In a new and particularly comprehensive British study, it was found that the spring blossoms in the country arrive a month earlier on average compared to the situation in the past
By Yonatan Sher, Zveta - news agency for science and the environment
If you took a nap that day in the garden, you might be surprised to hear that the Passover holiday has 5 names: Passover, Unleavened Bread, Harut, Redemption and Spring. However, given the increasing trend in recent decades, it may be that Passover will soon have to say goodbye to the last name on the list: bNew British research And particularly comprehensive, it was found that the spring flowering in the country precedes its arrival by a month on average compared to the situation in Gab
One of the things that makes the new study unique is the large amount of data included in it: it reviews 419,354 observations, which recorded the first flowering dates of 406 plant species over hundreds of years: from 1753 to 2019. These plants include 334 grass species, 44 Tree species, 25 shrub species and 3 climbing plant species. The observations were divided into two time periods - until 1986, and from 1987 onwards.
The researchers found that according to the observations, the first flowering date was 26 days earlier on average in the period between 2019-1987 compared to the period between 1986-1753. In fact, between the years 2019-1952, the flowering dates advanced by an average of 5.4 days each decade.
The researchers discovered variation within the different groups of plants and between different regions in the degree of advance of flowering. Plants flowered almost a week earlier in low areas compared to high areas, in urban areas compared to rural areas and in the south of the country compared to the north. The change in flowering dates was most significant in grasses (whose average advance in blooming was 32 days), compared to trees and shrubs, and according to the researchers, the reason for this may be that plants such as grasses, which live a relatively short time, are able to adapt evolutionarily more quickly to the changing climatic conditions.
The researchers also examined accurate meteorological data from the studied area, and found that the factor that most influences the time of flowering is the average daily maximum temperature in the months of January-April (and not the amount of precipitation, or the snowmelt times in the area). According to them, the fact that the average temperature in the world has increased at one degree Celsius Since the beginning of the industrial age, this actually translates into a month's advance in flowering - a result that is easy to see. Due to the fact that the world is only expected to continue warming, the British researchers predict that spring will arrive earlier and earlier in the country, and they warn that the functioning of the natural biological and ecological system, and the functioning of the agricultural system that feeds us all, are in unprecedented danger.
Go argue with the plants
The new study is the one with the most data that points to the advance of flowering in different regions of the world due to the climate crisis. However, evidence of the existence and worsening of the early rash has been increasing in recent years. Last year, for example, The earliest date was recorded of the iconic cherry blossom peak of the Kyoto region of Japan in the past 1,200 years. BFurther research from 2016 It has been found that in three-quarters of the national parks across the United States, blooming is coming earlier compared to the situation at the beginning of the 20th century.
What makes plants "decide" when to bloom? "Plants receive many signals from the environment that affect the initiation of flowering," explains Prof. Marcelo Sternberg, climate change ecologist at the School of Plant Sciences and Food Security at the Faculty of Life Sciences at Tel Aviv University. "Changes in temperature, the length of day and night and the humidity in the soil and air - the plants synthesize several factors, which affect their biological clock and lead to the production of flowers."
According to Sternberg, plants evolved over thousands of years under relatively stable climatic conditions, and today they are adapted to them. However, the climate crisis is bringing about a change whose rate is faster than the adaptive capacity of some species. "Plants can adapt to the new conditions, migrate or become extinct. If the genetic diversity of a plant does not allow it to adapt, and it does not have the ability to spread to new areas - then it will probably become extinct."
The flowers are waking up, the pollinators are still sleeping
One of the serious problems that may be caused to the natural environment due to a change in the flowering times is the formation of a mismatch between the flowering time and the activity period of various animals, such as pollinating insects, as well as birds for whom the nectar or the insects that depend on the flowering constitute an important source of food. in fact, Studies already indicate on such effects: in Japan, the plant Corydal (Corydalis ambigua) currently produces fewer seeds than before, due to the fact that its flowering was so early that the bees responsible for its pollination are not yet active at this time. "Plants that depend on pollination must synchronize between themselves and the pollinator," Sternberg explains. "If they bloom too early and insects are not yet active, there can be a failure in terms of the production of the fruit."
Another problem that can be caused by premature flowering is sometimes called "Mock Spring": This is a situation where uncharacteristically warm conditions appear early in the season - but later they "turn" back, and cold waves damage plants that have already begun to bloom. This phenomenon may also harm various agricultural crops, and lower the produce.
"The temperature greatly affects the quality of the flowering, and you can see a decrease in the flowering of all the deciduous trees - such as almonds, apricots and peaches," says Sternberg, who warns of a problem that harms these trees: "Especially in our region, an accumulation of cold days is necessary to produce good fruit in quantity greatness. If the winter is getting warmer, the ability to produce flowers, and later also fruits, is getting smaller and smaller."
The Israeli plants that bloom in December
Although in Israel no long-term study has been conducted documenting the flowering times of various species, in recent years early flowering events of trees such as almonds and herbs such as The mountain lupine - even in the month of December, so it is possible that even in Israel spring will arrive early. "Not only the warming has an effect, but also the timing of the rain and its distribution in the season", clarifies Sternberg, who heads a research station in the Judean Mountains where the effect of the drought conditions expected in the coming years on the natural systems is being tested.
"We need information based on the Mediterranean reality, which is different from the situation in Northern Europe," says Sternberg. "As far as our region is concerned, it's hard to be too optimistic."
According to him, not enough preparations have been made to deal with the changes that are expected to occur in our region. "The State of Israel needs a national program to study the climate crisis, to know what awaits us," he says. "We need to increase the number of programs dealing with adaptation to the climate crisis, work to reduce greenhouse gas emissions - and address our responsibilities as residents of Israel and the world."
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