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Morgan S Pratchett - One of the best experts on this subject based on the ideXlab platform.

  • Trade-offs associated with dietary specialization in corallivorous butterflyfishes (Chaetodontidae: Chaetodon)
    Behavioral Ecology and Sociobiology, 2007
    Co-Authors: Michael L. Berumen, Morgan S Pratchett
    Abstract:

    Increasing dietary specialization is an inherently risky strategy because it increases a species’ vulnerability to resource depletion. However, risks associated with dietary specialization may be offset by increased performance when feeding on preferred prey. Although rarely demonstrated, highly specialized species are expected to outperform generalists when feeding on their preferred prey, whereas generalists are predicted to have more similar performance across a range of different prey. To test this theory, we compared the growth rates of two obligate coral-feeding butterflyfishes (Chaetodon trifascialis and Chaetodon plebeius) maintained on exclusive diets of preferred vs nonpreferred prey. In the field, C. trifascialis was the most specialized species, feeding almost exclusively on just one coral species, Acropora Hyacinthus. C. plebeius meanwhile, was much less specialized, but fed predominantly on Pocillopora damicornis. During growth experiments, C. trifascialis grew fastest when feeding on A. Hyacinthus and did not grow at all when feeding on less preferred prey (P. damicornis and Porites cylindrica). C. plebeius performed equally well on both A. Hyacinthus and P. damicornis (its preferred prey), but performed poorly when feeding on P. cylindrica. Both butterflyfishes select coral species that maximize juvenile growth, but contrary to expectations, the more specialized species (C. trifascialis) did not outperform the generalist species (C. plebeius) when both consumed their preferred prey. Increased dietary specialization, therefore, appears to be a questionable strategy, as there was no evidence of any increased benefits to offset increases in susceptibility to disturbance.

  • dietary selection by coral feeding butterflyfishes chaetodontidae on the great barrier reef australia
    2007
    Co-Authors: Morgan S Pratchett
    Abstract:

    This study explored dietary selection among 14 species of coral-feeding butterflyfishes at Lizard Island in the Northern Great Barrier Reef, Australia. All 14 butterflyfishes studied (Chaetodon aureofasciatus, C. baronessa, C. citrinellus, C. kleinii, C. lunula, C. lunulatus, C. melannotus, C. plebeius, C. rafflesii, C. rainfordi, C. speculum, C. trifascialis, C. ulietensis and C. unimaculatus) exhibited significant dietary selection, consuming one or more coral species disporportionately to their availability. The most selective of these butterflyfishes was C. trifascialis, which selectively consumed Acropora corals (especially A. Hyacinthus) to the exclusion of other prey corals. There were notable differences in the degree of selectivity exhibited among coral-feeding butterflyfishes, but there was a high degree of concordance in their apparent feeding preferences. Notably, most coral-feeding butterflyfishes predominantly selected A. Hyacinthus and secondarily Pocillopora damicornis. Observed selectivity in the dietary habits of coral-feeding butterflyfishes may influence their spatial and temporal patterns of abundance and is likely to be fundamental in determining their responses to major disturbances (e.g. climate-induced coral bleaching), which alter the availability of different corals.

  • dietary overlap among coral feeding butterflyfishes chaetodontidae at lizard island northern great barrier reef
    Marine Biology, 2005
    Co-Authors: Morgan S Pratchett
    Abstract:

    This study documented the range of corals, and other prey types, consumed by 20 species of butterflyfishes, which co-occur at Lizard Island, northern Great Barrier Reef, Australia. Six species (Chaetodon aureofasciatus, C. baronessa, C. lunulatus, C. plebius, C. rainfordi and C. trifascialis) fed almost exclusively on scleractinian corals, and a further eight species (C. citrinellus, C. kleinii, C. lunula, C. melannotus, C. rafflesi, C. speculum, C. ulietensis, and C. unimaculatus) took a significant proportion of their bites from corals. The other six species (C. auriga, C. ephippium, C. lineolatus, C. semeion, C. vagabundus, and Chelmon rostratus) rarely consumed coral, but fed on small discrete prey items from non-coral substrates. Coral-feeding butterflyfishes consumed a wide range of corals. Chaetodon lunulatus, for example, consumed 51 coral species from 24 different genera. However, there was up to 72% dietary overlap between coral-feeding butterflyfishes, with 11/14 species feeding predominantly on Acropora Hyacinthus or Pocillopora damicornis. The most specialised corallivore, C. trifascialis, took 88% of bites from A. Hyacinthus. Chaetodon trifascialis defend territories encompassing one or more colonies of A. Hyacinthus, and may have prevented other species such as C. lunulatus from feeding even more extensively on this coral. This study has shown that coexistence of coral-feeding butterflyfishes occurs despite an apparent lack of partitioning of prey resources. While different coral-feeding butterflyfishes were more or less selective in their use of different coral prey, virtually all species fed predominantly on A. Hyacinthus or P. damicornis.

