TY - GEN
T1 - The effect of natural hydrological disturbances (defined from hspf simulated hydrographs) on trout populations in ungaged streams of the great smoky mountain national park
AU - Neff, Keil J.
AU - Parker, Joseph
AU - Schwartz, John
AU - Kulp, Matt
AU - Moore, Steve
AU - Cai, Meijun
PY - 2009
Y1 - 2009
N2 - Hydrological processes impact the functioning of ecosystems and influence fish population dynamics. In the Great Smoky Mountains National Park (GRSM), native brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss) populations have declined in some watersheds over the past two decades. Since 1986, 69 streams (369 sites) are routinely sampled by GRSM fisheries biologists, in which detailed data have been collected on fish condition (length, weight), abundance, year class strength, and biomass. To evaluate the impact of floods and droughts on trout, indicators of hydrologic alteration (IHA) were computed for 127 fish sampling sites between 1990 and 2007. The Hydrological Simulation Program - FORTRAN was used to model flows at each ungaged fish-sampling stream site. Outlets were defined for each site, and flow was calculated for the period of record. The model was calibrated by adjusting parameters including storage, infiltration, runoff, and ground water for three elevation classes (low<800m≤medium<1200m≤high) to fit flow output from model with two USGS gaging stations and one NPS gaging station. The ecohydrologic regimes, characterized using the IHA method, were compared with trout abundance and biomass at each site. Results indicated the abundance of young-of-the-year brook and rainbow trout significantly declined after extreme floods and droughts. In particular, low-flows during droughts significantly reduced recruitment for both brook and rainbow trout, which is likely due to decreased spawning habitat. Brook trout populations in larger low-elevation streams showed more stability compared to smaller headwater streams.
AB - Hydrological processes impact the functioning of ecosystems and influence fish population dynamics. In the Great Smoky Mountains National Park (GRSM), native brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss) populations have declined in some watersheds over the past two decades. Since 1986, 69 streams (369 sites) are routinely sampled by GRSM fisheries biologists, in which detailed data have been collected on fish condition (length, weight), abundance, year class strength, and biomass. To evaluate the impact of floods and droughts on trout, indicators of hydrologic alteration (IHA) were computed for 127 fish sampling sites between 1990 and 2007. The Hydrological Simulation Program - FORTRAN was used to model flows at each ungaged fish-sampling stream site. Outlets were defined for each site, and flow was calculated for the period of record. The model was calibrated by adjusting parameters including storage, infiltration, runoff, and ground water for three elevation classes (low<800m≤medium<1200m≤high) to fit flow output from model with two USGS gaging stations and one NPS gaging station. The ecohydrologic regimes, characterized using the IHA method, were compared with trout abundance and biomass at each site. Results indicated the abundance of young-of-the-year brook and rainbow trout significantly declined after extreme floods and droughts. In particular, low-flows during droughts significantly reduced recruitment for both brook and rainbow trout, which is likely due to decreased spawning habitat. Brook trout populations in larger low-elevation streams showed more stability compared to smaller headwater streams.
KW - Drought
KW - Flood
KW - Great Smoky Mountains
KW - HSPF
KW - IHA
KW - Trout
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U2 - 10.1061/41036(342)322
DO - 10.1061/41036(342)322
M3 - Conference contribution
AN - SCOPUS:70350150150
SN - 9780784410363
T3 - Proceedings of World Environmental and Water Resources Congress 2009 - World Environmental and Water Resources Congress 2009: Great Rivers
SP - 3186
EP - 3195
BT - Proceedings of World Environmental and Water Resources Congress 2009 - World Environmental and Water Resources Congress 2009
T2 - World Environmental and Water Resources Congress 2009: Great Rivers
Y2 - 17 May 2009 through 21 May 2009
ER -