Seed-bank contributions to regeneration of shrub species after clear-cutting and burning

1988 ◽  
Vol 66 (1) ◽  
pp. 169-172 ◽  
Author(s):  
P. Morgan ◽  
L. F. Neuenschwander

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.

1988 ◽  
Vol 3 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Penelope Morgan ◽  
Leon F. Neuenschwander

Abstract Early seral shrub community development following clearcutting is documented for fall broadcast burns aged 0-5 and 15 years on a western redcedar (Thuja plicata)/beadlilly (Clintonia uniflora) habitat type. Shrub cover was dominated by redstem ceanothus (Ceanothus sanguineus), blackberry (Rubus ursinus), thimbleberry (R. parviflorus), common snowberry (Symphoricarpos albus), and 8 other shrub species. Frequency of occurrence differed significantly (P < 0.05) with burn severity (6 of 12 species), but not with burn age (10 of 12 species) up to 15 years after fire. Percent canopy cover of seedlings and sprouts, summed over species, differed with burn severity on burns less than 4 years old. There was greater total cover of rhizomatous shrub sprouts (P < 0.01) on low severity burns. Cover of shrub seedlings was significantly less (P = 0.03) on low severity than on high severity burns. However, there was no difference (P = 0.60) in cover of nonrhizomatous sprouts on high and low severity burns. West. J. Appl. For. 3(1):5-9, January 1988.


1998 ◽  
Vol 76 (7) ◽  
pp. 1188-1197 ◽  
Author(s):  
Heli M. Jutila b. Erkkilä

Seed banks of two seashore meadows were studied on the west coast of Finland (latitude 61°30'-61°33'N, longitude 21°28'-21°41'E). Samples were taken in June to a depth of 10 cm in the geolittoral zone of the grazed and ungrazed transects. The grazed samples were halved lengthwise: one half was grown immediately, the other after cold treatment. One third of the all samples was treated as controls, one third was watered with brackish water, and one third was given a pesticide treatment. Altogether, 13 926 seedlings germinated and 25 species were identified (three annuals, two biennials, and the rest perennials). Most seedlings were perennial monocots, with Juncus gerardii Loisel. the most abundant species. The seed bank was significantly larger and richer in the ungrazed site than in the grazed site. Cold treatment reduced the number of germinating species and seedlings. In the grazed and non-cold-treated samples, the numbers of species and seedlings were highest in the pesticide treatment. In ungrazed samples there were no significant differences among treatments. After the cold treatment, the least number of species and seedlings was produced by the salt-water treatment. Changing brackish water to tap water led to a burst of germination, especially of J. gerardii. The seed bank of the upper geolittoral zone was richer than that of the middle geolittoral. The multivariate classification and ordination groupings are based on the abundances of J. gerardii and Glaux maritima L.; different treatments were not distinguishable. There was a low resemblance between the seed bank and the aboveground vegetation.Key words: seed bank, salinity, pesticide, seashore meadow, cold treatment, vegetation.


2017 ◽  
Vol 57 (2) ◽  
pp. 165-175 ◽  
Author(s):  
Petra S. Yehnjong ◽  
Michael S. Zavada ◽  
Chris Liu

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.


1989 ◽  
Vol 67 (6) ◽  
pp. 1878-1884 ◽  
Author(s):  
Carol E. Wienhold ◽  
A. G. van der Valk

To determine the potential role of seed banks in the restoration of drained wetlands, the seed banks of 30 extant and 52 drained and cultivated prairie potholes were sampled in Iowa, Minnesota, and North Dakota; the potholes had been drained between 5 and 70 years ago. The midsummer vegetation of most of these potholes was also sampled. The number of species in the seed bank of a pothole declined from a mean of 12.3 in extant potholes to 7.5, 5.4, 5.0, 7.4, 3.2, and 2.1 in potholes drained up to 5, 10, 20, 30, 40, and 70 years ago, respectively. The mean total seed density of extant potholes was 3600 seeds/m2. It increased to 7000 seeds/m2 up to 5 years after drainage, but then declined rapidly to 1400, 1200, 600, 300, and 160 after up to 10, 20, 30, 40, and 70 years after drainage. Changes in both species richness and seed density with increasing duration of drainage varied from state to state. About 60% of the species present in the seed banks of extant or recently drained wetlands were not detected in wetlands that had been drained for more than 20 years. Vegetation surveys of extant and drained wetlands indicated that as many or more wetland species not detected in the seed bank were present in the vegetation, as there were wetland species in the seed bank.


