Changes in climate affect the timings of various points in the life cycle of plants, including when flowers bloom in spring and when leaves wither in autumn. 

氣候中的諸多變化影響植物生命週期中，不同時間點的時序，包括於春季何時開花及於秋季何時葉子枯萎。

“Si sta come d’autunno sugli alberi le foglie.”

“感覺就像樹上的秋葉。”

“We are like autumn leaves on branches,” Italian poet Giuseppe Ungaretti wrote in his 1918 poem Soldati (Soldiers), on the tragedy of human life and war. on the tragedy of human life and war.

“我們就像樹枝上的秋葉，”意大利詩人Giuseppe Ungaretti，在其1918年，有關人類生活與戰爭的悲劇詩Soldati (士兵們)中，記述：「我們就像樹枝上的秋葉。」

If the popular image of autumn is decadence and nostalgia after the summer heat, spring is the season of rebirth after the darkness and cold of winter. The transformative passing of seasons has historically represented a powerful mental image, rich in symbolism. The seasonal timings of biological events are also an essential aspect of plant adaptation and can also be of crucial economic relevance.倘若秋天的普遍形像是，夏日炎熱後的頹廢與懷舊，那麼春天是冬天黑暗與寒冷後的重生季節。季節之有改造作用的順利進行，以往一直代表一種，存在於腦中的強大映像，富有象徵意義。生物成長進程的季節性時序，也是植物適應的一個重要層面，也會有至關重要的經濟關聯性。

However, as forest ecologists, we have observed that climate change has been modifying the timing of recurrent plant life-cycle events, thus critically affecting the ecosystem.

然而，身為森林生態學家，我們已經觀察到，氣候變遷一直在改變，植物生命週期的進程時序，從而嚴重地影響生態體系。

In spring, flowers bloom. In summer, fruits ripen. In autumn, leaves change colour and fall. In winter, plants rest. This is phenology — the study of the timing of recurring life-cycle events.

在春天，鮮花盛開。在夏天，果實成熟。在秋天，葉子變色、落下。在冬天，植物休眠。這是研究，循環性生命週期之進程時序的物候學(也就是，研究生物周期現象與氣候的相互關係)。

So how do plants recognize the passage of time and the right moment to accomplish growth and reproduction? Like people, plants have their own calendar. A plant’s clock is represented by cycles in the environmental conditions, and the timing of phenological events is controlled by climate.

那麼植物如何確認時間的推移，及完成生長與繁殖的適當時機？與人類一樣，植物也有其自己的行事曆。植物的時鐘是由環境條件中的周期所呈現，而物候關係的時序是由氣候所控制。

Specifically, plants use a set of triggers to synchronize the timings of growth and reproduction with favourable environmental conditions.

具體而言，植物使用一套觸發物，來使生長及繁殖的時序與有利的環境條件進行同步。

Depending on the species, phenological events are triggered by temperature (autumn and winter chilling and spring warming), photoperiod (length of day), precipitation or, often, a combination of these.

取決於物種，物候關係的進程是由溫度(秋天及冬天變冷，而春天變暖)、光週期(一天的長度)、降雨，或往往是這些的組合所觸發。

Phenology is one of the most sensitive biological indicators of the changing climate. Under the progressive rise in temperature experienced in the last century and the variations in seasonal distribution of rainfall events, the environmental triggers usually occur earlier and earlier.

物候關係是氣候變遷最敏感的生物指標之一。於上個世紀中，在溫度上經歷漸進的升高，及在降雨事件之季節性分佈方面的變化下，此些環境的觸發，通常越來越早發生。

This is why phenological shifts have been observed worldwide, and contextually, it seems that phenological events are occuring earlier year by year.

這是為何遍及全世界，已經被觀察到之物候關係變化的原因。因此，從上下文來看，物候關係的事件似乎正逐年較早發生。

Japan’s Sakura or cherry blossom season is one of the most evident proofs of this shift. Dating back to the ninth century, the date of flowering, which defines the festival’s timing, has been anticipated in the last century by the rise in average temperatures.

