Iwao's patchiness recession through the origin: biological importance and efficiency of sampling applications

Waters, Edward Kyle, Furlong, Michael J., Benke, Kurt K., Grove, James Robin and Hamilton, Andrew John (2014) Iwao's patchiness recession through the origin: biological importance and efficiency of sampling applications. Population Ecology, 56 2: 393-399. doi:10.1007/s10144-013-0417-y

Author Waters, Edward Kyle
Furlong, Michael J.
Benke, Kurt K.
Grove, James Robin
Hamilton, Andrew John
Title Iwao's patchiness recession through the origin: biological importance and efficiency of sampling applications
Journal name Population Ecology   Check publisher's open access policy
ISSN 1438-3896
Publication date 2014-04
Year available 2013
Sub-type Article (original research)
DOI 10.1007/s10144-013-0417-y
Open Access Status
Volume 56
Issue 2
Start page 393
End page 399
Total pages 7
Place of publication Tokyo, Japan
Publisher Springer
Collection year 2014
Language eng
Abstract Iwao’s mean crowding-mean density relation can be treated both as a linear function describing the biological characteristics of a species at a population level, or a regression model fitted to empirical data (Iwao’s patchiness regression). In this latter form its parameters are commonly used to construct sampling plans for insect pests, which are characteristically patchily distributed or overdispersed. It is shown in this paper that modifying both the linear function and statistical model to force the intercept or lower functional limit through the origin results in more intuitive biological interpretation of parameters and better sampling economy. Firstly, forcing the function through the origin has the effect of ensuring that zero crowding occurs when zero individuals occupy a patch. Secondly, it ensures that negative values of the intercept, which do not yield an intuitive biological interpretation, will not arise. It is shown analytically that sequential sampling plans based on regression through the origin should be more efficient compared to plans based on conventional regression. For two overdispersed data sets, through-origin based plans collected a significantly lower sample size during validation than plans based on conventional regression, but the improvement in sampling efficiency was not large enough to be of practical benefit. No difference in sample size was observed when through-origin and conventional regression based plans were validated using underdispersed data. A field researcher wishing to adopt a through-origin form of Iwao’s regression for the biological reasons outlined above can therefore be confident that their sampling strategies will not be affected by doing so.
Keyword Mathematical biology
Mean crowding
Sequential sampling
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online ahead of print 30 October 2013.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Biological Sciences Publications
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Created: Fri, 28 Mar 2014, 15:39:06 EST by Michael Furlong on behalf of School of Biological Sciences