Temporal and multiple scale spatial variation in juvenile and adult abundance of the brown alga Ascophyllum nodosum

Åberg, Per; Pavia, Henrik

doi:10.3354/meps158111

Cited by 65 publications

(68 citation statements)

References 22 publications

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“…zone can be up to 100 m wide. At Tjärnö the vertical distribution of A. nodosum is restricted to 0.1 to 0.5 m below the mean water level because of the limited tidal range, and thus the width of the A. nodosum zone is usually < 0.5 m and rarely >2 m. Despite these differences, the total abundance and mean size of A. nodosum plants within the narrow belts at Tjärnö are similar to those in the mid-intertidal zone on the Isle of Man (Åberg & Pavia 1997).…”

Section: Methodsmentioning

confidence: 84%

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Effects of density on the vital rates of a modular seaweed

Viejo

Åberg²

2001

Mar. Ecol. Prog. Ser.

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The effects of density on the vital rates of the modular seaweed Ascophyllum nodosum (L.) Le Jol. were investigated in 2 areas of the northern Atlantic Ocean: the Isle of Man, in the Irish Sea, and Tjärnö, on the Swedish west coast. The densities of plants (genets) were manipulated in the field. The impact of density on survival, growth and reproduction of plants > 2 cm was estimated over 1 yr. Percentage survival of A. nodosum was high and apparently density-independent. This result is in accordance with other studies in land and marine systems where low mortality after establishment appears common and overpopulation is avoided by a balance in module density. The growth of A. nodosum was negatively density-dependent. The response of the modules (shoots) within plants was asymmetrical. Furthermore, the inception of new shoots was enhanced at low densities on the Isle of Man. Apart from intraspecific competition, other density-dependent processes affected the performance of the alga: the probability of breakage to smaller sizes increased with density in the Swedish area. As a result, the impact of density on the net plant growth was more patent at Tjärnö than on the Isle of Man. In relation to reproduction, the results of this study suggest a positive effect of density on the annual reproductive effort of the alga. Nevertheless, the manipulation was carried out after the initiation of reproductive structures. Increasing density clearly reduced plant growth, and reproduction is size-dependent in A. nodosum. This indicates that, in successive reproductive periods, reproduction may be negatively affected by density. In contrast to the results of another previous work, our study shows a negative impact of density on the net growth of A. nodosum and indicates the importance of module length structure in the demographical processes of the species. Not only the effect of density but also the significance of density dependence in the dynamics of the species probably vary in these areas with very different physical domains. KEY WORDS: Ascophyllum nodosum · Demography · Growth · Intraspecific competition · Rocky shoresResale or republication not permitted without written consent of the publisher

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Section: Methodsmentioning

confidence: 84%

“…These densities were within the natural range in those areas. The highest and lowest sampled densities (juveniles excluded) were, respectively, 55 and ) at Tjärnö (Åberg & Pavia 1997). Some transplanted plants were lost over the year.…”

Section: Methodsmentioning

confidence: 99%

Effects of density on the vital rates of a modular seaweed

Viejo

Åberg²

2001

Mar. Ecol. Prog. Ser.

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“…Another issue influencing reproductive capacity, which is still unknown for F. vesiculosus, is whether each conceptacle in F. vesiculosus always contains the same number of gametes, or whether this number is also dependent on temperature or other environmental factors. The only study quantifying the number of eggs per conceptacle in Fucales dealt with Ascophyllum nodosum (Åberg and Pavia 1997). In this species, the number of eggs per conceptacle did not vary among individuals, although the authors considered only one environmental setting.…”

