Hall, P. T. | Search bioRxiv

bioRxiv2022

Rabbit hindlimb kinematics and ground contact pressure during the stance phase of hopping gait

Though the rabbit is a common animal model in musculoskeletal research, there is very limited data reported on healthy rabbit biomechanics. Our objective was to quantify the normative hindlimb biomechanics of six New Zealand White rabbits (3 male, 3 female) during the stance phase of hopping gait. We measured biomechanics by synchronously recording sagittal plane motion and ground contact pressure using a video camera and pressure mat, respectively. Both foot angle (i.e., angle between foot and ground) and ankle angle curves were unimodal. The peak ankle dorsiflexion angle was 65.9{degrees}{+/-}12.7{degrees} and occurred at 39% stance, while the peak ankle plantarflexion angle was 136.9{degrees}{+/-}7.8{degrees} at toe-off. Minimum and maximum foot angles were 16.6{degrees}{+/-}6.4{degrees} at 12% stance and 125.4{degrees}{+/-}4.0{degrees} at toe-off, respectively. During stance, the knee joint center gradually progressed 4.7 cm downward and 18.1 cm forward, on average. The maximum vertical ground reaction force and contact area, both averaged across rabbits, were 42.5 {+/-} 11.4 %BW and 7.5 {+/-} 1.8 cm2, respectively. Our study confirmed that rabbits exhibit a plantigrade gait pattern, similar to humans. Future studies can reference our data to quantify the extent to which orthopedic interventions affect rabbit biomechanics.

systems biology↗

bioRxiv2021

An efficient method of evaluating multiple concurrent management actions on invasive populations

Evaluation of the efficacy of management actions to control invasive species is crucial for maintaining funding and to provide feedback for the continual improvement of management efficiency. However, it is often difficult to assess the efficacy of control methods due to limited resources for monitoring. Many managers view effort on monitoring as effort taken away from performing management actions. We developed a method to estimate invasive species abundance, evaluate management effectiveness, and evaluate population growth overtime from a combination of removal activities (e.g., aerial gunning, trapping, ground shooting) using only data collected during removal efforts (the method of removal, the date, location, number of animals removed, and the effort). This dynamic approach allows for estimating abundance at discrete time points and the estimation of population growth between removal periods. We applied this method to removal data from Mingo National Wildlife Refuge in Missouri from December 2015 to September 2019, where the management objective is elimination. Populations of feral swine on Mingo NWR have fluctuated over time but showed more marked declines in the last 3-6 months of the time series. More dramatic declines were observed in the center of the refuge likely aided by reducing potential immigration from the rest of the refuge. To counteract population growth (from both births and immigration) the percent of the population of feral swine removed monthly must be greater than the growth rate. On average, we found that removing 10% of the population monthly had only a 50% chance of causing a population decline, whereas removing 15% of the population monthly had a 95% chance of causing a population decline. Our method provides advancement over traditional removal modeling approaches because it can be applied to evaluate management programs that use a broad range of removal techniques concurrently and whose management effort and spatial coverage vary across time.

ecology↗