawdown treatments. These results signal the need for invasive plant management strategies to deplete undesirable seed banks for restoration success.
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Chejara, V. K., P. Kristiansen, B. M. Sindel, R. D. B. Whalley, and C. Nadolny. "Seed-bank and seedling dynamics in Hyparrhenia hirta are influenced by herbicide application and mowing management." Rangeland Journal 34, no. 2 (2012): 199. http://dx.doi.org/10.1071/rj11057.
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Hyparrhenia hirta (L.) Stapf (Coolatai grass) is a summer-active, C4 perennial tussock grass, native to southern Africa and the Mediterranean region, which has invaded areas of native flora in Australia in recent decades. Understanding its seed and seedling dynamics and how various management treatments (e.g. mowing, herbicide and no management) affect these may assist in identifying the conditions and management strategies required to limit its invasion. The population dynamics of H. hirta have not been comprehensively studied previously. A 2-year field experiment (December 2005–December 2007) was conducted to determine the seed-bank size, pattern of seedling emergence and survival of H. hirta seedlings at three sites in northern New South Wales, Australia, under three treatments: unmanaged (control), mowing and herbicide treatments. The density of H. hirta seeds in the soil at each experimental site under different treatments was measured in December 2005 at the start of the experiment, in December 2006 before the application of the second round of treatments and again at the end of the experiment in December 2007. Hyparrhenia hirta seedlings were assessed at monthly intervals in permanent quadrats (0.5 × 0.5 m) to determine seedling emergence and survival. Seedling emergence occurred on many occasions during the 2-year period of the experiment in each treatment and at all sites but the main seedling flushes were observed from mid summer to early autumn. In 2007, at all sites, seedling emergence declined by more than 90% on the mowing and herbicide treatments compared with the control treatment. Seedling survival was greater in the mowing and herbicide treatments than in the control treatment. The seedling cohorts emerging in winter had a lower survival. This study showed that H. hirta infestations have a large viable seed-bank (~3000 m–2), dependent on the level of infestation and climatic conditions, but that the seed-bank declines rapidly when seed addition is prevented. Some form of direct control of established H. hirta plants in combination with providing appropriate grazing management to encourage competition between grasses will assist in the control of H. hirta.
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Salazar, Ana, Guillermo Goldstein, Augusto C. Franco, and Fernando Miralles-Wilhelm. "Timing of seed dispersal and dormancy, rather than persistent soil seed-banks, control seedling recruitment of woody plants in Neotropical savannas." Seed Science Research 21, no. 2 (2011): 103–16. http://dx.doi.org/10.1017/s0960258510000413.
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AbstractA large fraction of tree species forming persistent soil seed-banks and with dormant seeds are expected to be found in strongly seasonal ecosystems such as Neotropical savannas, where seedling recruitment could be highly variable. In the savannas of Central Brazil, we studied seed characteristics (type of dormancy, longevity and moisture content) of 14 representative woody species differing in seed dispersal season. We also studied the dynamics of soil seed-banks and similarity patterns in woody species composition among seed rain, soil seed-bank, seedling bank and standing vegetation along shallow topographic gradients that differ in canopy cover. Woody species composition of the soil seed-bank largely differed from the standing vegetation, the seed rain and the seedling bank species composition, suggesting low recruitment of woody species from the soil seed-bank. Seeds of the 14 woody species remained viable for less than 16 months in laboratory dry-storage conditions. Of those, most seeds dispersed in the dry season were dormant and exhibited low moisture content, while most seeds dispersed in the wet season were non-dormant and exhibited high moisture content. Longevity of these seeds dispersed in the dry and the wet seasons did not differ significantly. This study shows that both timing of seed dispersal and dormancy appear to control timing of seed germination and seedling recruitment of most Neotropical savanna woody species, which did not form persistent soil seed-banks. This study contributes to the understanding of tree/grass coexistence and tree density variations along topographic gradients in tropical savannas.
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Zamora, David L., and Donald C. Thill. "Seed Bank Longevity of Common Crupina (Crupina vulgaris) in Natural Populations." Weed Technology 3, no. 1 (1989): 166–69. http://dx.doi.org/10.1017/s0890037x00031547.
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Seedling emergence and seed bank longevity were followed in field experiments with natural populations of common crupina for 4 yr. Emergence the first fall after dissemination was 90 to 98% of all seedlings eventually to emerge from the seedbank. Seedling emergence over time did not differ between plots which either were treated with the potassium salt of picloram or were hand weeded. No viable seed remained in the soil 25 to 26 months after seed production stopped. Five locations in a common crupina infestation undergoing eradication were sampled for seed in the soil. No viable seeds were found during the first year of the eradication, and no intact seeds were found after 4 yr.
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OLALOYE, Omowumi Omotoyosi, and Samson Olajide OKE. "Soil Seed Bank Dynamics of a Riparian Forest and its Adjacent Upland Vegetation." Notulae Scientia Biologicae 8, no. 1 (2016): 118–24. http://dx.doi.org/10.15835/nsb819761.
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The present study was conducted to determine the densities and soil seed bank composition of a riparian forest and its adjacent upland vegetation for a better understanding the potentials of the soil seed banks in facilitating succession towards a more natural forest of native tree species. Three contiguous 20 m x 20 m plots were systematically established on both riparian forest and upland vegetation. Species enumeration, identification and distribution into families of the standing vegetation were carried out. Furthermore, five replicates soil samples were collected at two different depths (0-15 cm, 15-30 .The seedling emergence test was carried out for six months in the greenhouse to determine the species composition and the density of the seed in both vegetation types. The results of the seedling emergence revealed that more seeds were deposited at the upper depth (0-15 cm) than the lower depth 15-30 cm in the two vegetation types in both dry and rainy season. There was low similarity in species composition between the standing vegetation and soil seed bank in each of the two vegetation types. Herbaceous species recorded the highest number of seedlings as compared to the other habit. The low similarity between seed bank and standing vegetation of the riparian forest and the adjacent upland vegetation suggested that soil seed bank was insignificant in their restoration.
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Newediuk, Levi J., and James F. Hare. "Burrowing Richardson’s ground squirrels affect plant seedling assemblages via environmental but not seed bank changes." Current Zoology 66, no. 3 (2019): 219–26. http://dx.doi.org/10.1093/cz/zoz047.
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Abstract In grassland ecosystems, burrowing mammals create disturbances, providing habitat for animal species and increasing plant community diversity. We investigated whether seedling assemblages on Richardson’s ground squirrel Urocitellus richardsonii mounds result from seed rearrangement or environmental changes that favor germination of certain species over others. To test whether ground squirrels rearrange the seed bank by burrowing, we compared seed compositions among mounds, burrows, and undisturbed soil. To test whether ground squirrels change environmental conditions, we compared soil nitrate and bare ground cover on and off mounds. We also compared seedlings that germinated on mounds with seedlings that germinated on artificial disturbances from which we removed aboveground vegetation. Soil nitrate and bare ground cover were significantly higher on mounds than artificial disturbances. While seed richness and abundance did not differ among mounds, burrows, and undisturbed soil, seedling richness was reduced on mounds relative to artificial disturbances. Burrowing disturbance favors seedlings that can capitalize on bare ground availability but are less able to immobilize nitrate, as opposed to perennial species that immobilize more nitrate but take longer to establish. Our results suggest that Richardson’s ground squirrels act as ecosystem engineers, although future research following succession on ground squirrel mounds is necessary to understand how they influence plant communities past the seedling stage.
