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1
Leon, Ramon G., e Micheal D. K. Owen. "Artificial and natural seed banks differ in seedling emergence patterns". Weed Science 52, n. 4 (agosto 2004): 531–37. http://dx.doi.org/10.1614/ws-03-048r2.
Testo completoAbstract (sommario):
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.
2
Joshi, Bal Krishna. "Indigenous Seeds, Seed Selection and Seed Bank for Sustainable Agriculture". Grassroots Journal of Natural Resources 04, n. 04 (30 dicembre 2021): 13–26. http://dx.doi.org/10.33002/nr2581.6853.040402.
Testo completoAbstract (sommario):
Indigenous seeds are grown by the farmers over the years with a strong influence from local natural factors. Such seeds have a higher level of intrapopulation variations and the capacity of buffering the adverse factors. Understanding indigenous seeds along with their diversity are useful to diversify their uses, to assess conservation status, to know the factors making farming areas red zone, and to improve their performance. Selection is the simplest and most common method for the improvement of crop varieties. The variation must be created and maintained to impose selection. Different types of selection can be considered depending on the mode of reproduction of crops. Response to selection and correlated response are estimated to make the selection process more effective. Many different selection approaches can target either developing monomorphic or polymorphic varieties. There are five selection units and can be applied in five crop stages. Farmers’ criteria need to be considered during selection process. Based on the genotypic classes, there are three types of selection namely stabilizing selection, directional selection, and disruptive selection. The most simple and common selection methods are pure lines, mass selection, and class-bulking selection. Orthodox seeds in short, medium, and long-term storage facilities are conserved as a seed bank. Major types are household seed banks, community seed banks, national seeds, natural seed banks, and global seed banks. A seed bank is for assuring the availability of crop diversity for research, study, and production. The common works in seed banks are diversity collection, regeneration, characterization, multiplication, and distribution along with online database management.
3
Caballero, I., J. M. Olano, A. L. Luzuriaga e A. Escudero. "Spatial coherence between seasonal seed banks in a semi-arid gypsum community: density changes but structure does not". Seed Science Research 15, n. 2 (giugno 2005): 153–60. http://dx.doi.org/10.1079/ssr2005206.
Testo completoAbstract (sommario):
Seed banks play a crucial role in arid plant communities because they confer stability and long-term persistence. However, seed banks have high temporal and spatial variability, with dramatic changes in density and composition. The aim of this study was to test whether seasonal change affected seed bank community structure and spatial pattern. Moreover, we wanted to know if the effect driven by environmental factors on the seed bank was constant year round. We sampled the seed bank at 188 points along seven parallel transects through a gypsum system in central Spain. Soil samples were taken twice (September and April) in contiguous plots. In each plot we measured environmental parameters, including micro- and macroslope, vegetation band, shrub cover, lichen crust cover and landform. A nearly threefold decrease in seed bank density occurred between September (16,230 seeds m–2) and April (5960 seeds m–2). Seasonal changes in density varied widely among species; however, a seed bank was present for most species at both sampling dates. For several well-studied species (Lepidium subulatum and Helianthemum squamatum), seed losses were within the range of losses by emergence reported in the literature. In both seasons, seed bank composition was controlled mainly by community band and microslope. Sampling season had a significant, but minor effect on seed bank composition. Moreover, a high spatial correlation existed in terms of seed density and richness through the two studied seasons. These results show that the seed bank keeps a constant structure even under substantial variation in density.
4
Hulme, P. E. "Post-dispersal seed predation and seed bank persistence". Seed Science Research 8, n. 4 (dicembre 1998): 513–19. http://dx.doi.org/10.1017/s0960258500004487.
Testo completoAbstract (sommario):
AbstractThis study examines whether post-dispersal seed predators could be an important selective force in determining the seed bank strategies of grassland plants. It tests the hypothesis that species with persistent seed banks should sustain proportionally less predation of buried seeds than species which have transient seed banks and that this should be true irrespective of seed size. Results are drawn from a field experiment examining the relative susceptibility of surface versus buried seeds for 19 herbaceous taxa exhibiting different degrees of seed bank persistence. The data were consistent with the hypothesis that seed predators (rodents) influence the seed bank characteristics of seeds. Rodents removed proportionally more large seeds than small seeds and removed a smaller proportion of seeds with persistent rather than transient seed banks, independently of seed size. On average, burial reduced seed removal by almost 50%. The decrease in rates of seed removal following burial was marked for seeds with persistent seed banks but negligible for seeds with transient seed banks. Herbaceous plants with relatively large seeds (seed mass > 1 mg) that form persistent seed banks were either completely avoided or only consumed in small quantities by rodents. In contrast, large-seeded species with transient seed banks suffer high rates of seed predation. Models of life-history evolution predict trade-offs between seed dormancy and seed mass since dormancy and seed size are correlated traits that both reduce risk in variable environments and thus will show patterns of negative covariation. This paper presents an alternative explanation for this trade-off based on experimental evidence of a negative relationship between seed bank persistence and predation risk.
5
Warr, Susan J., Ken Thompson e Martin Kent. "Seed banks as a neglected area of biogeographic research: a review of literature and sampling techniques". Progress in Physical Geography: Earth and Environment 17, n. 3 (settembre 1993): 329–47. http://dx.doi.org/10.1177/030913339301700303.
Testo completoAbstract (sommario):
The article highlights a comparatively neglected area of biogeographical research - seed banks and the distribution of seeds in the soil. The article reviews some of the relevant literature on seed banks and the methods for their study. Attention is focused on aspects of seed banks of particular relevance to biogeographers, with detailed examples drawn from seed bank studies in both temperate and tropical environments. In the review of the seed bank literature, the topics covered include the seed banks of successional communities and the size of seed banks in different vegetation types. The species composition of seed banks in different plant communities is discussed, particularly the degree of correlation between the species composition of seed banks and associated ground flora. The relationships between seed persistence, depth of burial in the soil and soil properties, such as moisture and pH, are explored. Seed bank heterogeneity is examined and a number of studies which have attempted to describe and measure the spatial variability of seed banks are summarized. Ways of classifying seed banks in terms of seed bank strategies are explained. The role of seed banks in conservation is discussed, for example in restoration projects, where preferred species have been lost from the vegetation but survive in the seed bank. The relevance of seed banks for the conservation of rare species and in landscape management is considered. Lastly, the contribution of seed banks to the recovery of vegetation following disturbance in various plant communities is discussed. In the review of seed bank sampling techniques, the subjects considered include methods of sample collection, the sampling intensity required for reliable estimates of seed density, a consideration of the relative merits of random and systematic sample distribution, as well as the importance of the timing of sampling. Various methods for the estimation of seed numbers in samples are appraised; these either involve extraction of seeds from the soil, followed by seed identification or enumeration by germination and seedling identification. Problems of analysing seed bank data are considered and several useful techniques for data analysis are suggested. Finally, the article draws attention to areas of future seed bank research for biogeographers and plant ecologists.
6
Hossain, MM, e M. Begum. "Soil weed seed bank: Importance and management for sustainable crop production- A Review". Journal of the Bangladesh Agricultural University 13, n. 2 (20 luglio 2016): 221–28. http://dx.doi.org/10.3329/jbau.v13i2.28783.
Testo completoAbstract (sommario):
The seed bank is the resting place of weed seeds and is an important component of the life cycle of weeds. Seed banks are the sole source of future weed populations of the weed species both annuals and perennials that reproduce only by seeds. For this reason, understanding fate of seeds in the seed bank can be an important component of overall weed control. When weed seeds enter the seed bank, several factors influence the duration for which seeds persist. Seeds can sense the surrounding environment in the seed bank and use these stimuli to become dormant or initiate germination. Soil and crop management practices can directly influence the environment of seeds in the soil weed seed bank and can thus be used to manage seed longevity and germination behavior of weed seeds.J. Bangladesh Agril. Univ. 13(2): 221-228, December 2015
7
Butler, Jack, e Kara Paintner. "Rangeland Recovery Potential: Soil Seed Content and Seed Viability". UW National Parks Service Research Station Annual Reports 14 (1 gennaio 1990): 63–65. http://dx.doi.org/10.13001/uwnpsrc.1990.2879.
