Peter C. Smiley

Validation of paired watersheds for assessing conservation practices in the Upper Big Walnut Creek watershed, Ohio

Impacts of watershed scale conservation practice adoption on sediment, nutrient, and pesticide losses and adjacent stream biota are not well understood. The objective of this study was to examine the suitability of selected paired watersheds to quantify hydrology, chemical, and ecology effects of conservation practice implementation for channelized and unchannelized watersheds in Upper Big Walnut Creek watershed, Ohio. Channelized watersheds were more similar in watershed characteristics than the unchannelized watersheds. One hydrology, eight water chemistry, and five fish community response variables were measured. Most response variables in both watershed pairs were moderately correlated (r > 0.6), but the minimum percent change required to detect a response difference was greater for the unchannelized watersheds. Detectable temporal trends in the difference between like response variables for the channelized and unchannelized watershed pairs were minimal. These results validate the paired watershed design and suggest that conservation practice induced changes in hydrology, water quality, and fish communities can be quantified.

Vertebrate Use of Habitats Created by Installation of Field-Scale Erosion Control Structures

ABSTRACT Installation of field-scale erosion control structures or drop pipes is a common method for controlling knickpoint gully erosion in fields adjacent to incised streams. These structures transfer runoff water from field level to stream level through a metal drain pipe. The shape of the gully side collection basin at the pipe inlet allows small terrestrial and wetland habitats to develop with associated shallow pools that may be permanently or seasonally flooded. This study evaluated vertebrate use of habitats created by the installation of drop pipes. Four different habitats were categorized based on water depth and surrounding vegetation. Category 1 habitat has the smallest temporary pool, least vegetative structure, and is a terrestrial habitat. Categories consecutively increase to Category 4 which has the deepest pool, most vegetative structure, and is a wetland habitat. Study sites were surveyed for the five major vertebrate classes. Mean species richness and percentage capture abundance for al...

Public health perspectives of channelized and unchannelized headwater streams in central Ohio: a case study

Headwater streams constitute the majority of watersheds in the United States and many in the midwest have been channelized for agricultural drainage. Public health implications of water chemistry and aquatic insects within channelized and unchannelized headwater streams have not been explored. We sampled water chemistry and aquatic insects in two channelized and two unchannelized headwater streams in central Ohio from December 2005 until November 2008. Maximum concentrations of ammonium, nitrate plus nitrite, and chlorothalonil were greater in channelized streams. Nitrate plus nitrite and atrazine also exceeded drinking water standards more often in channelized streams. Maximum concentrations of simazine and the percentage of times it exceeded the drinking water standards were greater in unchannelized streams. The predicted hazard potential of nutrient and pesticide mixtures was greater in channelized streams. Mosquito abundance did not differ between stream types. Chironomid abundance was greater in channelized streams. Biting dipterans did not exhibit consistent abundance trends and only differed between stream types in the summer and fall. Our results suggest that if whole stream uptake of nutrients and pesticides is minimal in channelized headwater streams then nutrient and pesticide inputs from these streams may impact downstream drinking water sources. Our results also suggest channelized and unchannelized headwater streams are not serving as a significant source of mosquitoes.

Influence of riparian habitat on aquatic macroinvertebrate community colonization within riparian zones of agricultural headwater streams

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 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 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 was greater in unchannelized than channelized riparian zones. Dissolved oxygen was greater in channelized than unchannelized riparian zones only during the latter half of the study. Turbidity and nutrients progressively increased throughout the study. Taxa richness was greater in unchannelized than channelized riparian zones. Copepod relative abundance, zooplankton relative abundance, and Shannon diversity index was greater in unchannelized than channelized riparian zones only during the latter half of the study. Abundance, taxa richness, culicid relative abundance, and dipteran relative abundance increased from the beginning of the study to the end. Our results indicate aquatic community colonization in the riparian zones of headwater streams is influenced by riparian habitat type and nutrients.

Differences in aquatic communities between wetlands created by an agricultural water recycling system

Establishment of an agricultural water recycling system known as the wetland reservoir subirrigation system (WRSIS) results in the creation of two different types of wetlands adjacent to agricultural fields. Each WRSIS consists of one treatment wetland designed to process agricultural contaminants (WRSIS wetlands) and one storage wetland for holding subirrigation water (WRSIS reservoirs). Previous WRSIS related research has focused on the filtration ability and development of aquatic plants within WRSIS wetlands. The fauna of the WRSIS reservoirs and how its aquatic community structure compares with WRSIS wetlands is unknown. We compared fish, amphibian, and reptile community structure between WRSIS wetlands and reservoirs in northwestern Ohio. Fishes, amphibians, and reptiles were sampled by seining, hoop netting, and gee minnow trapping in three WRSIS wetlands and three WRSIS reservoirs in June of 2006, 2007, and 2008. No difference in species richness, abundance, percent fish, percent reptiles, fish abundance, or reptile abundance occurred between the smaller shallower WRSIS wetlands and the deeper larger WRSIS reservoirs. Percent amphibians and amphibian abundance was greater in WRSIS wetlands than reservoirs. Jaccard’s index scores ranged from 0 to 0.5 and indicated species composition differed between WRSIS wetlands and reservoirs. Our results assisted with the development of design and management criteria incorporating wetland size, hydrology, and upland habitat intended to enable WRSIS wetlands to function primarily as amphibian habitat and the reservoirs to function as fish habitat.