Biologists Warn About Decline in Genetic Diversity of Animals

A recent study on over 600 animal and plant species shows that genetic diversity worldwide has decreased, making it harder for living organisms to adapt to environmental changes. Researchers in this study, published in the journal 'Nature', examined data from 628 species collected between 1985 and 2019, finding the greatest decline in genetic diversity among birds and mammals. Before a species goes extinct, its population becomes smaller and more fragmented, reducing the number of potential mates and consequently genetic diversity. This situation makes species particularly vulnerable to future threats such as diseases. Intra-species diversity, meaning the differences among animals of the same species, allows their populations to better adapt to environmental changes. Catherine Gruber, an assistant professor at the University of Sydney and the senior researcher of this study, told The Guardian, 'If a new disease spreads, or a heatwave occurs, some individuals in a population may have traits that allow them to withstand the new conditions.' She added that these traits, passed on to the next generation, help the population survive instead of going extinct. Maintaining genetic diversity in wild and domesticated species was a key component of the goals established at the United Nations Biodiversity Conference in 2022. Many of the reasons leading to the decline in genetic diversity among animals are the same reasons that have caused their populations to decrease. Habitat loss, climate change, invasive species, and new diseases are some of the most significant causes. Researchers say that although the effects of environmental disturbances, including human exploitation, harassment, or land-use changes, have been observed in 65% of the studied populations, the loss of genetic diversity has also been seen among species that previously reported no disturbances. Gruber stated, 'One of the unexpected trends we observed is that genetic diversity has decreased even among many species that are not at risk.' She added that this reflects a broader biodiversity crisis that the Earth is facing, influenced by environmental disturbances such as climate change. However, Gruber points to several conservation projects where strategies implemented have improved genetic diversity. In one such case in the United States, conservation biologists were able to maintain genetic variability in black-tailed prairie dogs by applying pesticides to them. This prevented the spread of fleas and diseases like plague among this species, allowing the population to grow and increasing mating activity among them.