Testo completoAbstract (sommario):
In most plant communities, soil contains a seed bank (population of dormant seeds), (Harper 1977), which provides a partial record of past and present vegetation (Major and Pyott 1966, Johnson and Anderson 1986). Seed banks are continuously rejuvenated by a "seed rain", from vegetation located on- and off-site. If existing communities are disturbed or destroyed, the seed bank provides a potential source of propagules during succession (Egler 1954, Connell and Slatyer 1977). Consequently, seed banks may serve as an index in predicting what vegetation changes might occur if environmental conditions are favorable for germination (Harper 1977). The objectives of this study are to 1. evaluate the viable seed bank within grazed and relict pinyon-juniper and blackbrush/Indian ricegrass communities in Glen Canyon National Recreation Area (GCNRA), 2. assess the ability of these communities to recover following a disturbance, using their respective seed banks as indicators of recovery potential, and 3. address the suitability of using seed banks to monitor and predict community level composition changes in response to various intensities of grazing.
8
Salazar, Ana, Guillermo Goldstein, Augusto C. Franco e 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, n. 2 (13 gennaio 2011): 103–16. http://dx.doi.org/10.1017/s0960258510000413.
Testo completoAbstract (sommario):
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.
9
Landenberger, Rick E., e James B. McGraw. "Seed-bank characteristics in mixed-mesophytic forest clearcuts and edges: Does "edge effect" extend to the seed bank?" Canadian Journal of Botany 82, n. 7 (1 luglio 2004): 992–1000. http://dx.doi.org/10.1139/b04-080.
Testo completoAbstract (sommario):
Little is known about the seed banks of mixed-mesophytic forest clearcuts or their associated forest edges. Seed banks were described and compared to better understand how seed density, species richness, and composition change with increasing distance from clearcuts. Thirty-two taxa were found in the seed bank of clearcuts, and 44 were found in adjacent forest edges. Annuals represented 41% of seeds in clearcuts, but only 8% in edges, while trees and shrubs represented 3% in both areas. Seed-bank density and species richness varied significantly within and between clearcuts, but clearcuts were no different in seed-bank density and richness from interior forest seed banks. Seed-bank density declined significantly with distance from clearcuts on west-facing forest edges, but demonstrated no discernable spatial pattern on south-facing edges. Overall, edge effects from clearcutting on adjacent forest seed banks were demonstrated in total seed density and in several common wind-dispersed, early-successional herbaceous species, including Erechtites hieraciifolia (L.) Raf. and Lobelia inflata L., and Vitis, a common ingestion-dispersed species. The seed-shadow edge effect may influence both current and future community characteristics and population dynamics of vegetation in mixed-mesophytic forest edges adjacent to clearcuts.Key words: seed banks, clearcutting, edge effects, mixed-mesophytic forest, West Virginia.
10
Ebersole, James J. "Role of the seed bank in providing colonizers on a tundra disturbance in Alaska". Canadian Journal of Botany 67, n. 2 (1 febbraio 1989): 466–71. http://dx.doi.org/10.1139/b89-065.
Testo completoAbstract (sommario):
Numbers of germinable seeds in soils from four undisturbed communities at an Alaskan Arctic Coastal Plain site ranged from 70 to 600 m−2 and numbers of distinct taxa were two to nine. Stratified soils contained more germinable taxa than unstratified soils, suggesting that seed banks in Alaskan tundra are more diverse than shown by earlier studies using unstratified soils. In contrast to temperate seed banks, which often contain early successional species no longer present in the vegetation, all seed bank taxa at this site occur within a short distance of the sample sites because of long persistence of the communities. Of the common colonizers on a nearby 30-year-old disturbance, Betula nana, Poa arctica, Salix spp., and Arctagrostis latifolia are absent or present in only small amounts in the seed bank and apparently colonize mainly from seeds dispersed following disturbance. Eriophorum angustifolium, another common colonizer, is present in the seed bank of wet areas and Carex bigelowii and C. aquatilis are abundant in the seed bank of several communities. Germination from the seed bank is an important means of colonizing disturbances for these taxa. No trend in seed bank size with intensity of disturbance (cryoturbation) was found, and comparison with other studies shows that seed bank size in Eriophorum vaginatum tussock tundra decreases with latitude.
11
Komulainen, M., M. Vieno, V. T. Yarmishko, T. D. Daletskaja e 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, n. 2 (1 febbraio 1994): 143–49. http://dx.doi.org/10.1139/b94-019.
Testo completoAbstract (sommario):
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.
12
Graham, AW, e MS Hopkins. "Soil Seed Banks of Adjacent Unlogged Rain-Forest Types in North-Queensland". Australian Journal of Botany 38, n. 3 (1990): 261. http://dx.doi.org/10.1071/bt9900261.
Testo completoAbstract (sommario):
The size and floristic composition of soil seed banks under four adjacent, unlogged and structurally different rainforest types were assessed by exposing 17 surface soil samples (to 40mm depth) to germination-house conditions. The mean size of the seed bank in the undisturbed forest types was 240 seeds m-2 (s.d. 139). Seeds of secondary species dominated the soil seed banks in all forest types, although weed seeds constituted only 0.6-4.0%. Some forest types had characteristic component secondary species in the buried seed bank. Agglomerative classification and multidimensional scaling analysis of quantitative sample data indicated that the parent structural-environmental forest type was the dominant influence in determining composition of the soil seed banks. Comparisons of the seed banks of the intact rainforest with those of nearby disturbed forests showed the former to be 35 to 50% smaller in total size, and lacking in some distinctive secondary species. It was concluded that disturbance, both within and adjacent to rainforest, may influence soil seed bank compositions, and hence future patterns of regeneration.
13
Leckie, Sara, Mark Vellend, Graham Bell, Marcia J. Waterway e Martin J. Lechowicz. "The seed bank in an old-growth, temperate deciduous forest". Canadian Journal of Botany 78, n. 2 (7 aprile 2000): 181–92. http://dx.doi.org/10.1139/b99-176.
Testo completoAbstract (sommario):
We assessed the size and composition of the seed bank in 31 plots representing a range of habitats within an old-growth, temperate deciduous forest at Mont St. Hilaire, Québec, Canada. We identified 49 taxa in the seed bank, with an average of 40 species·m-2 and a median density of 1218 seeds·m-2. The most frequent seeds were species of Carex and Rubus, Diervilla lonicera, and Eupatorium rugosum, while seeds of Carex were the most numerous overall. Of the 12 species in the seed bank not found in the forest, 11 were found growing on the developed landscape surrounding this 10-km2 forest fragment. These nonforest species were numerically only a minor component of the forest seed bank. Vernal herbs were not in the seed bank, and there were only a few tree species. Variation in seed bank richness among habitats was correlated positively with canopy cover, soil moisture, and soil nutrients, but not with the seed bank density or total number of species in the aboveground vegetation. Seed bank density increased with plot soil moisture. Woody species predominated in the seed bank of plots with richer soils, deeper litter, and more closed canopies. Herbaceous species predominated in the seed bank of plots with more open canopies, more mesic water regimes, and greater species richness in the aboveground vegetation. Contrary to earlier results suggesting forest seed banks primarily include shade-intolerant species associated with canopy disturbance or secondary succession, the seed bank in this old-growth, primary forest contains many shade-tolerant forest species.Key words: seed bank, old-growth forest, primary forest, temperate deciduous forest, habitat diversity, seed dispersal.
