Seed rain, seedling establishment and clonal growth strategies on a glacier foreland

1996 ◽  
Vol 7 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Jürg Stöcklin ◽  
Esther Bäumler
Keyword(s):  
Seedling Establishment ◽  
Clonal Growth ◽  
Seed Rain ◽  
Growth Strategies ◽  
Glacier Foreland

scholarly journals Intraspecific Root Grafts and Clonal Growth Within Ailanthus altissima Stands Influence Verticillium nonalfalfae Transmission

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1070-1077 ◽  
Author(s):  
E. S. O’Neal ◽  
D. D. Davis
Keyword(s):  
Verticillium Wilt ◽  
Clonal Growth ◽  
Causal Agent ◽  
Ailanthus Altissima ◽  
Growth Strategies ◽  
Rapid Transmission ◽  
Verticillium Nonalfalfae ◽  
Root Grafts ◽  
Growth Habits

Verticillium nonalfalfae, causal agent of Verticillium wilt, is being considered as a biocontrol for the highly invasive Ailanthus altissima in Pennsylvania. This soilborne fungus is extremely virulent on Ailanthus and rapidly transmitted from diseased to healthy trees within Ailanthus stands. The rapid transmission of the fungus could be facilitated by root grafts, but neither root graft formation in Ailanthus nor Verticillium transmission by root grafts in trees has been reported. Here, V. nonalfalfae transmission between diseased and healthy Ailanthus trees via intraspecific root grafts and clonal growth is evaluated. Using air-spade excavation, dye translocation, and root graft inoculations, functional root grafts were detected between Ailanthus trees and transmission of V. nonalfalfae across root grafts demonstrated. Inoculation of one Ailanthus parent stem resulted in 187 root sprouts showing Verticillium wilt symptoms 12 months after inoculation. This study revealed that clonal growth and root grafts, normally advantageous growth habits, leave Ailanthus stands vulnerable to widespread V. nonalfalfae infection. This study also broadens the understanding of the Ailanthus-Verticillium pathosystem, growth strategies of invasive Ailanthus, and epidemiology of Verticillium wilt within trees.

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.

scholarly journals Spatial concordance between seed rain and seedling establishment in bird-dispersed trees: does scale matter?

2005 ◽  
Vol 93 (4) ◽  
pp. 693-704 ◽  
Author(s):  
DANIEL GARCÍA ◽  
JOSÉ RAMÓN OBESO ◽  
ISABEL MARTÍNEZ
Keyword(s):  
Seedling Establishment ◽  
Seed Rain ◽  
Spatial Concordance

scholarly journals Intraspecific sexual competition in the clonal gynodioecious herb Glechoma hederacea in response to patchy nutrient distribution

Plant Ecology ◽  
2020 ◽  
Author(s):  
Nathan A. Harris ◽  
Sandra Varga
Keyword(s):  
Sexual Dimorphism ◽  
Clonal Growth ◽  
Soil Nutrient ◽  
Biomass Accumulation ◽  
Total Biomass ◽  
Growth Strategies ◽  
Nutrient Distribution ◽  
Sexual Competition ◽  
Competitive Abilities ◽  
Glechoma Hederacea

Abstract Plants have developed numerous strategies to maximise resource uptake in response to the highly heterogeneous resource distribution in soils. Clonal growth enables plants to scavenge larger surfaces, potentially maximising nutrient acquisition by selectively growing in nutrient-rich patches. However, the production of clonal units put plants into higher intraspecific competition. In gynodioecious clonal plants, genders usually exhibit sexual dimorphism in several growth and life history traits, but whether the genders have different competitive abilities and whether these are affected by nutrient distribution is underexplored. Here, we investigated whether the genders of Glechoma hederacea have different competitive abilities and whether these are affected by soil nutrient distribution using a greenhouse pot experiment. Female and hermaphrodite ramets were grown either alone or in competition with the same or the opposite gender in two different soil nutrient distributions for four months. Our results show that competition was the strongest factor affecting biomass accumulation and allocation. Females and hermaphrodites showed little sexual dimorphism in total biomass accumulation, but they differed in how they allocated this biomass between roots and shoots and in their clonal growth strategies in response to soil nutrient distribution. Taken together, our results indicate that soil nutrient distribution affects the competitive abilities of G. hederacea in a gender-specific manner. In the field, these differences would determine the structure and the dynamics of the two genders within the populations.