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Nicol, Jason, Sally Muston, Paula D'Santos, Bernard McCarthy, and Sylvia Zukowski. "Impact of sheep grazing on the soil seed bank of a managed ephemeral wetland: implications for management." Australian Journal of Botany 55, no. 2 (2007): 103. http://dx.doi.org/10.1071/bt04137.
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The seed bank is an important mechanism for the persistence of species in ephemeral wetlands, but grazing by domestic stock may change the seed bank and in turn the capacity of the system to recover from disturbance. The sediments of two areas in Thegoa Lagoon (Murray–Darling Basin), one area grazed by sheep when dry and the other ungrazed, were examined. The objective of the study was to determine whether and how the (1) germinable seed bank and (2) final plant communities differ between the grazed and ungrazed areas. The seed banks were subjected to one of the following three water depths: 5 cm above the surface of the water, 5 cm below the surface and 50 cm below the surface. The composition of the seed bank was determined by using the seedling-emergence technique for 12 weeks, with seedlings removed every 2 weeks. The final plant communities were determined at 12 weeks without removing seedlings. The seed bank from the grazed area had a significantly lower seed density (5600 ± 593 seeds m–2) and species richness (7 species) than the ungrazed area (37 683 ± 4492 seeds m–2, 16 species) (ANOVA: F1, 10 = 50.16, P < 0.0001). The floristic composition of the seed bank was also significantly different between the areas (NPMANOVA: F1, 10 = 15.44, P = 0.0032). Glinus lotoides was in higher abundance in the grazed area and Alternanthera denticulata, Persicaria lapathifolium, Polygonum plebium, Typha domingensis and Centipeda cunninghamii in the ungrazed area. Similarly, the final communities derived from the grazed and ungrazed areas were significantly different from each other (NPMANOVA: F1, 10 = 15.53, P = 0.0032). Greater numbers of Centipeda cunninghamii were present in the community from the grazed area and Alternanthera denticulata and Cuscuta campestris were present in larger numbers in the community from the ungrazed area. Water depth also had an impact on germination; no germination occurred in seed banks flooded to 50 cm and one Typha domingensis seedling was observed in a sample flooded to 5 cm. These results showed that grazing reduces the density and species richness of the seed bank and in turn changes the plant communities derived from the seed bank; however, if grazing is removed pest plants such as Cuscuta campestris may require control. In addition, managed drawdown or water-level fluctuations are important in exposing wetland sediments and allowing for species to recruit from the seed bank.
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Xu, Qing Tao, and Shou Gang Yan. "Effects of Soil Moisture on Vegetation Invasion into Active Dune Areas." Advanced Materials Research 864-867 (December 2013): 2541–44. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2541.
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Soil moisture and soil seed bank are primary dependent factors during the vegetation natural regenerations in semi-arid sand areas. But the binary correlation analysis between seedling density and soil seed bank density as well soil moisture in transition zones between the windword slope of active dune and interdune lowland indicated that the correlation between seedling density and soil seed bank density was not significant (P>0.05) in the plant growing season; but the one between seedling density and soil moisture was significant and positive (P<0.05). The conclusions revealed that soil moisture was a primary dependent factor during seedling emergence and establishment in the transition zone
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Weekley, Carl W., Eric S. Menges, and Pedro F. Quintana-Ascencio. "Seedling emergence and survival of Warea carteri (Brassicaceae), an endangered annual herb of the Florida Scrub." Canadian Journal of Botany 85, no. 7 (2007): 621–28. http://dx.doi.org/10.1139/b07-061.
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Seedling emergence and survival to flowering are critical processes in the life history of annual plants. We evaluated the importance of year and habitat on seedling emergence and the effects of year, habitat, timing of seedling emergence, and seedling density on survival of Warea carteri Small, an annual mustard endemic to Florida scrub. We tagged 1329 seedlings in 78 permanent 0.25 m2 quadrats in two habitats (scrub and disturbed) between 1999 and 2002 and followed seedlings monthly. Most (>80%) seedling emergence occurred between September and December. Emergence peaked 2 months earlier and was more variable in disturbed sites than in scrub. Seedling survival among years ranged from 3.5% to 12.0%. Seedling density varied from 1 to 75 per 0.25 m2 quadrat, with an overall median of 6.0. Survival was not density dependent. Median age at flowering ranged from 11.7 to 15.2 months, with late season recruits most likely to survive to flowering. Warea carteri recruits like a winter annual but flowers like a summer annual. Its delayed germination and a 12–15 month life span contribute to population cycling. Complete reproductive failure in unfavorable years, high seed production in favorable years, low rates of seed germination, and a persistent seed bank are consistent with predictions for an annual species in a variable habitat.
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Fumanal, B., I. Gaudot, and F. Bretagnolle. "Seed-bank dynamics in the invasive plant,Ambrosia artemisiifoliaL." Seed Science Research 18, no. 2 (2008): 101–14. http://dx.doi.org/10.1017/s0960258508974316.
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AbstractThe seed-bank dynamics ofAmbrosia artemisiifolia(Asteraceae), an annual invasive plant introduced from North America to Europe, were studied in nine French populations developing in field crops, set-asides or wastelands. The vertical distribution of seeds was studied in two different depth sections (0–5 cm and 5–20 cm), and the spatial horizontal pattern of distribution was analysed for two selected field-crop and set-aside populations. The proportions of dormant, non-dormant and dead seeds, as well as the changes in seed-bank dormancy over time, were evaluated. Natural seedling recruitment and its variation under different disturbance treatments in competitive set-asides were also studied. From 536 ± 194 to 4477 ± 717 seeds m− 2were found in the living seed bank (0–20 cm). The majority of seeds in field crops was found in the lower soil layer, whereas the opposite pattern was observed in set-asides and wastelands. Dormant seed proportions were low (0–18%) before natural germination, but then regularly increased. The seed bank ofA. artemisiifoliawas spatially aggregated irrespective of the extent of soil disturbance. On average, 23 ± 12 to 292 ± 62 seedlings m− 2were recorded, with densities lower in set-asides than in field crops and wastelands. Seedling densities were not correlated to upper seed densities except for two field crops. Soil disturbance and the removal of vegetation had positive effects on seedling recruitment in set-asides. Seed-bank dynamics appear to be crucial in the invasive success ofA. artemisiifolia, and this knowledge will provide insights for the management of the species.
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Ingersoll, Cheryl A., and Mark V. Wilson. "Buried propagule bank of a high subalpine site: microsite variation and comparisons with aboveground vegetation." Canadian Journal of Botany 71, no. 5 (1993): 712–17. http://dx.doi.org/10.1139/b93-082.
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We assessed the composition and spatial pattern of the persistent buried propagule bank (seeds and vegetative structures) of a treeline site in the Oregon Cascade Mountains. We monitored emergence from soil cores removed from four microsite types and recorded vegetation cover and seedling abundance on the site. Over 3100 seedlings/m2 emerged from the greenhouse soil cores; the seed bank was dominated by Juncus species. Few vegetative sprouts emerged. Vegetated microsites produced significantly more emergents than did bare soils, but even bare soils contained abundant seeds. Overall site cover was low and few seedlings occurred on the site. Discrepancies between aboveground and belowground abundance were common. Phyllodoce empetriformis and Luetkea pectinata were abundant in the vegetation and produced many seeds but were poorly represented in the seed bank and as seedlings on the site. Other species were abundant in the seed bank, but rare in the vegetation. Our results indicate that despite the abundance of seeds in bare soil, colonization is likely to be extremely slow. Key words: seed bank, subalpine, seedlings, microsite, spatial pattern.
