Effects of the nuisance diatom <i>Didymosphenia geminata</i> on invertebrates in a Rocky Mountain stream

Abstract

Nuisance blooms of the stalked diatom Didymosphenia geminata have become an increasing concern worldwide, yet little is known about their effect on stream food webs. We investigated the effects of D. geminata blooms on stream invertebrates of the East River in the western Rocky Mountains. Areas with natural blooming levels of D. geminata had greater total invertebrate density but similar invertebrate biomass when compared to areas of stream bottom where D. geminata was experimentally removed. Most notable was a dramatic increase in the density and biomass of Chironomidae larvae, which were 6.5 and 4.2 times greater, respectively, in areas with D. geminata blooms relative to areas where it was removed. The density and biomass of Perlidae stoneflies, historically rare in the East River, were 1.9 and 3.1 times greater, respectively, in areas containing D. geminata blooms. In contrast, Heptageniidae mayfly biomass decreased by 50% in areas with D. geminata blooms, but their density was unchanged. There was no significant change in either density or biomass of the numerically abundant and highly mobile mayfly, Baetidae. D. geminata did not significantly alter the growth rate of Baetis or Epeorus mayflies in experimental growth chambers. The thick mats of stalks created by D. geminata blooms likely alter stream food webs, particularly due to dramatic increases in the density of Chironomidae larvae.

Local Knowledge Graph (12 entities)

Related Works

Items connected by shared entities, co-authorship, citations, or semantic similarity.

References (25)

4 in Knowledge Hub, 21 external