  • within reef differences in diet and body condition of coral feeding butterflyfishes chaetodontidae
    Marine Ecology Progress Series, 2005
    Co-Authors: Michael L. Berumen, Morgan S Pratchett, Mark I Mccormick
    Abstract:

    Given the highly stochastic nature of larval supply, coral reef fishes often settle in suboptimal habitats with limited access to prey or other resources. Variation in the availability and quality of resources among different reef habitats is likely to have significant effects on the physiological condition and subsequent fitness of resident fishes, if not their absolute abundance. This study compared the abundance, feeding and condition of 2 species of coral-feeding butterflyfishes (Chaetodon baronessa and C. lunulatus) across contrasting habitats with markedly different prey availability. Despite differences in prey availability, densities of C. baronessa and C. lunulatus were very similar between locations. However, there was significant spatial variation in their feeding and physiological condition. In front-reef locations, where coral prey was highly abundant, C. baronessa fed preferentially and almost exclusively on the coral Acropora Hyacinthus. In contrast, in back-reef locations where coral prey was scarce and A. Hyacinthus lacking, C. baronessa was much less selective and consumed a wider range of coral prey. C. lunulatus was less selective than C. baronessa, but the diet of C. lunulatus also differed significantly between habitats. C. lunulatus consumed mostly A. Hyacinthus in front-reef locations but not in greater proportions than it was available. In back-reef locations, C. lunulatus preferentially consumed A. intermedia and Porites spp. The physiological condition of both C. baronessa and C. lunulatus was much worse in back-reef locations compared to front-reef locations, which may reflect differences in the quantity and/or quality of prey available in different habitats. This study suggests that small-scale (within-reef) differences in prey availability can have significant effects on the physiological condition and subsequent fitness of coral reef fishes.

Vives Miquel - One of the best experts on this subject based on the ideXlab platform.

Stephen R Palumbi - One of the best experts on this subject based on the ideXlab platform.

  • sub weekly coral linear extension measurements in a coral reef
    Journal of Experimental Marine Biology and Ecology, 2019
    Co-Authors: Lupita J Ruizjones, Stephen R Palumbi
    Abstract:

    Abstract Coral growth rates are often used as a metric of coral health and are measured extensively in the laboratory under controlled conditions to better understand the potential impacts of future climate change scenarios. However, in the field, corals live in dynamic environments, which can be subjected to multiple types of stressors that can not be mimicked in the laboratory. Furthermore, the temporal scales over which many environmental conditions can vary in the reef, such as extreme temperature anomalies, tidal fluctuations, and point source pollution events are far shorter than most field estimates of coral growth, which are generally at annual or seasonal scales. To measure the impact to coral growth of environmental variables that vary on time scales of less than a year or a few months requires developing new growth measurement techniques. With the goal of measuring coral growth at sub-weekly scales in the field, we developed a technique to measure 5-day linear extension growth rates. We tested our approach on colonies of Acropora Hyacinthus living in a shallow back-reef ecosystem with routine extreme daily fluctuations in temperature, pH, and dissolved oxygen saturation. Using serial skeletal staining and petrographic thin sectioning we measured linear extension in A. Hyacinthus during three consecutive 5-day growth periods that had differing amounts of environmental variability. At our field site in American Samoa, the second growth period had the largest tidal swings, resulting in higher variability: within a day temperature ranged up to 5.4 °C (reaching a maximum of 31.9 °C) and pH ranged up to 0.41 units (with a minimum of pH 7.78). We tested whether corals are able to maintain even linear extension rates across these short periods of time or not. After confocal microscopy analysis of stained skeletal samples we found that linear extension rates were similar across the three growth periods. Our fine-scale measurements suggest that during periods with different magnitudes of tidally driven environmental variability, but constant mean conditions, short-term linear extension growth rates remain consistent.