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Parent, Sylvain, Marie-Josée Simard, Hubert Morin, and Christian Messier. "Establishment and dynamics of the balsam fir seedling bank in old forests of northeastern Quebec." Canadian Journal of Forest Research 33, no. 4 (2003): 597–603. http://dx.doi.org/10.1139/x02-194.
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This study examines balsam fir (Abies balsamea (L.) Mill.) recruitment in old fir stands. Studying the regeneration of these stands is essential to understand the regeneration dynamic of the species in the absence of stand-destroying disturbances. The objectives were (1) to obtain substrateseedling associations for different age-classes and according to the presence or absence of adventitious roots; (2) to evaluate the contribution of the seed rain to seedling recruitment; (3) to re-examine age structures using the most appropriate method that minimizes estimation errors due to the presence of adventitious roots. A total of 90 quadrats (1 m2) were established along transects. In each quadrat, subtrates were characterized (type and topography) and their area was estimated. All balsam fir seedlings (<50 cm tall) present in the quadrats were located, harvested whole (root and shoot), and described (age, height, presence of adventitious roots, etc). Fir seedlings were strongly associated with woody mounds covered with thin mats of mixed mosses and Pleurozium shreberi (Bird.) Mitt. but negatively associated with flat topography particularly dominated by Hylocomium splendens (Hedw.) B.S.G. The presence of adventitious root is related to seedling age more than substrate type or topography. The age structure is in agreement with seed production and disturbance regime.
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Wang, Shulin, and Fujiang Hou. "Short-term study on the yak dung seed bank on the Qinghai-Tibetan Plateau: effects of grazing season, seed characteristics and forage preferences." Plant and Soil 465, no. 1-2 (2021): 367–83. http://dx.doi.org/10.1007/s11104-021-05009-5.
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Abstract Aims Viable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), seed characteristics (size and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear. Methods We collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture. Results Forty-three plant species (mainly perennials) germinated from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small to medium-sized spherical seeds (seed size < 10 mg, shape index < 0.5) had the greatest germination potential. Conclusions Yaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and size directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.
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Brown, Doug. "Estimating the composition of a forest seed bank: a comparison of the seed extraction and seedling emergence methods." Canadian Journal of Botany 70, no. 8 (1992): 1603–12. http://dx.doi.org/10.1139/b92-202.
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The composition of a forest seed bank was estimated using two methods: (i) seed extraction, i.e., the physical separation of the seeds from the soil via flotation in a salt solution, and (ii) seedling emergence, i.e., the germination of seedlings from soil samples incubated under greenhouse conditions for 5 months. The extraction method predicted a density of 12 500 seeds∙m−2, while the emergence method detected 3800 émergents∙m−2. There was considerable disparity in species composition derived from the two methods. The extraction method identified 102 different taxa, with 22 species making up 99% of the seeds and 5.6 + 0.2 species per sample. In contrast, the emergence technique identified fewer species (60) but had more species per sample (7.6 + 0.2). Eleven species made up 99% of the emergents. Verbascum thapsus represented 34% of the seedlings in the emergence study but only 1 % of the extracted seeds. Members of the Polygonaceae represented 19% of the extracted seeds but less than 1 % of the seedling emergents. No tree or shrub species were found with the emergence method, although they represented 8% of the extracted seeds. There was a poor correlation between the estimates of species number, seed density, and diversity obtained from the two methods. The seed extraction method had considerably higher variability for these parameters. It is apparent from this study that the seedling emergence and seed extraction methodologies do not produce similar estimates of the seed bank composition. The differences are such that comparisons should not be drawn between studies using the different methods. Careful considerations should be given to both the objectives of the seed bank study and the relevant literature prior to the selection of an appropriate method. Key words: seed bank, method, composition, diversity, density, sample number.
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Akinkuolie, Ayomiposi Olayinka, Rafiu Olugbenga Sanni, Augustine O. Isichei, and Samson O. Oke. "Composition of native and alien invasive species in soil seed banks of five different physiognomies in Akure Forest Reserve, Ondo State, Nigeria." International Journal of Biological and Chemical Sciences 15, no. 2 (2021): 437–51. http://dx.doi.org/10.4314/ijbcs.v15i2.6.
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The study investigated the composition of native and alien invasive species in soil seed banks of five different vegetation physiognomies in Akure Forest Reserve Ondo State, Nigeria. This was done with a view to determining and providing an insight into the population dynamics of alien, invasive species for subsequent prediction of potential plant population of the extant population. Five distinct sites (Natural forest, Teak plantation, Taungya system, Taungya + Teak + Gmelina and Teak + Gmelina + Pinus Plantation) designated as A, B, C, D and E were selected in the Forest Reserve. Two plots 25 m x 25 m each were selected for sampling in each of the five distinct physiognomies. Five replicates soil samples were randomly collected at 0-15 cm soil depth in dry and rainy seasons in each site and they were subjected to seedlings emergence for six months to determine the density and species composition (natives or aliens and percentage contribution) of the seed bank. The results of the seedling emergence revealed that the seed bank was dominated by herbaceous stems and also the proportion of aliens to natives was low. Analysis of variance revealed that there was no significant difference (P>0.05) in the density of both the aliens and native species in sites A, B and C indicating similarities in the seed bank density of the aliens and natives in the three sites while in sites D and E, there was a significant difference (P<0.05) indicating dissimilarity in the seed bank density of the aliens and natives in the two sites.Keywords: Plant Ecology, Forest, Seedling Emergence, Seed Bank, Alien Species, Conservation.
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Hérault, Bruno, and Pierre Hiernaux. "Soil seed bank and vegetation dynamics in Sahelian fallows; the impact of past cropping and current grazing treatments." Journal of Tropical Ecology 20, no. 6 (2004): 683–91. http://dx.doi.org/10.1017/s0266467404001786.
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The soil seed bank in a 5-y-old Sahelian fallow was studied through seed extraction and compared with germinations recorded either in controlled conditions, ex situ in a glasshouse, or in the field. The influence of phosphorus fertilizer and mulch application during the preceding crop period, and that of seasonal grazing regimes applied the last 2 y of fallowing, were assessed on the composition of the seed stock. Ctenium elegans, Fimbristylis hispidula, Merremia pinnata and Phyllanthus pentandrus accounted together for 75% of extracted seeds, 72% of ex situ, and 62% of in situ seedlings. Mulch treatment was correlated with the first axis of the canonical correspondence analyses performed on the seedling datasets. Mulch and phosphorus fertilizer treatments held similar responses, as they both favoured the seed bank of erect dicotyledons such as P. pentandrus and Cassia mimosoides. On the whole, the effects of grazing remained modest compared with the residual effects of past crop management practices. However, seedling densities increased as a result of dry-season grazing, while the soil seed bank decreased with wet-season grazing. Grazing also reduced the spatial heterogeneity of the seed bank rather than the overall number of species.
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Chauhan, Bhagirath S., Gurjeet Gill, and Christopher Preston. "Influence of tillage systems on vertical distribution, seedling recruitment and persistence of rigid ryegrass (Lolium rigidum) seed bank." Weed Science 54, no. 4 (2006): 669–76. http://dx.doi.org/10.1614/ws-05-184r.1.
