Wind dispersal of nodding thistle seeds and pappi

Kelly, Dave; Cameron, H. R.; Alex, J. F.

doi:10.30843/nzpp.1988.41.9853

Cited by 7 publications

(5 citation statements)

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“…In both species, seeds are wind dispersed, but because the pappus is easily detached, dispersal is limited to within a few tens of meters of the parent plant, although some small proportion of seed will be dispersed over much longer distances (Carlina: Greig- Smith and Sagar 1981;Klinkhamer et al 1996;Lofgren et al 2000;Franzen and Eriksson 2003;Carduus: Lee 1977;Smith and Kok 1984;Kelly et al 1988). In Carduus, gene flow via pollen dispersal has also been quantified, and this appears to occur over shorter distances than seed dispersal (Smyth and Hamrick 1987).…”

Section: Data On Seed Persistence and Dispersalmentioning

confidence: 99%

Seed Dormancy and Delayed Flowering in Monocarpic Plants: Selective Interactions in a Stochastic Environment

Rees¹,

Childs²,

Metcalf³

et al. 2006

The American Naturalist

105

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We explore the effects of temporal variation in multiple demographic rates on the joint evolution of delayed reproduction and seed dormancy using integral projection models (IPMs). To do this, we extend the standard IPM to include a discrete state variable representing the number of seeds in the seed bank, density-dependent recruitment, and temporal variation in demography. Parameter estimates for Carlina vulgaris and Carduus nutans are obtained from long-term studies. Carlina is relatively long lived and has a short-lived seed bank, whereas most Carduus plants flower in their first year and the seed bank is long lived. Using the evolutionarily stable strategy (ESS) approach, we predict the observed flowering and germination strategies. There is excellent agreement between the predictions and the field observations. The effects of temporal variation on the joint ESS are partitioned into components arising from nonlinear averaging (systematic changes in the mean resulting from the interaction between variability and nonlinearity) and nonequilibrium dynamics (fluctuations in fitness caused by temporal variation). This shows that temporal variation can have substantial effects on the observed flowering and germination strategies and that covariance between demographic processes is important. We extend the models to include spatial population structure and assess the robustness of the results from the nonspatial models.

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Section: Data On Seed Persistence and Dispersalmentioning

confidence: 99%

Seed Dormancy and Delayed Flowering in Monocarpic Plants: Selective Interactions in a Stochastic Environment

Rees¹,

Childs²,

Metcalf³

et al. 2006

The American Naturalist

105

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“…However, it has spread to, and has become common in, Canada, the United States, Australia, and New Zealand. In the latter two countries, it is still spreading and has not yet reached all suitable habitats (Kelly et al 1988, Sindel 1991. In New Zealand, C. nutans has been a serious weed for the last 40 yr (Popay and Thompson 1980, Jessep 1989, Wardle et al 1992, and has been recorded as covering up to 59% of the ground (Kelly and Popay 1985), causing considerable economic damage to grazing lands.…”

Section: The Species: Carduus Nutansmentioning

confidence: 99%

“…Carduus nutans does not reproduce vegetatively. Seeds are wind dispersed, but the pappus detaches easily and seeds are rarely blown more than a few meters from the parent plant (Kelly et al 1988). Other dispersal mechanisms also exist: seeds can be transported by water, birds, farm animals and vehicles, and, on larger scales, as a contaminant of agricultural seed (Medd and Smith 1978).…”

Section: The Species: Carduus Nutansmentioning

confidence: 99%

Estimating Biocontrol Agent Impact with Matrix Models: Carduus nutans in New Zealand

Shea¹,

Kelly²

1998

Ecological Applications

142

221

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We demonstrate the use of matrix models to assess the impact of biological control and other pest management strategies with a case study of Carduus nutans (nodding thistle) in New Zealand. Modeling can facilitate the choice of the best control agents, improve evaluation of biocontrol attempts, and assist in the design of integrated pest management plans.Field data for ϳ8000 mapped C. nutans plants at two sites in New Zealand were used to develop size-structured matrix models. The matrix models confirm that both populations of C. nutans were increasing in number, as is expected of a noxious weed in its invasion phase. Elasticity analysis indicated that seed/seedling and small-plant/seed transitions were more crucial to population growth than rosette survival rates. However, simulations of attack by the biocontrol agent Rhinocyllus conicus (nodding thistle receptacle weevil) showed that seed losses of ϳ69% would be required to make the populations decrease in size, far more than the observed losses of 30-40% in New Zealand, the United States, and Canada. This result accords with field observations of control failure in New Zealand, but not with records of successful control in North America.Other management possibilities, including the use of grazing management to suppress germination and an integrated weed management approach, were also assessed, using both deterministic and stochastic matrix models. This work indicates that, with continued suppression of germination in conjunction with a reduction of the input to the seed bank, it may be possible to control C. nutans in New Zealand.