日本的櫻花，也就是櫻花季節，是這種轉變最明顯的證據之一。回溯到九世紀，決定節慶活動之時間安排的開花日期，在上個世紀，因平均溫度上升，已經被預期。

American poet Anne Bradstreet said, “If we had no winter, the spring would not be so pleasant.” While this is hyperbolic, we still need to consider that the timings of flowers blooming, fruits ripening and other such phenological events result from a long-lasting adaptation of each species to its surrounding environment.

美國詩人Anne Bradstreet宣稱：「倘若沒有冬天，則春天不會那麼宜人。」儘管這是誇張的，不過我們仍然需要思考，花朵盛開、果實成熟及其他起因於，每一物種對其周遭環境之長期適應的此類物候關係事件。

圖1. 環境變化會產生經濟後果，因為它影響農業及林業產品的數量與質量。  (圖援用自原文)

The timing of phenological events are calibrated to ensure the perfect environmental condition needed to accomplish the annual cycles of a plant’s life while minimizing the risk of damage. Changes in these conditions can have ecological as well as economic consequences as they can affect the quantity and quality of agriculture and forestry products.

物候關係事件的時機掌握經過調整，以確保達成植物生命之每年週期所需的完美環境條件，同時將損害風險降至最低。這些條件的變化會具有，生態及經濟上的後果。因為，它們會影響農、林產品的數量與品質。

At the end of the growing season, plants develop dormant buds to protect the sensitive meristematic cell layer — tissue in which cells maintain the ability to divide throughout the life of the plant — and suspend activity. Dormancy is an adaptation mechanism evolved in climates with seasons to escape harsh winter conditions.

在生長季節結束時，植物生長出休眠芽，來保護敏感的分生組織細胞層(在植物的整個生命中，細胞保持分裂能力的組織)及暫停活動。休眠是一種，在具有季節之氣候中，演化來規避嚴寒冬季條件的適應機制。

Warm spring temperatures (called forcing), the increase in day length during spring (photoperiod), and the length and intensity of winter temperatures (chilling) reactivate the growth of the apical buds — the buds located at the top of the plant — in the spring.

暖和的春季溫度(被稱為促成)、春季期間白天長度的增加(光週期)及冬季溫度的長度與強度(變冷)，在春天重新激活頂端芽(位於植物頂部之芽)的生長。

Clearly, temperature has a central and leading role in this process. For this reason, warming can trigger an earlier reactivation in spring and a delayed cessation in autumn, or both, lengthening the growing season.

顯然，溫度在這個過程中，具有核心及主導角色。就此原因，於春季，暖化會觸發較早的重新激活，而秋季延遲停止，或兼具兩者，從而延長生長季節。

Some believe that a longer growing season could enhance carbon uptake and, therefore, the productivity of forests. In some places, such as regions in the northern latitudes or elevated altitudes, trees have profited from a longer growing season and, more generally, more favourable climatic conditions under global warming.

有些人認為，較長的生長季節能提高碳吸收，及因此提高森林的生產力。在某些地方，諸如北方的緯地區或高海拔地區，樹木一直從較長的生長季節，及更普遍的是，在全球暖化之更有利的氣候條件下，獲益。

圖2. 於春季的晚霜及秋季的早霜，通常伴隨較長的生長季節，增加了對植物及樹木的損害風險。  (圖援用自原文)

However, an earlier growth reactivation increases the risk of damage due to late spring frosts, and lengthening of the growing season increases the risk of damage by early autumn frosts.

然而，較早重新激活生長會增加，由於晚春霜凍造成損害的風險，而延長生長季節會增加，因早秋霜凍造成損害的風險。

If trees cannot adapt, or re-adapt, their phenology with the new climatic conditions, the fitness and growth performance of local populations could be dramatically affected.