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Several studies were conducted to evaluate the effects of different tillage systems on the vertical seed distribution, seedling recruitment pattern, and persistence of the rigid ryegrass seed bank. Experiments were conducted in South Australia at two locations (Roseworthy Campus and Minlaton, a site on the Yorke Peninsula) in 2003 and 2005. The distribution of surface seeds through the soil profile was associated with the level of soil disturbance. The low–soil-disturbance tillage systems left more seed on the soil surface, whereas the high–soil-disturbance systems buried most of the seeds. The seedling recruitment of rigid ryegrass was lower under the low–soil-disturbance tillage systems than under the high–soil-disturbance tillage systems at both locations. The seedling recruitment was two- to fourfold greater under minimum tillage than under no-till. Not only was the seedling recruitment lower under the low–soil-disturbance tillage systems, biomass accumulation by rigid ryegrass seedlings was also lower under these systems. The carryover of residual viable seeds from one season to the next was similar between the tillage systems. However, seed decay under no-till (48 to 60%) was much greater than under minimum tillage (12 to 39%).
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Smith, Richard G., Randa Jabbour, Andrew G. Hulting, Mary E. Barbercheck, and David A. Mortensen. "Effects of Initial Seed-Bank Density on Weed Seedling Emergence during the Transition to an Organic Feed-Grain Crop Rotation." Weed Science 57, no. 5 (2009): 533–40. http://dx.doi.org/10.1614/ws-09-031.1.
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The transition period to certified organic production can present a significant weed management challenge for growers. Organic certification requires that prohibited fertilizers and pesticides must not have been used for 36 mo before harvest of the first organic crop. Understanding how organic management practices and initial weed seed-bank densities affect weed population dynamics during the transition period may improve weed management efficacy and adoption of organic practices. We examined how tillage systems (full or reduced) and cover crop species planted during the first transition year (rye or a mixture of timothy and red clover) affect the seedling densities of three common annual weed species, common lambsquarters, velvetleaf, and foxtail spp., during the 3-yr transition period. Weed seeds were applied in a one-time pulse at the beginning of the study at three densities, low, medium, and high (60, 460, and 2,100 seeds m−2, respectively), and cumulative seedling densities of each species were assessed annually. Treatment factors had variable and species-specific effects on weed seedling densities. In general, the full-tillage system, with an initial cover crop of timothy and red clover, resulted in the lowest density of weed seedlings following seed-bank augmentation. There was little consistent association between the initial densities of applied weed seeds in the weed seed bank at the start of the transition and weed seedling densities at the end of the transition period. This suggests that when multiple crop and weed cultural management practices are employed during the organic transition period, initial failures in weed management may not necessarily lead to persistent and intractable annual weed species management problems following organic certification.
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Chalermsri, Anussara, La-aw Ampornpan, and Witoon Purahong. "Seed Rain, Soil Seed Bank, and Seedling Emergence Indicate Limited Potential for Self-Recovery in a Highly Disturbed, Tropical, Mixed Deciduous Forest." Plants 9, no. 10 (2020): 1391. http://dx.doi.org/10.3390/plants9101391.
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Human activity negatively affects the sustainability of forest ecosystems globally. Disturbed forests may or may not recover by themselves in a certain period of time. However, it is still unclear as to what parameters can be used to reasonably predict the potential for self-recovery of human-disturbed forests. Here, we combined seed rain, soil seed bank, and seed emergence experiments to evaluate the potential for self-recovery of a highly disturbed, tropical, mixed deciduous forest in northeastern Thailand. Our results show a limited potential for self-recovery of this forest due to low seedling input and storage and an extremely high mortality rate during the drought period. There were 15 tree species of seedlings present during the regeneration period in comparison with a total number of 56 tree species in current standing vegetation. During the dry season, only four tree seedling species survived, and the highest mortality rate reached 83.87%. We also found that the correspondence between the combined number of species and composition of plant communities obtained from seed rain, soil seed bank, and seedling emergence experiments and the standing vegetation was poor. We clearly show the temporal dynamics of the seed rain and seedling communities, which are driven by different plant reproductive phenology and dispersal mechanisms, and drought coupled with mortality. We conclude that this highly disturbed forest needs a management plan and could not recover by itself in a short period of time. We recommend the use of external seed and seedling supplies and the maintenance of soil water content (i.e., shading) during periods of drought in order to help increase seedling abundances and species richness, and to reduce the mortality rate.
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Morin, H., and D. Laprise. "Seedling bank dynamics in boreal balsam fir forests." Canadian Journal of Forest Research 27, no. 9 (1997): 1442–51. http://dx.doi.org/10.1139/x97-113.
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Vdovenko, Serhii, Pavlo Shvydkyi, and Oleh Zatolochnyi. "INFLUENCE OF SEEDS AGE ON BIOMETRIC INDICATORS OF SWEET PEPPER UNDER CONDITIONS OF THE FOREST-STEPPE OF THE RIGHT-BANK OF UKRAINE." Agriculture and Forestry, no. 3 (October 30, 2020): 115–26. http://dx.doi.org/10.37128/2707-5826-2020-3-10.
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Sweet pepper takes one of the main places in the human diet among all vegetable plants. By the content of healthy vitamins, sweet pepper fruits have a better effect on the absorption of food than greenhouse cucumbers and tomatoes, and therefore sweet pepper is in great demand among consumers. The difference in the biometric and physiological parameters of sweet pepper of different age seedlings depends on the duration of growing seedlings. For the study, a sweet pepper variety of domestic selection Aphrodite was used. At the same time, biometric determinations were carried out over the sweet pepper plant: seedling height, stem diameter before planting, plant mass. The observation method monitored the onset of phenological phases of plant growth and development, and a laboratory method was used to determine biometric parameters. The appearance of the first leaf was established with clear control of the microclimate parameters and the provision of an appropriate irrigation regime. The formation of the first leaf was observed on the 7th day after emergence. It was proved that the formation of subsequent leaves, the growth of vegetative mass depended significantly on the age of the seedlings: the higher the seedling age, the more real leaves formed, due to the accumulation of dry matter in the leaves and the corresponding nutritional and temperature conditions. At the time of planting seedlings in open ground, at a constant place of vegetation, the plants were characterized by the presence of 4-6 real leaves, the height of the seedlings was 12-15 cm with a total weight of 10-12 g, there were no damage by pests and diseases on the surface of the leaves. As a result of different age of seedlings, studies have established that with a decrease in the age of seedlings, a tendency to delay flowering and fruiting was observed. The age of seedlings directly affects the budding of plants. So, in the variant where the seedlings are 60 days old, the period of budding was observed for 56 days, which was observed 1 day earlier than the control variant. Seedlings of sweet pepper aged 50 and 70 days passed into the budding phase for 57 days. However, seedlings aged 40 days showed a tendency to delay the onset of plant budding. It has been established that the height of the plant before planting ranged from 14.7 cm to 18.6 cm. The highest rate of plant growth has been distinquished in the variant where the seedlings were 70 days old. When using the seedling age of 70 days, the test value was 2 controls more than the control index. The option using 60 day old sweet pepper seedlings was characterized by slightly low leaf numbers. The experiments established that when using seedlings with an age of 40 days, the plants were characterized by the smallest number of leaves on the plant. The age of seedlings and biometric indicators depend on the growing conditions, the timely passage of the photosynthesis process, the provision of nutrients, water. When using the seedling age of 60-70 days, the biometric indicators of seedlings, namely the height of the plants, the number of glosses, the mass of the plant significantly exceeds the biometric indicators of seedlings with an age of 50 or 40 days. Keywords: sweet pepper, Aphrodite variety, seedling age, biometrics, vegetation, Right-Bank forest-steppe.
