Viability and abundance of seeds of submerged macrophytes in the sediment of disturbed and reference shoreline marshes in Lake Ontario

1997 ◽  
Vol 75 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Kim Westcott ◽  
Thomas H. Whillans ◽  
Michael G. Fox
Keyword(s):  
Natural Regeneration ◽  
Anthropogenic Disturbance ◽  
Submerged Macrophytes ◽  
Seed Viability ◽  
Lake Ontario ◽  
Seed Banks ◽  
Submerged Macrophyte ◽  
Submerged Vegetation ◽  
Seed Density ◽  
Reference Marsh

The seed banks of six Lake Ontario shoreline marshes were investigated to assess the potential for natural regeneration of sparse submerged macrophyte populations in marshes subjected to anthropogenic disturbance. Twenty-six core samples were taken in each of three disturbed marshes with sparse submerged vegetation, and the number of seeds was compared with samples from three reference marshes containing abundant submerged vegetation. Six cores from each of six marshes were examined to determine whether there was a difference between disturbed and reference marshes in seed density or seed distribution, and germination assays were used to assess differences in seed viability. Seeds of five submerged macrophyte taxa were identified in substrate samples of the six marshes. Mean seed density was significantly higher in the three reference marshes (4082 – 47 623 seeds/m2) than in the three disturbed marshes (0–2041 seeds/m2). The density of seedlings of submerged macrophytes germinating in reference marsh samples ranged from 333 to 2406 seedlings/m2, whereas no seedlings germinated from disturbed marsh samples. The deeper sediments (7–14 cm sediment depth) in the reference marshes had comparable seed densities to those in the shallower sediments, whereas seeds were found in only the deeper sediments of the disturbed marshes. These data suggest that regeneration from buried seeds is unlikely in the disturbed marshes, even if improvements occur in the environmental conditions that have historically inhibited the growth of submerged macrophytes. Key words: submerged macrophytes, anthropogenic disturbance, Lake Ontario, seed banks, natural regeneration.

scholarly journals Soil Seed Banks of Tree Species from Natural Forests, Restoration Sites, and Abandoned Areas in Chiang Mai, Thailand

2021 ◽  
pp. 167-180
Author(s):  
Patsavipich Rungrojtrakool ◽  
Pimonrat Tiansawat ◽  
Arunothai Jampeetong ◽  
Dia Panitnard Shannon ◽  
Sutthathorn Chairuangsri
Keyword(s):  
Seed Dispersal ◽  
Species Composition ◽  
Tree Species ◽  
Natural Regeneration ◽  
Seed Banks ◽  
Seed Density ◽  
Natural Forests ◽  
Chiang Mai ◽  
Soil Seed Banks ◽  
Standing Vegetation

Soil seed banks have been used for investigation of natural regeneration of forests. In this study, we compared seed density and species composition of soil seed banks of trees among natural forests, restored forests of different ages, and abandoned agricultural land. The soil seed banks were collected from a natural forest (NF), 12-year-old and 17-year-old restoration sites (RF12y and RF17y), and 17-year-old abandoned site (AA) at Ban Mae Sa Mai, Chiang Mai, Thailand. A seedling emergence technique was used to assess seed density and species of emerged seedlings was identified. We found 5-8 tree species at each site. Seed densities in the study areas ranged from 43 to 298 seeds/m2. The seed density of RF12y was significantly higher than that of both NF and AA but not significantly different than RF17y (p < 0.01). Although there was no significant relationship between the restoration ages and the seed densities of the soil seed banks, the species composition of standing vegetation was related to the seed bank species. Sorensen’s similarities between the species composition of the soil seed banks and the existing trees in each area were between 0 and 13.79%, suggesting seed dispersal of both within and across study sites. Eight out of fourteen species in the soil seed banks were dispersed into restoration sites without standing vegetation of those species. Seven of those were animal-dispersed species. The selected native trees, framework species, attracted small seed dispersers into the study areas, especially at the restoration sites. This finding suggests that active forest restoration improved natural regeneration in restoration sites as well as neighboring areas via seed dispersal.

