Polski
Science, Issue 16/2025
How can climate change disrupt plant reproduction?
Nov
A team of researchers led by Dr. Valentin Journé and Prof. Michal Bogdziewicz of Adam Mickiewicz University in Poznan, Poland, set out to examine how weather events affect cyclical fluctuations in the fertility of trees and shrubs. The study, published in Nature Communications , sheds new light on the impact that climate change may have on plant reproduction, and thus the global biological balance.
Many species of trees and shrubs exhibit the phenomenon of so-called masting – that is, the variable and simultaneous production of seeds by the entire population. This means that one year the plants are sprinkled with fruits, and the next year they hardly bear any. Such irregularity is not an accident. It’s the result of evolution, whereby plants have adapted their reproduction strategy to environmental conditions, especially the weather. Researchers at the UAM analyzed data from 746 populations belonging to 331 perennial plant species to identify the weather phenomena responsible for these cyclical fluctuations in fertility.
Temperature – the language the weather speaks to plants
The most important conclusion of the study confirms earlier speculations: temperature is the main factor that synchronizes years of abundant fruiting. Its effect on seed quantity was on average twice as great as that of rainfall or drought. In temperate and boreal (cool) climate zones, temperature accounted for about 50 percent of the variation in seed production, while rain and moisture deficit each accounted for about 25 percent.
In dry regions, the importance of temperature declined, and humidity and rainfall began to play a key role. In the very humid tropics, on the other hand, periodic water shortages (known as moisture deficit) were more important, and could stimulate flowering through temporary drought stress.
Warm summer, seed year
In temperate climates, abundant fruiting most often followed the previous year’s warm summer – a regularity observed in 77 percent of the species studied. The authors of the article suggest that summer warmth promoted the setting of flower buds and the accumulation of energy reserves needed for later flowering.
In tropical plants, on the other hand, the mechanism was the opposite – flowering was stimulated by periods of cooler temperatures. About 75 percent of tropical species produced more seeds after periods of lower temperatures. Such a phenomenon is observed, among others, in trees of the two-winged family(Dipterocarpaceae) in Southeast Asia, whose flowering depends on rare cool episodes.
The researchers noted that species with an infrequent but abundant seed year show greater sensitivity to temperature fluctuations. In practice, this means that even a small change in weather can cause huge differences in seed production. This hypersensitivity is beneficial when the climate is stable – it allows perfect timing of flowering, which increases pollination efficiency and reduces losses caused by seed eaters. In a changing climate, however, it can prove to be a problem. Plants that are too dependent on the weather easily lose their reproductive rhythm.
Climate and plant reproduction in the future
Although temperature was the dominant determinant of plant fertility, most responded not to a single signal, but to a combination of several weather events. In the temperate zone, as many as 36 percent of species responded to all three factors analyzed – temperature, precipitation and moisture deficiency, compared to only 6 percent in the tropics. This means that in cooler climates, plants read the weather in a more complex way, combining different environmental information.
The relationship between weather and flowering can make global warming seriously disrupt plant reproductive cycles. If warm summers lead to abundant flowering, this signal may occur too often in a steadily warming climate. Plants will not have enough time to accumulate resources between seasons, which will weaken their ability to bear fruit and reduce synchronization in the population.
In contrast, in species that need cool temperatures for flowering, increasingly rare cold episodes can lead to long-term interruptions in reproduction. This is already happening in New Zealand, where the Beilschmiedia tawa tree has almost stopped fruiting as low temperatures there become less frequent.
In Europe, research on beech(Fagus sylvatica) shows that an increase in average summer temperature of just 1°C can increase the number of years encouraging flowering by five times. This, in turn, leads to a decrease in synchrony, greater pest pressure and a drop in healthy seed production of up to 80 percent.
Tropical forests in need
In the tropics, the consequences of climate change may be even more severe. Of the 229 tropical species studied, most required cooler weather to flower. As such periods become less frequent, dramatic declines in fruiting have been observed.
In Lope National Park in Gabon, for example, between 1986 and 2018, the amount of fruit fell by more than 80 percent. Not only plants, but also animals have suffered, including elephants, whose condition has deteriorated due to reduced access to food. Similar trends have been confirmed in 17 other tropical locations, with 22 percent of tree species already showing a decline in fertility.
The researchers found no evidence that the way plants respond to weather is inherited. This means that even closely related species can respond differently to weather, depending on local environmental conditions.
The uncertain future of the world’s flora
The authors point out that despite the huge data set, many of the mechanisms governing plant reproduction are still unclear. It is not known exactly how they sense the weather or which physiological processes are responsible for triggering flowering. Further research combining meteorological data, biological observations and climate models is needed to predict the future of masting.
What is certain, however, is that temperature is a key factor controlling the reproduction of perennial plants, and whether or not its rise promotes flowering depends on the climate zone. In temperate latitudes, warming can lead to disruption of flowering cycles, and in the tropics – to their disappearance.
The sensitivity of plants to weather, which has been their evolutionary advantage for millions of years, may become a weakness today. It is likely that the climate will change more and more rapidly, and then the world may face the phenomenon of a massive decline in tree fruiting, and with it – disruption of entire ecosystems dependent on their seeds.
Source:
Journé, V., Kelly, D., Hacket-Pain, A. et al. Weather drivers of reproductive variability in perennial plants and their implications for climate change risks. Nat Commun 16, 9226 (2025). https://doi.org/10.1038/s41467-025-64300-6
