Horses were first described as pests in Australia in the 1860s. Their environmental impact may include soil loss, compaction, and erosion; trampling of vegetation; reduction in the vastness of plants; increased tree deaths by chewing on bark; damage to bog habitats and waterholes; spreading of invasive weeds; and various detrimental effects on population of native species. In some cases, when feral horses are startled, they may damage infrastructure, including troughs, pipes, and fences. However, brumbies are also credited for helping keep tracks and trails clear for bush walkers and service vehicles in some areas. In recent years, the impact of bushfires has exacerbated the impact of brumbies as native species struggle to adapt to climate change.