Seed dispersal and seedling establishment of Linaria vulgaris Mill.

1991 ◽  
Vol 71 (3) ◽  
pp. 771-782 ◽  
Author(s):  
Léonie B. Nadeau ◽  
Jane R. King
Keyword(s):  
Seed Dispersal ◽  
Seedling Establishment ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Parent Plant ◽  
Linaria Vulgaris ◽  
Root Piece ◽  
Seedling Distribution ◽  
Seed Deposition ◽  
Major Factors

The importance of seeds to the establishment and spread of Linaria vulgaris infestations in Alberta was assessed in 1988 and 1989. Stands were established on 17 May 1988. One 10-cm-long root piece with a 10-cm-tall shoot was planted in the centre of each of nine plots on fallow land and of nine plots in a barley crop. Over 90% of seeds in 1988, and over 80% in 1989 fell within a 0.5-m radius of the parent plants with very few seeds falling outside a 1.5-m radius. Seed deposition vs. distance followed a negative polynomial function. It was estimated that over 210 000 seeds m−2 fell less than 0.5 m away from the parent plant over the 1988 growing season. The presence of Gymnaetron sp. and Brachypterolus sp. in 1989 reduced seed deposition to a total of 1410 seeds m−2 within 0.5 m of the parent plant. The few seedlings that were established occurred in clumps, with densities varying from 1.3 to 7.0 seedlings cm−2 in May and from 0.8 to 7.8 seedlings cm−2 in June 1989. In 1988, total seedling emergence per plot varied between 0.13 and 0.23%. Seed viability and dormancy were major factors influencing seedling establishment. Seed viability was as low as 40% (tetrazolium test), and germination was maximized in the laboratory following a wet stratification at 5 °C for a period of at least 8 wk. Key words: Toadflax, Linaria vulgaris, seed dispersal, seedling establishment, seedling distribution

Dispersal and establishment of slender thistle, Carduus pycnocephalus L. as affected by ground cover

1985 ◽  
Vol 36 (6) ◽  
pp. 791 ◽  
Author(s):  
AR Harradine
Keyword(s):  
Seed Dispersal ◽  
Seedling Establishment ◽  
Ground Cover ◽  
The Other ◽  
Grass Species ◽  
First Year ◽  
Parent Plant ◽  
Annual Grass

After 3 years of spread from sown infestations, slender thistle density in spring was 0.12 and 4.67 plants m-2 for plots in which the ground cover was dominated by cocksfoot and annual grass species, respectively. On plots maintained free of plants other than slender thistle ('bare plots'), the corresponding density was 47.31 plants m-2. Slender thistle seed was dispersed at least 10 m from the parent plant in the first year of seeding and plants were evenly spread over the bare plots after 2 years. After 3 years, slender thistle ingress was still occurring on the other plots. The results indicate the importance of ground cover, either of living plants or of litter, in reducing seedling establishment and seed dispersal of slender thistle.

Patterns of willow seed dispersal, seed entrapment, and seedling establishment in a heavily browsed montane riparian ecosystem

2005 ◽  
Vol 83 (6) ◽  
pp. 678-687 ◽  
Author(s):  
Edward A Gage ◽  
David J Cooper
Keyword(s):  
Seed Dispersal ◽  
Spatial Patterns ◽  
Cervus Elaphus ◽  
Seedling Establishment ◽  
Surface Relief ◽  
Seedling Emergence ◽  
Rocky Mountain ◽  
Soil Surface ◽  
Seed Rain ◽  
Seed Sources

Declines in riparian willow (Salix spp.) communities in Rocky Mountain National Park, Colorado, USA , coincident with a large increase in elk (Cervus elaphus L.) populations, has raised concerns about the future of willow communities. To identify possible constraints on willow establishment in two heavily browsed riparian areas, in 2000 and 2001, we examined seed dispersal phenology, germinability, and the spatial patterns of aerial seed rain, quantified the effects of soil surface relief, texture, and moisture on seed entrapment, and examined natural patterns of seedling emergence in relation to seed source proximity. All species dispersed seeds following peak streamflow and exhibited high germination rates (85%–99%). Total seed rain differed between years, although broad spatial patterns were similar. Seed rain density as high as 7650 seeds/m2 occurred in reference areas but declined by over two orders of magnitude in heavily disturbed areas and by >90% within 200 m of seed sources. Seed entrapment rates varied significantly with soil moisture and surface relief, but not with texture, and were low (<30%) regardless of treatment. Seedling density declined with distance from seed sources, suggesting that propagule availability may limit initial seedling establishment. Without a change in elk population or behavior, or intervention by park managers, degradation of willow communities will likely continue.Key words: Salix, riparian, dispersal, ungulates, elk.