14
Jewell, D. C. "Mexican Seed Bank". Science 231, n. 4744 (21 marzo 1986): 1355. http://dx.doi.org/10.1126/science.231.4744.1355.c.
Testo completo
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JEWELL, D. C. "Mexican Seed Bank". Science 231, n. 4744 (21 marzo 1986): 1355. http://dx.doi.org/10.1126/science.231.4744.1355-b.
Testo completo
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Hernandez, Rebecca R., Karen E. Tanner, Sophia Haji, Ingrid M. Parker, Bruce M. Pavlik e Kara A. Moore-O’Leary. "Simulated Photovoltaic Solar Panels Alter the Seed Bank Survival of Two Desert Annual Plant Species". Plants 9, n. 9 (31 agosto 2020): 1125. http://dx.doi.org/10.3390/plants9091125.
Testo completoAbstract (sommario):
Seed bank survival underpins plant population persistence but studies on seed bank trait-environment interactions are few. Changes in environmental conditions relevant to seed banks occur in desert ecosystems owing to solar energy development. We developed a conceptual model of seed bank survival to complement methodologies using in-situ seed bank packets. Using this framework, we quantified the seed bank survival of two closely related annual desert plant species, one rare (Eriophyllum mohavense) and one common (Eriophyllum wallacei), and the seed bank–environment interactions of these two species in the Mojave Desert within a system that emulates microhabitat variation associated with solar energy development. We tracked 4860 seeds buried across 540 seed packets and found, averaged across both species, that seed bank survival was 21% and 6% for the first and second growing seasons, respectively. After two growing seasons, the rare annual had a significantly greater seed bank survival (10%) than the common annual (2%). Seed bank survival across both species was significantly greater in shade (10%) microhabitats compared to runoff (5%) and control microhabitats (3%). Our study proffers insight into this early life-stage across rare and common congeners and their environmental interactions using a novel conceptual framework for seed bank survival.
17
Sanderson, Matt A., Robert Stout, Sarah Goslee, Jeff Gonet e Richard G. Smith. "Soil seed bank community structure of pastures and hayfields on an organic farm". Canadian Journal of Plant Science 94, n. 4 (maggio 2014): 621–31. http://dx.doi.org/10.4141/cjps2013-288.
Testo completoAbstract (sommario):
Sanderson, M. A., Stout, R., Goslee, S., Gonet, J. and Smith, R. G. 2014. Soil seed bank community structure of pastures and hayfields on an organic farm. Can. J. Plant Sci. 94: 621–631. Understanding the composition of seed banks in pasture soils would help farmers anticipate and manage for weed problems. We characterized the soil seed bank in eight pastures and hayfields [two alfalfa (Medicago sativa L.) and two predominantly grass hayfields; two recently established and two permanent pastures] within an organic dairy farm in southeastern New Hampshire. Seed banks were sampled in the upper 5 cm of soil in each field at a point scale in 2007 and 2010. In 2010, the seed bank was characterized at the field scale by taking soil samples on six 52-m transects in each field. Seed banks sampled at the field scale in 2010 contained 66 plant species. The total number of seeds in the seed bank ranged from 1560 m−2 in grass hayfields in autumn to more than 20 000 m−2 in alfalfa hayfields in summer. Annual forbs dominated the seed bank of alfalfa fields and recently established pastures, whereas perennial graminoids dominated in one grass hayfield and the permanent pastures. These results suggest that management history affects soil seed bank composition and abundance, and these effects should be considered before implementing management practices that could stimulate recruitment from the seed bank.
18
Rose, R. J. "The effects of hybridization on the small-scale variation in seed-bank composition of a rare plant species, Erica ciliaris L." Seed Science Research 17, n. 3 (settembre 2007): 201–10. http://dx.doi.org/10.1017/s0960258507782855.
Testo completoAbstract (sommario):
AbstractThe size and composition of the seed bank of a rare species (Erica ciliaris L.) was analysed. E. ciliaris hybridizes with a common relative in southern England (Erica tetralix). The seed banks of these co-occurring species were measured at a number of sites with a range of vegetation types and different management histories. Additional sets of samples were taken from forestry plantations on former heathland sites, where these species were known to occur. Relatively few hybrid seedlings were found in any of the seed-bank samples, even though their vegetative abundance within the sampling areas was equal to that of the pure plants. However, the abundance in the vegetation of the two pure species was reflected in the seed-bank size on each of the vegetation types, both with and without burning management. The seed banks from the forestry plantations show that the numbers of seeds of both E. tetralix and the hybrid were depleted, but that the seed bank of E. ciliaris was not significantly different from that of open heathland seed banks. The long-lived nature of the seed bank indicates that there are opportunities for habitat restoration on former heathland sites.
19
Petrulaitis, Lukas, Valerijus Rašomavičius, Domas Uogintas e Zigmantas Gudžinskas. "Soil Seed Bank of Alien and Native Cornus (Cornaceae) Taxa in Lithuania: What Determines Seed Density and Vertical Distribution in Soil?" Diversity 14, n. 6 (15 giugno 2022): 488. http://dx.doi.org/10.3390/d14060488.
Testo completoAbstract (sommario):
Soil seed banks of alien plant species are sources of propagules that play a crucial role in plant population dynamics. Studies on seed banks of woody alien species are crucial for understanding mechanisms of their encroachment on natural habitats. This study aimed to compare vertical distribution, density and composition of seed banks formed by native Cornus sanguinea subsp. sanguinea and alien C. alba, C. sericea and C. sanguinea subsp. australis in the Southern Hemiboreal zone of Europe. Five sites for each of four taxa were selected for the study, and seeds were sampled using the soil core method (400 samples in two soil layers: the upper, 0–5 cm, and the lower, 5–10 cm). Extracted seeds were tested with tetrazolium chloride stain to assess their viability. Differences in the seed banks among taxa were compared using generalised linear mixed models (GLMM). The GLMM analysis revealed significant differences in soil seed bank densities in the upper soil between the studied taxa (p < 0.001). We found that two of the alien taxa (C. alba and C. sanguinea subsp. australis) formed a much denser seed bank containing more viable seeds than the native Cornus sanguinea subsp. sanguinea. All three alien species contained more viable seeds (from 40.7% to 45.2% in the upper soil layer) than the native C. sanguinea subsp. sanguinea (19.4% in the upper and 18.2% in the lower soil layer). The cover of Cornus and habitat type had no significant effect on the density of the seed bank, according to GLMM. This study supports the hypothesis that seed banks of alien C. alba and C. sanguinea subsp. australis are denser than those of native C. sanguinea subsp. sanguinea. Furthermore, the seed bank of alien taxa contained more viable seeds than the seed bank of C. sanguinea subsp. sanguinea. Results of this study contribute to the understanding of the invasiveness of alien Cornus taxa.
20
Morgan, P., e L. F. Neuenschwander. "Seed-bank contributions to regeneration of shrub species after clear-cutting and burning". Canadian Journal of Botany 66, n. 1 (1 gennaio 1988): 169–72. http://dx.doi.org/10.1139/b88-026.
Testo completoAbstract (sommario):
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.
21
Jarvis, JC, SA McKenna e MA Rahseed. "Seagrass seed bank spatial structure and function following a large-scale decline". Marine Ecology Progress Series 665 (29 aprile 2021): 75–87. http://dx.doi.org/10.3354/meps13668.
