Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach

DS Schoeman, A McLachlan, JE Dugan

    Research output: Contribution to journalArticle

    33 Citations (Scopus)

    Abstract

    Exposed sandy beaches are important, sensitive and widespread coastal habitats. Although they have been studied for more than 50 years, investigators have been reluctant to attempt manipulative experiments due to the dynamic nature of these environments. Consequently, the ecology of exposed sandy beaches remains relatively poorly understood. We conducted a community-level, manipulative experiment involving a simulated anthropogenic disturbance on an exposed microtidal sandy beach in the Eastern Cape, South Africa; the first of its kind and scale. This study comprised pre- and post-impact sampling at an experimental site and two control sites. The impact involved excavating and removing a 200 m(2) quadrat of sand from the mid-intertidal of the experimental site to a depth of 0.3 m. The intention was to address the prediction that anthropogenic disturbances would be detectable if appropriate spatial and temporal scales were investigated. The following variables were monitored: transect gradient; species richness; macrofaunal abundance; and both the abundance and biomass of the dominant infaunal species, the beach clam Donax serra Roding. Analyses revealed significant differences in temporal patterns of all response variables amongst sites. Some evidence linked these changes to the experimental disturbance, although impacts appear temporary, being ameliorated within, at most, one semi-lunar cycle. This confirms that it is possible to successfully conduct manipulative experiments on exposed sandy beaches. However, the uncontrollable, natural dynamics of the beach face, as expressed by intertidal gradient, contributed significantly to the description of spatio-temporal variation in biotic response variables. It is concluded that to isolate treatment effects from those of natural variation, two advances are necessary on the current research approach. First, experimental designs must take cognizance of the fact that exposed, microtidal sandy beaches have little in common with other intertidal habitats; and second, large-scale treatments must be replicated in space. (C) 2000 Academic Press.
    LanguageEnglish
    Pages869-884
    JournalESTUARINE COASTAL AND SHELF SCIENCE
    Volume50
    Issue number6
    Publication statusPublished - Jun 2000

    Fingerprint

    intertidal environment
    beach
    disturbance
    experiment
    lunar cycle
    habitat
    experimental design
    temporal variation
    transect
    species richness
    ecology
    sand
    biomass
    sampling
    prediction

    Cite this

    Schoeman, DS., McLachlan, A., & Dugan, JE. (2000). Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach. 50(6), 869-884.
    Schoeman, DS ; McLachlan, A ; Dugan, JE. / Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach. 2000 ; Vol. 50, No. 6. pp. 869-884.
    @article{43c951c524ba4637b9c83aa930b5b51a,
    title = "Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach",
    abstract = "Exposed sandy beaches are important, sensitive and widespread coastal habitats. Although they have been studied for more than 50 years, investigators have been reluctant to attempt manipulative experiments due to the dynamic nature of these environments. Consequently, the ecology of exposed sandy beaches remains relatively poorly understood. We conducted a community-level, manipulative experiment involving a simulated anthropogenic disturbance on an exposed microtidal sandy beach in the Eastern Cape, South Africa; the first of its kind and scale. This study comprised pre- and post-impact sampling at an experimental site and two control sites. The impact involved excavating and removing a 200 m(2) quadrat of sand from the mid-intertidal of the experimental site to a depth of 0.3 m. The intention was to address the prediction that anthropogenic disturbances would be detectable if appropriate spatial and temporal scales were investigated. The following variables were monitored: transect gradient; species richness; macrofaunal abundance; and both the abundance and biomass of the dominant infaunal species, the beach clam Donax serra Roding. Analyses revealed significant differences in temporal patterns of all response variables amongst sites. Some evidence linked these changes to the experimental disturbance, although impacts appear temporary, being ameliorated within, at most, one semi-lunar cycle. This confirms that it is possible to successfully conduct manipulative experiments on exposed sandy beaches. However, the uncontrollable, natural dynamics of the beach face, as expressed by intertidal gradient, contributed significantly to the description of spatio-temporal variation in biotic response variables. It is concluded that to isolate treatment effects from those of natural variation, two advances are necessary on the current research approach. First, experimental designs must take cognizance of the fact that exposed, microtidal sandy beaches have little in common with other intertidal habitats; and second, large-scale treatments must be replicated in space. (C) 2000 Academic Press.",
    author = "DS Schoeman and A McLachlan and JE Dugan",
    year = "2000",
    month = "6",
    language = "English",
    volume = "50",
    pages = "869--884",
    number = "6",

    }

    Schoeman, DS, McLachlan, A & Dugan, JE 2000, 'Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach', vol. 50, no. 6, pp. 869-884.

    Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach. / Schoeman, DS; McLachlan, A; Dugan, JE.

    Vol. 50, No. 6, 06.2000, p. 869-884.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach

    AU - Schoeman, DS

    AU - McLachlan, A

    AU - Dugan, JE

    PY - 2000/6

    Y1 - 2000/6

    N2 - Exposed sandy beaches are important, sensitive and widespread coastal habitats. Although they have been studied for more than 50 years, investigators have been reluctant to attempt manipulative experiments due to the dynamic nature of these environments. Consequently, the ecology of exposed sandy beaches remains relatively poorly understood. We conducted a community-level, manipulative experiment involving a simulated anthropogenic disturbance on an exposed microtidal sandy beach in the Eastern Cape, South Africa; the first of its kind and scale. This study comprised pre- and post-impact sampling at an experimental site and two control sites. The impact involved excavating and removing a 200 m(2) quadrat of sand from the mid-intertidal of the experimental site to a depth of 0.3 m. The intention was to address the prediction that anthropogenic disturbances would be detectable if appropriate spatial and temporal scales were investigated. The following variables were monitored: transect gradient; species richness; macrofaunal abundance; and both the abundance and biomass of the dominant infaunal species, the beach clam Donax serra Roding. Analyses revealed significant differences in temporal patterns of all response variables amongst sites. Some evidence linked these changes to the experimental disturbance, although impacts appear temporary, being ameliorated within, at most, one semi-lunar cycle. This confirms that it is possible to successfully conduct manipulative experiments on exposed sandy beaches. However, the uncontrollable, natural dynamics of the beach face, as expressed by intertidal gradient, contributed significantly to the description of spatio-temporal variation in biotic response variables. It is concluded that to isolate treatment effects from those of natural variation, two advances are necessary on the current research approach. First, experimental designs must take cognizance of the fact that exposed, microtidal sandy beaches have little in common with other intertidal habitats; and second, large-scale treatments must be replicated in space. (C) 2000 Academic Press.

    AB - Exposed sandy beaches are important, sensitive and widespread coastal habitats. Although they have been studied for more than 50 years, investigators have been reluctant to attempt manipulative experiments due to the dynamic nature of these environments. Consequently, the ecology of exposed sandy beaches remains relatively poorly understood. We conducted a community-level, manipulative experiment involving a simulated anthropogenic disturbance on an exposed microtidal sandy beach in the Eastern Cape, South Africa; the first of its kind and scale. This study comprised pre- and post-impact sampling at an experimental site and two control sites. The impact involved excavating and removing a 200 m(2) quadrat of sand from the mid-intertidal of the experimental site to a depth of 0.3 m. The intention was to address the prediction that anthropogenic disturbances would be detectable if appropriate spatial and temporal scales were investigated. The following variables were monitored: transect gradient; species richness; macrofaunal abundance; and both the abundance and biomass of the dominant infaunal species, the beach clam Donax serra Roding. Analyses revealed significant differences in temporal patterns of all response variables amongst sites. Some evidence linked these changes to the experimental disturbance, although impacts appear temporary, being ameliorated within, at most, one semi-lunar cycle. This confirms that it is possible to successfully conduct manipulative experiments on exposed sandy beaches. However, the uncontrollable, natural dynamics of the beach face, as expressed by intertidal gradient, contributed significantly to the description of spatio-temporal variation in biotic response variables. It is concluded that to isolate treatment effects from those of natural variation, two advances are necessary on the current research approach. First, experimental designs must take cognizance of the fact that exposed, microtidal sandy beaches have little in common with other intertidal habitats; and second, large-scale treatments must be replicated in space. (C) 2000 Academic Press.

    M3 - Article

    VL - 50

    SP - 869

    EP - 884

    IS - 6

    ER -

    Schoeman DS, McLachlan A, Dugan JE. Lessons from a disturbance experiment in the intertidal zone of an exposed sandy beach. 2000 Jun;50(6):869-884.