研究表明，澳大利亞大量動物死于人類和氣候變化

研究表明，澳大利亞大量動物死于人類和氣候變化

Nearly 42,000 years ago, massive animals such as 6-foot-tall birds, 23-foot long lizards and wombat-like creatures the size of a Buick could be seen roaming the countryside. But a new study has found that these megafaunas became extinct because of human intervention and climate change.

大約4萬2千年前，人們可以看到6英尺高的鳥、23英尺長的蜥蜴以及別克大小的袋熊等大型動物在鄉(xiāng)間漫步。但一項新的研究發(fā)現(xiàn)，由于人類的干預和氣候變化，這些巨型動物已經(jīng)滅絕。

The researchers, led by Dr. Frederik Saltre of Flinders University, used a variety of techniques to find human migration patterns in Australia.

弗林德斯大學(Flinders University)的弗雷德里克·薩特博士(Dr. Frederik Saltre)領導的研究人員使用多種技術，在澳大利亞發(fā)現(xiàn)了人類遷徙模式。

“We developed a complex mathematical technique to solve the problems of averaging timelines over landscapes,” he told Fox News. “Our approach extends the information provided by radiocarbon-dated fossils from the extinct species themselves, and archaeological evidence from early Aboriginal people, [and] this way we can create unbiased maps of both the timings of megafauna extinctions and human arrival across the landscape.”

“我們開發(fā)了一種復雜的數(shù)學技術來解決在地形上平均時間線的問題，”他告訴?？怂剐侣劇?ldquo;我們的方法擴展了已滅絕物種的放射性碳年代化石所提供的信息，以及早期原住民的考古證據(jù)，(而且)通過這種方式，我們可以創(chuàng)建無偏倚的地圖，既反映了巨型動物滅絕的時間，也反映了人類到達這片土地的時間。”

Based on these new maps, the team of researchers was able to estimate the regions where humans and megafauna coexisted (for example, New South Wales and north of South Australia), and where they did not (south of Victoria, Tasmania, etc.).

根據(jù)這些新的地圖，研究小組能夠估計出人類和巨型動物共存的區(qū)域(例如，新南威爾士州和南澳大利亞州的北部)，以及它們不共存的區(qū)域(維多利亞州南部、塔斯馬尼亞州等)。

“We then used sophisticated spatial computer models to analyze what conditions – changing temperature, precipitation, freshwater availability, proportion of desert, plant coverage, and the arrival of people – best explained the timing of megafauna extinctions across the landscape,” Saltre added.

“然后，我們使用復雜的空間計算機模型來分析什么條件——不斷變化的溫度、降水、淡水可用性、沙漠比例、植物覆蓋范圍和人類的到來——能夠最好地解釋整個景觀中巨型動物滅絕的時間，”Saltre補充說。

With most of Australia being arid, freshwater was a high priority for megafauna and humans, with its availability being one of the main reasons for people’s migration patterns. Humans and megafauna would inevitably interact at watering holes, leaving the giant animals vulnerable to hunting, further dwindling their numbers.

由于澳大利亞大部分地區(qū)干旱，淡水是大型動物和人類的優(yōu)先選擇，淡水的可獲得性是人們遷移模式的主要原因之一。人類和巨型動物不可避免地會在水坑里相互作用，使得這些巨型動物很容易被捕獵，從而進一步減少它們的數(shù)量。

Saltre, unlike today, these ancient humans did not have an impact on the big dry-out.

Saltre表示，與如今不同，這些古代人類對大干旱沒有影響。

“In regions like Tasmania and south of South Australia and Victoria, humans never coexisted with megafauna because they migrated across these areas after the megafauna had already gone extinct,” he explained. “This rules humans out as the likely driver of megafauna extinction in those regions only, but a closer look at climate change during this extinction event in these areas showed that megafauna species might have suffered from a lack of food availability in the form of plants — most of the species that went extinct were plant-eaters.”

他解釋說:“在塔斯馬尼亞、南澳大利亞南部和維多利亞州等地區(qū)，人類從未與巨型動物共存過，因為它們是在巨型動物滅絕后才遷徙到這些地區(qū)的。””這個規(guī)則,人類只可能在這些地區(qū)司機巨型動物的滅絕,但仔細看看氣候變化在這些領域在這滅絕事件表明,巨型動物物種可能遭受缺乏食物可用性植物的形式——大部分的物種滅絕是食草動物。”

So why was the role of humans in the demise of the Australian megafauna so heavily debated over the years? According to Saltre, up until now, the main ways researchers looked into the causes of megafauna extinction were to build timelines of major events: when the species went extinct; when people arrived; and when the climate changed.

那么，為什么人類在澳大利亞巨型動物的滅絕中所扮演的角色多年來一直備受爭議呢?根據(jù)薩特的說法，到目前為止，研究人員研究巨型動物滅絕原因的主要方法是建立重大事件的時間軸:物種何時滅絕——有人類到達——氣候變化。

However, because there are so few fossilized animal specimens in Australia due to the continent’s harsh conditions, reliable data is scarce. Some studies have been restricted to making conclusions at the scale of single paleontological sites, or of specific archaeological sites, while other studies have taken the opposite approach by including evidence from across the entire continent.

然而，由于澳大利亞大陸的惡劣環(huán)境，動物化石標本非常少，可靠的數(shù)據(jù)很少。一些研究僅限于在單個古生物遺址或特定考古遺址的規(guī)模上得出結論，而另一些研究采取了相反的方法，包括來自整個大陸的證據(jù)。

“Unfortunately, this ‘lumping’ of the available evidence across many different sites ignores the fact that different conditions might be causing extinctions in different combinations depending on where you are in the landscape,” Saltre said.

“不幸的是，這種對許多不同地點現(xiàn)有證據(jù)的‘集中’忽略了一個事實，即不同的環(huán)境可能會導致不同的物種滅絕，具體情況取決于你在景觀中的位置，”Saltre說。

He continued: “This is like either having too few pieces of a jigsaw puzzle to be able to see the big picture (single sites), or being able to see the big picture, but only a fuzzy, pixelated version of it (landscape averaging). Our new approach takes the best of both worlds, because we have now access to all the pieces of the puzzle to unveil the big picture at a good resolution.”

他繼續(xù)說:“這就像要么是拼圖的碎片太少，無法看到大的圖片(單個網(wǎng)站)，要么是只能看到大的圖片，但只有一個模糊的，像素化的版本(風景平均)。我們的新方法是兩全其美，因為我們現(xiàn)在可以接觸到所有的拼圖碎片，從而以一個良好的解決方案來揭開大的圖景。”

The study can be found in Nature Communications.

這項研究發(fā)表在《自然通訊》雜志上。