scholarly journals Natural vegetation regeneration from soil seed banks in the cultivated edges of Sudd wetlands in Juba, Southern Sudan

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Josephine Esaete ◽  
Augustine Bongo ◽  
Thomas Lado ◽  
Tomor Bojoi ◽  
Henry Busulwa
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Seed Bank ◽  
Natural Regeneration ◽  
Soil Seed Bank ◽  
Seed Banks ◽  
Interquartile Range ◽  
Seed Density ◽  
Soil Seed Banks ◽  
Species Richness And Diversity

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.

Distribution pattern of epiphytic microcrustaceans in relation to different macrophyte microhabitats in a shallow wetland (Upo wetlands, South Korea)

2015 ◽  
Vol 44 (2) ◽  
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim ◽  
Kwang-Seuk Jeong ◽  
Gea-Jae Joo
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Submerged Macrophytes ◽  
Submerged Macrophyte ◽  
Ceratophyllum Demersum ◽  
Suitable Habitat ◽  
Seasonal Growth ◽  
Spirodela Polyrhiza ◽  
Macrophyte Species ◽  
Salvinia Natans

AbstractMacrophytes determine the physical complexity of aquatic environments and provide a suitable habitat for colonization by microcrustaceans. We evaluated the effects of a seasonal growth pattern and structure of macrophyte species on epiphytic microcrustaceans collected from macrophyte surfaces (stems and leaves) in shallow wetlands from May 2011 to October 2012. In 2011, epiphytic microcrustaceans that preferred free-floating macrophytes (Spirodela polyrhiza and Salvinia natans) and submerged macrophytes (Potamogeton crispus and Ceratophyllum demersum) were affected by the seasonal growth of these species. Epiphytic microcrustaceans were abundant on the surface of Spirodela polyrhiza in June and August and on Salvinia natans in September and October. In 2012, epiphytic microcrustaceans preferred submerged macrophyte species over the free-floating ones. The results of stable isotope analysis showed that epiphytic microcrustaceans depend on epiphytic particulate organic matter (EPOM) from each macrophyte species rather than on suspended particulate organic matter. Small species (Coronatella rectangula, Pleuroxus laevis, and Chydorus sphaericus) used EPOM (dominated by epiphytic algae) on free-floating and submerged macrophyte species; however, relatively larger species (Ilyocryptus spinifer and Macrothrix rosea) used EPOM only from submerged macrophytes. Based on these findings, we conclude that the distribution of epiphytic microcrustaceans is determined by seasonal characteristics, morphology of macrophyte species, and abundance of food resources.

scholarly journals Growth of Microcystis strains isolated from environments with the presence and absence of submerged macrophytes in coexistence with Ceratophyllum demersum

2021 ◽  
Vol 43 ◽  
pp. e57734
Author(s):  
Rafael Henrique de Moura-Falcão ◽  
Ariadne do Nascimento Moura ◽  
Cihelio Alves Amorim
Keyword(s):  
Growth Rate ◽  
Submerged Macrophytes ◽  
T Test ◽  
Submerged Macrophyte ◽  
Cyanobacterial Blooms ◽  
Growth Delay ◽  
Ceratophyllum Demersum ◽  
Significant Difference ◽  
Presence And Absence ◽  
And Control