Clonal Growth Strategies Along Flooding and Grazing Gradients in Atlantic Coastal Meadows

2010 ◽  
Vol 46 (2-3) ◽  
pp. 219-235 ◽  
Author(s):  
Marie-Lise Benot ◽  
Cendrine Mony ◽  
Amandine Merlin ◽  
Benoit Marion ◽  
Jan-Bernard Bouzillé ◽  
...  
Keyword(s):  
Clonal Growth ◽  
Growth Strategies ◽  
Coastal Meadows ◽  
Atlantic Coastal

Seed rain and seedling establishment of the dioecious tree Neolitsea sericea (Lauraceae): effects of tree sex and density on invasion into a conifer plantation in central Japan

2005 ◽  
Vol 83 (9) ◽  
pp. 1144-1150 ◽  
Author(s):  
Nobumasa Arai ◽  
Tomohiko Kamitani
Keyword(s):  
Survival Rate ◽  
Seedling Establishment ◽  
Tree Species ◽  
Seedling Survival ◽  
Local Scale ◽  
Seed Rain ◽  
Central Japan ◽  
Dioecious Plants ◽  
Regeneration Pattern ◽  
Conifer Plantation

We studied the effects of differences in parent sex and density on seed rain and seedling and (or) sapling recruitment in a dioecious tree species (Neolitsea sericea (Bl.) Koidz.) with bird-dispersed seeds. We established four microhabitats: male or female trees inside or outside a single patch. The density of bird-disseminated seeds was significantly higher beneath females and inside the patch than beneath males and single trees outside the patch; this led to higher density of emerged seedlings inside the patch. The survival rate of germinated seedlings was also higher inside the patch than below single trees. In contrast, the survival rate of saplings was highest beneath males outside the patch, although very few seeds are dispersed beneath single males. Seedling and sapling recruitment beneath females and inside the patch will be accelerated owing to higher density of dispersed seeds, high seedling survival, and greater sapling density. In contrast, recruitment beneath males will be very slow. However, microhabitats beneath males are probably more suitable for seedling and sapling recruitment than microhabitats beneath females, since the survival rate of saplings was higher beneath males. Parental sex-biased seed rain and seedling and (or) sapling recruitment in dioecious plants may explain the regeneration pattern at a local scale.

scholarly journals Clonal growth strategies of Reynoutria japonica in response to light, shade, and mowing, and perspectives for management

NeoBiota ◽  
2020 ◽  
Vol 56 ◽  
pp. 89-110 ◽  
Author(s):  
François-Marie Martin ◽  
Fanny Dommanget ◽  
François Lavallée ◽  
André Evette
Keyword(s):  
Environmental Conditions ◽  
Clonal Growth ◽  
Invasive Plant ◽  
Light Stress ◽  
Growth Patterns ◽  
Control Measures ◽  
Growth Strategies ◽  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Habitat Patches

Many of the most invasive plant species in the world can propagate clonally, suggesting clonality offers advantages that facilitate invasion. Gaining insights into the clonal growth dynamics of invasive plants should thus improve understanding of the mechanisms of their dominance, resilience and expansion. Belonging to the shortlist of the most problematic terrestrial invaders, Reynoutria japonica var. japonica Houtt. (Japanese knotweed) has colonized all five continents, likely facilitated by its impressive ability to propagate vegetatively. However, its clonal growth patterns are surprisingly understudied; we still do not know how individuals respond to key environmental conditions, including light availability and disturbance. To contribute to filling this knowledge gap, we designed a mesocosm experiment to observe the morphological variation in R. japonica growth in homogeneous or heterogeneous conditions of light stress (shade) and disturbance (mowing). Rhizome fragments were planted in the middle of large pots between two habitat patches that consisted of either one or a combination of the following three environmental conditions: full light without mowing, full light with frequent mowing, or shade without mowing. At the end of the experiment, biomass and traits related to clonal growth (spacer and rhizome lengths, number of rhizome branches, and number of ramets) were measured. After 14 months, all individuals had survived, even those frequently mowed or growing under heavy shade. We showed that R. japonica adopts a ‘phalanx’ growth form when growing in full light and a ‘guerrilla’ form when entirely shaded. The former is characteristic of a space-occupancy strategy while the latter is more associated with a foraging strategy. In heterogeneous conditions, we also showed that clones seemed to invest preferentially more in favorable habitat patches rather than in unfavorable ones (mowed or shaded), possibly exhibiting an escape strategy. These observations could improve the management of this species, specifically by illustrating how aggressive early control measures must be, by highlighting the importance of repeated mowing of entire stands, as this plant appears to compensate readily to partial mowing, and by informing on its potential responses towards the restoration of a cover of competitive native plants.

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