Erosion of animal cultures in fragmented landscapes

Abstract

In the study of fragmented populations, genetic diversity has received a good deal of attention, whereas traits that are not genetically inherited have been generally overlooked. We analyzed variation in cultural traditions (song and call repertoire) of a small songbird, Dupont's lark (Chersophilus duponti), with respect to landscape and demographic parameters associated with anthropogenic habitat fragmentation. As patch size, male population, and mean dispersal distance decrease, individual and population song repertoires pass through a cultural bottleneck and significantly decline in variety. Similarly, isolation is associated with impoverishment of population call pools. That declining populations face problems of cultural erosion, possibly anticipating extinction, suggests cultural diversity should be taken into account when dealing with the conservation of species in which social learning is important. Cultural elements could be viewed as a novel, fourth level of biodiversity that may complement the traditional dimensions of ecosystem, species, and genetic diversity. © The Ecological Society of America.