Urban environments promote adaptation to multiple stressors

Anthropogenic activities have drastically changed environmental conditions
worldwide, negatively impacting biodiversity and ecosystem services. At
the same time, the majority of the human population lives in urban areas
that are greatly altered from natural habitats. Nevertheless, many species
thrive in urban environments. To improve our knowledge of evolution and
adaptation in these anthropogenically impacted habitats, we conducted the
widest series of stress experiments to date with three marine taxa: one
mussel and two gammarid species. We compared intraspecific populations
from protected and human-altered habitats to determine their tolerance to
salinity, temperature and partial pressure of CO2 in water (pCO2) regimes.
Populations from impacted habitats typically outperformed protected
habitat populations, with individuals from the most impacted habitat being
the most robust. We propose that urban populations are adapting to life in
disturbed environments — this adaptation concurrently promotes more
resilient rescue populations but potentially confers increased invasion
risk from non-native species.