An international team has investigated how chimpanzee behavior and behavior have been affected by human activity. The results are compelling: the culture of chimpanzees that they acquire over generations is losing diversity due to increasing human disturbance.
Like many of the organisms that inhabit this planet, chimpanzees have been subjected to enormous pressure by constant human activity, which has caused a change in its natural environment and therefore,a loss in its biodiversity. Their habitat - the humid tropical forests and the savannah - has been replaced by agricultural lands, plantations, settlements, or has been degraded by the extraction of natural resources.
A study published inSciencereveals that this pressure not only causes a loss of genetic diversity and ecosystem functions, but alsoit also affects cultural and behavioral diversity in chimpanzees, from the types of tools they use to the specific gestures they use in communication.
In short, "culture is specific behaviors of a group that young chimpanzees learn from generation to generation," he explains to Sinc,Ammie kalan, lead author of the study and primatologist at the Max Planck Institute for Evolutionary Anthropology (Germany).
Kalan along withHjalmar Kühl, also from the Primatology department of the Max Planck Institute and the German Center for Integrated Biodiversity Research (iDiv), have led an international team of researchers who have analyzed a set of31 behaviorsin 144 different communities, located throughout the entire geographic range of wild chimpanzees on the African continent.
A strong and robust pattern of cultural reduction
"Chimpanzees are highly intelligent and adaptable creatures," he says. Kevin lee, co-author of the study and a researcher at Arizona State University (USA), “there have been several reports of chimpanzees in captivity or close to humans that exhibit'novel' behaviors that are not observed in more remote populations, but it was not clear how the diversity of general behavior would be affected ”.
The team conducted an extensivefield work in 46 locations, as part of the Pan African Program, in15 range countries chimpanzees over the past nine years. The set of behaviors considered for this study included behaviors such asextraction and consumption from termites, ants, algae, nuts and honey;the use of tools for hunting or digging tubers, and the use of stones, pools and caves among others.
Human population density, roads, rivers and forest cover were some of the indicators used to determine the level of disturbance and the degree of change in the land cover of the chimpanzee habitat. "The analysis revealed a strong and robust pattern: chimpanzees had reduced behavioral diversity in places where human impact was high," Kalan says.
According to the researcher, we seean average loss of 88% of behaviors in chimpanzee communities living in areas with high human impact, compared to low impact areas.
What activities harm this diversity?
The size of a population plays an important role in maintaining cultural traits. Therefore, “the reduction of these communities due to threats such asThe hunt orhabitat fragmentation, causes a disruption in the social learning process of chimpanzees ”.
Degradation andresource depletion they can also diminish opportunities and thus prevent the transfer of local traditions from one generation to another.
This added toclimate change –Which influences the production of important food resources and makes their availability unpredictable– produces a combination of mechanisms that cause the reduction in the diversity of chimpanzee behavior.
More measures for conservation
"Our findings suggest that strategies for the conservation of biodiversityshould be expanded to also include the protection of the diversity of animal behavior ”, says Kühl, ecologist and co-leader of the study.
“Places with exceptional behaviors could be protected as‘chimpanzee cultural heritage areas‘ and this concept can be extended to other species with a high degree of cultural variability such as orangutans, capuchin monkeys or whales ”.
These proposals are in line with current biodiversity conservation efforts, such as the Convention on Biological Diversity or theConvention on the Conservation of Migratory Species of Wild Animals, of the United Nations Environment Program, calling for the protection of biological diversity in its entirety, including the behavioral diversity of culturally rich wildlife.
Kalan A., Kühl H. et al, "Human impact erodes chimpanzee behavioral diversity",Science, March 2019, DOI: http://science.sciencemag.org/lookup/doi/10.1126/science.aau4532