Summary: TREE vol. 14, no. 9 September 1999 0169-5347/99/$ ­ see front matter © 1999 Elsevier Science Ltd. All rights reserved. PII: S0169-5347(99)01664-X 361
Historically, ecologists have empha-
sized the importance of average envi-
ronmental conditions. The concept of en-
vironmental variance is almost completely
absent from the 40 foundation papers
(published from 1887­1971) identified by
Real and Brown1. Through the 1960s, the
word `variance' appeared in the abstract
of only about ten papers per thousand
published by the Ecological Society of
America (Fig. 1). However, the number of
such papers has increased since then to
about 50 per thousand during the 1990s.
Thissuggestsagrowingrecognitionamong
ecologists that an explicit consideration
of variance is essential to explain many of
the important patterns and processes in
nature. Jensen's inequality provides a fun-
damental tool for understanding and pre-

Source: Ayres, Matthew.P. - Department of Biological Sciences, Dartmouth College

Collections: Environmental Sciences and Ecology