Multiple-site and -year analyses of stream insect emergence: a test or ecological theory
1993
Statzner, B. (Lyon Univ., Villeurbanne (France). URA CNRS 1451 Ecologie des Eaux Douces et les Grands Fleuves) | Resh, V.H.
The use of existing data sets o test applicability of existing ecological theory is an uncommon but potentially cost-effective approach for exploitation of previously accumulated knowledge. Studies on the emergence of insects from small streams have been a major research topic in aquatic ecology, particularly in Austria and Germany; the availability of emergence data from these two countries, covering over 1 million identified specimens, from 18 sites, and for 32 collection years is an example of such exploitable information. Concurrent, estimates of annual emergence biomass and annual benthic secondary production for 18 aquatic insect populations showed a statistically significant relationship, contradicting the premise that emergence data do not provide any quantitative measure for a given stream area. Therefore, the emergence data were examined to test various predictions from ecological theory. Observed richness of emerging species to three orders of lotic insects - the Ephemeroptera, Plecoptera, and Trichoptera (EPT - over 15 years at one site did not agree with predictions based on either flow predictability or change in flow and the "habitat templet concept". Trends in observed richness of emerging EPT species over 1 year at 18 sites agreed weakly with predictions using either pH values or the annual temperature amplitude and the "intermediate disturbance hypothesis", or using either annual temperature amplitude or total biomass of EPT emergence and the "disturbance-productivity-diversity model".
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