The Earth could be on the brink of the sixth mass extinction in history, claim scientists.They believe that the steep decline in populations of many animal species, from frogs and fish to tigers, is as fast as any of the last five extinctions in the past 540 million years.
科学家声称，地球可能要迎来第六次大规模物种灭绝。他们认为，近年来，许多动物物种数量的急剧减少，像青蛙、鱼类和老虎等等，其锐减速度赶得上过去5亿4千万年以来五次大规模物种灭绝的任意一次。

The study, written by scientists from University of California, will be published in the journal Nature.
此项研究是加利福尼亚大学的科学家撰写，将发表在《自然》杂志上。

"If currently threatened species - those officially classed as critically endangered, endangered and vulnerable - actually went extinct, and that rate of extinction continued, the sixth mass extinction could arrive within as little as 3 to 22 centuries," said Professor Anthony Barnosky.
安东尼•诺维斯基教授表示："如果目前面临灭绝的物种，（包括极危物种、濒危物种和脆弱物种）已经灭亡，而且灭绝速率还在继续，也许在未来的300年，或者2200年，第六次大规模物种灭绝就将到来。"

Nevertheless, Prof Barnosky said it was not too late to save these critically endangered mammals and other such species.
尽管如此，巴诺维斯基教授还表示，现在解救这些濒危哺乳动物和其他濒临灭绝物种为时未晚。

That would require dealing with a perfect storm of threats, including habitat fragmentation, invasive species, disease and global warming.
科学家们认为，物种灭绝速度现在因栖息地的破坏、外来物种的入侵、疾病的增多和全球变暖而加速，这些问题亟待解决。

Biologists estimate that within the past 500 years, at least 80 mammal species have gone extinct out of a starting total of 5,570 species.
此前，生物学家们对过去500年间的物种灭绝速度进行了深入的统计，至少有80种哺乳动物和5570种生物灭绝了。