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Message: <blockquote data-quote="Mysticete" data-source="post: 3592457" data-attributes="member: 67784">Well for starters, I doubt dingos played much role in the big megafaunal extinctions, largely because available evidence suggests that they arrived in Australia long after the first humans, so most likely most of the megafauna was already eradicated. Secondly, there are two main routes that Humans probably snuffed the megafauna in Australia.First, the larger the mammal, the slower the breeder (and this could have been even more enhanced for giant marsupials). If your a diprotodont that maybe only produces one offspring ever few years, it doesn't take much hunting pressure to result in negative population growth. And a good chunk of the megafauna probably would not have been terribly difficult to hunt. Again, a giant diprotodon doesn't have much in the way of defenses, nor were they particularly fast and agile Unlike on the other continents, Australian megafauna never really had to evolve ANY defense again cooperative pack endurance hunters.Loss of several species of megafauna would have had ripple effects. First, large mammals are often keystone species that have a huge effect on their environment. They clear brush and open up habitat, preferentially feed on certain types of vegetation, spread the seeds of some species, and their dung provides important fertilizer. Wiping them out or just significantly reducing them can have a huge effect on the environment, something we have been seeing in Africa recently with the loss of elephants, and which has been used as an explanation for the Pleistocene loss of Arctic steppe habitat and Spruce Parkland, two environments that don't even exist anymore effectively. These environmental changes could have resulted in loss of other species.The second main way proposed that humans could initiate megafaunal extinctions in Australia was through the spread of deliberate use of wildfire for hunting. Beyond just being a pretty destructive way of hunting and resulting in a lot of incidental mortality, continued use of fire can significantly alter the landscape. First, you burn up the topsoil and available nutrients for plant life, especially problematic given that Australia is geologically dead and nutrient poor compared to other continents. Secondly, fire tends to favor species which reproduce using fire, causing replacement by fire prone taxa and loss of the original flora (and even more wildfires). Repeated bouts wildfires can gradually cause desertification...which in turn can alter the local hydrology of an area and cause it to become even drier. As habitat alters, any water sensitive species or herbivores dependent on certain foliage will die off. The Geological record so far supports this above scenario playing out, and suggests that until relatively recently Australia was probably a much wetter and forested place than it is today.As for why giant wombats went extinction but red kangaroos didn't? the simplest answer is one we see demonstrated on all of the other continents as well. Fast and/or hard to catch animals (which is a good description for Kangaroos) generally can survive a megafaunal purge</blockquote>

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