scholarly journals Changes of soil seed bank by seed density, number of taxa and composition for seven years

2013 ◽  
Vol 39 (1) ◽  
pp. 56-61
Author(s):  
Keitaro YAMASE ◽  
Hiroaki SEKIOKA ◽  
Chikage TODO
2000 ◽  
Vol 78 (5) ◽  
pp. 577-582 ◽  
Author(s):  
Catherine Zabinski ◽  
Todd Wojtowicz ◽  
David Cole

We investigated the soil seed bank in a subalpine ecosystem with patchy disturbance from camping. Soil cores were collected from three site types, heavily impacted, lightly impacted, and undisturbed, that differed in area of bare ground and depth of surface organic matter. We hypothesized that the density and composition of the seed bank would vary with depth of surface organic matter and distance from established vegetation. Seedling emergence was determined in the greenhouse. Seed density was significantly lower on disturbed sites, averaging 441 seeds/m2 on heavily impacted sites, 1495 seeds/m2 on lightly impacted sites, and 4188 seeds/m2 on undisturbed sites. Seed density declined exponentially with distance from established vegetation and increased with depth of surface organic matter. The number of species present did not vary across site types, but 10 species that occurred on lightly impacted and undisturbed sites were not present on heavily impacted sites. We concluded that disturbance that causes removal of surface organic matter can affect natural revegetation by lowering the density of propagules and affecting the species represented in the seed bank.Key words: seed bank, subalpine, patchy disturbance, recreation impacts.


2004 ◽  
Vol 82 (12) ◽  
pp. 1809-1816 ◽  
Author(s):  
Luis Marone ◽  
Víctor R Cueto ◽  
Fernando A Milesi ◽  
Javier Lopez de Casenave

We assessed soil seed bank composition and size over several microhabitats of two habitats of the central Monte Desert of Argentina (open Prosopis woodland and Larrea shrubland) to analyse differences among them. Seed densities were similar to those already reported for other deserts, but we found consistent differences in seed composition among microhabitats. Whereas grass seeds (e.g., Aristida, Pappophorum, Neobouteloua, Trichloris, Digitaria) prevailed in natural depressions of open areas, forb seeds (e.g., Phacelia, Lappula, Descurainia, Plantago, Chenopodium) were more abundant under trees. The comparison of seed production during primary dispersal (i.e., seed rain) with seed density on the ground at the end of dispersal indicated that most forb seeds entered the habitat through the micro habitats located beneath the canopy of trees and tall shrubs, and remained there after redistribution. Most grass seeds, by contrast, entered it through bare-soil and under-grass microhabitats, and reached more even distributions after secondary dispersal, especially because of dramatic losses in bare soil. Patterns of plant recruitment and seed dynamics in specific microhabitats were better understood when differences of soil seed bank composition, but not of total seed density, were taken into account.Key words: Monte Desert, seed dispersal, seed predation, seed production, seeds.


Flora ◽  
2013 ◽  
Vol 208 (7) ◽  
pp. 445-452 ◽  
Author(s):  
Danielle Melo dos Santos ◽  
Kleber Andrade da Silva ◽  
Ulysses Paulino de Albuquerque ◽  
Josiene Maria Falcão Fraga dos Santos ◽  
Clarissa Gomes Reis Lopes ◽  
...  

2019 ◽  
Vol 13 (2) ◽  
pp. 177-184
Author(s):  
Bobbymoore Konsam ◽  
Shyam S Phartyal ◽  
Nagendra P Todaria