  • long term growth rates and effects of bleaching in acropora Hyacinthus
    Coral Reefs, 2018
    Co-Authors: Zachary Gold, Stephen R Palumbi
    Abstract:

    Understanding the response of coral growth to natural variation in the environment, as well as to acute temperature stress under current and future climate change conditions, is critical to predicting the future health of coral reef ecosystems. As such, ecological surveys are beginning to focus on corals that live in high thermal stress environments to understand how future coral populations may adapt to climate change. We investigated the relationship between coral growth, thermal microhabitat, symbionts type, and thermal acclimatization of four species of the Acropora Hyacinthus complex in back-reef lagoons in American Samoa. Coral growth was measured from August 2010 to April 2016 using horizontal planar area of coral colonies derived from photographs and in situ maximum width measurements. Despite marked intraspecific variation, we found that planar colony growth rates were significantly different among cryptic species. The highly heat tolerant A. Hyacinthus variant “HE” increased in area an average of 2.9% month−1 (0.03 cm average mean radial extension month−1). By contrast, the three less tolerant species averaged 6.1% (0.07 cm average mean radial extension month−1). Planar growth rates were 40% higher on average in corals harboring Clade C versus Clade D symbiont types, although marked inter-colony variation in growth rendered this difference nonsignificant. Planar growth rates for all four species dropped to near zero following a 2015 bleaching event, independent of the visually estimated percent area of bleaching. Within 1 yr, growth rates recovered to previous levels, confirming previous studies that found sublethal effects of thermal stress on coral growth. Long-term studies of individual coral colonies provide an important tool to measure impacts of environmental change and allow integration of coral physiology, genetics, symbionts, and microclimate on reef growth patterns.

  • early transcriptional responses during heat stress in the coral acropora Hyacinthus
    The Biological Bulletin, 2017
    Co-Authors: Nikki Traylorknowles, Noah H Rose, Elizabeth A Sheets, Stephen R Palumbi
    Abstract:

    Corals respond to heat pulses that cause bleaching with massive transcriptional change, but the immediate responses to stress that lead up to these shifts have never been detailed. Understanding these early signals could be important for identifying the regulatory mechanisms responsible for bleaching and how these mechanisms vary between more and less resilient corals. Using RNA sequencing (RNAseq) and sampling every 30 minutes during a short-term heat shock, we found that components of the transcriptome were significantly upregulated within 90 min and after a temperature increase of +2 °C. The developmental transcription factor, Kruppel-like factor 7, was highly expressed within 60 min, and stress-related transcription factors such as Elk-3 were highly expressed starting at 240 min. The sets of genes enriched for early transcriptional response to heat stress included heat shock proteins, small GTPases, and proteasome genes. Retrovirus-related Pol polyproteins from transposons were significantly expressed throughout the whole experiment. Lastly, we propose a model for early transcriptional regulation of protein degradation and cell adhesion response that may ultimately lead to the bleaching and stress response.

  • 33496_AHyacinthus_CoralContigs.fasta
    2016
    Co-Authors: Daniel J Barshis, Thomas A Oliver, Jason T. Ladner, François O. Seneca, Nikki Traylor-knowles, Stephen R Palumbi
    Abstract:

    Contigs with putative Cnidarian origin from a de novo transcriptome assembly of Acropora Hyacinthus. 16 individual A Hyacinthus adult colonies were exposed to control and elevated thermal exposures, mRNA was isolated and sequenced using the Illumina GA IIX platform, assembled, and resulting contigs were screened against known cnidarian databases for strong matches to isolate sequences likely to be coral in origin

  • 33496 Acropora Hyacinthus Contigs Annotation
    2016
    Co-Authors: François O. Seneca, Stephen R Palumbi
    Abstract:

    Annotations for the 33,496 contigs from Acropora Hyacinthus

Mikhail V. Matz - One of the best experts on this subject based on the ideXlab platform.