Testo completoAbstract (sommario):
We examined the spatial structure (distribution, density) and function (viability) of the seagrass sediment seed bank, the storage of viable propagules (e.g. seeds, tubers, diaspores) in the sediment over time,in the northern Great Barrier Reef World Heritage Area in Cairns, Queensland, following a large-scale decline in seagrass area. A spatially explicit seagrass seed bank analysis was paired with a long-term annual assessment of seagrass distribution to assess seed bank spatial patterns and their relationship with the recovery and presence of seagrass, and water depth. Four years post-decline, the seed bank contained Zostera muelleri, Halodule uninervis, Halophila ovalis and Cymodocea serrulata seeds. Seed banks reflected adjacent meadow community composition; however, the density of seeds for all recorded species was significantly lower than analogous seagrass populations, indicating a reduction in the capacity for recovery from the seed bank. A spatial structure existed in both the total (viable + non-viable) and viable seed bank, and distance between seed clusters ranged from 50-550 m depending on species and seed type. Observed patterns in clustering may be explained by variation in water depth and the past distribution of seagrass in these meadows. These results demonstrate that the distribution of seagrass seeds within the seed bank, which directly influences the natural recovery of seagrass communities, is not uniform across species and may result in patchy recovery of the meadows. Therefore, the resilience provided by the seed bank in seagrass communities should not be viewed as a static level of insurance for the entire meadow, but rather as dynamic and species-specific, with variability over both space and time.
22
Simard, Marie-Josée, Sébastien Rouane e Gilles D. Leroux. "Herbicide Rate, Glyphosate/Glufosinate Sequence and Corn/Soybean Rotation Effects on Weed Seed Banks". Weed Science 59, n. 3 (settembre 2011): 398–403. http://dx.doi.org/10.1614/ws-d-10-00162.1.
Testo completoAbstract (sommario):
The effect of herbicide rates on weed control and crop yield is the subject of countless and ongoing research projects. Weed seed banks receive very little attention in comparison. The seed bank resulting from 3 yr (2006 to 2008) of single herbicide rates in a cropping system where glyphosate/glufosinate and corn/soybean were rotated or not was evaluated in a field located in St-Augustin-de-Desmaures, Québec, Canada. Field plots under conventional tillage were seeded in corn every year, or corn and soybean (1 yr). These plots received the same herbicide every year or various glyphosate/glufosinate 3-yr sequences. Subplots were sprayed with a single POST application of the recommended rate of glyphosate (900 g ae ha−1) or glufosinate (500 g ai ha−1) or lower rates. Subplots received the same full (1.0×, recommended) or reduced (0.5×, 0.75×) rate every year. After crop harvest in 2008, soil cores were extracted and the weed seed bank was evaluated. Including soybean in the cropping system resulted in lower seed banks compared to those under continuous corn cropping. Including glufosinate in a glyphosate herbicide sequence increased weed seed banks due to the lower efficacy of the glufosinate rates tested at reducing the seed bank of annual grasses. Higher herbicide rates translated into lower seed banks, up to a certain rate. After 3 yr, the lowest seed bank (full glyphosate rates every year) still had 4,339 ± 836 seeds m−2and was higher than the initial seed bank (2,826 ± 724 seeds m−2).
23
Allen, P. S., S. E. Meyer e J. Beckstead. "Predictive model for soil seedbank outcomes in the Pyrenophora semeniperda–Bromus tectorum pathosystem". Plant Protection Science 49, Special Issue (19 novembre 2013): S21—S23. http://dx.doi.org/10.17221/36/2013-pps.
Testo completoAbstract (sommario):
Pyrenophora semeniperda is abundant in soil seed banks of Bromus tectorum, where it kills a fraction of seeds throughout the year. The pathogen engages in a race with host seeds for endosperm resources; the pathogen success is negatively correlated with seed germination speed. We developed a deterministic model to predict pathosystem outcomes (seed death versus seed escape), using seed bank data from 80 sites collected over a 13-year period. The response variable (killed seeds in the spring seed bank) was regressed on multiple predictor variables (pathogen and host densities at seed dispersal, amount and timing of precipitation). Increased mortality was associated with high seed rain, high pathogen density, and low autumn precipitation. On xeric sites, a positive feedback loop between pathogen and host is created by a large carryover seed bank containing secondarily dormant seeds vulnerable to fungal attack and results in higher inoculum loads at seed dispersal the following year.
24
Chambers, Jeanne C. "Seed and vegetation dynamics in an alpine herb field: effects of disturbance type". Canadian Journal of Botany 71, n. 3 (1 marzo 1993): 471–85. http://dx.doi.org/10.1139/b93-052.
Testo completoAbstract (sommario):
Relationships among the aboveground vegetation, seed rain, and seed bank were examined on a late seral herb field characterized by pocket gopher disturbance and on an early seral gravel borrow that had been severely disturbed 35 years ago on the Beartooth Plateau, Montana. Aboveground vegetation cover was assessed by species in twelve 5-m2 plots. Seed rain was sampled during the 1988, 1989, and 1990 growing seasons with pitfall traps, and the soil seed bank was sampled in fall 1989, spring 1990, and fall 1990. The seed rain (filled seeds) on the borrow area ranged from 7730 to 14 009 seeds/m2 and was higher than that found on other alpine sites; that on the Geum turf ranged from 3375 to 6179 seeds/m2 and was similar to that for other alpine sites. Although highly variable among dates on the borrow area, the seed banks were similar to those of comparable alpine sites. Seed bank density ranged from 1980 to 6003 seeds/m2 on the borrow area and from 3202 to 4647 seeds/m2 on the Geum turf area. The Geum turf area had higher vegetation cover than the borrow area (87 vs. 25%) and higher numbers of species in the aboveground vegetation, seed rain, and seed bank. Relationships among the aboveground vegetation, seed rain, and seed bank were largely determined by the disturbance characteristics of the different sites and the life-history strategies of the dominant species. Medium-lived species, primarily grasses, with high production of small and compact seeds had colonized the borrow area. Despite establishment of other species, 35 years after disturbance the medium-lived species still dominated the aboveground vegetation, seed rain, and seed bank. Species abundances in the three different components were all highly correlated. In contrast, on the Geum turf area there were no correlations among the aboveground vegetation, seed rain, or seed bank. Long-lived forbs that produced low numbers of relatively large seeds dominated the aboveground vegetation and persisted on the area primarily in the vegetative state. The same medium-lived species that dominated the borrow area had the highest abundance in the seed rain on the Geum turf area and appeared to persist by colonizing small-scale disturbances caused by gopher burrowing. Short-lived species with small, long-lived seeds existed on the site primarily through a highly persistent seed bank. The relationships among the aboveground vegetation, seed rain, and seed bank on the Geum turf and borrow areas are compared with those observed for more temperate systems following disturbance. Key words: alpine, herb field, Geum turf, disturbance, vegetation cover, seed rain, seed bank, colonization, establishment, succession.
25
Wang, Ning, Ju-Ying Jiao, Yan-Feng Jia e Dong-Li Wang. "Seed persistence in the soil on eroded slopes in the hilly-gullied Loess Plateau region, China". Seed Science Research 21, n. 4 (5 agosto 2011): 295–304. http://dx.doi.org/10.1017/s0960258511000195.
Testo completoAbstract (sommario):
AbstractThe soil seed-bank is an important component of vegetation dynamics. Its presence affects both ecosystem resistance and resilience. A persistent seed-bank is especially important in disturbed habitats and harsh environments. In the hilly-gullied Loess Plateau region, serious soil erosion causes decreases in soil water capacity and constrains vegetation recolonization. A stable and long-term persistent soil seed-bank is necessary for natural vegetation recolonization. We used an integrated measure of the depth distribution of seeds in the soil and the seasonal dynamics of soil seed-banks to analyse the persistence of seeds in soil and to investigate the correlation of seed longevity with seed size/shape and the species' life history. The results showed a significant tendency for small seeds and seeds of annuals/biennials to persist longer in soil than large seeds and seeds of perennials. However, seed shape was not related to persistence. The main dominant speciesArtemisia scoparia, Lespedeza davurica, Heteropappus altaicus, Stipa bungeana, Artemisia gmelinii, and Bothriochloa ischaemun in the different successional stages in this region can form a persistent and stable soil seed-bank. The pioneer species A. scoparia is especially significant because it can form a large, long-term, persistent seed-bank. These species can play a role in the recolonization of the eroded abandoned slope lands by vegetation.
