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Megafauna Extinction Debate Narrows Hunting Or Climate

Megafauna Extinction Debate Narrows Hunting Or Climate

What is the oldest argument in Australian science? The argument about what caused the extinction of the Pleistocene megafauna, including the giant kangaroos and marsupial Tapirs, and the uber-echidnas, is probably the oldest in Australian science.

Sir Richard Owen, an English anatomist, suggest in 1877 that big animals driven extinct by the hostile agency of man. This means that hunting was responsible for the extermination of these large animals, a process now known as overkill. Others suggested that climate change was the reason, and it was.

Owen’s view has been support by a series of studies in a variety of disciplines, including geochronology and palaeoecology. The argument does not stop there. But why?

Many Australian archaeologists are against overkill. They’ve search for direct evidence that megafauna kill, but they haven’t found it. There are no large piles of bones in ancient campsites, no diprotodon skulls with spears embedded in their ribs and no arsenal of specialized weapons to bring down large prey. There are very few archaeological sites that have megafauna and human remains in close proximity.

Reality For Some Archaeologists Extinction

Megafauna-hunting was not a reality for some archaeologists. This conclusion is often stated with such confidence that it dismisses any non-archaeological evidence as overkill.

They haven’t asked the crucial question: If megafauna were hunt to extinction by humans, how much evidence should we be able now to find from archaeological sites? According to a new paper, archaeologists Todd Surovell (Brigid Grund) suggest that the answer is either very little or none.

Surovell & Grund first point out that the time period in which archaeological evidence could have found of megafauna being killed is only a fraction of Australia’s total archaeological record. Between 50,000 and 40,000 year ago, people arrived in Australia. This is also when animals such as diprotodon disappeared. Comparing fossil and archaeological dates shows that humans and megafauna spanned only about 4,000 years across continents. Modelling suggests that if there was an extinction due to hunting, it would have occurred in less than 1,000 years.

Australian Archaeological

This means that less than 8% of the Australian archaeological records covers the period of human megafauna interaction. Overkill evidence should be rare, so it is not a smoking gun. Surovell & Grund demonstrate that finding such evidence can be even more difficult than it seems, and for two reasons.

First, the first people to arrive were very few. Therefore, living sites found at low density. Site density increased exponentially as the population grew. The earliest sites are therefore more rare than the later ones.

If megafauna were to have become extinct, the population of megafauna could have declined as people grew. As the number of sites grew, the percentage of them that could have held evidence of megafauna killings was also falling. Sites that could preserve this evidence make up a small percentage of the total archaeological record, possibly less than.01%.

Second, archaeological material is subject to erosion and weathering, and can also broken down and weather. Old sites eventually get bury beneath sediments. It is less likely that archaeological sites can found from Australia’s earliest occupation. Also, most of their contents will have vanished.

The earliest archaeological sites in Australia often only have a handful of stone tools. These tools can only tell us very little about the interaction of the first Australians and any other animals or plants.

North America Extensive Trip Traveling To Canada

North America Extensive Trip Traveling To Canada

Tony Abbott will depart this week on an extensive trip. He will be attending the 70th anniversary of D-Day in France, before traveling to Canada and the United States.

On Wednesday, he will leave the Senate during the parliamentary week. This comes amid ongoing domestic debate over the budget, including controversy surrounding the $7 Medicare copayment and deregulation of university tuition fees. There is also doubt about the fate and future of key measures in Senate.

Seven Australians who were there will join Abbott for the D-Day Commemoration. There were more than 3000 Australians involved, with 2500 personnel from the airforce who provided air support to the Allied Landings.

Business leaders will join Abbott in Canada and the USA, just as he did during his North Asia trip. He will also convey the same message that he did during his North Asia trip. That Australia is open to business.

He Stated That We Welcome New Investment Extensive

He stated that he would promote economic growth while on this trip, with Australia Extensive hosting the G20 summit later in 2012. Barack Obama will meet Abbott for the first time since he became PM. They previously met while Abbott was an opposition leader.

These talks will address a broad range of economic and policy issues. Some interest is being shown in whether climate change gets more attention, given the differing views of the leaders.

Abbott today rescinded a dinner Malcolm Turnbull, cabinet minister, had with Clive Palmer last week. Palmer will soon hold a significant block of Senate votes. Abbott said to Ten that it was perfectly reasonable for senior Coalition members to speak with crossbenchers.

