Harvest-induced evolution: insights from aquatic and terrestrial systems

Abstract

One contribution of 18 to a theme issue 'Human influences on evolution, and the ecological and societal consequences'. Commercial and recreational harvests create selection pressures for fitnessrelated phenotypic traits that are partly under genetic control. Consequently, harvesting can drive evolution in targeted traits. However, the quantification of harvest-induced evolutionary life history and phenotypic changes is challenging, because both density-dependent feedback and environmental changes may also affect these changes through phenotypic plasticity. Here, we synthesize current knowledge and uncertainties on six key points: (i) whether or not harvest-induced evolution is happening, (ii) whether or not it is beneficial, (iii) how it shapes biological systems, (iv) how it could be avoided, (v) its importance relative to other drivers of phenotypic changes, and (vi) whether or not it should be explicitly accounted for in management. We do this by reviewing findings from aquatic systems exposed to fishing and terrestrial systems targeted by hunting. Evidence from aquatic systems emphasizes evolutionary effects on age and size at maturity, while in terrestrial systems changes are seen in weapon size and date of parturition. We suggest that while harvest-induced evolution is likely to occur and negatively affect populations, the rate of evolutionary changes and their ecological implications can be managed efficiently by simply reducing harvest intensity.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.

Human influences on evolution, and the ecological and societal consequences

“…Strong and consistent directional selection might arise in any of the human-disturbance contexts, but we specifically wish to highlight hunting/harvesting, climate change and certain agricultural and human health situations. For hunting/harvesting, selection can actively target and disproportionately remove the largest individuals each generation, regardless of average body size [32]. Strong directional selection for smaller size thus should persist even as evolution proceeds.…”

Inefficiency of evolutionarily relevant selection in ungulate trophy hunting

“…Many of the oft‐cited papers on this subject speculate that hunter selection of ungulates with larger horns or antlers is intensive enough to cause detrimental evolutionary change throughout mountain sheep range, or even all hunted mammals (Harris et al , Festa‐Bianchet , Stenseth and Dunlop , Hedrick , Festa‐Bianchet et al ). Authors of other published works compared different taxa, sometimes in different areas (Skogland , Garel et al , Hengeveld and Festa‐Bianchet ), or make management recommendations to alleviate detrimental evolutionary effects of trophy hunting on ungulates with no evidence it is actually occurring (Festa‐Bianchet , Mysterud and Bischof , Pelletier et al , Kuparinen and Festa‐Bianchet ).…”

Adaptation to fragmentation: evolutionary dynamics driven by human influences

“…However, empirical evidence suggests that even key fitness traits can show significant heritability (e.g. mating system traits heritability: 0.3-0.4 [53], dispersal related traits heritability: 0.2-0.5 [45]), which would facilitate a rapid evolutionary response to fragmentation (see also [54]). A more important issue is the maintenance of genetic variation after fragmentation.…”