By the early 1800s, many horses introduced to Australia in the late 1700s by European settlers had strayed from or were abandoned by their owners and formed feral herds. Today's Australian brumbies are descendants of these feral European horses. They have adapted to diverse habitats that include open grasslands, semiarid plains and rocky hillsides.
Ecology of the Brumbies
The population of the Australian brumbies is thought to exceed 400,000 horses the figure may expand by as much as 20 percent per year under favorable environmental conditions. Brumbies live in small bands consisting either of one stallion and two to three mares with their foals or of small bands of stallions. They live near permanent water sources but are able to graze up to 50 kilometers away from permanent water sources. There are no major predators for the Australian brumby.
Habitats of the Brumbies
Horses are best adapted to open grassy plains but are found in a wide variety of other environments. In Australia, the brumby horses are found in high numbers grazing prime pasture land reserved for cattle, but they survive quite well in some of the semiarid desert areas. They are wary of humans and have also been known to migrate upward into hilly and rocky areas to avoid contact with humans, as well as to search for food during times of drought.
Preferred Food Sources
The brumby horse primarily consumes grasses but may also selectively browse on roots, bark, fruits and buds. They prefer shorter grasses and selectively graze on that of the highest quality available, preferring oat grasses. They are able to travel further from permanent water sources than cattle, and for this reason they are able to selectively consume a higher-quality feed than cattle living in the same area. During times of drought, many brumby horses perish due to starvation, lack of water or consumption of toxic plants.
Brumby horses have a significant impact on the environments in which they graze. Their hooves are known to compact soil near water sources, which leads to loss of vegetation and soil erosion. Since they have no natural predators, they outcompete other herbivores for food sources and can be destructive to the habitats of smaller wildlife. They spread seeds from agricultural areas into wildlife habitats through their manure, changing local plant populations. They pose a threat to farmers as well, overgrazing range land intended for cattle and bringing diseases to domesticated horses.