Management implications of the relationships between water chemistry and fishes within channelized headwater streams in the midwestern United States

Abstract

Many headwater streams in the midwestern United States were channelized for agricultural drainage. Conservation practices are implemented to reduce nutrient, pesticide, and sediment loadings within these altered streams. The impact of these practices is not well understood because their ecological impacts have not been evaluated and the relationships between water chemistry and fishes are not well understood. We evaluated relationships between water chemistry and fish communities within channelized headwater streams of Cedar Creek, Indiana, and Upper Big Walnut Creek, Ohio. Measurements of water chemistry, hydrology, and fishes have been collected from 20 sites beginning in 2005. Multiple regression analyses indicated that the relationships between water chemistry and fish communities were weak, but significant (P < 0Ð05). Fish communities exhibited negative relationships with ammonium and nitrate plus nitrite and positive relationships with dissolved oxygen, pH, and metolachlor. The strongest observed relationships occurred within those regression models that included a combination of nutrients, herbicides, and physicochemical variables. Multiple regression analyses also indicated that five water chemistry variables exhibited significant relationships (P < 0Ð05) with hydrology. Our results suggest that if water chemistry is the focus of a conservation plan, then the most effective conservation practices may be those that have a combined influence on nutrients, herbicides, and physicochemical variables. Additionally, the use of a combination of conservation practices to address physical habitat and water chemistry degradation is most likely to provide the greatest benefits for fish communities within channelized headwater streams.

A decade of conservation effects assessment research by the USDA Agricultural Research Service: Progress overview and future outlook

“…Invertebrates, fish, and algae are the three components of aquatic ecosystems most recognized by the general public. Although there is an abundance of literature on the effects of conservation practices on agricultural pollutants (Dinnes et al 2002;Hansen et al 2007;Osmond et al 2012), and we can simulate these benefits (Arabi et al 2008), much less has been published on measured ecological responses (Locke et al 2008;Maret et al 2008;Bosch et al 2009;Smiley et al 2009). This implies a working assumption that if agricultural pollutants are reduced aquatic ecology and biodiversity will improve.…”

“…In turn, the increase in primary producer biomass was followed by an increase in fish biomass for two sport fishes, largemouth bass (Micropterus salmoides) and bluegill sunfish (Lepomis macrochirus) (Locke et al 2008). In contrast, despite widespread implementation of conservation practices in two Midwestern watersheds, Cedar Creek and Upper Big Walnut Creek, research showed improvements in physical and chemical water quality had only a minimal influence on stream fish communities (Smiley et al 2009(Smiley et al , 2012. Further research by Smiley et al (2011) indicated that along with improved water quality, improvements in physical habitat would be needed to enhance fish biodiversity in agricultural stream ecosystems.…”

The relative roles of contemporary and ancient processes in shaping genetic variation of a generalist fish in a catchment dominated by agriculture

“…A majority of the land use in the catchment is agricultural, dominated by corn and soybean cropland (The St. Joseph River Watershed Initiative, 2006; Table 2). The Upper Cedar Creek subcatchment (CC) is in the heart of this landscape and its streams are characterised by channelisation, relatively high concentrations of pesticides and fertilisers, sedimentation, an abundance of stream terrestrial vegetation and minimal riparian habitat (Smiley et al, 2009;Deegan, 2010). Here, seven localities were sampled across three channelised streams.…”

The National Sedimentation Laboratory: 50 years of soil and water research in a changing agricultural environment

“…Smiley et al (2009a,b) describe the ecological benefits of various agricultural conservation measures. Smiley et al (2009a) evaluated relationships between water chemistry and fish communities within channelized headwater streams of Cedar Creek, Indiana and Upper Big Walnut Creek, Ohio. Their results suggest that if water chemistry is the focus of a conservation plan, then the most effective conservation practices may be those that have a combined influence on nutrients, herbicides and physicochemical variables.…”