  • Acropora Hyacinthus Fst
    2016
    Co-Authors: Sarah W. Davies, Eric A. Treml, Carly D. Kenkel, Mikhail V. Matz
    Abstract:

    This is a csv file is a matrix with all pairwise Fst comparisons for Acropora Hyacinthus and all pairwise distances between islands

  • Acropora Hyacinthus structure
    2016
    Co-Authors: Sarah W. Davies, Eric A. Treml, Carly D. Kenkel, Mikhail V. Matz
    Abstract:

    This file contains all data for 12 loci for individuals assigned to Acropora Hyacinthus after initial clustering step. Data are formatted as structure input files

  • gene expression associated with white syndromes in a reef building coral acropora Hyacinthus
    BMC Genomics, 2015
    Co-Authors: Rachel M Wright, Galina V Aglyamova, Eli Meyer, Mikhail V. Matz
    Abstract:

    Corals are capable of launching diverse immune defenses at the site of direct contact with pathogens, but the molecular mechanisms of this activity and the colony-wide effects of such stressors remain poorly understood. Here we compared gene expression profiles in eight healthy Acropora Hyacinthus colonies against eight colonies exhibiting tissue loss commonly associated with white syndromes, all collected from a natural reef environment near Palau. Two types of tissues were sampled from diseased corals: visibly affected and apparently healthy. Tag-based RNA-Seq followed by weighted gene co-expression network analysis identified groups of co-regulated differentially expressed genes between all health states (disease lesion, apparently healthy tissues of diseased colonies, and fully healthy). Differences between healthy and diseased tissues indicate activation of several innate immunity and tissue repair pathways accompanied by reduced calcification and the switch towards metabolic reliance on stored lipids. Unaffected parts of diseased colonies, although displaying a trend towards these changes, were not significantly different from fully healthy samples. Still, network analysis identified a group of genes, suggestive of altered immunity state, that were specifically up-regulated in unaffected parts of diseased colonies. Similarity of fully healthy samples to apparently healthy parts of diseased colonies indicates that systemic effects of white syndromes on A. Hyacinthus are weak, which implies that the coral colony is largely able to sustain its physiological performance despite disease. The genes specifically up-regulated in unaffected parts of diseased colonies, instead of being the consequence of disease, might be related to the originally higher susceptibility of these colonies to naturally occurring white syndromes.

  • gene expression associated with white syndromes in a reef building coral acropora Hyacinthus
    bioRxiv, 2015
    Co-Authors: Rachel M Wright, Galina V Aglyamova, Eli Meyer, Mikhail V. Matz
    Abstract:

    Background Corals are capable of launching diverse immune defenses at the site of direct contact with pathogens, but the molecular mechanisms of this activity and the colony-wide effects of such stressors remain poorly understood. Here we compared gene expression profiles in eight healthy Acropora Hyacinthus colonies against eight colonies exhibiting tissue loss commonly associated with white syndromes, all collected from a natural reef environment near Palau. Two types of tissues were sampled from diseased corals: visibly affected and apparently healthy. Results Tag-based RNA-Seq followed by weighted gene co-expression network analysis identified groups of co-regulated differentially expressed genes between all health states (disease lesion, apparently healthy tissues of diseased colonies, and fully healthy). Differences between healthy and diseased tissues indicate activation of several innate immunity and tissue repair pathways accompanied by reduced calcification and the switch towards metabolic reliance on stored lipids. Unaffected parts of diseased colonies, although displaying a trend towards these changes, were not significantly different from fully healthy samples. Still, network analysis identified a group of genes, suggestive of altered immunity state, that were specifically up-regulated in unaffected parts of diseased colonies. Conclusions Similarity of fully healthy samples to apparently healthy parts of diseased colonies indicates that systemic effects of white syndromes on A. Hyacinthus are weak, which implies that the coral colony is largely able to sustain its physiological performance despite disease. The genes specifically up-regulated in unaffected parts of diseased colonies, instead of being the consequence of disease, might be related to the originally higher susceptibility of these colonies to naturally occurring white syndromes.

  • Results from ITS-1 454 NGS sequencing of Symbiodinium populations associated with Acropora colonies sampled from two sites in Palau.
    2014
    Co-Authors: Kate M. Quigley, Sarah W. Davies, Carly D. Kenkel, Mikhail V. Matz, Bette L. Willis, Line K. Bay
    Abstract:

    A. Variation in the proportion of haplotype 2 observed between two reef sites in Palau (Lighthouse reef (LH) and West Channel reef (WC)) for two species of corals, Acropora digitifera (A.d) and A. Hyacinthus (A.h). B. Regression showing how the relationship between the proportions of haplotypes 1 and 2 comprising Symbiodinium populations associated with Acropora digitifera and A. Hyacinthus (n = 6 for A.digitifera and n = 5 for A.Hyacinthus) varies among corals collected from two sites (WC and LH). C. Haplotype network for the two dominant haplotype clusters used as references visualized with two ITS-1 sequences from Genbank (Grey squares).