Section: Reproduction Under Ocean Warming and Acidificationmentioning

confidence: 99%

Seasonal variations of Fucus vesiculosus fertility under ocean acidification and warming in the western Baltic Sea

et al. 2017

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Ocean warming and acidification may substantially affect the reproduction of keystone species such as Fucus vesiculosus (Phaeophyceae). In four consecutive benthic mesocosm experiments, we compared the reproductive biology and quantified the temporal development of Baltic Sea Fucus fertility under the single and combined impact of elevated seawater temperature and pCO 2 (1100 ppm). In an additional experiment, we investigated the impact of temperature (0-25°C) on the maturation of North Sea F. vesiculosus receptacles. A marked seasonal reproductive cycle of F. vesiculosus became apparent in the course of 1 year. The first appearance of receptacles on vegetative apices and the further development of immature receptacles of F. vesiculosus in autumn were unaffected by warming or elevated pCO 2 . During winter, elevated pCO 2 in both ambient and warmed temperatures increased the proportion of mature receptacles significantly. In spring, warming and, to a lesser extent, elevated pCO 2 accelerated the maturation of receptacles and advanced the release of gametes by up to 2 weeks. Likewise, in the laboratory, maturation and gamete release were accelerated at 15-25°C relative to colder temperatures. In summary, elevated pCO 2 and/or warming do not influence receptacle appearance in autumn, but do accelerate the maturation process during spring, resulting in earlier gamete release. Temperature and, to a much lesser extent, pCO 2 affect the temporal development of Fucus fertility. Thus, rising temperatures will mainly shift or disturb the phenology of F. vesiculosus in spring and summer, which may alter and/or hamper its ecological functions in shallow coastal ecosystems of the Baltic Sea.

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“…A large number of factors and interactions among them will create complex patterns in the distribution of organisms as well as variation of these patterns in time and space (e.g. Martin et al, 1993;Åberg & Pavia 1997;Airoldi, 2000). A basic knowledge of how natural processes and interactions generate variability of species in space and time is essential to predict how the deployment of defence structures will influence coastal assemblages and to identify sustainable design options.…”

Section: Biological Variation: Ecological Processes Vary In Time and mentioning

confidence: 99%

An ecological perspective on the deployment and design of low-crested and other hard coastal defence structures

Airoldi

Abbiati

Beck

et al. 2005

Coastal Engineering

338

166

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Coastal areas play a crucial role in the economical, social and political development of most countries; they support diverse and productive coastal ecosystems that provide valuable goods and services.Globally flooding and coastal erosion represent serious threats along many coastlines, and will become more serious as a consequence of human-induced changes and accelerated sea-level rise. Over the past indicate that the construction of coastal defence structures will affect coastal ecosystems. The consequences can be seen on a local scale, as disruption of surrounding soft-bottom environments and introduction of new artificial hard-bottom habitats, with consequent changes to the native assemblages of the areas. Proliferation of coastal defence structures can also have critical impacts on regional species diversity, removing isolating barriers, favouring the spread of non-native species and increasing habitat heterogeneity. Knowledge of the environmental context in which coastal defence structures are placed is fundamental to an effective management of these structures as, whilst there are some general consequences of such construction, many effects are site specific. Advice is provided to meet specific management goals, which include mitigating specific impacts on the environment, such as minimising changes to surrounding sediments, spread of exotic species or growth of nuisance species, and/or enhancing specific natural resources, for example enhancing fish recruitment or promoting diverse assemblages for ecoturism. The DELOS project points out that the downstream effects of defence structures on coastal processes and regional-scale impacts on biodiversity necessitate planning and management at a regional (large coastline) scale. To effectively understand and manage coastal defences, environmental management goals must be clearly stated and incorporated into the planning, construction, and monitoring stages.

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Temporal and multiple scale spatial variation in juvenile and adult abundance of the brown alga Ascophyllum nodosum

Cited by 65 publications

References 22 publications

Effects of density on the vital rates of a modular seaweed

Effects of density on the vital rates of a modular seaweed

Seasonal variations of Fucus vesiculosus fertility under ocean acidification and warming in the western Baltic Sea

An ecological perspective on the deployment and design of low-crested and other hard coastal defence structures

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