Life history and production of mayflies, stoneflies, and caddisflies (Ephemeroptera, Plecoptera, and Trichoptera) in a spring-fed stream in Prince Edward Island, Canada: evidence for population asynchrony in spring habitats?

Abstract

We examined the life history and production of the Ephemeroptera, Plecoptera, and Trichoptera (EPT) community along a 500-m stretch of a hydrologically stable cold springbrook in Prince Edward Island during 1997 and 1998. Six mayfly species (Ephemeroptera), 6 stonefly species (Plecoptera), and 11 caddisfly species (Trichoptera) were collected from benthic and emergence samples from five sites in Balsam Hollow Brook. Eleven species were abundant enough for life-history and production analysis: Baetis tricaudatus, Cinygmula subaequalis, Epeorus (Iron) fragilis, and Epeorus (Iron) pleuralis (Ephemeroptera), Paracapnia angulata, Sweltsa naica, Leuctra ferruginea, Amphinemura nigritta, and Nemoura trispinosa (Plecoptera), and Parapsyche apicalis and Rhyacophila brunnea (Trichoptera). Life-cycle timing of EPT taxa in Balsam Hollow Brook was generally similar to other literature reports, but several species showed extended emergence periods when compared with other studies, suggesting a reduction in synchronization of life-cycle timing, possibly as a result of the thermal patterns in the stream. Total EPT secondary production (June 1997 to May 1998) was 2.74–2.80 g·m –2 ·year –1 dry mass (size-frequency method). Mayflies were dominant, with a production rate of 2.2 g·m –2 ·year –1 dry mass, followed by caddisflies at 0.41 g·m –2 ·year –1 dry mass, and stoneflies at 0.19 g·m –2 ·year –1 dry mass. More than half of the species found in the study stream represented new distribution records for Prince Edward Island.