南極洲在變“綠”

張兆勇

隨著全球變暖，南極的氣溫也在逐漸升高，這使得兩種植物在南極大陸上蓬勃生長(zhǎng)。

Rising temperatures over Antarcticas harsh landscape are causing two native plant species to grow well and spread across the continent， according to a recent study published in Current Biology.

Antarctic hair grass， Deschampsia antarctica，and Antarctic pearlwort， Colobanthus quitensis， are the only two native flowering plant species on the southernmost continent. They can resist the continents extremely low temperatures.

Researchers focused their observations on these plants on Signy Island and compared them to extensive records detailing plant growth since the 1960s. The team found that the plants are growing well in a warmer climate. Antarctic pearlwort， a small plant with yellow blossoms， grew five times faster between 2009 and 2018 than growth rates observed between 1960 and 2009. Antarctic hair grass， on the other hand， grew ten times faster in the past decade than in other years.

The team suspects the primary cause of the plants increasing growth rates is warming summer air. Other factors in Antarctica are decreasing fur seal populations. Fewer fur seals on the island mean fewer plants are trampled over.

“The study shows that further increases in populations of these plant species can be expected as Antarctica warms in future decades， leading to the greening of the region， but that there may also be increased risks to ecosystems associated with the establishment of alien plant species，” says Kevin Newsham， an ecologist who wasnt involved in the study.

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What are causing Antarctica to turn green according to the text？ Do you know other reasons except thoes mentioned in the text？