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Hu, A., J. Zhang, X. J. Chen, et al. "The composition, richness, and evenness of seedlings from the soil seed bank of a semi-arid steppe in northern China are affected by long-term stocking rates of sheep and rainfall variation." Rangeland Journal 41, no. 1 (2019): 23. http://dx.doi.org/10.1071/rj18025.
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The soil seed bank has a large influence on the potential for grassland restoration. This study aimed to characterise the composition, density, richness, and evenness of seedlings emerging from the soil seed bank under different sheep stocking rates, in a summer grazing system, in semi-arid China. Soil was sampled in 2015, a year with extreme drought conditions and in 2016, a normal rainfall year. The soil seed bank was assessed by measuring seedling emergence under laboratory conditions. Comprising 16 species, 85.4% of the seedlings were concentrated within a depth of 0–5cm. Drought significantly reduced the density and richness of the seedlings. Grazing increased the richness of seedlings by increasing the richness of aboveground species, and grazing significantly reduced the evenness of the seedlings by reducing the evenness of aboveground species. Drought significantly reduced the similarities between the seedlings and the aboveground species, whereas grazing increased similarities in both years. This study revealed that the density and richness of seedlings were higher in higher stocking rate in drought year. We conclude that negative effects on density, richness and evenness of the seedlings caused by drought can be overcome by rotational grazing especially at higher stocking rate.
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Erftemeijer, Paul L. A., Nicole Wylie, and Garnet J. Hooper. "Successful mangrove establishment along an artificially created tidal creek at Port Hedland, Western Australia." Marine and Freshwater Research 69, no. 1 (2018): 134. http://dx.doi.org/10.1071/mf17139.
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There is growing interest in innovative ways to minimise the environmental footprint of port developments. Herein we present results of a mangrove planting trial along an artificial tidal creek at Port Hedland, Western Australia. A 75 m-long tidal creek with exposed sloping and terraced banks was constructed, creating ~1000m2 of intertidal area in which 800 nursery-raised seedlings of four mangrove species (Avicennia marina, Rhizophora stylosa, Ceriops australis and Aegiceras corniculatum) were transplanted. Planting followed a randomised block design to test seedling performance against tidal elevation, bank design and erosion protection. After 3 years, 142 seedlings (18%) had survived. Another 1171 mangrove seedlings, dominated by A. corniculatum (75%) and Aegitialis annulata (15%), had recruited naturally into the site. Performance and survival of planted and recruited seedlings was significantly affected by tidal elevation (P=0.002), but not by bank design or erosion protection. A. marina showed highest survival (46%), followed by R. stylosa (18%). These results demonstrate that by creating appropriate environmental conditions conducive to mangrove growth, seedlings will recruit and establish naturally. Owing to the slow growth typical of semi-arid mangroves, it may take well over a decade before vegetation at this site is comparable to adjacent natural creeks.
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Lambers, Janneke Hille Ris, and James S. Clark. "Effects of dispersal, shrubs, and density-dependent mortality on seed and seedling distributions in temperate forests." Canadian Journal of Forest Research 33, no. 5 (2003): 783–95. http://dx.doi.org/10.1139/x03-001.
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Processes limiting recruitment of trees may have large impacts on forest dynamics. In this paper, we determined the effects of dispersal, shrubs (Rhododendron maximum), and density-dependent mortality on seed and seedling distributions of Southern Appalachian trees. We quantified the spatial distribution of seed rain, seed bank densities, first-year seedlings, and older than first-year seedlings in five vegetation plots. We fit models to these data assuming effects of limited dispersal, R. maximum (an understory shrub), and (or) density-dependent mortality (as well as a null model with none of these effects) and used best-fitting models to indicate which processes affected a particular species. We found that all factors examined limit species distributions, and thus, affect seedling dynamics. Seedling densities are higher near parent trees long after dispersal occurs. This pattern is less frequently observed for animal-dispersed species than for wind-dispersed species, presumably due to secondary dispersal of seeds by animals. Seedling densities of five species are decreased beneath R. maximum. Shade tolerance does not explain which species are affected, suggesting that factors other than low light are responsible for increased seedling mortality under this shrub. Our results suggest that density-dependent mortality affects four species, decreasing seedling densities close to parent trees. Dispersal, density-dependent mortality, and R. maximum all act in ways that may promote or limit diversity, illustrating that multiple factors are likely to control species diversity.
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Goets, Stefan A., Tineke Kraaij, and Keith M. Little. "Seed bank and growth comparisons of native (Virgilia divaricata) and invasive alien (Acacia mearnsii and A. melanoxylon) plants: implications for conservation." PeerJ 6 (August 21, 2018): e5466. http://dx.doi.org/10.7717/peerj.5466.
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Background Invasive alien plants with long-lived dormant seed banks and fast growth rates are difficult to manage. Acacia mearnsii and Acacia melanoxylon are two such invaders in the southern Cape of South Africa which occasionally co-occur with a native, ecologically analogous species, Virgilia divaricata. We compared the performance of these three species to determine potential for the native species to be used in management of the invasives. Methods We compared the study species in terms of (i) soil seed bank densities, their vertical distribution, and the viability of seeds underneath the canopies of mature trees; (ii) seedling growth from planted seeds over a period of three months; and (iii) growth rates of saplings over a period of 10 months in stands that have naturally regenerated in the field (these stands were dominated by A. mearnsii) and where saplings have been exposed to varying levels of competition from surrounding saplings. Results Seed bank densities differed significantly among species but not among soil depth classes. Acacia mearnsii had the highest seed bank densities (mean of 7,596 seeds m−2), followed by V. divaricata (938 seeds m−2) and A. melanoxylon (274 seeds m−2). Seed viability was high (87–91%) in all three study species and did not differ significantly among species or soil depth classes. As seedlings, V. divaricata significantly outgrew A. mearnsii in terms of height, root and shoot dry mass, and root:shoot ratio. Relative growth (the relationship between growth in height and initial height) was negative in the seedlings of both species. Trends during the sapling stage were opposite to those during the seedling stage; A. mearnsii (but not A. melanoxylon) saplings significantly outgrew V. divaricata saplings in height, while relative growth rates were positive in all species. Sapling growth of all species was furthermore uninfluenced by the collective biomass of surrounding competitors. Discussion Our findings suggest that amongst the measures considered, A. mearnsii’s success as an invader is primarily attributable to its large seed banks, and secondly to its vigorous growth in height as saplings. However, the superior growth performance of V. divaricata seedlings and no apparent negative effect of competition from the acacias on sapling growth show promise for its use in integrated management of the acacias.
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Antos, Joseph A., Audrey E. McPherson, and Heidi J. Guest. "Growth rates and crown morphology of Abies amabilis in the seedling bank of an ancient subalpine conifer forest." Canadian Journal of Forest Research 50, no. 11 (2020): 1124–30. http://dx.doi.org/10.1139/cjfr-2020-0087.
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The population dynamics of shade-tolerant tree species often includes a seedling bank — small trees persisting in the understory until canopy opening allows increased height growth. We studied the growth and morphology of 0.1–1.3 m tall Abies amabilis Douglas ex J. Forbes trees in the seedling bank of an ancient (>1300 years old) subalpine conifer forest on Vancouver Island, western Canada. We determined rates of height growth by counting growth rings at 10 cm intervals along the main stem and assessed crown morphology by measuring the length and location of each branch along the main stem. These small trees were very old (mean basal ring count, 112 years) and grew very slowly, taking on average 170 years to reach a height of 1 m. Instead of the typical conical form of open-grown Abies Mill., seedling bank individuals had flat crowns. Most branches were near the top of the main stem. The maximum distance along the main stem plus a branch was 1.6 times the main stem length, indicating that resource allocation is focused on lateral growth. The ability to grow slowly and adjust crown morphology allows seedling bank trees to persist for decades to centuries and to retain the possibility of release and growth into the canopy.
