ARS | Publication request: Influence of riparian habitat on aquatic macroinvertebrate community colonization within riparian zones of agricultural headwater streams

Submitted to: Journal of Freshwater Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 16, 2012
Publication Date: March 21, 2012
Citation: Seger, K.R., Smiley, P.C., King, K.W., Fausey, N.R. 2012. Influence of riparian habitat on aquatic macroinvertebrate community colonization within riparian zones of agricultural headwater streams. Journal of Freshwater Ecology. 27:393-407.

Interpretive Summary: Habitat changes caused by agricultural drainage may alter mosquito populations and aquatic communities within riparian zones bordering agricultural streams. Understanding the effects of these changes will assist with developing riparian zone management guidelines for the numerous small headwater streams that occur throughout agricultural watersheds in the Midwestern United States. Stream channelization to enhance drainage reduced aquatic community diversity and abundance in riparian zones of headwater agricultural streams. Management practices that result in the development of forested riparian zones adjacent to channelized headwater streams will provide ecological benefits. Our results suggest that mosquito larvae control within headwater streams may not be necessary, but adult control within the riparian zones of unchannelized streams may be necessary for control of mosquito-vectored diseases. This information can be used by state, federal, and private agencies responsible for managing agricultural watersheds and restoring streams.

Technical Abstract: Little is known about aquatic macroinvertebrate colonization of aquatic habitats within riparian zones of headwater streams in the Midwestern United States. Many headwater streams and their riparian habitats in this region have been modified for agricultural drainage. Riparian habitat modifications caused by agricultural drainage may influence aquatic macroinvertebrate colonization within the riparian zones of headwater streams. However, the effects of agricultural drainage induced riparian modifications have not been evaluated because others have instead focused on the impact of agricultural drainage on aquatic macroinvertebrates within the streams. We placed water-filled mesocosms in the riparian zones of two channelized and two unchannelized streams in central Ohio and sampled them over a 45 day period from June to August 2009 to determine if differences in physical habitat, water chemistry, and aquatic macroinvertebrate colonization occurred between riparian zone types and among sampling dates. Canopy cover and turbidity were greater in unchannelized riparian zones than channelized riparian zones. Dissolved oxygen was greater in channelized riparian zones than unchannelized riparian zones. Turbidity and nutrients increased from the beginning to the end of the experiment. Macroinvertebrate abundance, taxa richness, and relative abundance of mosquitoes, copepods, cladocerans, and dipterans were greater in unchannelized riparian zones than channelized riparian zones. Temporal trends of zooplankton relative abundance and Shannon diversity index differed between riparian zone types. Aquatic macroinvertebrate abundance, richness, and relative abundance of dipterans increased from the beginning of the experiment to the end. Our results indicate aquatic community colonization in the riparian zones of headwater streams is influenced by riparian habitat type and nutrients. Our results also suggest that stream channelization reduces aquatic community diversity and abundance within the riparian zones of headwater streams in central Ohio.