Main Title |
Randomized Intervention Analysis and the Interpretation of Whole-Ecosystem Experiments. |
Author |
Carpenter, S. R. ;
Frost, T. M. ;
Heisey, D. ;
Kratz, T. K. ;
|
CORP Author |
Wisconsin Univ.-Madison. Center for Limnology.;Environmental Research Lab.-Duluth, MN.;National Science Foundation, Washington, DC. |
Publisher |
c1989 |
Year Published |
1989 |
Report Number |
NSF-DEB80-12313 ;NSF-BSR83-08918; EPA/600/J-89/506; |
Stock Number |
PB91-163535 |
Additional Subjects |
Ecosystems ;
Stochastic processes ;
Lakes ;
Random processes ;
Time series analysis ;
Monte Carlo method ;
Experimental design ;
Biological effects ;
Statistical analysis ;
Limnology ;
Water pollution ;
pH ;
Acidification ;
Little Rock Lake ;
Reprints ;
|
Holdings |
Library |
Call Number |
Additional Info |
Location |
Last Modified |
Checkout Status |
NTIS |
PB91-163535 |
Some EPA libraries have a fiche copy filed under the call number shown. |
|
07/26/2022 |
|
Collation |
13p |
Abstract |
Randomized intervention analysis (RIA) is used to detect changes in a manipulated ecosystem relative to an undisturbed reference system. It requires paired time series of data from both ecosystems before and after manipulation. RIA is not affected by non-normal errors in data. Monte Carlo simulation indicated that, even when serial autocorrelation was substantial, the true P value (i.e., from nonautocorrelated data) was <.05 when the P value from autocorrelated data was <.01. The authors applied RIA to data from 12 lakes (3 manipulated and 9 reference ecosystems) over 3 yr. RIA consistently indicated changes after major manipulations and only rarely indicated changes in ecosystems that were not manipulated. Less than 3% of the data sets they analyzed had equivocal results because of serial autocorrelation. RIA appears to be a reliable method for determining whether a nonrandom change has occurred in a manipulated ecosystem. Ecological arguments must be combined with statistical evidence to determine whether the changes demonstrated by RIA can be attributed to a specific ecosystem manipulation. (Copyright (c) 1989 by the Ecological Society of America.) |