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Joley, Donald B., Donald M. Maddox, David M. Supkoff, and Aubrey Mayfield. "Dynamics of Yellow Starthistle (Centaurea solstitialis) Achenes in Field and Laboratory." Weed Science 40, no. 2 (1992): 190–94. http://dx.doi.org/10.1017/s0043174500057209.
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Studies were conducted to compare changes in germinability and/or viability of yellow starthistle achenes buried (in packets) in soil or stored dry in the laboratory, and to determine the rate of achene depletion from a soil seed bank. In one study, after 72 mo, 0 to 96% germinable achenes remained in packets buried 5 cm deep, and a mean above 99% after dry storage. In another study, total live (germinable plus viable) achenes declined from 100% at harvest to 77.6% after 24 mo of burial. Germinable pappus-bearing achenes remaining in packets increased with depth of burial. After 12 mo of burial, maximum survival of achenes occurred at depths of 5 cm or more. The density of yellow starthistle achenes and seedlings in a natural soil seed bank declined, when achene rain was prevented, to 3.9 and 1.1% of initial density, respectively, after 36 mo. Decline was attributed primarily to seedling emergence and achene death. Achene density in the upper 2.5 cm of soil appeared to be a good predictor of seedling emergence after autumn rains.
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Forcella, Frank, Robert G. Wilson, Jack Dekker, et al. "Weed seed bank emergence across the Corn Belt." Weed Science 45, no. 1 (1997): 67–76. http://dx.doi.org/10.1017/s0043174500092493.
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Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of these species were as follows: giant foxtail, 31.2 (84%); velvetleaf, 28.2 (66); kochia, 25.7 (79); Pennsylvania smartweed, 25.1 (65); common purslane, 15.4 (135); common ragweed, 15.0 (110); green foxtail, 8.5 (72); wild proso millet, 6.6 (104); hairy nightshade, 5.2 (62); common sunflower, 5.0 (26); yellow foxtail, 3.4 (67); pigweed species, 3.3 (103); common lambsquarters, 2.7 (111); wild buckwheat, 2.5 (63), and prostrate knotweed, 0.6 (79). Variation among site-years, for some species, could be attributed to microclimate variables thought to induce secondary dormancy in spring. For example, total seasonal emergence percentage of giant foxtail was related positively to the 1st date at which average daily soil temperature at 5 to 10 cm soil depth reached 16 C. Thus, if soil warmed before mid April, secondary dormancy was induced and few seedlings emerged, whereas many seedlings emerged if soil remained cool until June.
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McGee, Ann, and M. C. Feller. "Seed banks of forested and disturbed soils in southwestern British Columbia." Canadian Journal of Botany 71, no. 12 (1993): 1574–83. http://dx.doi.org/10.1139/b93-192.
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The species composition and density of seed banks in the forest floors and mineral soils of several undisturbed (immature, midseral forests) and disturbed (transmission line rights-of-way) ecosystems in southwestern British Columbia were estimated using the seedling-emergence method. The total soil surface area sampled was 9.4 m2. Germination behaviour of seven dominant species in response to depth of burial and substrate was also studied in a greenhouse experiment. A total of 16 289 seedlings germinated, representing 62 native and naturalized vascular plant species and several unidentified grass species. Most seedlings emerged from the forest floor, and the number of germinants generally decreased with increasing sample depth. Drier ecosystems had the lowest number and density of germinants. Burial depth significantly affected germination of all species tested. Mineral soil was equal, or superior, to forest floor as a germination substrate for all species tested. Depth–substrate interactions for several species indicated that the pattern of influence of burial depth in relation to substrate varied with species. Caution is urged extrapolating greenhouse seed-bank studies to potential weed populations in the field. Establishment of species from the seed bank will be a function of the depth to which the soil is disturbed and the kind of disturbance (burning, scarification) imposed. Key words: British Columbia, Coastal Western Hemlock zone, seed bank, seed germination, seed diversity, seed density.
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Anderson, R. L. "Seedling Emergence of Winter Annual Grasses as Affected by Limited Tillage and Crop Canopy." Weed Technology 12, no. 2 (1998): 262–67. http://dx.doi.org/10.1017/s0890037x00043797.
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Jointed goatgrass and downy brome continue to plague winter wheat producers in the western United States. Because there are no effective herbicides for in-crop control of these weeds, producers are seeking cultural practices that stimulate seed germination and deplete the soil seed bank. We determined the effect of limited tillage and crop canopy on seedling emergence of these grasses. One tillage operation with a sweep plow increased jointed goatgrass seedling emergence 74% in the first year but did not affect emergence in later years. Downy brome emergence was not affected by tillage. Jointed goatgrass seedlings emerged over 5 yr, whereas downy brome did not emerge after 3 yr. Seedling emergence of both species was two times greater in corn and barley than in proso millet. Producers will accrue more benefit for seedbank management with cultural strategies such as alternative rotations and competitive wheat canopies than with limited tillage using a sweep plow.
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Jones, RM, and GA Bunch. "The effect of stocking rate on the population dynamics of siratro in siratro (Macroptilium atropurpureum)-setaria (Setaria sphacelata) pastures in south-east Queensland. II. Seed set, soil seed reserves, seedling recruitment and seedling survival." Australian Journal of Agricultural Research 39, no. 2 (1988): 221. http://dx.doi.org/10.1071/ar9880221.
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Measurements were made of the seed set, seed content in cattle faeces, soil seed reserves, seedling regeneration and seedling survival of Siratro (Macroptilurn atropurpureum) in south-east Queensland. Measurements were made from 1972 to 1985 in pastures of Siratro/setaria (Setaria sphacelata) sown in 1968 and stocked at 1.1, 1.7 and 2.3 and at 3.0 (1969-1973) reduced to 2.0 (1974-1985) heifers ha-1. Siratro seed set and seedling demography were markedly affected by stocking rate. At the highest stocking rate, Siratro yields were low and seed input ceased after 1972, yet appreciable seedling recruitment from the soil seed bank was maintained for a further 10 years. At the lightest stocking rate (1.1 heifers ha-1), seed set and soil seed reserves were highest, but seedling recruitment was of little importance as almost all seedlings died. Seedling recruitment and survival were best at an intermediate stocking rate (1.7 heifers ha-1), where they were the key to long-term persistence of Siratro. Soil seed reserves of Siratro ranged from 500 m-2 under light stocking to < 100 m-2 after several years of heavy stocking. Very little seed was recovered in cattle faeces. Likely factors responsible for seedling death (light, water, nutrients, grazing, frosting and insect damage) are discussed. The limitations of seed set and seedling regeneration in the persistence of Siratro are contrasted with some other perennial pasture legumes. Studies of this type can help in qualitatively predicting long-term persistence of pasture legumes under different conditions of management and climate.
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Parent, Sylvain, and Jean-Claude Ruel. "Chronologie de la croissance chez des semis de sapin baumier (Abies balsamea (L.) Mill.) après une coupe à blanc avec protection de la régénération." Forestry Chronicle 78, no. 6 (2002): 876–85. http://dx.doi.org/10.5558/tfc78876-6.
