'Biodiversity is considered at three levels - at the level of ecosystems, at the level of inter-species and at the level of genes, or more precisely - intra-species genetic variability. When talking about protecting biodiversity, we often forget about the third, most basic level', says Aleksandra Biedrzycka, PhD, from the Institute of Nature Conservation of the Polish Academy of Sciences in Kraków. Meanwhile, the Convention on Biological Diversity and other international and EU regulations on nature conservation emphasise its importance.

Maciej Konopiński, PhD, from the Institute of Nature Conservation of the Polish Academy of Sciences in Kraków explains that genetic variability is the foundation of species evolution. It enables populations to find answers to problems that occur in the environment, such as the appearance of a new species of parasite, as well as climate change, including droughts or heavy rainfall. 'In order for individuals of a given population, a given species to cope with a new threat, survive and continue to reproduce, they need a set of tools, which are different gene variants', the scientist explains.

According to Konopiński, genetic variability (genetic diversity) can be compared to the set of tools we take on a long bicycle journey. These tools will not necessarily be useful every time, but you need to have them to survive in a crisis situation. 'The more limited your set of tools is, the more situations can interrupt your journey', the researcher says.

Aleksandra Biedrzycka and Maciej Konopiński took part in an international study, the results of which showthat over the course of over 30 years there has been a huge decline in genetic diversity on a global scale. A paper on this subject was published in the journal Nature at the end of January. Several dozen scientists - co-authors of the publication - performed a meta-analysis of the results of studies published in over 80 thousand journals in the years 1985-2019. They concerned monitoring changes in the scope of genetic diversity that occurred at two different points in time in 141 countries. In total, the analysis covered 628 species of animals, plants, fungi, inhabiting all land areas and many marine areas.

'Our analysis revealed that the decline in genetic diversity on a global scale is very common - it concerns two thirds of the species that were analysed. The greatest decline concerns birds and mammals', Biedrzycka says.

The researcher adds that because species diversity is decreasing (due to human activity), it has long been suspected that genetic variability is also decreasing. However, the research concerned primarily endangered species. 'What shocked us the most was the fact that, according to our analysis, genetic diversity is decreasing regardless of whether the species is endangered or common', Biedrzycka emphasises.

According to Konopiński, due to the global decline in biodiversity, some species that are key to human survival, such as pollinating insects, on which the yield of many crops depends, may not survive.

Biedrzycka reminds that in February 2025, a record low temperature was recorded - minus 40 degrees Celsius in the Tatra Mountains, and at the same time in Rio de Janeiro - 44 degrees Celsius, but above zero. 'Climate change occurs regardless of whether we believe that it is caused by humans - although scientific evidence confirms this. If individuals of a given species have gene variants that allow them to adapt to new climatic conditions, then this species has a better chance of survival', the researcher explains.

In her opinion, there may come a time when it will be necessary to abandon the protection of endangered species and focus on the protection of common species. 'Until now, nature conservation has focused on endangered species, and now it turns out that due to global climate change, the most important thing for humanity will probably be for entire ecosystems to survive and for species that are resistant, i.e. those that are usually the most common, to survive', Biedrzycka says.

The researchers point out that positive conclusions can also be drawn from the meta-analysis. 'We have assessed the methods used in nature conservation and it turns out that they can help maintain genetic variability, and sometimes they can also contribute to its improvement. Maintaining habitats, restoring them and creating connections between them - which is the main dogma of nature conservation - is unfortunately not enough', Biedrzycka says. She adds that more active methods of nature conservation management work, such as using individuals from populations with greater genetic variability to support populations that have less genetic diversity and are critically endangered.

The scientists mention the example of the capercaillie protection program in Poland. There are several isolated populations of this species that have been being rebuilt for about two decades. Capercaillies in Poland originate from two phylogenetic lines - from the north, more closely related to individuals from Sweden and Russia, and from the south, from the Carpathian phylogenetic line. 'Genetic studies have shown that they cannot interbreed, even though all these populations have low variability, because they differ too much from each other and this could harm them. That is why the northern populations are being supplemented with individuals brought from Sweden', Biedrzycka explains. She adds that the situation is similar with the lynx.

'Sometimes very specific actions are needed for a species whose genetic variability has decreased to survive', Konopiński says. He adds that maintaining genetic variability is extremely important, because the loss of genetic diversity is an irreversible threat. 'Restoring variability within a species that has lost it takes tens or even hundreds of thousands of years', the researcher emphasises.

The experts also point out that in Poland, activities aimed at maintaining genetic biodiversity, as well as biodiversity in general, are not coordinated by any institution. No standards have been set for biodiversity research and monitoring methods, conclude the scientists from the Polish Academy of Sciences.

Joanna Morga (PAP)

jjj/ bar/ js/