Cyanobacterial blooms can cause severe ecological and health problems in drinking water reservoirs. To alleviate this problem, allelopathically active submerged macrophytes can be used to reduce cyanobacterial growth. Accordingly, this study aimed to evaluate the sensitivity of strains of the Microcystis aeruginosa complex isolated from reservoirs with the presence and absence of submerged macrophytes to the allelochemicals of Ceratophyllum demersum. A coexistence experiment was carried out between the submerged macrophyte C. demersum and four Microcystis strains, with two treatments for each strain, one in coexistence with the submerged macrophyte (7 g L-1) and control (in the absence of the macrophyte). Two strains of M. aeruginosa (BMIUFRPE-06 and BMIUFRPE-07) and two of M. panniformis (BMIUFRPE-08 and BMIUFRPE-09) were used, which were isolated from Cajueiro (with submerged macrophytes) and Tapacurá (without submerged macrophytes) reservoirs, respectively. The biomass of Microcystis strains from the reservoir without macrophytes (BMIUFRPE-08 and BMIUFRPE-09) was significantly inhibited in 96% (T-test: p < 0.01) and 74% (T-test: p< 0.05), when compared to the control, respectively, with lower values of growth rates (ANOVA: p < 0.05). The strains isolated from the reservoir with macrophytes (BMIUFRPE-06 and BMIUFRPE-07) showed a growth delay (biomass reductions of 44 and 58%, respectively) in the coexistence treatment but without significant difference from the control on the sixth day of the experiment (biomass - T-test: p > 0.05; growth rate - ANOVA: p > 0.05). These results suggest that strains isolated from environments with submerged macrophytes are less sensitive to allelochemicals of these plants, as these strains may be adapted to the coexistence with submerged macrophytes.

scholarly journals Characterization and ecological significance of a seed bank from the Upper Pennsylvanian Wise Formation, southwest Virginia

2017 ◽  
Vol 57 (2) ◽  
pp. 165-175 ◽  
Author(s):  
Petra S. Yehnjong ◽  
Michael S. Zavada ◽  
Chris Liu
Keyword(s):  
Seed Size ◽  
Seed Bank ◽  
Seedling Establishment ◽  
Environmental Variability ◽  
Seed Banks ◽  
Evolutionary Strategy ◽  
Predator Population ◽  
Seed Density ◽  
Soil Seed Banks ◽  
Large Seed

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.

High seed viability recorded in an endangered endemic species, 'Isoplexis isabelliana' (Scrophulariaceae), after more than 30 years of storage in a conservation seed bank

2021 ◽  
Vol 42 ◽  
pp. e69341
Author(s):  
Miguel Ángel González Pérez ◽  
Nereida Cabrera-García ◽  
Isabel Cayon-Fernández
Keyword(s):  
Seed Bank ◽  
Germination Rate ◽  
Genetic Material ◽  
Natural Populations ◽  
Seed Viability ◽  
Seed Storage ◽  
Botanical Garden ◽  
Storage Conditions ◽  
Seed Banks ◽  
Ex Situ

Conservation seed banks are essential for ex-situ conservation of genetic biodiversity. These institutions are especially relevant for threatened species and play a vital role in their conservation by preserving genetic material. However, samples deposited in the seed banks must germinate when necessary to use them (i.e., recovery plans, etc.). This study uses four accessions of the endemic endangered species from Gran Canaria Island (Canary Islands), Isoplexis isabelliana (Webb & Berthel.) Masf. (Scrophulariaceae). Germination tests were carried out to measure seed viability through time and the possible impact of seed storage on their viability. These accessions have been kept in the seed bank for four months to thirty years under different storage conditions. Germination results differed for seeds after 45 days of exposition using 16 hours light and 8 hours darkness at 17 °C. Accessions kept in the seed bank, independently of storage, showed a high germination percentage (89%). Whereas the accessions with rough storage conditions showed a 0% germination rate. The results highlighted the good state of conservation of the material deposited in the Seed Bank of the Botanical Garden "Viera y Clavijo" and the reliability of the temperature and humidity conditions in which the seeds of I. isabelliana have been stored. We consider these results as momentous since several natural populations of I. isabelliana has been affected by the last forest fire on the island.