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The method of harvesting with protection of the advanced regeneration consists of a complete removal of the main canopy to release a seedling bank established under the overstory shade. After harvesting, seedlings acclimated to understory conditions could suffer from moisture stress, especially the small, juvenile seedlings (less than six years). The objective of the study is to determine the capacity of understory-acclimated balsam fir seedlings to respond positively and immediately to release. The response to release was studied in two seedling populations belonging to two distinct climatic regions of Quebec, the Western and the Eastern sections of the balsam fir-white birch ecological domain. Results show that the response patterns were similar in both populations. Response to release occurred in two steps. One year after harvesting, basal ring width was on the average five times larger than prior to harvesting (p > 0.001). Height growth only became significantly higher the second year after release (p < 0.001). On average, juveniles showed higher height growth rates (height growth/height) than older seedlings. This rate was negatively correlated to seedling height at harvesting (r = -0,68, p < 0.001). Our study clearly shows that balsam fir seedlings can respond immediately and positively to large openings. The strong response of juvenile seedlings to release indicates that these can contribute significantly to the future stand. The geographic and climatic differences between the two stands under study suggest that these observations apply to a wide range of balsam fir stands. Key words: advance growth, balsam fir, release
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Dow, Melissa A., and Christa R. Schwintzer. "Seed germination, seedling emergence, and seed bank ecology of sweet fern (Comptonia peregrina(L.) Coult.)." Canadian Journal of Botany 77, no. 9 (1999): 1378–86. http://dx.doi.org/10.1139/b99-081.
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We examined seed-bank seeds of sweet fern (Comptonia peregrina (L.) Coult.), an actinorhizal nitrogen-fixing shrub, to determine their distribution in the soil and to identify the factors that stimulate them to germinate following removal of the vegetation. Seeds were extracted from the soil of adjacent field and forest sites currently lacking sweet fern in Orono, Maine. Both sites contained approximately 2000 seeds·m-2with the greatest concentration at a depth of 60-80 mm. The seeds were 4.0-5.5 mm long, enclosed by a pitted, woody pericarp, and 8% contained embryos. Many seedlings emerged in disturbed plots (vegetation removed and upper soil mixed) in May and June 1997, but none appeared after 24 July. Seeds collected in May and June germinated readily in a growth chamber (30-45% germination) whereas only 2-5% of July- and August-collected seeds germinated indicating induction of secondary dormancy. August-collected seeds showed strong germination after >=15 days of moist chilling at 4°C indicating relief of secondary dormancy by chilling. Temperature fluctuation with an amplitude of 10°C strongly stimulated germination. Presence of annual secondary dormancy cycles and stimulation by strong temperature fluctuation assures that seed-bank seeds germinate under conditions that allow the seedlings to become established.Key words: actinorhizal plants, Comptonia peregrina, germination ecophysiology, secondary dormancy, seed bank, seedling emergence.
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Rodríguez, Claudia, and Maria Alice Garcia. "Seed-bank dynamics of the tropical weedSida rhombifolia(Malvaceae): incidence of seedling emergence, predators and pathogens." Seed Science Research 19, no. 4 (2009): 241–48. http://dx.doi.org/10.1017/s0960258509990146.
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AbstractArrowleaf sida (Sida rhombifolia) is a tropical weed that grows in disturbed areas. Its control by hand pulling and mowing are only partially effective because arrowleaf sida is difficult to pull and quickly sprouts after cutting. We studied the seed-bank dynamics ofS. rhombifoliain the region of Campinas, São Paulo State, Brazil for 2 years, following a known number of seeds placed artificially at five burial depths. Predators and pathogens were responsible for the loss ofc.40% of the seeds during the first year of the experiment. The importance of predation declined with depth. Mortality due to fungal attack did not differ among the burial depths, except for seeds placed at the surface (where it was negligible). Seedling emergence only occurred during the first year, after the beginning of the rainy period and when the study area was still free of a dense vegetation cover. Seedlings did not emerge from depths greater than 5 cm. We conclude that seedling emergence and death are significant causes of seed losses from the seed bank ofS. rhombifoliabut their relative importance is highly dependent on depth of burial.
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Sohrabikertabad, S., A. Ghanbari, H. R. Mohassel, Mohamad, M. N. Mahalati, and J. Gherekhloo. "Effect of desiccation and salinity stress on seed germination and initial plant growth of Cucumis melo." Planta Daninha 31, no. 4 (2013): 833–41. http://dx.doi.org/10.1590/s0100-83582013000400009.
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Smellmelon, an annual invasive weed of soybean production fields in the north of Iran, reproduces and spreads predominately through seed production. This makes seed bank survival and successful germination essential steps in the invasive process. To evaluate the potential of Smellmelon to invade water-stressed environments, laboratory studies were conducted to investigate the effect of desiccation and salinity at different temperatures on seed germination and seedling growth of Cucumis melo. Seeds were incubated at 25, 30, 35 and 40 ºC in the darkness in a solution (0, -0.2, -0.4, -0.6, -0.8, 1 and 1.2 MPa) of a salt (NaCl), and in a solution (0, -2, -4, -6, -8, -10, -12 bar) of PEG-6000 (Polyethylene glycol), in two separate experiments. The results showed that the highest percentage and rate of germination occurred at 35 ºC in salt concentrations of 0, -0.2, -0.4 MPa and PEG concentrations of 0, -2, -4 bar. Increasing the concentration of salt (NaCl) and PEG limited germination, seedling growth and water uptake but increased the sodium content in the seedlings. No significant difference was observed among 0, -0.2 and -0.4 MPa of NaCl and among 0, -2 and -4 bar of PEG concentration at 35 ºC. The negative effects of PEG were more than those of NaCl on germination percentage and germination rate. Increased stress levels lead to reduction of root and shoot length, and SVL of seedlings. Na+ content of seedling decreased with limited seedling growth of C. melo.
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Kwiatkowska-Falińska, Anna J., Dorota Panufnik-Mędrzycka, Maciej Wódkiewicz, Izabela Sondej, and Bogdan Jaroszewicz. "The effects of different types of woodstand disturbance on the persistence of soil seed banks." Acta Societatis Botanicorum Poloniae 80, no. 2 (2011): 149–57. http://dx.doi.org/10.5586/asbp.2011.025.
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The research was conducted on four patches of thermophilous oak wood in Białowieża Primeval Forest: A – with a woodstand: oak + approx. 30-year-old hornbeam + hornbeam brushwood; B – with a hornbeam stand formed by natural seed fall after logging (ca. 1920) oaks; C – after logging oaks and replanted (ca. 1965) with pine and oak; D – with a natural low-density oak stand. Species composition and seed bank density were estimated using the seedling emergence method. Seedling emergence was observed over two vegetation seasons. Research demonstrated that: 1) the species abundance of the seed banks depends on canopy cover (A, B approx. 50 species; C, D approx. 70 species); 2) the floristical similarity (Sørensen's index) of the seed bank and ground vegetation is higher in the undisturbed patch D (0.50) than in disturbed patches (0.30-0.35); 3) species diversity in plots A, B, C, D (H'=12.5; 13.4; 15.5; 16.9) and seed bank density per m<sup>2</sup> (432.5; 958.0; 1486.5; 2268.0) are negatively correlated with the degree of patch shading; 4) the average weight of diaspores in the seed banks of shady plots is lower (A, B approx. 0.003 g) than that of sunny plots (C, D approx. 0.08 g); 5) the share of long-lived diaspores increases in patches after logging.
