英国の植物、１か月早く開花　温暖化の影響

【パリＡＦＰ＝時事】英国で、地球温暖化の影響により植物の開花時期が約１か月早まっていることが、２日公表の研究で分かった。農作物や野生動物への影響が懸念される。（写真は資料写真）
　論文は英学術専門誌「英国王立協会紀要Ｂ」に掲載された。
　研究では、開花時期の推移を調べるため「自然カレンダー」と呼ばれるデータベースを使用した。自然カレンダーは、科学者、博物学者、ガーデニング愛好家や庭師、英国王立気象学会などの団体から寄せられた観測情報をまとめたもので、２００年以上前から運用されている。
　国内の高木や低木、薬草、ツル性植物など４０６種の観察記録４０万件以上を調べた結果、１９８７～２０１９年の平均開花日は、１７５３～１９８６年に比べ３０日早くなっていたことが分かった。
　研究を率いたケンブリッジ大学のウルフ・ビュントゲン教授は、開花時期が早まると生態系が壊れる恐れがあり、「実に憂慮すべき」結果だと指摘した。
　農作物が早く開花すると遅霜の被害を受ける可能性がある。ただ、最も脅威にさらされるのは野生動物だという。
　昆虫や鳥は、餌である植物と発育段階が同時期になるように進化してきた。この時期がずれると「生態系のミスマッチ」が起こる。
　ビュントゲン氏は大学の発表で、ある植物の花が咲くと特定の昆虫が引き寄せられ、その昆虫が特定の鳥を呼び寄せるといった連鎖があると説明した。構成要素の一つの発達が他よりも早くなってしまうと、連鎖がずれてしまう恐れがある。ずれに対する適応が間に合わなければ、種の絶滅につながる可能性もあるという。
　ここ数十年の開花時期の推移は、特に温暖化など人間の活動による気候変動の影響の加速と一致する。
　国連は先月、過去７年は史上最も暑かったと発表した。２０２１年の世界の平均気温は、産業革命以前の１８５０～１９００年の気温を約１．１１度上回った。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2022/02/03-10:41）

Global warming is causing plants in the UK to burst into flower around a month earlier, with potentially profound consequences for crops and wildlife, according to research Wednesday that used nature observations going back to the 1700s.
Trees, herbs and other flowering plants have shifted seasonal rhythms as temperatures have increased, according to the study led by the University of Cambridge.
The results are truly alarming because of the ecological threats posed by early flowering, said Ulf Buntgen, a professor from Cambridge's Department of Geography, who led the research published in the journal Proceedings of the Royal Society B.
Crops can be killed off if they blossom early and are then lashed by a late frost, but reasearchers said the bigger threat was to wildlife.
This is because insects and birds have evolved to synchronise their own development stages with the plants they rely on. When they are no longer in phase, the result is an ecological mismatch.
A certain plant flowers, it attracts a particular type of insect, which attracts a particular type of bird, and so on, Buntgen said in a press release from the university.
But if one component responds faster than the others, there's a risk that they'll be out of synch, which can lead species to collapse if they can't adapt quickly enough.
- Spring backwards? -
To track the changes in flowering patterns, researchers used a database known as Nature's Calendar, which has entries by scientists, naturalists, amateur and professional gardeners, as well as organisations such as the Royal Meteorological Society, going back more than 200 years.
Looking at more than 400,000 observations of 406 trees, shrubs, herbs and climbing plants across swathes of Britain, they found that the average first flowering date from 1987 to 2019 is 30 days earlier than the average first flowering date from 1753 to 1986.
The changes seen in recent decades coincide with accelerating impacts of human-caused climate change, especially higher temperatures.
Spring in Britain might eventually creep into the historically wintry month of February if global temperatures continue to increase at their current rate, said Buntgen.
That rapid shift in natural cycles could reverberate through forests, farms and gardens.
Buntgen said scientists need to have access to data that track whole ecosystems over long periods of time, if we are to truly understand the implications of climate change.
We can use a wide range of environmental datasets to see how climate change is affecting different species, but most records we have only consider one or a handful of species in a relatively small area, said Buntgen.
There is growing concern among scientists about the scale of the impact of a rapidly warming world, on everything from extreme weather events to loss of biodiversity.
The United Nations last month confirmed that the past seven years have been the hottest on record, while the average global temperature in 2021 was around 1.11 degrees Celsius above the pre-industrial levels measured between 1850 and 1900.