Controls on phytoplankton physiology in Lake Ontario during the late summer: evidence from new fluorescence methods

2007 ◽  
Vol 64 (1) ◽  
pp. 58-73 ◽  
Author(s):  
Katharine L Pemberton ◽  
Ralph EH Smith ◽  
Greg M Silsbe ◽  
Todd Howell ◽  
Susan B Watson
Keyword(s):  
Anthropogenic Disturbance ◽  
Late Summer ◽  
Lake Ontario ◽  
Lower Surface ◽  
Nutrient Ratios ◽  
Surface Mixed Layer ◽  
P Deficiency ◽  
Photosynthetic Physiology ◽  
Physiological Variations

Fast repetition rate fluorescence (FRRF) and spectral fluorescence, together with measures of nutrients and pigments, were used to characterize the composition and photosynthetic physiology of Lake Ontario phytoplankton in late summer and relate them to environmental conditions. Two stations demonstrated effects from relatively heavy anthropogenic disturbance and showed that the response of phytoplankton physiology to different impacts is highly variable. Other stations were more similar in phytoplankton composition, and in situ fluorescence yields ([Formula: see text]) in the lower surface mixed layer suggested good physiological condition (0.45–0.50). Nutrient ratios and mean irradiance indicated a general state of light saturation and slight phosphorus (P) deficiency, but physiological variations among stations were unrelated to measures of P deficiency. Fluorescence yields often decreased when surface layer samples were held in the dark, consistent with an induction of chlororespiration and prior exposure to supersaturating levels of irradiance. Comparative estimates of photosynthesis by FRRF and 14C revealed disparities suggestive of substantial differences between in situ and incubation methods, while spectral fluorescence appeared to underestimate cyanobacterial abundance. FRRF parameters, particularly [Formula: see text], were effective in identifying higher-impact stations and showed promise as an efficient means of characterizing variations in phytoplankton condition that may underlie phenomena such as taste and odour production.

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
Keyword(s):  
Seed Bank ◽  
Seedling Survival ◽  
Habitat Type ◽  
Canopy Cover ◽  
Abundant Species ◽  
Seed Banks ◽  
Thuja Plicata ◽  
Seed Density ◽  
Shrub Species ◽  
Clear Cutting

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.

Reproductive and ecophysiological attributes of the rare Gardenia actinocarpa (Rubiaceae) compared with its common co-occurring congener, G. ovularis

2001 ◽  
Vol 49 (4) ◽  
pp. 471 ◽  
Author(s):  
Olusegun O. Osunkoya ◽  
Perry W. Swanborough
Keyword(s):  
Competitive Ability ◽  
Seed Viability ◽  
Seed Banks ◽  
Reproductive Period ◽  
Dispersal Ability ◽  
Soil Seed Banks ◽  
Ecophysiological Traits ◽  
Closed Forest ◽  
Female Tree ◽  
Light Gaps

Gardenia actinocarpa Puttock (rare) and G. ovularis F.M.Bailey (widespread) are closely related co-occurring shrub–small trees of rainforests of far north Queensland, Australia.Gardenia actinocarpa is endemic to alluvial lowlands along Noah–Oliver Creeks of Cape Tribulation, whereasG. ovularis spans a wider habitat and occurs on a range of substrates and altitudes. The rare G. actinocarpa is cryptically and strictly dioecious, with a longer reproductive period (9 months) and a low fecundity (1.77 fruits per female tree). In contrast, G. ovularis, although also dioecious, has a shorter reproductive phase (4 months) and produces more fruits (35.76 fruits per female tree), some of which may occur in the absence of fertilisation (apomixis). Under different regimes of photosynthetically active radiation (PAR), seed germination percentages and patterns were similar (70–90%) in the two species, although at 37% PAR G. actinocarpa has lower germination (55–68%). The rare G. actinocarpa loses seed viability very rapidly (G. ovularis (37%). Gardenia actinocarpa grows and survives in both closed forest understorey and in small gaps, while G. ovularis prefers light gaps (both small and large). Net photosynthetic measurements of seedlings grown at 2.5 and 37% PAR suggest that the physiological performance of G. actinocarpa is not inferior to that of G. ovularis, although the latter exhibits greater plasticity. In a density-dependent seedling growth experiment, G. actinocarpa, surprisingly, has a superior competitive ability. Thus, the rarity ofG. actinocarpa may be a result of limited fecundity, reduced seed dispersal ability and lack of soil seed-banks rather than inferior vegetative and ecophysiological traits.

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