[Taxacom] chance and ecological evolution

John Grehan jgrehan at sciencebuff.org
Tue Nov 8 11:06:40 CST 2011

Although some on this list regard panbiogeographic approaches and
interpretations to be something outside 'normal' scientific discourse,
others may be interested in the article below (in J Biog) where
ecologists have been able to incorporate panbiogeographic perspectives
and draw conclusions with respect to ecological approaches to community
structure. I found it particularly interesting that for these ecologists
'chance' does not exist.


John Grehan


The control of community composition

by distance, environment and history:

a regional-scale study of the mountain

grasslands of southern New Zealand

J. Bastow Wilson1* and Colin D. Meurk2



The major puzzle here is the large unpredictable element in site

floras. Although there are as yet too few comparable studies to

draw conclusions (Table 6), the indications are that strong

predictability of community composition from distance and the

environment will be possible only when there is considerable

heterogeneity and when examining only one guild of the flora.

That said, the relationships with lower plants were not strong

here. The slightly or considerably lower predictability of

abundance indicates that the primary control is on the presence

of species, whereas their abundance may be more dependent on

disturbance history. The environmental correlations are those

that would be expected, save for the importance of soil

chemistry for lower plants. We would expect any unmeasured

environmental factors or historical disturbance to be spatially

autocorrelated and thus to be seen in the distance residuum,

but often this is small. The same argument applies to some

extent to an explanation in terms of terrane history (cf. Heads,

2010), although the methods used here are not those of

panbiogeography. The invocation of chance is long established

in ecology (e.g. Palmgren, 1926) and has been emphasized

in recent years (e.g. Karst et al., 2005), but it is often invoked

when other explanations have failed, and is impossible to

falsify. In the final analysis, chance does not exist (Wilson,

2002), and we must admit that the control of species composition

is often by historical and other factors beyond our



Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723


Ghost moth research

Human evolution and the great apes


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