Seedling establishment from seeds and seed banks in forests under long-term pollution stress: a potential for vegetation recovery

1994 ◽  
Vol 72 (2) ◽  
pp. 143-149 ◽  
Author(s):  
M. Komulainen ◽  
M. Vieno ◽  
V. T. Yarmishko ◽  
T. D. Daletskaja ◽  
E. A. Maznaja

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.

2012 ◽  
Vol 22 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Scott R. Abella ◽  
Judith D. Springer

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.


2010 ◽  
Vol 24 (4) ◽  
pp. 1100-1103 ◽  
Author(s):  
Fernando Augusto Oliveira Silveira ◽  
Jean Carlos Santos ◽  
Geraldo Wilson Fernandes

In this study we investigated the effects of light, temperature, and storage on seed germination of the wild pineapple Ananasananassoides, an understorey species found in cerrado woodlands. Seeds were germinated at temperatures of 15, 20, 25, 30 and 35 ºC and a 12-hr photoperiod and continuous darkness for 30-d. Seeds were photoblastic and the optimum temperatures for germination were 25 and 30 ºC. Seeds stored for 12-mo at room temperature and at 4 ºC were set to germinate at optimum conditions. Germinability of stored seeds did not differ from that of recently collected seeds, regardless of storage temperature, indicating their physiological potential for seed bank formation. Our results suggest that as in tropical rainforests, light may be an important factor controlling recruitment from seed banks for small-sized species from the cerrado woodlands.


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.


Author(s):  
Ali Noha ◽  
Lisanework Nigatu ◽  
Rejila Manikandan

Background: Prosopis juliflora L. is an evergreen exotic weedy species seriously devastating valuable rangeland resources in arid and semi-arid parts of Ethiopia. Its increasing alarming rate of invasiveness had affecting the livelihood of the pastoral communities in Amibara rangeland of Afar National Regional State. Therefore, the aim of this study was to investigate the effects of Prosopis juliflora L. on soil seed bank flora. Methods: The total of 20 soil samples were collected from five sites by measuring sample quadrats of (20 m × 20 m) area were laid out and the soil samples from each quadrant were taken from 5 sub-quadrats/m2, one from the center and four from the corners, at two depths (0-3 cm and 3-10 cm). The soil samples from the identical layers were mixed in plastic bags to form composite sample. Finally, the composite samples were transported to the Haramaya University to conduct seed germination test in the greenhouse. The soil samples were spread thinly (2 cm thickness) over sterilized soil in shallow trays (20 cm × 25 cm) placed on a bench and allowed for seed germination. Result: The total of 38 herbaceous plant species /m2 belongs to 16 families were emerged in the upper and lower layer (0-3 cm and 3-10 cm) of the soil seed bank samples. The highest values of species diversity were (3.17) in Awash-arba, (3.15) in Alaydagi, (3.04) in Kurkura within m2 area at the depth of 0-3 cm. While the least diversity values of 2.75 in Melka-Werer and 2.77 was recorded in Sarkamo. Jaccard’s coefficient similarity index was exhibited high species similarity of 55.6% in the upper soil seed bank layers (0-3 cm) in Melka-were and Sarkamo. Whereas, species similarities of 45.2% were obtained in the lower layer (3-10 cm) soil seed banks in Awash-arba and upper layer soil seed bank in Alaydagi respectively. While species similarity was decreases as 31.8% in the lower layer soil seed banks in Sarkamo and Kurkura. Increasing species richness and the diversity was also noticed in under open canopy upper layer soil seed bank samples, while decreasing richness and diversity observed in under closed canopy. This indicates that the Prosopis juliflora L. tree has high growth retarding potential on its under canopy soil seed bank flora and in the lower layer soil seed bank samples also.


