Symmetry of Below-Ground Competition between Kochia scoparia Individuals

Weiner, Jacob; Wright, Daniel B.; Castro, Scott

doi:10.2307/3546093

Cited by 112 publications

(85 citation statements)

References 18 publications

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“…The diminishing of the number and growth of above-ground units in a crowded environment observed in herbaceous species was also recorded in trees (Canham et al 2004). Additionally, it is worth mentioning that competition from neighbours for below-ground resources may force the allocation of biomass to roots at the expense of the shoot (Weiner et al 1997).…”

Section: Discussionmentioning

confidence: 97%

The variability of Gentiana pneumonanthe L. subpopulations in different habitat conditions

Kostrakiewicz-Gierałt

2016

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Abstract. The impact of habitat conditions on the spatio-temporal variability of abundance and structure of subpopulations of Gentiana pneumonanthe L. was investigated in the years 2013-2015 in patches of abandoned Molinion caeruleae meadows in different stages of successional overgrowing (Patches I-III), as well as in a patch of willow thickets (Patch IV). The height of the standing vegetation and soil humidity increased in successive patches, while the light intensity at ground level diminished gradually. Performed observations showed that abundance of subpopulations decreased from Patch I to Patch IV. Seedlings, juvenile and dormant individuals were not found in all subpopulations, whereas the share of vegetative and generative adults differed significantly. The total number of above-ground units per individual, as well as the height of vegetative stems, increased in consecutive years; moreover, it augmented from Patch I to Patch III and it diminished in Patch IV. The height of flowering stalks rose in consecutive years and in successive patches. The numbers of flowers and fruits in consecutive years were rather constant, whilst in successive study sites they augmented gradually. In light of the performed studies, it might be concluded that the subpopulation occurring in Patch I presents the best state, whereas the subpopulation occurring in Patch IV shows the worst condition and, in the near future, might be eliminated from the colonised site.

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Section: Discussionmentioning

confidence: 97%

The variability of Gentiana pneumonanthe L. subpopulations in different habitat conditions

Kostrakiewicz-Gierałt

2016

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“…This species was chosen because its biomass can be estimated very accurately from non-destructive, non-invasive measurements such as stem diameter, height and total branch length, and the relationship between these non-destructive measures and biomass is not altered by the competitive environment (Weiner & Fishman 1994;Weiner et al . 1997).…”

Section: Methodsmentioning

confidence: 99%

Competitive effect is a linear function of neighbour biomass in experimental populations of Kochia scoparia

Ramseier¹,

Weiner²

2005

Journal of Ecology

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Summary1 Neighbour size and distance are confounded in most studies of plant growth and competition at the individual level. To investigate the effects of neighbour size on competitive effect, we grew target Kochia scoparia individuals surrounded by six equidistant, even-aged conspecific neighbours. We varied neighbour size by sowing groups of neighbours at different times, and we also varied the sowing time of the target plants to generate variation in both neighbour and target size during the process of competition. We analysed the growth of target plants over two time intervals as a function of their own size and the size of their neighbours at the beginning of the interval. 2 When competition became intense, the relative growth rate of target plants was primarily determined by the size of their neighbours. There was a negative linear relationship between the relative growth rate of target plants over an interval and the biomass of their neighbours at the beginning of the interval. The size of the target plant itself did not make a significant additional contribution to predicting its growth rate. There is a limit on the growth in biomass of the population (target + neighbours), and growth of individuals occurs within this constraint. Local biomass density, which can be primarily determined by neighbouring individuals, can be much more important for an individual's growth than its own size. 3 There was no evidence of size-asymmetric competition. The size of neighbours was the primary determinant of a target plant's relative growth rate, but the effect of a given amount of neighbour biomass was the same for neighbours larger and those smaller than the target plant.

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“…Most of the competition experiments have been carried out under homogeneous conditions and some studies have shown that smaller plants (individuals) have a competitive advantage when compared with their larger neighbour (e.g., Newberry & Newman 1978;Weiner et al 1997). The results published by indicate that heterogeneity alone, without a change in the overall nutrient availability of the soil, can change the relative competitive ability of two perennial plant species.…”

Section: Introductionmentioning

confidence: 99%

Soil nutrient heterogeneity and competitive ability of three grass species (Festuca ovina, Arrhenatherum elatius and Calamagrostis epigejos) in experimental conditions

2009

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Abstract:We studied the effects of differences in root growth and nutrient pool on the competitive ability of Festuca ovina (short grass), Arrhenatherum elatius and Calamagrostis epigejos (tall grasses) grown in monocultures and in mixtures of homogeneous and heterogeneous environments during two growing seasons. Analysis of variance revealed a significant effect of plant species on nutrient concentrations in above-ground biomass and of substrate type on contents of N, K, Ca, Mg in biomass. The ANOVA also confirmed the significant effect of competitive environment on the concentration of N, K in above-ground biomass. In heterogeneous environments, both tall grasses (in competition with F. ovina) were able to produce more roots in the nutrient-rich patches and to accumulate more nitrogen in plant tissues, which was associated with higher yield of their above-ground biomass. Thus, the relative competitive ability for nutrients of both tall grasses was higher than that of F. ovina. This competitive ability of A. elatius to C. epigejos increased in heterogeneous treatments.

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Symmetry of Below-Ground Competition between Kochia scoparia Individuals

Cited by 112 publications

References 18 publications

The variability of Gentiana pneumonanthe L. subpopulations in different habitat conditions

The variability of Gentiana pneumonanthe L. subpopulations in different habitat conditions

Competitive effect is a linear function of neighbour biomass in experimental populations of Kochia scoparia

Soil nutrient heterogeneity and competitive ability of three grass species (Festuca ovina, Arrhenatherum elatius and Calamagrostis epigejos) in experimental conditions

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