Recovery of the brown alga Fucus gardneri following a range of removal intensities

Speidel, Markus O.; Harley, Christopher D. G.; Wonham, Marjorie J.

doi:10.1016/s0304-3770(01)00191-7

Cited by 20 publications

(19 citation statements)

References 25 publications

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“…However, it is still common practice in experimental disturbance studies to substitute disturbance intensity by its eVects (e.g. percentage of population removal; Speidel et al 2001) or to use a constant value over the duration of a perturbation (e.g. James et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Temporal variability within disturbance events regulates their effects on natural communities

Molinos

Donohue

2011

Oecologia

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Disturbances are processes inherently variable in time and space. This variability comprises a key determinant of ecosystem responses to disturbance. Temporal patterns can, however, vary significantly both among and within individual disturbance events. While recent research has demonstrated an importance of the former, studies on the effects of variability within perturbations have consistently confounded temporal variability with other disturbance attributes (e.g. overall intensity or duration). We established a field experiment to test explicitly the hypothesis that the temporal pattern within perturbations can drive ecosystem responses independently of other disturbance traits. We examined the effects of two disturbance regimes comprising sediment pulses of contrasting temporal pattern (constant and temporally variable intensities) on the benthic invertebrate assemblage of a headwater stream. The overall intensity, duration, timing and frequency of the perturbations were, however, identical. Invertebrates drifting during the temporally variable pulses were more abundant and differed in taxonomic and trophic structure than those exposed to constant perturbations. Moreover, whereas temporal patterns of disturbance events had no immediate effect on benthic invertebrate assemblages in situ, assemblages exposed to the constant perturbations took longer to recover from sediment disturbances than those exposed to temporally variable perturbations. Our results demonstrate that variability in the temporal pattern of intensity within individual perturbations can regulate, independently of other disturbance attributes, the extent and type of ecosystem responses to, and recovery from, disturbances. Effective environmental management and policy therefore necessitate the explicit quantification of temporal patterns of intensity both within and among perturbations.

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Section: Discussionmentioning

confidence: 99%

Temporal variability within disturbance events regulates their effects on natural communities

Molinos

Donohue

2011

Oecologia

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“…In some cases, the behavior of the system may not change over a wide range of progressive impairment (e.g., biomass removal or species loss), only to shift suddenly once a threshold is crossed (Speidel et al. , Davies et al. ).…”

Section: Shifts In Community Structure and Ecosystem Functionmentioning

confidence: 99%

Effects of Climate Change on Global Seaweed Communities

Harley

Anderson

Demes

et al. 2012

Journal of Phycology

547

414

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Seaweeds are ecologically important primary producers, competitors, and ecosystem engineers that play a central role in coastal habitats ranging from kelp forests to coral reefs. Although seaweeds are known to be vulnerable to physical and chemical changes in the marine environment, the impacts of ongoing and future anthropogenic climate change in seaweed-dominated ecosystems remain poorly understood. In this review, we describe the ways in which changes in the environment directly affect seaweeds in terms of their physiology, growth, reproduction, and survival. We consider the extent to which seaweed species may be able to respond to these changes via adaptation or migration. We also examine the extensive reshuffling of communities that is occurring as the ecological balance between competing species changes, and as top-down control by herbivores becomes stronger or weaker. Finally, we delve into some of the ecosystem-level responses to these changes, including changes in primary productivity, diversity, and resilience. Although there are several key areas in which ecological insight is lacking, we suggest that reasonable climate-related hypotheses can be developed and tested based on current information. By strategically prioritizing research in the areas of complex environmental variation, multiple stressor effects, evolutionary adaptation, and population, community, and ecosystem-level responses, we can rapidly build upon our current understanding of seaweed biology and climate change ecology to more effectively conserve and manage coastal ecosystems.

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“…Large variations in recruitment of S. alveolata were documented over periods up to years (Gruet ), a time‐scale which is clearly larger than the longest time for recovery available to this species to recolonize after disturbance in the present experiment. Analogously, there is evidence that even considerably damaged beds of canopy‐forming algae may recover in some months, but large patches where the canopy was completely removed by very intense disturbance take much longer (Underwood ; Speidel, Harley & Wonham ). In this context, but in the opposite direction, the main positive response of encrusting coralline algae to disturbance intensity is consistent with their described poor competitive abilities and great resistance to physical stress (Breitburg ).…”

Section: Discussionmentioning

confidence: 99%

Compounded perturbations in coastal areas: contrasting responses to nutrient enrichment and the regime of storm‐related disturbance depend on life‐history traits

Bertocci

Godino

Freitas³

et al. 2017

Functional Ecology

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Summary Natural systems are exposed to compounded perturbations, whose changes in temporal variance can be as important as those in mean intensity for shaping the structure of assemblages. Specifically, climate‐related physical disturbances and nutrient inputs due to natural and/or anthropogenic activities occur concomitantly, but experimental tests of the simultaneous effects of changes in the regime of more than one perturbation are generally lacking. Filling this gap is the key to understand ecological responses of natural assemblages to climate‐related change in the intensity and temporal patterning of physical disturbance combined with other global stressors. Responses to factorial manipulations of nutrient enrichment, mean intensity and temporal variability in storm‐like mechanical disturbance were examined, using benthic assemblages of tide‐pools as model system. Response variables were mean abundance values and temporal variances of taxa with different life‐traits. Consistent negative effects of disturbance intensity were observed for the mean cover of long‐living taxa (algal canopies and the polychaete Sabellaria alveolata), whose temporal fluctuations were also reduced by more severe mechanical stress. More resilient taxa (ephemeral algae, mostly green of the genus Ulva) increased under enriched conditions, particularly when low‐intensity events were irregularly applied over time. Opposite effects of disturbance intensity depending on nutrient availability occurred on filamentous algae (e.g. red of the genus Ceramium). This was probably due to the fact that, although nutrient enrichment stimulated the abundance of both algal groups, when this condition was combined with relatively mild physical disturbance the competitively superior ephemeral green algae tended to become dominant over filamentous red algae. The same did not occur under high intensity of disturbance since it likely damaged large, foliose fronds of Ulva‐like forms more than small, filamentous fronds of Ceramium‐like forms. Grazers were positively affected by nutrients, likely responding indirectly to more food available. A direct relationship between the mean abundance of most organisms and their temporal fluctuations was documented. However, all organisms persisted throughout the study, even under experimental conditions associated to the largest temporal variation in their abundance, likely due to their ability to resist to/quickly recover from, the applied perturbations. Therefore, in systems with great recovery abilities of dominant organisms (e.g. rocky intertidal, grasslands), effects of traits of the regime of disturbance and nutrient enrichment may modulate the fluctuations of populations not through the elimination and substitution of species, but through changes in relative abundances of the same species. This contrasts with the theory that temporal variation in abundance would be directly related to the risk of local extinction. Present findings enable more accurate predictions of the consequences of climatic and non‐climatic...

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Recovery of the brown alga Fucus gardneri following a range of removal intensities

Cited by 20 publications

References 25 publications

Temporal variability within disturbance events regulates their effects on natural communities

Temporal variability within disturbance events regulates their effects on natural communities

Effects of Climate Change on Global Seaweed Communities

Compounded perturbations in coastal areas: contrasting responses to nutrient enrichment and the regime of storm‐related disturbance depend on life‐history traits

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