26
Álvarez-Espino, Ricardo, Héctor Godínez-Álvarez e Rodolfo De la Torre-Almaráz. "Seed banking in the columnar cactusStenocereus stellatus: distribution, density and longevity of seeds". Seed Science Research 24, n. 4 (17 ottobre 2014): 315–20. http://dx.doi.org/10.1017/s0960258514000324.
Testo completoAbstract (sommario):
AbstractThe soil seed bank is the reserve of viable seeds found in the soil. This reserve contributes to plant population persistence in unpredictable environments; thus, determining its presence is basic to understanding recruitment patterns and population dynamics. Studies of soil seed banks in the Cactaceae are scarce, although these plants are ecologically dominant in American arid and semi-arid environments. Most studies have inferred the presence of seed banks by analysing morphological seed traits or germination of seeds stored in the laboratory for different periods of time. Few studies have determined their presence through evaluation of distribution, density and longevity of seeds in the field. To fill this information gap, we determined the existence of, and studied, the soil seed bank ofStenocereus stellatus, a columnar cactus endemic to central Mexico. This study reports the evaluation of these characteristics in the field and discusses whether this species forms a soil seed bank. We found a higher number of seeds under shrubs than in areas lacking vegetation. Recently dispersed seeds did not germinate because they have primary dormancy. This dormancy was broken after 6 months of burial in the soil. Seeds buried for 10 months entered secondary dormancy and they were not viable at 24 months, probably because of pathogen attack. Considering dormancy and seed longevity, we suggest thatS. stellatushas the potential to form a short-term persistent seed bank. However, this should be confirmed by conducting studies on otherS. stellatuspopulations throughout their geographical distribution.
27
Traba, Juan, Francisco M. Azcárate e Begoña Peco. "From what depth do seeds emerge? A soil seed bank experiment with Mediterranean grassland species". Seed Science Research 14, n. 3 (settembre 2004): 297–303. http://dx.doi.org/10.1079/ssr2004179.
Testo completoAbstract (sommario):
Seed germination and emergence are influenced by the position of seeds in the soil bank profile. Mediterranean grasslands are heavily dependent on seed banks, as these systems are mainly composed of annual species. Seed bank germination experiments in a greenhouse were conducted to analyse the role played by burial depth on seed bank dynamics in annual Mediterranean grasslands. Specifically, they addressed two objectives: (1) to assess the ability of seeds in the shallow layer of the soil bank to emerge when they are buried at different depths, and (2) to ascertain the ability of seeds from deep layers to germinate and emerge to the surface. The study also produced a depth profile of species and seeds. The results show that: (1) all species (100%) and the majority of viable seeds (98.9%) are situated in the first centimetre, with a significant fall in the number of species and seeds in the soil bank as depth increases; (2) for the majority of species (92%) and seeds (85.4%) in the shallow bank, the emergence percentage declines significantly with burial depth; and (3) seeds that are present in deep layers need to rise to the surface in order to produce seedlings. In conclusion, the function of the seed bank in Mediterranean grasslands depends on the number of species and seeds in it, but also on the seed position in the profile and vertical movements that enable them to reach the surface.
28
Baughman, Owen W., e Susan E. Meyer. "Is Pyrenophora semeniperda the Cause of Downy Brome (Bromus tectorum) Die-offs?" Invasive Plant Science and Management 6, n. 1 (marzo 2013): 105–11. http://dx.doi.org/10.1614/ipsm-d-12-00043.1.
Testo completoAbstract (sommario):
AbstractDowny brome (cheatgrass) is a highly successful, exotic, winter annual invader in semi-arid western North America, forming near-monocultures across many landscapes. A frequent but poorly understood phenomenon in these heavily invaded areas is periodic ‘die-off’ or complete stand failure. The fungal pathogen Pyrenophora semeniperda is abundant in cheatgrass seed banks and causes high mortality. To determine whether this pathogen could be responsible for stand failure, we quantified late spring seed banks in die-off areas and adjacent cheatgrass stands at nine sites. Seed bank analysis showed that this pathogen was not a die-off causal agent at those sites. We determined that seed bank sampling and litter data could be used to estimate time since die-off. Seed bank patterns in our recent die-offs indicated that the die-off causal agent does not significantly impact seeds in the persistent seed bank.
29
Abella, Scott R., Judith D. Springer e W. Wallace Covington. "Seed banks of an Arizona Pinus ponderosa landscape: responses to environmental gradients and fire cues". Canadian Journal of Forest Research 37, n. 3 (marzo 2007): 552–67. http://dx.doi.org/10.1139/x06-255.
Testo completoAbstract (sommario):
We measured soil seed banks in 102 plots within a 110 000 ha Arizona Pinus ponderosa landscape, determined seed-bank responses to fire cues and tree canopy types (open or densely treed patches), compared seed-bank composition among ecosystem types, and assessed the utility of seed banks for ecological restoration. Liquid smoke was associated with increased community-level emergence from seed banks in greenhouse experiments, whereas heating to 100 °C had minimal effect and charred P. ponderosa wood decreased emergence. We detected 103 species in seed-bank samples and 280 species in aboveground vegetation. Erigeron divergens was the commonest seed-bank species; with the exception of Gnaphalium exilifolium , species detected in seed banks also occurred above ground. Although a dry, sandy-textured black-cinder ecosystem exhibited the greatest seed density, seed-bank composition was more ecosystem-specific than was seed density. Native graminoids (e.g., Carex geophila and Muhlenbergia montana ) were common in seed banks, whereas perennial forbs were sparse, particularly under dense tree canopies. Our results suggest that (i) smoke may increase emergence from seed banks in these forests, (ii) seed banks can assist establishment of major graminoids but not forbs during ecological restoration, and (iii) seed-bank composition is partly ecosystem-specific across the landscape.
30
Jankowska-Błaszczuk, Małgorzata. "Zróżnicowanie banków nasion w naturalnie i antropogenicznie przekształconych zbiorowiskach leśnych [Diversity of soil seed banks in natural and man-modified forest communities]". Monographiae Botanicae 88 (2014): 1–147. http://dx.doi.org/10.5586/mb.2000.002.
Testo completoAbstract (sommario):
The objective of the study was to reveal diversity in species composition and size of soil seed banks derived from forest communities undergoing different intensity of human impact as well as to show the seed bank strategy as an adaptation of species to many kinds of disturbances occurring in natural deciduous forests. On the basis of the study of soil seed bank in natural, stabilised deciduous forest communities in Białowieża National Park and taking into account data from literature it was found that: (1) Densities of seed banks of fertile, undisturbed deciduous forest vary from three to eight thousand seeds per one m<sup>2</sup>. The majority of these seeds (60–80%)come from the herb layer. Persistance of such banks do not exceed a few years. Species which arę dominant in seed bank of such forest are characterized by mean light requirements. The impulses which break their secondary dormancy arę slight disturbances in the herb layer. (2) Species structure of seed bank derived from such forest does not reflect floristic composition of the herb layer because this layer is dominated by species whose survival strategy is connected with vegetative propagation. (3) In seed banks of even very stable forest communities there are species which are absent from the herb layer of the forest. The species need light gaps in trees canopy for establishment. They are very light demanding and persistent in soil. Percentage of these species in soil seed banks grows with the intensity of human impact on forest communities. These species dominate also in seed banks of relatively natural forests but small and surrounded by meadows and fields. Seedlings of these species occur spontanously during the first phase of regeneration of forest gaps. After the canopy close-up, the species disappear from cover vegetation but their numerous and very persistant seeds wait in soil seed bank for the next disturbance.
