Morrison, David A. and Le Brocque, Andrew F. and Clarke, Peter J. (1995) An assessment of some improved techniques for estimating the abundance (frequency) of sedentary organisms. Vegetatio, 120 (2). pp. 131-145. ISSN 0042-3106
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Official URL: http://dx.doi.org/10.1007/BF00034343
Identification Number or DOI: doi: 10.1007/BF00034343
The traditional sampling method for estimating frequency (the number of sub-quadrats containing a basal part of the organisms) is compared, using both computer simulations and direct comparison in the field, to two new methods that use a compound series of variable-sized concentric sub-quadrats. Both the new frequency-score and the new importance-score methods are closer approximations of density than is the standard frequency method, and the estimates produced by both of the new methods are less affected by the choice of sub-quadrat size and the spatial distribution (dispersion) of the organisms (i.e. clumping and regularity). Thus, the two nested-quadrat methods appear to ameliorate the usual frequency limitations associated with sub-quadrat size and organism dispersion, by the use of a range of different sub-quadrat sizes. This is important in community studies, where the component species may show a wide range of densities and dispersions. Both of the new methods are easily employed in the field. The importance-score method involves no more sampling effort than does standard qualitative (presenceabsence)sampling, and it can therefore be used to sample a larger quadrat area than would normally be used for frequency sampling. This makes the method much more cost-effective as a means of estimating abundance, and it allows a greater number of the rarer species to be included in the sampling. The frequency-score method is more time-consuming, but it is capable of detecting more subtle community patterns. This means that it is particularly useful for the study of species-poor communities or where small variations in composition need to be detected.
|Item Type:||Article (Commonwealth Reporting Category C)|
|Additional Information:||Author version not held.|
|Uncontrolled Keywords:||abundance; frequency; frequency-score; importance-score; presence-absence; sampling|
|Fields of Research (FOR2008):||06 Biological Sciences > 0602 Ecology > 060208 Terrestrial Ecology|
06 Biological Sciences > 0602 Ecology > 060202 Community Ecology(excl. Invasive Species Ecology)
|Socio-Economic Objective (SEO2008):||D Environment > 96 Environment > 9608 Flora, Fauna and Biodiversity > 960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified|
D Environment > 96 Environment > 9605 Ecosystem Assessment and Management > 960599 Ecosystem Assessment and Management not elsewhere classified
|Deposited On:||09 Apr 2010 22:20|
|Last Modified:||20 Jun 2012 12:21|
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