Consequences of Cultural Memory Loss in Migratory Ungulates Due to Selective Removal of Knowledge-Bearing Individuals

Abstract

Migratory ungulates depend on social knowledge to negotiate a complex environment, and the
disappearance of experienced individuals may interfere with cultural memory, efficiency in migration,
and population stability. The purpose of the study was to measure the ecological and behavioral effects
of the selective removal of knowledge-bearing individuals on the performance of migration, memory
of culture, and demographics. The used a composite Experience Index based on age, migratory
consistency, and social centrality to identify knowledge-bearing people. Migration performance was
measured based on the metrics of route fidelity and navigational efficiency, cultural memory based on
the Cultural Retention Index across successive generations, and population consequences by
population growth rate (λ) in a stage-structured demographic model. The analyses were made by
statistical techniques of generalized linear mixed models using bootstrapped confidence intervals to
consider repeated measurements and hierarchy. Findings show that knowledge-targeted removal had
a disproportionate impact on high-EI people (66.1%), in contrast to 25.5% when removal was random
and 36.4% when it was age-biased. Under focused removal, migration performance dropped
drastically, route fidelity fell from 0.82 ± 0.03 to 0.54 ± 0.06, and navigational efficiency fell from
0.87 ± 0.04 to 0.69 ± 0.06. CRI decreased between 0.63 and 0.41 in three generations, and the mean
migratory deviation had risen by 38%. The rate of population growth (λ) decreased 1.04 ± 0.02 to 0.96
± 0.03 with knowledge-targeted removal, which is a sign of lower reproductive success and high
mortality. Such findings show that knowledge-bearing individuals are one of the key nodes in
migratory networks. To retain migration fidelity, cultural continuity, and population resilience,
conservation strategies must focus on the protection of the socially experienced individuals. Other
interventions that can be addressed in future studies to reduce cultural memory loss include guided
reintroduction or social learning facilitation.