Pisapia Chiara - One of the best experts on this subject based on the ideXlab platform.

  • Geographically conserved rates of background mortality among common reef-building corals in Lhaviyani Atoll, Maldives, versus northern Great Barrier Reef, Australia
    'Springer Science and Business Media LLC', 2015
    Co-Authors: Pisapia Chiara, Sweet, Michael J., Sweatman Hugh, Pratchett Morgan
    Abstract:

    Even in the absence of major disturbances (e.g., cyclones and bleaching), corals are consistently subject to high levels of background mortality, which under-mines individual fitness and resilience of coral colonies. Most studies of coral mortality however only focus on catastrophic mortality associated with major acute disturbance events, neglecting to consider background levels of chronic mortality that have a significant influence on population structure and turnover. If, for example, there are geo-graphic differences in the prevalence of injuries and rates of background mortality, coral communities may vary in their susceptibility to acute large-scale disturbances and environmental change. This study quantified the prevalence and severity of partial mortality for four dominant and widespread coral taxa (massive Porites, encrusting Montipora, Acropora Hyacinthus,and branching Pocillopora) at Lhaviyani Atoll, Maldives, and on the northern Great Barrier Reef, Australia. The prevalence and severity of sublethal injuries varied greatly among taxa, but was generally similar between locations; on the Great Barrier Reef, 99.4 % Porites colonies, 66 % of A. Hyacinthus, and 64 % of Pocillopora had conspicuous injuries, compared to 92.4 % of Porites, 47.5 % of A. Hyacinthus, and 44 % of Pocillopora colonies in Lhaviyani Atoll. These results suggest that background rates of mortality and injury, and associated resilience of coral populations and communities to large-scale disturbances, are conserved at large geo-graphic scales, though adjacent colonies can have markedly different injury regimes, likely to lead to strong intraspecific variation in colony fitness and resilience

  • Geographically conserved rates of background mortality among common reef‐building corals in Lhaviyani Atoll, Maldives, versus northern Great Barrier Reef, Australia
    'Springer Science and Business Media LLC', 2015
    Co-Authors: Pisapia Chiara, Sweatman Hugh, Sweet Michael, Pratchett, Morgan Stuart
    Abstract:

    Even in the absence of major disturbances (e.g., cyclones and bleaching), corals are consistently subject to high levels of background mortality, which undermines individual fitness and resilience of coral colonies. Most studies of coral mortality however only focus on catastrophic mortality associated with major acute disturbance events, neglecting to consider background levels of chronic mortality that have a significant influence on population structure and turnover. If, for example, there are geographic differences in the prevalence of injuries and rates of background mortality, coral communities may vary in their susceptibility to acute large-scale disturbances and environmental change. This study quantified the preva- lence and severity of partial mortality for four dominant and widespread coral taxa (massive Porites, encrusting Montipora, Acropora Hyacinthus, and branching Pocillopora) at Lhaviyani Atoll, Maldives, and on the northern Great Barrier Reef, Australia. The prevalence and severity of sublethal injuries varied greatly among taxa, but was generally similar between locations; on the Great Barrier Reef, 99.4% Porites colonies, 66% of A. Hyacinthus, and 64% of Pocillopora had conspicuous injuries, compared to 92.4% of Porites, 47.5% of A. Hyacinthus, and 44% of Pocillopora colonies in Lhaviyani Atoll. These results suggest that background rates of mortality and injury, and associated resilience of coral populations and communities to large-scale disturbances, are conserved at large geographic scales, though adjacent colonies can have markedly different injury regimes, likely to lead to strong intraspecific variation in colony fitness and resilience

  • Spatial, temporal and taxonomic variation in the incidence of partial mortality among reef-building corals
    2015
    Co-Authors: Pisapia Chiara
    Abstract:

    Until now, most studies of coral reef degradation have focused on catastrophic mortality associated with acute disturbances (e.g., coral bleaching and outbreaks of crown-of-thorns starfish), but even in the absence of major disturbances corals are consistently subject to high levels of background mortality. In particular, corals are regular subject to high levels of partial mortality (or injuries) caused by chronic or persistent disturbances, which can have critical influence on population dynamics and resilience of coral populations. Spatial, temporal and taxonomic differences in injury regimes are important for understanding vulnerability and resilience of scleractinian corals to acute disturbances and environmental change. This thesis explicitly assesses variation in rates of background mortality, and mostly partial mortality, at both small (between adjacent colonies) and large (between locations in different ocean basins) scales. To establish baseline levels of partial mortality among common reef-building corals, I first quantified prevalence (proportion of colonies with injuries) and severity (areal extent of injuries on individual colonies) of injuries across four common coral taxa (massive Porites, encrusting Montipora, Acropora Hyacinthus and branching Pocillopora) on the Great Barrier Reef, Australia. A total of 2,276 adult colonies were surveyed annually over three years across three latitudinal sectors, nine reefs and 27 sites along the Great Barrier Reef. The prevalence of injuries was very high (>83%) for all coral taxa, but especially high for Porites (91%) and Montipora (85%). Within individual taxa, there was significant temporal or spatial variation in prevalence of partial mortality in Montipora and Pocillopora. Severity of partial mortality on injured colonies ranged from 5% for A. Hyacinthus up to 21% for Montipora, and varied both spatially and temporally. These findings confirm that background levels of partial mortality are high even in the absence of major disturbances, and are likely to significant influence differential vulnerability of colonies, populations and coral species to other more acute disturbances. Building on my initial studies on the Great Barrier Reef, I then compared rates of background mortality (including both partial and whole colony mortality) between Lhaviyani Atoll, Maldives and the northern Great Barrier Reef, Australia. Comparisons were made for four dominant and widespread coral taxa (Porites, Montipora, Acropora Hyacinthus and Pocillopora), which were surveyed across multiple reefs and sites at each location. Prevalence of partial mortality was consistently higher on the GBR (99.4% of colonies in Porites, 66% in Acropora Hyacinthus and 64% in Pocillopora) than at Lhaviyani Atoll (92.4% in Porites, 47.5% in A. Hyacinthus and 44% in Pocillopora). Conversely, severity of partial mortality was higher for A. Hyacinthus and Porites (9.6% and 12.2%, respectively) at Lhaviyani Atoll than on the GBR (7% in A. Hyacinthus and 9.6% in Porites). However, marked differences in severity of partial mortality were most apparent at the smallest spatial scale (e.g., among colonies located on the same transect within the same habitat). This suggests that corals in different geographical locations are consistently subject to high levels of background mortality, but the specific effects are highly patchy and likely contribute to significant intercolony variation in susceptibility of corals to major disturbances (e.g., bleaching). After investigating spatial variation in tissue loss, I tested the specific effects of injuries on colony condition. Intraspecific variation in physiological condition was measured, based on total lipid content and zooxanthellae density, in adult colonies of two common and widespread coral species (Acropora spathulata and Pocillopora damicornis). Importantly, these corals were subject to different levels of biological and physical disturbances and marked intraspecific variation in the physiological condition of A. spathulata was clearly linked to differences in local disturbance regimes. Conversely, P. damicornis exhibited very limited intraspecific variation in physiological condition, despite marked differences in the severity of partial mortality. This study shows that the physiological condition of individual coral colonies is influenced by differences in injury regimes, at least for some coral taxa. Moreover, these differences in physiological condition are likely to have important effects on the fate and fitness of individual colonies, and especially their vulnerability to subsequent disturbances. Overall, my PhD research shows that the prevalence of coral injuries is consistently high (>80% of colonies have visible injuries) across different coral taxa and among reef locations spanning 10 degrees of latitude and in different ocean basins. The severity of injuries meanwhile, varies greatly among individual colonies within the same habitat and site, which may have important ramifications for susceptibility to acute disturbances and environmental change. Much more research is needed to understand the major causes of routine injuries to reef building corals, but studies on the effects of acute disturbances on coral populations and/ or communities should not discount background levels of mortality, and the extent to which this might further increase susceptibility to, and prevent recovery from, acute disturbances