Analysis of Frequency and Density Effects on Growth in Mixtures of Salvia Splendens and Linum Grandiflorum Using Hexagonal Fan Designs

Antonovics, Janis; Fowler, Norma L.

doi:10.2307/2259779

Cited by 52 publications

(37 citation statements)

References 20 publications

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“…Linum grandiflorum (LR) is a winter annual, that is typically highly branched, has a slender stem, has numerous, small, alternately arranged leaves and a terminal branched inflorescence, and reaches heights of 20–50 cm (Munz 1974; Antonovics & Fowler 1985). It flowers from March to June (Wills & Irwin 1961).…”

Section: Methodsmentioning

confidence: 99%

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂

Berntson

Rajakaruna

Bazzaz

1998

Global Change Biology

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Rising levels of atmospheric CO2 may alter patterns of plant biomass production. These changes will be dependent on the ability of plants to acquire sufficient nutrients to maintain enhanced growth. Species‐specific differences in responsiveness to CO2 may lead to changes in plant community composition and biodiversity. Differences in species‐level growth responses to CO2 may be, in a large part, driven by differences in the ability to acquire nutrients. To understand the mechanisms of how elevated CO2 leads to changes in community‐level productivity, we need to study the growth responses and patterns of nutrient acquisition for each of the species that comprise the community. In this paper, we present a study of how elevated CO2 affects community‐level and species‐level patterns of nitrogen uptake and biomass production. As an experimental system we use experimental communities of 11 co‐occurring annuals common to disturbed seasonal grasslands in south‐western U.S.A. We established experimental communities with approximately even numbers of each species in three different atmospheric CO2 concentrations (375, 550, and 700 ppm). We maintained these communities for 1, 1.5, and 2 months at which times we applied a 15N tracer (15NH415NO3) to quantify the nitrogen uptake and then measured plant biomass, nitrogen content, and nitrogen uptake rates for the entire communities as well as for each species. Overall, community‐level responses to elevated CO2 were consistent with the majority of other studies of individual‐ and multispecies assemblages, where elevated CO2 leads to enhanced biomass production early on, but this enhancement declines through time. In contrast, the responses of the individual species within the communities was highly variable, showing the full range of responses from positive to negative. Due to the large variation in size between the different species, community‐level responses were generally determined by the responses of only one or a few species. Thus, while several of the smaller species showed trends of increased biomass and nitrogen uptake in elevated CO2 at the end of the experiment, community‐level patterns showed a decrease in these parameters due to the significant reduction in biomass and nitrogen content in the single largest species. The relationship between enhancement of nitrogen uptake and biomass production in elevated CO2 was highly significant for both 550 ppm and 700 ppm CO2. This relationship strongly suggests that the ability of plants to increase nitrogen uptake (through changes in physiology, morphology, architecture, or mycorrhizal symbionts) may be an important determinant of which species in a community will be able to respond to increased CO2 levels with increased biomass production. The fact that the most dominant species within the community showed reduced enhancement and the smaller species showed increased enhancement suggest that through time, elevated CO2 may lead to significant changes in community composition. At the community level, nitrogen uptake r...

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Section: Methodsmentioning

confidence: 99%

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂

Berntson

Rajakaruna

Bazzaz

1998

Global Change Biology

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“…If the outcome of competition is frequency-dependent, then the more common competitor can win over the less common one even in a uniform environment. An example is mixtures of Salvia spendens with Linum grandiflorum, where the initially more common plant excludes the other in pot experiments (Antonovics & Fowler 1985). Frequency-dependent competition between M. oreophila and M. pulvinaris could have a strongly stabilizing effect on the spatial boundary between the two species.…”

