Drift distance of macroinvertebrates throughout summer in headwater tributaries of the Calapooia River

Abstract

Drifting invertebrates from small headwater streams are a food subsidy for fi shes and other downstream consumers in larger streams. This subsidy can become especially important for stream fi shes during summer due to high metabolic demand caused by elevated water temperatures. The source length in small streams contributing these drifting invertebrates to fi sh bearing habitat has not been established. We conducted an experiment to determine if summer drift delivered by headwater streams to larger channels is infl uenced by contributions originating more than 100 m upstream. We conducted this experiment on tributaries of the Calapooia River, Oregon, USA. We blocked drift with 250 µm mesh nets in three streams 100 m upstream of our sample nets continuously for 48 d. We also sampled fi ve streams without blocking nets. Four 24 h samples of drift were collected prior to the placement of blocking nets and every two weeks afterwards at each stream. Overall mean abundance and mean biomass of drift did not differ between blocked and unblocked streams for any sampling period. There was a temporal trend at all sites of declining invertebrate abundance and biomass. We found no treatment effect for any of the most common insect orders or for the 16 genera that comprised at least 1 % of the total organisms captured. The majority of invertebrate drift is of local origin in headwater streams during summer basefl ow.

Interactions of baseflow habitat constraints: Macroinvertebrate drift, stream temperature, and physical habitat for anadromous salmon in the Calapooia River, Oregon

“…In daytime‐only sampling, Urabe et al () found highly variable results with a range of 0.008–0.062 mg m −3 in mountainous Japanese streams. In even smaller streams, Wipfli and Gregovich () in south‐east Alaska, and Danehy et al () in Calapooia River tributaries, found drift concentration biomass in headwater streams in late summer of 1–4 mg m −3 and 0.2–1.1 mg m −3 , respectively. Overall observed drift concentrations are within the range of variability seen elsewhere.…”

“…Summer baseflow is a physical and energetic bottleneck for reasons beyond the obvious constraint of elevated stream temperatures. Drift distance of individual invertebrates is shorter at baseflow than higher flow (Danehy, Langshaw, Duke, & Bilby, ; Elliott, ; McLay, ; Sagar & Glova, ), potentially lowering drift concentration. Lower flows reduce suitable feeding locations for individual fish (Fausch, ; Hayes, Hughes, & Kelly, ), which affects population growth (Mellina & Hinch, ; Rosenfeld, ).…”

Effects of Climate‐Related Stream Factors on Patterns of Individual Summer Growth of Cutthroat Trout

“…Furthermore, drifting invertebrates travel shorter distances during periods of low discharge, which can further reduce prey availability at foraging locations (Danehy et al. ). Significant decreases in rates of prey delivery depress growth rates of closely related Rainbow Trout O. mykiss under the direct manipulation of discharges (Harvey et al.…”

Stream inflow and predation risk affect littoral habitat selection by benthic fish

“…Similarly, taxonomic composition of the macroinvertebrate benthos at stream inflows was not measurably changed by the drift of stream taxa. Drift distances can be short (Danehy et al. , 2011) and proportional to stream size (Kiffney et al.…”

“…Similarly, taxonomic composition of the macroinvertebrate benthos at stream inflows was not measurably changed by the drift of stream taxa. Drift distances can be short (Danehy et al, 2011) and proportional to stream size (Kiffney et al, 2006); thus, the minimal impact observed on littoral macroinvertebrate biomass and composition might be due to the small size of the streams. Alternatively, if stream taxa were consumed selectively by C. asper, the composition of the macroinvertebrate benthos might be similar in both inflow and control plots.…”