2007 ◽  
Vol 37 (3) ◽  
pp. 552-567 ◽  
Author(s):  
Scott R. Abella ◽  
Judith D. Springer ◽  
W. Wallace Covington

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.


2004 ◽  
Vol 82 (7) ◽  
pp. 992-1000 ◽  
Author(s):  
Rick E Landenberger ◽  
James B McGraw

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.


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.


2012 ◽  
Vol 90 (3) ◽  
pp. 287 ◽  
Author(s):  
Jorge A. Meave ◽  
Claudia Flores-Rodríguez ◽  
Eduardo A. Pérez-García ◽  
Marco Antonio Romero-Romero

<p class="p1"><span class="s1">The slash-and-burn agriculture practiced across tropical dry regions results in the elimination of native vegetation. Upon field abandonment, the seed bank becomes a potentially important mechanism of natural regeneration at early successional stages. Soil properties and climate seasonality may affect seed bank characteristics, thus we analyzed the effects of these two factors on seed bank density and composition in agricultural fields of a seasonally dry tropical region of southern Mexico. Soil cores were collected for the rainy and the dry seasons in order to assess changes occurring in the seed bank from the time of harvest to the moment when succession could potentially start (the next rainy season). The 12 studied fields comprised three different soil types recognized by local inhabitants: sandy and stony, silty, and clayey soils, locally known as cascajo, black soil, and red soil, respectively. At each fi eld 20 soil cores (8 cm diameter, 4.5 cm depth) were collected and mixed to form four pooled samples, which were placed in a greenhouse to induce germination. A total of 4,422 seedlings (2,291 seeds m<sup>-2</sup>) representing 40 species were recorded. The most abundant species were, in decreasing order, <em>Melanthera nivea</em>, <em>Rhynchelytrum repens</em>, <em>Waltheria indica</em>, <em>Amaranthus scariosus</em>, <em>Digitaria bicornis</em>, and <em>Cenchrus pilosus</em>. Herbs were the prevailing growth form (&gt; 80% of total richness). No clear pattern was observed in the seed bank related to soil type; however, seed bank characteristics tended to be associated with the time of use of the agricultural fields, a variable that was not controlled in the study. Seed bank species richness was significantly larger in the dry season, and although seed density showed a similar trend, it was not significant. The studied seed banks contain no elements of the regional primary tropical dry forest, which suggests that seed banks in deforested areas cannot guarantee their maintenance beyond forested areas.</span></p>


2013 ◽  
Vol 29 (6) ◽  
pp. 523-529 ◽  
Author(s):  
Denis Lippok ◽  
Florian Walter ◽  
Isabell Hensen ◽  
Stephan G. Beck ◽  
Matthias Schleuning

Abstract:Vast areas of tropical forests have been deforested by human activities, resulting in landscapes comprising forest fragments in matrices of deforested habitats. Soil seed banks (SSB) are essential sources for the regeneration of tropical forests after disturbance. In a fragmented montane landscape in the Bolivian Andes, we investigated SSB in three different habitat types that were associated with different degrees of disturbance, i.e. in forest interior, at forest edges and in deforested habitats. Sampling of habitats was replicated at six sites ranging in altitude from 1950 to 2450 m asl. We extracted seeds from dried soil samples by sieving, classified seeds into morphospecies and size classes, and characterized SSB in terms of density, species richness and composition. We tested effects of disturbance (i.e. habitat type) and altitude on SSB characteristics. Overall, small seeds (<1 mm) dominated SSB (81% of sampled seeds). Seed density and species richness were lowest in deforested habitats, especially in large seeds and distant from adjacent forests (≥20 m), while small-seeded species were most numerous near forest margins. Species turnover between habitats was high. Altitude altered the composition of SSB, but had no effects on seed density and species richness. We conclude that the potential of SSB for natural regeneration of deforested habitats is low and decreases with increasing distance from forest remnants and that forest edges may be eventually invaded by small-seeded species from deforested habitats.


1998 ◽  
Vol 8 (4) ◽  
pp. 493-500 ◽  
Author(s):  
M. Olatunde Akinola ◽  
Ken Thompson ◽  
Susan H. Hillier

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.


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