31
Plue, J., J. L. Dupouey, K. Verheyen e M. Hermy. "Forest seed banks along an intensity gradient of ancient agriculture". Seed Science Research 19, n. 2 (giugno 2009): 103–14. http://dx.doi.org/10.1017/s0960258509306662.
Testo completoAbstract (sommario):
AbstractRecently, forest seed banks were proven to not only reflect former (decades-old) but also ancient (centuries-old) land use. Yet, as land-use intensity determines the magnitude of seed-bank changes in recent forests, this study aims to identify whether an ancient land-use gradient would also be reflected in the seed bank. On a forested 1600-year-old archaeological site, five different land-use intensities were mapped and sampled. Apart from seed density, species richness and composition, functional seed-bank types, defined by nine seed-bank-related plant traits, were related to the land-use intensity gradient. The land-use gradient from gardens to undisturbed sites was still clearly reflected in the soil seed bank. Six emergent functional seed-bank types, characterized by specific plant traits, changed significantly in abundance, parallel to the land-use gradient. In particular, dispersal agent (and related traits) proved an important explanatory trait of present (functional) seed-bank patterns. Poor dispersers (large and heavy seeds) were not found in the intensively used areas, contrary to animal-dispersed species. Wind-dispersers may have been inhibited in the extension of their distribution by recruitment bottlenecks (low seed production) and/or competitive exclusion. Additionally, the agricultural land-use probably introduced ruderal species into the seed bank of the most intensively used areas, yielding a simultaneous increase in vegetation–seed-bank dissimilarity with land-use intensity, eliminating present vegetation as a driver behind the differences over the seed-bank gradient. We conclude by arguing how coppice-with-standards management possibly maintained the seed-bank gradient.
32
Villiers, A. J. De, M. W. Van Rooyen e G. K. Theron. "Seed bank classification of the Strandveld Succulent Karoo, South Africa". Seed Science Research 12, n. 1 (marzo 2002): 57–67. http://dx.doi.org/10.1079/ssr200198.
Testo completoAbstract (sommario):
Laboratory characteristics of seeds of 37 species (41 seed types) from the Strandveld Succulent Karoo were used to predict seed bank types according to a modified key of ). Five seed bank strategies were recognized for this vegetation type, i.e. two with transient and three with persistent seed bank strategies. Of the 37 species investigated, 32% (all perennial species) had transient seed bank strategies, while 68% had persistent seed bank strategies. Seed dispersal of these 37 species was mainly anemochorous, although antitelechoric elements such as myxospermy, hygrochasy, heterodiaspory and synaptospermy were found among these species. The seed bank alone will not be sufficient to restore the vegetation of damaged land in the Strandveld Succulent Karoo, since many of the dominant species in the vegetation do not produce persistent seed banks. Many of these species may, however, be dispersed by wind into revegetation areas from surrounding vegetation. Topsoil replacement, seeding and transplanting of selected species will be essential for the successful revegetation of mined areas in this part of Namaqualand.
33
Wódkiewicz, Maciej, e Anna Justyna Kwiatkowska-Falińska. "Similarity between seed bank and herb layer in a natural deciduous temperate lowland forest". Acta Societatis Botanicorum Poloniae 79, n. 2 (2011): 157–66. http://dx.doi.org/10.5586/asbp.2010.021.
Testo completoAbstract (sommario):
Forest seed banks mostly studied in managed forests proved to be small, species poor and not reflecting aboveground species composition. Yet studies conducted in undisturbed communities indicate a different seed bank characteristic. Therefore we aimed at describing soil seed bank in an undisturbed forest in a remnant of European lowland temperate forests, the Białowieża Forest. We compared similarity between the herb layer and seed bank, similarity of seed bank between different patches, and dominance structure of species in the herb layer and in the seed bank of two related oak-hornbeam communities. We report relatively high values of Sorensen species similarity index between herb layer and seed bank of both patches. This suggests higher species similarity of the herb layer and soil seed bank in natural, unmanaged forests represented by both plots than in fragmented communities influenced by man. Although there was a set of core seed bank species present at both plots, yielding high Sorensen species similarity index values, considerable differences between plots in seed bank size and dominance structure of species were found, indicating spatial variability of studied seed bank generated by edaphic conditions. Dominance structure of species in the herb layer was not reflected in the underlying seed bank. This stresses, that natural forest regeneration cannot rely only on the seed bank, although some forest species are capable of forming soil seed banks. While forest seed banks may not reflect vegetation composition of past successional stages, they may inform on history and land use of a specific plot.
34
Qi, Meiqin, e John B. Scarratt. "Effect of harvesting method on seed bank dynamics in a boreal mixedwood forest in northwestern Ontario". Canadian Journal of Botany 76, n. 5 (1 maggio 1998): 872–83. http://dx.doi.org/10.1139/b98-061.
Testo completoAbstract (sommario):
The effects of harvesting on seed bank dynamics in a boreal mixedwood forest were studied on replicated 10-ha treatment blocks harvested by different clear-cutting or partial-cutting systems in the fall of 1993. From 1994 to 1995 we monitored seed rain, soil seed banks, and seasonal changes in species composition in understory vegetation and seed banks in all harvest blocks plus three uncut controls. No persistent conifers were found in the soil seed banks of any treatment. The number of seeds of other species generally decreased with soil depth in all treatments, with the lower layer of organic soil yielding the highest numbers of seedlings. Many seeds of sedges and some herbs were found in the upper mineral soil horizon, indicating significant longevity. While disturbance by harvesting operations altered the distribution of seeds in the soil profile, harvesting method had little effect on the total number of species present in post-harvest seed banks or understory vegetation. There were no differences in seasonal compositional changes between treatments. Seed rain monitoring indicated that few conifer seeds were added to the seed bank. Betula papyrifera Marsh. was the dominant tree species in seed rain in the partial cutting treatments. However, in the second post-harvest year on clear cut sites sedges and grasses increased from less than 1 to 14% of seed rain. The results suggest that predominantly hardwood stands with prolific understory vegetation will initially develop on the treated sites, with a variable, but depleted conifer content.Key words: boreal mixedwood forest, natural regeneration, seed rain, seed bank, succession, vegetative propagation.
35
Abella, Scott R., e Judith D. Springer. "Soil seed banks in a mature coniferous forest landscape: dominance of native perennials and low spatial variability". Seed Science Research 22, n. 3 (12 giugno 2012): 207–17. http://dx.doi.org/10.1017/s0960258512000074.
Testo completoAbstract (sommario):
AbstractSoil seed banks are important to vegetation recruitment, ecosystem functioning and land management. We evaluated composition of 0–5 cm soil seed banks and relationships of seed banks with forest community types (ranging from low-elevation pinyon–juniper to high-elevation bristlecone pine), vegetation cover and environmental variables within a 40,000-ha relatively undisturbed coniferous forest landscape in Nevada, USA. We collected samples from 36 sites and used the emergence method to assay seed banks. Seed density averaged 479 seeds m− 2across sites and a total of 39 taxa were detected. Most (79%) of these taxa were perennials and 35 of 39 (90%) were native. Moreover, 62% of seed-bank taxa were in the vegetation of mature forests, an uncommon finding in studies of forest soil seed banks. Seed-bank density, species richness and composition did not display strong relationships with forest community types, vegetation cover or environmental variables. Weak relationships likely arose from the relatively uniform seed-bank density among sites, where 50% of sites had seed densities in the range of 106–282 m− 2. Results suggest that while seed banks on this landscape are not large, they provide recruitment potential for some native perennial species of mature, relatively undisturbed communities.
