世界の樹種、３分の１以上が絶滅の危機 ＩＵＣＮレッドリスト

【カリ（コロンビア）ＡＦＰ＝時事】国際自然保護連合（ＩＵＣＮ）は２８日、世界中で確認されている樹種の３分の１以上が絶滅の危機にひんしているとするレッドリスト（絶滅の恐れのある野生生物種のリスト）の最新版を発表した。（写真はユーカリの木。資料写真）
　ＩＵＣＮは、コロンビア・カリで開かれている国連（ＵＮ）の生物多様性条約締約国会議（ＣＯＰ１６）に合わせてレッドリストを報告。
　世界には約５万８０００種の樹木が存在すると考えられているが、今回の調査では４万７０００種以上が評価対象となった。このうち３分の１以上に相当する１万６０００種以上が絶滅の危機にひんしているという。
　樹木の伐採や農地開拓、都市開発などにより森林破壊が進み、さらに気候変動によって干ばつや山火事も深刻化している。
　樹木の減少は単なる象徴的なものではなく、専門家のエミリー・ビーチ氏が指摘するように、人間は「食料、木材、燃料、医薬品としても樹木に頼っている」。
　樹木はまた酸素を生成し、大気中に存在する温室効果ガスの一種である二酸化炭素（ＣＯ２）を吸収している。
　ＩＵＣＮのグレーテル・アギラル事務局長は、「大勢の人間の生活と生計を樹木が支えている」とし、「樹木は生態系において、その重要な役割を通じて地球上の生命を維持するために必要不可欠だ」と訴えた。
　報告書は、植樹による森林保護と回復、種子銀行や植物園のコレクションによる絶滅危惧種の保護を呼び掛けている。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2024/10/29-20:23）

More than one in three species of trees are at risk of extinction worldwide, threatening life as we know it on Earth, according to a report published Monday.
The warning came in the Global Tree Assessment, contained in an update of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species.
Issued to coincide with the UN's COP16 summit on biodiversity, held in the Colombian city of Cali, the report said over 16,000 tree species are at risk of extinction.
More than 47,000 species were assessed for the study, out of an estimated 58,000 species thought to exist in the world.
Trees are felled for logging and to clear land for farming and human expansion. Climate change poses an additional threat through worsening drought and wildfires.
The numbers are not merely symbolic.
People rely on tree species for food, timber, fuels (and) medicines, expert Emily Beech told AFP.
They also make the oxygen we breathe, and absorb heat-trapping carbon dioxide emissions from the atmosphere.
Trees are essential to support life on Earth through their vital role in ecosystems, and millions of people depend upon them for their lives and livelihoods, said IUCN director general Grethel Aguilar.
A 2015 study estimated there are about three trillion individual trees in the world.
The study, published in the science journal Nature, estimated that over 15 billion trees are cut down each year, and the global number of trees has fallen by nearly half since the start of human civilization.
Over 5,000 of the species on the IUCN Red List are used for construction timber, and more than 2,000 species for medicines, food and fuels.
Species at risk include the horse chestnut and ginkgo, both used for medical applications, the big leaf mahogany used in furniture making, as well as several ash, magnolia and eucalypt species, said Beech, head of conservation prioritization at Botanic Gardens Conservation International (BGCI), which contributed to the tree assessment.
- Seed banks essential -
According to the IUCN report, the number of trees at risk is more than double the number of all threatened birds, mammals, reptiles and amphibians combined.
Tree species are at risk of extinction in 192 countries, but the highest proportion is found on islands due to rapid urban development and expanding agriculture, and the introduction of invasive species, pests and diseases from elsewhere.
In South America, which boasts the greatest diversity of trees in the world, 3,356 out of 13,668 assessed species are at risk of extinction.
Many species on the continent, home to the Amazon jungle, have likely not even been discovered yet.
When they are, they are more likely than not to be threatened with extinction, said the report.
It called for forest protection and restoration through tree planting as well as the conservation of species dying out through seed banks and botanic garden collections.
More than 1,000 experts contributed to the assessment.