Black spruce regeneration at the treeline ecotone: synergistic impacts of climate change and caribou activityThis article is a contribution to the series Tree recruitment, growth, and distribution at the circumpolar forest–tundra transition.

2011 ◽  
Vol 41 (3) ◽  
pp. 460-468 ◽  
Author(s):  
Geneviève Dufour Tremblay ◽  
Stéphane Boudreau
Keyword(s):  
Climate Warming ◽  
Seedling Establishment ◽  
Black Spruce ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Seed Viability ◽  
Climatic Conditions ◽  
Tree Regeneration ◽  
Lichen Cover ◽  
Recent Climate

Tree regeneration at treeline is often inhibited by harsh climatic conditions and ecological constraints such as the presence of a continuous lichen cover. The objective of this study was to verify if recent climate warming and increased caribou (Rangifer tarandus L.) activity, which destroys the lichen cover, could act synergistically to increase black spruce (Picea mariana (Mill.) B.S.P.) regeneration. We collected cones produced in 2006–2007 to compare seed viability with data from 1989 to 1995. We conducted experimental plantations (field and controlled conditions) to determine if germination and seedling emergence were higher in disturbed environments where mineral soil was exposed. We sampled naturally established seedlings to evaluate the relationship between the year of establishment and caribou activity and to compare growth in disturbed and undisturbed environments. We found that seed viability was significantly higher in 2006–2007 compared with 1989–1995. The number of germinated seeds per cone increased by a factor >1000. Germination and seedling establishment were higher in the disturbed environment (mineral soil). Finally, although seedling establishment in areas with continuous lichen cover was rather constant over the last 50 years, 73.5% of the seedlings recorded on bare mineral soil became established in the years following high caribou activity. Our results suggest that climate warming and caribou activity are likely to act synergistically to promote black spruce regeneration at treeline.

Caching territoriality and site preferences by a scatter‐hoarder drive the spatial pattern of seed dispersal and affect seedling emergence

2021 ◽  
Author(s):  
Loreto Martínez‐Baroja ◽  
Lorenzo Pérez‐Camacho ◽  
Pedro Villar‐Salvador ◽  
Salvador Rebollo ◽  
Alexandro B. Leverkus ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Spatial Pattern ◽  
Seedling Emergence ◽  
Site Preferences

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

scholarly journals Potential Role of Sequential Glufosinate and Foramsulfuron Applications for Management of Fescues (Festucaspp.) in Wild Blueberry

2017 ◽  
Vol 31 (1) ◽  
pp. 100-110 ◽  
Author(s):  
Scott N. White ◽  
Shanthanu Krishna Kumar
Keyword(s):  
Field Study ◽  
Seed Production ◽  
Potential Role ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Early Spring ◽  
Seedling Mortality ◽  
Wild Blueberry

Sheep and hair fescue are perennial, tuft forming grasses that spread by seed and form dense sods in wild blueberry fields. These sods compete with the crop for resources and hinder harvest. Field and greenhouse studies were conducted in 2015 to evaluate 1) the effect of sequential glufosinate and foramsulfuron applications on suppression of fescues in the greenhouse and field, and 2) efficacy of glufosinate and foramsulfuron on fescue seedlings when applied at 2, 4, 6, and 8 wk after seedling emergence in the greenhouse. Glufosinate applications at 750 and 1,005 g ai ha−1followed by foramsulfuron application at 35 g ai ha−1reduced fescue leaf number and biomass relative to foramsulfuron application alone in the greenhouse. In the field study, fescue flowering tuft density, tuft inflorescence height, seed production, and seed viability were reduced by foramsulfuron alone, but there was a trend towards lower seed production and tuft height when fescues were treated with glufosinate at 1,005 g ha−1followed by foramsulfuron. Foramsulfuron caused low seedling mortality at all application timings evaluated, but glufosinate caused >90% mortality in seedlings when applied at 2, 4, 6, or 8 wk after seedling emergence. Our results suggest that sequential applications of these herbicides are less effective under field conditions relative to results obtained in the greenhouse, though burndown glufosinate applications may have a role in reducing fescue seedling recruitment. Additional research should be conducted to determine the effect of early spring and autumn glufosinate applications on fescue seedling recruitment and suppression of established fescue tufts with subsequent foramsulfuron applications.