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“…Other factors may also be operating since nodding thistle seedlings require gaps to establish (Panetta & Wardle, 1992) and are likely to demonstrate greater seedling emergence in weakened pasture. The majority of thistle seeds are not dispersed far from the parent plant (Kelly et al, 1988) and there is likely to be a very high density of thistle seeds in areas where pasture has been weakened by the thistle. This, combined with allelopathic (stimulatory and inhibitory) interactions between thistle seeds in close proximity (Wardle et al, 1991), also provides possible evidence for such a strategy operating.…”

Section: Differential Responses Of Test Speciesmentioning

confidence: 99%

Influence of plant age on the allelopathic potential of nodding thistle (Carduus nutans L.) against pasture grasses and legumes

Wardle¹,

Nicholson²,

Rahman³

1993

Weed Research

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Summary: Résumé: Zusammenfassung The allelopathic influence of four developmental stages of nodding thistle (small rosette, large rosette, bolting and dead plants) on eleven test species (six grasses, four legumes and itself) was investigated using aqueous extract bioassays, aqueous leachate bioassays, and bioassays based on addition of ground material to soil. The aqueous extract and leachate bioassays indicated that nodding thistle was most allelopathic at the rosette stages, while the bioassays involving amendment of soil with thistle tissue showed bolting live and dead plants to be the most allelopathic. It is proposed that nodding thistle is allelopathic at two phases of its development, i.e. at the early bolting stage when the larger rosette leaves are decomposing and releasing soluble inhibitors, and at the stage when bolting plants are dying and releasing insoluble inhibitors. Nodding thistle seedlings appear to be stimulated by addition of thistle tissues to soil, indicating that thistle plants may weaken pasture and simultaneously encourage recruitment of its own species. This is consistent with previous studies detecting high densities of thistle seedlings in the vicinity of deceased parent plants. The six grass species were generally more tolerant to thistle allelopathic effects than were the four legume species, but no consistent differences emerged between different grass or legume species. Influence de l'age de la plante sur le potentiel allélopathique du chardon penche (Carduus nutans L.) vis a vis des prairies de graminées et de légumineuses L'influence allélopathique de 4 stades de développement du chardon penché (petite rosette, grande rosette, montaison, plantes mortes) sur 11 espèces tests (6 graminées, 4 légumineuses et lui‐même) a étéétudiée en utilisant des bioessais d'extraction acqueuse, des bioessais de lessivage acqueux et des bioessais fondés sur l'addition au sol d'amendement. Les bioessais d'extraction acqueuse et de lessivage ont montré que le chardon penchéétait plus allélopathique au stade rosette tandis que les bioessais impliquant l'amendement de sol avec des tissues de chardon ont montré que la montaison et les plantes mortes étaient les plus allélopathiques. Il est proposé que le chardon penché est allélopathique à 2 phases de son développement, par exemple au stade montaison précoce quand les plus grandes feuilles de la rosette se décomposent et relachent les inhibiteurs solubles, et au stade où les plantes montées meurent et relächent les inhibiteurs insolubles. Les plantules de chardon penché apparaissent être stimulées par l'addition de tissus de chardon au sol, montrant que les plantes de chardon peuvent affaiblir une prairie et simultanément favoriser sa propre réimplantation. Ceci est conforme avec des études précédentes montrant des fortes densités de plantules de chardon au voisinage de plantes parentes mortes. Les 6 espèces de graminées ont été de façon générale plus tolérantes aux effets allélopathiques que les 4 espèces de légumineuses, mais aucune différence imp...

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Wind dispersal of nodding thistle seeds and pappi

Cited by 7 publications

References 0 publications

Seed Dormancy and Delayed Flowering in Monocarpic Plants: Selective Interactions in a Stochastic Environment

Seed Dormancy and Delayed Flowering in Monocarpic Plants: Selective Interactions in a Stochastic Environment

Estimating Biocontrol Agent Impact with Matrix Models: Carduus nutans in New Zealand

Influence of plant age on the allelopathic potential of nodding thistle (Carduus nutans L.) against pasture grasses and legumes

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