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Mcgill, C. R., K. L. Kitchen, and H. A. Outred. "Regeneration of Agathis australis and associated species in a native bush stand on Limestone Downs." NZGA: Research and Practice Series 14 (January 1, 2010): 23–31. http://dx.doi.org/10.33584/rps.14.2008.3186.
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A predator-proof fence enclosing 270 m2 of predominantly kauri (Agathis australis) bush on Limestone Downs was erected in February 2004. Regeneration of A. australis and other seed-dispersed species was monitored in permanent quadrats laid out within and immediately outside the enclosure. The quantity of viable A. australis seed entering the enclosure by natural dispersal and extent of viable A. australis seed within the soil seed bank were measured. Two thirds of the viable seed dispersed was lost, probably through mammalian predation. Eleven species were found in the soil seed bank. No viable A. australis seed was found in the soil seed bank. Seed rain was the source of viable A. australis seed. Regeneration of A. australis was greater within the protected environment of the predator-proof fence. There was a decline in seedling numbers between May 2007 and April 2008 both inside and outside the predator-proof fence suggesting that predation was not the only factor influencing seedling survival. Keywords: Agathis australis, Xcluderâ„¢ fence, seed predation, seedling survival, regeneration, seed rain
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Anwahi, Abdulrazzaq, Mohamed Abdel Rahim Al Zarouni, Ahmed Al Janahi, and Thomas Cherian. "Feasibility studies on mangrove Avicennia marina cultivation below ground level along the bank of a dug-out pond." Marine and Freshwater Research 49, no. 4 (1998): 359. http://dx.doi.org/10.1071/mf97117.
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The feasibility of cultivating grey mangrove A. marina on the bank of a dug-out pond at 2.25 m below ground level ~500 m inland at Umm Al Qaiwain, United Arab Emirates, has been studied. A seedling emergence of 74% to 84% was observed within 10 days of sowing 796 seeds (propagules). Average values of shoot height, number of leaves and number of branches decreased with distance from the water line. Growth rates of the seedlings were reasonably good (0.19–0.26 cm day-1).
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Oldham, Michelle, and Corey V. Ransom. "Goatsrue (Galega Officinalis) Seed Biology." Weed Science 57, no. 2 (2009): 149–54. http://dx.doi.org/10.1614/ws-08-105.1.
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Goatsrue is an introduced perennial plant which has proven to have great invasive potential, leading to its classification as a noxious weed in many states and at the federal level. Very little research has been done on its basic biology. Physical dormancy of mature goatsrue seed was tested through scarification with sulfuric acid for up to 60 min resulting in 100% germination. Comparison of dormancy for 26-yr-old and 6-mo-old goatsrue seed indicated that aged seeds had reduced dormancy levels compared to newly harvested seeds. Maximum germination was similar among the 6-mo old and 26-yr-old seed lots, suggesting no loss of viability had occurred in seed stored dry for 26 yr. Goatsrue seedling emergence was inversely related to burial depth, and decreased as burial depth increased. Emergence of seed buried at 0.5 to 3.0 cm soil depth was 93 to 87%, respectively, and no emergence occurred from 12 and 14 cm. When the soil seed bank of five goatsrue-infested areas was sampled, the largest density of seeds found was 74,609 seeds m−2 while the lowest was 14,832 seeds m−2. Viability and dormancy of seeds recovered from the soil seed bank survey ranged from 91 to 100% and 80 to 93%, respectively. Management, which reduces the soil seed bank and controls emerging seedlings, is as essential as control of mature goatsrue plants in order to avoid seedling establishment and reinvasion of a location.
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Gracia, Marc, Javier Retana, and Francesc Xavier Pic�. "Seedling bank dynamics in managed holm oak (Quercus ilex) forests." Annals of Forest Science 58, no. 8 (2001): 843–52. http://dx.doi.org/10.1051/forest:2001167.
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Baraloto, Christopher, and Deborah E. Goldberg. "Microhabitat associations and seedling bank dynamics in a neotropical forest." Oecologia 141, no. 4 (2004): 701–12. http://dx.doi.org/10.1007/s00442-004-1691-3.
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Lee, Philip. "The impact of burn intensity from wildfires on seed and vegetative banks, and emergent understory in aspen-dominated boreal forests." Canadian Journal of Botany 82, no. 10 (2004): 1468–80. http://dx.doi.org/10.1139/b04-108.
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This paper compares seed and vegetative banks, and the emergent understory in unburned, lightly burned, and intensely burned patches within an aspen-dominated boreal forest in northeastern Alberta, Canada. Propagule banks were measured immediately after the fire, while the understory was surveyed 2 years later. Seedling and shoot emergence techniques were used to assess the abundance and assemblage of species within seed and vegetative banks. Median seed density was ordered unburned > lightly burned = intensely burned patches. A cumulative index of vegetative bank abundance was ordered unburned > lightly burned > intensely burned patches. Species assemblages were significantly different amongst burn intensities for seed banks and emergent understory. Vegetative bank assemblages were significantly different between unburned and burned patches but not between lightly and intensely burned patches. Furthermore, seed and vegetative bank assemblages within each burn intensity were also significantly different. Indicator species analysis suggested that all significant differences were due largely to broad assemblage differences rather than a few unique species. Ordination with nonmetric multidimensional scaling correspondence analysis separated seed and vegetative banks, and emergent understory along two axes (88.8% of the total variation). The first axis (50.3% of the total variation) indicated that the unburned and lightly burned species assemblages were more similar to the vegetative bank, while the intensely burned patches were more similar to the seed bank. The second axis (38.5% of the total variation) placed vegetative banks closer to emergent vegetation than seed banks.Key words: seed bank, bud bank, vegetative bank, aspen, boreal, fire.
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Presotto, Alejandro, Fernando Hernández, Mauricio Casquero, et al. "Seed bank dynamics of an invasive alien species, Helianthus annuus L." Journal of Plant Ecology 13, no. 3 (2020): 313–22. http://dx.doi.org/10.1093/jpe/rtaa016.
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Abstract Aims The ability to form persistent seed banks is one of the best predictors of species’ potential to establish in new ranges. Wild sunflower is native to North America where the formation of persistent seed banks is promoted by disturbance and it plays a key role on the establishment and persistence of native populations. However, the role of the seed banks on the establishment and persistence of invasive populations has not been studied. Here, we evaluated the role of seed bank and disturbance on the establishment and fitness, and seed persistence in the soil in several sunflower biotypes collected in ruderal (wild Helianthus annuus) and agrestal (natural crop–wild hybrid) habitats of Argentina as well as volunteer populations (progeny of commercial cultivars). Methods In a seed-bank experiment, we evaluated emergence, survival to reproduction, survival of emerged seedlings, inflorescences per plant and per plot under disturbed and undisturbed conditions over 2 years; in a seed-burial experiment, we evaluated seed persistence in the soil over four springs (6, 18, 30 and 42 months). Important Findings Overall, seedling emergence was early in the growing season (during winter), and it was promoted by disturbance, especially in the first year. Despite this, the number of inflorescences per plot was similar under both conditions, especially in ruderals. In the second year, emergence from the seed bank was much lower, but the survival rate was higher. In the seed-burial experiment, genetic differences were observed but seeds of ruderals and agrestals persisted up to 42 months while seeds of the volunteer did not persist longer than 6 months. The agrestal biotype showed an intermediate behavior between ruderals and volunteers in both experiments. Our findings showed that wild and crop–wild sunflower can form persistent seed banks outside its native range and that disturbance may facilitate its establishment in new areas.