Aquatic invertebrate sampling at selected outfalls in Operable Unit 1082; Technical areas 9, 11, 16 and 22

In field biology, interactions between wildlife and in situ equipment occur often. These interactions have the potential to induce a variety of behaviours in local fauna. Here, we note the destructive behaviour exhibited by the Muskrat (Ondatra zibethicus) following deployment of aquatic invertebrate traps for research purposes at 12 wetlands located in central Saskatchewan. Of 24 aquatic insect emergence traps used on seven wetlands in our study, 14 (58%) required recurring repairs. In addition, on several occasions, leaf litter bags and their anchoring stakes were torn or chewed. The recurring damage took place in wetlands with Muskrat lodges. We recommend structural modifications to aquatic invertebrate traps in wetland complexes densely inhabited by Muskrats and other semi-aquatic rodents.

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Debris dams as habitat for aquatic invertebrates in forested headwater streams: a large-scale field experiment

Marine and Freshwater Research ◽

10.1071/mf18216 ◽

2019 ◽

Vol 70 (5) ◽

pp. 734

Author(s):

Brenda R. Baillie ◽

Brendan J. Hicks ◽

Ian D. Hogg ◽

Michael R. van den Heuvel ◽

Mark O. Kimberley

Keyword(s):

Large Scale ◽

Aquatic Invertebrates ◽

Headwater Streams ◽

Dam Removal ◽

Aquatic Invertebrate ◽

Invertebrate Communities ◽

Debris Dams ◽

Scale Field ◽

Large Scale Field ◽

Debris Dam

To evaluate the effects of debris dams on aquatic invertebrate communities, we sampled benthic invertebrates in debris dams and riffles in three forested headwater streams in New Zealand. As part of a large-scale field experiment, debris dams were subsequently removed from three treatment sections in each of the streams to assess effects on invertebrate communities. Prior to debris dam removal, total invertebrate densities in debris dams were not significantly different from those in riffles. However, densities of Ephemeroptera, Plecoptera and Trichoptera taxa were significantly higher in debris dams than in riffles. Debris dams contained a higher number of less common taxa (defined as <1% of total catch) and significantly higher densities of shredders. Densities for Coleoptera, Diptera and Trichoptera taxa were significantly higher in the autumn than in the spring. Non-metric multidimensional scaling axis scores indicated that both habitat and season had a significant effect on aquatic invertebrate community composition. At the reach scale, the effects of debris dam removal on the aquatic invertebrate communities were not statistically detectable because debris dams comprised only a small proportion of total habitat. However, these data highlight the importance of debris dams in contributing to the diversity of aquatic invertebrates in forested headwater streams.

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