Nature is largely adapted to the current climate, making it more difficult to adapt to a new one

To do the right thing at the right time, organisms must pick up signals from their environment. With ongoing climate change, the timing of these signals, such as the build-up of warm days, is rapidly changing. Now a network of researchers working on an unprecedented dataset of seasonal events has shown that the timing of the species’ activity cannot keep up with their signals and that the rate at which the activity changes reflects the past evolution.

The observed patterns of local adaptation result in a massive footprint on nature’s calendar, making geographic variation in the timing of natural events more pronounced in spring and less pronounced in autumn. As organisms have evolved to respond differently in different areas, further evolutions will be needed to adapt to the new climate.

In nature, the activities of the species are programmed according to their environment. For plants to flower when their pollinators are around, for birds to reproduce when there is food for their chicks and then leave before snow covers the ground, they must follow the signs in their environment.

“One of these clues relates to temperatures: in warm years, all kinds of events tend to occur early, and in cold years they tend to occur late. How much events change with changes in temperature is described by something we call.” norm reaction, ”explains Professor Tomas Roslin, one of the study’s lead authors, who heads twin research groups at both the University of Helsinki and Uppsala, the Swedish University of Agricultural Sciences.

Because keeping track of the seasons is so important, it can be subject to selection in kind. Consequently, the reaction norms of the species can be adapted to their local environment. With a given cue change, individuals in one place can shift the timing of their activity more than in another. Now, what happens when the local environment changes, as it is doing now around the world?

To answer this question, the researchers collected meticulously collected observations of hundreds of seasonal phenomena occurring over decades at several hundred sites across the former Soviet Union. This huge dataset has opened up an unprecedented opportunity to explore responses to climate change over a huge area and a huge time scale.

Large local differences in how species respond to year-to-year variation

“We looked at events ranging from the first song of the great tit through the appearance of the common toad and the appearance of the first porcini mushroom to the end of the birch leaf fall,” says Maria Delgado, the other lead author of the study. from the University of Oviedo in Spain. “What we saw was a general rigidity in the response of the species to the year-to-year variation of the climate, ie at the beginning of the year, the more the time of the phenological event is later than the time of the signal from the temperatures.”

“Furthermore, we saw large differences between seasons and sites. Differences in the reaction norms of different sites accentuated the phenological responses in the spring and dampened them in the autumn. In the spring and less in the autumn than if all populations followed the same. reaction norm. Taken together, such models will influence species response to climate change in opposite ways in spring and autumn. ”

Built on numerical strength

The data that form the basis of the study is rather history, as it is based on a previously discovered archive of nature’s calendar. For many decades, in some cases an entire century, scientists have recorded events in more than 150 protected areas of the former Soviet Union. These data have been meticulously compiled as an annual report, one for each protected area. For a long time, this unique scientific contribution then remained hidden in the archives.

“But for the past decade we have been trying to mobilize this data. To do this, we have worked with a fantastic group of over 300 colleagues in over 80 organizations from Russia, Ukraine, Belarus, Kyrgyzstan and Uzbekistan,” explains Evgeniy Meyke, who together in Otso Ovaskainen he coordinated the database of the enormous material of the University of Helsinki.

Now compiled, the Chronicles of Nature program provides an outstanding archive in almost every aspect: it is comprehensive in nature and spans all kinds of species and events, long periods of time (nearly a century), large areas (mid- Asia), and was systematically collected by full-time dedicated scientific staff. Many participating scientists have spent their entire lives collecting this data, and by the time of publication, six had already died. The current document is therefore a tribute to their work.

“This has been an exciting journey – and it is only the beginning. We are thrilled with the enthusiasm of the environmental science professionals who have initiated this collaboration. They have given the world the opportunity to connect with the results of their lifelong work,” that had remained largely unknown to the international scientific community, “says Otso Ovaskainen, professor of mathematical ecology at the University of Helsinki, and the main driver behind the project. “Unfortunately, in most of the participating countries, protected areas and their personnel are facing difficult challenges. We hope that our results will attract the interest of the international community and focus attention on the global importance of these areas and on irreplaceable scientific work done by their staff. If these time series were to stop, there is no way to redo them. ”

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