Scott Gibbons/GettyFrom poems to films and books of history, horses feature widely in Australian popular culture.Feral horses, also known as brumbies, are descendants of domesticated horses that now live and breed independently in the wild. For some people, these horses are a cherished part of Australia’s cultural heritage. For others, they represent a major threat to the environments they inhabit.Yuraygir National Park, on the coast of northern New South Wales on Yaegl and Gumbaynggirr Country, is a stunning landscape where you can see coastal emus and spot migrating whales from the shore. It is also home to a small feral horse population that is now at the centre of a legal dispute. The final hearing, taking place on Wednesday, could have repercussions far beyond feral horses. Yuraygir is home to the largest population of coastal emus left in Australia. David Watson What is this dispute about?In late August, feral horse advocates began urgent proceedings in the NSW Land and Environment Court. They argued the National Parks and Wildlife Service does not have the legal authority to kill feral horses in Yuraygir.The National Parks and Wildlife Service had been using aerial shooting, ground shooting and trapping to manage feral horses, as well as feral pigs, deer and foxes. It has now agreed to suspend activities until the final hearing on September 9. To date, the court has not ruled the proposed operations are unlawful. Rather, the current suspension gives the NSW Department of Climate Change, Energy, the Environment and Water time to ensure necessary approvals are in place so staff can continue working towards the goals of the Yuraygir management plan. These include controlling feral animals and restoring native vegetation. A herd of feral horses, also known as brumbies. Skitzpix/Getty A controversial topicFeral horse control has long been a source of heated debate. For many people, it is more controversial than the management of other invasive species, such as deer and foxes, because horses are more culturally cherished. Lethal control is also associated with animal welfare concerns, including stress during pursuit and the possible risk of non-fatal wounding.However, there is a strong ecological case for controlling feral horses. As large, hard-hooved, introduced grazing animals, feral horses can inflict significant damage to Australian ecosystems. They trample plants, compact soils, erode stream banks and disturb wetlands. This endangers many native species that rely on these fragile habitats, some of which live nowhere else. So feral horses must be managed with the same planning and urgency as other invasive animals.Evidence suggests aerial shooting by professionals under strict protocols does not affect the welfare of feral horses. For example, independent veterinary assessments of recent operations in Kosciuszko National Park uncovered no welfare-related incidents.A park worth protectingYuraygir National Park encompasses an extensive network of coastal lagoons, freshwater wetlands, saltmarshes and wet heaths that support an array of threatened animals. This includes the green and golden bell frog (Litoria aurea), the wallum froglet (Crinia tinnula) and the Olongburra frog (Litoria olongburensis).However, these environments are among those most vulnerable to grazing and trampling. This is because their soft, often waterlogged soils and delicate vegetation are easily damaged by hard hooves. Feral horses can compact and churn up soil, increase erosion and muddy water, while destroying the shallow pools and vegetation that frogs use for shelter and breeding.Beyond frogs, feral horses trample the nesting grounds of threatened shorebirds, such as the little tern (Sternula albifrons), pied oystercatcher (Haematopus longirostris) and critically endangered beach stone-curlew (Esacus magnirostris). Because these birds nest in shallow scrapes on the ground, horses could crush eggs or chicks and disturb nesting adults. Grazing and trampling may also reduce the dense vegetation relied on by species such as the eastern ground parrot (Pezoporus wallicus wallicus).The current shooting suspension also delays control of pigs, deer and foxes, other invasive species that damage wetlands and native vegetation or prey on native wildlife. Yuraygir’s management plan identifies fox control as vital to protecting little terns, beach stone-curlews and coastal emu chicks. So this legal dispute, while focused on feral horses, may have much broader ecological costs. Yuraygir National Park is home to the endangered green and golden bell frog. Gerald Corsi/Getty Early action is keyControl may seem unnecessary given there are relatively few horses in Yuraygir. However, research suggests the opposite is true.Studies consistently show it’s often easier and cheaper to control small, localised populations of invasive species than larger, widespread populations. Delaying action gives animals time to reproduce, establish new populations and expand their geographical range. Management then becomes more difficult and expensive. It is also more likely to require repeated killing.Kosciuszko is a case in point. Since late 2023, when aerial shooting was reintroduced to Kosciuszko National Park, thousands of feral horses have been removed. However, population numbers have stayed high and ecological damage remains widespread. This is partly because horses can breed quickly and move into controlled areas from surrounding land, particularly when management pauses.There is still time to stop this happening at Yuraygir. For now, we await a decision from the NSW Land and Environment Court. But to safeguard this sacred landscape, we must protect it from the hard hooves and hungry mouths of feral horses. A wild beach stone-curlew wading in an estuary. Kristian Bell/Getty Patt is the director for early career ecology at the Ecological Society of Australia, the Early Career Coordinator at the Australasian Wildlife Management Society, and a council member for the Royal Zoological Society of NSW. He receives funding from the Australian Research Council.David M Watson receives funding from the Australian Research Council, the Department of Agriculture, Fisheries and Forestry and the Department of Climate Change, Energy, the Environment and Water. He also serves as a board member for the Great Eastern Ranges and the Holbrook Landcare Network.