Abstract Aims To explain how plant community copes with a recurring anthropogenic forest fire in Himalayan Chir pine forest, it is important to understand their postfire regeneration strategies. The primary aim of the study was to know: (i) how fire impact soil seed bank composition and (ii) how much soil seed bank composition differs with standing vegetation after the forest fire. Methods Soil samples were collected from burned and adjoining unburned sites in blocks using three layers down to 9 cm depth immediately after a forest fire and incubated in the net-house for seedling emergence. Same sites were revisited during late monsoon/early autumn season to know the species composition of standing vegetation recovered after a forest fire. Important Findings Soil contained viable seeds of >70 species. The average seed bank density was 8417 and 14 217 seeds/m2 in the burned and unburned site, respectively. In both sites, it decreased with increasing soil depth. Overall fire had no significant impact on seed density; however, taking individual layers into consideration, fire had a significant impact on seed density only in the uppermost soil layer. The species richness of soil seed bank and standing vegetation was 73 and 100, respectively (with 35 shared species), resulting in a similarity of about 40%. In contrast, >80% species in soil seed bank was found similar between burned and unburned sites. Further, there were no significant differences in species richness of standing vegetation in burned (87 spp.) and unburned (78 spp.) sites. Our results showed that fire had an insignificant impact on soil seed bank composition and restoration potential of a plant species from seeds. The understory herb and shrub plant community’s ability to form a fire-resistant viable soil seed bank and capable to recover in the postfire rainy season, explains how they reduce the risk of recurring fire damage in maintaining their population.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1890
Author(s):  
Yanyan Lv ◽  
Menghong Shen ◽  
Baoping Meng ◽  
Huifang Zhang ◽  
Yi Sun ◽  
...  

The asymmetric response of productivity to precipitation was recently proposed as an early warning signal for the shifts in temperate grassland function in China. It was hypothesized that the asymmetry was influenced by the increased growth of the newly emerged seedlings from the soil seed bank. Therefore, the seed density in the soil seed bank and the similarity between species composition of the vegetation and the soil seed bank should be maximized where asymmetry was maximized. However, this knowledge was still limited and unconfirmed. In this study, the desert steppe, typical steppe and the transition zone between them (with the highest asymmetry) were selected for studying the similarity index in both 2018 (dry year) and 2019 (wet year). Plant species composition was monitored in situ using an unmanned aerial vehicle. Soil seed bank samples were collected, and the seed bank density and species composition were then examined and identified in the laboratory. Results showed that: (1) The variation in vegetation species richness between the two years was the highest (41%) in the transition zone (p < 0.05), while it was only 7% and 13% for the desert steppe and typical steppe, respectively. The presence of herbaceous species mainly caused the differences in variation among three grassland types. (2) Seed density was the highest in the transition zone (114 seeds/m2 and 68 seeds/m2 in the transient and persistent soil seed bank, respectively) (p < 0.05). Additionally, herbaceous species were the main components of the soil seed bank. (3) The similarity index was the highest in the transition zone (p < 0.05), with 38%/44% and 33%/44% for the transient/persistent soil seed bank in 2018 and 2019, respectively. Our study demonstrated that variation in vegetation species composition was very similar to the composition of the seeds accumulated in the soil seed bank. These results warrant further investigation for the mechanism of asymmetric response of productivity to precipitation.


Author(s):  
Josephine Esaete ◽  
Augustine Bongo ◽  
Thomas Lado ◽  
Tomor Bojoi ◽  
Henry Busulwa

Soil seed banks are important for regeneration of degraded wetlands ecosystems. The Sudd wetlands of Juba city have long been encroached for crop cultivation. Seedling germination was monitored in a greenhouse to establish possible natural regeneration in Mindiari, Rejaf and Roton wetlands in the Sudd. Sixty-four species germinated from the soil seed bank of which 12.5% were dominated by Cyperus difformis and Typha capensis. The findings showed that median wetland species richness in Mindiari was 1.5 (interquartile range = 0.75?3.5), Rejaf 2.5 (interquartile range = 1.0 ? 4.0), Roton 3 (interquartile range = 1.0 ? 5.0) while median Shannon-Wiener diversity was 1.5 (1.14 ?1.73), 1.43 (1.01?1.66), 1.15 (0.98?1.67) for Mindiari, Rejaf and Roton respectively. Both the median seed species richness and diversity were not significantly different among the study wetlands. The median of seed density (56.1) was significantly higher in Roton than in Mindiari (36.7) and Rejaf (29.4) wetlands. The NMDS results showed that species composition of Mindiari and Rejaf was different from Roton. It is concluded that growing crops in wetlands did not influence species richness and diversity but it reduced seed density and altered species composition. Although wetland species were not significantly different in the three-wetland categories, dominance of canopy species belonging to Typhaceae and Cyperaceae indicates that these species are resilient to cultivation and could facilitate natural regeneration of cultivated wetlands edges of the Sudd region in Juba. Further research should examine effect of cultivation duration and flooding regimes on soil seed bank species richness, diversity, and density and composition.