倘若樹木不能適應(或重新適應)其具有新氣候條件的物候關係，則當地種群的適應性及生長表現，可能會顯著受到影響。

Ecosystems are generally complex and the species within them interact with each other as well as their surrounding environment. Different species can react differently to the changing climatic conditions, potentially leading to dangerous new phenological matches or mismatches.

通常，生態體系很複雜。亦即，除了其周遭環境之外，於其中的物種也互相交互影響。對於變化的氣候條件，不同的物種會不同地作出反應。潛在上，會導致危險之新物候關係的匹配或不匹配。

For example, current climatic conditions create new phenological matches between prey and predators.  Black spruce may become a key host for the spruce budworm given that the timing of maximum larvae activity could be better synchonized with the timing of yearly shoots development, which increases the risk of severe defoliations for one of the most profitable boreal species in North America.

譬如，當前的氣候條件，在獵物與捕食者之間，創造了新物候關係的匹配。黑雲杉可能成為雲杉芽蟲的主要寄主，鑑於最大的幼蟲活動時機與每年新芽發育時機會是更佳地進行同步。對在北美最有用的北方物種之一而言，這增加了嚴重落葉的風險。

Climate change can also cause mismatches between plants and their pollinators. Bumblebees represent one of the most important pollinators for several wild species and many varieties of enormous agricultural interest. Bumblebees, given their low heat and cold tolerance, are particularly sensitive to environmental conditions. For this reason, the projected climatic risk for this species is extremely high.

氣候變遷也導致植物與其傳粉者之間的不匹配。大黃蜂代表了，對若干野生物種及諸多具巨大農業利益的種類而言，是最重要的傳粉媒介之一。鑑於大黃蜂低的冷、熱耐受性，其對環境條件特別敏感。就此理由，該物種的預期氣候風險非常高。

圖3. 大黃蜂對氣候變遷極為敏感。  (圖援用自原文)

The mutually beneficial plant-pollinator relationship is an essential ecosystem service, specially considering that the pollination done by insects contributes to 9.5 per cent of global food production.

這種相互有益之植物-授粉者的關係是一項，不可或缺之生態體系的益處。特別是，思考由昆蟲進行授粉，促成9.5%的全球糧食生產量。

As the climate continues to change, affecting all kinds of ecosystems in the process, we need to be aware of plant phenology and think about how these shifts may directly affect our lives and businesses.

隨著氣候持續變遷，在此過程中，影響著各種生態體系，我們必需瞭解植物的物候關係，並思考此些變化會如何直接影響我們的生活及事業。

Scientists, today, use observational data to determine how species, populations and communities are vulnerable to these ongoing and projected future changes in climate.

目前，科學家們使用觀測的數據，來確認在氣候上，物種、種群及社區，如何容易受到此些進行中，及預計於未來之變遷的影響。

This research can be the foundation for essential human intervention, which may influence plant distribution through assisted migration, which is the human-assisted movement of species to areas far outside their established range. This will help tree species resynchronize their phenology to the current climatic condition.

這項研究會是，必需之人類介入的基礎，這可能透過協助的遷移，來影響植物分佈。這是物種經人類協助，遷移到遠離其既定範圍的區域。這將有助於樹種，將其物候關係與當前的氣候條件重新進行同步。

Plant phenology is the result of an adaptation. However, adaptation requires time, an amount of time we do not have given the magnitude and rate at which we are observing climate changes. Constantly monitoring the phenological shifts worldwide will allow us to develop sound strategies to protect the most vulnerable ecosystems as well as our businesses.

植物物候關係是一種適應的結果。然而，適應需要時間，在我們正進行的氣候變遷觀察中，我們沒有已知之幅度及速度的時間量。不斷地監測全球物候關係的變化，能使我們得以制定健全的策略，來保護此些最脆弱的生態體系及我們的事業。

Besides, we are like autumn leaves on branches, but at least we should try not to fall!

此外，我們像是樹枝上的秋葉。不過，至少我們應該嘗試不落下！

網址：https://theconversation.com/climate-change-is-altering-the-seasonal-rhythm-of-plant-life-cycle-events-181231

翻譯：許東榮