Title

Monitoring the effects of agriculture on stream biota: small scale irrigation inputs elevate densities of indicator taxa of water quality impairment

Presentation Type

Poster

Abstract

Nutrient enrichment caused by human activities has long been recognized to have significant impacts on the health of aquatic ecosystems. Increases in aquatic nutrient levels typically stimulate the growth of benthic algae with subsequent increases in biological oxygen demand (BOD) and fluctuations in pH as a result of the increased biomass in decomposition. Benthic aquatic invertebrates are commonly used as indicators to assess and monitor these changes in water quality because they are abundant; they are easy to collect; they have life spans long enough to provide a record of environmental conditions; they are relatively sedentary and thus represent local conditions; they are sensitive to pollutants of various types; and they are a critical pathway for the transfer and use of energy in aquatic ecosystems. The purpose of this study is to measure and compare densities of sensitive macroinvertebrate taxa (Ephemeroptera, Plecoptera, Tricoptera or EPT taxa) at irrigation inputs and stream inputs on the Bitterroot River, near Stevenville, MT. Preliminary data from my initial sampling suggests that densities of Tricoptera and Plecoptera are significantly greater downstream of irrigation inputs in comparison to non-irrigation inputs. These data require further replication - I am now sampling downstream and upstream of 3 irrigation inputs and 3 stream inputs. Densities of sensitive EPT taxa at each site will be determined using standard taxonomic keys to the lowest practical level. I will compare the difference between upstream samples and downstream samples to determine whether there is significant variation between macroinvertebrate densities at natural stream inputs versus irrigation inputs. I will measure pH and dissolved oxygen at each site to determine water quality. I predict that, due to nutrient rich runoff from agriculture, macroinvertebrate densities will be greater at irrigation inputs and that these differences can be detected using sensitive EPT taxa as indicators.

This document is currently not available here.

Share

COinS
 
Apr 12th, 11:00 AM Apr 12th, 12:00 PM

Monitoring the effects of agriculture on stream biota: small scale irrigation inputs elevate densities of indicator taxa of water quality impairment

UC Ballroom

Nutrient enrichment caused by human activities has long been recognized to have significant impacts on the health of aquatic ecosystems. Increases in aquatic nutrient levels typically stimulate the growth of benthic algae with subsequent increases in biological oxygen demand (BOD) and fluctuations in pH as a result of the increased biomass in decomposition. Benthic aquatic invertebrates are commonly used as indicators to assess and monitor these changes in water quality because they are abundant; they are easy to collect; they have life spans long enough to provide a record of environmental conditions; they are relatively sedentary and thus represent local conditions; they are sensitive to pollutants of various types; and they are a critical pathway for the transfer and use of energy in aquatic ecosystems. The purpose of this study is to measure and compare densities of sensitive macroinvertebrate taxa (Ephemeroptera, Plecoptera, Tricoptera or EPT taxa) at irrigation inputs and stream inputs on the Bitterroot River, near Stevenville, MT. Preliminary data from my initial sampling suggests that densities of Tricoptera and Plecoptera are significantly greater downstream of irrigation inputs in comparison to non-irrigation inputs. These data require further replication - I am now sampling downstream and upstream of 3 irrigation inputs and 3 stream inputs. Densities of sensitive EPT taxa at each site will be determined using standard taxonomic keys to the lowest practical level. I will compare the difference between upstream samples and downstream samples to determine whether there is significant variation between macroinvertebrate densities at natural stream inputs versus irrigation inputs. I will measure pH and dissolved oxygen at each site to determine water quality. I predict that, due to nutrient rich runoff from agriculture, macroinvertebrate densities will be greater at irrigation inputs and that these differences can be detected using sensitive EPT taxa as indicators.