Restoration implications of the role of physical, chemical, and biotic factors on crayfish injuries in channelized agricultural headwater streams

Authors: Smiley, Peter - Rocky; WOOD, TYLER - Bowling Green State University; GILLESPIE, ROBERT - Indiana University-Purdue University; Gonzalez, Javier; King, Kevin

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Understanding the biota-habitat relationships within agricultural headwater streams in the Midwestern United States will provide information that can assist with developing restoration strategies for these streams. Crayfishes (Order Decapoda) are common inhabitants of agricultural headwater streams in the region. The frequency and severity of injuries within crayfish communities are indicators of levels of crayfish aggression, which is influenced by physical habitat conditions, stress, and crayfish density. Previous studies have not evaluated the determinants of crayfish injuries within agricultural headwater streams. We hypothesized that the frequency and severity of crayfish injuries within agricultural headwater streams would be more strongly influenced by physical habitat and water quality than crayfish density. We sampled crayfishes, documented the frequency and type of injuries, and measured instream habitat and water chemistry in 2014 and 2015 within agricultural headwater streams in northeastern Indiana, southern Michigan, and central Ohio. A linear mixed effect model analysis was conducted to determine if the mean number of injuries per individual, the proportion of injured individuals, the mean number of claw injuries, and the proportion of individuals with multiple injuries were more influenced by physical habitat quality, water quality, or crayfish density. The standardized coefficients from the linear mixed effect model analyses indicated that the four crayfish injury variables were most strongly influenced by crayfish density. We also observed that the crayfish injury variables were positively correlated with crayfish density (P < 0.001) and physical habitat quality (P < 0.05). Our results suggested that within agricultural headwater streams in the Midwestern United States crayfish injuries will be most influenced by restoration practices that alter crayfish density and that crayfish injury response variables may not be effective indicators of physical habitat or water quality.