Table 1.
Selected case studies of human-induced trait change, mechanisms tested, and demonstrated (D) or hypothetical (H) ecological effects. ‘Phenotypic’ studies employed wild organisms, whereas ‘genetic’ studies utilized common garden experiments or statistical methods to show a heritable basis for trait change. ‘Plastic’ studies subjected wild organisms to differing environmental conditions. The ‘evolution of plasticity’ has been demonstrated using the resurrection of resting eggs
| Case | Traits | Mechanism | Ecological effects | References |
|---|---|---|---|---|
| Habitat fragmentation on birds | Wing shape | Phenotypic | Metapopulation dynamics (H) | Desrochers (2010) |
| Supplemental feeding on European blackcap | Wing shape Beak shape | Phenotypic | Niche diversification (H) | Rolshausen et al. (2009) |
| Migratory direction | Genetic | Reproductive isolation (D) | Berthold et al. (1992) | |
| Dam construction on stream fishes | Body shape | Phenotypic Genetic | Trophic interactions (H) | Haas et al. (2010) Franssen et al. (2011) |
| Dam construction on alewife | Migratory behavior Gape size Gill raker spacing Prey selectivity | Phenotypic | Trophic cascade (D) Zooplankton community (D) Nutrient subsidies (D) | Post et al. (2008), Palkovacs and Post (2009), Walters et al. (2009) |
| Commercial fishing on marine top predators | Fish body size | Phenotypic | Trophic cascade (D) | Shackell et al. (2010) |
| Recreational fishing on largemouth bass | Metabolic rate Growth rate | Genetic | Social behavior (D) Trophic interactions (H) Nutrient excretion (H) | Cooke et al. (2007), Philipp et al. (2009), Redpath et al. (2009, 2010) |
| Trophy hunting on bighorn sheep | Horn size Body size | Genetic | Population growth (H) | Coltman et al. (2003) |
| Urbanization on seed dispersal | Dispersal structure on fruits | Genetic | Metapopulation dynamics (H) | Cheptou et al. (2008) |
| Fish introduction on Daphnia | Predator avoidance behavior | Evolution of plasticity | Trophic cascades (H) | Cousyn et al. (2001) |
| Eutrophication on Daphnia | Resistance to toxic cyanobacteria | Evolution of plasticity | Consumer-resource dynamics (H) | Hairston et al. (2001) |
| Elevated CO2 on plants | Leaf nitrogen composition | Plastic | Herbivore density (D) Herbivore feeding behavior (D) | Stiling et al. (2003) |
| Trout introduction on mayflies | Predator avoidance behavior | Plastic | Trophic cascades (D) | Peckarsky and McIntosh (1998) |