2021 ◽  
Vol 69 (1) ◽  
pp. 45
Author(s):  
Andrés García ◽  
Alejandro Loydi ◽  
Roberto A. Distel

Serrated tussock (Nassella trichotoma (Nees) Hack. ex Arechav) is an unpalatable grass species that has been expanding in its native range and invading non-native ranges. In this study in its natural environment, we aimed to describe the spatial relationship between seed density, the cover and density of standing individuals of serrated tussock, the seasonal variation in the seed density in the soil seed bank, and to compare these results with those reported in non-native ranges. We took soil samples seasonally and recorded the cover and density of standing individuals of serrated tussock at two sites in the native Pampas grasslands in central-east Argentina. Seed density was evaluated by seedling emergence and seed extraction. Seed density showed a seasonality trend, with maximum values in the end of summer and minimum values in winter and spring. Seed density was independent of the cover and density of standing individuals of serrated tussock. The values of seed density were lower than those reported in the invaded ranges. Since seeds of serrated tussock are present in the seed bank regardless of the cover and density of its standing individuals, the maintenance of a high cover of desirable species may play a key role in preventing the establishment of serrated tussock in both its natural and invaded ranges.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4447 ◽  
Author(s):  
Wenting Liu ◽  
Tianle Wang ◽  
Shuang Zhang ◽  
Lijun Ding ◽  
Zhijun Wei

Seed germination plays an important role in determining the composition and regeneration of plant populations (Stipa breviflora). However, the influencing factors and strategies employed for seed germination in desert grasslands under grazing remain unknown. Therefore, in this study, the reproductive allocation, seed density, seed properties, and corresponding seed germination rates of S. breviflora were examined. Possible situations encountered during dispersal were also simulated to determine their effects on seed germination. The results showed that reproductive individual density not subjected to grazing were significantly higher than those subjected to moderate and heavy grazing. For seed density and seed bank in soil, the highest values were observed for the no grazing treatment, followed by the moderate and heavy grazing treatments. The seed density for germination of soil seed banks was nearly one-fourth of seed density during the growing season. In addition, grazing treatments affected the phenotypic characteristics of seeds and reduced the lower limit of the weight of germinable seeds. Awn removal significantly increased germination. The longest germination time was observed for seeds that entered the soil at an angle of 0°. Our research demonstrated that grazing negatively affected the desert grassland edificator. Individual plants adopted different adaptation strategies under different grazing intensities; for example, a fixed proportion of the seed number and seed germination number of S. breviflora in the soil seed bank was maintained by exceeding the minimum weight of a seed for seed germination. During seed dispersion, the awn effectively prevented germination under unfavourable conditions and helped seeds enter the soil at an optimal angle for promoting germination.


1993 ◽  
Vol 9 (4) ◽  
pp. 455-467 ◽  
Author(s):  
U. M. Chandrashekara ◽  
P. S. Ramakrishnan

ABSTRACTThe present study showed that the density of germinable seeds in the soil of a humid tropical forest ecosystem at Nelliampathy, in the Western Ghats of Kerala in India, fluctuates sharply at different times of the year. There were more germinable seeds in the soil during the monsoon season. Regeneration was activated after canopy gap formation and thus a decline in the soil seed density in 1-year-old gaps was recorded. However, soil seed density increased with gap age. Differences were found between primary, late secondary and early secondary categories of species with respect to their soil seed bank. There were more seeds of primary species in the soil of natural gaps than in selection felled ones, while the seeds of early secondary shrubs and herbs were more in the soil of selection felled gaps than in natural gaps. The soil seed banks of the primary forest species, being transient, are not an important conservation tool for these species.


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