36
Akinola, M. Olatunde, Ken Thompson e Susan H. Hillier. "Development of soil seed banks beneath synthesized meadow communities after seven years of climate manipulations". Seed Science Research 8, n. 4 (dicembre 1998): 493–500. http://dx.doi.org/10.1017/s0960258500004463.
Testo completoAbstract (sommario):
AbstractMeadow microcosms were established from seed on low-fertility soil of known seed bank composition, and subjected to manipulations of simulated grazing, cutting date, temperature and fertility for seven years. The composition and density of the seed bank was then determined in five 2-cm soil layers (0–2, 2–4, 4–6, 6–8 and 8–10 cm). The seed bank contained three distinct groups of species: species present in the original soil, sown species, and ‘others’. The seed bank was little affected by the experimental treatments, presumably because the sown species made only a small contribution to the seed bank. Nearly all the species in the original soil are known to possess persistent seed banks and had survived, although at reduced density, for seven years. Density of the most abundant species in this group, Sagina procumbens, had changed very little over seven years, confirming the well-documented longevity of the seeds of this species. Seeds of sown species made up only about a quarter of the seed bank, despite accounting for virtually all the above-ground vegetation. Of the sown meadow species, only Plantago lanceolata and Alopecurus pratensis were relatively abundant in the seed bank. These results strongly support the conclusion of other authors that most meadow species, once lost owing to the effects of fertilizers or inappropriate management, will not reestablish from the seed bank. Among species which were neither sown nor present in the original soil, the majority possessed adaptations for wind dispersal and had presumably dispersed into the experimental plots from outside. The most abundant member of this group, Betula pendula, had dispersed from a nearby tree. Density of Betula seeds declined sharply with depth, consistent with the view that seeds on the soil surface are rapidly lost, mainly through germination, but seeds that become buried survive much better. Seeds of Betula appear to be persistent but not particularly long-lived.
37
Butler, Jack, e Kara Paintner. "Rangeland Recovery Potential: Soil Seed Content and Seed Viability". UW National Parks Service Research Station Annual Reports 15 (1 gennaio 1991): 130–35. http://dx.doi.org/10.13001/uwnpsrc.1991.2993.
Testo completoAbstract (sommario):
The objectives of this project are to 1) evaluate the viable seed bank within grazed and relict pinyonÂjuniper and blackbrush/lndian ricegrass communities, 2) assess the ability of these communities to recover following a disturbance using their respective seed banks as indicators of recovery potential, and 3) address the suitability of using seed banks to monitor and predict community level composition changes in response to various intensities of grazing.
38
Goodson, J. M., A. M. Gurnell, P. G. Angold e I. P. Morrissey. "Riparian seed banks: structure, process and implications for riparian management". Progress in Physical Geography: Earth and Environment 25, n. 3 (settembre 2001): 301–25. http://dx.doi.org/10.1177/030913330102500301.
Testo completoAbstract (sommario):
After a brief description of the evolution of seed bank research, this review highlights the importance of the seed bank in understanding the character and dynamics of river margins. Through a discussion of published research on wetlands in general, the lack of research focused on riparian systems is highlighted. This is followed by an evaluation of current knowledge concerning the nature and dynamics of riparian seed banks and the factors that control the erosion, transport and deposition of riparian seeds. The paper concludes by (i) indicating the complexity of the interactions that control the riparian seed bank and that require understanding if the consequences of alterations in river flow regime and riparian management are to be fully understood and (ii) identifying some major research gaps relating to interactions between fluvial processes and riparian seed banks.
39
Lu, Juan J., Dun Y. Tan, Jerry M. Baskin e Carol C. Baskin. "Two kinds of persistent soil seed banks in an amphi-basicarpic cold-desert annual". Seed Science Research 24, n. 4 (3 settembre 2014): 293–300. http://dx.doi.org/10.1017/s0960258514000270.
Testo completoAbstract (sommario):
AbstractSeveral studies have compared seed banks of the different morphs of heteromorphic species, but none of them was on an amphi-basicarpic species. Our primary aim was to compare the relative ability of aerial and basal diaspores of an amphi-basicarpic species to form a seed bank. We compared the seed-bank dynamics of basal and aerial diaspores of three populations of the cold-desert annualCeratocarpus arenariusgrowing in the Junggar Desert in north-western China. A 2.5-year experimental garden study compared germination phenology and retention of viability in basal (a) and aerial (c and f) morphs. Aerial morphs formed a modified Thompson and Grime type III seed bank (small proportion of seeds carried over to next year) and the basal morph a modified type IV seed bank (large proportion of seeds carried over to next year). Seeds germinated only in spring, and cumulative germination percentages were f>c>a (year 1), f = c>a (year 2) and f = c = a (year 3). The relationship between length of germination period, retention of viability during burial and relative ability to form a persistent seed bank was basal morph > aerial morphs. The results of this seed-bank study onC. arenariusare in full agreement with those published previously on seed dispersal and dormancy in this species. Thus, strong additional support is provided for a high risk–low risk germination strategy in this cold-desert annual.
40
Yehnjong, Petra S., Michael S. Zavada e Chris Liu. "Characterization and ecological significance of a seed bank from the Upper Pennsylvanian Wise Formation, southwest Virginia". Acta Palaeobotanica 57, n. 2 (1 dicembre 2017): 165–75. http://dx.doi.org/10.1515/acpa-2017-0017.
Testo completoAbstract (sommario):
AbstractSoil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed longevity, which reduces the effect of environmental variability on seed germination and development. The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts. The estimated seed density of 192 seeds/m2in the Palaeozoic seed bank falls within the range of modern seed banks, but at the lower end of modern seed bank densities in a variety of habitats.
41
Brock, MA, K. Theodore e L. O'Donnell. "Seed-bank methods for Australian wetlands". Marine and Freshwater Research 45, n. 4 (1994): 483. http://dx.doi.org/10.1071/mf9940483.
Testo completoAbstract (sommario):
A sampling protocol for the assessment of seed banks in Australian temporary and permanent wetlands is presented. A simple corer design allows removal of intact samples from water depths up to 1.2 m, ensuring comparable sampling in a variety of wetland habitats. Sampling and experimental designs appropriate for answering questions about the germination of seeds from sediments under different water regimes in both the glasshouse and the field are presented. The adequacy of area sampled and of number of replications for assessment of species richness and abundance of seeds in the seed bank is considered, and a minimum number of five aggregate samples (each sample of eight cores has an area of 0.016 m2) is suggested for these wetlands. The variation between samples in this study is within the range reported for seed-bank studies in similar wetlands in North America.
42
Jakobsson, Anna, Ove Eriksson e Hans Henrik Bruun. "Local seed rain and seed bank in a species-rich grassland: effects of plant abundance and seed size". Canadian Journal of Botany 84, n. 12 (dicembre 2006): 1870–81. http://dx.doi.org/10.1139/b06-136.
Testo completoAbstract (sommario):
In this study, we examined the relationship between seed size, seed rain, and seed bank in a species-rich perennial grassland in Sweden. The seed rain was monitored by 100 seed traps placed in a 10 m × 10 m area for 1 year. The seed bank was sampled by taking 100 soil samples, each in close vicinity to a seed trap. Abundance of reproductive ramets in the area was estimated, since this is likely to affect the proportion of hit seed traps and seed bank samples. When abundance of reproductive ramets was accounted for, we found a negative relationship between seed size and proportion of hit seed bank samples, but we found no relationship between seed size and proportion of hit seed traps. We found strong positive relationships between the abundance of reproductive ramets and proportion of hit seed traps and seed bank samples. We also found strong positive relationships between abundance of reproductive ramets and abundance of seeds in the seed rain and the seed bank, but no relationship between seed size and abundance of seeds in the seed rain or the seed bank. We discuss these results in the context of theory suggesting that large-seeded and small-seeded species may coexist because of a trade-off between colonization and competitive abilities, where smaller-seeded species are able to reach more sites than seeds of larger-seeded species, because they are more numerous and (or) better dispersed.