2021 ◽  
Vol 16 (4) ◽  
Author(s):  
Cynthia Sias ◽  
Bethany R. Wolters ◽  
Mark S. Reiter ◽  
Michael L. Flessner

This review explores ways that cover crops alter soil environmental conditions that can be used to decrease seed survival, maintain weed seed dormancy, and reduce germination cues, thus reducing above-ground weed pressures. Cover crops are grown between cash crops in rotation, and their residues persist into subsequent crops, impacting weed seeds both during and after cover crops’ growth. Compared to no cover crop, cover crops may reduce weed seedling recruitment and density via: i) reducing soil temperature and fluctuations thereof; ii) reducing light availability and altering light quality; and iii) trapping nitrogen in the cover crop, thus making it less soil-available to weeds. In addition, cover crops may provide habitat for above- and below-ground fauna, resulting in increased weed seed predation. The allelopathic nature of some cover crops can also suppress weeds. However, not all effects of cover crops discourage weeds, such as potentially increasing soil oxygen. Furthermore, cover crops can reduce soil moisture while actively growing but conserve soil moisture after termination, resulting in time-dependent effects. Similarly, decaying legume cover crops can release nitrogen into the soil, potentially aiding weeds. The multiplicity of cover crop species and mixtures, differing responses between weed species, environmental conditions, and other factors hampers uniform recommendations and complicates management for producers. But, cover crops that are managed to maximize biomass, do not increase soil nitrogen, and are terminated at or after cash crop planting will have the greatest potential to attenuate the weed seed bank. There are still many questions to be answered, such as if targeting management efforts at the weed seed bank level is agronomically worthwhile. Future research on cover crops and weed management should include measurements of soil seed banks, including dormancy status, predation levels, and germination. Highlights - Cover crops alter the weed seed bank environment, influencing survival, dormancy, and germination. - Weed seed germination may be reduced by decreased temperature and fluctuations thereof, light, and soil nitrogen. - Weed seed germination may be increased by greater soil moisture, soil nitrogen, and oxygen. - Management should maximize cover crop biomass, decrease soil nitrogen, and delay termination for the greatest potential. - Future research should include measurements of weed seed banks, including dormancy status, predation, and germination.


2011 ◽  
Vol 80 (4) ◽  
pp. 269-274 ◽  
Author(s):  
Anna J. Kwiatkowska-Falińska ◽  
Małgorzata Jankowska-Błaszczuk ◽  
Maciej Wódkiewicz

Studies on the soil seed banks of fallow lands of different ages were carried out on poor soil abandoned fields and in a fresh coniferous forest in north-eastern Poland. The size and diversity of seed banks was studied with the seedling emergence method. Species abundance (<em><strong>i</strong></em>), density (<em><strong>ii</strong></em>), number of species from different biological groups (<em><strong>iii</strong></em>) and distribution and mean <em>LI</em> value (<em><strong>iv</strong></em>) were analysed as the function of fallow land age. It was found that: (<em><strong>i</strong></em>) species diversity, number of species and ln of density are linear declining function of the fallow land age; (<em><strong>ii</strong></em>) for approx. 25 years the share of diaspores of identified species groups has been relatively similar. Seed banks of 40-50-year-old fallow lands are dominated by <em>Calluna vulgaris</em>, while the seed bank of the old fresh coniferous forest is dominated by dicotyledonous perennials and grasses; (<em><strong>iii</strong></em>) within the first 50 years of succession the persistence of seed banks measured by the Longevity Index increases gradually.


2011 ◽  
Vol 80 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Anna J. Kwiatkowska-Falińska ◽  
Dorota Panufnik-Mędrzycka ◽  
Maciej Wódkiewicz ◽  
Izabela Sondej ◽  
Bogdan Jaroszewicz

The research was conducted on four patches of thermophilous oak wood in Białowieża Primeval Forest: A – with a woodstand: oak + approx. 30-year-old hornbeam + hornbeam brushwood; B – with a hornbeam stand formed by natural seed fall after logging (ca. 1920) oaks; C – after logging oaks and replanted (ca. 1965) with pine and oak; D – with a natural low-density oak stand. Species composition and seed bank density were estimated using the seedling emergence method. Seedling emergence was observed over two vegetation seasons. Research demonstrated that: 1) the species abundance of the seed banks depends on canopy cover (A, B approx. 50 species; C, D approx. 70 species); 2) the floristical similarity (Sørensen's index) of the seed bank and ground vegetation is higher in the undisturbed patch D (0.50) than in disturbed patches (0.30-0.35); 3) species diversity in plots A, B, C, D (H'=12.5; 13.4; 15.5; 16.9) and seed bank density per m<sup>2</sup> (432.5; 958.0; 1486.5; 2268.0) are negatively correlated with the degree of patch shading; 4) the average weight of diaspores in the seed banks of shady plots is lower (A, B approx. 0.003 g) than that of sunny plots (C, D approx. 0.08 g); 5) the share of long-lived diaspores increases in patches after logging.


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.


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