We have a budget that needs to be passed by Parliament. But, before that, we still have the carbon tax absolution to pass and the mining tax abolishition to go through. I am determined to fulfill the fundamental promises we made to the people. The abolition and elimination of the carbon and mining taxes are key to that.

Abbott met last week with crossbenchers that will make him a vital senator. The PUP senators-elect will not deal with the government right now because of a dispute about staffing. Ricky Muir, of the Motoring Enthusiast Party who is aligned to PUP, also declined. He claimed that he couldn’t get off work.

Abbott Described These Conversations As Courtesy Calls

Obviously, I am stressing to them all the government’s absolute determination and will to repeal the carbon tax, the mining tax, and deliver on our promises.

I don’t pretend that any part of this process will not be difficult. Abbott stated that he was certain that Palmer would develop a positive relationship with the government over time.

When asked if Palmer was honest, Abbott replied that it wasn’t his job to provide a character reference to my political rivals and that he wouldn’t. However, I don’t have the right to question the integrity of those who might be our negotiating partners. I expect him openly to speak honestly and openly with the government, and we will be honest and open with him.

American Wolves Can Teach Us Australian Dingoes

American Wolves Can Teach Us Australian Dingoes

Although we know that introduced wolves predators like cats and foxes pose a threat to Australia’s wildlife, what are the best ways to manage them?

Dingoes, according to many Australian ecologists, are part of the solution because they can control feral predators. Although it’s controversial, new research about North American wolves supports this idea.

We have been conducting research through a Fulbright Commission grant to Australia-American Fulbright Commission to better understand dingoes’ role in Australian ecosystems. This done by looking at North American wolves. These results were publish in the Journal of Animal Ecology this week.

Why Are Wolves Important?

As part of predator control programs, wolf were almost exterminate in the United States mainland (except Alaska) during the last two centuries.

However, wolves were reintroduce in Yellowstone National Park and the surrounding areas under the US Endanger Species Act 1995-1996. This law requires that endanger species be restore where possible.

Numerous studies on Yellowstone wolves show that they have a rapid impact on the park ecosystem. They mainly do this by decreasing the prey population.

We are also curious about how wolves interact and co-exist with other predators such as red foxes and coyotes, as wolves continue to recolonize new areas in the United States.

Because wolves are larger predators, we hypothesized that coyotes would be less likely to have wolves as pets. We also hypothesized that coyotes would reduce the number of foxes, so where coyotes are present we should expect more foxes.

These interactions were explore by analysing red fox and coyote fur trapping data in North America, both with and without wolves.

Who Is The Top Dog In This World?

Since the early 1900s, coyotes, red foxes, and wolf have co-existed in Alaska, Yukon, and the NW Territories. The fur-trapping records have shown that coyotes were never more numerous than foxes in areas where wolf live. However, records from areas without wolf are a different story.

Coyotes significantly expand their historical distribution as wolf extinct in many of the lower 48 United States. In the 1970s, coyotes had spread from the middle of America to Maine and New Brunswick to Nova Scotia by 1980.

Although coyotes have only recently colonized Maine, New Brunswick, and Nova Scotia, fur returns data show that it took only 20-30 years for them to outnumber red Foxes, in the absence of wolf.

These results support the idea that wolf can have an impact on smaller predators further down the food chain. These results show that wolves cause a shift in balance across the continent when they were kill off in large parts of the United States. We wanted to find out what happens when coyotes and wolf meet.

This done by analysing fur trapping records from Saskatchewan, Manitoba and central Canada. Both the north and south are home to wolves, while they not found in the provinces. You can see coyotes and wolf in the provinces.

The fur records show that red foxes are outnumber by coyotes in the south, where there are no wolf. This is consistent with our hypothesis. Red foxes are significantly more likely to be present in areas where wolf are absent. With an average of four to one and an extreme of 500:1.

There is however a 200-kilometre transition zone, where there are not enough. Wolves to balance the balance between red foxes and coyotes.

The Magic Number Of Wolves

The possibility that wolf can reduce the number of coyotes could help other species. Such as snowshoe hares and pygmy rabbits, which are at risk from being overrun by them. Montane red Foxes, which have been declining in the presence coyotes, may benefit from the expansion of wolves.

However, the Canadian results show that coyotes may be more likely to be controlled if wolves spread across large areas.

This magical combination is called an ecologically efficient density of wolves. Prior to our study, we didn’t know how many wolves were needed to control coyotes.