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Campos, João Batista, e Maria Conceição de Souza. "Potencial for natural forest regeneration from seed bank in an upper Paraná river floodplain, Brazil". Brazilian Archives of Biology and Technology 46, n. 4 (dicembre 2003): 625–39. http://dx.doi.org/10.1590/s1516-89132003000400018.
Testo completoAbstract (sommario):
The historical process of deforestation was analyzed to evaluate the regeneration potential of forests from soil seed bank of Porto Rico island (53° 15'W and 22° 45'S) in the upper Paraná river floodplain. Remnant forest fragments were identified and measured and the structure of arboreous vegetation and the composition of the seed bank of the forests and grassland of the island were evaluated. Results showed a fast process of deforestation with critical levels of forest: the remaining twice fragments represented only 5.98% of the total surface of the island. Disturbance by cattle raised on the island continuously degraded the fragments (backward succession), while expansion of areas with pasture favored severe impoverishment of the seed banks flora. The latter factor, soil compaction, and characteristics of seeds of existing arboreous species in the bank suggested that the immediate reestablishment of vegetation was more conditioned to introduction processes of seeds (by rain and ''flood seed'') than by stock of seeds in the bank.
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Andrews, TS, RDB Whalley e CE Jones. "Seed production and seedling emergence of Giant Parramatta grass on the north coast of New South Wales". Australian Journal of Experimental Agriculture 36, n. 3 (1996): 299. http://dx.doi.org/10.1071/ea9960299.
Testo completoAbstract (sommario):
Inputs and losses from Giant Parramatta grass [GPG, Sporobolus indicus (L.) R. Br. var. major (Buse) Baaijens] soil seed banks were quantified on the North Coast of New South Wales. Monthly potential seed production and actual seed fall was estimated at Valla during 1991-92. Total potential production was >668 000 seeds/m2 for the season, while seed fall was >146000 seeds/m2. Seed fall >10000 seeds/m2.month was recorded from January until May, with further seed falls recorded in June and July. The impact of seed production on seed banks was assessed by estimating seed banks in the seed production quadrats before and after seed fall. Seed banks in 4 of the 6 sites decreased in year 2, although seed numbers at 1 damp site increased markedly. Defoliation from mid-December until February, April or June prevented seed production, reducing seed banks by 34% over 7 months. Seed banks in undefoliated plots increased by 3300 seeds/m2, although seed fall was estimated at >114 000 seeds/m2. Emergence of GPG seedlings from artificially established and naturally occurring, persistent seed banks was recorded for 3 years from bare and vegetated treatment plots. Sown seeds showed high levels of innate dormancy and only 4% of seeds emerged when sown immediately after collection. Longer storage of seeds after collection resulted in more seedlings emerging. Estimates of persistent seed banks ranged from 1650 to about 21260 seeds/m2. Most seedlings emerged in spring or autumn and this was correlated with rainfall but not with ambient temperatures. Rates of seed bank decline in both bare and vegetated treatment plots was estimated by fitting exponential decay curves to seed bank estimates. Assuming no further seed inputs, it was estimated that it would take about 3 and 5 years, respectively, for seed banks to decline to 150 seeds/m2 in bare and vegetated treatments.
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Tenner, Clare. "The Millennium Seed Bank". Curtis's Botanical Magazine 21, n. 1 (febbraio 2004): 91–94. http://dx.doi.org/10.1111/j.1467-8748.2004.00419.x.
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SUN, M. "Response: Mexican Seed Bank". Science 231, n. 4744 (21 marzo 1986): 1355. http://dx.doi.org/10.1126/science.231.4744.1355-c.
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Buhler, Douglas D., Robert G. Hartzler e Frank Forcella. "Weed Seed Bank Dynamics". Journal of Crop Production 1, n. 1 (8 ottobre 1997): 145–68. http://dx.doi.org/10.1300/j144v01n01_07.
Testo completo
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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, n. 10 (1 ottobre 2004): 1468–80. http://dx.doi.org/10.1139/b04-108.
Testo completoAbstract (sommario):
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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Ong, Glendon Hong Ming, Samantha Lai, Siti Maryam Yaakub e Peter Todd. "Depauperate seed banks in urban tropical seagrass meadows". Marine and Freshwater Research 71, n. 8 (2020): 935. http://dx.doi.org/10.1071/mf19204.
Testo completoAbstract (sommario):
Seagrasses need to be resilient if they are to persist in the long term. Being able to build up a dormant seed bank in sediments is a key strategy that some species employ to regenerate from large-scale degradation. Much of the research on seed banks has focussed on temperate species, and little is known regarding the status of seed banks in tropical meadows. In the present study, we examined the seed bank status of three common seagrass species at six sites in Singapore and attempted to identify potential drivers of seed abundance. Our results indicated depauperate seed banks with few species setting viable seed and low seed densities. Halophila ovalis seeds were found at four sites and Halodule uninervis seeds at two sites, but Cymodocea rotundata seeds were absent from all six sites. Whereas H. ovalis seed viability ranged from 20% to 68.8%, none of the H. uninervis seeds was viable. Halophila ovalis seed densities (33–334m–2) were much higher than those of H. uninervis (9–21m–2). Of the variables examined, only H. ovalis cover was positively correlated with the number of seeds. Our study has highlighted the vulnerability of seagrass meadows in Singapore’s urban waters to future disturbances.
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Campbell, Monica L., Peter J. Clarke e David A. Keith. "Seed traits and seed bank longevity of wet sclerophyll forest shrubs". Australian Journal of Botany 60, n. 2 (2012): 96. http://dx.doi.org/10.1071/bt11261.
Testo completoAbstract (sommario):
In wet sclerophyll forests seedling recruitment either occurs after intermittent fire events or continuously during intervals between fires in gaps created by small-scale disturbances. The dormancy and dispersal characteristics of seeds will influence how plant species exploit these contrasting recruitment opportunities. For example, long-lived seed banks may be crucial for persistence of species that are unable to recruit during intervals between fires if the length of fire intervals exceeds the life span of standing plants (senescence risk). To better understand mechanisms of population persistence during prolonged absence of fire in montane wet sclerophyll forests, we studied seed bank dynamics in four understorey species. We chose two species thought to have fire event-driven recruitment, Banksia integrifolia subsp. monticola (Proteaceae) and Goodia lotifolia (Fabaceae), and two species that are thought to have canopy gap-phase recruitment, Trochocarpa laurina (Ericaceae) and Tasmannia stipitata (Winteraceae). We measured seed rain, seed bank density and used seeds buried in nylon mesh bags to estimate rates of seed decay in the soil over time. All species produced a substantial seed crop on an annual basis. The annual seed crop in three species (G. lotifolia, T. stipitata and T. laurina) was released in a dormant state and developed a persistent seed bank, while one species (B. integrifolia) lacked dormancy and rapidly germinated under laboratory and field conditions. Seed bank characteristics of G. lotifolia appear to promote episodic recruitment after large landscape-scale fires, those of B. integrifolia appear to promote more continuous recruitment in response to smaller fires and other disturbances that avoid widespread mortality of established plants, while seed bank characteristics of T. stipitata and T. laurina may facilitate both episodic and continuous recruitment under respective types of disturbance. The four species appeared to have varied vulnerabilities and mechanisms for reducing immaturity risk and senescence risk to persistence of their populations under recurrent disturbance. Dormancy, seed bank longevity and seed rain are likely to be useful syndromes for predicting the response of wet sclerophyll forest understorey species to changed disturbance regimes.