Effectiveness of Sampling Strategies for Intertidal Monitoring

Hawkins, Stephen J.; Hartnoll, Richard G.; Williams, Gary A.; Azzopardi, Paul; Burrows, MT; Ellard, F. M.

doi:10.2166/wst.1986.0181

Cited by 4 publications

(2 citation statements)

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“…However, larger areas are required before quantitative estimates can be made. These sample sizes are relatively high compared with those needed in macrobenthic communities (Hawkins et al, 1986) indicating that species distribution is more variable. This variability represents a high degree of natural spatial heterogeneity within microbial communities found both at different study sites and different times of the year.…”

Section: Discussionmentioning

confidence: 99%

An investigation of methods for sampling microbial films on rocky shores

Hill

Hawkins

1990

J. Mar. Biol. Ass.

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Chlorophyll analysis and methods of direct observation of rock surfaces under the SEM were used to estimate composition and abundance of epilithic microbial taxa. Effectiveness of different chlorophyll extraction techniques was assessed. Extraction from ground and intact rock was compared using both hot methanol and acetone extraction methods. Hot methanol extraction from intact rock provided the most accurate and precise estimates of chlorophyll content. SEM preparation methods were compared. Microbial taxa were counted under the SEM from cryostage, critically point dried and air-dried material. It was concluded that air drying was the most appropriate preparation method for SEM observation. Air drying provides reasonable estimates of microbial composition and abundance and was less time consuming so allowing an adequate number of samples to be analysed. Cumulative species number with sampling effort curves were used to establish minimal sample sizes with respect to estimates of species number. Sequential estimates of mean abundance with increasing sample size were used to determine the effects of increasing sample size on estimates of abundance of the dominant taxa. These estimates were compared at different times of the year and for two different locations. Microbial communities were found to be extremely patchy in distribution. However, sample sizes required to give good estimates of taxa number and abundance were established. These estimates were found to be similar for the main taxa at different times of the year and at different locations.

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Section: Discussionmentioning

confidence: 99%

An investigation of methods for sampling microbial films on rocky shores

Hill

Hawkins

1990

J. Mar. Biol. Ass.

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“…In these cases, species richness is often less sensitive -values can remain constant despite a change in the type of species present (Somerfield et al 1997). Fluctuations in species richness can be confounded by natural environmental variation , Blanchard & Bourget 1999, meaning they do not necessarily denote a decline in ecosystem 'health' or functional diversity (Hawkins et al 1986, Keough & Quinn 1991, Clarke 1993, Dufrene & Legendre 1997. Another disadvantage of a number of diversity indices is that they are often affected by sampling effort (Warwick & Clarke 1995, 1998, Rogers et al 1999, Magurran 2004.…”

Section: Introductionmentioning

confidence: 99%

Measures of taxonomic distinctness do not reliably assess anthropogenic impacts on intertidal mollusc communities

Costa¹,

O'Hara²,

Keough³

2010

Mar. Ecol. Prog. Ser.

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Indices of taxonomic distinctness measure the taxonomic breadth of a community and may be more sensitive to human impacts than conventional diversity indices. They have the advantage of being, in theory, insensitive to sampling effort and can be calculated using presence/absence data. The average taxonomic distinctness index and variation in taxonomic distinctness index were used to assess the effects of putative human impacts on molluscan community composition at 63 rocky intertidal platforms on the coast of Victoria, Australia. The use of 2 sampling techniques, viz. timed searches and quadrats, was compared. Sites exposed to sewage discharge maintained high taxonomic distinctness, and those exposed to high levels of human visitation did not have consistently lower values than controls. Results varied, sometimes markedly, depending on which survey technique was used. Neither average taxonomic distinctness nor its variance were strongly correlated with large-scale environmental gradients, small-scale habitat differences or other diversity indices. It is most likely that taxonomic distinctness measures did not discriminate sites exposed to putative disturbance because of the high taxonomic diversity of intertidal mollusc assemblages, and because low values of taxonomic distinctness were not exclusive of impacted conditions.

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Ecological Monitoring — The Need for a Standard

Pagett¹

1989

Watershed 89

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Effectiveness of Sampling Strategies for Intertidal Monitoring

Cited by 4 publications

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An investigation of methods for sampling microbial films on rocky shores

An investigation of methods for sampling microbial films on rocky shores

Measures of taxonomic distinctness do not reliably assess anthropogenic impacts on intertidal mollusc communities

Ecological Monitoring — The Need for a Standard

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