Section: What Sets the Range Limits Of M Oreophila?mentioning

confidence: 99%

What limits a rare alpine plant species? Comparative demography of three endemic species of Myosotis (Boraginaceae)

et al. 2007

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Establishing what are the underlying causes of species range limits is of fundamental interest in ecology. We followed the fate of individually mapped plants of three endemic New Zealand high-alpine species of Myosotis, over a period of 9 years. The species provide contrasts in their geographical range and their demography. Myosotis oreophila Petrie is rare and extremely localized (c. 0.5 ha extent), Myosotis cheesemanii Petrie is regionally endemic, and Myosotis pulvinaris Hook. f. is more widespread. All three occur on the Dunstan Mountains, Central Otago, South Island, New Zealand within a 1-km radius, and individual plants were followed in four permanent plots. The three species differed in their longevity and in population variability, with the most widespread species (M. pulvinaris) having the lowest survival (61% per year), the fewest old plants (only 3% of plants present in 1993 surviving until 2001), no increase in survival rates with age, and the most variability in total numbers across years. Both of the rare species, M. oreophila and M. cheesemanii, had higher survival (75% and 88%, respectively, per year) especially for older plants, many older plants (20% and 59%, respectively, of 1993 plants surviving until 2001), and lower variability in total numbers across years. These results are consistent with other studies showing that rare plant species tend to have higher inertia than more common congeners. The range limits of M. oreophila showed a high level of spatial constancy on a scale of metres over the 9 years, despite 80% turnover in plants during that time. The M. oreophila population showed lower mean densities of plants near to the population boundaries, identical age-specific survival rates, but lower flowering probabilities, than the core of the population. We were unable to detect any abiotic differences between inside and outside the M. oreophila range in terms of topography, soil parent materials, microclimate or through manipulation of snow cover. Disturbance may be a factor affecting the distribution of M. cheesemanii but limiting factors for M. oreophila and M. pulvinaris are likely to be biotic (competition, seed limitation, dispersal capacity) and/or historic. Further experimentation is recommended.

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“…Antonovics and Fowler (1985) used a ''hexagonal fan'' experimental design, in which plants of two species were placed at increasing distances from each other in two overlapping hexagonal arrays. Antonovics and Fowler (1985) used a ''hexagonal fan'' experimental design, in which plants of two species were placed at increasing distances from each other in two overlapping hexagonal arrays.…”

Section: Review Of Experimental Designs: Uses and Objectivesmentioning

confidence: 99%

Response Surface Experimental Designs for Investigating Interspecific Competition

Inouye

2001

Ecology

228

161

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Competition is an important interaction in ecology, and many experiments have been done to examine the effects of intraspecific and interspecific competition. Unfortunately, most of these experiments have been done using either substitution or additive experimental designs. Substitution designs, and to a lesser extent additive designs, severely limit the useful inferences that ecologists can draw from the resulting data. Response surface experimental designs, which vary the densities of two competing species independently, offer the advantage of being able to compare the fits of alternative competition models and to estimate model parameters. This kind of experimental design has been relatively little used in ecology to date. I consider the use of response surface designs from two perspectives. The first is the optimal allocation of experimental effort among density treatments, with the goal of distinguishing among alternative models. Second, I compare the ability of six response surface designs to estimate known competition coefficients correctly, using simulated data. Low densities and densities near equilibrium in one generation tend to return similar densities the following generation and thus provide little or no information for comparing alternative population models. Experimental designs that span a wide range of densities, including high densities above carrying capacities, provide more accurate parameter estimates in general, but low densities are helpful for estimating population growth rates. Designs that are not fully factorial are one compromise solution that can yield accurate parameter estimates for models and yet require less experimental effort than full factorial surfaces. In general, response surfaces are a powerful class of experimental design and offer potentially stronger connections between empirical and theoretical approaches than traditional experimental designs.

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Analysis of Frequency and Density Effects on Growth in Mixtures of Salvia Splendens and Linum Grandiflorum Using Hexagonal Fan Designs

Cited by 52 publications

References 20 publications

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂

What limits a rare alpine plant species? Comparative demography of three endemic species of Myosotis (Boraginaceae)

Response Surface Experimental Designs for Investigating Interspecific Competition

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Analysis of Frequency and Density Effects on Growth in Mixtures of Salvia Splendens and Linum Grandiflorum Using Hexagonal Fan Designs

Cited by 52 publications

References 20 publications

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO2

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO2

What limits a rare alpine plant species? Comparative demography of three endemic species of Myosotis (Boraginaceae)

Response Surface Experimental Designs for Investigating Interspecific Competition

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Product

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Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂

Growth and nitrogen uptake in an experimental community of annuals exposed to elevated atmospheric CO₂