TY - JOUR
T1 - Vertical and seasonal distribution of hyporheic invertebrates in streams with different glacial histories
AU - Varricchione, Jeffrey T.
AU - Thomas, Steven A.
AU - Minshall, G. Wayne
N1 - Funding Information:
A number of people assisted in various aspects of this study. Field assistance was provided by Cary Myler, Eric Snyder, Mark Overfield, Kelly Sant, Kate Bowman, Jesse Schomberg, Joe Serotnak, Scott Relyea, Christina Relyea, Jason Nelson, Kari Myler, Michael Monaghan, and Jamie Larson. Many folks provided constructive comments during the development of this paper, including Christopher T. Robinson, Robert Anderson, Lee Matthews, Todd Royer, and three anonymous reviewers. We thank all the folks who have been involved with this project. Partial funding was provided by Bioanalysts, Inc. (Boise, Idaho, USA) and by grant no. S96-12 from the Graduate Student Research and Scholarship Committee of Idaho State University (Pocatello, Idaho, USA).
PY - 2005/12
Y1 - 2005/12
N2 - We investigated the vertical, lateral, and seasonal distribution of hyporheic invertebrates at five stream sites in Idaho (unglaciated areas) and seven sites in Montana (glaciated areas), U.S.A. Conservative tracer releases and transient storage zone analyses were conducted to help characterize study sites. Hyporheic invertebrates and substrate were sampled by freeze-coring with electro-shocking, and mini-piezometers were used to measure other hyporheic conditions, including vertical hydraulic gradient (VHG). Wells were installed at some Montana sites (range: 5-175 m lateral to the channel) and shallow pits were excavated at some Idaho sites (5 m lateral to the channel) to sample hyporheic invertebrates in these saturated sediments regions. Environmental conditions varied widely among sites and between surface and hyporheic zones at each site, and most hyporheic habitat measures differed significantly between glaciated and unglaciated streams. In-channel invertebrate density and taxa richness generally decreased with increasing depth into the streambed, regardless of geographic location, history of glaciation, or season. Although hyporheic invertebrate mean density and (to a lesser extent) richness values at individual depth layers (e.g., 10-20 cm, 20-30 cm) mostly were greater in the glaciated region than the unglaciated region, density and richness between 10-50 cm did not differ significantly between the two regions. Hydrologic variables (VHG; As/A [ratio of transient-storage-zone- to channel- cross-sectional areas]; TTs [turnover time of storage]; and R h [hydraulic retention factor]) provided the best explanation for differences in sub-channel invertebrate density and richness patterns. The observation that benthic invertebrates occurred in freeze-core, well, and open-pit samples contributes to existing evidence that aquatic invertebrates occupy habitats that extend considerable distances from the active channel.
AB - We investigated the vertical, lateral, and seasonal distribution of hyporheic invertebrates at five stream sites in Idaho (unglaciated areas) and seven sites in Montana (glaciated areas), U.S.A. Conservative tracer releases and transient storage zone analyses were conducted to help characterize study sites. Hyporheic invertebrates and substrate were sampled by freeze-coring with electro-shocking, and mini-piezometers were used to measure other hyporheic conditions, including vertical hydraulic gradient (VHG). Wells were installed at some Montana sites (range: 5-175 m lateral to the channel) and shallow pits were excavated at some Idaho sites (5 m lateral to the channel) to sample hyporheic invertebrates in these saturated sediments regions. Environmental conditions varied widely among sites and between surface and hyporheic zones at each site, and most hyporheic habitat measures differed significantly between glaciated and unglaciated streams. In-channel invertebrate density and taxa richness generally decreased with increasing depth into the streambed, regardless of geographic location, history of glaciation, or season. Although hyporheic invertebrate mean density and (to a lesser extent) richness values at individual depth layers (e.g., 10-20 cm, 20-30 cm) mostly were greater in the glaciated region than the unglaciated region, density and richness between 10-50 cm did not differ significantly between the two regions. Hydrologic variables (VHG; As/A [ratio of transient-storage-zone- to channel- cross-sectional areas]; TTs [turnover time of storage]; and R h [hydraulic retention factor]) provided the best explanation for differences in sub-channel invertebrate density and richness patterns. The observation that benthic invertebrates occurred in freeze-core, well, and open-pit samples contributes to existing evidence that aquatic invertebrates occupy habitats that extend considerable distances from the active channel.
KW - Glaciated
KW - Hyporheos
KW - Transient storage zone
KW - Unglaciated
KW - Vertical hydrologic exchange
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U2 - 10.1007/s00027-005-0784-3
DO - 10.1007/s00027-005-0784-3
M3 - Article
AN - SCOPUS:28844451045
SN - 1015-1621
VL - 67
SP - 434
EP - 453
JO - Aquatic Sciences
JF - Aquatic Sciences
IS - 4
ER -