Effects of Predatory Sculpin on the Chironomid Communities in an Arctic Lake

• Published in: Ecology
• Main Author: Hershey, Anne E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1985
• Subjects: Arctic; Arctic Lake
• Online Access: http://dx.doi.org/10.2307/1939165; http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F1939165; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2307%2F1939165; https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.2307/1939165

To determine the importance of fish predation and habitat heterogeneity in structuring the chironomid community of an arctic lake, I used a combination of field and laboratory experiments in conjunction with field sampling data. Chironomid density was consistently °1.5 times as high in macrophyte—covered as in bare sediments in the soft—sediment littoral zone of arctic Toolik Lake. In laboratory experiments, most chironomid taxa showed no preference for one habitat over the other, but schulpins, the major predators on larval chironomids, were more efficient foragers in bare sediments than in macrophytes. Field exclosure experiments in macrophyte and bare—sediments habitats indicated that macrophytes afforded chironomids a refuge from their sculpin predators. At the end of a 21—d experiment, chironomid density in unenclosed areas significantly lower than in fish exclosures in bare sediments, but this was not so in macrophytes. This difference was due to an effect of sculpin on chironomids that are small rather than on large chironomids or on any single chironomid taxon or broad trophic group (predaceous vs. nonpredaceous). Small chironomids were probably more available as prey because of their tube—dwelling and sediment—penetrating behaviors.