Event Title

Degraded Habitat and Crowded Niche Space: Understanding Impacts of Habitat Loss and Non-native Fishes on Endemic, Riverine Desert Fishes

Location

Eccles Conference Center

Event Website

http://water.usu.edu/

Start Date

3-29-2011 10:40 AM

End Date

3-29-2011 11:00 AM

Description

The native fishes of the Colorado River basin have experienced dramatic reductions in range due to habitat degradation, hydrograph alteration, and species introductions. Three species of special concern, the flannelmouth sucker (Catostomus latipinnis), bluehead sucker (Catostomus discobolus), and roundtail chub (Gila robusta) typically co-occur and are managed as an ecological unit. The San Rafael River in southeastern Utah is home to populations of each of these species and is a system representative of tributaries of the Green and Colorado Rivers in terms of physical geomorphology and anthropogenic impacts. We investigated how habitat degradation is affecting both the food web and population structure of these native fishes. We sampled physical habitat and biological indicators of food web structure among patches designated as having medium habitat degradation. Overall, CPUE was greatest (mean = 67.38 fishes/hour) in patches designated as having medium habitat degradation. However, CPUE of native fishes was greatest (mean = 37.75 fishes/hour) in reaches experiencing little habitat degradation. Stable isotope analyses indicated that non-native fishes lengthen the food chain and present novel predators and competitors to the three species in the San Rafael River, thus potentially limiting the ability of native fishes to obtain resources necessary for growth and reproduction. These interactions between physical habitat degradation and biotic invasions are reflected in population structure, characterized by source-sink dynamics.

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Mar 29th, 10:40 AM Mar 29th, 11:00 AM

Degraded Habitat and Crowded Niche Space: Understanding Impacts of Habitat Loss and Non-native Fishes on Endemic, Riverine Desert Fishes

Eccles Conference Center

The native fishes of the Colorado River basin have experienced dramatic reductions in range due to habitat degradation, hydrograph alteration, and species introductions. Three species of special concern, the flannelmouth sucker (Catostomus latipinnis), bluehead sucker (Catostomus discobolus), and roundtail chub (Gila robusta) typically co-occur and are managed as an ecological unit. The San Rafael River in southeastern Utah is home to populations of each of these species and is a system representative of tributaries of the Green and Colorado Rivers in terms of physical geomorphology and anthropogenic impacts. We investigated how habitat degradation is affecting both the food web and population structure of these native fishes. We sampled physical habitat and biological indicators of food web structure among patches designated as having medium habitat degradation. Overall, CPUE was greatest (mean = 67.38 fishes/hour) in patches designated as having medium habitat degradation. However, CPUE of native fishes was greatest (mean = 37.75 fishes/hour) in reaches experiencing little habitat degradation. Stable isotope analyses indicated that non-native fishes lengthen the food chain and present novel predators and competitors to the three species in the San Rafael River, thus potentially limiting the ability of native fishes to obtain resources necessary for growth and reproduction. These interactions between physical habitat degradation and biotic invasions are reflected in population structure, characterized by source-sink dynamics.

https://digitalcommons.usu.edu/runoff/2011/AllAbstracts/6