Human-induced rapid environmental change: A case study showing negative impact on animal culture

Abstract

Changes in land use in recent decades have caused substantial biodiversity loss. Some authors suggest that animal cultures could be threatened by human pressure. The tradition of nut-cracking has been thoroughly studied since 2005 in the capuchin monkeys (S. libidinosus) of Fazenda Boa Vista (FBV). Despite being a relatively well-preserved area, the advance of intensive monocultures in the proximity of FBV, among other factors, may have affected the environmental features of the region. In this contribution we investigated the hypothesis that the tradition of nut-cracking using stone tools by bearded capuchin monkeys at FBV is threatened by the rapid transformation of the habitat. We analyzed longitudinal climatic data (mean maximum and minimum temperature and mean maximum and minimum humidity) from 2006 to 2020, and data from the periods 2006–2010 and 2015–2020 for the variables related to nut-cracking: availability of palm trees bearing fruits, ground use and consumption of palm nuts by the monkeys. We show an increase in maximum temperature and a decrease in minimum temperature and minimum humidity over the study years. There was a sharp drop in the number of fruiting palm trees per hectare between the two study periods and a decrease in the time that monkeys spent on the ground, eating palm nuts, and nut-cracking with tools. We confirmed the hypothesis that the tradition of using tools in feeding is threatened. Our results show that in less than two decades, habitat anthropization already negatively impacts animal cultures. We emphasize the importance of considering behavioral diversity in conservation criteria.