Feral horses, or brumbies as they are commonly known, are an invasive species in Australia.
With helicopter shooting currently banned in Queensland and New South Wales, and general opposition to lethal control, property managers are looking for new methods of deterring feral horses from their land.
“Management of feral horses is an increasing problem for property owners and protected area management alike,” she said.
Ms Joseph, who has just submitted her PhD thesis on equine behaviour and feral horse management, has tested a range of potential repellents for small scale exclusion of feral horses from refuge habitats for native wildlife.
She also measured behavioural indicators of stress in both domestic and feral horses in an attempt to identify the most humane control method.
Changes in heart rate and behaviours such as vocalisation, defecation rate, and gait were used as benchmarks to measure the stress levels of feral horses in the field.
“The research aims to gain a better understanding of the underlying mechanisms of fear and repellency in horses,” she said.
“It tests the theory that fear-provoking stimuli are more effective repellents, and I also developed a novel screening method to compare repellents without undertaking costly field trials.”
The University’s domestic horses were initially used to screen 23 repellents, which were divided into three groups – visuals, sounds, and smells.
Ms Joseph said that sound stimuli consistently caused the strongest reaction, followed by visual stimuli, with smells being the least repellent.
“This is especially interesting in light of the fact that most commercially available herbivore repellents are either smell or taste-based,” she said.
Ms Joseph, who has been an avid horseback rider since childhood, came to Australia from California to study three years ago.
“My general research goal is to improve wildlife conservation through a better understanding of animal behaviour. I hadn’t planned on studying horses for my PhD, but this project allowed me to combine several of my passions, which was ideal.”
Ms Joseph completed her undergraduate in wildlife, fish and conservation biology at the University of California, Davis, before undertaking her PhD in Australia.
“My fascination with Australian wildlife began as a child, and I was determined to do my PhD here,” she said.
“I eventually chose The University of Queensland because I was given the freedom and support to study exactly what I wanted, despite it being a somewhat controversial topic. It is a rare opportunity for which I am very grateful.”
Ms Joseph hopes that her research results will pave the way for future deterrence systems and techniques.
Having completed this project, Ms Joseph said she was now well on her way to achieving her goal of becoming a researcher and scriptwriter for wildlife documentaries.