Seed dispersal interactions promoting plant invasions.

2020 ◽  
pp. 90-104
Author(s):  
M. Celeste Díaz Vélez ◽  
Ana E. Ferreras ◽  
Valeria Paiaro
Keyword(s):  
Seed Germination ◽  
Seed Dispersal ◽  
Seedling Establishment ◽  
Native Species ◽  
Native Plants ◽  
Woody Species ◽  
Native Plant ◽  
Invasional Meltdown ◽  
Native Plant Species ◽  
Origin Life

Abstract Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.

scholarly journals Effect of desiccation temperature on viability of immature dandelion (Taraxacum agg.) seeds dried in mowed inflorescences

2010 ◽  
Vol 56 (No. 12) ◽  
pp. 580-583 ◽  
Author(s):  
Z. Martinková ◽  
A. Honěk
Keyword(s):  
Seed Dispersal ◽  
High Temperatures ◽  
Seed Viability ◽  
Late Summer ◽  
Seed Maturation ◽  
Ripe Seed ◽  
Viable Seeds

After flowering has ceased, dandelion (Taraxacum agg.) capitula close to enable maturation of seeds. In late summer the period of seed maturation lasts for 9 days. The capitula mowed later than 4 days after the start of this period and desiccated at 25&deg;C produce viable seeds. If cut and prostrated on insolated ground inflorescences can experience temperatures exceeding 50&deg;C which may impair seed viability. We determined the effect of desiccation temperature (5, 15, 25, 35, 45 or 55&deg;C) on viability of ripening seeds using inflorescences harvested on September 5, 2008 at Prague-Ruzyne (50&deg;05'N, 14&deg;18'09 E), five days after flowering ceased (about 4 days before seed dispersal). As control, ripe seeds were collected at dispersal on the same day and desiccated at identical temperatures. Desiccated seeds were germinated at constant 17&deg;C. Ripening seeds of maturing capitula only remained germinable if desiccation temperatures were &le; 35&deg;C (optimum 25&deg;C) and were killed at 45 and 55&deg;C. The viability of ripe seed was not affected by any of the desiccation temperatures. Time of germination of 50% seeds that germinated was significantly shorter in ripe than ripening seeds. Exposure of mowed dandelion inflorescences on insolated ground (solarization) may thus decrease production of viable seeds because of high temperatures experienced during desiccation. &nbsp;

Pattern and impact of hornbill seed dispersal at nest trees in a moist evergreen forest in Thailand

2004 ◽  
Vol 20 (5) ◽  
pp. 545-553 ◽  
Author(s):  
Shumpei Kitamura ◽  
Takakazu Yumoto ◽  
Pilai Poonswad ◽  
Naohiko Noma ◽  
Phitaya Chuailua ◽  
...  
Keyword(s):  
Seed Dispersal ◽  
Breeding Season ◽  
Seedling Survival ◽  
Evergreen Forest ◽  
Seedling Mortality ◽  
Entire Process ◽  
Nest Sites ◽  
Seed Deposition ◽  
Number Of Seeds

Following the entire process of frugivore seed dispersal, from intake of seeds to seed deposition, is a difficult task. One alternative is to monitor areas of heavy seed rain deposited by animals. We quantified the number of seeds deposited by hornbills and followed the fates of these seedlings for 3 y to evaluate the effectiveness of hornbill seed dispersal at nest trees, on the basis of seedling survival. For 14 mo, fallen fruits and seeds were collected in traps established around four nest trees of each of two hornbill species (Aceros undulatus and Anthracoceros albirostris) and the seedlings were monitored in adjacent quadrats. Seedfall and seedlings of species represented in hornbill diets occurred at significantly higher densities in the traps/quadrats in front of nest cavities than in other traps/quadrats. Fewer seedling species and individuals germinated under nest trees than expected from the composition of the seedfall. Our results suggest that the quality of hornbill seed dispersal might be poor at nest trees due to the highly concentrated seedfall, which results in high seed and seedling mortality. Although seed deposition at nest trees is a useful guide to hornbill diet during the breeding season, it is clearly not of benefit to the plants involved. However, the pattern and consequences of hornbill seed dispersal at nest sites is likely very different from that during the non-breeding season.

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