Global urban environmental change drives adaptation in white clover.

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Human-induced evolution: Signatures, processes and mechanisms underneath anthropogenic footprints on natural systems

Abstract The impact of human activities on the global environment has increased to such an extent that the current geological era has been coined the Anthropocene. Studies dedicated to understanding the evolutionary consequences of human‐induced selection on all levels of diversity (species, populations, traits, genes) provide direct knowledge about the mechanisms underlying species' responses and their evolutionary potential. A better understanding of the effects of human‐induced selection is needed to leverage evolved mechanisms to develop appropriate conservation programmes to guarantee the maintenance of healthy systems. In this special issue, we focus on different types of human‐mediated selection pressures, from the direct harvesting of individuals (e.g. hunting, fishing), to the more pervasive effects of climate change. Contributions highlight the diversity of human‐induced selection pressures ranging from fisheries, trophy‐hunting, poaching and domestication to climate change, and pollution. With those, we question whether there are parallel evolutionary solutions across fisheries systems, whether hunting pressures alter population dynamics and population structure, and whether climate change is an evolutionary dead‐end. The contributions reflect the direction of travel of the field and the solutions to mitigate the impact of human activities

Urban hot-tubs: Local urbanization has profound effects on average and extreme temperatures in ponds

© 2018 Elsevier B.V. While urbanization-driven warming (urban heat island effect, UHI) has been extensively studied and demonstrated for air temperature, UHI effects on water temperature of ponds are unknown. We investigated (1) whether the UHI impacts man-made urban ponds and tested whether urban ponds have higher mean, maximum and minimum water temperatures and lower daily water temperature fluctuations than rural ponds, (2) whether this is related to time of the day (day versus night), season, and urbanization scale (3200 versus 50 m radius around the pond), and (3) whether the approximated length of growing season is prolonged in urban ponds. Temperature loggers were placed in 30 ponds in Northern Belgium, spanning a broad range of urbanization. We found strong evidence of urban-driven warming. Mainly local urbanization (50 m radius) drove temperature differences throughout the year and even more so in spring and summer, with mean summer temperatures being up to 3.04 °C higher in urban compared to rural ponds, and maximum summer temperatures on average up to 3.69 °C higher. Strikingly, daily temperature fluctuated around 2 °C more in locally urban ponds compared to rural ponds in summer. Length of the growing season estimates show prolongation with up to 45 days in locally urban compared to rural systems, mainly due to an earlier start. Generally, our results show that UHIs impact water temperature of ponds. This warming can have profound consequences for biota inhabiting these systems, and should therefore be considered in future urban planning to reduce deterioration of these habitats and improve their socio-ecological value.status: publishe