Motion 113

Human activities have caused a decline in old age classes of wild animal populations, whereby many of Earth’s oldest, often largest, and most experienced individuals have been eliminated from ecosystems. The ecological and socioeconomic consequences of this loss are poorly understood. The ecological and conservation importance of old individual animals has been neglected despite literature showing that old individuals provide distinct biological, ecological, cultural, and ecosystem service functions that are lost as aged individuals are eliminated.
Evidence from exploited populations shows a shift to younger age-classes, with the potential for harmful ecological, social, and economic consequences. Losing old individuals affects fundamental biological and ecological processes, including reproduction and recruitment, information acquisition and cultural transmission, trophic dynamics, and population resistance and resilience to ecological and anthropogenic disturbances. New research, policy, and longevity conservation actions are needed to protect and restore the distinct ecological roles and ecosystem services provided by older, often larger, and more experienced individuals across many taxa.
Longevity conservation should become an explicit objective for the local, national, and international management of certain species of fish and wildlife. Achieving this will require methods for detecting and measuring longevity depletion (i.e., age truncation) when formulating policies for sustainable fisheries, wildlife management, and the recovery of threatened species; and reducing avoidable mortality of old individuals, which is feasible using strategies such as age- and size-based harvest regulations, catch and release, time-area restrictions, and networks of interconnected protected areas to sustain large scale movements. We also need greater appreciation of the role of older individuals in reproduction, where the oldest may have the highest fecundity or mating success.
Research and management priorities should include understanding: how old animals may yield storage effects that enhance population resilience and community stability, especially with regards to exploited fish and wildlife; how older cohorts adapt to and recover from climate change and other anthropogenic pressures; trophic dynamics of old and large individuals and their role in food web structure and function; how knowledge, sociality, culture, decision-making, and other behaviors exhibited by older individuals influence social hierarchies, migration, habitat use, and survival; and how to implement policies and strategies to restore and protect the age structure of longevity-depleted populations.
It must also be noted that we do not yet have good knowledge of the potential for surviving to an old age in many species due to historical hunting or offtake. The further catastrophic loss of individuals who have the knowledge and ability to carry out large-scale movements or migrations leads to population-level restrictions of ranges. Such effects will have increasing consequences with range and habitat loss due to climate change. The ‘senescence-focused paradigm’ of old age has contributed to a misperception that older wild animals have declining reproductive and demographic value, and neglects consideration of their broader ecological roles. In some cases their loss has contributed to population and ecosystem declines.