【生態】道路沿いでの新生活に適応するサンショウウオ

Populations of spotted salamander in the northeastern United States have become adapted to life near roads, suggests a paper published in Scientific Reports. The global network of roads has expanded over the last half-century and continues to increase but although the ecological consequences of roads are well described, the evolutionary outcomes remain largely unevaluated. Steven Brady examined the effects of road adjacency on a pool-breeding amphibian, the spotted salamander (Ambystoma maculatum), by conducting a reciprocal transplant experiment across ten natural temporary pools, five near roads and five in woodland, comprising typical breeding sites for this species. The survival, growth and development of hatchling-stage larvae were measured. The roadside environment had strong negative impacts on embryonic salamander survival regardless of whether the animals originated from a roadside or woodland pool: the average survival rate of individuals in roadside pools was 56%, compared with 87% in woodland pools. Additionally, Brady found that in roadside pools, roadside-derived embryos out-survived those from woodland pools by 25%. The results provide further evidence that roads negatively affect species occupying road-adjacent habitats and the study reveals that even on small spatial scales, local population responses can describe substantial variation in capacity to tolerate anthropogenic environmental changes.